JP5779073B2 - Continuously variable transmission - Google Patents

Description

  The present invention relates to a continuously variable transmission.

  Conventionally, Patent Document 1 discloses a continuously variable transmission that includes a fixed pulley and a movable pulley and changes the width of a V-groove formed between the fixed pulley and the movable pulley to change speed. In the continuously variable transmission disclosed in Patent Document 1, a spring is provided on the back side of the movable pulley, and the V belt is held by the pulley by the biasing force of the spring.

JP 2009-168080 A

  However, in the above invention, when the spring is set so that belt slip does not occur between the pulley and the V belt when the width of the V groove is small, the biasing force by the spring is excessive when the width of the V groove becomes wide. Thus, there is a problem that the belt clamping force becomes excessive and the pulley or the V belt deteriorates.

  The present invention has been invented to solve such problems, and it is an object of the present invention to prevent the belt clamping force by the spring from becoming excessive and to suppress the deterioration of the pulley or the V-belt. .

A continuously variable transmission according to an aspect of the present invention includes a fixed pulley, a movable pulley that moves in an axial direction of a shaft portion to which the fixed pulley is connected, and a groove width of a V groove formed by the fixed pulley and the movable pulley. Is a continuously variable transmission provided with a fixed pulley and a belt whose contact radius with the movable pulley is changed, and elastic means for generating a thrust for urging the movable pulley toward the fixed pulley; And a thrust reduction mechanism that suppresses an increase in thrust by the elastic means when the movable pulley moves in the axial direction of the shaft so that the groove width of the V-groove becomes large. A first stopper which is provided on a shaft portion on the back surface side of the elastic means, and which is in contact with one end of the elastic means, is on the fixed pulley side with respect to the first stopper, is provided on the back side of the movable pulley, and contact, mosquitoes end of When the mechanically engages the pulley, and a transmitting means for transmitting mechanical constantly thrust by the elastic means on the movable pulley, the movable pulley as the groove width of the V groove is increased to move in the axial direction, The contact portion between the transmission means and the elastic means moves relative to the movable pulley toward the fixed pulley.

  According to this aspect, when the movable pulley moves in the axial direction so that the groove width of the V-groove becomes large, the transmission means with which the elastic means abuts moves toward the fixed pulley relative to the movable pulley. It is possible to prevent the belt clamping force from becoming excessive, and to suppress deterioration of the belt or the pulley.

It is a schematic sectional drawing of the continuously variable transmission of 1st Embodiment. It is the schematic in the II-II cross section of FIG. It is a schematic block diagram of the secondary pulley in the III-III cross section of FIG. It is the schematic which shows the protrusion part of 1st Embodiment. It is the schematic at the time of expand | deploying the protrusion part of 1st Embodiment. It is a figure which shows the modification of a protrusion part. It is a figure which shows the modification of a protrusion part. It is a figure which shows the modification of a protrusion part. It is a figure which shows the modification of a protrusion part. It is a schematic sectional drawing of the secondary pulley of 2nd Embodiment. It is a schematic sectional drawing of the secondary pulley of 3rd Embodiment.

  A continuously variable transmission according to a first embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a schematic sectional view of a continuously variable transmission according to this embodiment. The secondary pulley in FIG. 1 shows a state in which the gear ratio of the continuously variable transmission is at the highest level and a state at which it is the lowest level. FIG. 2 is a schematic view taken along the line II-II in FIG. FIG. 2 shows a state in which the gear ratio of the continuously variable transmission is at the lowest level.

  The continuously variable transmission 1 according to this embodiment includes a primary pulley 2, a secondary pulley 3, a belt 4, a spring 5, and a thrust reduction mechanism 6.

  The primary pulley 2 includes a fixed pulley 2a, a movable pulley 2b disposed to face the fixed pulley 2a, and a shaft portion 2c. The primary pulley 2 forms a V-shaped pulley groove by the sheave surface of the fixed pulley 2a and the sheave surface of the movable pulley 2b. The movable pulley 2b is moved along the shaft portion 2c by, for example, a centrifugal roller, and changes the groove width of the pulley groove.

  The secondary pulley 3 includes a fixed pulley 3a, a movable pulley 3b disposed to face the fixed pulley 3a, and a shaft portion 3c. The secondary pulley 3 forms a V-shaped pulley groove by the sheave surface of the fixed pulley 3a and the sheave surface of the movable pulley 3b. The movable pulley 3b is arranged so as to rotate together with the shaft portion 3c in the circumferential direction and to be movable with respect to the shaft portion 3c in the axial direction.

  The movable pulley 3b is in sliding contact with the shaft portion 3c and extends from the outer peripheral end of the movable pulley 3b in the radial direction to the opposite side of the fixed pulley 3a. A second cylindrical portion 7b that extends and a holding portion 7d that protrudes radially outward from the outer peripheral wall of the first cylindrical portion 7a are provided.

  A cutout portion 7c is formed in the first cylindrical portion 7a from the end opposite to the fixed pulley 3a toward the fixed pulley 3a. The notch portion 7c is formed so that the first cylindrical portion 7a does not come into contact with a protruding portion 10 to be described later when the movable pulley 3b moves in the axial direction. As shown in FIG. 3, the holding portion 7 d is disposed so as to sandwich a carrier 14 described later in the axial direction, and restricts movement of the carrier 14 in the axial direction. FIG. 3 is a schematic diagram of the secondary pulley 3 in the III-III cross section of FIG. 2, and shows a state where the gear ratio is the highest and a state where the gear ratio is the lowest. The holding part 7d does not restrict the rotation of the carrier 14 in the circumferential direction.

  The movable pulley 3b moves along the axial direction of the shaft portion 3c by the difference between the force that pushes the movable pulley 3b to the opposite side of the fixed pulley 3a by the belt 4 and the force that pushes the movable pulley 3b to the fixed pulley 3a side by the spring 5. Change the pulley groove width.

  In the secondary pulley 3, the belt clamping force is generated by the thrust that pushes the movable pulley 3 b toward the fixed pulley 3 a by the spring 5.

  The belt 4 is wound between the primary pulley 2 and the secondary pulley 3, and transmits power between the primary pulley 2 and the secondary pulley 3. The continuously variable transmission 1 changes the gear ratio steplessly by changing the contact radius between the primary pulley 2 and the belt 4 and the contact radius between the secondary pulley 3 and the belt 4.

  The thrust reduction mechanism 6 is a planetary gear mechanism including a protruding portion 10, a sun gear 11, a pinion gear 12, a ring gear 13, a carrier 14, a third cylindrical portion 15, and a stopper 16.

  The protruding portion 10 is provided on the shaft portion 3c on the back side of the movable pulley 3b, protrudes radially outward from the shaft portion 3c, and extends in the axial direction. The protruding portion 10 is formed in a spiral shape as shown in FIG. When the protruding portion 10 is developed on a plane, the protruding portion 10 has a linear shape inclined with respect to the shaft 3d of the shaft portion 3c as shown in FIG. The back surface of the movable pulley 3b refers to the back surface of the surface facing the fixed pulley 3a.

  The 3rd cylindrical part 15 is provided in the radial direction outer side rather than the protrusion part 10, and is extended in the axial direction. The end of the third cylindrical portion 15 on the fixed pulley 3a side is connected to the back surface of the movable pulley 3b. A first groove 15 a into which the sun gear 11 is screwed is formed in a spiral shape on the outer peripheral wall of the third cylindrical portion 15. The first groove 15a is formed such that when the movable pulley 3b moves in the axial direction so that the width of the pulley groove of the secondary pulley 3 increases, the sun gear 11 moves toward the fixed pulley 3a while rotating in the circumferential direction. Is done.

  The sun gear 11 is an external gear having a radially inner end screwed into the first groove 15a of the third cylindrical portion 15 and a gear formed on the radially outer side. The sun gear 11 is rotatable along the first groove 15 a and meshes with the gear of the pinion gear 12. The sun gear 11 can move in the axial direction while meshing with the gear of the pinion gear 12. The sun gear 11 contacts the end of the spring 5 on the fixed pulley 3a side, transmits the elastic force of the spring 5 to the movable pulley 3b, and biases the movable pulley 3b toward the fixed pulley 3a.

  The pinion gear 12 meshes with the gear of the sun gear 11 on the radially inner side, and meshes with the gear of the ring gear 13 on the radially outer side. The pinion gear 12 is restricted from moving in the radial direction by the carrier 14 and revolves in the circumferential direction together with the carrier 14. Further, the pinion gear 12 rotates around the shaft portion 14 b of the carrier 14. The pinion gear 12 is provided so as to extend in the axial direction so that the sun gear 11 can move in the axial direction in a state where the pinion gear 12 and the sun gear 11 are engaged with each other.

  The carrier 14 includes a screwing portion 14 a that extends in the axial direction on the radially inner side, and a shaft portion 14 b that pivotally supports the pinion gear 12. The threaded portion 14a is provided between the first cylindrical portion 7a and the third cylindrical portion 15 of the movable pulley 3b, and a second groove 14c that is threadedly engaged with the protruding portion 10 is formed. The second groove 14 c is formed in a spiral shape along the shape of the protruding portion 10. The carrier 14 is restricted from moving in the axial direction by the holding portion 7d, and moves with the movable pulley 3b in the axial direction. However, the rotation in the circumferential direction is not restricted by the holding portion 7d, and the carrier 14 is rotatable relative to the movable pulley 3b. When the carrier 14 moves in the axial direction together with the movable pulley 3b, the carrier 14 rotates in the circumferential direction along the protruding portion 10. That is, when the carrier 14 moves in the axial direction, the carrier 14 rotates in the circumferential direction relative to the shaft portion 3c and the movable pulley 3b.

  The ring gear 13 is an internal gear that is provided on the inner peripheral wall of the second cylindrical portion 7 b of the movable pulley 3 b and meshes with the pinion gear 12. The ring gear 13 rotates together with the movable pulley 3b. When the movable pulley 3b moves in the axial direction, the carrier 14 also rotates relative to the ring gear 13 in the circumferential direction.

  The stopper 16 is provided on the back side of the movable pulley 3b, and protrudes radially outward from the shaft portion 3c. The stopper 16 abuts the end of the spring 5 opposite to the end abutting the sun gear 11.

  The spring 5 has one end abutting against the sun gear 11 and the other end abutting against the stopper 16 to generate a thrust force that urges the sun gear 11 toward the fixed pulley 3a, and the fixed pulley 3a and the movable pulley 3b. Thus, a belt clamping force for holding the belt 4 is generated. The spring 5 is set so as to generate a belt clamping force that does not cause belt slip when the speed ratio is the lowest.

  The operation of this embodiment will be described.

  When the gear ratio of the continuously variable transmission 1 is changed to the High side, the movable pulley 3b moves in the axial direction so that the width of the pulley groove of the movable pulley 3b is increased. When the movable pulley 3b moves in the axial direction, the carrier 14 rotates in the circumferential direction along the protruding portion 10. The carrier 14 rotates in the circumferential direction relative to the movable pulley 3b. The ring gear 13 is fixed to the movable pulley 3b. When the carrier 14 rotates in the circumferential direction, the pinion gear 12 rotates and the sun gear 11 also rotates. The radially inner end of the sun gear 11 is screwed into the first groove 15a of the third cylindrical portion 15 fixed to the movable pulley 3b. Therefore, the sun gear 11 moves along the first groove 15a and moves toward the fixed pulley 3a while rotating in the circumferential direction.

  That is, when the movable pulley 3b moves in the axial direction so that the width of the pulley groove becomes wider, the sun gear 11 moves in the direction opposite to the moving direction of the movable pulley 3b in the axial direction. One end of the spring 5 is in contact with the sun gear 11, and the other end of the spring 5 is in contact with the stopper 16. Therefore, when the movable pulley 3b moves in the axial direction so that the width of the pulley groove becomes wider, the length of the spring 5 becomes longer and the thrust of the movable pulley 3b by the spring 5 becomes smaller.

  Moreover, the rotational speed output by the sun gear 11 is increased with respect to the rotational speed input via the carrier 14 by the planetary gear mechanism, and the thrust reduction mechanism 6 has a function as a speed increasing mechanism.

  The effect of 1st Embodiment of this invention is demonstrated.

  When the movable pulley 3b moves in the axial direction so that the width of the pulley groove of the secondary pulley 3 is increased, a thrust reduction mechanism 6 is provided that reduces the thrust that the spring 5 biases the movable pulley 3b toward the fixed pulley 3a. . One end of the spring 5 abuts on a stopper 16 provided on the shaft portion 3 c of the secondary pulley 3, and the other end of the spring 5 abuts on the sun gear 11. When the movable pulley 3b moves in the axial direction so that the width of the pulley groove of the secondary pulley 3 increases, the sun gear 11 moves relative to the movable pulley 3b toward the fixed pulley 3a. As a result, when the movable pulley 3b moves in the axial direction so that the width of the pulley groove of the secondary pulley 3 is increased, an increase in thrust for urging the movable pulley 3b toward the fixed pulley 3a by the spring 5 is prevented. can do. For example, when the required belt clamping force is large when the gear ratio is low, the spring 5 is set according to the required belt clamping force, and when the gear ratio is high, the belt is clamped. It is possible to prevent the force from becoming excessive. Therefore, it is possible to suppress a decrease in durability of the belt or the secondary pulley 3 when the gear ratio is on the High side (effect corresponding to claim 1).

  When the movable pulley moves in the axial direction so that the width of the pulley groove of the secondary pulley is increased without using this embodiment, the belt is clamped by moving the spring and stopper in the same direction as the moving direction of the movable pulley. Although it is possible to prevent the force from becoming excessive, a space for moving the spring and the stopper is required in the axial direction, and the length in the axial direction becomes long. In this embodiment, when the movable pulley 3b moves in the axial direction so that the width of the pulley groove of the secondary pulley 3 is increased, the sun gear 11 is moved toward the fixed pulley 3a relative to the movable pulley 3b. Therefore, it is not necessary to provide a space necessary for moving the spring 5 and the stopper 16, the axial length of the continuously variable transmission 1 can be shortened, and the continuously variable transmission 1 can be downsized. Yes (effect corresponding to claim 1).

  A spiral projecting portion 10 is provided on the shaft portion 3 c, and a second groove 14 c that is threadedly engaged with the projecting portion 10 is formed in the threaded portion 14 a of the carrier 14. The sun gear 11 meshes with the pinion gear 12 so as to be movable in the axial direction. Thereby, when the movable pulley 3b moves in the axial direction, the carrier 14 and the pinion gear 12 rotate in the circumferential direction, and the sun gear 11 rotates in the circumferential direction along the first groove 15a and moves in the axial direction. . In this way, when the movable pulley 3b moves in the axial direction so that the width of the pulley groove of the secondary pulley 3 is increased, the sun gear 11 is moved toward the fixed pulley 3a relative to the movable pulley 3b by a mechanical mechanism. It can be moved (effect corresponding to claim 2).

  By accelerating the rotation of the carrier 14 in the circumferential direction and transmitting it to the sun gear 11, the amount of movement of the sun gear 11 in the axial direction relative to the amount of movement of the movable pulley 3b in the axial direction can be increased, and the belt is clamped. It is possible to further prevent the force from becoming excessive (effect corresponding to claim 3).

  The thrust reduction mechanism 6 is a planetary gear mechanism, particularly a single pinion planetary gear mechanism, the pinion gear 12 meshes with a ring gear 13 fixed to the movable pulley 3b, and the sun gear 11 is screwed into a third groove 15c fixed to the movable pulley 3b. Match. As a result, when the movable pulley moves in the axial direction so that the width of the pulley groove of the secondary pulley is increased, the sun gear 11 is moved relative to the movement of the movable pulley 3b in the axial direction by a mechanical mechanism having a small number of parts. Can be moved to the fixed pulley 3a side (effect corresponding to claims 4 and 5).

  When the protruding portion 10 is deployed, the width of the pulley groove of the secondary pulley 3 is increased by providing the protruding portion 10 so that the protruding portion 10 has a linear shape inclined with respect to the axis 3d of the shaft portion 3c. When the movable pulley 3b moves in the axial direction, the belt clamping force can be reduced according to the amount of movement of the movable pulley 3b in the axial direction (effect corresponding to claim 6).

  In the present embodiment, the protrusion 10 has a linear shape when deployed as shown in FIG. 5, but may have the shape shown in FIGS. 6 and 7. FIG. 6 is a modified example of the protrusion, and FIG. 7 is a development view of the protrusion 20 of FIG. When the protrusion 20 is developed, the protrusion 20 has a curved shape. As a result, in the developed view, the reduction amount of the belt clamping force is small when the gear ratio is low, and the belt clamping force is low when the gear ratio is high, as compared to the case where the protrusion has a linear shape. The amount of reduction increases.

  Moreover, the further modification of a protrusion part is shown to FIG. FIG. 8 is a modified example of the protruding portion, and FIG. 9 is a development view of the protruding portion 21 of FIG. When the protrusion 21 is developed, the protrusion 21 has a shape in which a plurality of linear protrusions having different inclinations are connected. Thereby, the reduction amount of belt clamping force can be adjusted according to the shape of the protrusion part 21. FIG.

  Next, a continuously variable transmission according to a second embodiment of the present invention will be described with reference to FIG. FIG. 10 is a schematic cross-sectional view of the secondary pulley of the present embodiment. FIG. 10 shows a state in which the gear ratio of the continuously variable transmission is at the highest level and a state at which it is the lowest level.

  The present embodiment is mainly different from the first embodiment in the thrust reduction mechanism. The second embodiment will be described with a focus on differences from the first embodiment. The same configurations as those of the first embodiment are denoted by the same reference numerals as those of the first embodiment, and description thereof is omitted here.

  The thrust reduction mechanism 40 is a planetary mechanism including the protruding portion 10, the sun gear 41, the pinion gear 12, the ring gear 42, the carrier 43, the third cylindrical portion 44, and the stopper 16.

  The sun gear 41 is an external gear connected to the outer peripheral wall of the third cylindrical portion 44 fixed to the movable pulley 30.

  The ring gear 42 is an internal gear that meshes with the pinion gear 12, and the outer peripheral end portion of the ring gear 42 is screwed into the third groove 32 provided in the second cylindrical portion 31 of the movable pulley 30.

  One end of the spring 5 is in contact with the stopper 16, and the other end is in contact with the ring gear 42.

  The operation of this embodiment will be described.

  When the movable pulley 30 moves in the axial direction so that the width of the pulley groove becomes wider, the carrier 43 rotates in the circumferential direction along the protruding portion 10. The sun gear 41 is fixed to the movable pulley 30, and the pinion gear 12 rotates and the ring gear 42 also rotates due to the rotation of the carrier 43 in the circumferential direction. A radially outer end of the ring gear 42 is screwed into a third groove 32 formed in the second cylindrical portion 31 of the movable pulley 30. Therefore, the ring gear 42 moves along the third groove 32 and moves toward the fixed pulley 3a while rotating in the circumferential direction.

  In the present embodiment, when the movable pulley 30 moves in the axial direction so that the width of the pulley groove becomes wider, the ring gear 42 moves in the direction opposite to the moving direction of the movable pulley 30 in the axial direction.

  The effect of 2nd Embodiment of this invention is demonstrated.

  In this embodiment, compared to the first embodiment, the amount of movement of the ring gear 42 relative to the amount of movement of the movable pulley 30 in the axial direction can be reduced, and the amount of reduction force of the belt clamping force can be reduced. . That is, by adopting the configuration of the first embodiment and the second embodiment, the configuration of the planetary gear mechanism, the shape of the protruding portion 10, and the number of gear teeth are combined with the amount of movement of the movable pulley 3b in the axial direction. Thereby, the freedom degree of the belt clamping force with respect to the moving amount | distance to the axial direction of the movable pulley 3b can be increased.

  A continuously variable transmission according to a third embodiment of the present invention will be described with reference to FIG. FIG. 11 is a schematic configuration diagram of the secondary pulley of the present embodiment, showing a case where the gear ratio of the continuously variable transmission is the highest and a case where the gear ratio is the lowest.

  In the continuously variable transmission according to the present embodiment, the third embodiment will be described with a focus on differences from the first embodiment. The same configurations as those of the first embodiment are denoted by the same reference numerals as those of the first embodiment, and description thereof is omitted here.

  The thrust reduction mechanism 50 includes a first stopper 51, a second stopper 52, a rotating part 53, and a connecting part 54.

  The first stopper 51 protrudes radially outward from the shaft portion 3c. One end of the spring 55 contacts the first stopper 51.

  The second stopper 52 is located closer to the movable pulley 60 than the first stopper 51 and protrudes radially outward. The second stopper 52 comes into contact with a part of the rotating portion 53. The distance between the first stopper 51 and the second stopper 52 does not change even when the movable pulley 60 moves in the axial direction.

  The rotating portion 53 is connected to the inner peripheral wall of the second cylindrical portion 61 of the movable pulley 60 via the connecting portion 54 and rotates around the connecting portion 54. The rotating portion 53 contacts the second stopper 52 and the spring 55 on the radially inner end side. The second stopper 52, the rotating part 53, and the spring 55 are arranged in the order of the second stopper 52, the rotating part 53, and the spring 55 from the fixed pulley 3a side. In other words, the rotating portion 53 has a surface or end on the side of the fixed pulley 3 a in contact with the second stopper 52 and a surface on the opposite side in contact with the spring 55 in the vicinity of the radially inner end.

  The operation of this embodiment will be described.

  When the gear ratio is at the lowest level, that is, when the width of the pulley groove of the movable pulley 60 is the minimum, the first stopper 51 and the rotating portion 53 are substantially parallel. When the gear ratio is changed to the High side and the movable pulley 60 moves in the axial direction so that the width of the pulley groove of the movable pulley 60 is increased, the connecting portion 54 moves in the axial direction together with the movable pulley 60. Since the rotating part 53 is urged toward the fixed pulley 3 a by the spring 55, the rotating part 53 rotates around the connecting part 54. The radially inner end of the rotating part 53 is in contact with the second stopper 52, and the radially inner end of the rotating part 53 moves to the fixed pulley 3 a side with respect to the second stopper 52. Absent. When the movable pulley 60 moves in the axial direction in this way, the rotating portion 53 rotates and the contraction of the spring 55 can be reduced.

  The urging force by the spring 55 acts on the movable pulley 60 via the rotating portion 53 and the connecting portion 54, and the movable pulley 60 clamps the belt 4 by this urging force. Therefore, the belt clamping force by the spring 55 increases as the contact portion between the spring 55 and the rotating portion 53 becomes radially outward, that is, the connecting portion 54 side. Even if the position of the movable pulley 60 is the same, the belt clamping force by the spring 55 is different by changing the contact position between the spring 55 and the rotating portion 53. That is, the belt clamping force can be changed by changing the contact position between the spring 55 and the rotating portion 53.

  The effect of the third embodiment of the present invention will be described.

  The rotating part 53 is rotatable via a connecting part 54 connected to the movable pulley 60, and the end part on the radially inner side comes into contact with the second stopper 52 provided on the shaft part 3c. When the movable pulley 60 moves in the axial direction so that the pulley groove becomes larger, the rotating portion 63 rotates via the connecting portion 54, and the movable pulley 60 is moved to the fixed pulley 3a side via the rotating portion 63. It is possible to reduce the contraction of the spring 55 that biases the spring. Therefore, when the movable pulley 60 moves in the axial direction so that the width of the pulley groove is increased, it is possible to suppress an increase in the thrust that urges the movable pulley 60 toward the fixed pulley 3a by the spring 55 ( (The effect corresponding to claim 9).

  It goes without saying that the present invention is not limited to the above-described embodiments, and includes various modifications and improvements that can be made within the scope of the technical idea.

  In the above embodiment, a single pinion planetary gear mechanism is used as the thrust reduction mechanism 6, but a double pinion planetary gear mechanism may be used. By using the double pinion planetary gear mechanism, the speed of rotation of the carrier can be increased.

  In the above embodiment, two holding portions 7d are provided in the horizontal direction in FIG. 2, but the number and arrangement of the holding portions 7d are not limited to the above embodiment.

DESCRIPTION OF SYMBOLS 1 Continuously variable transmission 3a Fixed pulley 3b, 30 Movable pulley 3c Shaft part 4 Belt 5, 55 Spring (elastic means)
6, 40, 50 Thrust reduction mechanism 10 Projection (first screwing means)
11 Sun gear (transmission means)
12 Pinion gear (second screwing means)
13 Ring gear 14, 43 Carrier (second screwing means)
15 3rd cylindrical part (3rd screwing means)
16 Stopper (first stopper)
42 Ring gear (transmission means)
51 First stopper 52 Second stopper 53 Rotating part (transmission means)
54 connection

Claims (9)

The fixed pulley, the movable pulley that moves in the axial direction of the shaft portion to which the fixed pulley is connected, and the groove width of the V groove formed by the fixed pulley and the movable pulley are changed, thereby the fixed pulley. And a continuously variable transmission comprising a belt whose contact radius with the movable pulley is changed,
Elastic means for generating a thrust for urging the movable pulley toward the fixed pulley;
A thrust reduction mechanism that suppresses an increase in thrust by the elastic means when the movable pulley moves in the axial direction of the shaft portion so that the groove width of the V groove increases.
The thrust reduction mechanism is
A first stopper provided on the shaft portion on the back side of the movable pulley, with which one end of the elastic means contacts;
The fixed pulley side of the first stopper, provided on the back side of the movable pulley, the other end of the elastic means abuts, mechanically engages the movable pulley, and the elastic means Transmission means for mechanically transmitting the thrust force by the mechanical pulley to the movable pulley at all times ,
When the movable pulley moves in the axial direction so that the groove width of the V-groove becomes large, the contact portion between the transmission means and the elastic means is relatively fixed to the movable pulley. A continuously variable transmission that moves to the side. The thrust reduction mechanism is
A helical first screwing means formed on the shaft on the back side of the movable pulley;
A second screwing means that is screwed into the first screwing means and rotates the transmission means in the circumferential direction of the shaft portion;
The transmission means is configured to rotate the movable pulley while rotating in the circumferential direction by the second screwing means when the movable pulley moves in the axial direction of the shaft portion so that the groove width of the V groove increases. The continuously variable transmission according to claim 1, wherein the continuously variable transmission moves relative to the fixed pulley side.   3. The continuously variable transmission according to claim 2, wherein the thrust reduction mechanism is a speed increasing mechanism that speeds up rotation by the first screwing means and transmits the speed to the transmitting means.   The continuously variable transmission according to claim 3, wherein the speed increasing mechanism is a planetary gear mechanism. The speed increasing mechanism is a single pinion planetary gear mechanism,
The second screwing means is constituted by a carrier and a pinion gear,
The transmission means is a sun gear meshing with the pinion gear;
The single pinion planetary gear mechanism is
A ring gear meshing with the pinion gear and fixed to the movable pulley;
Screwed with the radially inner end of the sun gear and provided with a helical third screwing means fixed to the movable pulley;
The carrier and the pinion gear move along the spiral shape of the first screwing means,
The continuously variable transmission according to claim 4, wherein the sun gear moves along a spiral shape of the third screwing means.   The continuously variable transmission according to any one of claims 2 to 5, wherein the first screwing means has a linear shape inclined with respect to the axis of the shaft portion when deployed in a plane. .   The continuously variable transmission according to any one of claims 2 to 5, wherein the first screwing means has a curved shape when deployed in a plane.   The said 1st screwing means becomes a shape which inclined with respect to the axis line of the said axial part when expand | deployed on a plane, and became a shape which connected several linear shape from which inclination differs. A continuously variable transmission according to claim 1. The thrust reduction mechanism is
A second stopper provided on the shaft on the back side of the movable pulley, and provided on the fixed pulley side of the first stopper;
Connecting means for rotatably connecting one end of the transmission means to the movable pulley;
2. The continuously variable transmission according to claim 1, wherein the other end of the transmission means is in contact with the second stopper.

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