JP6360207B2 - Pulley structure of belt type continuously variable transmission - Google Patents

Description

  The present invention relates to a drive pulley in which a movable pulley half can be opened and closed in an axial direction with respect to a fixed pulley half, and a driven pulley in which a movable pulley half can be opened and closed in an axial direction with respect to a fixed pulley half. And a metal belt wound around the drive pulley and the driven pulley, and changing the groove width of the drive pulley and the driven pulley hydraulically to change the gear ratio between LOW and OD. The present invention relates to a pulley structure of a step transmission.

  A stopper that restricts the limit position in the opening direction of the movable pulley half (movable sheave) of the drive pulley (primary pulley) of the belt-type continuously variable transmission is provided, and the movable pulley half is pressed against the stopper to make the groove width of the pulley It is known from Patent Document 1 below that the accuracy of the LOW speed ratio is ensured by fixing to a predetermined value.

  Further, when the movable pulley half (movable sheave) of the drive pulley (primary pulley) of the belt-type continuously variable transmission opens further than the position where the maximum gear ratio is reached (the limit position in the opening direction), the movable pulley half By compressing the elastic member provided on the outer periphery of the input shaft at the inner cylinder of the body, even if the hydraulic system of the drive pulley fails, the elastic force of the compressed elastic member Patent Document 2 listed below is known to prevent slipping and enable the vehicle to travel.

Japanese Patent No. 5178602 JP2015-190539A

  FIG. 9 is a schematic view of a belt type continuously variable transmission in which an endless metal belt 03 is wound around a drive pulley 01 and a driven pulley 02 as viewed in the axial direction. A string on the tight side toward the inlet of the driven pulley 02 and a string on the loose side from the outlet of the driven pulley 02 toward the inlet of the drive pulley 01 are provided. In the string on the tight side, the metal elements 05 supported by the metal ring 04 are in close contact with each other, and the driving force is transmitted from the drive pulley 01 to the driven pulley 02 by the pressing force between the metal elements 05. On the other hand, in the string on the loose side, a gap is generated between the metal elements 05, so that the driving force is not transmitted.

  In the idle arc region on the inlet side of the drive pulley 01 that is continuous to the downstream side of the slack side string, a gap remains between the metal elements 05..., But the active arc that is located downstream and continues to the string on the tight side. In the region, the metal elements 05 are in close contact with each other. In the driven pulley 02, the entire area from the inlet to the outlet is an active arc area, and the metal elements 05 are in close contact with each other. 9, the gap between the metal elements 05 is exaggerated in the string on the loose side and the idle arc region.

  By the way, as described in the above-mentioned Patent Document 1, when the opening limit position of the movable pulley half of the drive pulley is restricted by the opening stopper to ensure the accuracy of the LOW speed ratio, the following problem occurs. To do. That is, when the movable pulley half of the drive pulley opens and contacts the stopper at the LOW gear ratio, the pulley is driven by hydraulic pressure (force that pinches the metal belt between the fixed pulley half and the movable pulley half). Since the reaction force due to the contact between the pulley half and the opening stopper is superimposed, it is necessary to change the hydraulic pressure for urging the movable pulley half in order to cancel the reaction force.

  At this time, as described above, since the active arc region and the idle arc region exist in the drive pulley, the change of the hydraulic pressure that urges the movable pulley half causes the fixed pulley half and the movable pulley half to move. The pulley V surface is elastically deformed to change the sizes of the active arc region and the idle arc region, thereby increasing the frictional force of the pulley V surface to prevent the metal belt from slipping or between the pulley V surface and the metal belt. The surface pressure can be maintained at an appropriate value to prevent abnormal wear. However, since the above control is affected by the rigidity of the pulley, it is difficult to secure an active arc region of an appropriate size according to the transmission torque at that time, before and after the movable pulley half contacts the opening stopper. The slip amount of the metal belt changes, and problems such as a decrease in friction coefficient, a decrease in transmission efficiency, and an increase in wear amount of pulleys and metal elements occur.

  Conversely, when the closed limit position of the movable pulley half of the driven pulley is regulated by a closing stopper to ensure the accuracy of the LOW gear ratio, the driven pulley has no idle arc and is all active arc. The above problem does not occur. However, when the movable pulley half of the driven pulley that is urged and moved by hydraulic pressure at the time of changing the gear ratio collides with the stopper at the closing limit position and stops, a surge pressure is generated in the oil chamber of the pulley due to the impact. As a result, the durability of the pulley may be adversely affected. In order to prevent this, if the strength of the driven pulley is increased so as to withstand the surge pressure, there is a problem that the size and weight of the driven pulley increase.

  The present invention has been made in view of the above-described circumstances, and prevents the generation of surge pressure when the movable pulley half of the driven pulley of the belt type continuously variable transmission reaches the closing limit position with a simple structure. With the goal.

  In order to achieve the above object, according to the first aspect of the present invention, there is provided a drive pulley in which the movable pulley half can be opened and closed in the axial direction with respect to the fixed pulley half, and the fixed pulley half. On the other hand, the movable pulley half includes a driven pulley whose axial direction can be opened and closed, and the drive pulley and a metal belt wound around the driven pulley, and the groove width of the drive pulley and the driven pulley is changed by hydraulic pressure. This is a pulley structure of a belt-type continuously variable transmission that changes the gear ratio between LOW and OD by being pressed by the movable pulley half of the drive pulley that moves in the opening direction in the vicinity of the LOW gear ratio. An elastic member that is elastically deformed, and a closing stopper that restricts a moving end of the movable pulley half of the driven pulley in the closing direction at a LOW speed ratio. Pulley structure of a belt-type continuously variable transmission is proposed to the symptoms.

  According to a second aspect of the invention, in addition to the configuration of the first aspect, the elastic deformation amount of the elastic member is maximized at a LOW speed ratio, and the pulley of the belt type continuously variable transmission is characterized in that A structure is proposed.

  The disc spring 28 of the embodiment corresponds to the elastic member of the present invention.

  According to the first aspect of the present invention, since the closing stopper for restricting the moving end of the movable pulley half of the driven pulley in the closing direction at the LOW speed ratio is provided, the closed position of the driven pulley is accurately regulated by the closing stopper. By eliminating the need to provide an opening stopper on the drive pulley side where idle arcs and active arcs are present, and avoiding changes in the rigidity of the drive pulley due to the provision of the opening stopper, the slip amount of the metal belt in the drive pulley can be increased. In addition, it is possible to prevent a reduction in power transmission efficiency due to the metal belt and an increase in wear amount of the pulley and the metal belt.

  In addition, since an elastic member that is elastically deformed by being pressed by the movable pulley half of the drive pulley that moves in the opening direction in the vicinity of the LOW speed ratio, the movable pulley half of the driven pulley that moves toward the closed position is closed. Before colliding with the stopper, the movable pulley half of the drive pulley moving toward the open position comes into contact with the elastic member and decelerates. As a result, the deceleration of the movable pulley half of the drive pulley is transmitted to the movable pulley half of the driven pulley via the metal belt, and the moving speed of the movable pulley half of the driven pulley that moves toward the closed position is determined. Generation of surge pressure can be prevented by decelerating and slowly contacting the closing stopper.

  According to the second aspect of the present invention, since the elastic deformation amount of the elastic member becomes maximum at the LOW speed ratio, the hydraulic system on the drive pulley side fails at the LOW speed ratio, and the clamping pressure of the metal belt due to the hydraulic pressure is generated. Even if it cannot be performed, the minimum necessary clamping pressure can be generated by the elastic force of the elastically deformed elastic member, and the vehicle can be retreated to the repair shop.

The figure which shows the structure of a belt-type continuously variable transmission. FIG. 2 is a detailed view of a drive pulley in FIG. 1. FIG. 2 is a detailed view of the driven pulley in FIG. 1. The graph which shows the relationship of the friction coefficient between a pulley and a metal belt with respect to input torque. The graph which shows the relationship of the transmission efficiency of the driving force with respect to input torque. The graph which shows the abrasion depth of the pulley after the durability test in a LOW gear ratio. The graph which shows the relationship of the slip ratio of a metal belt with respect to input torque. Explanatory drawing of an effect | action of embodiment and a comparative example. Explanatory drawing of the active arc area | region and idle arc area | region of a pulley.

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

  As shown in FIG. 1, a belt-type continuously variable transmission that continuously transmits a rotation of an input shaft 11 connected to an engine to an output shaft 12 connected to driving wheels is provided on the input shaft 11. The metal belt 15 is wound around the drive pulley 13 and the driven pulley 14 provided on the output shaft 12. In FIG. 1, the upper side of the axis of the input shaft 11 and the output shaft 12 shows the OD (overdrive) state where the speed ratio is minimum, and the lower side of the axis of the input shaft 11 and the output shaft 12 has the maximum speed ratio. The LOW state is shown.

  The drive pulley 13 includes a fixed-side pulley half 16 fixed to the input shaft 11 and a movable-side pulley half 17 supported on the input shaft 11 via a sliding key 18 so as to be axially slidable and relatively non-rotatable. The movable pulley half 17 can be moved toward and away from the fixed pulley half 16. A piston 19 fixed to the input shaft 11 is slidably fitted to a cylinder 20 formed integrally with the movable pulley half 17, and between the piston 19, the cylinder 20 and the movable pulley half 17. An oil chamber 21 is defined.

  The driven pulley 14 includes a fixed-side pulley half 22 fixed to the output shaft 12 and a movable-side pulley half 23 supported on the output shaft 12 via a sliding key 24 so as to be slidable in the axial direction and not relatively rotatable. The movable pulley half 23 can be moved toward and away from the fixed pulley half 22. A piston 25 fixed to the output shaft 12 is slidably fitted to a cylinder 26 formed integrally with the movable pulley half 23, and between the piston 25, the cylinder 26 and the movable pulley half 23. An oil chamber 27 is defined.

  Accordingly, when the hydraulic pressure applied to the oil chamber 21 of the drive pulley 13 is decreased and the hydraulic pressure applied to the oil chamber 27 of the driven pulley 14 is increased, the movable pulley half 17 of the drive pulley 13 is separated from the fixed pulley half 16. Thus, the groove width increases, the movable pulley half 23 of the driven pulley 14 approaches the fixed pulley half 22, the groove width decreases, and the winding diameter of the metal belt 15 around the drive pulley 13 decreases. As the winding diameter of the metal belt 15 around the driven pulley 14 increases, the gear ratio increases toward LOW.

  Conversely, when the hydraulic pressure applied to the oil chamber 21 of the drive pulley 13 is increased and the hydraulic pressure applied to the oil chamber 27 of the driven pulley 14 is decreased, the movable pulley half 17 of the drive pulley 13 becomes the fixed pulley half 16. The groove width is reduced by approaching, and the stationary pulley half 22 is separated from the movable pulley half 23 of the driven pulley 14 to increase the groove width, and the winding diameter of the metal belt 15 around the drive pulley 13 is increased. As the wrapping diameter of the metal belt 15 around the driven pulley 14 decreases, the transmission ratio decreases toward OD.

  As shown in FIG. 2, a disc spring 28 is sandwiched between the step portion 11a of the input shaft 11 and the inner peripheral portion of the piston 19, and a movable pulley that fits slidably on the outer periphery of the input shaft 11. The end of the cylindrical portion 17a of the half body 17 is opposed to the disc spring 28 so as to be able to come into contact therewith. When the gear ratio changes from the OD side toward the LOW side, the movable pulley half 17 of the drive pulley 13 moves away from the fixed pulley half 16, and the movable pulley is immediately before the position of the LOW gear ratio. The end portion of the cylindrical portion 17a of the half body 17 abuts on the disc spring 28 to be elastically deformed, and the disc spring 28 is completely compressed at the position of the LOW speed ratio.

As shown in FIG. 3, a step portion 12 a is formed on the outer periphery of the output shaft 12, and the inner periphery of the movable pulley half 23 of the driven pulley 14 can contact the step portion 12 a of the output shaft 12. A step portion 23 a is formed, and both step portions 12 a and 23 a cooperate to constitute a closing stopper 29 that regulates the closed position of the driven pulley 14.

  Next, the operation of the embodiment of the present invention having the above configuration will be described.

  In FIG. 1, when the hydraulic pressure applied to the oil chamber 21 of the drive pulley 13 is decreased to increase the hydraulic pressure applied to the oil chamber 27 of the driven pulley 14, the movable pulley half 17 of the drive pulley 13 is fixed to the fixed pulley half 16. The width of the driven pulley 14 increases toward the fixed pulley half 22 and the groove width decreases as the groove width increases, and the gear ratio changes to the LOW side. A closing stopper 29 composed of the step portion 12a of the shaft 12 and the step portion 23a of the movable pulley half 23 of the driven pulley 14 is brought into contact with each other, and the gear ratio is fixed to LOW.

  As described above, the present embodiment establishes the LOW gear ratio with the closing stopper 29 provided on the driven pulley 14 side. However, as a comparative example, on the contrary, the opening stopper provided on the drive pulley 13 side uses the movable pulley. Consider a case where the movement of the half body 17 to the opening side is restricted to establish a LOW speed ratio.

  In this comparative example, when the gear ratio reaches LOW and the movable pulley half 17 of the drive pulley 13 is pressed against the opening stopper by the hydraulic pulley thrust, the hydraulic pulley thrust is applied to the movable pulley half 17 and the opening stopper. Since it is urged by the reaction force caused by the contact, it is necessary to reduce the pulley thrust by the hydraulic pressure in order to prevent the metal belt 15 and the pulley V surface from being worn. As shown in FIG. 9, the drive pulley 13 has an active arc region and an idle arc region, and the fixed pulley half 16 and the movable pulley half 17 of the drive pulley 13 are reduced by a decrease in pulley thrust due to hydraulic pressure. By locally elastically deforming, the active arc region is reduced and the idle arc region is enlarged, thereby reducing the frictional force on the pulley V surface and preventing the occurrence of abnormal wear.

  However, since the amount of change in the active arc region and the idle arc region is affected by the rigidity of the pulley, it is difficult to secure an active arc region of an appropriate size according to the transmission torque at that time. There is a concern that the slip amount of the metal belt 15 changes before and after the opening 17 comes into contact with the stopper, causing problems such as a decrease in friction coefficient, a decrease in transmission efficiency, and an increase in the wear amount of pulleys and metal elements.

  On the other hand, in the present embodiment in which the closed stopper 29 for the movable pulley half 23 is provided on the driven pulley 14 side, the movable pulley half 23 contacts the close stopper 29 in the process of changing the gear ratio toward LOW. A reaction force load that prevents the increase in the pulley thrust force is generated, and even if the hydraulic pressure applied to the oil chamber 27 of the driven pulley 14 is increased to cancel the reaction force load, the driven pulley 14 only has an active arc region in the first place. Therefore, the ratio between the active arc region and the idle arc region does not change. As a result, it is possible to avoid a sudden change in the slip amount of the metal belt 15 before and after the movable pulley half 23 comes into contact with the closing stopper 29, thereby reducing the friction coefficient, the transmission efficiency, and the wear amount of the pulley and the metal element. Generation of increase etc. is reduced.

  FIG. 4 is a graph showing the relationship of the friction coefficient between the metal belt 15 and the pulley with respect to the input torque at the LOW speed ratio of the belt-type continuously variable transmission. From this graph, a closing stopper 29 is provided on the driven pulley 14 side. It can be seen that the friction coefficient of the embodiment (see ◇) exceeds the comparative example (see □) in which an opening stopper is provided on the drive pulley 13 side.

  FIG. 5 is a graph showing the relationship of the driving force transmission efficiency with respect to the input torque at the LOW speed ratio of the belt-type continuously variable transmission. From this graph, an embodiment in which a closing stopper 29 is provided on the driven pulley 14 side ( It can be seen that the transmission efficiency of (see ◇) exceeds the comparative example (see □) in which an opening stopper is provided on the drive pulley 13 side.

  FIG. 6 is a graph showing the wear depth of the drive pulley 13 generated by the endurance test performed at the LOW speed ratio. From this graph, the wear amount of the embodiment is significantly reduced compared to the wear amount of the comparative example. You can see that

  FIG. 7 is a graph showing the relationship between the slip rate of the metal belt 15 and the input torque. From this graph, the belt slip rate in the embodiment (see ◇) in which the closed stopper 29 is provided on the driven pulley 14 side is the drive slip rate. It can be seen that the belt slip ratio of the comparative example (see □) in which the opening stopper is provided on the pulley 13 side is lower.

  According to the present embodiment, the movable pulley half 17 of the drive pulley 13 moves in the opening direction and the movable pulley half 23 of the driven pulley 14 moves in the closing direction in the process of changing the gear ratio to the LOW side. When moving, just before the movable pulley half 23 of the driven pulley 14 comes into contact with the stopper 29 and stops, the cylindrical portion 17a of the movable pulley half 17 of the drive pulley 13 that moves in the opening direction moves the disc spring. Abutting on 28, the disc spring 28 is elastically deformed. When the disc spring 28 is completely elastically deformed, the movable pulley half 23 of the driven pulley 14 comes into contact with the stopper 29 and stops.

Thus, immediately before the gear ratio reaches LOW, the moving speed of the movable pulley half 17 of the drive pulley 13 is reduced by the elastic deformation of the disc spring 28, so that the metal belt 15 is attached to the drive pulley 13. The moving speed in the closing direction of the movable pulley half 23 of the driven pulley 14 connected thereto is also reduced, and the movable pulley half 23 of the driven pulley 14 is prevented from colliding with the closing stopper 29 vigorously. As a result, the oil pressure in the oil chamber 27 that urges the movable pulley half 23 of the driven pulley 14 is prevented from suddenly increasing, and the surging phenomenon is prevented from occurring. Therefore, the driven pulley 14 has high strength to withstand surge pressure. And the driven pulley 14 can be reduced in size and weight while ensuring durability, and the braking force that decelerates the movement of the movable pulley half 17 of the drive pulley 13 in the opening direction is a metal belt. 15 is transmitted to the movable pulley half 23 of the driven pulley 14 via the metal belt 15, the metal belt 15 formed by stacking a large number of metal elements on the metal ring has a frictional force between the metal elements and the metal element and the metal ring. The movable pulley half 23 of the driven pulley 14 closes and stops in order to exert a damping effect by the frictional force between them. The speed of collision with the pad 29 is further effectively reduced.

  Further, when the hydraulic system on the drive pulley 13 side fails at the LOW gear ratio and the hydraulic pressure cannot be supplied to the oil chamber 21, the metal belt 15 is interposed between the fixed pulley half 16 and the movable pulley half 17 of the drive pulley 13. Therefore, there is a problem that the metal belt 15 slips and the vehicle cannot travel. However, according to the present embodiment, even if the hydraulic system on the drive pulley 13 side fails in the LOW speed ratio, the movable pulley half of the drive pulley 13 is compressed by the elastic force of the disc spring 28 that is compressed and elastically deformed. By urging the body 17 toward the stationary pulley half 16, the metal belt 15 is clamped and the vehicle can be retreated to a repair shop.

FIG. 8 explains the operational effects of the present embodiment in comparison with the operational effects of the comparative example. In the present embodiment, the load rises when the movable pulley half 23 of the drive pulley 13 compresses the disc spring 29 immediately before the LOW speed ratio, but the movable pulley half of the driven pulley 14 is brought about by the effect of the disc spring 29. Since the body 23 is prevented from colliding with the closing stopper 29 vigorously, load fluctuation in the LOW speed ratio does not occur.
In Comparative Example 1 in which the closed position of the movable pulley half of the driven pulley is regulated by a closing stopper, load fluctuation (surge pressure) occurs because the movable pulley half collides with the closing stopper vigorously at the LOW speed ratio. To do.

  In Comparative Example 2 where the opening position of the movable pulley half of the drive pulley is regulated by an opening stopper, load fluctuation (surge pressure) occurs because the movable pulley half collides with the opening stopper vigorously at the LOW gear ratio. To do.

  In Comparative Example 3 (see Japanese Patent Application Laid-Open No. 2015-190539) in which the elastic member is compressed by the movable pulley half when the movable pulley half of the drive pulley passes the position of the LOW speed ratio. When the movable pulley half passes through the position of the LOW gear ratio and compresses the elastic member, the load increases. When the movable pulley half of the drive pulley finally hits the open limit position, load fluctuation (surge pressure) is generated. Occur.

  The embodiments of the present invention have been described above, but various design changes can be made without departing from the scope of the present invention.

  For example, the elastic member of the present invention is not limited to the disc spring 28 of the embodiment.

13 Drive pulley 14 Driven pulley 15 Metal belt 16 Drive pulley stationary pulley half 17 Drive pulley movable pulley half 22 Driven pulley fixed pulley half 23 Driven pulley movable side pulley half 28 Disc spring (elasticity Element)
29 Closing stopper

Claims (2)

A drive pulley (13) in which the movable pulley half (17) can be opened and closed in the axial direction with respect to the fixed pulley half (16), and a movable pulley half (with respect to the fixed pulley half (22)). 23) comprises a driven pulley (14) that can be opened and closed in the axial direction, the drive pulley (13), and a metal belt (15) wound around the driven pulley (14), and the drive pulley (13) and A pulley structure of a belt-type continuously variable transmission that changes a gear ratio between LOW and OD by changing the groove width of the driven pulley (14) with hydraulic pressure,
An elastic member (28) that is elastically deformed by being pressed by the movable pulley half (17) of the drive pulley (13) that moves in the opening direction in the vicinity of the LOW speed ratio, and the driven pulley (14) at the LOW speed ratio. A pulley structure for a belt-type continuously variable transmission, comprising: a closing stopper (29) for restricting a moving end in the closing direction of the movable pulley half (23). The pulley structure of the belt-type continuously variable transmission according to claim 1, wherein the elastic deformation amount of the elastic member (28) is maximized at a LOW speed ratio.

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