JP2017096406A - Belt-type continuously variable transmission - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a belt-type continuously variable transmission which can effectively suppress damage of a case even when a chain belt is fractured during driving.SOLUTION: A torsion coil spring 12 for rotating a guide rail 8 in one rotation direction is arranged at the guide rail 8 which suppresses vibration of a chain belt 6 for transmitting power between pulleys 3, 5, a guide stopper 13 for stopping rotation by being engaged with the guide rail 8 when the guide rail 8 is rotated by receiving an elastic force of the torsion coil spring 12 is formed at a case 7, and a reinforcement part 15 for enhancing strength higher than that in the other portion is formed in a prescribed range of the case 7 including a cross point P1 between an extension line extending in a longitudinal direction of the guide rail 8 and an inner wall face 7a of the case 7 in a state that the guide rail 8 and the guide stopper 13 are engaged with each other, and the rotation of the guide rail 8 is stopped.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a structure of a belt type continuously variable transmission, and particularly to a belt type continuously variable transmission that uses a chain belt for power transmission.

  Patent Document 1 describes an invention related to a belt-type continuously variable transmission. In the belt-type continuously variable transmission described in Patent Document 1, a chain belt is provided between an input pulley to which power output from a driving force source is input and an output pulley connected to the output side of a vehicle drive system. It is wrapped around. And it is comprised so that the rotational speed of a driving force source may be changed in a stepless manner by changing each groove width of an input pulley and an output pulley. Further, the belt type continuously variable transmission described in Patent Document 1 is provided with a guide rail for suppressing noise and vibration of the belt type continuously variable transmission. The guide rail is supported by the case so that the chain belt is slid to suppress the string vibration of the chain belt and can swing about the shaft.

JP2013-7438A

  In a belt-type continuously variable transmission using a chain belt as described in Patent Document 1 above, when the chain belt breaks during operation, the broken chain belt collides with the inner wall of the transmission case, May cause damage. If the location where the chain belt collides with the case can be known in advance, damage to the case due to the collision of the chain belt can be suppressed by reinforcing the location where the collision is predicted. However, in the belt-type continuously variable transmission described in Patent Document 1, it is not easy to predict where the broken chain belt collides with the case. When the chain belt breaks and collides with the case, it is considered that the chain belt slides in the guide rail for a certain period after breaking, that is, is guided by the guide rail and collides with the case from the broken portion. . In that case, in the belt-type continuously variable transmission described in Patent Document 1, since the guide rail is rotatable as described above, the guide rail freely swings when the chain belt is broken. Therefore, the direction in which the chain belt is guided by the guide rail is not constant. Therefore, it is difficult to predict where the broken chain belt will collide with the case.

  The present invention has been conceived by paying attention to the technical problems as described above, and is a belt type that can effectively suppress damage to the case even when the chain belt breaks during operation. An object of the present invention is to provide a continuously variable transmission.

  In order to achieve the above-described object, the present invention provides a power source between a primary pulley, a secondary pulley, and the primary pulley and the secondary pulley wound around pulley grooves of the primary pulley and the secondary pulley. A chain belt that transmits the guide belt, and a guide rail that suppresses vibration of the chain belt by contacting a string portion in which the chain belt linearly travels between the primary pulley and the secondary pulley, the primary pulley, A belt-type continuously variable transmission that includes a secondary pulley, the chain belt, and a case that houses the guide rail, and changes a gear ratio by changing a groove width of the pulley groove. The chain belt extends in the length direction of the part and slides. And a support portion that rotatably supports the guide portion, and is supported by the case so as to be able to rotate following a change in the inclination of the chord portion in the traveling direction accompanying the change in the transmission gear ratio. And at least one guide rail is provided with a spring member for applying an elastic force for rotating the guide rail in one rotational direction, and the case is rotated when the guide rail is rotated by the elastic force. A stopper portion that engages with the guide rail to stop the rotation of the guide rail is formed, and the guide rail and the stopper portion engage with each other to stop the rotation of the guide rail. From the other part not including the predetermined range in the predetermined range of the case including the intersection of the extension line extending in the longitudinal direction of the guide portion from the portion and the inner wall surface of the case It is characterized in that the reinforcing portion to increase the strength of the portion of said predetermined range is formed.

  According to this invention, the guide rail which suppresses the vibration of a chain belt is provided in the string part of a chain belt by contacting the string part. The guide rail is supported so as to be able to rotate following the change in the inclination of the string portion accompanying the speed change. In other words, the guide rail is restricted from swinging in the rotation direction of the guide rail by the string portion of the chain belt. Furthermore, the guide rail is urged in one of the rotational directions by the elastic force of the spring member. Therefore, when the chain belt is broken, the guide rail loses the restraining force by the string portion and rotates by the elastic force of the spring member. In this case, the stopper portion that engages with the guide rail is provided, so that the guide rail rotates once by the elastic force of the spring member, but the subsequent rotation is stopped by engaging with the stopper portion. And fixed in a state where a predetermined posture is maintained. Therefore, the broken chain belt travels along a guide rail fixed in a predetermined posture, and then collides with a certain place on the inner wall surface of the case. And the intensity | strength is raised more than the other part by the reinforcement part in the location where the broken chain belt collides with a case. Therefore, even if the chain belt breaks and collides with the case, damage to the case can be effectively suppressed.

It is a figure which shows an example of the belt type continuously variable transmission to which this invention is applied, Comprising: It is a figure for demonstrating the behavior at the time of the fracture | rupture of a chain belt. It is a figure which shows an example of the belt-type continuously variable transmission to which this invention is applied, Comprising: It is a figure for demonstrating the state at the time of the normal of a chain belt. It is a figure which shows the other example of the belt-type continuously variable transmission to which this invention is applied, Comprising: It is a figure for demonstrating the behavior at the time of the fracture | rupture of a chain belt.

  The present invention will be specifically described with reference to the drawings. The present invention can be applied to a conventional general belt-type continuously variable transmission that employs a chain belt as a transmission belt. For example, it can also be applied to a belt-type continuously variable transmission mounted on a vehicle as described in Patent Document 1 described above. 1 and 2 show the configuration of the main part of a belt type continuously variable transmission (hereinafter referred to as CVT) 1 to which the present invention is applied. 1 and 2 is an output member such as an input shaft 2 to which torque is transmitted from a power source (not shown), a primary pulley 3 that rotates integrally with the input shaft 2, and a drive shaft (not shown). An output shaft 4 that transmits torque to the output shaft 4, a secondary pulley 5 that rotates integrally with the output shaft 4, a pulley groove 3 a of the primary pulley 3, a chain belt 6 wound around the pulley groove 5 a of the secondary pulley 5, and a case 7. ing. The input shaft 2 and the output shaft 4 are arranged in parallel. The case 7 supports the input shaft 2 and the output shaft 4 described above, and houses the primary pulley 3, the secondary pulley 5, the chain belt 6, and the like.

  The primary pulley 3 is configured by arranging a fixed sheave and a movable sheave (not shown) to face each other. The fixed sheave is formed integrally with the input shaft 2. The movable sheave is attached to the input shaft 2 by, for example, a spline so that the movable sheave rotates integrally with the input shaft 2 and can move in the axial direction. By making the taper surface of the fixed sheave and the taper surface of the movable sheave face each other in the axial direction of the input shaft 2, a pulley groove 3a is formed between them. Further, the primary pulley 3 is provided with a hydraulic actuator (not shown) for moving the movable sheave in the axial direction.

  Similarly, the secondary pulley 5 is configured by arranging a fixed sheave and a movable sheave (not shown) to face each other. The fixed sheave is formed integrally with the output shaft 4. The movable sheave is attached to the output shaft 4 by, for example, a spline so as to rotate integrally with the output shaft 4 and to be movable in the axial direction. By making the tapered surface of the fixed sheave and the tapered surface of the movable sheave face each other in the axial direction of the output shaft 4, a pulley groove 5a is formed between them. The secondary pulley 5 is also provided with a hydraulic actuator (not shown) for moving the movable sheave in the axial direction.

  The chain belt 6 is a transmission belt that is wound around the pulley groove 3 a of the primary pulley 3 and the pulley groove 5 a of the secondary pulley 5 and transmits torque between the primary pulley 3 and the secondary pulley 5. The chain belt 6 is configured by, for example, connecting a plurality of links (not shown) in a ring shape with pins (not shown).

  As described above, the CVT 1 transmits torque between the primary pulley 3 and the secondary pulley 5, that is, between the input shaft 2 and the output shaft 4 by the chain belt 6. At the same time, the gear ratio is changed by changing the widths of the pulley groove 3a and the pulley groove 5a. For example, the gear ratio is changed by controlling the hydraulic actuator of the primary pulley 3 to change the groove width of the pulley groove 3a and changing the winding diameter of the chain belt 6 wound around the pulley groove 3a. That is, a shift is performed. In that case, on the secondary pulley 5 side, since the circumferential length of the chain belt 6 is constant, the groove width of the pulley groove 5a changes according to the change of the groove width of the pulley groove 3a. And in order to suppress the slip between the chain belt 6 and the secondary pulley 5, the hydraulic actuator of the secondary pulley 5 is controlled and the belt clamping pressure in the pulley groove 5a is maintained by the appropriate magnitude | size.

  Guide rails 8 and 9 are provided on the CVT 1. The guide rails 8 and 9 are members for suppressing the vibration of the chain belt 6 and are provided on the string portions 6 a and 6 b of the chain belt 6. The string portions 6 a and 6 b are portions where the chain belt 6 advances linearly between the primary pulley 3 and the secondary pulley 5. The guide rail 8 is provided on the string portion 6a that becomes the tension side (upper side in FIGS. 1 and 2), for example, when the primary pulley 3 rotates in the forward direction (clockwise direction in FIGS. 1 and 2). For example, the guide rail 9 is provided on the string portion 6b that is on the loose side (lower side in FIGS. 1 and 2) when the primary pulley 3 rotates in the forward direction. On the tension side, the tension of the chain belt 6 acting when the chain belt 6 advances is relatively large. On the other hand, on the loose side, the tension of the chain belt 6 acting when the chain belt 6 advances is relatively small.

  The guide rail 8 has a guide portion 8a and a support portion 8b. The guide portion 8a is a portion that extends in the length direction of the string portion 6a and the chain belt 6 slides or contacts in a state where the guide rail 8 is installed so as to cover the string portion 6a. The support portion 8b is integrated with the guide portion 8a, and a shaft or a shaft hole for being rotatably supported by the case 7 is formed. In the example shown in FIGS. 1 and 2, the guide rail 8 can be rotated to the case 7 by fitting a shaft hole (not shown) formed in the support portion 8 b into the shaft 10 fixed to the case 7. It is supported.

  Similarly, the guide rail 9 has a guide portion 9a and a support portion 9b. The guide portion 9a is a portion that extends in the length direction of the string portion 6b and the chain belt 6 slides or contacts in a state where the guide rail 9 is installed so as to cover the string portion 6b. The support portion 9b is integrated with the guide portion 9a, and a shaft or a shaft hole for being rotatably supported by the case 7 is formed. In the example shown in FIGS. 1 and 2, the guide rail 9 can be rotated to the case 7 by fitting a shaft hole (not shown) formed in the support portion 9 b into the shaft 11 fixed to the case 7. It is supported.

  By providing the guide rails 8 and 9 as described above, vibration and noise generated in the CVT 1 can be suppressed. For example, when the chain belt 6 vibrates with a predetermined amplitude such as meandering and undulation during the operation of the CVT 1, the chain belt 6 comes into contact with the guide rails 8 and 9, thereby suppressing the vibration of the chain belt 6. As a result, vibration and noise of CVT 1 are suppressed. Even if the chain belt 6 contacts the guide rails 8 and 9 during the travel, the guide rails 8 and 9 are rotatably supported as described above, so that the travel of the chain belt 6 is not hindered. On the other hand, although the guide rails 8 and 9 are rotatably supported, the guide portions 8a and 9a cover the string portions 6a and 6b of the chain belt 6, respectively. Therefore, the swinging of the guide rails 8 and 9 in the rotation direction is limited.

  Further, the CVT 1 is configured so that damage to the case 7 can be effectively suppressed even when the chain belt 6 is broken during operation. Specifically, at least one of the guide rails 8 and 9 is provided with a spring member for rotating the guide rail 8 (and / or 9) in a predetermined rotation direction. At the same time, when the guide rail 8 (and / or 9) is rotated by the elastic force of the spring member, a stopper portion is provided to stop the rotation. In the example shown in FIGS. 1 and 2, a torsion coil spring 12 is attached to the guide rail 8 as a spring member. Further, a guide stopper 13 that stops the rotation of the guide rail 8 by the torsion coil spring 12 is formed in the case 7 as a stopper portion.

  The torsion coil spring 12 uses the above-mentioned shaft 10 that rotatably supports the guide rail 8 as a guide rod, and a coil portion 12 a is fitted on the shaft 10. The torsion coil spring 12 is attached to the guide rail 8 with one arm portion 12b and the other arm portion 12c attached to a spring stopper 14 formed on the case 7 in a state where a load is applied in the direction in which the spring is wound. It has been. Therefore, the guide rail 8 is given an elastic force by the torsion coil spring 12 to rotate the guide rail 8 in one direction (clockwise in FIGS. 1 and 2).

  When the guide rail 8 is rotated by the elastic force of the torsion coil spring 12, the guide stopper 13 is positioned at a position where one end (left side in FIGS. 1 and 2) of the guide portion 8a is locked. 7 is formed integrally. Therefore, when the chain belt 6 is broken, the guide rail 8 loses the restraining force by the string portion 6 a and rotates by the elastic force of the torsion coil spring 12. In that case, by providing the guide stopper 13 as described above, the guide rail 8 is temporarily rotated and then stopped by the guide stopper 13, and the predetermined posture is maintained as shown in FIG. It is fixed with.

  In this CVT 1, it is predicted that the broken chain belt 6 is released from the primary pulley 3 or the secondary pulley 5 and collides with the case 7. The case 7 is formed with a reinforcing portion 15 at a portion where the collision of the broken chain belt 6 is predicted. The reinforcement part 15 is comprised so that the intensity | strength of the case 7 may be raised with a stiffening rib, for example. Alternatively, the strength of the case 7 is increased by partially increasing the thickness of the case 7.

  When the chain belt 6 is broken during the operation of the CVT 1, the guide rail 8 is fixed in a state where a predetermined posture is maintained as described above. Therefore, the broken chain belt 6 is predicted to collide with a predetermined portion of the inner wall surface 7 a of the case 7 after traveling along the guide rail 8. In this case, as shown in FIG. 1, the guide rail 8 and the guide stopper 13 are engaged to stop the rotation of the guide rail 8 in the longitudinal direction of the guide portion 8a from the guide portion 8a. It can be predicted as an intersection P1 between the extended line L1 extending to the inner wall 7a of the case 7. Based on this, the reinforcing portion 15 is formed in a predetermined range including the intersection point P <b> 1 in the case 7. That is, the reinforcing portion 15 is formed only in a portion where it is predicted that the broken chain belt 6 will collide and the case 7 is insufficient in strength against the impact load at the time of the collision. Therefore, it is possible to suppress an increase in weight and cost due to reinforcement, as compared with a case where the case 7 is entirely reinforced assuming that the chain belt 6 is broken.

  1 and 2 show an example in which a spring member is provided only on one guide rail 8, the CVT 1 is a spring member such as a torsion coil spring 12 only on the other guide rail 9. May be provided. Further, as shown in FIG. 3, spring members can be provided on both the guide rail 8 and the guide rail 9.

  In the example shown in FIG. 3, the torsion coil spring 12 is provided on the guide rail 8 as in the example shown in FIGS. In the example shown in FIG. 3, in the torsion coil spring 12, one arm portion 12 b is attached to the guide rail 8 and the other arm portion 12 c is formed in the case 7 in a state where a load is applied in the direction in which the spring is wound. The stopper 21 is attached. The coil portion 12a is fitted into the shaft 10 as in the example shown in FIGS. Therefore, the guide rail 8 is given an elastic force by the torsion coil spring 12 to rotate the guide rail 8 in one direction (clockwise in FIG. 3).

  The stopper 21 functions as a spring stopper for locking the arm portion 12c of the torsion coil spring 12 as described above, and stops its rotation when the guide rail 8 is rotated by the elastic force of the torsion coil spring 12. It is also configured to function as a stopper portion. That is, the stopper 21 locks the arm portion 12c of the torsion coil spring 12 as described above, and when the guide rail 8 is rotated by the elastic force of the torsion coil spring 12, a predetermined portion of the guide portion 8a. It is formed integrally with the case 7 at a position where it is locked. Therefore, also in the CVT 1 shown in FIG. 3, when the chain belt 6 is broken, the guide rail 8 is once rotated by the elastic force of the torsion coil spring 12 and then stopped by the stopper 21. FIG. As shown, it is fixed while maintaining a predetermined posture.

  On the other hand, in the example shown in FIG. 3, in addition to the torsion coil spring 12 being provided on the guide rail 8 as described above, the torsion coil spring 22 is provided on the guide rail 9. The torsion coil spring 22 uses the above-described shaft 11 that rotatably supports the guide rail 9 as a guide rod, and a coil portion 22 a is fitted on the shaft 11. The torsion coil spring 22 is attached to the guide rail 9 with one arm portion 22b attached to the stopper 23 formed on the case 7 with a load applied in the direction of winding the spring. It has been. In this case, the guide rail 9 is given an elastic force by the torsion coil spring 22 to rotate the guide rail 9 in one direction (counterclockwise direction in FIG. 3).

  The stopper 23 functions as a spring stopper for locking the arm portion 22c of the torsion coil spring 22 as in the case of the stopper 21 described above, and when the guide rail 9 is rotated by the elastic force of the torsion coil spring 22, It is also configured to function as a stopper portion that stops the rotation. In other words, the stopper 23 locks the arm portion 22c of the torsion coil spring 22 as described above, and when the guide rail 9 is rotated by the elastic force of the torsion coil spring 22, a predetermined portion of the guide portion 9a. It is formed integrally with the case 7 at a position where it is locked. Therefore, when the chain belt 6 is broken, the guide rail 9 is temporarily rotated by the elastic force of the torsion coil spring 22 and then stopped by the stopper 23, and maintains a predetermined posture as shown in FIG. It is fixed in the state.

  Also in the CVT 1 shown in FIG. 3, it is predicted that the broken chain belt 6 is released from the primary pulley 3 or the secondary pulley 5 and collides with the case 7. The case 7 is formed with a reinforcing portion 15 and a reinforcing portion 24 at a portion where a collision of the broken chain belt 6 is predicted. The reinforcing portion 15 has the same configuration as the reinforcing portion 15 shown in FIGS. 1 and 2 described above, and the broken chain belt 6 is fixed in posture as shown in FIG. 3 and travels along the guide rail 8. Later, it is formed at a place where it is predicted to collide with the case 7. The reinforcing portion 24 is formed at a location where the broken chain belt 6 is predicted to collide with the case 7 after the posture is fixed as shown in FIG. Similar to the reinforcing portion 15, the reinforcing portion 24 is configured to increase the strength of the case 7 by, for example, a stiffening rib. Alternatively, the strength of the case 7 is increased by partially increasing the thickness of the case 7.

  The location where the broken chain belt 6 is predicted to collide with the inner wall surface 7a of the case 7 after traveling along the guide rail 9 can be obtained in the same manner as in the case of the reinforcing portion 15 described above. That is, as shown in FIG. 3, in the state where the guide rail 9 and the stopper 23 are engaged and the rotation of the guide rail 9 is stopped, the extension line L2 extending from the guide portion 9a to the longitudinal direction of the guide portion 9a, It can be predicted as the intersection P2 with the inner wall surface 7a of the case 7. Based on this, the reinforcing part 24 is formed in a predetermined range including the intersection point P <b> 2 in the case 7.

  Therefore, also in the CVT 1 shown in FIG. 3, the reinforcing portion 15 and the reinforcing portion 24 are predicted to collide with the broken chain belt 6, and there is a concern that the strength of the case 7 is insufficient with respect to the impact load at the time of the collision. Only formed. Therefore, it is possible to suppress an increase in weight and cost due to reinforcement, as compared with a case where the case 7 is entirely reinforced assuming that the chain belt 6 is broken.

  In the example shown in FIG. 3, both the guide rail 8 and the guide ale 9 are provided with spring members and are provided with a function of guiding the traveling direction of the broken chain belt 6. Usually, the chain belt 6 is likely to break at either the string portion 6a or the string portion 6b. Therefore, it is considered that the broken chain belt 6 collides with the case 7 after traveling along either the guide rail 8 or the guide rail 9. That is, it is predicted that the broken chain belt 6 collides with a portion of the predetermined range including the intersection P1 and the predetermined range including the intersection P2 of the case 7. Therefore, in the example shown in FIG. 3, by providing the reinforcing portion 15 and the reinforcing portion 24 as described above, damage to the case 7 due to the collision of the broken chain belt 6 can be effectively and reliably ensured. Can be suppressed.

  DESCRIPTION OF SYMBOLS 1 ... Belt type continuously variable transmission (CVT), 2 ... Input shaft, 3 ... Primary pulley, 3a ... Pulley groove, 4 ... Output shaft, 5 ... Secondary pulley, 5a ... Pulley groove, 6 ... Chain belt, 6a, 6b ... string part, 7 ... case, 7a ... inner wall surface, 8,9 ... guide rail, 8a, 9a ... guide part, 8b, 9b ... support part, 10,11 ... shaft, 12,22 ... torsion coil spring (spring member) , 13 ... Guide stopper (stopper part), 14 ... Spring stopper, 15, 24 ... Reinforcement part, 21 and 23 ... Stopper (stopper part), L1, L2 ... Extension line, P1, P2 ... Intersection point.

Claims (1)

A primary pulley, a secondary pulley, a chain belt that is wound around each pulley groove of the primary pulley and the secondary pulley and transmits power between the primary pulley and the secondary pulley, the primary pulley, and the secondary pulley A guide rail that suppresses vibration of the chain belt by contacting the linearly proceeding string portion with the pulley, and the primary pulley, the secondary pulley, the chain belt, and the guide rail are stored. A belt-type continuously variable transmission that changes a gear ratio by changing a groove width of the pulley groove.
The guide rail includes a guide portion that extends in a length direction of the string portion and on which the chain belt slides, and a support portion that rotatably supports the guide portion, and the string according to the change in the gear ratio. Is supported by the case so as to rotate following the change in the inclination of the traveling direction of the part,
At least one guide rail is provided with a spring member that applies an elastic force to rotate the guide rail in one rotation direction,
The case is formed with a stopper portion that engages with the guide rail and stops the rotation of the guide rail when the guide rail is rotated by the elastic force.
In the state where the guide rail and the stopper portion are engaged and the rotation of the guide rail is stopped, an intersection of an extension line extending from the guide portion in the longitudinal direction of the guide portion and the inner wall surface of the case is included. A belt-type continuously variable transmission, wherein a reinforcing portion is formed in a predetermined range of the case so that strength of a portion in the predetermined range is higher than other portions not including the predetermined range.

Images