GB1594969A - Transmission device - Google Patents

Description

(54) TRANSMISSION DEVICE (71) We, VADETEC S.A., a Swiss body corporate of 7, Chemin de Charmettes, B.P.

3453, 1002 Lausanne, Switzerland, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: This invention relates to improvements in variable speed transmission devices and more particularly, it concerns an improved transmission device of the type in which torque is transmitted by rolling frictional engagement at two points of contact between a pair of first and second elements having respective rolling surfaces disposed about intersecting first and second axes, the second element preferably being capable of nutation so that the second axis moves in a biconical path about the first axis.

In our British Patent 1479765 and for example our Applications Serial Nos. 1564824 and 1564825, there are disclosed several embodiments of such a transmission, or torque variator, in which a gyroscopic couple is depolyed at the points of rolling friction contact between the first element and the second element. In certain embodiments, the gyroscopic couple is used to develop the normal force necessary to retain the rolling surfaces of the respective first and second elements in frictional engagement with each other whereas in other embodiments, such as those described in the above-mentioned Applications the normal force required for frictional engagement is developed by mechanical means opposed by inertial forces including the gyroscopic couple to minimize the load-supporting requirements of bearings used in the transmission. While both forms of the transmission, as thus characterized, have demonstrated great potential from the standpoint of providing an exceedingly well-balanced, variable speed torque transmission requiring a small number of easily machined components, the latter form in which the inertial forces oppose a inechanically induced normal friction force couple has not shown particular promise because of the facility it provides for reducing both size and friction losses in bearings used to support the respective first and second elements.

Variation in angular velocity between an input shaft and an output shaft of the transmission disclosed in the above mentioned Applications is effected by providing the rolling friction surfaces coupled to one of the shafts on a pair of generally conical members each having an apex half-angle approximately the same as the angle between the intersecting axes of the first and second elements. The conical surfaces converge from'the point of first and second element axes intersection and are movable in the direction of convergence into engagement with annular rings carried by the second elements. The rings also are axially adjustable on the second element so as to engage the conical members at varying radial distances from the axis of the conical members. Inasmuch as the annular rings are of a fixed radius, the speed ratio of input and output shafts connected to the respective first and second elements will vary with the radius of the conical members at the point of rolling friction engagement.

Although various control devices are disclosed in the aforementioned Applications for controlling the axial positioning of the annular rings carried by one or the other of the first and second elements, the annular rings as well as the control mechanism for their axial adjustment represent a relatively complicated control organization in the overall basically simple transmission. Accordingly, there is room for improvement principally in the control mechanism necessary to the attainment of the variable transmission speed ratios.

In accordance with the present invention there is provided a transmission device comprising a frame, a first element having a first axis fixed relative to the frame, and a second element having a second axis intersecting the first axis, said first element having a pair of rolling surfaces disposed about said first axis one each side of the point of intersection of said axes, said second element having a pair of rolling surfaces disposed about said second axis one each side of the point of intersection of said axes, biasing means being provided for urging the respective rolling surfaces of the first and second elements into relative rolling engagement at points located on each side of a plane passing through the point of intersection of said axes, wherein the first element comprises two members each carrying a respective rolling surface and being movable with respect to each other along said first axis, and the second element is carried by means selectively controllable to vary the angle of intersection of said axes, the respective generatrices of the rolling surfaces of said first and second elements being such that the ratio of the radus of the loci of the points of contact between said rolling surfaces with respect to said first axis, to the radius of said loci with respect to said second axis, can be altered with variation of the angle of intersection of said axes and the axial positions of the two members of said first element.

Preferably the second axis is capable of moving biconically about the first axis.

In a preferred embodiment, the rolling surfaces on one of the elements are established by an interior cylindrical surface positioned about a pair of cone-like members which comprise the other of the elements and are supported for rotation and for axial movement toward and away from the point of axes intersection, each of the cone-like members having exterior surfaces of revolution converging from the point of axes intersection and defined by curved, preferably part circular generatrices. To enable both of the elements to be supported by simple radial bearings such that both elements are directly or'positively supported on their respective axes in relation to the transmission frame, the radii of generatrix curvature is long and related geometrically to variations in the surface radius defined by the generatrix and to variations in the angle of axes intersection.

Preferably the second element is supported by a third element journalled for rotation about the first axis. In a preferred embodiment third element extends within and through the rolling surfaces of the second element, is cut away to enable frictional contact of the rolling surfaces on the first element with those of the second, and carries at opposite ends cooperating adjustable bearing assemblies operated by hydraulic piston/cylinder units to vary the angle of axes intersection between the first and second elements. The nutating second element is grounded to a frame in a manner to prevent rotation thereof about the second axis by an unique double U-joint system positioned centrally and thus symmetrically with respect to the second axis. A fluid control system capable of operating the piston/cylinder units to adjust the respective angular positions of the second element is effectively provided by an externally controlled pump system carried by the third element of the transmission.

In an alternative embodiment, the angle of axes intersection is adjusted by an eccentric sleeve supporting the second element from the third element. Variation in the angle of axes intersection is accomplished by a fluid control system capable of angularly adjusting the respective positions of the eccentric sleeve and the third element by an externally controlled, transmission carried pump.

For a given input speed, the rotational speed of the transmission output, preferably an output shaft, may be varied continuously through the range of radii defined by the rolling surfaces on the cone-like members. Additionally, a gear-type transmission may be connected to the cone-like members to provide multiple increments of such continuously variable speed ranges as well as a neutral to reverse the direction of output shaft rotation.

Also, the transmission may be releasably coupled to a source of input torque by a clutch.

Some embodiments of the invention will now be described by way of example and with reference to the accompanying drawings, in which: Figure 1 is a longitudinal cross-section through a transmission in accordance with the present invention; Figure 2 is a cross-section illustrating a rotational component incorporated in the transmission of Figure 1; Figure 3 is a fragmentary cross-section on line 3-3 of Figure 2; Figure 4-4 is a fragmentary cross-section on line 4-4 of Figure 2; Figure 5 is a plan view illustrating a half-section of the component illustrated in Figure 2; Figure 6 is a fragmentary perspective view illustrating the element shown in Figure 5; Figure 7 is a fragmentary cross-section illustrating an alternative embodiment of bearing assembly employed in the transmission; Figure 8 is a side elevation illustrating one of the components of the bearing assembly shown in Figure 7; Figure 9 is a fragmentary cross-section on line 9-9 of Figure 1; Figure 10 is an enlarged fragmentary cross-section of components illustrated in Figure 9; Figure 11 is an end elevation as shown on line 11-11 of Figure 10; Figure 12 is an enlarged fragmentary cross-section on line 12-12 of Figure 3; Figure 13 is a fragmentary cross-section on line 13-13 of Figure 1; Figure 14 is a cross-section on line 14-14 of Figure 13; Figure 15 is a longitudinal cross-section through an alternative embodiment of a transmission in accordance with the present invention; Figure 16 is a fragmentary, transverse cross-section through Figure 15; and Figure 17 is an enlarged cutaway perspective view illustrating the eccentric control sleeve of the transmission shown in Figure 15.

A preferred embodiment of the overall transmission in accordance with the present invention is shown in Figure 1 of the drawings to include an enclosed frame or housing 10 having at one end a peripheral mounting flange 12 adapted to be secured directly to the frame or block of an engine or other suitable source of driving torque represented by the phantom line illustration to the left of Figure 1. At its opposite end, the frame 10 is provided with an inwardly directed flange 14 delineating one end of a gear box generally designated by the reference numeral 16. An intermediate, inwardly directed flange 18 on the housing 10 separates the opposite end of the gear box 16 from a torque variator 20. As will be described in more detail below, the torque variator is connected in part to the frame 10 by way of a further inwardly directed flange 22.

Torque input to the transmission is preferably through a centrifugal clutch generally designated by the reference numeral 24 and located adjacent the peripheral mounting boss 12 on the frame. The clutch 24 is, in itself, conventional and as such includes a drive plate 26 having a central recess 28 through which torque transmitting pins 30 project for engagement with and support by an input shaft (not shown) appropriately journalled in the power source to which the transmission is connected in practice. The drive plate 26 carries a fixed annular friction pad 32 on one side of a driven disc 34. The disc 34 is adapted to be seized between the fixed friction pad 32 and an annular clamping pad 36 by an annular piston 38 movable by hydraulic fluid or oil supplied from an annular chamber 40, outwardly through a port 42 and under the control of a sensor 44. Thus, with no rotation of the drive plate 26, oil is fed past the sensor 44 and the disc 34 of the clutch is in a disengaged condition. As the drive plate 26 undergoes rotation, the oil in the port 42 will be moved outwardly by centrifugal force, fed against the annular piston 38 until the output disc 34 is engaged by the friction pads 32 and 36.

Extending longitudinally of the transmission on a first or primary transmission axis 46 are a pair of concentric torque transmitting shafts 48 and 50. The central shaft 50 is keyed directly to the clutch drive plate 26 and may be coupled at its end opposite from the clutch to auxiliary engine components (not shown) or other means to be connected in a direct drive relationship with the input torque to the transmission by way of the drive plate 26.

The hollow shaft 48 is rotatable independently of the central shaft 50 and supported in the frame 10 on the axis 46 by bearings 52, 54 and 56. As will be seen from the description to follow below, the hollow shaft 48 in the disclosed embodiment is the output of the torque variator 20 and the input to the gear box 16. Torque output from the overall transmission is by way of a countershaft 58 coupled to the hollow shaft 48 through the gear box 16.

As shown in Figure 1, the gear box 16 includes a pair of pinion gears 59 and 60 keyed for rotation with the hollow shaft 48 and in engagement at all times with pinion gears 62 and 64 which are freely rotatable on the output countershaft 58. It will be noted that although the teeth of the respective gear sets 59, 62 and 60, 64 are shown out of engagement, these gears are engaged by reversing idler pinions (not shown) so that both gears of each set rotate in the same direction. A coupling gear 66 is splined for rotation with the counter shaft 58 and is slidable axially thereon. The gears 62, 66 and 64 are provided with interengaging axial sets of teeth 68 and 70 so that the gear 66 may be maintained in an intermediate position as shown in Figure 1 or in positions of coupled engagement with either of the gears 62 and 64.

Since the gears 62 and 64 will be driven by the gears 59 and 60 in the same direction as the hollow shaft 48, a first forward gear ratio may be effected by engagement of the coupling gear 66 with the gear 62. In this gear ratio, torque transmission from the shaft 48 will be from the gear 59 through an idler gear (not shown) to the gear 62 and the coupling gear 66 to the output counter shaft 58. A second forward gear ratio involves merely shifting the coupling gear 66 into engagement with the gear 64 so that the train will be through the gear 60 'and another idler gear (not shown) to the gear 64, through the coupling gear 66 to the shaft 58. A reversal of the counter shaft 58 with respect to the hollow shaft 48 is effected by the intermediate position shown. In this condition, the coupling gear 66 is driven directly by a gear 72, normally rotatable freely on the shaft 48, but driven by engagement by axial teeth 74 with the gear 59.

In accordance with the invention, input torque operable to drive the clutch 24 at an angular velocity a" is transmitted to the gear box 16 by rotation of the hollow shaft 48 at an angular velocity as a result of the operation of the torque variator 20 through an infinite variation of speed ratios o /a . Although the several structural components of the torque variator which contribute to this operation will be described in detail below, an understanding of this basic operation may be gained by noting that the torque variator 20 is comprised three assemblies which are movable as units or elements; namely, a first rotational element 78 concentric with the first axis 46, a second nutatable element 80 symmetrically disposed about a second axis 82 inclined with respect to the first axis 46 by an angle a and intersecting the first axis at a point of axes intersection S, and a third element 84 coaxial with and rotatable on the first axis 46. The third element 84 functions in the manner of a support by which the angular disposition of the second axis 82 relative to the first axis 46 is maintained.

As may be observed in Figure 1, the first element 78 of the torque variator 20 is established by a pair of cone-like members 86 and 88, splined for direct rotation with the hollow shaft 48 and slidable axially thereon in symmetry toward and away from the point S.

The members 86 and 88 are biased away from each other in the disclosed embodiment by compression springs 90 through other suitable biasing means such as a hydraulic system or a system of opposed helical splines may be employed to this end. Each of the cone-like members 86 and 88 is identically shaped to define an outer rolling traction surface 92 having a variable radius Rw with respect to the first axis 46. Also, it will be noted that the generatrix of each of the surfaces 92 is a curve having a long radius Rc which is related to minimum () and maximum (t) values of the radius Rw and the angle a under the equation:

The second or nutating element 80 of the torque variator is essentially a tube-like structure having concentric journal and rolling or traction surfaces of revolution about the second axis 82, such surfaces being designated respectively by the reference numerals 94 and 95 in Figure 1. These surfaces are duplicated on opposite sides of the point of axes intersection S. Also it is to be noted that the rolling or traction surfaces or revolution 95 are of the same radius Rb with respect to the axis 82 and that the surfaces 95 engage the surfaces 92 of the cone-like members 86 and 88 at two points of contact P1 and P2 spaced equally and oppositely from the point S.

The journal surfaces 94 on the second element 80 are rotatably engaged by bearing assemblies 96 and 98 carried as a unit with the third or support element 84 in a manner which will be described below. Also, a system of U-joints generally designated by the reference numeral 100, extend from the flange 22 on the frame 10 to the second element 80 to restrain the latter against rotation on the second axis 82 without in any way inhibiting nutation of the member 80 in a manner such that the second axis 82 may travel in a biconical orbit or path about the first axis 46 in symmetry with the point of axes intersection S.

In the disclosed embodiment, the third element 84 serves to drive the torque variator 20 and as such is coupled for rotation with the output disc 34 of the clutch 24 by exterior splines 102. Also it will be seen in Figure 1 that the element 84 is supported for rotation at one end thereof in the vicinity of the splines 102 independently of the shaft 48 by the previously mentioned bearing 56 and also independently of the drive plate 26 of the clutch by bearing 104. At its opposite end, the member 84 is journalled for rotation on the shaft 48 by a bearing 106. Also, a central bearing sleeve 108 is provided between the shaft 48 and a connecting ring or collar 110 forming a part of the element 84. An understanding of the manner in which torque is transmitted from the third element 84 to the nutating second element 80 may be gained by reference to Figures 2-6 of the drawings in which the structure of the element 84 is fully illustrated.

As shown in Figure 2, the element 84 is constituted by a pair of generally similar longitudinal half-sections 112 and 114 secured in an end-for-end relationship against opposite faces of the connecting ring or collar 110 by a series of axial screw bolts 116 or other equivalent means. Each of the sections extends from the collar 110 as a sleeve-like structure to journal bosses 118. An intermediate portion of each section 112 and 114 is cut away to provide diammetrically opposite openings 120 and 122 in the assembled element. It will be appreciated that the openings 120 and 122 expose the cone-like members 86 and 88 so that the rolling traction surfaces 92 thereon are presented through the member 84.

Each of the journal bosses 118 is similarly shaped to define an integral yoke portions 124 shown most clearly in Figures 5 and 6 to include a pair of outwardly spaced longitudinally extending leg plates 126 each having an inclined bolting surface 128. A cylinder head bracket 130 is secured by bolts 132 to both leg plates 126 of each yoke 124. Each of the brackets 130 defines an inwardly facing cylinder 134 to which oil or other suitable hydraulic fluid may be fed by passageway 136 formed in the bracket 130 and communicating with passageways 138 and 140 in each yoke 124 (Figure 3).

In the embodiment of Figures 1-6, the bearing assemblies 96 and 98 each include a series of rollers to engage the journal surfaces 94 on the nutatable second element 80 and which are supported by an outer race member 142. The outer race member 142 is formed with a piston 144 adapted to be received in the cylinder 134 and is further provided with external flats 146 slidable on the inner surfaces of the leg plates 126 of each yoke 124. It will be noted that the pistons 144 of the outer races 142 in the respective bearing assemblies 96 and 98 at opposite ends of the member 84 are diametrically opposed. In light of this arrangement, the tube-like nutating member 80 may be adjustably tilted about the point of axes intersection S by simultaneous introduction of oil to or discharge of oil from the cylinders 134 of each of the bearing assemblies 96 and 98. Such a tilting adjustment will, of course, result in an adjustment of the second axis 82 to vary the angle a between minimum (a | ) and maximum (a 1 ) values. The effect of such a variation in the angle a results in simultaneous shifting of the contact points P1 and P2 toward or away from the point of axes intersection S. As a result of this movement of the contact points, the radius Rw of the surfaces 92 on the cone-like members 86 and 88 will vary from a minimum value for a 1 to a maximum value for a > , . Since the radius Rb of the rolling traction surfaces 95 on the nutating member 80 remains constant, the ratio Rb/RW or p will vary directly with the angle a.

The operation of the torque variator 20 to transmit torque rotatably driving the third element 84 at a velocity a , to output torque at infinitely varying speed ratios in the hollow shaft 48 at velocities oO may now be appreciated. In particular, rotation of the member 84 and correspondingly, coordinated orbital movement of the outer races 142 of the two bearing assemblies 96 and 98, will cause the member 80 to move in a nutational manner so that the axis 82 thereof is carried in a biconical path about the first axis 46 with the surfaces 95 and 92 in friction transmitting engagement with each other at the two points P1 and P2.

Since the member 80 is prevented from rotation on the axis 82 by the U-joint system 100, the cone-like members 86 and 88 as well as the shaft 48 to which they are splined will be driven at the velocity o" in accordance with the equation o) = a"(l - p). Since the radius Rb is always greater than the radius Rw, the function p will always be in excess of 1. As a result, is a directional reversal of cr".

With reference again to Figures 2-6 of the drawings, it will be noted that the bolting surfaces 128 on the leg plates 126 of each of the yokes 124 is inclined so that the axis of each cylinder 134 is at an angle with respect to the axis 46 of the element 84. This angle is selected to be approximately one-half the value of variation in the angle a or midway between a and a S . Also, the pistons 144 are constructed to facilitate a degree of axial misalignment with the axis of the cylinders 134 to accomodate variations in the angle a.

In Figures 7 and 8 of the drawings, an alternative form of the bearing assemblies 96 and 98 is shown with parts corresponding to those of the assemblies 96 and 98 being designated by like reference numerals but primed. Hence, in the alternative embodiment of Figures 7 and 8, the piston 144' is provided on a bearing body 142' having external flats 146' for sliding movement with respect to the yoke 124 in the same manner as the outer race 142 of the bearing assemblies 96 and 98 previously described. In this instance, however, the inner surface of the body 142' is provided with a semi-cylindrical bearing surface 148 engagable directly with the journal surfaces 94 on the tube-like nutating member 80. The surface 148 is provided with oil slots 150 to provide a hydrostatic bearing between the body 142' and the journal surfaces 94 on the nutating member. The piston 144' is modified to include a sliding seal nipple 152 receivable in a central chamber 154 to which oil is supplied in the same manner as it is to the cylinder 134' for actuating the piston 144'. The oil slots 150 are in communication with the nipple 152 by ports 156.

Although the alternative embodiment of the bearings illustrated in Figure 7 and 8 functions in all respects like the bearing assemblies 96 and 98 in the embodiment of Figures 106, the alternative embodiment provides improved operation in at least some applications of the overall transmission by reducing friction between the bearings and the tube-like nutating member 80. In particular, and assuming friction losses of a hydrostatic bearing to be comparable with that of a roller bearing, friction is reduced as a result of minimizing the surface contact in the bearing.

In Figures 9-11 of the drawings, the U-joint system 100 by which the nutating member 80 is interconnected with the frame 10 to prevent rotation of the member 80 about the axis 82 is more clearly shown to include an exterior mounting flange or ring 158 having a plurality of bolt holes 160 for securement to the inwardly directed flange 22 of the frame 10 as shown in Figure 1 of the drawings. In Figure 9, a pair of mutually perpendicular transverse pivot axes X-X and Y-Y are shown and lie in a plane 161 intersecting the point of axes intersection S. The system disclosed may be characterized as a double U-joint and as such includes a first outer ring 162 pivoted on the axis Y-Y by trunnion journals 163 in the mounting ring 158 and a second inner ring 164 pivoted from the outer ring 162 on the axis X-X by a pair of trunnion sleeves 166. The nutating member 80 is pivotally supported from the inner ring 164 on the axis Y-Y by trunnions 168.

Although the use of a single U-joint (a system in which only one of the rings 162, or 164 is used with trunnion support of the member 80 from a single ring on one of the perpendicular transverse axes and the ring pivoted from the mounting ring 158 on the other of such axes) would effect a universal grounding of the member 80 with the frame, the angular disposition of the tube 80 in the context of rotation about the axis 82 would not be constant as will be appreciated by those familiar with the art relating to U-joints. While this condition is corrected by the use of a double U-joint, the common pivot point S of both rings 162 and 164 is best practiced where the relative movement of both rings 162 and 164 is controlled.

To this end, a pair of swivel arms 170 are disposed on the axis X-X. As shown most clearly in Figure 10 of the drawings, the arm 170 is provided with spherical bearing surfaces 172, 174 and 176 intermediSte its length and at opposite ends respectively. The spherical bearing 174 is received in a socket 178 carried by an externally circular sleeve 180, in turn received in an oblong slot 182 in the nutating member 80. The sleeve 180 is, therefore, capable of sliding movement in the slot 182 and also with a measure of freedom in a plan perpendicular to the axis 82 of the member 80 or the plane 161. The intermediate spherical bearing 172 is pivoted in a socket 184 carried directly by the trunnion sleeve 166 by which the inner and outer rings 162 and 164 are pivotally interconnected on the axis X-X. The sleeve 184 is fixed against axial movement in the trunnion sleeve 166. The spherical bearing 176 is pivoted in a socket 186 carried by a sleeve 188 for axial movement relative to the mounting ring 158.

As a result of this organization of the control arms 170, the member 80 is free to undergo nutating movement relative to the frame 10 and maintain a truly constant non-rotatable orientation on the axis 82 while the relative angular orientation of the rings 162 and 164 is controlled. The U-joint system is, therefore, prevented from locking as might occur if both wings were completely free to pivot on the respective trunnion axes X-X and Y-Y.

Reference is now made to Figures 1-4 and 12-14 of the drawings which illustrate a fluid system for both lubricating the transmission and controlling the actuation of the piston 144 to change the angle a at which the axes 46 and 82 intersect. As shown in Figure 1, the inwardly directed flange 18 on the frame 10 supports a hub 188 which supports the bearing 54 and in addition, defines an annular chamber 190 to which oil is fed by a passageway 192 communicating with an external supply of oil represented by a hose fitting 194. The chamber 190 communicates through the hollow shaft 48 by ports 196 so that oil may pass from the chamber 190 through the annulus extending along the complete length of the concentric shafts 48 and 50. The shaft 48 is further provided with radial ports such as a port 198 through which oil passing between the shafts 50 and 48 will be thrown outwardly by centrifugal force alone or combined with system pressure under which the oil is passed to the annular chamber 190. Although various additional lubrication passages are illustrated in Figure 1 of the drawings, it is believed that further description of these passages is unnecessary to a complete understanding of the present invention.

The bea the port 204 with a dump valve 226. Thus, it will be appreciated that when the ball check 224 is moved to an unseated position, both discharge from the chamber 212 and oil from the passageway 204 may be passed directly through the dump valve 226.

The manner in which the pump and dump valve arrangement illustrated in Figure 12 are actuated and controlled may be seen by reference to Figures 1, 13 and 14 of the drawings.

Both the dump valve rod 222 and the plunger 210 support rollers in a position to engage an annular track 230 pivotally supported from the hub 188 by pintels 232. An arm 234 extends from the ring defining the track 230 on the side thereof opposite from the pintels 232 and is engaged by a control linkage 236 for pivotal movement between three positions depicted in Figure 14 of the drawings. Thus, when the track 230 is maintained in a plane truly perpendicular to the axis 46, no pumping action will occur nor will the dump valve 224 be opened. Accordingly, the condition of the pistons 144 will be stable in this position of the track 230. Pivotal inclination of the track 230 to the position represented by the line A in Figure 14 will result in reciprocation of the plunger to pump oil into the cylinders 134. The dump plunger 222 will be retracted from the dump valve 224 in this position of the track 230. If the track is pivoted to the position B, however, the plunger 222 will unseat the dump valve 224 causing fluid to be exhausted from the cylinders 134 and correspndingly bring about movement of the pistons in the other directions.

In Figures 15 and 16 of the drawings, an alternative embodiment of the transmission in accordance with the present invention is shown to include a frame 310 supporting a first element, generally designated by the reference numeral 312, for rotation on a longitudinal axis 314. A second element 316 having symmetry about a longitudinal axis 318 is supported from the frame 310 by a support 320 journalled for rotation about the axis 314 by bearings 322 and 324. As shown, the support includes an external cylindrical shell 326 and one end of the support extends integrally as a sleeve portion 328 to be supported by the bearings 324 and to extend beyond the frame 310. It will be noted that although the bearings 324 are not directly supported by the transmission frame 310, the frame 310 in use will be rigidly associated with an engine frame 311 by which such support for the bearings 324 will be provided.

The first element 312 includes a hollow shaft 332 supported from the frame 310 by bearings 334 and 336 for rotation on the first axis 314. The shaft 332, in turn, supports a pair of cone-like members 338 and 340 which are fixed for rotation with the shaft 332 by splines 341 but movable axially thereon in symmetry toward- and away from the point S under an axial force applied by a helical compression spring 342. While the magnitude of the mechanical force developed by the helical spring 342 will be essentially constant, other means for developing a variable axial force are contemplated, such as a fluid system or a system of helical ramps and the like.

The second element 316, in the embodiment of Figures 15-17, is an essentially cylindrical member 344 having a cylindrical interior surface 346 of constant radius R1 on the axis 318 throughout its length. The member 344 is supported for rotation by bearings 348 and 350 with respect to an eccentric sleeve 352 in turn supported by bearings 354 and 356 providing rotation with respect to the support member 320. Although embodiments of the invention are contemplated in which the cylindrical member 344 constituting the second element 316 may be freely rotatably about the axis 318 and relative to the frame 310, in the disclosed embodiment, the cylindrical member 344 is retained against rotation on the axis 318 with respect to the frame 310 by an arm 358 having one end 360 non-rotatably fixed to the cylindrical member 344 and its other end 362 secured against rotation with respect to the frame 310 by an Oldham joint 364.

The eccentric sleeve 352 is shaped such that an external cylindrical journal defined by the bearings 354 and 356 is concentric with an axis 366 whereas the inner cylindrical journal of the sleeve, defined by the bearings 348 and 350, is concentric with an axis 368. While the angular relationship of the axes 366 and 368 may vary from the angle a, the axes 366 and 368 intersect each other in the assembled transmission at the point of axes intersection S. As a result of this construction of the sleeve 352 and it position between the support member 320 and the cylinder 344, relative rotation of the sleeve 352 and the support 320 will operate to vary the angle a between the first and second axes 314 and 318. To control this variation in the angle a, the exterior surface of the sleeve 352 defines with the interior surface of the support member 320 an annular chamber 370 spanned by a pair of vane-like strips 372 and 374. As shown in Figures 15 ansd 16, the vane 372 is secured by suitable means such as screws 375 to the eccentric sleeve 352 whereas the vane-like strip 374 is similarly secured to the support 320.

Due to the transmission of drive torque between the support 320 and the cylinder 344 across the chamber 370, relative rotation of the eccentric sleeve and the support will be under a drive torque bias in one direction. Such a drive torque bias will be opposed by control fluid pressure in the chamber 370 acting to effect relative rotation of the sleeve 352 and the support 320 in the other direction. Control fluid under pressure is fed to the annular chamber and discharged therefrom through a passageway 376 operatively connected to a pump 379 mounted to the exterior of the support 320.

The operation of the pump 379 is the same as that disclosed with respect to the embodiment of Figures 1-14. In other words, fluid is pumped into or withdrawn from the passageway 376 to adjustably rotate the sleeve 352 and adjust the angle a. The pump 379 has a plunger controlled by a ring 418, pivotably adjustable by a control unit 422. In other respects, the embodiment of Figures 15-17 is similar to the first described embodiment.

Thus it will be appreciated that as a result of the present invention a highly effective torque transmitting system is provided.

At least in the preferred embodiments, there is provided a transmission in which a variation in transmission speed ratio is effected by variation in the angle of axes intersection between a rotatable element and a nutating element in frictional engagement with each other at two points of contact spaced equally from the point of axes intersection. All components in the preferred embodiments are positively supported and controlled without need for complex supporting or control components. The transmission in the preferred embodiments may be easily coupled to a source of input torque by a releasable clutch, and may have an incremental output speed variation superimposed on the continuous speed ratio variation effected by the torque variator thereof.

WHAT WE CLAIM IS: 1. A transmission device comprising a frame, a first element having a first axis fixed relative to the frame, and a second element having a second axis intersecting the first axis, said first element having a pair of rolling surfaces disposed about said first axis one each side of the point of intersection of said axes, said second element having a pair of rolling surfaces disposed about said second axis one each side of the point of intersection of said axes, biasing means being provided for urging the respective rolling surfaces of the first and second elements into relative rolling engagement at points located on each side of a plane passing through the point of intersection of said axes, wherein the first element comprises two members each carrying a respective rolling surface and being movable with respect.to each other along said first axis, and the second element is carried by means selectively controllable to vary the angle of intersection of said axes, the respective generatrices of the rolling surfaces of said first and second elements being such that the ratio of the radius of the loci of the points of contact between said rolling surfaces with respect to said first axis, to the radius of said loci with respect to said second axis, can be altered with variation of the angle of intersection of said axes and the axial positions of the two members of said first element.

2. A device as claimed in claim 1 wherein the rolling surfaces of the second element are closed interior surfaces of revolution and the rolling surfaces of the first element are continuous exterior surfaces of revolution.

3. A device as claimed in claim 2 wherein the rolling surfaces of the second element are interior cylindrical surfaces and the rolling surfaces of the first element are defined by oppositely inclined curved generatrices.

4. A device as claimed in claim 2 or 3 wherein the rolling surfaces of the first element are defined by oppositely inclined arcuate generatrices having a radius of curvature (Rc) related to minimum ( C ) and maximum ( t ) values of the radius (Rw) of the rolling surfaces of the second element and the angle (a) of intersection of the first and second axes, in accordance with the equation:

5. A device as claimed in any preceding claim, wherein the second axis is adapted to more biconically about the first axis and the second element is grounded to the frame to prevent rotation of the second element about the second axis.

6. A device as claimed in claim 5 wherein an U-joint system interconnects the second element and the frame to prevent rotation of the second element about the second axis.

7. A device as claimed in claim 6 wherein said U-joint system comprises inner and outer concentric rings pivotally interconnected to each other on one transverse axis, and pivotally connected to the frame and to the second element on another transverse axis perpendicular to said one transverse axis, and control means for governing relative motion of said rings, the frame and the second element.

8. A device as claimed in claim 7 wherein said U-joint system comprises a hollow trunnion for pivotally interconnecting said inner and outer rings on said one transverse axis,

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (22)

**WARNING** start of CLMS field may overlap end of DESC **. and the support 320 in the other direction. Control fluid under pressure is fed to the annular chamber and discharged therefrom through a passageway 376 operatively connected to a pump 379 mounted to the exterior of the support 320. The operation of the pump 379 is the same as that disclosed with respect to the embodiment of Figures 1-14. In other words, fluid is pumped into or withdrawn from the passageway 376 to adjustably rotate the sleeve 352 and adjust the angle a. The pump 379 has a plunger controlled by a ring 418, pivotably adjustable by a control unit 422. In other respects, the embodiment of Figures 15-17 is similar to the first described embodiment. Thus it will be appreciated that as a result of the present invention a highly effective torque transmitting system is provided. At least in the preferred embodiments, there is provided a transmission in which a variation in transmission speed ratio is effected by variation in the angle of axes intersection between a rotatable element and a nutating element in frictional engagement with each other at two points of contact spaced equally from the point of axes intersection. All components in the preferred embodiments are positively supported and controlled without need for complex supporting or control components. The transmission in the preferred embodiments may be easily coupled to a source of input torque by a releasable clutch, and may have an incremental output speed variation superimposed on the continuous speed ratio variation effected by the torque variator thereof. WHAT WE CLAIM IS:

1. A transmission device comprising a frame, a first element having a first axis fixed relative to the frame, and a second element having a second axis intersecting the first axis, said first element having a pair of rolling surfaces disposed about said first axis one each side of the point of intersection of said axes, said second element having a pair of rolling surfaces disposed about said second axis one each side of the point of intersection of said axes, biasing means being provided for urging the respective rolling surfaces of the first and second elements into relative rolling engagement at points located on each side of a plane passing through the point of intersection of said axes, wherein the first element comprises two members each carrying a respective rolling surface and being movable with respect.to each other along said first axis, and the second element is carried by means selectively controllable to vary the angle of intersection of said axes, the respective generatrices of the rolling surfaces of said first and second elements being such that the ratio of the radius of the loci of the points of contact between said rolling surfaces with respect to said first axis, to the radius of said loci with respect to said second axis, can be altered with variation of the angle of intersection of said axes and the axial positions of the two members of said first element.

2. A device as claimed in claim 1 wherein the rolling surfaces of the second element are closed interior surfaces of revolution and the rolling surfaces of the first element are continuous exterior surfaces of revolution.

3. A device as claimed in claim 2 wherein the rolling surfaces of the second element are interior cylindrical surfaces and the rolling surfaces of the first element are defined by oppositely inclined curved generatrices.

4. A device as claimed in claim 2 or 3 wherein the rolling surfaces of the first element are defined by oppositely inclined arcuate generatrices having a radius of curvature (Rc) related to minimum ( C ) and maximum ( t ) values of the radius (Rw) of the rolling surfaces of the second element and the angle (a) of intersection of the first and second axes, in accordance with the equation:

5. A device as claimed in any preceding claim, wherein the second axis is adapted to more biconically about the first axis and the second element is grounded to the frame to prevent rotation of the second element about the second axis.

6. A device as claimed in claim 5 wherein an U-joint system interconnects the second element and the frame to prevent rotation of the second element about the second axis.

7. A device as claimed in claim 6 wherein said U-joint system comprises inner and outer concentric rings pivotally interconnected to each other on one transverse axis, and pivotally connected to the frame and to the second element on another transverse axis perpendicular to said one transverse axis, and control means for governing relative motion of said rings, the frame and the second element.

8. A device as claimed in claim 7 wherein said U-joint system comprises a hollow trunnion for pivotally interconnecting said inner and outer rings on said one transverse axis,

and wherein said control means comprises at least one arm having an intermediate fulcrum within said hollow trunnion and a pair of end fulcrums pivotally and slidably connected with the frame and the second element respectively.

9. A device as claimed in claim 5 wherein ithe second element is grounded to the frame by an arm having one end rigidly connected to the second element and the other end pivotally and slidably connected to the frame.

10. A device as claimed in any preceding claim wherein means for varying the angle of intersection of said axes comprises diametrically opposed, radially acting, fluid actuable piston/cylinder units spaced in opposite axial directions from the point of the intersection of said axes.

11. A device as claimed in any of claims 1 to 9, wherein means for varying the angle of intersection of said axes comprises a rotatable sleeve having mutually inclined inner and outer cylindrical bearing surfaces. said inner bearing surfaces estalishing said second axis.

12. A device as claimed in claim 11 including fluid actuable means for adjustably rotating said sleeve.

13. A device as claimed in any preceding claim in which the second axis is capable of moving biconically about the first axis and wherein the second element is supported by journals on a third element arranged for rotation about the first axis.

14. A device as claimed in claim 13, wherein the third element comprises a sleeve-like member extending between the rolling surfaces of the first and second elements and having openings to enable the relative rolling engagement of the respective rolling surfaces.

15. A device as claimed in claim 13 or 14. and claim 10 wherein the journals of the third element are located at opposite ends of the second element and are movable in diametrically opposite directions relative to the third element, by means of the piston/cylinder units, for positioning the journals symmetrically about the point of intersection of said axes.

16. A device as claimed in claims 14 and 15 wherein said piston/cylinder devices each comprise a cylinder carried by said sleeve-like member and a piston operable in said cylinder and fixed to the respective journal.

17. A device as claimed in any of claims 13 to 16 wherein the second element has exterior journal surfaces engaged by the journals of the third element.

18. A device as claimed in claim 17 wherein the journals ofvthe third element each comprise an anti-friction bearing circumscribing the journal surfaces of the second element.

19. A device as claimed in claim 18 wherein the journals comprise hydrostatic bearings having semi-cylindrical bearing surfaces to engage the journal surfaces of the second elements at diametrically opposite sides thereof.

20. A device as claimed in claim 13 and any of claims 10, 11. 12, 15 or 16, including a fluid supply pump carried by said third element.

21. A device as claimed in claim 20, including means on the exterior of the flame for controlling said pump.

22. A transmission device, substantially as hereinbefore described with reference to Figures 1 to 14, or 15 to 17, of the accompanying drawings.