JP2018044639A - Sheave drive device for continuously variable transmission - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sheave drive device for a continuously variable transmission that is compact and excellent in mountability to a vehicle.SOLUTION: An electrically-driven type linear motion actuator 4 for moving a movable sheave 3 in an axial direction includes: an electric motor 20 configured into a hollow annular shape so that a pulley shaft 1 is inserted therein; a nut 21 disposed coaxially with the electric motor 20 and being rotatably driven by the electric motor 20; and a hollow screw shaft 22 threadably engaged with the nut 21 and moving in the axial direction integrally with the movable sheave 3 with rotation of the nut 21.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a sheave drive device that moves a movable sheave of a continuously variable transmission in an axial direction.

  2. Description of the Related Art A belt type continuously variable transmission is known as a continuously variable transmission capable of shifting and outputting the rotation of an automobile engine and changing its transmission ratio continuously. The belt-type continuously variable transmission has a driving side V-groove pulley, a driven side V-groove pulley, and a V-belt wound between these pulleys.

  The drive side V-groove pulley is composed of a fixed sheave and a movable sheave facing each other in the axial direction. The fixed sheave is fixed to the outer periphery of the pulley shaft, and the movable sheave is supported on the outer periphery of the pulley shaft so as to be movable in the axial direction. Then, by moving the movable sheave in the axial direction, the distance between the fixed sheave and the movable sheave can be changed, thereby changing the winding radius of the V belt around the driving side V-groove pulley.

  Similarly to the drive side V-groove pulley, the driven side V-groove pulley is also composed of a fixed sheave and a movable sheave. When the movable sheave of the driving side V-groove pulley is moved in the axial direction and the movable sheave of the driven side V-groove pulley is moved in the axial direction, the winding radius of the V belt around the driving side V-groove pulley and the driven side The wrapping radius of the V-belt with respect to the V-groove pulley changes, and thereby the speed ratio of the rotation transmitted from the drive-side V-groove pulley to the driven-side V-groove pulley changes.

  By the way, the applicant of the present application has already proposed a sheave drive device that moves the movable sheave in the axial direction, as in Patent Document 1, using an electric linear actuator. The sheave drive device of Patent Document 1 includes a nut coupled to move in the axial direction integrally with a movable sheave, a screw shaft that is screw-engaged with the nut, an electric motor, and a nut that decelerates the rotation of the electric motor. When the electric motor rotates, the rotation is decelerated by the reducer and transmitted to the nut, and the nut and the movable sheave move together in the axial direction.

JP 2007-263284 A

  In the sheave drive device of Patent Document 1, the electric motor is disposed in parallel with and separated from the pulley shaft provided with the fixed sheave and the movable sheave, and the reduction gear is parallel between the electric motor and the pulley shaft. Has been placed.

  The inventor of the present application has noticed that there is a problem that the installation space of the sheave drive device having the configuration of Patent Document 1 is relatively large and the mountability to a vehicle is poor. Then, he noticed that there was a dead space around the pulley shaft, and realized the possibility that the sheave drive device could be made compact by making effective use of this space.

  The problem to be solved by the present invention is to provide a sheave drive device for a continuously variable transmission that is compact and excellent in mountability to a vehicle.

  In order to solve the above-described problems, the present invention provides a sheave drive device for a continuously variable transmission having the following configuration.

A pulley shaft;
A fixed sheave fixed to the outer periphery of the pulley shaft;
A movable sheave which is arranged on the outer periphery of the pulley shaft so as to face the fixed sheave in the axial direction and is supported so as to be movable in the axial direction with respect to the pulley shaft in a state of being prevented from rotating around the pulley shaft;
In a sheave drive device for a continuously variable transmission having an electric linear motion actuator that moves the movable sheave in an axial direction,
The electric linear actuator is
An electric motor configured in a hollow ring through which the pulley shaft passes;
A nut arranged coaxially with the electric motor on the radially inner side of the hollow annular electric motor and on the radially outer side of the pulley shaft, and rotated by the electric motor;
A hollow screw shaft that is screw-engaged with the nut and moves in the axial direction integrally with the movable sheave by rotation of the nut;
A sheave drive device for a continuously variable transmission.

  In this case, a hollow annular motor is used as the electric motor for rotating the nut, and the pulley shaft is passed through the hollow annular electric motor. Therefore, the dead space around the pulley shaft is small. Further, since the nut is disposed radially inside the hollow annular electric motor and radially outside the pulley shaft, the installation space for the electric motor and the nut is short in the axial direction. Therefore, the sheave drive device is compact and has excellent mountability on a vehicle.

  It is preferable to employ a configuration in which a hollow annular speed reducer through which the pulley shaft passes is further provided, and the speed of the electric motor is reduced by the speed reducer and transmitted to the nut.

  In this case, since the hollow annular gear is used as the speed reducer that decelerates the rotation of the electric motor and transmits it to the nut, the dead space around the pulley shaft can be effectively reduced. Further, since the electric motor rotates the nut via the speed reducer, the size of the electric motor required to move the movable sheave in the axial direction can be made smaller than when the electric motor directly rotates the nut. it can. Therefore, the sheave drive device can be effectively made compact.

  The speed reducer is preferably arranged so as to be adjacent to the electric motor in the axial direction and located on the outer diameter side of the nut.

  In this case, for example, compared with the case where a reduction gear is incorporated between the inner diameter of the electric motor and the outer diameter of the nut, the increase in the diameter of the sheave drive device can be suppressed, and the sheave drive device can be effectively made compact. Can be realized.

The speed reducer is
The rotation of the electric motor is input, and an eccentric shaft portion having a cylindrical outer periphery eccentric from the rotation center;
An external gear rotatably supported on the outer periphery of the eccentric shaft portion;
An internal gear that meshes with the external gear so that the external gear rotates at a speed slower than the rotation of the eccentric shaft when the eccentric shaft rotates.
An output carrier for taking out rotation of the external gear and transmitting it to the nut;
It is preferable to employ one having

  If a reduction gear having this configuration is employed, a large reduction ratio can be obtained in a small space, so that the sheave drive device can be made particularly compact.

The electric motor employs a hollow cylindrical rotor disposed to face the outer periphery of the nut, an annular stator that imparts rotational force to the rotor, and a motor housing that houses the stator. be able to.
In this case, as the internal gear, it is preferable to employ one constituted by a plurality of external pins fixed to the motor housing.

  If it does in this way, since the motor housing of an electric motor serves as the member for fixing the outer pin of a reduction gear, the number of parts of a reduction gear can be suppressed and a reduction gear can be made compact.

  In this case, it is preferable that the outer pin is formed integrally with the motor housing without a joint.

  If it does in this way, since the rigidity of an outer pin can be secured using the rigidity of a motor housing, it becomes possible to make a reduction gear especially compact effectively.

  A spacer facing the movable sheave in the axial direction is fixed to an end portion of the screw shaft close to the movable sheave. Between the spacer and the facing surface of the movable sheave, the screw shaft and the movable sheave. It is preferable to incorporate a thrust bearing that supports the axial load acting in between.

  In this way, the movable sheave can be supported in the axial direction with high rigidity.

  In this case, it is preferable that the thrust bearing is a needle roller with a cage having needle rollers that are in direct contact with the movable sheave.

  In this way, the axial length of the sheave drive device can be reduced particularly effectively.

  The sheave drive device according to the present invention uses a hollow annular electric motor for rotationally driving the nut, and has a configuration in which the pulley shaft is passed through the hollow annular electric motor. Therefore, the dead space around the pulley shaft Is small. Further, since the nut is disposed radially inside the hollow annular electric motor and radially outside the pulley shaft, the installation space for the electric motor and the nut is short in the axial direction. Therefore, the sheave drive device of the present invention is compact and has excellent mountability on a vehicle.

Sectional drawing which shows the sheave drive device of the continuously variable transmission concerning embodiment of this invention Sectional view along the line II-II in FIG.

  FIG. 1 shows a sheave drive device for a continuously variable transmission according to an embodiment of the present invention. The sheave drive device includes a pulley shaft 1, a fixed sheave 2 and a movable sheave 3 that are arranged on the outer periphery of the pulley shaft 1 so as to face each other in the axial direction, and an electric linear actuator that moves the movable sheave 3 in the axial direction. 4.

  The fixed sheave 2 is fixed to the outer periphery of the pulley shaft 1. In the figure, the fixed sheave 2 and the pulley shaft 1 are formed integrally with the pulley shaft 1 so that the fixed sheave 2 is fixed to the pulley shaft 1. However, the fixed sheave 2 and the pulley shaft 1 can be separated. is there.

  The movable sheave 3 is supported so as to be movable in the axial direction with respect to the pulley shaft 1 while being prevented from rotating on the outer periphery of the pulley shaft 1. As such a support structure, for example, an axial groove 5 extending in the axial direction is formed on the inner periphery of the movable sheave 3, and an axial protrusion 6 extending in the axial direction is formed on the outer periphery of the pulley shaft 1. It is possible to employ a configuration in which the shaft 5 and the axial projection 6 are in contact with each other so as to be slidable in the axial direction (for example, spline fitting, key groove fitting, etc.).

  The opposed surface 7 of the fixed sheave 2 to the movable sheave 3 and the opposed surface 8 of the movable sheave 3 facing the fixed sheave 2 are tapered so that the distance between the opposed surfaces 7 and 8 gradually increases toward the outer diameter side. It is made into a shape. A V-belt 9 of the continuously variable transmission is wound between the opposed surfaces 7 and 8 of the fixed sheave 2 and the movable sheave 3, and the winding radius of the V-belt 9 depends on the position of the movable sheave 3 in the axial direction. Change.

  The pulley shaft 1 is rotatably supported by a fixed sheave side bearing 10 and a movable sheave side bearing 11. The fixed sheave bearing 10 is attached to the outer periphery of the pulley shaft 1 between the shaft end of the pulley shaft 1 on the fixed sheave 2 side and the fixed sheave 2. The movable sheave side bearing 11 is attached to the outer periphery of the pulley shaft 1 between the shaft end of the pulley shaft 1 on the movable sheave 3 side and the movable sheave 3. A gear 12 for transmitting the rotation of the automobile engine is fixed to the pulley shaft 1. The gear 12 is fitted and fixed to the outer periphery of the pulley shaft 1 between the movable sheave side bearing 11 and the shaft end of the pulley shaft 1 on the movable sheave 3 side.

  The electric linear actuator 4 includes an electric motor 20, a nut 21, a screw shaft 22 that is screw-engaged with the nut 21, and a speed reducer 23 that decelerates the rotation of the electric motor 20 and transmits it to the nut 21.

  The electric motor 20 is configured as a hollow ring through which the pulley shaft 1 passes. The electric motor 20 includes a hollow cylindrical rotor 24 disposed to face the outer periphery of the nut 21, an annular stator 25 that applies a rotational force to the rotor 24, and a motor housing 26 that houses the stator 25.

  The rotor 24 includes a rotor cylinder 28 rotatably supported by a pair of bearings 27 attached to the motor housing 26, and an annular rotor core 29 fixed to the outer periphery of the rotor cylinder 28. The rotor core 29 is configured by assembling a permanent magnet 30 to a laminate of electromagnetic steel plates. The permanent magnet 30 is assembled so that N poles and S poles appear alternately along the circumferential direction of the outer periphery of the rotor core 29.

  The stator 25 includes an annular stator core 32 having a plurality of teeth 31 arranged at equal intervals in the circumferential direction so as to surround the rotor 24, and an electromagnetic coil 33 wound around each tooth 31 of the stator core 32. The stator core 32 is fixed to the inner periphery of the motor housing 26. When the electromagnetic coil 33 is energized, a rotational force is generated in the rotor core 29 by an electromagnetic force acting between the stator core 32 and the rotor core 29, and the rotor core 29 and the rotor cylinder 28 rotate integrally by the rotational force.

  The motor housing 26 includes a cylindrical wall portion 34 that surrounds the outer periphery of the stator 25, a first annular wall portion 35 that projects radially inward from an axial end portion of the cylindrical wall portion 34 on the side far from the movable sheave 3, And a second annular wall portion 36 projecting radially inward from the axial end portion of the cylindrical wall portion 34 near the movable sheave 3. Of the pair of bearings 27 that support the rotor cylinder 28, one bearing 27 is attached to the inner periphery of the first annular wall portion 35, and the other bearing 27 is attached to the inner periphery of the second annular wall portion 36. ing.

  The nut 21 is disposed coaxially with the rotor cylinder 28 on the radially inner side of the rotor cylinder 28 of the electric motor 20 and on the radially outer side of the pulley shaft 1. That is, the nut 21 is incorporated in an annular space sandwiched between the inner periphery of the hollow cylindrical electric motor 20 and the outer periphery of the pulley shaft 1. The nut 21 is a ball nut that engages with the outer periphery of the screw shaft 22 via a ball 37. Each time the ball 37 makes one round along the inner circumferential thread groove of the nut 21, the nut 37 is placed on the nut 21 so that the ball 37 passes over the outer thread of the threaded shaft 22 and returns to the original thread groove. It has a deflector 38 to guide it. The deflector 38 is inserted into a radial through hole formed in the nut 21 and incorporated from the outer diameter side.

  The nut 21 is supported in the axial direction by the backup plate 40 via the thrust bearing 39, and the axial movement in the direction away from the movable sheave 3 is restricted by this support. The backup plate 40 is supported by the outer ring of the movable sheave side bearing 11. The movable sheave side bearing 11 is a radial bearing (in the figure, a deep groove ball bearing). The backup plate 40 is a stationary member fixed to a case of a continuously variable transmission (not shown) with a bolt. If the thrust bearing 39 is a needle roller bearing, the axial length of the sheave drive device can be effectively reduced in size. In this case, if the thrust bearing 39 is a needle roller with a cage that does not have a bearing disc, the axial length of the sheave drive device can be reduced particularly effectively, which is preferable.

  The screw shaft 22 is formed in a hollow cylindrical shape through which the pulley shaft 1 passes. A key groove 41 (see FIG. 2) extending in the axial direction is formed on the inner periphery of the screw shaft 22. A key member 42 fixed to the backup plate 40 is engaged with the key groove 41 so as to be slidable in the axial direction. By fitting the key groove 41 and the key member 42, the screw shaft 22 is locked to the backup plate 40 (stationary member) while being movable in the axial direction with respect to the pulley shaft 1.

  A spacer 43 facing the movable sheave 3 in the axial direction is fixed to the end of the screw shaft 22 on the side close to the movable sheave 3. A thrust bearing 44 that supports an axial load acting between the screw shaft 22 and the movable sheave 3 is incorporated between the facing surfaces of the spacer 43 and the movable sheave 3. The outer diameter of the spacer 43 is at least larger than the inner diameter of the nut 21. Thereby, the axial load which acts on the screw shaft 22 from the movable sheave 3 can be received in a wide area. When the thrust bearing 44 is a needle roller with a cage having a needle roller that is in direct contact with the movable sheave 3, the axial length of the sheave drive device can be reduced particularly effectively. The movable sheave 3 is pressed in the axial direction through the thrust bearing 44 from the screw shaft 22 driven in the axial direction by the driving force of the electric motor 20, and at the same time, the movable sheave 3 is axially directed away from the fixed sheave 2. The screw shaft 22 is always pressed from the movable sheave 3 in the axial direction via the thrust bearing 44.

  The reduction gear 23 is a hollow ring through which the pulley shaft 1 passes, and is disposed adjacent to the electric motor 20 in the axial direction and on the outer diameter side of the nut 21. The speed reducer 23 includes an eccentric shaft portion 50 fixed to the rotor cylinder 28 of the electric motor 20, an external gear 51 rotatably supported on the outer periphery of the eccentric shaft portion 50, and an internal tooth that meshes with the external gear 51. A gear 52 and an output carrier 53 are included. Here, in the electric motor 20, the end of the rotor cylinder 28 on the side far from the movable sheave 3 protrudes in the axial direction from the first annular wall portion 35 of the motor housing 26. The eccentric shaft part 50 is fixed.

As shown in FIG. 2, the eccentric shaft portion 50 has a cylindrical outer periphery that is eccentric from the rotation center O ₁ of the eccentric shaft portion 50 (that is, the rotation center of the rotor 24 of the electric motor 20). The eccentric shaft portion 50 can be formed integrally with the rotor cylinder 28 without any joints. However, as shown in the figure, the eccentric shaft portion 50 is an annular member separate from the rotor cylinder 28, and it When fixedly attached to the outer periphery of the rotor cylinder 28, it is possible to increase the eccentricity between the center O ₂ of the cylindrical outer circumference of the rotation center O ₁ and the eccentric shaft portion 50 of the eccentric shaft portion 50. The eccentric shaft portion 50 has an annular shape whose radial width changes along the circumferential direction.

  The external gear 51 is rotatably supported on the outer periphery of the eccentric shaft portion 50. In the figure, the configuration in which the cylindrical surface on the outer periphery of the eccentric shaft portion 50 and the cylindrical surface on the inner periphery of the external gear 51 are in contact with each other in a circumferential direction is slidable. A rolling bearing may be incorporated between the cylindrical surfaces on the inner periphery of the external gear 51. A plurality of external teeth 54 are formed on the outer periphery of the external gear 51 at an equal pitch in the circumferential direction. The external tooth 54 has a tooth profile of a trochoidal curve (a locus drawn by a fixed point inside the moving circle when the moving circle rolls around the outer periphery of the fixed circle). The external gear 51 is disposed to face the first annular wall 35 of the motor housing 26 in the axial direction.

The internal gear 52 is composed of a plurality of outer pins 55 arranged at equal pitches in the circumferential direction on the circumference centered on the rotation center O ₁ of the eccentric shaft portion 50. Each outer pin 55 has a cylindrical outer periphery. The number of external pins 55 is one more than the number of external teeth 54 of the external gear 51. It is possible to form the outer pins 55 separately from the motor housing 26 and fix the outer pins 55 to the housing with bolts or the like. Is formed integrally with the first annular wall 35) without a seam.

  As shown in FIG. 1, the output carrier 53 includes a cylindrical portion 56 that fits on the outer periphery of the nut 21, and a flange portion 57 that is formed at one end of the cylindrical portion 56. The cylindrical portion 56 is fitted to the outer periphery of the nut 21 with a tightening margin. When the output carrier 53 rotates, the nut 21 rotates together with the output carrier 53. The inner periphery of the cylindrical portion 56 is in contact with the deflector 38 incorporated in the nut 21 and restricts the movement of the deflector 38 outward in the radial direction. The flange portion 57 is sandwiched between the nut 21 and the thrust bearing 39 in the axial direction, and also functions as a raceway for the thrust bearing 39 (needle roller with cage).

  As shown in FIGS. 1 and 2, a plurality of inner pins 58 are provided on the side surface of the external gear 51 far from the movable sheave 3 at intervals in the circumferential direction. Each inner pin 58 has a cylindrical outer periphery. A pin hole 59 having a cylindrical inner periphery that contacts the outer periphery of the inner pin 58 of the external gear 51 is formed in the flange portion 57 of the output carrier 53.

  An operation example of the above-described sheave drive device will be described.

When the electric motor 20 is operated, the rotor 24 of the electric motor 20 rotates, and the eccentric shaft portion 50 of the speed reducer 23 rotates together with the rotor 24. When the eccentric shaft portion 50 rotates, the external gear 51 has the center of the external gear 51 (that is, the center O ₂ of the outer periphery of the eccentric shaft portion 50) around the rotation center O ₁ of the eccentric shaft portion 50. The shaft rotates around the center of the external gear 51 (that is, the center O ₂ of the outer periphery of the eccentric shaft portion 50) by meshing the outer pin 55 and the external gear 51 while revolving so as to rotate at the same speed. It rotates at a speed slower than the rotation of the portion 50 (specifically, the speed at which the external gear 51 moves in the circumferential direction by one tooth of the external tooth 54 each time it revolves once). At this time, the rotation direction of the external gear 51 is opposite to the rotation direction of the eccentric shaft portion 50. When the external gear 51 rotates while revolving, the output carrier 53 extracts only the rotation of the external gear 51 by the contact between the inner pin 58 and the pin hole 59 and transmits it to the nut 21. In this way, the speed reducer 23 transmits the rotation of the electric motor 20 to the nut 21 through the speed reducer 23. When the nut 21 rotates, the screw shaft 22 moves in the axial direction by screw engagement between the nut 21 and the screw shaft 22, and at this time, the movable sheave 3 moves in the axial direction integrally with the screw shaft 22. As a result, the interval between the fixed sheave 2 and the movable sheave 3 changes, and the winding radius of the V-belt 9 wound between the opposed surfaces 7 and 8 of the fixed sheave 2 and the movable sheave 3 changes.

  This sheave drive device uses a hollow annular electric motor 20 for rotationally driving the nut 21 and has a configuration in which the pulley shaft 1 is passed through the hollow annular electric motor 20. The dead space is small. In addition, since the nut 21 is disposed radially inside the hollow annular electric motor 20 and radially outside the pulley shaft 1, the installation space for the electric motor 20 and the nut 21 is short in the axial direction. Therefore, this sheave drive device is compact and has excellent mountability on a vehicle.

  In addition, since the sheave drive device uses a hollow ring as the speed reducer 23 that decelerates the rotation of the electric motor 20 and transmits it to the nut 21, the dead space around the pulley shaft 1 is effectively reduced. It is possible. In addition, since the electric motor 20 rotationally drives the nut 21 via the speed reducer 23, the electric motor 20 necessary for moving the movable sheave 3 in the axial direction is more than when the electric motor 20 directly rotates the nut 21. Therefore, the sheave driving device can be effectively made compact.

  Further, in this sheave drive device, the speed reducer 23 is disposed so as to be adjacent to the electric motor 20 in the axial direction and positioned on the outer diameter side of the nut 21. Compared with the case where the speed reducer 23 is incorporated between the outer diameters of the nuts 21, the increase in the diameter of the sheave drive device can be suppressed, and the sheave drive device can be effectively made compact.

  Further, this sheave drive device employs a speed reducer 23 (cycloid speed reducer) that can obtain a large reduction ratio in a small space, so that the sheave drive device can be made particularly compact. It has become.

  The sheave driving device employs a configuration constituted by a plurality of outer pins 55 fixed to the motor housing 26 as the internal gear 52 of the speed reducer 23. That is, since the motor housing 26 of the electric motor 20 also serves as a member for fixing the outer pin 55 of the speed reducer 23, the number of parts of the speed reducer 23 can be suppressed, and the speed reducer 23 can be made compact. Is possible. Further, since the outer pin 55 is formed integrally with the motor housing 26 without any joint, the rigidity of the outer pin 55 can be secured by utilizing the rigidity of the motor housing 26, and the reduction gear 23 is particularly effective. It is possible to make it compact.

  In the above embodiment, as the nut 21 and the screw shaft 22 that are screw-engaged with each other, the ball 37 incorporated in the nut 21 rolls into contact with the screw groove formed on the outer periphery of the screw shaft 22 and the nut 21 of the ball screw mechanism. Although the screw shaft 22 has been described as an example, instead of this, a sliding screw mechanism (for example, a trapezoidal screw) in which a female screw formed on the inner periphery of the nut 21 is in sliding contact with a male screw formed on the outer periphery of the screw shaft 22. It is also possible to employ the nut 21 and the screw shaft 22 of FIG.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

Reference Signs List 1 pulley shaft 2 fixed sheave 3 movable sheave 4 electric linear actuator 20 electric motor 21 nut 22 screw shaft 23 speed reducer 24 rotor 25 stator 26 motor housing 43 spacer 44 thrust bearing 50 eccentric shaft portion 51 external gear 52 internal gear Gear 53 Output carrier 55 Outer pin O ₁ Rotation center O ₂ Center of outer periphery of eccentric shaft

Claims (8)

Pulley shaft (1);
A fixed sheave (2) provided fixed to the outer periphery of the pulley shaft (1);
It is arranged on the outer periphery of the pulley shaft (1) so as to face the fixed sheave (2) in the axial direction, and moves in the axial direction with respect to the pulley shaft (1) in a state in which the pulley shaft (1) is prevented from rotating. A movable sheave (3) supported in a possible manner;
A sheave drive device for a continuously variable transmission having an electric linear actuator (4) for moving the movable sheave (3) in the axial direction;
The electric linear actuator (4)
An electric motor (20) configured in a hollow annular shape through which the pulley shaft (1) passes;
A nut that is arranged coaxially with the electric motor (20) on the radially inner side of the hollow annular electric motor (20) and on the radially outer side of the pulley shaft (1), and is rotated by the electric motor (20) ( 21) and
A hollow screw shaft (22) that is screw-engaged with the nut (21) and moves in the axial direction integrally with the movable sheave (3) by rotation of the nut (21);
A sheave drive device for a continuously variable transmission.   Further comprising a hollow annular speed reducer (23) through which the pulley shaft (1) passes, the speed reducer (23) decelerates the rotation of the electric motor (20) and transmits it to the nut (21). Item 2. A sheave drive device for a continuously variable transmission according to item 1.   The continuously variable transmission according to claim 2, wherein the speed reducer (23) is disposed so as to be adjacent to the electric motor (20) in the axial direction and on an outer diameter side of the nut (21). Machine sheave drive. The speed reducer (23)
An eccentric shaft portion (50) having a cylindrical outer periphery that is eccentric from the center of rotation (O ₁ ), the rotation of the electric motor (20) being input;
An external gear (51) rotatably supported on the outer periphery of the eccentric shaft portion (50);
An internal gear that meshes with the external gear (51) so that when the eccentric shaft portion (50) rotates, the external gear (51) rotates at a speed slower than the rotation of the eccentric shaft portion (50). (52)
An output carrier (53) for taking out rotation of the external gear (51) and transmitting it to the nut (21);
The sheave drive device for a continuously variable transmission according to claim 2 or 3, wherein: The electric motor (20)
A hollow cylindrical rotor (24) disposed opposite the outer periphery of the nut (21);
An annular stator (25) for applying a rotational force to the rotor (24);
A motor housing (26) for accommodating the stator (25);
The internal gear (52) is composed of a plurality of external pins (55) provided fixed to the motor housing (26).
A sheave drive device for a continuously variable transmission according to claim 4.   The sheave drive device for a continuously variable transmission according to claim 5, wherein the outer pin (55) is formed integrally with the motor housing (26) without a joint.   A spacer (43) facing the movable sheave (3) in the axial direction is fixed to an end of the screw shaft (22) on the side close to the movable sheave (3), and the spacer (43) and the movable The thrust bearing (44) for supporting an axial load acting between the screw shaft (22) and the movable sheave (3) is incorporated between opposing surfaces of the sheave (3). A sheave drive device for a continuously variable transmission according to any one of the above.   The sheave drive device for a continuously variable transmission according to claim 7, wherein the thrust bearing (44) is a needle roller with a cage having needle rollers that are in direct contact with the movable sheave (3).

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