JP2008185047A - Belt type continuously variable transmission - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To increase the range of gear ratios by changing the width of a belt by elastic deformation. <P>SOLUTION: This belt type continuously variable transmission is structured such that a belt 16 formed by binding multiple plate-like elements 18 annularly arranged in a stacked state by a ring 17 is wound around a drive pulley 2 and a driven pulley 3 allowing widths of grooves A1 and A2 to be changed; the elements 18 transmit torque by frictional force by being sandwiched between the pulleys 2 and 3 in the grooves A1 and A2; and a change gear ratio according to a winding radius of the belt 16 to the drive pulley 2 and the driven pulley 3 is set. In the belt type continuously variable transmission, on a part of the element 18 adjacent to the center relative to both its ends contacting the pulleys 2 and 3, an elastic deformation part E easily elastically deformable at least in the width direction of the element 18 relative to both the ends is arranged. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a belt-type continuously variable transmission having a structure in which a belt formed by arranging a large number of elements in an annular shape and bundling them with a ring is wound around a drive pulley and a driven pulley. .

  Generally, a belt-type continuously variable transmission is a transmission that uses a pressing belt and two sets of pulleys, a driving pulley and a driven pulley, to change the transmission ratio steplessly. The thing of patent document 1 is known as an example of the press belt used for a machine. The pressing belt incorporated in the belt-type continuously variable transmission described in Patent Document 1 has a large number of plate pieces, called elements, arranged in an annular shape by overlapping each other in the plate thickness direction. Are endlessly bound by a band-like body called a ring (or also called a “hoop”). Further, this element is formed so that the thickness of the central portion thereof is slightly thinner than the thickness of both side portions.

  Such a pressure belt is wound around a pair of pulleys on the drive side and the driven side, the drive pulley is driven, and the pinching pressure due to the hydraulic pressure from the hydraulic cylinder that controls the groove width of the pulley is narrowed by the driven pulley. Act on the element. Thereby, the frictional force of the contact portion with the drive pulley and the compressive force in the element stacking direction, that is, the thickness direction of the element applied from the drive pulley to the element according to the torque of the drive pulley act on the element. . Then, the compressive force transmitted to the element in contact with the drive pulley is transmitted to the element in contact with the driven pulley via each linear element that is not wound around the pulley. When a compressive force is transmitted to the element in contact with the driven pulley, a frictional force at a contact portion between the element and the driven pulley, and a torque for rotating the driven pulley in accordance with the transmitted compressive force are generated. appear. In this way, power is transmitted between the driving pulley and the driven pulley via the pressing belt.

Japanese Utility Model Publication No. 63-91745

  Shifting in the belt-type continuously variable transmission is performed by changing the belt winding radius with respect to each pulley. Specifically, each pulley is constituted by a fixed sheave and a movable sheave that approaches and separates from the fixed sheave, and the belt winding radius is changed by changing the interval between these sheaves, that is, the groove width. It is executed by changing. The moving range of the movable sheave is predetermined in terms of the mechanism. For example, the movable sheave in the drive pulley is moved within a certain range in the axial direction. This movement of the movable sheave changes the belt wrapping radius to a larger or smaller value, but even if the groove width is minimized, the belt does not come off the pulley, and even if the groove width is maximized, the belt cannot be removed. It is comprised so that it may not interfere with this member. In other words, even with the maximum gear ratio and the minimum gear ratio set according to the movable range of the movable sheave, regions where torque can be transmitted by contacting the belt remain on the inner and outer peripheral sides of the pulley. ing. In other words, in the related art, the torque transmission surface of each pulley is limited and used. For this reason, a large speed ratio width, which is the difference or ratio between the maximum speed ratio and the minimum speed ratio, can be increased. There was a possibility that the transmission ratio range could be restricted.

  Further, the rigidity of the pulley is smaller toward the outer peripheral side. Therefore, when the belt clamping pressure is increased to increase the transmission torque capacity, the outer peripheral side of the pulley may bend in the direction of increasing the groove width. When such deformation occurs, a state occurs in which the pulley sandwiches the lower part of the element constituting the belt (the inner peripheral part when viewed from the entire belt). This is sometimes referred to as “bottom hit”, and when such a state occurs, there is a possibility that the transmission efficiency of power is reduced.

  The present invention has been made paying attention to the above technical problem, and is a belt-type continuously variable element capable of elastically deforming the element in the width direction to increase the speed ratio width and prevent so-called bottom contact. The object is to provide a transmission.

  In order to achieve the above object, the invention according to claim 1 is a drive in which a belt in which a large number of plate-like elements arranged in an annular form in a stacked state are bound together by a ring can change the width of the groove. It is wound around a pulley and a driven pulley, the torque is transmitted by a frictional force caused by the element being pinched by the pulley in the groove, and the belt is driven by the belt with respect to the driving pulley and the driven pulley. In a belt-type continuously variable transmission for setting a transmission gear ratio, an elastically deformable portion that is more easily elastically deformed than at both ends in the width direction of the element at a portion closer to the center than both ends contacting the pulley of the element Is provided.

  According to a second aspect of the present invention, in the first aspect of the invention, the elastically deformable portion is formed of a material having a smaller elastic coefficient than the material forming the both end portions. It is a transmission.

  A third aspect of the invention is the belt-type continuously variable transmission according to the first or second aspect, wherein the elastically deforming portion is provided at a central portion in the width direction of the element.

  According to a fourth aspect of the present invention, in the invention according to any one of the first to third aspects, the elastic deformation portion is wide on the rotation center side of the driving pulley or the driven pulley while being sandwiched in the groove. The belt-type continuously variable transmission is characterized in that it is formed in a tapered shape whose width is gradually narrowed on the opposite side.

  According to a fifth aspect of the present invention, in the invention according to any one of the first to fourth aspects, the elastically deformable portion is provided at a position deviating in a width direction with respect to the ring wound around the element. This is a belt type continuously variable transmission.

  According to the first or second aspect of the present invention, when the clamping force by the pulley against the element increases while tension is applied to the belt, the elastically deforming portion is elastically deformed in the width direction and the width dimension of the element is reduced. On the contrary, when the clamping pressure is relatively lowered, the elastic deformation portion is enlarged in the width direction by the elastic force. Therefore, on the pulley side where the winding radius is small, the number of elements fitted in the groove of the pulley is small, so that the clamping force acting on one element becomes relatively large, so that the bottom side of the groove, that is, the pulley The belt winding position moves to the rotation center side of the belt. On the other hand, on the pulley side with a large winding radius, since the number of elements fitted in the groove of the pulley is large, the clamping force acting on one element becomes relatively small. When the width dimension of the element is increased by the elastic restoring force of the deforming portion, the belt winding position moves outward in the groove opening side, that is, in the radial direction of the pulley. As a result, the belt winding radius difference or ratio between the driving pulley and the driven pulley is increased by the amount of deformation of the elastically deforming portion, and as a result, the settable gear ratio range is increased.

  According to the invention of claim 3, in addition to the effect similar to the effect of the invention of claim 1 or 2, the left and right displacement amounts or the positions after the displacement in the width direction of the element can be made symmetric. .

  According to the invention of claim 4, the elastic deformation in the width direction of the entire element is large on the inside in the radial direction of the pulley and relatively small on the outside according to the shape of the elastic deformation portion. Therefore, the change in the shape of both ends of the element follows the change in the shape of the torque transmission surface (flank surface) of the pulley, and as a result, the uneven contact between the element and the pulley, such as so-called bottom contact, is prevented or Can be suppressed.

  According to the fifth aspect of the present invention, the load that binds the elements to the ring, that is, the load that presses the elements toward the center in the radial direction does not positively act on the elastically deforming portion. Therefore, it can avoid that an elastic deformation part deform | transforms complicatedly, and a contact with an element and a pulley can be maintained in a favorable state.

  The best mode for carrying out the present invention will be described below with reference to the drawings. The belt type continuously variable transmission (hereinafter referred to as “continuously variable transmission”) of the embodiment shown in FIGS. 1 and 2 is, for example, from a driving force source (not shown) of a vehicle to wheels (not shown). It is arranged in the power transmission path. The continuously variable transmission 1 has a primary pulley 2 that is a driving pulley and a secondary pulley 3 that is a driven pulley. The primary pulley 2 is held rotatably about the center Q2. The primary pulley 2 includes a fixed sheave 5 that rotates integrally with the primary shaft 4 and does not move in the axial direction of the primary shaft 4, and a movable sheave 6 that rotates integrally with the primary shaft 4 and is movable in the axial direction of the primary shaft 4. Have. The fixed sheave 5 is formed with an inclined surface (also referred to as a contact surface) 8 as a conical groove forming surface, and the movable sheave 6 is formed with a conical inclined surface (contact surface) 7. A groove A <b> 1 is formed between the inclined surface 7 and the inclined surface 8. And the inclined surfaces 7 and 8 incline in the direction in which the width | variety of groove | channel A1 is narrowed, so that the inner side of the primary pulley 2 in the radial direction is narrowed. Furthermore, an actuator 9 for operating the movable sheave 6 in the axial direction is provided.

  On the other hand, the secondary pulley 3 is held rotatably about the center Q4. The secondary pulley 3 includes a fixed sheave 11 that rotates integrally with the secondary shaft 10 and is fixed in the axial direction of the secondary shaft 10, and a movable sheave 12 that rotates integrally with the secondary shaft 10 and can move in the axial direction of the secondary shaft 10. have. The fixed sheave 11 is formed with an inclined surface (contact surface) 13 as a conical groove forming surface, and the movable sheave 12 is formed with a conical inclined surface (contact surface) 14. A groove A <b> 2 is formed between the inclined surface 13 and the inclined surface 14. And the inclined surfaces 13 and 14 incline in the direction where the width | variety of groove | channel A2 is narrowed, so that the inner side in the radial direction of the secondary pulley 3 is set. Furthermore, an actuator 15 that moves the movable sheave 12 in the axial direction is provided. A pressing belt 16 corresponding to the belt in the present invention is wound around the primary pulley 2 and the secondary pulley 3.

  As shown in FIGS. 3 and 4, the pressing belt 16 includes an annular ring (also referred to as a hoop) 17, and an element (a block or a block) that is a plurality of plate pieces stacked and bound in the circumferential direction of the ring 17. 18). The annular ring 17 is configured by laminating a plurality of thin plates 19 formed of a metal material on the inside and outside. In the present embodiment, two rings 17 are used. All the elements 18 are formed of a metal material, and the elements 18 are connected to each other through a long base portion 20 disposed in the width direction of the grooves A1 and A2 and a neck portion 21 at the center portion of the base portion 20 in the width direction. And a top portion 22.

  At both ends in the width direction of the pressing belt 16, that is, in the width direction of the element 18, a planar shape that can contact the groove forming surfaces (inclined surfaces) 7, 8, 13, 14 of each sheave 5, 6, 11, 12 Contact areas (flank surfaces) 23 and 24 are formed separately. Then, when the pressing belt 16 is wound around the primary pulley 2 and the secondary pulley 3, the contact region 23 is configured in a shape that can contact the inclined surface 7 or the inclined surface 13. Further, the contact region 24 is configured in a shape that can contact the inclined surface 8 or the inclined surface 14. That is, the contact regions 23 and 24 have flank surfaces that are inclined so that the width of the base portion 20 is narrowed toward the inner peripheral side of the pressing belt 16. The angle formed by the contact regions 23 and 24 is substantially the same as the angle formed by the inclined surfaces 7 and 8 and the angle (flank angle) formed by the inclined surfaces 13 and 14.

  On the other hand, two concave portions 29 (see FIG. 3) having a depth in the width direction of the pressing belt 16 are formed between the base portion 20 and the top portion 22 on the left and right. The lower surface in FIG. 4 forming these concave portions 29 is a saddle surface, and the ring 17 is arranged here, and a large number of elements 18 are laminated and bound in an annular shape. A dimple 30 protruding in the stacking direction of the elements 18 is formed on the surface 25 side of the top portion 22 of the element 18. On the opposite side of the element 18 from the dimple 30, a hole 31 having a depth in the stacking direction of the elements 18 is formed. When the elements 18 are bound by the ring 17 and stacked, the dimples 30 are fitted into the holes 31 to restrict relative movement of the adjacent elements 18 in the circumferential direction.

  Each element 18 described above is provided with an elastic deformation portion that facilitates elastic deformation in the width direction. This elastic deformation portion is a portion that is more likely to be elastically deformed at least in the width direction than both ends in the width direction of the element 18, that is, the portion that contacts the pulleys 2 and 3, and the shape is different from the other portions. Alternatively, it is configured to be easily elastically deformed by different materials. For example, as shown in FIGS. 4 and 5, an elastic member E having a relatively small elastic coefficient is provided in a part of the element 18 and is sandwiched between the grooves A1 and A2 of the pulleys 2 and 3. When subjected to pressure, it is configured to elastically deform in the width direction.

  More specifically, the elastic member E having a small elastic coefficient is shown in the figure extending across the base 20, the neck 21, and the top 22 at a substantially central portion in the width direction of the element 18, as shown by hatching in FIG. It is provided along the vertical direction. Therefore, since the elastic member E having a small elastic coefficient in the element 18 has a smaller elastic coefficient than other regions where the elastic member E is not provided, the clamping force received from the primary pulley 2 or the secondary pulley 3 acts in the width direction of the element 18. In this case, the state shown in FIG. 5A is changed to the state shown in FIG. 5B, and as a result, the overall dimension of the element 18 in the width direction is changed from L1 to L2.

  In the embodiment described here, the elastic member E is formed in a rectangular shape when viewed from the front. However, as shown by a broken line in FIG. 4, the elastic member E faces the lower portion (inward) of the element 18. Accordingly, the width F may be increased, that is, the shape F may be formed in a trapezoidal shape (tapered shape), and the region where the elastic member E having a small elastic coefficient is provided is outside the range where the ring 17 exists. In other words, it is preferably provided at a position deviating from the ring 17 in the width direction. If it does in this way, other loads, such as a shear force, may be applied to the elastic member E together with the compressive force in the width direction, and complicated deformation can be prevented from occurring.

  Here, the shift control of the continuously variable transmission 1 will be described. When the position of the primary sheave 2 in the axial direction of the movable sheave 6 is controlled and the width of the groove A1 is adjusted in a state where the belt clamping pressure corresponding to the torque to be transmitted is applied by the secondary pulley 3, the width of the groove A1 is adjusted. The ratio of the winding radius of the pressing belt 16 and the winding radius of the pressing belt 16 in the secondary pulley 3, that is, the gear ratio changes.

  In FIG. 2, the pressing belt 16 contacts the primary pulley 2 to form a winding region B <b> 1, and the pressing belt 16 contacts the secondary pulley 3 to form the winding region B <b> 2. Further, between the winding region B1 and the winding region B2, the region in which the element 18 constituting the pressing belt 16 does not contact either the primary pulley 2 or the secondary pulley 3, that is, the non-wrapping regions B3, B4. Is formed. The contact regions 23 and 24 of the element 18 located in the winding region B1 are in contact with the inclined surfaces 7 and 8. Here, in the winding region B1, on the outlet side B5 in the moving direction of the element 18, the inclined surfaces 7 and 8 depend on the torque of the primary pulley 2 and the frictional force between the element 18 and the inclined surfaces 7 and 8. Thus, the pressing force in the stacking direction is transmitted to the predetermined number of elements 18. Here, as the element 18 moves forward in the moving direction, the pressing force generated between the elements 18 increases. Note that no pressing force is generated between the elements 18 on the upstream side B6 in the moving direction of the element 18 on the upstream side of the outlet side B5.

  Thus, the pressing force transmitted to each element 18 in the thickness direction is transmitted to the element 18 located in the non-wrapping region B3 as shown in FIGS. Next, when each element 18 reaches the winding region B2 in the secondary pulley 3, the contact regions 23, 24 of the element 18 and the inclined surfaces 13, 14 come into contact with each other, and the contact regions 23, 24 of the element 18 and the inclined surface 13 are contacted. , 14, and the pressing force in the stacking direction of the elements 18 is transmitted to the secondary pulley 3 to generate torque that rotates the secondary pulley 3.

  According to the pressing belt 16 of the belt-type continuously variable transmission 1 described above, the elastic member E having a small elastic coefficient is provided in the central portion of the element 18, so that the elastic coefficient is larger than in other areas where the elastic member E is not provided. Is small. For this reason, when the clamping force (clamping pressure) received from the primary pulley 2 or the secondary pulley 3 acts in the width direction of the element 18, the element 18 is uniformly compressed and elastically deformed in the width direction with the central portion as a base point, The dimension in the width direction of the element 18 changes from L1 to L2, as shown in FIG. That is, when the dimension in the width direction changes to L2, the pressing belt 16 moves in a direction in which the winding diameter of the pulleys 2 and 3 decreases by ΔR.

  Such elastic deformation and accompanying dimensional change occur according to the compressive force in the width direction acting on the element 18. Therefore, when the speed ratio is other than “1”, the winding radius of the pressing belt 16 on one of the pulleys 2 and 3 is larger than the winding radius on the other. In the pulleys 2 and 3 having a small winding radius, the number of elements 18 sandwiched between the grooves A1 and A2 is reduced. On the other hand, in the pulleys 3 and 2 having a large winding radius, the element 18 sandwiched in the grooves A2 and A1. The number of will increase. As a result, in the pulleys 2 and 3 having a small winding radius, the compressive load in the width direction acting on one element 18 is increased. Therefore, the elastic member E described above is elastically deformed, and the width dimension of the element 18 is decreased. Become. In this case, since tension is applied to the pressing belt 16, the element 18 enters the bottom side of the grooves A1 and A2, that is, the inner side in the radial direction of the pulleys 2 and 3, and the winding radius of the pressing belt 16 is correspondingly increased. , Get smaller.

  On the other hand, in the pulleys 3 and 2 having a large winding radius, since the number of elements 18 fitted in the grooves A2 and A3 is large, the compressive load in the width direction acting on one element 18 is relatively small. Become. For this reason, the deformation amount of the elastic member E described above is reduced, or the deformation is restored by the elastic force, and the width dimension of the element 18 is relatively increased. As a result, the element 18 moves to the opening side of the grooves A1 and A2, that is, to the outside of the pulleys 2 and 3 in the radial direction, and the winding radius of the pressing belt 16 is increased accordingly. Therefore, even if the movable range of each movable sheave 6, 12 or the change range of the width dimension of the grooves A 1, A 2 is defined, the change width of the transmission ratio, that is, the transmission ratio width is determined by the movable range and the change range. Beyond that, the width of the element 18 increases as the width changes as described above. Therefore, when the continuously variable transmission according to the present invention is used in a vehicle, the fuel consumption and power performance of the vehicle can be improved.

  By the way, since the elastic deformation of the element 18 described above is caused by the deformation of the elastic deformation portion constituted by the elastic member E or the like, the deformation mode of the element 18 is made different depending on the shape of the elastic deformation portion. Can do. For example, when the shape of the elastic deformation portion is a so-called tapered shape indicated by a broken line in FIG. 4 described above, the amount of deformation on the inner side in the radial direction of the lower side in FIG. It becomes larger with respect to the amount of deformation.

  Such deformation corresponds to the deformation of the pulleys 2 and 3. That is, the rigidity of the pulleys 2 and 3 is large on the inner peripheral side in the radial direction and relatively small on the outer peripheral side, so that the contact surfaces 7, 8, 13, and 14 of the pulleys 2 and 3 are illustrated in FIG. As shown in FIG. 6, the reaction force from the element 18 may cause deformation such that the groove width widens like a two-dot chain line. In that case, the contact areas (flank surfaces) 23, 24 of the element 18 are contact surfaces 7, 8, 13 and 14 can be followed to contact and transmit torque. In other words, so-called lower contact between the pulleys 2 and 3 and the element 18 can be suppressed, durability of the pressing belt 16 and the pulleys 2 and 3 can be improved, and further, power transmission loss can be reduced. There are advantages such as.

  The present invention has been described in detail by taking the belt-type continuously variable transmission 1 as an example, but the specific configuration is not limited to the above-described embodiment, and there are design changes and the like without departing from the scope of the present invention. Are also included in the scope of the present invention. Moreover, although the said Example demonstrated the case where the belt-type continuously variable transmission 1 incorporating a press belt was applied for vehicles, it is applicable also to mechanical devices other than a vehicle.

1 is a plan view conceptually showing a belt type continuously variable transmission according to an embodiment of the present invention. It is the side view which showed notionally the belt type continuously variable transmission in the said Example. It is a side view which shows the movement locus | trajectory of the element which is a component of the press belt used for the said belt-type continuously variable transmission. It is sectional drawing in the width direction of the said press belt. It is a figure explaining the effect | action at the time of power transmission about the press belt of the belt-type continuously variable transmission which concerns on the said Example, (a) shows the state before the element of a press belt compresses elastically in the width direction, ( b) is a cross-sectional view showing a state after compression elastic deformation. It is sectional drawing explaining the state which the press belt of the belt-type continuously variable transmission which concerns on the said Example compresses elastically.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Continuously variable transmission, 2 ... Primary pulley, 3 ... Secondary pulley, 7, 8, 13, 14 ... Inclined surface (contact surface) as a groove formation surface, 16 ... Press belt, 17 ... Ring (hoop), 18 ... Element (block), 20 ... Base part, 21 ... Neck part, 22 ... Presser part, 23,24 ... Contact area (flank surface), 30 ... Dimple, 31 ... Hole, A1, A2 ... Groove, E ... Elastic member.

Claims (5)

A belt in which a large number of plate-like elements arranged in an annular shape in a stacked state are bundled by a ring is wound around a driving pulley and a driven pulley that can change the width of the groove, and the element is placed in the groove. In the belt-type continuously variable transmission that transmits torque with frictional force by being pinched by the pulley and sets a gear ratio according to a winding radius of the belt with respect to the driving pulley and the driven pulley,
A belt-type non-belt characterized in that an elastically deformable portion that is more elastically deformable than the both end portions is provided at least in the width direction of the element at a portion closer to the center than both end portions that contact the pulley of the element Step transmission.   The belt-type continuously variable transmission according to claim 1, wherein the elastically deforming portion is formed of a material having a smaller elastic coefficient than a material forming the both end portions.   The belt-type continuously variable transmission according to claim 1, wherein the elastically deforming portion is provided at a central portion in the width direction of the element.   The elastically deforming portion is formed in a tapered shape in which the width of the driving pulley or the driven pulley is wide on the rotation center side while being sandwiched in the groove, and the width is gradually narrowed on the opposite side. The belt-type continuously variable transmission according to any one of claims 1 to 3.   The belt-type continuously variable transmission according to any one of claims 1 to 4, wherein the elastically deforming portion is provided at a position deviating in a width direction with respect to the ring wound around the element. .

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