Technical field

The present invention relates to a transmission with a continuously variable transmission ratio between a driving shaft and a driven shaft. The transmission is also suitable for cases when it is required to keep the sense of rotation of the driven shaft regardless to the sense of rotation of the driving shaft.

Background of the Invention

Known technical solutions of transmissions with a continuously variable transmission ratio comprise so-called drive conversion units or variable speed gear-boxes. These transmissions are mostly based on a friction- gearing. Their disadvantage consists in wearing of moving parts and decreased efficiency due to the friction between the moving parts. Moreover they have a relatively small and limited range of transmission ratios.

Further there exist transmissions combining hydrostatic and mechanical principles. Their disadvantage includes loss of efficiency caused mainly by the hydraulic elements.

• Summary of the Invention

The presented disadvantages are to a great extend removed by a transmission with a continuously variable transmission ratio designed according to the invention, the subject matter of which includes a driving shaft having a driving flange with a driving pin, the axial distance of which with respect to the driving shaft axis is adjustable by means of a control mechanism. On the said driving pin there is seated a first eye of a connecting rod the second eye of. which is seated on a driven pin of a swinging arm positioned by means of a free wheel on a driven shaft.

According to another subject matter of the invention on a driving shaft there is arranged a driving pin carrying a first eye of a connecting rod the second eye of which is seated on a driven pin of a swinging arm positioned by means of a free wheel on a driven shaft, the axial distance of the driven pin with respect to the driven shaft axis being adjustable by means of a control mechanism.

According to still another subject matter of the invention a driving flange with a driving pin is arranged on a driving shaft, an axial distance of the driving pin with respect to the driving shaft axis being adjustable by the first control mechanism, while on the said driving pin there is seated a first eye of a connecting rod the second eye of which is seated on a driven pin of a swinging arm positioned by means of a free wheel on a driven shaft and an axial distance of the driven pin with respect to the driven shaft axis being adjustable by the second control mechanism.

Further in accordance with the invention the driving flange is provided with a radial slot providing for a sliding fit of the driving pin.

Still further in accordance with the invention the swinging arm is provided with a longitudinal slot providing for a sliding fit of the driven pin.

in a preferred embodiment of the invention the driven shaft is seated in the transmission casing by means of a second free wheel.

According to a preferred feature of the invention the control mechanism of the driving pin consists of a planet flange attached to the driving shaft and spaced apart from the driving flange, the planet flange having a second journal, which extends towards the driving flange and provides for a seat of a second planet pinion engaging simultaneously with a gearing on the inside surface of the transmission casing and with a gear wheel located in a running fit on the driving shaft. The gear wheel engages with a first pianet pinion, being in a sliding fit mounted on a first journai and engaging with internal teeth of a control wheel. The first journal is attached at one side of an

^• adjusting disc located in a running fit on the driving shaft, while the other side of the adjusting disc, which faces the driving flange, is provided with a spiral groove into which there extends a slider of the driving pin.

The transmission according the invention eliminates application of a standard clutch between a motor and a gear box. It also keeps a sense of rotation of the driven shaft irrespective to the actual sense of rotation of the driving shaft as may be the case e.g. by changing of poles of an electric motor. Brief Description of the Drawings

The invention is further described in details by way of examples presented in the accompanying drawings, where

Fig. 1 presents a kinematical diagrammatic plan of the transmission according to the first preferred embodiment and

Fig. 2 shows a principal arrangement of the transmission first embodiment,

Fig. 3 presents a kinematical diagrammatic plan of the transmission according to the second preferred embodiment and

Fig. 4 shows a principal arrangement of the transmission second embodiment,

Fig. 5 presents a kinematical diagrammatic plan of the transmission according to the third preferred embodiment and

Fig. 6 shows a principal arrangement of the transmission third embodiment,

Fig. 7 shows a principal arrangement of the control mechanism with the driving pin shown in both turning points.

Description of Preferred Embodiments

The first preferred embodiment of a transmission with continuously variable gear ratio according the present invention, the kinematical principle of which is shown in Fig. 1 and principle embodiment in Fig. 2, comprise a transmission casing 10 being known as such, a driving shaft 1, a driven shaft 8 and further presented elements. On the driving shaft 1 there is arranged a driving flange 2, in the said embodiment provided for by a disc-shaped plate co-axially arranged at the end of the driving shaft ±. The driving flange 2 may have even a different, non-circular shape, eventually it may be provided for by an adjustable arm. The driving flange 2 is provided with a driving pin 3, which in a preferred embodiment is made of a solid cylinder but can be also made of a short tube. Αn ^τ axial distance of the driving pin 3 axes with respect to the driving shaft 1 axis is adjustable by means of a control mechanism 9. The preferred design of the control mechanism 9 is presented in Fig. 7 and in details shall be described below. Nevertheless the control mechanism 9 may be provided for by any other mechanism known as such, provided such a mechanism allows for a continuous shift of the driving pin 3 on the driving

95 flange 2 during rotation of the driving shaft 1 with the driving flange 2.

On the driving pin 3 there is seated a first eye of a connecting rod 4, the second eye of which is seated on a driven pin 5. The connecting rod 4 in the presented design has a shape of a slim rod. In a preferred embodiment its shape is similar to the one used by combustion engines which are therefore ioo ^' known as such, but it is slimmer and longer. The driven pin 5 is connected with a swinging arm 6, arranged on the driven shaft 8 by means of a free wheel 7. In the presented embodiment the driven pin 5 is made of a solid cylinder but can be made also of a short tube or alternatively it may form an integral part of the swinging arm 6. As said above the swinging arm 6 is

105 seated on the driven shaft 8 by means of a free wheel 7. It can be of any design known as such, e.g. of a cylinder or a segment type. The free wheei 7 provides for a transfer of motion of the swinging arm 6 upon rotation of the driven shaft 8 in the selected sense of rotation.

The preferred sense of rotation is the one by which the connecting rod 4 is no . under tensile stress.' The swinging arm 6 motion is generated by rotation of the driving shaft 1 having the driving flange 2 with the driving pin 3, the driving pin 3 being by means of the connecting rod 4 attached to the driven pin 5. The swinging arm 6 motion ranges, incl. a total still stand, are determined by mutual positions of the driving shaft 1 axis and the driving

115 pin 3 axis as obvious from Figs. 1 and 2.

In a case when the driving pin 3 is in a position indicated by the letter A, as shown on Fig. 1 , when the driving pin 3 axis is coaxial with the with the driving shaft 1 axis the swinging arm 6 motion range is zero, i.e. the angle a = 0. In this moment even when the driving shaft 1 rotates the driven shaft 8

120 is in a still stand. When the driving pin 4 is moved to the C position, see Fig. 1 , i.e. when its axis is in the maximal distance from the driving shaft i axis, the swinging arm 6 motion range is at its maximum, as shown by angle γ. When the driving pin 3 is moved to the B position, see Fig. 1 , i.e. when its axis is in a position between the A and C positions, the swinging arm 6 motion range 125 corresponds to the angle β.

Mutual positions of the driving shaft and the driving pin 3 are continuousiy variable by means of the control mechanism 9, the example embodiment of which is shown in Fig. 7. The control mechanism 9 performs radial shift of the driving pin 3 within a radial slot 21 of the driving flange 2. In the presented

130 embodiment the control mechanism 9 comprise an adjusting disc 91 arranged in a revolving seat at the driving shaft 1, preferably by a ball bearing. The adjusting disc 9_1 is positioned very close to the driving flange 2 face on the side opposite the position of the driving pin 3, _. The driving pin 3, protruding through the radial slot 21, is provided with a slider 3J. which is

135 shaped to fit into a spiral groove 911 arranged in the disc 9_1 surface facing the driving flange 2. The slider 3J _. thus extends from the radial slot 21 on the

. side opposing the driving pin 3 position. On the side opposite the spiral groove 911 the control disc 9J_ is furnished with a first journal 931 providing for a seat of the first planet pinion 93 with external teeth.

140 The first planet pinion 93 engages with external teeth of a gear wheel 92 with external teeth, the gear wheel 92 being by means of a bearing seated on the driving shaft 1 adjacent to the control disc 9J.. With the gear wheel 92 there engages also a second planet pinion 94 arranged in a revolving seat on a second journal 941 mounted on a planet flange 97. The planet flange 97 is

145 provided for by a disc-shaped plate rigidly mounted on the driving wheel next to the gear wheel 92, thϋs-by both the gear wheel 92 and the control disc 9_1 spaced apart form the driving flange 2.

The second planet pinion 94 engages with internal teeth of an internal gear wheel 9Jj, which in this case forms an integral part of the transmission

150 casing 10: The first planet pinion 93 engages with internal teeth of an adjusting wheel 96. Revolving of the adjusting wheel 96 with respect to the transmission casing 10 is transferred by the system of the above described wheels 93,92,94,95 upon ^' the control disc ^' 9J[, which therefore revolves with respect to the driving flange 2. The adjusting wheel 96 is arranged in a

155 revolving seat within the transmission casing 10.. I here can be used even more planet pinions located at the control disc 91 pins together with further planet pinions arranged at pins mounted on the planet flange 97.

The adjusting wheel 96 may be revolved by mechanical, electromechanicai,

160 electrical or any other means according to a control system of the transmission. The control mechanism 9 continuously varies the eccentricity of the driving pin 3 with respect to the driving shaft 1, i.e. the distance of the driving pin 3 axis from the driving shaft 1 axis and with it the transmission ratio between the driving shaft 1 and the driven shaft 8. The driving pin 3 is

165 shifted within the radial slot 21 from the first limit position when the driving pin 3 axis . is coaxial with the driving shaft 1 axis, see A position in Fig.1 , to the second limit position, see the dashed position of the driving pin 3 in Fig. 7, which corresponds to the C position shown in Fig. 1.

For applications of the transmission according the invention for siow speeds no it is preferred to arrange the driven shaft 8 in the transmission casing 10 by means of a second free wheel 7. This arrangement aliows for no change of sense of rotation of the driven shaft 8 by reverse motion of the swinging arm 6.

The second preferred embodiment, the kinematics of which is demonstrated in

175 Fig. 3 and a principle arrangement shown in Fig. 4, offers a transmission with a variable transmission ratio regulation, the transmission comprising a transmission casing 10 being known as such, a driving shaft 1, a driven shaft 8 and further presented elements. On the driving shaft 1 there is arranged a driving flange 2, in the said embodiment provided for by a disc-shaped plate co-axialiy arranged iso at the end of the driving shaft 1. The driving flange 2 may have even a different, non-circular shape, eventually -there may be used no driving flange 2, the driving pin 3 being mounted directly on the driving shaft 1, its axis being parallel to but not coaxial with the driving shaft ±. The driving flange 2 is provided with a driving pin 3, which in a preferred embodiment is

185 ^" made of a solid cylinder but can be made also of a short tube. By this embodiment the axial distance of the driving pin 3 axes with respect to the driving shaft 1 axis remains ^; constant. On the driving pin 3 there is seated a first eye of a connecting rod 4, the second eye of which is seated on a driven pin 5. The connecting rod 4 in the

190 presented design has a shape of a slim rod. in a preferred embodiment its shape is similar to the one used by combustion engines which are therefore known as such, but it is slimmer and longer. In the presented embodiment the driven pin 5 is made of a solid cylinder but can be also made of a short tube. The driven pin 5 is arranged in a sliding seat in a longitudinal slot 61

195 of the swinging arm 6. arranged on the driven shaft 8 by means of a free wheel 7. The free wheel 7 can be of any design known as such, e.g. of a cylinder or a segment type The free wheel 7 provides for a transfer of motion of the swinging arm 6 upon rotation of the driven shaft 8 in a selected sense of rotation.

200 The preferred sense of rotation is the one by which the connecting rod 4 is under tensile stress. By preferred embodiment of the transmission according the invention for slow-speed applications the driven shaft 8 is seated in the transmission casing IQ by means of a second free wheel 7 which shall provide for no change of rotation of the driven shaft 8 by reverse motion of

205 the swinging arm 6.

The swinging arm 6 motion is generated by rotation of the driving shaft 1 with the driving flange 2 having the driving pin 3, the driving pin 3 being by means of the connecting rod '4 coupled with the driven pin 5. The swinging arm 6 motion ranges are determined by a mutual position of driven pin 5 axis and

2io the driven shaft 8 axis. The said distance, i.e. the position of the driven pin 5 axis with respect to the driven shaft 8 axis is performed by the control mechanism 9. The control mechanism 9 may be provided for by any other mechanism known as such, provided such a mechanism allows for a continuous radial shift of the driven pin 5 within the longitudinal slot 61 of the

215 swinging arm 6 while the arm swings. The control mechanism 9 continuously changes the eccentricity of the driven pin 5 with respect the driven shaft 8, i.e. the distance of the driven pin 5 axis from the driven shaft 8 axis thereby continuously changing the transmission ration between the driving shaft 1 and the driven shaft 8.-In this very embodiment the swinging arm 6 cannot be 220 fully stopped while the driving shaft lstili rotates, as is the case by the first preferred embodiment. As said above and can be seen from Figs 3 and 4, the swinging arm 6 motion ranges are determined by mutual positions of driven pin 5 axis and the driven shaft 8 axis.

When the driven pin 5 is in the C position, see Fig. 3, i.e. when the driven

225 pin 3 axis is in the maximal distance from the driven shaft 8 axis, the swinging arm 6 movement range is at its minimum, as shown by angle γ. When the driving pin 4 is moved to the D position, see Fig. 3, i.e. when the driven pin 3 axis is in , a minimal distance from the driven shaft 8 axis, the swinging arm 6 movement range is at its maximum, as shown by the angle 0.

230 All the said positions are obvious from Figs. 3 and 4.

The third preferred embodiment, the kinematics of which is demonstrated in Fig. 5 and a principle arrangement shown in Fig. 6, offers a transmission with a variable transmission ratio regulation, the transmission comprising a transmission casing 10 being known as such, a driving shaft i, a driven shaft 8 and further

235 presented elements. On the driving shaft 1 there is arranged a driving flange 2, in the said embodiment provided for by a disc-shaped plate co-axiai!y arranged at the end of the driving shaft Λ_. The driving flange 2 may have even a different, non-circular shape, eventually it can be designed as an

. adjustable arm. The driving flange 2 is provided with a driving pin 3, which in

240 a preferred embodiment is made of a solid cylinder but can be also made of a short tube.

The axial distance of the driving pin 3 axes with respect to the driving shaft 1 axis is adjustable by means of a control mechanism 9. An example of this design is described in details above by description of the first preferred

245 embodiment. The control mechanism 9 may be provided for by any other mechanism known as such, provided such a mechanism aliows for a continuous shift of the driving pin 3 on the driving flange 2 during rotation of the driving shaft 1 with the driving flange 2.

On the driving pin 3 there is seated a first eye of a connecting rod 4, the

250 second eye of which is seated on a driven pin 5. The connecting rod 4 in the presented design has a shape of a slim rod. In a preferred embodiment its shape is similar to the one used by combustion engines which are therefore known as such, but it is slimmer and longer. The driven pin 5 is arranged in a sliding seat in a longitudinal slot 61 of the swinging arm 6, which is seated on

255 the driven shaft 8 by means of a free wheel 7. The free wheel 7 can be of any design known as such, e.g. of a cylinder or a ^" segment type. The free wheel 7 provides for a transfer of motion of the swinging arm 6 upon rotation of the driven shaft 8 only in a selected sense of rotation.

The preferred sense of rotation is the one by which the connecting rod 4 is

260 under tensile stress. For applications of the transmission according the invention for slow speeds it is preferred to arrange the driven shaft 8 in the transmission casing 10 by means of a second free wheel 7. This arrangement allows for no change of sense of rotation of the driven shaft 8 by reverse motion of the swinging arm 6.

265 The swinging arm 6 motion is generated by rotation of the driving shaft 1

^■ having the driving flange 2 with the driving pin 3, the driving pin 3 being by means of the connecting rod 4 attached to the driven pin 5. The swinging arm 6 motion ranges in this case are determined by combined effect of mutual positions of the driving shaft 1 axis with respect to the driving pin 3

270 axis and the driven pin 5 axis with respect to driven shaft 8 axis. The adjustment of the first and second individual axis distances are performed by the respective control mechanisms as described by the first and second preferred embodiments respectively. As it is obvious from Figs. 5 and 6 when the driving pin 3 in the A position, i.e. when the driving pin 3 axis is coaxial

275 with the driving shaft i axis the swinging arm 6 motion range equals to zero, the angle α = 0, and the driven shaft 8 revolutions equal zero, even when the driving shaft 1 still rotates. When the driving pin 3 is moved to the C position, i.e. when the driving pin 3 axis in the maximal distance from the driving shaft 1 axis the swinging arm 6 motion range is represented by the angle γ. When

280 the driving pin 3 is positioned in the B position, see Fig. 5, i.e. when its axis is in a position between, the A and C positions, the swinging arm 6 motion range . corresponds to the angle β. When the driving pin 3 is in the C position and the driven pin 5 is moved to the D position, i.e. when the driven pin 5 axis is at the position in the shortest distance from the driven shaft 8, the swinging

285 arm 6 motion range, represented by the angle δ, is its maximum possible value. industrial application

The transmission with a continuously variable transmission ratio is particularly suitable for applications requiring continuous change of a transmission ratio 290 starting from the driven shaft stili-stand to its full speed during simultaneous rotation of the driving shaft.