Infinitely variable transmission with lubricating wick means

Abstract

A variable speed drive mechanism in which power is transmitted from an input driving disc to an output driven disc through an intermediate member of spherical configuration. The driving and driven discs are supported with their axes of rotation at an angle and offset. The intermediate spherical member is held by gravity or other means in the trough defined between the two inclined discs. A cage member holds and linearly guides the intermediate member and a wick provides lubrication for the intermediate member. The radial position of the spherical intermediate member along the faces of the discs determines the drive ratio between the input and output shafts of the mechanism.

Description

CROSS REFERENCE TO RELATED APPLICATION

This application is broadly similar to U.S. application Ser. No. 102,393 now U.S. Pat. No. 3,698,255 of to which the present application is a continuation-in-part application broadly similar. The ball 28, being in a free rolling contact with the disc faces, may be radially displaced along the trough formed between the faces of the two discs 16 as a result of the controlled linear displacement of the cage 24, as previously mentioned, to provide the changes of the relative speed between the input shaft 34 and the output shaft 46 in such manner as to provide an infinitely variable drive ratio. The preload exerted on all the bearing supports of the rotational parts of the transmission assembly of the invention by means of the adjustable bearing retainers 36 and 53 eliminates play and backlash and takes up any elastic deformation of the discs and other components by pre-stressing such components, thus resulting in a rigid structure eliminating vibrations and erratic slippage and "digging" of the ball 28 relative to the faces of the discs 16 and 18.

The constant angular velocity couplings 38 connecting respectively the input shaft 34 to the disc 16 and the disc 18 to the output shaft 46 are a particularly important aspect of the present invention which permit the input shaft 34 and the output shaft 46 to have their axes of rotation parallel and in a single plane while permitting the angled discs 16 and 18 to have their opposed faces inclined one relative to the other and the axis of rotation of each disc to be at an angle relative to the axis of rotation of the shaft connected thereto. The constant angular velocity couplings 38 further permit the shafts 34 and 46 to be independently supported in the housing end plates 15 and 14, respectively, and the discs to be independently supported by the thrust bearings 44 and 50, respectively, while being able to transmit the preload force resulting from the axial pull exerted on the shafts 34 and 46, respectively, by the bearing retainers 36 and 53.

As shown at FIGS. 2, 4 and 5, the constant angular velocity coupling 38 between the input shaft 34 and disc 16, which is identical to the coupling 38 between the output disc 18 and shaft 46, is formed at the enlarged end portion 60 of the shaft 34, and comprises a plurality of socket-like spherical pockets 62 each adapted to receive a ball 56. The rear face of the disc 16 is provided with a cupped recessed portion 64, having in its wall a plurality of conforming socket-like pockets 66, each adapted to accept one of the balls 56. The torque transmitted from the shaft 34 to the disc 16 is thus transmitted through the intermediary of a plurality of balls 56 engaging respectively the spherical socket-like pockets 62 on the end of the shaft and the socket-like pocket 64 in the wall of the cupped portion of the disc.

As shown in particular detail at FIG. 6, both the socket-like spherical pockets 62 on the end of the shaft and the socket-like pockets 64 in the wall of the lipped portion of the disc have a short, straight, cylindrical, concave portion, shown at 66 and 68 respectively, the axis of which is inclined, in the example shown, at about 20° relatively to the axes of symmetry of the shaft and of the disc. This angle of 20° corresponds substantially to half of the angle between the axes of rotation of the disc 16 and of the shaft 34 when in normal operation as shown in FIG. 2. The straight cylindrical portion 66 of the socket-like pocket 62 on the end of the shaft and the straight cylindrical portion 68 of the socket-like pocket 64 on the disc are formed between the spherical socket-like pocket 64 and a short spherical socket-like pocket 70, and between the spherical socket-like pocket 64 and a short spherical socket-like pocket 72 formed respectively on the end of the shaft and on the wall surface of the cup-like recess 64 in the disc rear face. Each of the balls 56 travels trapped on between the socket-like pocket surfaces during a complete revolution of the angle coupling 38, and the balls generally occupy a self-established neutral position.

The angle coupling is assembled by placing the disc 16 on a horizontal plane, with the undercut cupped portion 64 directed upwardly, disposing the balls in the socket-like pockets and introducing the end 60 of the shaft into the cupped portion 64 in the disc. The whole assembly is then reversed vertically so that the disc is on the top and the shaft is on the bottom and pulled away from each other as far as they will go. The balls 56 then wedge between the socket-like pockets in both the shaft and the wall of the cupped recess in the disc and remain trapped therebetween. The preload force on the discs and associated shafts resulting from the adjustment of the bearing retainers 36 and 53 holds the diverse elements in position, and that preload results in a pull exerted respectively on the shafts 34 and 36 and is transmitted through the intermediary of the balls 56 in the couplings 38 to the discs 16 and 18 respectively.

FIG. 7 represents a torque transmitting mechanism in all respects identical to that illustrated at FIGS. 1-2, except that the thrust bearing means supporting the disc 16 from the end plate 15 and the disc 18 from the end plate 14 is substantially simplified as a result of forming a skewed integral raceway in the end plate, or, alternately and as shown, by providing an annular raceway insert 82 mounted on each of the end plates by way of bolts 84. The rear face of the disc 16 or 18 is provided with a shouldered reduced diameter portion 86 which defines the raceway depending from the disc, and a plurality of balls 88 are disposed between the two raceways 82 and 86. It is to be noted that the engagement of the balls 88 with each of the respective raceways is effected as a line contact along two circles, which have been found to be a very effective and simple way of obtaining a reliable thrust bearing.

Claims

1. A motion transmitting mechanism comprising a pair of shafts, a pair of parallel discs mounted spaced from each other with their faces mutually angularly inclined, the axes of rotation of said discs being offset by a predetermined distance, thrust bearing means supporting said discs, a ball in engagement with the surface of each of said discs, and guiding means for said ball comprising a pair of spaced parallel rod members for linearly displacing said guiding means radially relatively to the faces of said discs to vary the speed at which one disc drives the other, said guiding means for said ball comprising a wick in contact with the peripheral surface of said ball, and constant angular velocity coupling means connecting each of said shafts to a different one of said discs, wherein said constant angular velocity coupling means comprises a recessed cupped portion on each disc, a plurality of socket-like peripheral pockets formed at the end of each shaft end, a like plurality of socket-like pockets formed in the opposed surface of the cupped portion of the disc, and a ball disposed in each of said pairs pair of opposed pockets.

2. The mechanism of claim 1 wherein each of said shafts and the disc connected thereto are supported by separate bearing means, the bearing means supporting said disc are of the thrust bearing type disposed substantially at the periphery of each disc, and means are provided for placing a load on said bearings supporting said disc in a direction substantially parallel to the force exerted by said ball on said discs when in driving engagement therewith.

3. A motion transmitting mechanism comprising a driving disc and a driven disc, each having its forward face spaced one from the other and inclined at a relatively small angle relative to the other, a pair of parallel offset shafts, each coupled to one of said discs, an intermediate ball retained between the faces of said discs and in tangential contact therewith, cage means for displacing said ball along a linear path between the faces of the driving and driven discs for causing a variation in the speed of the driven disc relative to the driving disc, thrust bearing support means rotationally supporting each of said discs about the periphery thereof for maintaining said discs against axial displacement away from each other as a result of the pressure exerted thereon by said ball while in driving engagement with the faces of said discs, means for exerting a predetermined preload on said discs in a direction parallel to said pressure exerted by said ball, and constant angular velocity coupling means connecting each of said shafts to one of said discs, and coupling means comprising an end portion of said shaft having a plurality of ball retaining recesses formed therein projecting in a cupped recess about the axis of rotation of said disc on the rear face thereof, a plurality of ball retaining recesses in the wall surface of said cupped recess each of said ball retaining recesses comprising successively a spherical concave portion, a tangential cylindrical portion and a spherical concave portion, and a ball disposed partly in peripheral engagement with the surface of corresponding ball retaining recesses.

4. The mechanism of claim 3 wherein said intermediate ball is disposed in a cage, said cage being supported and guided for linear displacement between said discs by means of a pair of parallel support and guiding rods.

5. The mechanism of claim 4 wherein a pair of roller elements are mounted on said cage for supporting said intermediate ball therebetween.

6. The mechanism of claim 5 wherein a wick is mounted on said cage, said wick having one end in contact with the surface of said intermediate ball and another end dipping in a source of lubricant for continuously wetting the surface of said intermediate ball with a film of said lubricant.