JP6876521B2 - Forward / backward switching mechanism of continuously variable transmission - Google Patents

Description

The present invention is a planetary gear mechanism including an input element connected to an output shaft of a continuously variable transmission, an output element connected to a differential gear, and a fixed element that is rotatably fitted to the outer periphery of the output shaft. The present invention relates to a forward / backward switching mechanism of a continuously variable transmission including a dog clutch capable of selectively coupling the fixed element to the input element or a transmission case.

A forward / backward switching mechanism including a planetary gear mechanism is placed on the downstream side of a crank-type continuously variable transmission that can shift the rotation of the input shaft and transmit it to the output shaft, and the forward / backward switching mechanism keeps the rotation of the output shaft differential. It is known from the following Patent Document 1 that the drive range is established by transmitting to the gear and the reverse rotation of the output shaft is transmitted to the differential gear to establish the reverse range.

WO2014 / 188823

By the way, since the conventional one includes two dog clutches in which the forward / backward switching mechanism is juxtaposed in the axial direction of the output shaft, not only the size of the continuously variable transmission including the forward / backward switching mechanism is increased, but also the size of the continuously variable transmission is increased. There is a problem that the operating load of the shift sleeve increases due to the large frictional resistance when the dog clutch operates.

The present invention has been made in view of the above circumstances, and an object of the present invention is to reduce the size of the forward / backward switching mechanism of a continuously variable transmission and the operating load of a shift sleeve.

In order to achieve the above object, according to the invention of claim 1, the input element connected to the output shaft of the stepless transmission and the input element connected to the differential gear are arranged on the outer periphery of the input element. An annular output element, a fixed element rotatably fitted to the outer periphery of the output shaft, and rotatably supported by the fixed element and arranged between the input element and the output element, the input element and the output. a planetary gear mechanism including a plurality of intermediate elements meshing with the element, and a forward-reverse switching mechanism of a continuously variable transmission provided with a selectively bindable Dogukura' Ji said fixing element to said input element or the transmission case, The dog clutch includes a slider that is axially slidable and non-rotatably fitted to the outer periphery of the fixed element, and a drive ball hole that radially penetrates different positions on the same circumference of the slider in the circumferential direction. A reverse ball hole, a drive ball and a reverse ball held in the drive ball hole and the reverse ball hole, respectively, a shift sleeve for driving the drive ball and the reverse ball in the axial direction, and the like. The fixing element is provided with a drive ball groove and a reverse ball groove formed so as to be axially separated from each other and into which the drive ball and the reverse ball can be fitted, respectively, and the shift sleeve is provided on one side in the axial direction. When driven, the slider moves via the drive ball to be dog-coupled to the dog member integrated with the input element, and the drive ball held in the drive ball hole is placed in the drive ball groove. When the shift sleeve is fitted and the shift sleeve is driven in the other direction in the axial direction, the slider moves via the reverse ball to be dog-coupled to the mission case, and the reverse ball is held in the reverse ball hole. There is proposed a forward / backward switching mechanism of a stepless transmission, which is characterized in that the wheel is fitted in the reverse ball groove.

According to the second aspect of the present invention, in addition to the configuration of the first aspect, the shift sleeve includes a drive pressing protrusion for pressing the drive ball in one axial direction on the other end side in the axial direction. At the same time, a reverse pressing protrusion for pressing the reverse ball to the other in the axial direction is provided on one end side in the axial direction, and the drive pressing protrusion and the reverse pressing protrusion are arranged at different positions in the circumferential direction of the shift sleeve. A forward / backward switching mechanism for a continuously variable transmission is proposed.

Further, according to the invention described in claim 3, in addition to the configuration of claim 2, the drive pressing protrusion and the ball pressing surface of the reverse pressing protrusion have the diameter of the drive ball and the reverse ball. A forward / backward switching mechanism for a continuously variable transmission, which is characterized by inclining in a direction urging inward, is proposed.

Further, according to the invention described in claim 4, in addition to the configuration of any one of claims 1 to 3, the outer peripheral surface of the fixing element is said to be via a plurality of splines separated in the circumferential direction. A forward / backward switching mechanism for a continuously variable transmission has been proposed, which is fitted to the inner peripheral surface of a slider, and the drive ball groove and the reverse ball groove are arranged between two adjacent splines. To.

The sun gear 52 of the embodiment corresponds to the input element of the present invention, the ring gear 54 of the embodiment corresponds to the output element of the present invention, and the carrier 53 of the embodiment and the carrier shaft 67 integrated with the carrier 53. Corresponds to the fixed element of the present invention, and the pinion 55 of the embodiment corresponds to the intermediate element of the present invention.

According to the configuration of claim 1, the dog clutch capable of selectively coupling the fixing element of the planetary gear mechanism to the dog member integrated with the input element or the transmission case is slidable in the axial direction and cannot rotate relative to the outer circumference of the fixing element. It is held by a slider that fits in, a drive ball hole and a reverse ball hole that radially penetrate different positions on the same circumference of the slider in the circumferential direction, and a drive ball hole and a reverse ball hole, respectively. The drive ball and the reverse ball, the shift sleeve that drives the drive ball and the reverse ball in the axial direction, and the drive ball and the reverse ball that are formed so as to be axially separated from each other on the fixing element are fitted to each other. Since it is provided with a possible drive ball groove and a reverse ball groove, when the shift sleeve is driven in one axial direction, the slider moves via the drive ball to be dog-coupled to the fixed element and into the drive ball hole. The held drive ball can be fitted into the drive ball groove to establish a drive range, and when the shift sleeve is driven axially to the other, the slider moves through the reverse ball to the mission case. Along with the dog coupling, the reverse ball held in the reverse ball hole can be fitted into the reverse ball groove to establish the reverse range.
Further, since the drive ball and the reverse ball are arranged on the same circumference of the slider and are driven by a single shift sleeve, the axial dimension of the forward / backward switching mechanism can be miniaturized, and the shift sleeve can be reduced. Drives the slider via the drive ball and the reverse ball, so that the operation load of the shift sleeve can be reduced.

Further, since the drive ball and the reverse ball are arranged on the same circumference of the slider and are driven by a single shift sleeve, the axial dimension of the forward / backward switching mechanism can be miniaturized, and the shift sleeve can be reduced. Drives the slider via the drive ball and the reverse ball, so that the operation load of the shift sleeve can be reduced.

Further, according to the configuration of claim 2, the shift sleeve is provided with a drive pressing protrusion for pressing the drive ball in one axial direction on the other end side in the axial direction, and the reverse ball is axially located on the other end side in the axial direction. The drive pressing protrusion and the reverse pressing protrusion are arranged at different positions in the circumferential direction of the shift sleeve, so that even if the axial dimension of the shift sleeve is reduced, the shift in the drive range is provided. It is possible to prevent the reverse pressing protrusion of the sleeve from interfering with the reverse ball and the drive pressing protrusion 5 from interfering with the drive ball in the reverse range, and the shift sleeve can be miniaturized.

Further, according to the configuration of claim 3, the ball pressing surfaces of the drive pressing protrusion and the reverse pressing protrusion are inclined in the direction of urging the drive ball and the reverse ball inward in the radial direction, so that the drive range and the reverse The drive ball and the reverse ball can be securely fitted into the drive ball groove and the reverse ball groove, respectively, in the range.

Further, according to the configuration of claim 4, the outer peripheral surface of the fixing element is fitted to the inner peripheral surface of the slider via a plurality of splines separated in the circumferential direction, and the drive ball groove and the reverse ball groove are adjacent to each other. Since it is placed between the two splines, the drive ball and the reverse ball can be rolled along the outer peripheral surface of the carrier shaft without interfering with the spline at the time of shift change, and smoothly fill the drive ball groove or the reverse ball groove. It can be fitted to enhance the shift feeling.

It is a skeleton diagram of a power transmission device for a vehicle. It is a detailed view of two parts of FIG. FIG. 2 is a sectional view taken along line 3-3 of FIG. It is a single item drawing of an eccentric disc. It is a figure which shows the relationship between the eccentricity amount of an eccentric disc and a gear ratio. It is a detailed view of 6 parts of FIG. 1 (neutral range). It is an operation explanatory view corresponding to FIG. 6 (drive range). It is an operation explanatory view corresponding to FIG. 6 (reverse range). 9A-9A line sectional view of FIG. 7 and 9B-9B line sectional view of FIG.

Hereinafter, embodiments of the present invention will be described with reference to FIGS. 1 to 9.

As shown in FIG. 1, the vehicle power transmission device includes a crank-type continuously variable transmission T that transmits the driving force of the engine E from the input shaft 12 to the output shaft 13 in a stepless manner, and the output shaft 13 and a differential. It is provided with a forward / backward switching mechanism S that is arranged between the gears D and switches the forward / backward movement of the vehicle.

Hereinafter, the structure of the crank-type continuously variable transmission T will be described with reference to FIGS. 2 to 5.

As shown in FIGS. 2 and 3, the input shaft 12 and the output shaft 13 are supported in parallel with each other by the support frame 11 of the continuously variable transmission T, and the rotation of the input shaft 12 connected to the engine E is 8. It is transmitted to the drive wheels W and W via the transmission units 14, the output shaft 13, the forward / reverse switching mechanism S, and the differential gear D.

Since the structures of the eight transmission units 14 ... Are substantially the same, the structure will be described below with one transmission unit 14 as a representative.

A transmission shaft 15 sharing the axis L is arranged inside the hollow input shaft 12, and is divided into nine in the axis L direction via 10 needle bearings 16 ... On the outer circumference of the transmission shaft 15. The eccentric cam 17 ... Is rotatably supported. A total of nine eccentric cams 17 ... Of the eight transmission units 14 ... Are integrally connected by a plurality of bolts (not shown), and the inner peripheral portions of the nine eccentric cams 17 ... are substantially input shafts. 12 is configured.

The pair of adjacent eccentric cams 17 and 17 are inside the pair of circular cam portions 17a and 17a having a center O1 eccentric with respect to the axis L of the input shaft 12 by a distance d and the cam portions 17a and 17a in the radial direction. It is provided with a formed crescent-shaped guide portion 17b. Eight pinions 18 ... Are integrally formed on the outer circumference of the transmission shaft 15 that shares the axis L with the input shaft 12, and each pinion 18 is a notch of a guide portion 17b having a crescent-shaped cross section of the eccentric cams 17 and 17. It is stored in the portion 17c. The phases of the cam portions 17a and 17a of the eccentric cams 17 and 17 of each transmission unit 14 are shifted by 45 ° from each other.

As shown in FIGS. 3 and 4, on the outer peripheral surfaces of the cam portions 17a and 17a of the eccentric cams 17 and 17, a pair of eccentric recesses 19a formed on both end faces of the disk-shaped eccentric disk 19 in the axial direction L direction, The 19a is rotatably supported via a pair of needle bearings 20, 20. The centers O1 of the eccentric recesses 19a and 19a (that is, the centers O1 of the cam portions 17a and 17a of the eccentric cams 17 and 17) are deviated from the center O2 of the eccentric disk 19 by a distance d. That is, the distance d between the axis L of the input shaft 12 and the centers O1 of the cam portions 17a and 17a of the eccentric cams 17 and 17, the center O1 of the cam portions 17a and 17a of the eccentric cams 17 and 17, and the center O2 of the eccentric disc 19. The distance d between them is the same.

The tooth tips of the ring gear 19b formed so as to communicate between the bottoms of the pair of eccentric recesses 19a and 19a of the eccentric disc 19 slidably abut on the outer peripheral surface of the guide portions 17b of the eccentric cams 17 and 17. Then, the pinion 18 of the transmission shaft 15 exposed from the notch portion 12a (see FIG. 3) of the input shaft 12 meshes with the ring gear 19b of the eccentric disc 19. A counterweight 19c protruding in the direction opposite to the eccentric direction is provided on the outer periphery of the eccentric disk 19. A large end 21a of the connecting rod 21 is supported on the outer circumference of the eccentric disc 19 via a ball bearing 22.

As shown in FIGS. 2 and 3, the one-way clutch 23 provided on the outer periphery of the output shaft 13 includes a ring-shaped swing link 25 connected to the small end portion 21b of the connecting rod 21 via a pin 24. A ring-shaped outer member 26 fixed to the inner circumference of the swing link 25, a ring-shaped inner member 27 arranged inside the outer member 26 and fixed to the output shaft 13, and an inner peripheral surface of the outer member 26. A plurality of rollers 29 ... Arranged in a wedge-shaped space formed between the inner member 27 and the outer peripheral surface of the inner member 27 and urged by a plurality of springs 28 ... Are provided.

Then, at the shaft end of the input shaft 12 opposite to the engine E, the speed change shaft 15 is rotated relative to the input shaft 12 to increase or decrease the eccentricity amount ε of the eccentric disc 19 to shift the continuously variable transmission T. A speed change actuator 30 for changing the ratio is provided.

As shown in FIG. 2, the support frame 11 that supports the eight transmission units 14 ... includes a central frame 31 located at the center in the L direction of the axis and a pair of side frames 32 and 33 located on both sides in the L direction of the axis. Four transmission units 14 ... Are arranged between the central frame 31 and one side frame 32 located on the engine E side, and the center frame 31 and the other side frame located on the anti-engine E side. Four transmission units 14 ... Are arranged between them and 33.

The central frame 31 is an iron plate-shaped member, and includes two bearing support holes 31a and 31b formed on the input shaft 12 side and the output shaft 13 side on both sides in the longitudinal direction thereof.

The side frame 32 located on the engine E side is basically a cast member formed of an aluminum alloy in a cage shape, and a bearing holder 38, which is an iron plate-shaped member, is embedded in the central portion by casting. Bearing support holes 38a and 38b are formed on the input shaft 12 side and the output shaft 13 side of the bearing holder 38, respectively.

The side frame 33 located on the anti-engine E side is also a cast member basically formed in a cage shape with an aluminum alloy, and a bearing holder 39, which is an iron plate-like member, is embedded in the center of the cast member by casting. The structures of the side frame 33 and the bearing holder 39 located on the anti-engine E side overlap with each other because they are plane-symmetrical with respect to the side frame 32 side and the bearing holder 38 located on the engine E side described above. The description is omitted.

The eccentric cam 17 fixed to the central portion of the input shaft 12 in the axis L direction is supported by the bearing support hole 31a of the central frame 31 via the central portion support bearing 34, and both ends of the input shaft 12 in the axis L direction are supported. , The pair of side frames 32, 33 are supported by the bearing support holes 38a, 39a of the bearing holders 38, 39 via the shaft end support bearings 36, 36, respectively. Similarly, the central portion of the output shaft 13 in the axis L direction is supported by the bearing support hole 31b of the central frame 31 via the central portion support bearing 35, and both ends of the output shaft 13 in the axis L direction are on a pair of sides. The bearing holders 38 and 39 of the square frames 32 and 33 are supported by the bearing support holes 38b and 39b via the shaft end support bearings 37 and 37, respectively.

Then, the central frame 31 and the pair of side frames 32, 33 are integrally fastened with bolts 40 ... to assemble the subassembly, and this subassembly is fastened to the inside of the mission case 42 with bolts 41 ... Penetrating the central frame 31. Will be done.

Next, the operation of one transmission unit 14 of the continuously variable transmission T will be described.

As is clear from FIGS. 3 and 5 (A) to 5 (D), when the center O2 of the eccentric disc 19 is eccentric with respect to the axis L of the input shaft 12, the engine E rotates the input shaft 12. The large end 21a of the connecting rod 21 rotates eccentrically around the axis L, so that the connecting rod 21 reciprocates.

As a result, when the connecting rod 21 is pulled to the left side in the drawing in the process of reciprocating, the outer member 26 swings counterclockwise in FIG. 3 together with the swing link 25, and the roller 29 urged by the spring 28 ... ... Is engaged in the wedge-shaped space between the outer member 26 and the inner member 27, and the outer member 26 and the inner member 27 are coupled via the rollers 29 ..., so that the one-way clutch 23 is engaged and the connecting rod 21 is engaged. The movement is transmitted to the output shaft 13. On the contrary, when the connecting rod 21 is pushed to the right side in the drawing in the process of reciprocating, the outer member 26 swings clockwise in FIG. 3 together with the swing link 25, and the rollers 29 ... compress the spring 28 ... When the outer member 26 and the inner member 27 are pushed out from the wedge-shaped space between the member 26 and the inner member 27 and the outer member 26 and the inner member 27 slip each other, the one-way clutch 23 is disengaged and the movement of the connecting rod 21 is transmitted to the output shaft 13. Will not be.

In this way, while the input shaft 12 makes one rotation, the rotation of the input shaft 12 is transmitted to the output shaft 13 for a predetermined time. Therefore, when the input shaft 12 continuously rotates, the output shaft 13 rotates intermittently. The eccentricity ε of the eccentric disks 19 ... Of the eight transmission units 14 ... Are all the same, but the phases in the eccentric direction are shifted by 45 ° from each other, so that the eight transmission units 14 ... By alternately transmitting the rotation to the output shaft 13, the output shaft 13 rotates continuously.

At this time, as the eccentricity amount ε of the eccentric disc 19 increases, the reciprocating stroke of the connecting rod 21 increases, the rotation angle of the output shaft 13 increases once, and the gear ratio of the continuously variable transmission T decreases. On the contrary, as the eccentricity amount ε of the eccentric disk 19 becomes smaller, the reciprocating stroke of the connecting rod 21 becomes smaller, the rotation angle of the output shaft 13 at one time decreases, and the gear ratio of the continuously variable transmission T becomes larger. When the eccentricity ε of the eccentric disc 19 becomes zero, the output shaft 13 does not rotate because the connecting rod 21 stops moving even if the input shaft 12 rotates, and the gear ratio of the continuously variable transmission T becomes maximum ( Infinity).

When the transmission shaft 15 does not rotate relative to the input shaft 12, that is, when the input shaft 12 and the transmission shaft 15 rotate at the same speed, the gear ratio of the continuously variable transmission T is maintained constant. When the speed change shaft 15 is rotated relative to the input shaft 12 by the speed change actuator 30, the eccentric recesses 19a and 19a of the eccentric disc 19 in which the ring gear 19b is meshed with the pinion 18 of each transmission unit 14 are integrated with the input shaft 12. The eccentric cams 17 and 17 are guided by the cams 17a and 17a to rotate, and the eccentric amount ε of the center O2 of the eccentric disk 19 with respect to the axis L of the input shaft 12 changes.

FIG. 5A shows a state in which the gear ratio is the minimum (gear ratio: TD). At this time, the eccentric amount ε of the center O2 of the eccentric disk 19 with respect to the axis L of the input shaft 12 is the axis L of the input shaft 12. The maximum value is equal to 2d, which is the sum of the distance d from the center O1 of the eccentric cams 17 and 17 to the center O1 of the eccentric cams 17 and 17 and the distance d from the center O1 of the eccentric cams 17 and 17 to the center O2 of the eccentric disk 19. When the speed change shaft 15 rotates relative to the input shaft 12, the eccentric disc 19 rotates relative to the eccentric cams 17 and 17 integrated with the input shaft 12, so that FIGS. 5 (B) and 5 (C) show. As shown, the eccentric amount ε of the center O2 of the eccentric disc 19 with respect to the axis L of the input shaft 12 gradually decreases from the maximum value of 2d, and the gear ratio increases. When the speed change shaft 15 further rotates relative to the input shaft 12, the eccentric disc 19 further rotates relative to the eccentric cams 17 and 17 integrated with the input shaft 12, as shown in FIG. 5 (D). Finally, the center O2 of the eccentric disk 19 overlaps the axis L of the input shaft 12, the eccentric amount ε becomes zero, the gear ratio becomes maximum (infinity) (gear ratio: UD), and the power with respect to the output shaft 13 is reached. Transmission is cut off.

Next, the schematic structure of the forward / backward switching mechanism S will be described with reference to FIG.

The forward / backward switching mechanism S includes a planetary gear mechanism 51 arranged on the outer periphery of the output shaft 13. The planetary gear mechanism 51 is rotatably supported by the sun gear 52 fixed to the output shaft 13 and the output shaft 13. The carrier 53 is provided with a ring gear 54 rotatably supported on the outer periphery of the carrier 53, and a plurality of pinions 55 rotatably supported by the carrier 53 and meshed with the sun gear 52 and the ring gear 54. A final drive gear 56 is integrally provided on the outer circumference of the ring gear 54, and the final drive gear 56 meshes with the final driven gear 57 provided in the casing of the differential gear D.

Further, the forward / backward switching mechanism S includes a dog clutch 58 that operates in conjunction with the operation of the shift lever by the driver. When the shift sleeve 59 is in the neutral position shown in the dog clutch 58, the output shaft 13 idles and the neutral range is established. When the shift sleeve 59 moves to the right and switches to the drive position, the output shaft 13 and the carrier 53 are coupled, and the planetary gear mechanism 51 is locked and rotates integrally with the output shaft 13, so that the output shaft 13 rotates. It is transmitted from the ring gear 54 to the differential gear D via the final drive gear 56 and the final driven gear 57, and the vehicle travels forward. When the shift sleeve 59 moves to the left and switches to the reverse position, the carrier 53 is restrained by the transmission case 42, so that the rotation of the output shaft 13 is transmitted from the sun gear 52 to the ring gear 54 as a reverse rotation via the carrier 53. Further, the ring gear 54 is transmitted to the differential gear D via the final drive gear 56 and the final driven gear 57, and the vehicle travels backward.

Next, the specific structure and operation of the forward / backward switching mechanism S will be described with reference to FIGS. 6 to 9.

As shown in FIGS. 6 and 7, the right end of the output shaft 13 is supported on the inner wall of the transmission case 42 via a needle bearing 60, and the planetary gear mechanism 51 serves as an input element fixed to the output shaft 13. The sun gear 52, the ring gear 54 as an output element supported by the transmission case 42 via ball bearings 43 and 44, and a plurality of pinions 55 as intermediate elements meshing with the sun gear 52 and the ring gear 54 at the same time, and output. The shaft 13 is provided with a carrier 53 that is supported via a needle bearing 61 and supports a pinion 55. An annular dog member 62 is connected to the right end of the output shaft 13 by a spline 63, and a thrust bearing 64 is arranged between the mission case 42 and the dog member 62. A plurality of drive dogs 62a ... Are formed on the dog member 62. An annular dog member 65 is connected to the inner wall of the mission case 42 by a spline 66, and a plurality of reverse dogs 65a ... Are formed on the dog member 65.

A tubular carrier shaft 67 is fitted on the outer circumference of the output shaft 13, and the left end of the carrier shaft 67 is connected to the right end of the carrier 53 by a spline 68, and between the right end of the carrier shaft 67 and the dog member 62. Needle bearing 69 and thrust bearing 76 are arranged in the. Therefore, the integrally coupled carrier 53 and carrier shaft 67 are rotatable relative to the integrally coupled output shaft 13 and dog member 62. The carrier 53 and the carrier shaft 67 form a fixing element of the planetary gear mechanism 51.

A tubular slider 70 is coupled to the outer periphery of the carrier shaft 67 by a spline 71 so as to be slidable in the axial direction, and a plurality of drive dogs that can be meshed with the drive dog 62a of the dog member 62 at the right end of the slider 70. 70c ... Is formed, and a plurality of reverse dogs 72a ... That can be meshed with the reverse dogs 65a ... Of the dog member 65 of the mission case 42 are formed on the dog member 72 fixed to the left end of the slider 70. ..

Three drive balls 74 ... And three reverse balls 75 ... Are slidably fitted to the outer circumference of the slider 70 and driven axially by the shift fork 73 on the inner peripheral surface of the shift sleeve 59. It is held alternately at intervals of 60 ° in the circumferential direction.

The cross section of the drive system shown in FIG. 6B is a cross section that passes through the axis of the output shaft 13 and the drive balls 74, and the slider 70 is fitted with three drive balls 74 ... The holes 70a ... Are formed, the carrier shaft 67 is formed with three drive ball grooves 67a ... in which the three drive balls 74 ... Can be fitted, and the shift sleeve 59 is formed with the three drive balls 74. Three drive pressing protrusions 59a ... that can press ... from left to right are formed (see FIG. 9A). Each drive pressing projection 59a includes a ball pressing surface a that presses the drive ball 74 to the right in the axial direction, and a ball holding surface b that presses the drive ball 74 inward in the radial direction.

The reverse cross section shown in FIG. 6A is a cross section that passes through the axis of the output shaft 13 and the reverse ball 75, and the slider 70 is fitted with three reverse balls 75 .... The holes 70b ... Are formed, the carrier shaft 67 is formed with three reverse ball grooves 67b ... to which three reverse balls 75 ... Can be fitted, and the shift sleeve 59 is formed with three reverse balls 75. Three reverse pressing protrusions 59b ... that can press ... from right to left are formed (see FIG. 9B). Each of the reverse pressing protrusions 59b includes a ball pressing surface a that presses the reverse ball 75 to the left in the axial direction, and a ball holding surface b that presses the reverse ball 75 inward in the radial direction.

The three drive ball holes 70a ... And the three reverse ball holes 70b ... Of the slider 70 are formed on the same circumference, but the three drive ball grooves 67a ... And three of the carrier shaft 67. The reverse ball groove 67b ... Is formed at a position deviated by a distance A in the axial direction.

According to the forward / backward switching mechanism S having the above configuration, when the shift sleeve 59 is in the neutral position shown in FIG. 6, the drive ball 74 ... Held in the drive ball hole 70a ... Of the slider 70 is the carrier shaft 67. The reverse ball 75 ... held in the reverse ball hole 70b ... of the slider 70 is radially outward from the reverse ball groove 67a ... Of the carrier shaft 67. The drive dog 70c ... on the right side of the slider 70 is separated from the drive dog 62a ... on the output shaft 13 side, and the reverse dog 72a ... on the left side of the slider 70 ... is the reverse dog on the mission case 42 side. Separate from 65a ... As a result, the output shaft 13, the carrier shaft 67, and the transmission case 42 are separated from each other, and the neutral range is established.

When the shift sleeve 59 is moved to the right from the neutral position shown in FIG. (B) toward the drive position, the drive ball 74 ... Pressed against the ball pressing surface a of the drive pressing protrusion 59a ... Of the shift sleeve 59 is the drive ball. By pressing the hole 70a ..., the slider 70 slides to the right with respect to the carrier shaft 67, and the drive dog 70c ... of the slider 70 meshes with the drive dog 62a ... on the output shaft 13 side, and the slider The drive ball 74… that moves to the right together with the 70 is fitted into the drive ball groove 67a… of the carrier shaft 67, and the ball holding surface b of the drive pressing protrusion 59a… of the shift sleeve 59 is on the drive ball 74…. By riding on and holding the drive ball 74 ... In the drive ball hole 70a ... of the slider 70 and the drive ball groove 67a ... of the carrier shaft 67, as shown in the drive system cross section of FIG. 7B, The slider 70 is locked to the carrier shaft 67 in a coupled state.

At this time, as shown in the reverse cross section of FIG. 7A, the reverse ball 75 ... that moves to the right together with the slider 70 only slides to the right on the outer peripheral surface of the carrier shaft 67, and the reverse ball groove 67b ... Does not fit into.

As a result, the carrier shaft 67 is integrated with the output shaft 13 via the slider 70, the planetary gear mechanism 51 is locked, and the drive range is established.

When the shift sleeve 59 is moved to the left from the neutral position shown in FIG. (B) toward the reverse position, the reverse ball 75… pressed against the ball pressing surface a of the reverse pressing protrusion 59b… of the shift sleeve 59 is the reverse ball. By pressing the hole 70b ..., the slider 70 slides to the left with respect to the carrier shaft 67, and the reverse dog 72a ... Of the slider 70 meshes with the reverse dog 65a ... On the transmission case 42 side, and the slider. The reverse ball 75… that moves to the left together with the 70 is fitted into the reverse ball groove 67b… of the carrier shaft 67, and the ball holding surface b of the reverse pressing protrusion 59b… of the shift sleeve 59 is on the reverse ball 75…. By riding up and holding the reverse ball 75 ... In the reverse ball hole 70b ... of the slider 70 and the reverse ball groove 67b ... of the carrier shaft 67, as shown in the reverse system cross section of FIG. 8 (A), The slider 70 is locked to the mission case 42 in the coupled state.

At this time, as shown in the cross section of the drive system of FIG. 8B, the drive ball 74 ... That moves to the left together with the slider 70 only slides to the left on the outer peripheral surface of the carrier shaft 67, and the drive ball groove 67a ... Does not fit into.

As a result, the carrier shaft 67 is integrated with the mission case 42 via the slider 70, and the carrier 53 of the planetary gear mechanism 51 is restrained by the mission case 42 to establish a reverse range.

As described above, according to the present embodiment, since the drive balls 74 ... Driven by the single shift sleeve 59 and the reverse balls 75 are arranged on the same circumference of the slider 70, they are arranged on the same circumference of the slider 70. The axial dimension of the forward / backward switching mechanism S can be reduced as compared with the case where the forward / backward switching mechanism S is arranged at a position separated in the axial direction, and the shift sleeve 59 is provided via the drive ball 74 ... And the reverse ball 75 ... Since the slider 70 is driven, the operating load of the shift sleeve 59 can be reduced by reducing the frictional force.

In particular, the shift sleeve 59 is provided with a drive pressing protrusion 59a ... That presses the drive ball 74 ... In one axial direction (right side) on the other end side (left end side) in the axial direction, and one end side (right end side) in the axial direction. ) Is provided with a reverse pressing projection 59b ... for pressing the reverse ball in the other axial direction (left), and the drive pressing projection 59a ... and the reverse pressing projection 59b ... are arranged at different positions in the circumferential direction with their phases shifted. Therefore, even if the axial dimension of the shift sleeve 59 is reduced, the reverse pressing protrusion 59b ... Of the shift sleeve 59 does not interfere with the reverse ball 75 ... In the drive range (see FIG. 7A). In addition, the drive pressing protrusion 59a ... Of the shift sleeve 59 does not interfere with the drive ball 74 ... In the reverse range (see FIG. 8B), whereby the axial dimension of the shift sleeve 59 is further reduced. Is achieved.

Further, since the ball pressing surface a of the drive pressing protrusion 59a and the reverse pressing protrusion 59b is inclined in the direction of urging the drive ball 74 and the reverse ball 75 inward in the radial direction, the drive range and the reverse range are used for driving. The ball 74 and the reverse ball 75 can be securely fitted into the drive ball groove 67a and the reverse ball groove 67b, respectively.

Moreover, in the drive range, the ball holding surface b of the drive pressing protrusion 59a of the shift sleeve 59 rides on the drive ball 74 fitted in the drive ball groove 67a of the carrier shaft 67 (see FIG. 7B). , The slider 70 can be reliably held in the drive position, and in the reverse range, the ball of the reverse pressing protrusion 59b of the shift sleeve 59 is placed on the reverse ball 75 fitted in the reverse ball groove 67b of the carrier shaft 67. Since the holding surface b rides on (see FIG. 8A), the slider 70 can be reliably held in the reverse position.

Further, the outer peripheral surface of the carrier shaft 67 is fitted to the inner peripheral surface of the slider 70 via six rows of splines 71 ... Separated at intervals of 60 ° in the circumferential direction (FIGS. 9A and 9B). (See), the three drive ball grooves 67a of the carrier shaft 67 and the three reverse ball grooves 67b ... Are arranged between two adjacent splines 71 and 71, so that the drive balls 74 ... And the reverse ball 75 ... is rolled along the outer peripheral surface of the carrier shaft 67 without interfering with the spline 71 ..., and is smoothly fitted into the drive ball groove 67a ... or the reverse ball groove 67b ... to shift fee. The ring can be raised.

Although the embodiments of the present invention have been described above, the present invention can make various design changes without departing from the gist thereof.

For example, the forward / backward switching mechanism of the present invention is not limited to the crank type continuously variable transmission T of the embodiment, and any other type such as a belt type continuously variable transmission and a toroidal type continuously variable transmission. It can be applied to continuously variable transmissions.

13 Output shaft 42 Mission case 51 Planetary gear mechanism 52 Sun gear (input element)
53 carriers (fixed elements)
54 Ring gear (output element)
55 pinions (intermediate element)
58 Dog Clutch 59 Shift Sleeve 59a Drive Pressing Projection 59b Reverse Pressing Projection
65 Dog member 67 Carrier shaft (fixing element)
67a Drive ball groove 67b Reverse ball groove 70 Slider 70a Drive ball hole 70b Reverse ball hole 71 Spline 74 Drive ball 75 Reverse ball D Differential gear T Continuously variable transmission a Ball pressing surface

Claims (4)

An input element (52) connected to the output shaft (13) of the continuously variable transmission (T) and an annular output element ( 52) connected to the differential gear (D) and arranged on the outer periphery of the input element (52). 54), a fixed element (53, 67) rotatably fitted to the outer periphery of the output shaft (13), and an input element (52) rotatably supported by the fixed element (53, 67). and disposed between said output element (54), a planetary gear mechanism including a plurality of intermediate elements which mesh with those input element (52) and output element (54) (55) (51), and said fixed element (53 , 67) is a forward / backward switching mechanism of a continuously variable transmission provided with a dog clutch (58) capable of selectively coupling the input element (52) or the transmission case (42).
The dog clutch (58) has a slider (70) that fits on the outer periphery of the fixing element (53, 67) so as to be slidable in the axial direction and non-rotatably relative to the slider (70), and the slider (70) in the circumferential direction on the same circumference. A drive ball hole (70a) and a reverse ball hole (70b) that penetrate different positions in the radial direction, and a drive ball hole (70a) and a reverse ball hole (70b) that are held in the drive ball hole (70a) and the reverse ball hole (70b), respectively. On the ball (74) and the reverse ball (75), the shift sleeve (59) that drives the drive ball (74) and the reverse ball (75) in the axial direction, and the fixing element ( 53, 67). The drive ball groove (67a) and the reverse ball groove (67b), which are formed so as to be separated in the axial direction and into which the drive ball (74) and the reverse ball (75) can be fitted, are provided.
When the shift sleeve (59) is driven in one axial direction, the slider (70) moves via the drive ball (74) and is dog-coupled to the dog member (62) integrated with the input element (52). When the drive ball (74) held in the drive ball hole (70a) is fitted into the drive ball groove (67a) and the shift sleeve (59) is driven in the other direction in the axial direction. The reverse ball (75) is moved via the reverse ball (75) to be dog-coupled to the mission case (42) and is held in the reverse ball hole (70b). Is a forward / backward switching mechanism of a continuously variable transmission, characterized in that the ball is fitted in the reverse ball groove (67b). The shift sleeve (59) is provided with a drive pressing protrusion (59a) that presses the drive ball (74) in one axial direction on the other end side in the axial direction, and the reverse ball (75) is provided on one end side in the axial direction. ) Is provided with a reverse pressing protrusion (59b) that presses the other in the axial direction, and the drive pressing protrusion (59a) and the reverse pressing protrusion (59b) are arranged at different positions in the circumferential direction of the shift sleeve (59). The forward / backward switching mechanism of the continuously variable transmission according to claim 1, wherein the stepless transmission is characterized. The ball pressing surface (a) of the drive pressing protrusion (59a) and the reverse pressing protrusion (59b) is in a direction in which the drive ball (74) and the reverse ball (75) are urged inward in the radial direction. The forward / backward switching mechanism of the continuously variable transmission according to claim 2, wherein the stepless transmission is inclined to. The outer peripheral surfaces of the fixing elements ( 53, 67) are fitted to the inner peripheral surfaces of the slider (70) via a plurality of splines (71) separated in the circumferential direction, and the drive ball groove (67a) and the drive ball groove (67a) and the said. The forward / backward advancement of the continuously variable transmission according to any one of claims 1 to 3, wherein the reverse ball groove (67b) is arranged between two adjacent splines (71). Switching mechanism.

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