JP6399900B2 - Continuously variable transmission - Google Patents

Description

  The present invention relates to a continuously variable transmission (CVT) that transmits a rotational driving force of one pulley to another pulley by a chain-type V belt wound between two pulleys.

  For example, in a CVT for a vehicle, a V belt is wound between a primary pulley and a secondary pulley that each form a V groove, and a rotational driving force is transmitted by a frictional force between each pulley and the V belt, and a groove width of each V groove. The gear ratio is changed steplessly by changing. At this time, the frictional force may be insufficient at the end of the speed change region where the contact radius with the V-belt is greatly different between the two pulleys, and a significant slip may occur.

  As a countermeasure, Japanese Patent Application Laid-Open No. 2010-14269 discloses that a CVT using a chain as a V-belt is provided with movable teeth that are movable back and forth in the radial direction at the pulley shaft, and a recess is formed in the chain to form the movable teeth. Techniques for engaging teeth have been proposed. By applying this technology to the secondary pulley, when the pulley groove width is maximized and the contact radius with the chain becomes small, the movable teeth and the chain teeth mesh, and slippage between the secondary pulley and the chain other than friction force In particular, an improvement in performance at the highest Hi (high speed) in the speed change region such as OD (overdrive) is expected.

JP 2010-14269 A

  However, although the above-mentioned maximum groove width meshing structure prevents slipping on the secondary pulley side at the time of maximum Hi in the speed change region, on the primary pulley side, the groove width of the V groove is minimized and the chain contact position is reduced. Because it is farthest from the shaft of the primary pulley, even if it has movable teeth on the shaft, it cannot mesh with the teeth of the chain, and the drive force can still be transmitted only by friction on the primary pulley side. The possibility of slipping remains.

  Therefore, in view of the above-described conventional problems, the present invention is a continuously variable transmission in which the chain and the pulley rotate in a fixed state to prevent mutual slip when the groove width of the V groove in the pulley is minimum. An object is to provide an apparatus.

For this reason, the present invention transmits a rotation by winding a chain between a first pulley and a second pulley that form a V groove with a fixed pulley and a movable pulley, respectively, and the first pulley and the second pulley. In the continuously variable transmission that changes the gear ratio by changing the groove width of each V groove, at least one of the fixed pulley and the movable pulley in at least one of the first pulley and the second pulley is and the movable sheave of the retractable into V groove the selected pulley forms, and a actuating means for advancing and retracting the movable sheave, and a meshing portion that meshes with the chain when the movable sheave is advanced into the V groove It was supposed to be.

  According to the present invention, when the groove width of the V-groove of the first or second pulley having the selected pulley is minimum, the fixed state of the first or second pulley and the chain other than the frictional force can be realized. Slipping is prevented.

It is a figure which shows CVT concerning embodiment. It is an enlarged view which shows the longitudinal cross-section of the primary pulley concerning a 1st Example. It is a figure which shows a movable sheave. It is a figure which shows the holding groove and movable tooth of a movable sheave. It is a figure which shows the state which the movable sheave advanced to the V groove. FIG. 6 is a sectional view taken along the line BB in FIG. 5. It is an enlarged view which shows the longitudinal cross-section of the primary pulley concerning a 2nd Example. It is a figure which shows the state which the movable sheave advanced to the V groove.

Embodiments of the present invention will be described below.
FIG. 1A is a basic configuration diagram of a CVT as a continuously variable transmission according to an embodiment, and FIG. 1B is an enlarged view around a shaft portion of a secondary pulley 3.
The CVT 1 transmits a rotation by winding a V-belt (hereinafter simply referred to as a chain) comprising a chain 15 between the primary pulley 2 and the secondary pulley 3.
The primary pulley 2 is composed of a fixed pulley 20 and a movable pulley 30 as shown in FIG. 2 and later, and receives a primary pressure from a hydraulic pressure control circuit 60 to a primary pressure chamber 38 attached to the movable pulley 30 and receives a V groove. The groove width Wp is changed. This basic configuration is the same as the conventional one.
Although not particularly illustrated, the secondary pulley 3 is similarly composed of a fixed pulley and a movable pulley, and receives a secondary pressure from the hydraulic pressure control circuit 60 in a secondary pressure chamber attached to the movable pulley to change the groove width of the V groove.
The hydraulic control circuit 60 supplies a primary pressure and a secondary pressure that are controlled based on a predetermined shift pattern set in advance according to a traveling state such as an engine output and a traveling speed.

As shown in FIG. 1B, the peripheral surface of the shaft portion 4 of the secondary pulley 3 is provided with a groove width maximum engagement structure having the same basic configuration as that of JP 2010-14269 A.
That is, the movable tooth 10 is held by the holder 6 provided on the peripheral surface of the shaft portion 4, and the tooth 17 corresponding to the movable tooth 10 is formed on the chain link 16 of the chain 15. The holder 6 has a holding groove 7 composed of a narrow groove 8 opened on the outer peripheral surface and a wide groove 9 continuing on the inside.
The movable tooth 10 includes a tooth portion 11 that can advance and retreat in the radial direction along the narrow groove 8 of the holder 6 and a base portion 12 that fits in the wide groove 9. The tooth portion 11 is advanced from the narrow groove 8 by being urged outward in the radial direction by the compression spring 13 disposed in the position.

In the secondary pulley 3, the tooth portion 11 that has advanced from the narrow groove 8 meshes with the tooth 17 of the chain 15 at the highest Hi in the speed change region where the groove width is maximum. Then, on the side where the chain 15 is not wound in the circumferential direction of the shaft portion 4, the base portion 12 is locked to the step between the narrow groove 8 and the wide groove 9 to prevent the holding groove 7 from falling off.
In JP 2010-14269 A, the top of the movable teeth has a flat head, and the teeth of the chain have a large pitch with a recess formed in each chain link corresponding to the flat head. On the other hand, in the present embodiment, each chain link 16 has a plurality of teeth 17 having a small peak and valley and a small pitch, and the top of the tooth part 11 is also correspondingly corresponding to the movable tooth 10. The specific shape is different.

In the present embodiment, the primary pulley 2 has a minimum groove width meshing structure in which the chain and the pulley are fixed when the groove width is minimum.
Hereinafter, the primary pulley 2 will be described in detail with reference to examples.

FIG. 2 is an enlarged view showing a longitudinal section of the primary pulley 2 according to the first embodiment.
The fixed pulley 20 of the primary pulley 2 has a chain support portion 22 integrally with the shaft portion 21, and the shaft portion 21 is rotatably supported on the fixed side of a transmission case or the like at both axial ends via bearings 28 and 29. Has been.
Between the bearings 28 and 29, the movable pulley 30 is supported by the shaft portion 21 through the support hole 31 and faces the chain support portion 22. The movable pulley 30 is integral with the shaft portion 21 in the rotational direction and is slidable in the axial direction by a spline formed between the support hole 31 and the shaft portion 21. The opposed surfaces (sheave surfaces 23 and 33) of the fixed pulley 20 (chain support portion 22) and the movable pulley 30 cooperate to form a V-groove that supports the chain 15.

A drum-like cylinder 35 extends from the movable pulley 30 in a direction opposite to the V-groove forming side, and a disk-like piston 36 fixed to the shaft portion 21 is disposed in the cylinder 35. It can slide relative to the inner wall of the cylinder 35 in the axial direction. A seal ring 37 is held on the outer peripheral edge of the piston 36, whereby an oil-tight primary pressure chamber 38 is formed between the movable pulley 30 (cylinder 35) and the piston 36. The primary pressure chamber 38 is supplied with primary pressure from the hydraulic control circuit 60 through oil passages 24a and 24b formed in the shaft portion 21, and the movable pulley 30 is moved by the control of the primary pressure, so that the sheave surface 23 of the V-groove. , 33 changes the groove width Wp represented by the distance between the outer diameter ends.
An input gear 27 is attached to one end of the shaft portion 21 passing through the bearing 28, and a rotational driving force from the engine side is input.
The oil passage 24a for supplying primary pressure opens at the end of the shaft portion 21 on the input gear 27 side, and is connected to a hydraulic control circuit 60 including an oil pump (not shown).
The above configuration of the primary pulley 2 is the same as that of a known conventional structure.

In this embodiment, the fixed pulley 20 and the movable pulley 30 are formed with ring-shaped accommodation chambers 40 (40 a, 40 b) that open on the sheave surfaces 23 and 33, respectively, and the movable sheave 42 is provided in these accommodation chambers 40. (42a, 42b) are held so as to be movable back and forth in the axial direction.
In the following description, subscripts are omitted when describing common items for a plurality of parts identified by adding subscripts such as a and b to the reference numbers.
Between the movable sheave 42 and the bottom wall in the axial direction of the storage chamber 40, there is provided a return spring 57 of a tension spring type in which both ends are locked by appropriate means to urge the movable sheave 42 in the retracting direction. Yes.

  The leading end of the movable sheave 42a held in the accommodation chamber 40a of the fixed pulley 20 forms a conical surface 43a that is flush with the sheave surface 23 of the chain support portion 22 in the retracted position. The tip of the held movable sheave 42b also forms a conical surface 43b set so as to be flush with the sheave surface 33 of the movable pulley 30 at the retracted position. Each conical surface 43 (43a, 43b) normally functions as a part of each sheave surface 23, 33 except at the time of the highest Hi described later, and constitutes a part of the V groove.

FIG. 2 shows a state where the movable sheave 42 is in the retracted position when the shift region is Lo. Each movable sheave 42 has a recessed portion opened at the rear end of the retracting side to form a spring chamber 44 that accommodates the return spring 57, and the retracted position is defined by the rear end bottoming down on the axial bottom wall of the accommodating chamber 40. Is done.
The movable sheave 42a and the fixed pulley 20 are integrally rotated by a spline or a keyway structure (not shown), and the movable sheave 42b and the movable pulley 30 are also integrally rotated.
The outer diameter of the opening of each storage chamber 40 in the sheave surfaces 23 and 33 is set to be slightly smaller than the inner diameter of the chain 15 at the time of maximum Hi (that is, the minimum groove width Wp of the V-groove). Can advance inside the chain 15 in the V-groove.

FIG. 3 is an enlarged perspective view of the movable sheave 42 as viewed from the rear (retreat side).
A spline and the like for rotating integrally with the fixed pulley 20 and the movable pulley 30 are not shown.
On the outer peripheral surface of the ring-shaped movable sheave 42, holding grooves 45 extending in the axial direction and closed at the front end on the advancing side are provided at equal intervals in the circumferential direction corresponding to the teeth 17 of the chain 15. The teeth 50 are housed and held. The movable teeth 50 may be set at equal intervals according to the predetermined plurality of teeth among the teeth 17 of the chain 15 according to the holding grooves 45. The holding groove 45 opens at the rear end of the movable sheave 42 on the retracting side.
The aforementioned spring chamber 44 is set at a position that does not overlap the holding groove 45 in the circumferential direction of the movable sheave 42. In FIG. 2, the holding groove 45 (and the movable teeth 50) are provided on the movable sheave 42b on the movable pulley 30 side. The spring chamber 44 (and the return spring 57) is drawn on the movable sheave 42a on the fixed pulley 20 side.
4 shows the holding groove 45 and the movable tooth 50, (a) is an enlarged sectional view of the holding groove 45 corresponding to the AA portion in FIG. 2, (b) is an axial rear view of the movable tooth 50, and (c). FIG. 3 is a side view of the movable tooth 50.
As shown in FIG. 4A, the holding groove 45 is composed of a narrow groove 46 opened on the outer peripheral surface of the movable sheave 42 and a wide groove 47 connected to the inner diameter side, and a step is formed therebetween.

As shown in FIGS. 4B and 4C, the movable tooth 50 includes a tooth portion 51 and a base portion 52. The base portion 52 is accommodated in the wide groove 47 and can be locked at the step between the narrow groove 46 and the wide groove 47. The movable tooth 50 has an inclined surface 54 at the outer diameter end at the rear end.
As shown in FIG. 3, the movable tooth 50 is inserted into the holding groove 45 from the rear end opening, and the snap ring 49 is fitted into the ring groove 48 formed from the outer peripheral surface side on the rear end side of the movable sheave 42 to prevent the movable tooth 50 from coming off. Is done.
FIG. 3 shows a state in which only a part of the plurality of movable teeth 50 is held in the holding groove 45, and the snap ring 49 is shown outside the ring groove before fitting.

The movable teeth 50 are accommodated in the accommodation chamber 40 together with the movable sheave 42 at the retracted position. However, when the movable sheave 42 has advanced from the storage chamber 40, the movable teeth 50 can advance radially outward.
The ring groove 48 is set at a position and depth where the snap ring 49 faces the rear end surface of the movable tooth 50, and the snap ring 49 rides on the inclined surface 54 and obstructs the advancement of the movable tooth 50 radially outward. (See FIG. 2). Although not specifically shown, in order to remove the snap ring 49, a small hole is provided in the radial direction from the inner peripheral surface of the movable sheave 42 to the ring groove 48, and the snap ring 49 is formed by a pin passing through the small hole. Extrude it.

Returning to FIG. 2, the bottom wall side of the storage chamber 40 communicates with oil passages 25 a and 25 b formed in the shaft portion 21. The oil passage 25a opens at the end on the bearing 29 side, and is connected to the hydraulic control circuit 60 separately from the oil passage supplying the primary pressure, and receives the sheave control pressure.
When the sheave control pressure is received, the movable sheave 42 slides in the axial direction against the return spring 57 and advances into the V groove.

In the CVT 1 configured as described above, the hydraulic pressure control circuit 60 controls the primary pressure and the secondary pressure, thereby changing the groove width Wp of the primary pulley 2 and the groove width Ws (not shown) of the secondary pulley 3 to perform a shift. Here, the hydraulic pressure control circuit 60 does not supply the sheave control pressure during the shift from the lowest Lo to the lowest Hi in the shift range.
As a result, in the primary pulley 2, the movable sheave 42 of the fixed pulley 20 and the movable pulley 30 is pulled by the return spring 57 and is in the retracted position, as shown in FIG.
Since the movable sheave 42 (conical surface 43) thereof is flush with the sheave surfaces 23 and 33 at the retracted position, the chain 15 smoothly moves onto the movable sheave 42 according to the change in the groove width Wp, and the primary pulley. 2 and can pass through.

Next, when the OD is set to the highest level according to the shift pattern based on the running state, the hydraulic pressure control circuit 60 reduces the secondary pressure and increases the primary pressure so as to minimize the groove width Wp of the primary pulley 2. Thereby, in the primary pulley 2, the chain 15 passes through the opening of the accommodation chamber 40 in the V groove and moves radially outward. The hydraulic control circuit 60 supplies the sheave control pressure to the storage chamber 40 in conjunction with the timing when the groove width Wp reaches the minimum. For example, a groove width detection sensor (not shown) attached to the primary pulley 2 can be used to determine this timing.
Since the chain 15 has already passed through the opening of the storage chamber 40, the movable sheave 42 advances into the V-groove from the opening of the storage chamber 40 without any trouble when receiving the sheave control pressure.
FIG. 5 is a cross-sectional view showing a state where the movable sheave 42 has advanced, and FIG. 6 is a cross-sectional view taken along the line BB in FIG.

When the movable sheave 42 (42a, 42b) advances into the V-groove, the movable tooth 50 accommodated in the holding groove 45 escapes from the restriction by the wall surface on the outer diameter side of the accommodation chamber 40 and is radially outward by centrifugal force. The tooth portion 51 advances from the outer peripheral surface of the movable sheave 42. The advanced tooth portion 51 meshes with the teeth 17 of the chain 15 to form a meshing structure when the groove width is minimum. As a result, the chain 15 and the movable sheave 42, and hence the primary pulley 2, rotate together in a fixed state.
On the side where the movable teeth 50 are not meshed with the chain 15 in the circumferential direction of the movable sheave 42, the base 52 is locked to the step between the narrow groove 46 and the wide groove 47, and is prevented from dropping from the holding groove 45.

  At the highest time, the secondary pressure is reduced in the secondary pulley 3 so that the groove width between the fixed pulley and the movable pulley is maximized, and as shown in FIG. The movable teeth 10 urged radially outward in the structure mesh with the teeth 17 of the chain 15. As a result, the chain 15 and the secondary pulley 3 rotate together in a fixed state.

  Thus, both the primary pulley 2 and the secondary pulley 3 are prevented from slipping with the chain 15 other than the friction force at the time of the highest Hi, so that a hydraulic pressure for obtaining a large friction force is not required. Therefore, the hydraulic control circuit 60 can reduce the primary pressure and the secondary pressure supplied to the primary pressure chamber and the secondary pressure chamber within a range in which the groove width Wp of the V groove is kept to the minimum at the highest Hi.

Next, when the shift state is to be escaped from the highest level, the hydraulic control circuit 60 releases the sheave control pressure. As a result, the movable sheave 42 is moved toward the retracted position by the return spring 57. At this time, the movable teeth 50 protruding from the holding groove 45 of the movable sheave 42 are pushed back into the holding groove 45 by cam action, with the inclined surface 54 pushed against the opening edge on the outer diameter side of the storage chamber 40.
If the primary pressure is further reduced from the minimum groove width maintaining state with a predetermined delay after the sheave control pressure is released so that the movable sheave 42 reaches the retracted position, the groove width Wp increases and interference with the movable sheave 42 occurs. Without change, the chain 15 changes the contact position with the primary pulley 2.

In this embodiment, the primary pulley 2 corresponds to the first pulley in the invention, and the secondary pulley 3 corresponds to the second pulley. The fixed pulley 20 and the movable pulley 30 correspond to the selected pulley, the movable sheave 42 corresponds to the movable portion, the holding groove 45 corresponds to the holding portion, and the movable tooth 50 corresponds to the meshing portion.
Further, the structure in which the movable sheave 42 is advanced from the accommodating chamber 40 by supplying the sheave control pressure from the hydraulic control circuit 60 to the accommodating chambers 40 of the fixed pulley 20 and the movable pulley 30 constitutes the operating means in the present invention. .
The primary pressure chamber 38 corresponds to the pressure chamber attached to the movable pulley of the first pulley, and the secondary pressure chamber (not shown) corresponds to the pressure chamber attached to the movable pulley of the second pulley.

  The first embodiment is configured as described above. In the CVT 1 in which the chain 15 is wound between the primary pulley 2 and the secondary pulley 3 to transmit the rotation, both the fixed pulley 20 and the movable pulley 30 of the primary pulley 2 are respectively connected. The movable sheave 42 that can move back and forth into the V-groove formed by and holds the movable tooth 50 is provided, and the movable tooth 50 can be engaged with the chain 15 by advancing the movable sheave 42 into the V-groove. Even when the groove position where the contact position of the primary pulley 2 is greatly separated from the shaft portion 21 of the primary pulley 2 is the minimum, the fixed state of the chain 15 and the primary pulley 2 can be realized by other than the frictional force, and mutual sliding is prevented.

  In particular, the movable sheave 42 has a ring shape, and the fixed pulley 20 and the movable pulley 30 are opened to the inside of the winding inner diameter of the chain 15 when the groove width Wp of the V groove on the respective sheave surfaces 23 and 33 is the smallest. The movable sheave 42 has a holding groove 45 that opens radially outward to receive the movable teeth 50, and supplies the sheave control pressure to the storage chamber 40 to move the movable sheave 42. Is moved forward in the axial direction from the retracted position in the storage chamber 40, the tooth portion 51 of the movable tooth 50 advances from the opening of the holding groove 45 due to centrifugal force and meshes with the teeth 17 formed on the chain 15. The movable tooth 50 and the chain 15 can be automatically engaged with each other only by advancing 42 without requiring any special urging means.

The movable tooth 50 has an inclined surface 54 at the rear end of the tooth portion 51 and is stored in the holding groove 45 by a cam action with the opening edge of the storage chamber 40 when the movable sheave 42 is retracted. The configuration is simple in terms of points.
And since the spring 57 which urges the movable sheave 42 to the retracted position is provided between the movable sheave 42 and the axial bottom wall of the storage chamber 40, when the hydraulic pressure to the storage chamber 40 is eliminated, it is quickly Return to the retracted position and high responsiveness.

  The movable sheave 42 has a conical surface 43 at the tip that is flush with the sheave surfaces 23 and 33 of the fixed pulley 20 and the movable pulley 30 at the retracted position stored in the storage chamber 40. It functions as a part of the sheave surfaces 23 and 33 in the speed change region other than the time when the vehicle is advanced, and a smooth speed change is ensured.

  The hydraulic control circuit 60 reduces the primary pressure and the secondary pressure after the movable sheave 42 advances when the groove width Wp of the primary pulley 2 is minimum and the tooth portion 51 of the movable tooth 50 meshes with the tooth 17 of the chain 15. This reduces the load on the oil pump and improves fuel economy and durability.

In the first embodiment, the movable sheave 42 having the movable teeth 50 is provided on both the fixed pulley 20 and the movable pulley 30 of the primary pulley 2, but when the transmission torque is relatively small, the movable sheave is fixed pulley. It is good also as providing only in either one of a movable pulley.
As an example, FIG. 7 is a longitudinal sectional view showing a second embodiment in which the movable sheave is provided only on the movable pulley in the primary pulley.
In the primary pulley 2X, the ring-shaped accommodation chamber 40X that holds the movable sheave 42X in the movable pulley 30X has an outer diameter slightly smaller than the winding inner diameter of the chain 15 when the groove width Wp of the V-groove is the minimum as in the first embodiment. On the other hand, the inner diameter of the movable pulley 30X extends to the support hole 31 supported by the shaft portion 21 of the fixed pulley 20X. In other words, the storage chamber 40X has the shaft portion 21 as a wall surface on the inner diameter side.

The movable sheave 42X held in the storage chamber 40X is a cone in which the leading end on the advancing side is flush with the sheave surface 33 of the movable pulley 30X at the retracted position with the rear end bottomed on the axial bottom wall of the storage chamber 40X. A surface 43X is formed. FIG. 7 shows the retracted position state.
On the outer peripheral surface of the movable sheave 42X, similarly to the first embodiment, holding grooves 45 extending in the axial direction and closed at the advancing side are provided at predetermined intervals in the circumferential direction corresponding to the teeth 17 of the chain 15, The movable tooth 50 is held in the holding groove 45 and is prevented from coming off by a snap ring 49.

In this embodiment, a push spring type return spring 58 is provided between the fixed pulley 20X and the movable sheave 42X on the inner diameter side of the position of the chain 15 at the time of the minimum Lo shown in FIG. 7, that is, when the groove width Wp of the V groove is maximum. , They are spaced apart so as not to interfere with the chain 15. The return springs 58 are provided at a plurality of locations around the shaft portion 21 at equal intervals.
Recessed spring receiving portions 26 and 56 are formed at the bases of the fixed pulley 20X and the shaft portion 21 side of the movable sheave 42X so as to be opposed to each other in the axial direction. Both ends of the return spring 58 are supported by the spring receiving portions 26 and 56 and can extend and contract in the axial direction along the outer peripheral surface of the shaft portion 21, and urge the movable sheave 42X in the retracting direction.
A sheave control pressure from a hydraulic control circuit 60 (see FIG. 2) is supplied to the storage chamber 40X through oil passages 25a and 25b formed in the shaft portion 21. Other configurations are the same as those of the first embodiment, and the same reference numerals are given to the same portions.

The sheave control pressure is not supplied from the lowest Lo to the lowest Hi in the speed change region, and the movable sheave 42X pushed by the return spring 58 and in the retracted position functions as the sheave surface of the movable pulley 30X. To do.
When the groove width Wp is the minimum Hi, as shown in FIG. 8, the sheave control pressure is supplied, and the movable sheave 42X advances into the V groove against the return spring 58, and is the same as in the first embodiment. Furthermore, the movable tooth 50 moves radially outward by centrifugal force. Thereby, the tooth part 51 of the movable tooth 50 meshes with the tooth 17 of the chain 15, and the chain 15 and the primary pulley 2X rotate integrally in a fixed state.
The operation for escaping from the highest Hi is the same as in the first embodiment.

In this embodiment, the primary pulley 2X corresponds to the first pulley in the invention, and the secondary pulley 3 corresponds to the second pulley. The movable pulley 30X corresponds to the selected pulley, the movable sheave 42X corresponds to the movable portion, the holding groove 45 corresponds to the holding portion, and the movable tooth 50 corresponds to the meshing portion.
Further, the structure in which the movable sheave 42X is advanced from the storage chamber 40X by supplying hydraulic pressure from the hydraulic control circuit 60 to the storage chamber 40X of the movable pulley 30X constitutes the operating means in the present invention.
The primary pressure chamber 38 corresponds to a pressure chamber attached to the movable pulley of the first pulley, and the secondary pressure chamber corresponds to a pressure chamber attached to the movable pulley of the second pulley.

The second embodiment is configured as described above, and has the same effect as the first embodiment.
Further, since the movable sheave 42X is provided only on the movable pulley 30X, the configuration is simplified and the cost is reduced as compared with the first embodiment.
The movable sheave 42X has an inner diameter smaller than the inner diameter of the chain 15 when the groove width Wp of the V-groove is maximum, and the groove width Wp between the movable sheave 42X and the fixed pulley 20X is maximum. Since a push spring type spring 58 is arranged on the inner diameter side of the chain 15 and the movable sheave 42X is biased to the retracted position, no spring locking means is required in the storage chamber 40X, and assembly is easy. .
The return spring 58 may be a single coil spring concentric with the shaft 21 instead of being provided around the shaft 21.

  In the embodiment, the present invention is applied to the primary pulley, and the groove width of the primary pulley is the minimum, that is, the chain and the pulley are fixed at the highest Hi in the speed change region. It may be applied to the secondary pulley, and the chain and the pulley may be fixed when the groove width of the secondary pulley is the minimum, that is, the lowest Lo in the speed change region, and is also applied to both the primary pulley and the secondary pulley. You can also.

1 CVT
2, 2X Primary pulley 3 Secondary pulley 4 Shaft portion 6 Holder 7 Holding groove 8 Narrow groove 9 Wide groove 10 Movable tooth 11 Tooth portion 12 Base portion 13 Compression spring 15 Chain 16 Chain link 17 Tooth 20, 20X Fixed pulley 21 Shaft portion 22 Chain Support portion 23, 33 Sheave surface 24a, 24b Oil passage 25a, 25b Oil passage 26, 56 Spring receiving portion 27 Input gear 28, 29 Bearing 30, 30X Movable pulley 31 Support hole 35 Cylinder 36 Piston 37 Seal ring 38 Primary pressure chamber 40 40a, 40b, 40X Containment chamber 42, 42a, 42b, 42X Movable sheave 43, 43a, 43b, 43X Conical surface 44 Spring chamber 45 Holding groove 46 Narrow groove 47 Wide groove 48 Ring groove 49 Snap ring 50 Movable tooth 51 Tooth part 52 Base 5 4 Inclined surface 57, 58 Return spring 60 Hydraulic control circuit Mp Groove width

Claims (7)

A chain is wound between a first pulley and a second pulley, each of which forms a V-groove with a fixed pulley and a movable pulley, to transmit the rotation, and each V of the first pulley and the second pulley is transmitted. In a continuously variable transmission that changes the gear ratio by changing the groove width of the groove,
A movable sheave capable of advancing and retracting into the V-groove formed by the selected pulley on at least one of the fixed pulley and the movable pulley in at least one of the first pulley and the second pulley; and a actuating means for advancing and retracting the movable sheave,
The continuously variable transmission according to claim 1, wherein the movable sheave has a meshing portion that meshes with the chain when the sheave moves into the V groove. The movable sheave is ring-shaped;
The selected pulley has an accommodation chamber that opens inside the winding inner diameter of the chain and holds the movable sheave when the groove width of the V groove formed by the selected pulley on the sheave surface is the smallest. Prepared,
The movable sheave has a holding portion that opens outward in the radial direction around the rotation axis of the selected pulley and accommodates the meshing portion;
The actuating means advances the movable sheave in the axial direction from the retracted position stored in the storage chamber by supplying hydraulic pressure to the storage chamber from a hydraulic control circuit including an oil pump when the groove width of the V-groove is minimum. Let
The meshing portion includes a tooth portion that is advanced from an opening of the holding portion by a centrifugal force when the movable sheave is advanced into the V-groove and meshes with a tooth formed on the chain. The continuously variable transmission according to Item 1. The actuating means includes a tension spring type spring that urges the movable sheave to the retracted position between the movable sheave and an axial bottom wall of the storage chamber. The continuously variable transmission according to 2. The movable sheave has an inner diameter smaller than the inner diameter of the chain when the groove width of the V-groove is maximum;
It said actuating means, between the pulley facing the movable sheave and the movable sheave, an inner diameter side of the chain when the groove width of the V groove is maximum, urging the movable sheave to the retracted position The continuously variable transmission according to claim 2, further comprising a push spring type spring. The meshing portion has an inclined surface at a rear end of the tooth portion, and is stored in the holding portion by a cam action with an opening edge of the accommodation chamber when the movable sheave is retracted to the accommodation chamber. The continuously variable transmission according to any one of claims 2 to 4. The movable sheave is in the retracted position, the tip of the movable sheave according to any one of claims 2 to 5, characterized in that is set to the sheave surfaces flush of the selected pulley Continuously variable transmission. The first pulley and the second pulley are supplied with hydraulic pressure from the hydraulic control circuit to pressure chambers attached to the movable pulleys to change the groove width of the V groove,
The hydraulic control circuit includes the selected pulley after the groove width of the V groove formed by the selected pulley is minimum, the movable sheave advances and the meshing portion meshes with the chain. The continuously variable transmission according to any one of claims 2 to 6, wherein an oil pressure to the pressure chamber in the first pulley or the second pulley is reduced.

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