TRANSMISSION SYSTEM

Field of the Invention

The present invention relates to the field of vehicular power transmission systems, hi particular, the present invention relates to the field of protection of power transmission systems.

Background of the Invention

A power transmission system is a system for transferring power from an engine or motor to the point where useful work is applied, such as to vehicle wheels.

A driveshaft is a shaft in a power transmission system, which transfers power from one location to another, for instance from the front of a vehicle, where the engine and the gearbox are located, to the rear wheels thereof.

A universal joint is a joint that allows a rod, such as a driveshaft in a power transmission system, to 'bend' in any direction. It includes a pair of hinges oriented at 90° relative to each other.

A differential is a gearbox that receives rotational power from a driveshaft to drive a pair of wheels at different speeds. This feature is required during vehicle turns, for working the inward wheel a shorter distance than the outward wheel.

The driveshaft is usually strong enough to bear the torque, even upon sudden blocks. However, upon "sudden" blocks on the driveshaft, the weak components on the power transmission system, such as the universal joints and the differential, may be damaged.

It is an object of the present invention to protect the "weak" components of a power transmission system.

Other objects and advantages of the invention will become apparent as the description proceeds. Brief Description of the Drawings

The objects and features of the present invention will become apparent from the following detailed description considered in conjunction with the accompanying drawings, in which:

FIG. 1 illustrates a front view of the power protection unit (PPU) according to one embodiment of the present invention.

FIG. 2 illustrates the power protection unit of FIG. 1 adjusted to another example of torque threshold.

FIG. 3 illustrates a sectional view of the power protection unit (PPU) of FIG. 1 , disassembled.

FIG. 4 illustrates a sectional view of the power protection unit (PPU) of FIG. 1, assembled.

FIG. 5 is a zoom of FIG. 3, focusing on the discs of the second-side and the first-side shafts.

FIG. 6 is a two-dimensional linear illustration of the rotational movement of the discs of FIG. 5 in an engaged position.

FIG. 7 is a two-dimensional linear illustration of the rotational movement of the discs of FIG. 5 in a non-engaged position.

FIG. 8 is a two-dimensional linear illustration of the rotational movement of the discs of FIG. 5 in the next engaged position.

FIG. 9 illustrates a front view of the power protection unit (PPU) according to another embodiment of the present invention.

FIG. 10 illustrates the steps of mounting the power protection unit (PPU) of FIG. 1 to a shaft.

FIG. 11 illustrates the state of step 3 of FIG. 7 in a shaft of a vehicle. FIG. 12 illustrates another mounting of the power protection unit (PPU) on a shaft of a vehicle.

FIG. 13 is a two-dimensional linear illustration of the rotational movement of the discs in the engaged position of another embodiment of the Power Protection Unit.

FIG. 14 is a two-dimensional linear illustration of the rotational movement of the discs in the non-engaged position of the embodiment of Fig. 13.

FIG. 15 is a cross sectional view of the Power Protection Unit described by Fig. 13 according to one embodiment.

FIG. 16 is a top view of the disc of the Power Protection Unit described by

Fig. 13 according to the embodiment of Fig. 15.

FIG. 17 is a top view of the disc of the Power Protection Unit described by Fig. 13 according to another embodiment.

FIG. 18 is a top view of the disc of the Power Protection Unit described by Fig. 13 according to another embodiment.

It is to be understood, however, that the drawings are designed solely for purposes of illustration and not as a definition of the limits of the invention, for which reference should be made to the appended claims. It should be further understood that the drawings are not necessarily drawn to scale and that, unless otherwise indicated, are merely intended to conceptually illustrate the structures and procedures described herein. Reference numerals may be repeated among the figures in order to indicate corresponding or analogous elements.

Summary of the Invention

The following embodiments and aspects thereof are described and illustrated in conjunction with systems, tools methods, and so forth, which are meant to be merely illustrative, not limiting in scope. In one aspect, the present invention is directed to an apparatus for protecting components of a power transmission system of a vehicle, the apparatus comprising:

^■ a torque limiter (2), to be mounted on a driveshaft (12) of the vehicle transmission system, the torque limiter comprising:

• two shafts (4, 24), each having a disc (76, 58 correspondingly), wherein the discs are engageable by permanent engaging pressure;

• at least one springy element (54), for producing the permanent engaging pressure, thereby engaging the discs if the torque force on the driveshaft falls below a threshold, and disengaging the discs if the torque force exceeds the threshold; thereby preventing applying torque force beyond the threshold on the components of the transmission system, resulting in protecting the components of the transmission system.

The apparatus may further comprise mounting means (30, 32) on each of the shafts (4, 24), for enabling mounting the torque limiter on an existing driveshaft (12).

In other words, the mounting means allow mounting the apparatus (2) also in any transmission system, even if the transmission system was not designed to include the protection apparatus.

The mounting means may comprise a flange (30) having holes (32) for bolts.

The mounting means may comprise welding (Fig. 12) of the torque limiter to the driveshaft.

The apparatus may further comprise means for adjusting the applied engaging power on said discs seen in Fig 3).

The apparatus may further comprise an adjustable binder (26), for adjusting the permanent engagement pressure between the discs (76,58) , thus adjusting the torque threshold.

The apparatus may further comprise a scale (28) for viewing the adjusted torque threshold, according to the distance between the outward sides of the shafts.

The apparatus may further comprise complementary threads (68, 72) between the adjustable binder (26) and one of the shafts (24), for adjusting the placement of the adjustable binder (26) on that shaft (24).

The adjustable binder may comprise bolts (44), for adjusting the placement of the adjustable binder (26) on that shaft (24).

The engaging surfaces of the discs may comprise at least one engaged rotational position (Fig. 6, 13) between the discs, and at least one non-engaged rotational position (Fig. 7, 14) between the discs.

According to one embodiment, the surfaces of the discs (58, 76) may be wavy; the surface of one disc is complementary to the surface of the other (seen in Figs. 6 and 7), thereby generating an energy blockage threshold.

According to another embodiment the apparatus may further comprise at least two round objects (104) disposed between the discs (58, 76); according to this embodiment each of the surfaces of the discs (58, 76) may comprise at least two depressions (102 for 76, 106 for 58), each complementary to the round objects (104) for containing the round objects, thereby engaging (Fig. 13) the discs (58, 76) upon containing the round objects (104), and disengaging (Fig. 14) the discs upon removal of the round objects (104) from the containing.

Each of the round objects (104) may comprise a ball (Figs. 15, 16). According to another embodiment each of the round objects (104) may comprise a cylinder (Fig. 17), for utilizing the overall length (108) of the cylinder for the engagement, thereby providing extended surface for the engagement.

The cylinder may comprise a conical cylinder (Fig. 18) widening towards the external perimeter of the discs.

The widening of the conical cylinder may comprise (Fig. 18) an equal quotient between the perimeter of each surface (110, 112) of the cylinder (104) and the perimeter of the disc corresponding to that surface, thereby providing that the rotation of the disc (76, 58) upon disengagement, may rotate the narrow surface (110) of the cylinder (104) in the corresponding speed of the wide surface (112) thereof along a centered axis of rotation (48).

The apparatus may further comprise an alarm, for sounding upon disengagement between the discs.

The alarm may comprise: a gear (56) on one of the shafts; and a strap (74) on another of the shafts, the strap shaken by the gear, thereby producing distinguishable sound.

According to another embodiment the alarm may comprise: an electronic sensor, for sensing the disengagement between the discs; and an electronic indicator, for providing indication of that disengagement.

The apparatus may further comprise detachable attaching means (90), for detaching at least one of the discs (58) from the shaft thereof (24), for replacing the at least one of the discs. In addition to the exemplary aspects and embodiments described above, further aspects and embodiments will become apparent by reference to the figures and by study of the following detailed description.

Detailed Description of Preferred Embodiments

In the following detailed description, numerous specific details are set forth in order to provide a thorough understanding of the invention. However, it will be understood by those skilled in the art that the present invention may be practiced without these specific details. In some instances, well-known methods, procedures, components and circuits have not been described in detail, for the sake of brevity.

FIG. 1 illustrates a front view of the power protection unit (PPU) according to one embodiment of the present invention.

Power protection unit (PPU) 2 includes a first-side shaft 4 ending with a flange 30, a second-side shaft 24 ending with another flange 22, and a binder 26 for binding first-side shaft 4 to second-side shaft 24.

Each of flanges 30 and 22 includes holes 32 allowing firm and aligned mounting of PPU 2 using screws.

A clutch is a mechanism for transmitting rotation between two shafts, which can either be engaged to spin at the same speed, or disengaged to spin at different speeds.

First-side shaft 4 and second-side shaft 24 rotate together, such that the rotation of first-side shaft 4 transfers the power thereof to second-side shaft 24.

The term "torque threshold" refers herein to a predetermined level of the torque, above which the power transmission is not desired.

Above a certain torque the power transmission is not desired since it may damage the power transmission system. According to another application the power transmission is not desired above a torque indicating pre-determined overweight of the vehicle.

PPU 2 includes a torque limiter, which is a clutch designed for releasing power above a determined torque threshold, i.e. allowing rotation of first-side shaft 4 during a block on the rotation of second-side shaft 24.

Unlike common friction clutches which increase the engagement level between the two shafts as a function of the pressure therebetween ("analogue engagement"), the torque limiter is either engaged or disengaged ("digital engagement").

The torque threshold may be adjusted, depending on the depth of the placement of binder 26, as indicated by a scale 28.

According to the adjustment example of FIG. 1, in which numerals 1,2,3,4,5 of scale 28 are visible, the torque threshold is 5, which is the highest torque threshold, meaning that first-side shaft 4 will transfer rotating force thereof to second-side shaft 24 overcoming relatively strong blocks on second-side shaft 24.

FIG. 2 illustrates the power protection unit of FIG. 1 adjusted to another example of torque threshold.

Scale 28 of the state of FIG. 2, in which only numerals 1 and 2 are visible, indicates that the torque threshold is adjusted to 2, by binder 26. According to this example, first-side shaft 4 will rotate second-side shaft 24, overcoming only weak blocking on second-side shaft 24, and blocks above this weak blocking will still be released.

FIG. 3 illustrates a sectional view of the power protection unit (PPU) of FIG. 1 , disassembled.

First-side shaft 4 includes flange 30, a rod 62 wrapped by a spring 54, and a disc member 64 starting with a spring border 78, for limiting one side of spring 54. Second-side shaft 24 includes flange 22 and a sleeve 66 for housing rod 62 together with disc member 64 of first-side shaft 4. The second-side surface of sleeve 66 ends with a thread 68.

Spring 54 is limited at the other side by a border 70 of binder 26. The first- side surface of binder 26 includes a thread 72, which is complementary to thread 68 of second-side shaft 24.

FIG. 4 illustrates a sectional view of the power protection unit (PPU) of FIG. 1 , assembled.

Binder 26 is shown threaded on second-side shaft 24. Border 70 of binder 26 thus pushes one side of spring 54, such that the other side of spring 54 inserts disc member 64 of first-side shaft 4 into second-side shaft 24, engaging them.

The torque threshold adjustment is determined by the depth of the threading of thread 72 of binder 26 against spring 54 to thread 68 of first-side shaft 4. Deep threading squeezes spring 54 to provide strong engagement between discs 58 and 76.

In the assembled state of PPU 2, first-side shaft 4 rotates second-side shaft 24 due to complementary discs 58 and 76 engaged by spring 54.

FIG. 5 is a zoom of FIG. 3, focusing on the discs of the second-side and the first-side shafts.

Disc member 64 of first-side shaft 4 includes spring border 78 for limiting spring 54, and disc 76, for driving second-side shaft 24. Second-side shaft 24 includes disc 58, which is mounted to flange 22 thereof.

Disc 76 of first-side shaft 4 and disc 58 of second-side shaft 24 are complementary one to the other, having friction force between them, such that first- side shaft 4 rotates second-side shaft 24 upon the pressure of spring 54.

Blocking of disc 58 of second-side shaft 24 may temporally shrink spring 54 to allow disc 76 to rotate despite the blocking of torque limiter disc 76. A spherical hinge 86 (shown cut due to the sectional view) in a spherical aperture 88 may align the rotational movement of first-side shaft 4 in relation to second-side shaft 24.

A gear 56 on first-side shaft 4 shaking a strap 74 on second-side shaft 24 may be applied to sense and alarm rotational movement of first-side shaft 4 in relation to second-side shaft 24, for warning existence of a block, upon which PPU 2 releases power.

According to another embodiment the alarm may include electronic sensors, which may be electromechanical, optical, or others, activating visual or vocal indicators, in order to determine disengagement of the discs.

Preferably, disc 58 may be detached from second-side shaft 24 for being replaced, such as by releasing detachable attaching means of pins 90 thereof from second-side shaft 24, after decomposing PPU 2. In the same manner, disc 76 may also be replaced.

According to one embodiment the surfaces of disc 76 and of disc 58 include complementary wave forms, providing complementary rotational positions and non- complementary rotational positions between the discs 58 and 76.

For example, disc 76 features a wave form including depressions 82 and 84 and disc 58 includes a wave form including peaks 80 and 60. Peak 80 of disc 58 may be inserted in either of depressions 82 or 84 of disc 76.

Thus, disc 76 may rotate to skip from one rotational position on disc 58 to another.

FIG. 6 is a two-dimensional linear illustration of the rotational movement of the discs of FIG. 5 in an engaged position.

Discs 58 and 76 are engaged as peak 80 of disc 58 having height Y is inserted into depression 82 of disc 76 having height Y. Due to the engagement discs 58 and 76 rotate together in a direction, linearly illustrated by the arrows. FIG. 7 is a two-dimensional linear illustration of the rotational movement of the discs of FIG. 5 in a non-engaged position.

A block on the rotational movement of disc 58, above the torque threshold does not block disc 76, as disc 76 is automatically released from the engagement.

Depression 82 of disc 76 will be released from peak 80 of disc 58, such that disc 76 will rotate, bringing depression 82 of disc 76 to front a depression 94, by shrinking spring 54 (figuratively shown by 2Y).

Figs. 6 and 7 illustrates a cross section of the discs 58 and 76 in order to describe the surfaces thereof. The surface of each of discs 58 and 76 is wavy; the form of the wave of one disc is complementary to the form of the other disc, thereby enabling the discs to be in an engaged state, as illustrated in Fig. 6, or in a non- engaged state, as illustrated in Fig. 7.

The complement of the wavy form of the discs along with the permanent pressure of the discs generates an energy blockage to torque force. However, when a torque force of a certain level and above is applied on the discs, the discs disengage (as illustrated in Fig. 7).

The threshold on which the discs disengage depends mainly on the form of the waves and the applied engaging pressure.

The form of the waves does not have to be necessarily rounded, but also saw teeth, and the like.

FIG. 8 is a two-dimensional linear illustration of the rotational movement of the discs of FIG. 5 in the next engaged position.

From the position of FIG. 7, disc 76 continues rotating to the position where discs 58 and 76 are again engaged as extension 80 of disc 58 is inserted now into depression 84 of disc 76. Due to the new engagement, discs 58 and 76 have a new state of rotating together.

FIG. 9 illustrates a front view of the power protection unit (PPU) according to another embodiment of the present invention.

The torque threshold adjustment is determined by the depth of binding between first-side shaft 4 to second-side shaft 2. According to this embodiment, the depth of the binding is determined by bolts 44 instead of by threads 68 and 72. Unlike the adjustment by threads 68 and 72 that aligned by itself, according to this embodiment, the depth of the binding must be manually aligned. The alignment may be carried by ensuring the lines of scale 28 are parallel to the surface of border 70 of binder 26, and according to torque force on bolts 44, which should be substantially equal.

FIG. 10 illustrates the steps of mounting the power protection unit (PPU) of FIG. 1 to a shaft.

One of the vulnerable components, on which PPU 2 is intended to protect, is a universal joint 8. Universal joint 8 includes a pair of ordinary hinges 92 and 94 located close together, but oriented at 90° relative to each other, allowing a rod 40 to bend in relation to another rod 46. Universal joint 8 is commonly used in shafts including rods such as 40 and 46, which transfer rotary motion.

hi step 1, universal joint 8 joins rod 40 to rod 46 directly. In this state, universal joint 8 is not protected against a blocking force on the rotary motion.

In step 2, universal joint 8 is detached from rod 46 by opening bolts 42, separating flange 34 of universal joint 8 from flange 36 of rod 46.

In step 3, PPU 2 is mounted between universal joint 8 and rod 46, by hanging flange 30 of PPU 2 to flange 34 of universal joint 8 using bolts 42, and by hanging flange 22 of PPU 2 to flange 36 of rod 46, using bolts 42. In this state, PPU 2 may release power, to protect universal joint 8 from a block on the rotary motion.

FIG. 11 illustrates the state of step 3 of FIG. 7 in a vehicle shaft.

An engine 6 rotates a driveshaft 12 through a gear box 14, for driving wheels 96 through a differential 10.

PPU 2 mounted on driveshaft 12 may release the power produced by motor 6 upon an unexpected block 100 on wheels 96, such that the power of motor 6 will not be transferred to universal joints 8, universal joint 98 and differential 10, protecting each of them from breaking.

Additional PPU's 2 may be mounted on other axles or driveshafts. For instance another PPU 2 may be mounted on driveshaft/axle 16, between differential 10 and wheel 96.

FIG. 12 illustrates another method of mounting of the power protection unit (PPU) on a vehicle shaft.

In the case that there is no room for adding PPU 2 in an existing driveshaft 12, a portion of driveshaft 12 may be cut and removed. Then PPU 2 may be mounted by being welded to driveshaft 12 instead of being hung by flanges such as flanges 30 and 22, with bolts 42.

FIG. 13 is a two-dimensional linear illustration of the rotational movement of the discs in the engaged position of another embodiment of the Power Protection Unit.

The term "conical cylinder" refers herein to a cylinder having different radiuses at the top and bottom.

Fig. 13 is similar to Fig. 6, except that round objects 104, such as balls, cylinders or conical cylinders, engage the discs instead of the engagement by the complementary wavy surfaces of discs 58 and 76. Discs 58 and 76 are engaged since balls 104 are inserted between the depressions 102 and 106 thereof. Due to the engagement discs 58 and 76 rotate together in the direction, illustrated linearly by the arrows.

FIG. 14 is a two-dimensional linear illustration of the rotational movement of the discs in the non-engaged position of the embodiment of Fig. 13.

A block on the rotational movement of disc 58, above the torque threshold does not block disc 76, as disc 76 is released from the engagement. Disc 76 will rotate, by raising ball or cylinder or conical cylinder 104 above depression 102 of disc 76, by shrinking spring 54.

FIG. 15 is a cross sectional view of the Power Protection Unit described by

Fig. 13 according to one embodiment.

FIG. 16 is a top view of the disc of the Power Protection Unit described by Fig. 13 according to the embodiment of Fig. 15.

According to Figs. 15 and 16 PPU 2 may include a ball detent, meaning that the force between discs 58 and 76 is transmitted through hardened balls 104 which rest in detents.

However, ball 104 between discs 58 and 76 is disadvantage in having limited surface of applying engagement force. Typically, the highest point of ball 104 is a single point.

FIG. 17 is a top view of the disc of the Power Protection Unit described by

Fig. 13 according to another embodiment.

Fig. 17 is similar to Fig. 16, except that balls 104 are replaced by cylinders 104. Since the overall length 108 has the same height this engagement utilizes the overall length 108, thus overcoming the above-mentioned disadvantage of Figs. 15 and 16. However, since the external perimeter of discs 76 and 58 moves faster than the internal perimeter, cylinders 104 are disadvantaged of not fitting the rotational movement of the discs.

FIG. 18 is a top view of the disc of the Power Protection Unit described by Fig. 13 according to another embodiment.

Fig. 18 is similar to Fig. 17, except that cylinders 104 are replaced by conical cylinders 104, having larger radius at the external perimeter of discs 76 and 58.

The widening may be calculated to provide that the rotation of discs 76 and 58 rotates, upon disengagement, the narrow (small radius) surface 110 of cylinder in the corresponding speed of the wide (large radius) surface 112 thereof, such that the axis of the rotation 48 of conical cylinder 104 is centered. This overcomes the above- mentioned disadvantage of Figs. 17.

The calculation is that the quotient between the perimeter of the external surface 112 of cylinder 104 and the perimeter 116 of disc 76 corresponding to surface 112 is equal to the quotient between the perimeter of the internal surface 110 of cylinder 104 and the perimeter 114 of disc 76 corresponding to surface 110.

These equal quotients are also equal to the quotient between the perimeter of any intermediate surface between surfaces 110 and 112 of cylinder 104 and the intermediate perimeter between perimeter 114 and 116 of disc 76 corresponding to that intermediate surface.

In the figures and description herein, the following numerals and symbols have been mentioned: numeral 2 denotes an apparatus(PPU) according to one embodiment of the present invention; - numeral 4 denotes a first-side shaft; numeral 6 denotes an engine; numeral 8 denotes a universal joint; numeral 10 denotes a differential; numeral 12 denotes a driveshaft; numeral 14 denotes a gear box; numeral 16 denotes another driveshaft/axle example on which the PPU can be hung; ■ numeral 22 denotes a flange for mounting the power protection unit; numeral 24 denotes a second-side shaft; numeral 26 denotes an adjustable binder for binding the first-side shaft to the second-side shaft; numeral 28 denotes a scale indicating the adjusted torque threshold; - numeral 30 denotes a flange of the first-side shaft; numeral 32 denotes a hole on a flange for aligning the power protection unit

(PPU) on a driveshaft; numeral 34 denotes a flange of a universal unit; numeral 36 denotes a flange of a rod; - numeral 40 denotes a rod; numeral 42 denotes a bolt for hanging the flange of the PPU to the driveshaft; numeral 44 denotes a bolt for adjusting the placement of the adjustable binder; numeral 46 denotes a rod; numeral 48 denotes the axis of rotation of the cylinders; - numeral 54 denotes a spring; numeral 56 denotes a gear for alarm upon existence of a block; numeral 58 denotes a disc of the torque limiter; numeral 60 denotes a peak in the disc; - numeral 62 denotes a rod of the first-side shaft; ■ numeral 64 denotes a disc member, including a border for limiting the spring, and a gear for sounding an alarm upon existence of a block; numeral 66 denotes a sleeve of the second-side shaft, for housing the first-side shaft; numeral 68 denotes a thread; ■ numeral 70 denotes a border of the binder; numeral 72 denotes a thread; numeral 74 denotes a strap for producing noise upon different rotations of the first-side and second-side shaft; numeral 16 denotes another disc of the torque limiter; numeral 78 denotes a spring border, for limiting the spring; " numerals 80 denotes a peak on a disc; numerals 82 and 84 denote depressions on a disc; numeral 86 denotes a spherical hinge; numeral 88 denotes a spherical aperture;

- numeral 90 denotes a pin for attaching and detaching a disc from a shaft for replacement;

^■ numerals 92 and 94 denote hinges of a universal joint;

- numeral 96 denotes a wheel, such as of a vehicle; numeral 98 denotes a universal joint; numeral 100 denotes a physical block on the power transmission system, such as on a vehicle wheel; numeral 102 denotes a depression on a disc containing a round object; numeral 104 denotes the round object, which may be a ball, a cylinder, or a conical cylinder; numeral 106 denotes a depression on a disc containing the round object; " numeral 108 denotes the length of the cylinder; numeral 110 denotes the narrow surface of the conical cylinder; numeral 112 denotes the wide surface of the conical cylinder; numeral 114 denotes the perimeter of the disc at the internal portion of the cylinder; and - numeral 116 denotes the perimeter of the disc at the external portion of the cylinder.

While certain features of the invention have been illustrated and described herein, the invention can be embodied in other forms, ways, modifications, substitutions, changes, equivalents, and so forth. The foregoing description of the embodiments of the invention has been presented for the purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise form disclosed. Many modifications and variations are possible in light of this disclosure. It is intended that the scope of the invention be limited not by this detailed description, but rather by the claims appended hereto.