Background Art Generally, a torque converter which is mounted between an output shaft of an engine and an input shaft of a transmission, functions to control power transfer from an engine to an automatic transmission by using rotating force and vortex flow of fluid and to change output torque when transferring engine power to the automatic transmission.

Also, a torque converter which is used in an industrial machine, is mounted between an output shaft of an engine or a driving section and an input shaft of a transmission or a driven section, and functions to control power transfer from the engine to the input shaft by using rotating force and vortex flow of fluid and to change output torque when transferring engine power to the input shaft.

A torque converter of the present invention uses pressure-related characteristics of fluid and was made by modifying"Torque Converter for Automatic Transmission"

which is disclosed in Korean Patent Application No. 98- 28917 which was filed in the name of the present applicant.

FIGs. 18a and 18b illustrate a conventional torque converter, wherein FIG. 18a is a front cross-sectional view and FIG. 18b is a side cross-sectional view taken along the line XVIII-XVIII of FIG. 18a. Referring to FIGs. 18a and 18b, the conventional torque converter includes a housing 6 which defines a gear room 61 wherein a main gear Gl and a pair of auxiliary gears G2 are disposed. Four space portions 62 are arranged at upper and lower parts of the gear room 61 between the main gear G1 and the respective auxiliary gears G2. Two space portions 62 which are positioned in a diagonal direction, are communicated with each other by a fluid flowing passage 7. At a middle portion of the fluid flowing passage 7, there is disposed a spool 8 which is moved forward and backward by being driven by a separate power source. The spool 8 functions to interrupt or adjust fluid flow through the fluid flowing passages 7.

The main gear G1 is connected to an output shaft El of an engine E, and the housing 6 is connected to an input shaft T1 of a transmission T.

Accordingly, in the case that the fluid flowing passages 7 are opened and fluid flows through the opened fluid flowing passages 7, the main gear Gl and the pair of auxiliary gears G2 are idly rotated in the housing 6, whereby, although the output shaft El of the engine E is rotated, the housing 6 is maintained in a state wherein it is not rotated, and the input shaft Tl of the transmission T, which is connected to the housing 6, is not rotated (a situation wherein the engine E is idly rotated).

On the contrary, in the case that the fluid flowing passages 7 are blocked by the spool 8, fluid flow is interrupted. In other words, flow of fluid which is filled between teeth of the main gear Gl and the pair of auxiliary gears G2, is stopped. Accordingly, because the main gear G1 and the pair of auxiliary gears G2 are rigidly connected with each other through the fluid, as the main gear Gl which is connected to the output shaft El of the engine E, is rotated, rotating force of the main gear Gl is directly transferred to the housing 6, and thereby the input shaft T1 of the transmission T which is connected to the housing 6, is rotated (another situation wherein power of the engine E is fully transferred to the transmission T).

On the other hand, in the case that the fluid flowing passages 7 are partly opened, because fluid flows slowly through the opened fluid flowing passages 7, it is possible to change and transfer torque of the output shaft E1 of the engine E to the input shaft T1 of the transmission T.

However, the conventional torque converter constructed as mentioned above suffers from defects in that since the spool 8 which is mounted through the fluid flowing passage 7, must be moved forward and backward using the separate power source which is mounted outside the housing 6, it is difficult to provide a torque converter which is automatically operated in a state wherein it is interlocked with an accelerator of a vehicle or an actuating lever of an industrial machine.

Also, because the spool 8 which projects out of the housing 6, must be separately fabricated, in the case that the torque converter is mounted to the conventional

vehicle, the spool 8 is likely to be interfered with by various parts in an engine room. In addition, fabricating cost is increased.

Furthermore, since the torque converter is operated using the separate power source, it is difficult to apply the torque converter to a continuously variable transmission (CVT) which is operated without using a separate control section.

Disclosure of the Invention Accordingly, the present invention has been made in an effort to solve the problems occurring in the related art, and an object of the present invention is to provide a torque converter wherein a rotating spool which is operated by fluid, is mounted in front of a gear room which is defined inside a housing, whereby the torque converter is automatically controlled while it is interlocked with an accelerator of a vehicle or an actuating lever of an industrial machine.

Another object of the present invention is to provide a torque converter, wherein a rotating spool is mounted inside the torque converter thereby allowing the torque converter to be fabricated as a unified and self-contained arrangement, whereby the torque converter is not interfered with by other parts when the torque converter is arranged in an engine room, and fabricating cost is decreased.

Another object of the present invention is to provide a torque converter wherein two gear rooms are defined in two housings, respectively, a rotating spool is placed between the two gear rooms, helical gears which are connected to an input shaft of a transmission and two

pairs of auxiliary gears, are arranged at a side of one of the two housings, whereby the helical gears are brought into point contact one with another when an engine is idly rotated and thereby noise of the torque converter is reduced, and wherein the helical gears are formed in a manner such that a diameter of a pitch circle of an auxiliary helical gear is larger than that of a pitch circle of a main helical gear, whereby an rpm of the auxiliary helical gear is decreased and thereby noise generation of the torque converter is minimized.

Another object of the present invention is to provide a torque converter wherein gears which are disposed in two gear rooms, are arranged in a manner such that they have different pitch point positions thereby to be meshed with another gear at different times, respectively, whereby noise generation is minimized upon operation of the torque converter.

Still another object of the present invention is to provide a torque converter wherein a pair of rotating spools which control fluid flow through a gear room using centrifugal force, are arranged behind a pair of auxiliary gears, respectively, whereby, in the case that an rpm of a driving section reaches a predetermined value in connection with an operation of an accelerator, power of the driving section is automatically transferred to a driven section, and thereby the torque converter can be used as a clutch which is applied to a continuously variable transmission.

Yet still another object of the present invention is to provide a torque converter wherein an internal gear is fitted into a housing and a gear part which is constituted by a main gear and a pair of auxiliary gears, is disposed

in the internal gear, whereby, when power of an engine is transferred to a transmission, because compression force is generated at meshed portions among the main gear, the pair of auxiliary gears and the internal gear, wear of the gears can be minimized through dissipation of the compression force upon transferring engine torque.

In order to achieve the above objects, according to one aspect of the present invention, there is provided a torque converter operated by fluid pressure, comprising: a rotary input section including a housing and a cover, the housing being integrally secured to an engine output shaft and being formed with a gear room, the cover being assembled to the housing and being formed with a spool mounting groove; and an output section including a gear part and a rotating spool, the gear part being disposed in the gear room and having a main gear to which a transmission input shaft is connected and a pair of auxiliary gears, the rotating spool controlling flow of fluid which is filled in the gear room thereby to allow or prevent transfer of rotating force of the engine output shaft to the transmission input shaft.

According to another aspect of the present invention, there is provided a torque converter comprising: a rotary input section including a housing and a cover, the housing being integrally secured to an engine output shaft and having a mounting groove which is opened at one end thereof and into which an internal gear is fitted, the cover being assembled to the housing such that it closes the mounting groove of the housing and having a working fluid chamber; and an output section including a gear part and an operating spool, the gear part having a main gear which is meshed with the internal gear and to which the

transmission input shaft is secured, a pair of auxiliary gears which are located at both sides, respectively, of the main gear, and a pair of gear supporting members for supporting the main gear and the pair of auxiliary gears, the operating spool being reciprocatingly fitted into the mounting groove which is defined in the housing.

Brief Description of the Drawings The above objects, and other features and advantages of the present invention will become more apparent after a reading of the following detailed description when taken in conjunction with the drawings, in which: FIG. 1 is an exploded perspective view illustrating a torque converter in accordance with a first embodiment of the present invention; FIG. 2 is a cross-sectional view illustrating the torque converter of FIG. 1, which is in an assembled state; FIG. 3 is a partial exploded perspective view illustrating a pattern to which a housing and a cover are assembled with each other to constitute the torque converter of FIG. 1 ; FIGs. 4a and 4b are cross-sectional views taken along the line IV-IV of FIG. 2, wherein FIG. 4a illustrates a non-connection state of the torque converter of FIG. 1 and FIG. 4b illustrates a full connection state of the torque converter of FIG. 1; FIG. 5 is a schematic cross-sectional view illustrating another embodiment of a transmission input shaft mounting part of the torque converter of FIG. 1; FIG. 6 is a perspective view illustrating a first variation of the torque converter according to the first

embodiment of the present invention; FIG. 7 is an exploded perspective view of the first variation of the torque converter according to the first embodiment of the present invention; FIG. 8 is a cross-sectional view taken along the line VIII-VIII of FIG. 6 ; FIG. 9 is a cross-sectional view taken along the line IX-IX of FIG. 6; FIGs. 10a and 10b are cross-sectional views taken along the line X-X of FIG. 9, wherein FIG. 10a illustrates a non-connection state of the torque converter of FIG. 6 and FIG. 10b illustrates a full connection state of the torque converter of FIG. 6; FIG. 11 is a perspective view illustrating a second variation of the torque converter according to the first embodiment of the present invention; FIG. 12 is an exploded perspective view of the second variation of the torque converter according to the first embodiment of the present invention; FIG. 13 is a cross-sectional view taken along the line XIII-XIII of FIG. 11; FIGs. 14a and 14b are cross-sectional views taken along the line XIV-XIV of FIG. 11, wherein FIG. 14a illustrates a non-connection state of the torque converter of FIG. 11 and FIG. 14b illustrates a full connection state of the torque converter of FIG. 11; FIG. 15 is a perspective view illustrating a torque converter in accordance with a second embodiment of the present invention; FIG. 16 is an exploded perspective view illustrating the torque converter of FIG. 15; FIGs. 17a and 17b are cross-sectional views taken

along the line XVII-XVII of FIG. 15, wherein FIG. 17a illustrates a non-connection state of the torque converter of FIG. 15 and FIG. 17b illustrates a full connection state of the torque converter of FIG. 15; and FIGs. 18a and 18b illustrate a conventional torque converter, wherein FIG. 18a is a front cross-sectional view and FIG. 18b is a side cross-sectional view taken along the line XVIII-XVIII of FIG. 18a.

Best Mode for Carrying Out the Invention Reference will now be made in greater detail to a preferred embodiment of the invention, an example of which is illustrated in the accompanying drawings. Wherever possible, the same reference numerals will be used throughout the drawings and the description to refer to the same or like parts.

A torque converter according to the present invention is operated using fluid pressure. The torque converter largely includes a rotary input section 10,10'or 10" connected with an engine output shaft E1, to receive power which is generated in an engine; and an output section 20, 20'or 20"disposed inside the rotary input section 10,10' or 10"and including a plurality of gears which are interlocked with a transmission input shaft T1. The output section 20,20'or 20"functions to control flow of fluid which is filled in a space defined among the plurality of gears thereby to transfer torque of the engine output shaft El to the transmission input shaft Tl.

The rotary input section 10,10'or 10"encloses therein the output section 20,20'or 20". By the fact that the rotary input section 10,10'or 10"is connected to the engine output shaft El, the rotary input section

10,10'or 10"receives engine power and thereby is rotated integrally with the engine output shaft El.

The output section 20,20'or 20"is connected to the transmission input shaft Tl. The output section 20,20' or 20"includes at least one main gear G1 which is connected to the transmission input shaft T1, at least one pair of auxiliary gears G2 which are meshed with the main gear Gl, and means for controlling fluid which flows between teeth of the gears G1 and G2. The output section 20,20'or 20"receives rotating force of the rotary input section 10,10'or 10"through a rigid connection by the fluid and transfers it to the transmission input shaft Tl.

FIG. 1 is an exploded perspective view illustrating a torque converter in accordance with a first embodiment of the present invention. First, a construction of the torque converter in accordance with the first embodiment of the present invention will be described.

The torque converter in accordance with the first embodiment of the present invention includes a rotary input section 10 and an output section 20. The rotary input section 10 has a housing 11 and a cover 12. The housing 11 is integrally secured to the engine output shaft E1 and is formed with a gear room 111 and a pair of fluid discharging passages OH. The cover 12 is assembled to the housing 11 and is formed with a spool mounting groove 121. The spool mounting groove 121 has a circular groove portion 121a and a pair of fluid chambers 121b which are defined in a manner such that they are communicated with the circular groove portion 121a. Each fluid chamber 121b is communicated with a fluid supplying passage IH which is defined in the cover 12.

The output section 20 has a gear part 24 and a

rotating spool 21. The gear part 24 is disposed in the gear room 111 and has a main gear G1 to which the transmission input shaft T1 is connected and a pair of auxiliary gears G2. The rotating spool 21 controls flow of fluid which is filled in the gear room 111 thereby to allow or prevent transfer of rotating force of the engine output shaft El to the transmission input shaft T1.

FIG. 2 is a cross-sectional view illustrating the torque converter of FIG. 1, which is in an assembled state; FIG. 3 is a partial exploded perspective view illustrating a pattern to which a housing and a cover are assembled with each other to constitute the torque converter of FIG. 1; and FIGs. 4a and 4b are cross- sectional views taken along the line IV-IV of FIG. 2, wherein FIG. 4a illustrates a non-connection state of the torque converter of FIG. 1 and FIG. 4b illustrates a full connection state of the torque converter of FIG. 1. The pair of fluid chambers 121b of the spool mounting groove 121 which is formed in the cover 12, are spaced apart from each other by 180° along a circumferential direction thereby to be positioned opposite to each other. Each fluid chamber 121b has a sector-shaped configuration.

Each fluid supplying passage IH which is defined in the cover 12, is positioned adjacent to one end of the fluid chamber 121b along the circumferential direction. Each fluid discharging passage OH which is defined in the housing 11, is positioned adjacent to the other end of the fluid chamber 121b along the circumferential direction.

The rotating spool 21 which is fitted into the spool mounting groove 121, functions to interrupt or adjust fluid flow in the gear room 111. The rotating spool 21 has an annular ring portion 211 and a pair of vertical rod

portions 212. The annular ring portion 211 serves to open and close a front, that is, open end of the gear room 111.

The annular ring portion 211 is fitted into the circular groove portion 121a of the spool mounting groove 121 which is formed in the cover 12 and has a pair of fluid passing grooves 211a which are formed on a circumferential outer surface thereof in a manner such that they are spaced apart from each other by 180° along the circumferential direction. The pair of vertical rod portions 212 are integrally secured to the annular ring portion 211 in a manner such that they are spaced apart from each other by 180° and from the pair of fluid passing grooves 211a by 90° along the circumferential direction. The pair of vertical rod portions 212 are respectively fitted into the pair of fluid chambers 121b which are defined in the cover 12. Each of a pair of leaf springs 213 has one end which is secured to a bottom surface of each fluid chamber 121b adjacent to the other end of the fluid chamber 121b along the circumferential direction. On the other hand, the circumferential outer surface of the annular ring portion 211 of the rotating spool 21, which defines the pair of fluid passing grooves 211a, has, at each fluid passing groove 211a, a curved surface 211b. The curved surface 211b enables the controlling of fluid flow to be smoothly implemented when the rotating spool 21 is operated, thereby preventing an abrupt torque change. Also, as shown in FIG. 4, a pair of radial groove portions g are respectively defined adjacent to both ends of each fluid passing groove 211a on at least one surface of the rotating spool 21 thereby to form an oil film on the at least one surface of the rotating spool 21 and to ease rotation of the rotating spool 21.

A transmission shaft mounting section 22 is disposed at a center portion of the rotary input section 10. The transmission shaft mounting section 22 has a bracket 221 and a rotating shaft 222. The bracket 221 is formed with a pair of fluid supplying passages IH for supplying working fluid from a main pump of a vehicle into the pair of fluid chambers 121b, respectively, which constitute the spool mounting groove 121. The rotating shaft 222 is formed with a fluid discharging passage OH for discharging the working fluid from the pair of fluid chambers 121b to the main pump of the vehicle. The main pump is operated when an accelerator or an actuating lever is manipulated, thereby to supply or discharge the working fluid into or from the pair of fluid chambers 121b through the pair of fluid supplying passages IH or the fluid discharging passage OH.

In the meanwhile, FIG. 5 is a schematic cross- sectional view illustrating another embodiment of the transmission input shaft mounting part of the torque converter of FIG. 1. In a transmission input shaft mounting part 23 according to this embodiment of the present invention, structures of a bracket 231 and a rotating shaft 232 are the same as those of the first embodiment. In this embodiment, a hollow pipe P which is communicated at a distal end thereof with a pair of fluid supplying passages IH, is intervened between a circumferential inner surface of the bracket 231 and a circumferential outer surface of the rotating shaft 232 so that fluid can be supplied thereinto.

Hereinafter, operations of the torque converter according to the first embodiment of the present invention, constructed as mentioned above, will be

described in detail with reference to FIGs. 4a and 4b.

FIG. 4a illustrates a non-connection state of the torque converter of FIG. 1 (an idle rotation state of an engine). In FIG. 4a, because a preset amount of fluid is filled in the pair of fluid chambers 121b which are defined in the cover 12, the rotating spool 21 is maintained in a state wherein it is not rotated.

That is to say, due to the fact that boundary space portions between the main gear G1 and the pair of auxiliary gears G2 and upper and lower space portions which are arranged at upper and lower parts of the gear room 111, are opened through the pair of fluid passing grooves 211a which are defined in the annular ring portion 211 constituting the rotating spool 21 and that the fluid which is filled in the gear room 111, flows through the pair of fluid passing grooves 211a when the housing 11 which is connected to the engine output shaft E1 is rotated, the pair of auxiliary gears G2 which are meshed with the main gear G1, are idly rotated at both sides of the main gear Gl.

Therefore, since the main gear Gl which is connected to the transmission input shaft Tl, is not rotated, torque which is generated by the engine, is not transferred to a transmission.

On the contrary, FIG. 4b illustrates a full connection state of the torque converter of FIG. 1. If fluid is supplied through the pair of fluid supplying passages IH into the pair of fluid chambers 121b which are defined in the cover 12, the pair of vertical rod portions 212 of the rotating spool 21 are rotated in one direction.

Namely, as the pair of fluid passing grooves 211a which are formed at both sides of the annular ring portion

211 constituting tne rotating spool 21, are rotated about the transmission shaft mounting section 22, the boundary space portions between the main gear G1 and the pair of auxiliary gears G2 and the upper and lower space portions which are arranged at upper and lower parts of the gear room 111, are closed by the annular ring portion 211, whereby flow of fluid which is filled in the gear room 111 is stopped.

Consequently, at the same time when the housing 11 which is connected with the engine output shaft El is rotated, the main gear G1 is rotated and torque which is generated in the engine is transferred to the transmission. In other words, because the main gear Gl and the pair of auxiliary gears G2 are rigidly connected with each other through the fluid, the housing 11, the pair of auxiliary gears G2 and the main gear G1 are integrally rotated one with another.

On the other hand, in the case that it is required to cut off transfer of torque of the engine to the transmission while the vehicle is running or an industrial machine is operated, by freeing the accelerator or the operating lever, working fluid which is filled in the pair of fluid chambers 121b, is discharged through the pair of fluid supplying passages IH, and at the same time, the pair of leaf springs 213 each having one end which is secured to the bottom surface of each fluid chamber 121b adjacent to the other end of the fluid chamber 121b along the circumferential direction, are returned to their original positions, whereby the rotating spool 21 is returned to its initial position.

That is to say, as the pair of fluid passing grooves 211a which are formed at both sides of the annular ring

portion 211 constituting the rotating spool 21, open again the boundary space portions between the main gear Gl and the pair of auxiliary gears G2 and the upper and lower space portions which are arranged at upper and lower parts of the gear room 111, the fluid which is filled in the gear room 111, freely flows through the pair of fluid passing grooves 211a. Accordingly, the pair of auxiliary gears G2 which are disposed in the housing 11 which is connected to the engine output shaft El, are idly rotated at both sides of the main gear Gl.

Thus, the above-mentioned operations of the torque converter are repeatedly implemented while the vehicle is running or the industrial machine is being operated.

FIG. 6 is a perspective view illustrating a first variation of the torque converter according to the first embodiment of the present invention, and FIG. 7 is an exploded perspective view of the first variation of the torque converter according to the first embodiment of the present invention. A construction of the first variation of the torque converter according to the first embodiment of the present invention will be described.

The first variation of the torque converter according to the first embodiment of the present invention includes a rotary input section 10'and an output section 20'. The rotary input section 10'has a first housing 31, a second housing 32, a third housing 33 and a fourth housing 34.

The first housing 31 is integrally secured to the engine output shaft E1 and has a first gear room 311 which is defined therein. The second housing 32 has a spool mounting groove 321. The spool mounting groove 321 has a circular groove portion 321a and a pair of fluid chambers 321b which are defined in a manner such that they are

communicated with the circular groove portion 321a. Each fluid chamber 321b has a sector-shaped configuration. The third housing 33 has a second gear room 331 and a helical gear room 332 which are defined therein. The third housing 33 is formed with a pair of fluid supplying holes IH and a pair of fluid discharging holes OH. The fourth housing 34 is formed with a pair of fluid supplying passages IH and a pair of fluid discharging passages OH which are connected to a main pump of a vehicle.

Specifically, each of the pair of fluid supplying holes IH which are formed in the third housing 33, is positioned adjacent to one end of each fluid chamber 321b along a circumferential direction, which is defined in the second housing 32. Each of the pair of fluid discharging holes OH which are formed in the third housing 33, is positioned adjacent to the other end of each fluid chamber 321b along the circumferential direction. The pair of fluid supplying passages IH which are formed in the fourth housing 34, extend parallel to each other adjacent to upper and lower ends of the fourth housing 34. The pair of fluid discharging passages OH which are formed in the fourth housing 34, are connected with each other at a center portion of the transmission input shaft T1.

Moreover, the first and second gear rooms 311 and 331 which are formed in the first and third housings 31 and 33, respectively, are filled with working fluid. By the fact that upper and lower space portions are arranged at upper and lower parts of the first and second gear rooms 311 and 331 and at boundary regions between the main gear G1 and the pair of auxiliary gears G2, it is possible to ease flow of fluid which is filled in the first and second gear rooms 311 and 331.

As can be readily seen from FIGs. 7 and 8, the output section 20'has a first gear part 41, a second gear part 42, a rotating spool 43 and a helical gear part 44. The first gear part 41 has a first main gear G1 and a pair of first auxiliary gears G2 which are disposed in the first gear room 311. The second gear part 42 has a second main gear G1 and a pair of second auxiliary gears G2 which are disposed in the second gear room 331. The rotating spool 43 controls flow of fluid which is filled in the first and second gear rooms 311 and 331 and is fitted into the spool mounting groove 321 which is formed in the second housing 32. The helical gear part 44 has a main helical gear Hl and a pair of auxiliary helical gears H2. The main helical gear Hl is fitted into the helical gear room 332 and is connected to the transmission input shaft Tl. The pair of auxiliary helical gears H2 are located at both sides of the main helical gear H1 and are connected with the pairs of first and second auxiliary gears G2 through a pair of connection shafts 441, respectively.

In particular, by forming the helical gear part 44 in a manner such that a pitch circle of the main helical gear HI which constitutes the helical gear part 44, has a diameter which is greater than that of a pitch circle of the auxiliary helical gear H2, an rpm of each auxiliary helical gear H2 can be minimized. Therefore, as the rpm of the auxiliary gears H2 which constitute the first and second gear parts 41 and 42, is reduced, noise generation is minimized when the engine is idly rotated.

FIG. 9 is a cross-sectional view taken along the line IX-IX of FIG. 6; and FIGs. 10a and 10b are cross-sectional views taken along the line X-X of FIG. 9, wherein FIG. 10a illustrates a non-connection state of the torque converter

of FIG. 6 and FIG. 10b illustrates a full connection state of the torque converter of FIG. 6. The rotating spool 43 has a circular plate portion 431 and a pair of vertical rod portions 432. The circular plate portion 431 has a pair of fluid passing grooves 431a which are formed on a circumferential outer surface thereof in a manner such that they are spaced apart from each other by 180° along the circumferential direction. The pair of vertical rod portions 432 are integrally secured to the circular plate portion 431 in a manner such that they are spaced apart from each other by 180° and from the pair of fluid passing grooves 431a by 90° along the circumferential direction.

The pair of vertical rod portions 432 have a pair of springs 433 which are secured at one end thereof to the pair of vertical rod portions 432, respectively. The circumferential outer surface of the circular plate portion 431 of the rotating spool 43, which defines the pair of fluid passing grooves 431a, has, at each fluid passing groove 431a, a curved surface 431b which enables the controlling of fluid flow to be smoothly implemented.

In the meanwhile, as shown in FIG. lOb, the first and second main gears G1 which are disposed in the first and second gear rooms 311 and 331, respectively, are arranged in a manner such that they have different pitch point positions thereby to be meshed with the two pairs of first and second auxiliary gears G2 at different times, respectively. Further, the two pairs of first and second auxiliary gears G2 which are disposed in the first and second gear rooms 311 and 331, respectively, are arranged in a manner such that they have different pitch point positions thereby to be meshed with the first and second main gears Gl at different times, respectively.

Accordingly, because the teeth of the first main gear Gl and the pair of first auxiliary gears G2 and the teeth of the second main gear Gl and the pair of second auxiliary gears G2 are meshed one with another at different times, noise generation is minimized.

Hereinafter, operations of the first variation of the torque converter according to the first embodiment of the present invention, constructed as mentioned above, will be described in detail.

First, a non-connection state of the torque converter (an idle rotation state of an engine) will be described with reference to FIGs. 9 and 10a.

As can be readily seen from the drawings, as the fluid supplying and discharging holes IH and OH and the fluid supplying and discharging passages IH and OH which are formed in the third and fourth housings 33 and 34, are maintained in a closed state, flow of fluid which is filled in the pair of fluid chambers 321b which is defined adjacent to upper and lower ends of the second housing 32, is stopped. Therefore, a position of the operating spool 43 which is disposed in the spool mounting hole 321, is not altered. That is to say, the pair of fluid passing grooves 431a which are formed at both sides, respectively, of the circular plate portion 431 constituting the rotating spool 43, are placed at the boundary regions between the main gear Gl and the pair of auxiliary gears G2.

At this time, the main helical gear Hl of the helical gear part 44 which is mounted to the fourth housing 34, is connected to the transmission input shaft T1, and the pair of auxiliary helical gears H2 which are provided at both sides of the main helical gear Hl, are simultaneously

rotated with the first through fourth housings 31,32,33 and 34 which are connected to the engine output shaft El.

By this, the two pairs of first and second auxiliary gears G2 of the first and second gear parts 41 and 42 which are connected to the pair of auxiliary helical gears H2, are also rotated, and the two main gears G1 of the first and second gear parts 41 and 42 are idly rotated. Namely, as the boundary regions between the main gears G1 and the pairs of auxiliary gears G2 which constitute the first and second gear parts 41 and 42, are opened, the fluid which is filled in the first and second gear rooms 311 and 331, can be freely circulated. Accordingly, the pair of auxiliary helical gears H2 are idly rotated about the main helical gear Hl.

As a result, because the main helical gear H1 which is connected to the transmission input shaft Tl is not rotated, the idle rotation state of the engine, wherein torque which is generated in the engine is not transferred to the transmission, is accomplished.

Next, a full connection state of the torque converter will be described with reference to FIGs. 9 and lOb.

While the engine is idly rotated as described above, if the accelerator or the actuating lever is manipulated by a driver or an operator, fluid is supplied into the pairs of fluid supplying holes and passages IH which are formed in the third and fourth housings 33 and 34 from the main pump which are operated in an interlocked manner with the accelerator, and fluid is discharged from the pairs of fluid discharging holes and passages OH which are formed in the third and fourth housings 33 and 34 to the main pump.

Accordingly, by the fact that the fluid is supplied

to the pair of fluid chambers 321b through the pair of fluid supplying holes IH each of which is formed adjacent to one end of each fluid chamber 321b, the pair of vertical rod portions 432 of the rotating spool 43 are rotated in one direction. In other words, as the pair of fluid passing grooves 431a which are formed at both sides, respectively, of the circular plate portion 431 constituting the rotating spool 43, are rotated, boundary space portions between the first and second main gears Gl and the pairs of first and second auxiliary gears G2 and upper and lower space portions which are arranged at upper and lower parts of the first and second gear rooms 311 and 331, are closed by the circular plate portion 431, whereby flow of fluid which is filled in the first and second gear rooms 311 and 331, is interrupted.

Hence, because the first and second main gears Gl and the pairs of first and second auxiliary gears G2 are rigidly connected with each other through the fluid, at the same time when the first through fourth housings 31, 32,33 and 34 which are connected to the engine output shaft E1 are rotated, the main gears Gl, the pairs of auxiliary gears G2, the main helical gear H1 and the pair of auxiliary helical gears H2 are integrally rotated one with another, thereby to transfer torque which is generated in the engine, to the transmission.

On the other hand, in the case that it is required to cut off transfer of torque of the engine to the transmission while the vehicle is running or an industrial machine is being operated, by freeing the accelerator or the operating lever, fluid is supplied into the pair of fluid chambers 321b through the pairs of fluid discharging holes and passages OH, and at the same time, as the pair

of springs 433 wh-ch-» re mounted at sides, respectively, of the pair of vertical rod portions 432 constituting the rotating spool 43, are returned to their original positions, the rotating spool 43 is returned to its initial position.

That is to say, as the pair of fluid passing grooves 431a which are formed at both sides of the circular plate portion 431 constituting the rotating spool 43, open again the boundary space portions between the first and second main gears G1 and the pairs of first and second auxiliary gears G2 and the upper and lower space portions which are arranged at upper and lower parts of the gear rooms 311 and 331, the fluid which is filled in the first and second gear rooms 311 and 331, freely flows through the pair of fluid passing grooves 431a. Accordingly, the first through fourth housings 31,32,33 and 34 which are connected to the engine output shaft E1 are rotated, and the pairs of first and second auxiliary gears G2 of the first and second gear parts 41 and 42 are idly rotated about the first and second main gears Gl, respectively.

At this time, since the pairs of first and second auxiliary gears G2 are rotated at a low speed via the helical gear part 44, it is possible to prevent torque from being abruptly changed and when the vehicle is stopped after running, residual torque which is remained in the transmission input shaft T1, can be minimized.

FIG. 11 is a perspective view illustrating a second variation of the torque converter according to the first embodiment of the present invention, and FIG. 12 is an exploded perspective view of the second variation of the torque converter according to the first embodiment of the present invention.

A construction of the second variation of the torque converter according to the first embodiment of the present invention will be described.

The second variation of the torque converter according to the first embodiment of the present invention includes a rotary input section 10"and an output section 20". The rotary input section 10"comprises a housing 51 and a cover 52. The housing 51 is integrally secured to the engine output shaft El and has a gear room 511 which is defined therein. The gear room 511 includes a main gear room 511a and a pair of auxiliary gear rooms 511b which are filled with fluid. The cover 52 is assembled to the housing 51 and has a pair of spool mounting grooves 521 which are defined therein in a manner such that they face the pair of auxiliary gear rooms 511b, respectively.

Each of the pair of spool mounting grooves 521 has a circular groove portion 521a and a moving space portion 521b which is communicated with the circular groove portion 521a and is filled with fluid.

The output section 20"has a gear part 61 and a rotating spool part 62. The gear part 61 is disposed in the gear room 511 of the housing 51 and has a main gear G1 which is connected with the transmission input shaft T1 and a pair of auxiliary gears G2 which are located at both sides, respectively, of the main gear Gl. The rotating spool part 62 has a pair of rotating plates 621 each of which is fitted into the circular groove portion 521a of the spool mounting groove 521 and is formed with a fluid passing groove 611a. Each of the pair of rotating plates 621 has a vertical rod portion 622 which is secured thereto. The vertical rod portion 622 has a spring 622b which is fastened thereto and is formed with a fluid

passing hole 622a which extends therethrough.

Specifically, a circumferential outer surface of each rotating plate 621 constituting the rotating spool part 62, which defines the fluid passing groove 611a, includes a curved surface 611b.

FIG. 13 is a cross-sectional view taken along the line XIII-XIII or FIG. 11. The main gear G1 which is disposed in the housing 51, is connected to the transmission input shaft T1 which extends through a center portion of the cover 52, and the engine output shaft El is connected to a front central portion of the housing 51.

Accordingly, when the engine output shaft E1 is rotated, the housing 51 is rotated at the same rpm with the engine output shaft El.

FIGs. 14a and 14b are cross-sectional views taken along the line XIV-XIV of FIG. 11, wherein FIG. 14a illustrates a non-connection state of the torque converter of FIG. 11 and FIG. 14b illustrates a full connection state of the torque converter of FIG. 11. Fluid is filled in the pair of moving space portions 521b constituting the pair of spool mounting grooves 521 which are formed at both sides of the cover 52. As described above, the vertical rod portion 622 constituting each rotating plate 621 is formed with the fluid passing hole 622a which extends therethrough. Accordingly, in the case that the rotating spool part 62 is rotated due to centrifugal force which is generated by the rotation of the housing 51 and the cover 52, the fluid flows through the pair of fluid passing grooves 611a, whereby rotation of the rotating spool part 62 is smoothly implemented. Further, a spring mounting groove is formed in the cover 52 at one end of each moving space portion 521b. The spring mounting

groove serves to prevent the spring 622b from being inadvertently released from the moving space portion 521b.

In particular, by the fact that the circumferential outer surface of each rotating plate 621 constituting the rotating spool part 62, which defines the fluid passing groove 611a, includes the curved surface 611b, smooth fluid flow is ensured in the gear room 511 when the rotating spool part 62 is rotated.

In addition, working fluid is filled in the gear room 511 which is formed in the housing 51. Also, upper and lower space portions are arranged at upper and lower parts of the gear room 511 at boundary regions between the main gear G1 and the pair of auxiliary gears G2 which are disposed in the gear room 511, whereby flow of fluid which is filled in the gear room 511, is smoothly implemented.

Hereinafter, operations of the second variation of the torque converter according to the first embodiment of the present invention, constructed as mentioned above, will be described in detail.

First, a non-connection state of the torque converter (an idle rotation state of a driving section) will be described with reference to FIGs. 13 and 14a.

For example, as a driver of a vehicle inserts an ignition key into a key groove, if the engine output shaft E1 is rotated at 800 rpm, the housing 51 and the cover 52 which are connected to the engine output shaft El, are integrally rotated.

However, because centrifugal force which is generated in the case that the housing 51 is rotated at such a low speed, is flimsy, the centrifugal force cannot overcome elastic force of the spring 622b which is mounted adjacent to an upper end of each rotating plate 621. Accordingly,

the pair of fluid passing grooves 611a which are formed in the pair of rotating plates 621, respectively, maintain a state wherein the boundary regions between the main gear Gl and the pair of auxiliary gears G2 which are disposed in the gear room 511 are opened, and according to this, the fluid which is filled in the gear room 511, flows smoothly along the pair of fluid passing grooves 611a. By this, the pair of auxiliary gears G2 are idly rotated about the main gear G1. In other words, as the fluid which is filled in the gear room 511 is circulated, the fluid which resides in the boundary regions between the main gear Gl and the pair of auxiliary gears G2, continuously flows, whereby the pair of auxiliary gears G2 are idly rotated about the main gear G1.

Therefore, by the fact that the main gear G1 which is connected to the engine output shaft El is not rotated, the idle rotation state of the driving section, wherein torque which is generated in the driving section is not transferred to the transmission, is accomplished.

Next, a full connection state of the torque converter will be described with reference to FIGs. 13 and 14b.

While the engine is idly rotated as described above, if the accelerator is manipulated by the driver, an rpm of the driving section which is operated in an interlocked manner with the accelerator, is increased to 2,000 rpm.

In proportion to the increase of the rpm, centrifugal force which is generated in the housing 51 and the cover 52, is also increased. Accordingly, as the centrifugal force overcomes the elastic force of the spring 622b which is mounted adjacent to the upper end of each rotating plate 621, the rotating spool part 62 which is constituted by the pair of rotating plates 621, is rotated in a

clockwise direction.

Consequently, as the pair of fluid passing grooves 611a which are formed in the pair of rotating plates 621, respectively, are rotated, boundary space portions between the main gear Gl and the pair of auxiliary gears G2 which constitute the gear part 61 and the upper and lower space portions which are arranged upper and lower parts of the gear room 511, are closed by the pair of rotating plates 621. By this, flow of fluid which is filled in the gear room 511, is interrupted.

Thus, by the fact that the main gear Gl and the pair of auxiliary gears G2 are rigidly connected with each other by the fluid, at the same time when the housing 51 which is connected to the engine output shaft El is rotated, the main gear G1 which is meshed with the pair of auxiliary gears G2, is rotated. According to this, as the transmission input shaft Tl which is connected to the main gear Gl is rotated, torque which is generated in the driving section is transferred to the transmission.

On the other hand, in the case that it is required to cut off transfer of torque of the driving section while the vehicle is running, by freeing the accelerator, an rpm of the driving section is decreased and at the same time, centrifugal force which is generated by the housing 51 is also decreased. Hence, due to the elastic returning force of the pair of springs 622b which are mounted adjacent to the upper ends of the pair of rotating plates 621, the rotating spool part 62 is rotated in a counterclockwise direction thereby to be returned to its initial position.

In other words, as the pair of fluid passing grooves 611a which are formed in the pair of rotating plates 621, respectively, constituting the rotating spool part 62,

open again the boundary space portions between the main gear Gl and the pair of auxiliary gears G2 and the upper and lower space portions which are arranged at upper and lower parts of the gear room 511, the fluid which is filled in the gear room 511 freely flows through the pair of fluid passing grooves 611a. Accordingly, the housing 51 and the cover 52 which are connected to the engine output shaft E1 are idly rotated about the main gear Gl along with the pair of auxiliary gears G2.

In the meanwhile, while the second variation of the present invention was described in association with the vehicle, it is to be readily understood that the second variation of the present invention can be applied to a continuously variable transmission of an industrial machine.

FIG. 15 is a perspective view illustrating a torque converter in accordance with a second embodiment of the present invention; and FIG. 16 is an exploded perspective view illustrating the torque converter of FIG. 15. First, a construction of the torque converter in accordance with the second embodiment of the present invention will be described.

The torque converter in accordance with the second embodiment of the present invention includes a rotary input section 70 and an output section 80. The rotary input section 70 has a housing 71 and a cover 72. The housing 71 is integrally secured to the engine output shaft E1 and has a mounting groove 711 into which an internal gear 711a is fitted and a pair of fluid discharging passages OH which are formed in a manner such that they are spaced apart from each other by 180° along a circumferential direction and are communicated with each

other at a center portion of the transmission input shaft Tl. The cover 72 is assembled to the housing 71 such that it closes the mounting groove 711 of the housing 71 and has a working fluid chamber 721 which is communicated with a main pump of a vehicle through a pair of fluid supplying passages IH.

The output section 80 includes a gear part 81 and an operating spool 82. The gear part 81 has a main gear G1 which is meshed with the internal gear 711a and to which the transmission input shaft T1 is secured, a pair of auxiliary gears G2 which are located at both sides, respectively, of the main gear Gl, and a pair of gear supporting members 811 for supporting the main gear G1 and the pair of auxiliary gears G2. The operating spool 82 is reciprocatingly fitted into the mounting groove 711 which is defined in the housing 71.

Specifically, as shown in FIGs. 16 and 17, a first circumferential groove 712 is defined in the housing 71 inside the mounting groove 711, and a second circumferential groove 825 is defined on one surface of the operating spool 82. A pair of annular rings 83 are disposed adjacent to the pair of gear supporting members 811 in a manner such that they sandwich the pair of gear supporting members 811 therebetween. The pair of annular rings 83 are connected to the pair of auxiliary gears G2 through a pair of shafts 831, respectively, and are rotatably inserted into the first and second circumferential grooves 712 and 825, respectively.

Therefore, the pair of annular rings 83 function to guide the pair of auxiliary gears G2 while the pair of auxiliary gears G2 are rotated and/or orbited.

On the other hand, a pair of springs 822 are

intervened between a bottom surface of the second circumferential groove 825 which is defined on the one surface of the operating spool 82 and one surface of the annular ring 83 which adjoins the operating spool 82. The operating spool 82 is formed with at least one fluid passing hole 823, and a circumferential sleeve portion 824 is formed along an edge of the operating spool 82 on the other surface of the operating spool 82.

The working fluid chamber 721 is formed in the cover 72 adjacent to an edge portion of an inner surface of the cover 72, and the circumferential sleeve portion 824 of the operating spool 82 is inserted into the working fluid chamber 721. The working fluid chamber 721 is communicated with a main pump through the pair of fluid supplying passages IH.

Hereinafter, operations of the torque converter according to the second embodiment of the present invention, constructed as mentioned above, will be described in detail.

First, a non-connection state of the torque converter (an idle rotation state of an engine) will be described with reference to FIG. 17a.

As can be readily seen from FIG. 17a, as the fluid supplying and discharging passages IH and OH which are formed in the cover 72, are maintained in a closed state, the operating spool 82 which is inserted into the mounting groove 711 which is defined in the housing 71, is maintained in a retracted position, whereby fluid which is filled in the internal gear 711a, can freely flow.

Therefore, at the same time when the internal gear 711a of the housing 71 which is connected to the engine output shaft E1 is rotated, the pair of auxiliary gears G2

which are meshed with the internal gear 711a are rotated and orbited, whereby the main gear Gl which is connected to the transmission input shaft T1 is maintained in a stopped state.

Consequently, by the fact that the main gear Gl which is connected to the transmission input shaft T1 is not rotated, the idle rotation state of the engine, wherein torque which is generated in the engine is not transferred to the transmission, is accomplished.

Next, a full connection state of the torque converter will be described with reference to FIG. 17b.

While the engine is idly rotated as described above, if an accelerator or an actuating lever is manipulated, fluid is supplied from the main pump which is operated in an interlocked manner with the accelerator or the actuating lever, into the working fluid chamber 721 which is formed in the cover 72, and at the same time, fluid is discharged from the pair of fluid discharging passages OH which are defined in the housing 71. Accordingly, the circumferential sleeve portion 824 of the operating spool 82, which is inserted into the working fluid chamber 721, is moved to an extended or projected position. By this, as an inner surface of the operating spool 82 is brought into close contact with the internal gear 711a, the main gear Gl and the pair of auxiliary gears G2, flow of fluid which is filled in the internal gear 711a, is interrupted.

Consequently, because the fluid which is filled in the internal gear 711a is maintained in a substantially solidified state, at the same time when the housing 71 which is connected to the engine output shaft El is rotated, the internal gear 711a, the main gear G1 and the pair of auxiliary gears G2 are integrally rotated, whereby

torque which is generated in the engine is transferred to the transmission. That is to say, the pair of auxiliary gears G2 which are meshed with the internal gear 711a, are stopped, and the main gear Gl which is meshed with the pair of auxiliary aears G2 is also stopped. At this time, the housing 71, the internal gear 711a, the main gear G1 and the pair of auxiliary gears G2 are integrally rotated one with another.

On the other hand, in the case that it is required to cut off transfer of torque of the engine to the transmission while the vehicle is running or an industrial machine is operated, as shown in FIG. 17a, by freeing the accelerator or the operating lever, the operating spool 82 which is disposed in the housing 71, is retracted by elastic force of the pair of springs 822 which are brought into close contact with the pair of gear supporting members 811 and through discharging of the fluid which is filled in the working fluid chamber 721.

As a result, as fluid which is filled in the internal gear 711a freely flows, the housing 71 and the internal gear 711a are rotated, and at the same time, as the pair of auxiliary gears G2 which are meshed with the internal gear 711a are rotated and orbited, the main gear G1 which is connected to the transmission input shaft Tl is maintained in a stopped state.

Industrial Applicability The torque converter according to the present invention, constructed as mentioned above, provides advantages in that, since the torque converter is operated in an interlocked manner with an accelerator, a separate apparatus for controlling the torque converter is not

needed.

Also, because a rotating spool is mounted inside the torque converter, the torque converter is not interfered with by any other parts when the torque converter is arranged in an engine room, whereby the torque converter can be easily mounted to an existing vehicle and thereby fabricating cost can be lessened.

In addition, by the fact that a transmission input shaft and a helical gear part are connected with each other, noise generation of the torque converter is reduced, an rpm of an auxiliary gear which is connected to an auxiliary helical gear is minimized, and thereby noise generation of the torque converter is further reduced.

Moreover, due to the fact that gears which are disposed in two gear rooms, are arranged in a manner such that they have different pitch point positions thereby to be meshed with another gear at different times, respectively, noise generation is minimized upon operation of the torque converter.

Further, in the case that an rpm of a driving section reaches a predetermined value in connection with an operation of an accelerator, power of the driving section is automatically transferred to a driven section, whereby the torque converter according to the present invention can be used as a clutch which is applied to a continuously variable transmission for an industrial machine.

Furthermore, because compression force is generated at meshed portions among an internal gear, a main gear and a pair of auxiliary gears which are disposed in a housing, wear of the gears can be minimized through dissipation of the compression force upon transferring engine torque to the transmission.

In the drawings and specification, there have been disclosed typical preferred embodiments of the invention and, although specific terms are employed, they are used in a generic and descriptive sense only and not for purposes of limitation, the scope of the invention being set forth in the following claims.