JP2003120758A - Belt for continuously variable transmission - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce a lateral load applied to a nose when a metal element bites a drive pulley without increasing a load applied on a metal ring assembly. SOLUTION: At a front and a rear surfaces of the metal element 32, the nose 43f and a hole 43r to be engaged with each other are formed. Relation between a first clearance C1 between the nose 43f and the hole 43r and a second clearance C2 between a lower surface 45 of an ear part and an upper surface of the metal ring assembly 31 is set to satisfy 1.7<C2/C1<6.5. A large lateral load applied on the nose 43f when the metal element 32 bites the drive pulley is thus prevented without increasing the load applied on the metal ring assembly 31. Durability of the metal element 32 is thus improved.

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a belt for a continuously variable transmission in which a plurality of metal elements are supported on a pair of metal ring assemblies. 2. Description of the Related Art Such a belt for a continuously variable transmission is known, for example, from JP-A-7-12177 and JP-A-2617784. [0003] Japanese Unexamined Patent Application Publication No. 7-12177 discloses a technique in which the clearance between the lower surface of the ear portion and the upper surface of the metal ring assembly is defined so that the clearance between the metal ring assembly and the chord portion of the metal belt is reduced. The rolling degree of freedom of the metal element is limited to reduce the disturbance of the posture when the metal element bites into the drive pulley from the slack-side chord, thereby preventing wear and improving efficiency. [0004] Further, in Japanese Patent No. 2617784, the length of the pulley contact surface of the metal element and the shape of the lower end portion of the pulley contact surface are determined by the inclination angle of the pulley contact surface of the metal element. Defined based on the relationship with the left and right widths, return to the normal position when the metal element rolls with respect to the metal ring assembly, and set the metal ring assembly so that the saddle surface of the metal element does not exceed the specified height It prevents an excessive load from being applied to the lower surface of the body. [0005] By the way, the metal element has a cylindrical nose and a cylindrical hole on the front surface and the rear surface of the ear portion, respectively, and the hole of the front metal element has a rear hole. The relative positioning between adjacent metal elements is performed by loosely fitting the nose of the metal element. As will be described later in the embodiment, it is known that the metal element is largely displaced in the left-right direction when it bites into the drive pulley from the slack-side chord, so that it is fitted into the hole of the front metal element. However, there is a problem that a large load is generated on the nose of the rear metal element, and durability is reduced. On the other hand, in the above-described conventional device, the posture of the metal element is corrected by contact between the upper surface of the metal ring assembly and the lower surface of the ear portion, or by contact between the lower surface of the metal ring assembly and the saddle surface. However, since the load acting on the nose is not taken into account, there is a concern that the durability of the nose may be adversely affected. The present invention has been made in view of the above circumstances, and has as its object to reduce a lateral load acting on a nose when a metal element bites into a drive pulley. In order to achieve the above object, according to the first aspect of the present invention, a plurality of element bodies and ears are formed with a pair of ring slots interposed therebetween. And a pair of metal ring aggregates respectively fitted into the ring slots, the belt for a continuously variable transmission that transmits a driving force by being wound around a drive pulley and a driven pulley. One and the other of the nose and the hole are formed on the front and rear surfaces of the metal element, and in the case where the nose and the hole of the adjacent metal element are fitted to each other, a first clearance C1 between the nose and the hole,
A belt for a continuously variable transmission is proposed, in which the relationship between the lower surface of the ear portion and the second clearance C2 between the upper surface of the metal ring assembly and the second clearance C2 satisfies 1.7 <C2 / C1 <6.5. According to the above configuration, the relationship between the first clearance C1 between the nose and the hole and the second clearance C2 between the lower surface of the ear portion and the upper surface of the metal ring assembly is 1.7 <C2 / C1 <6. .5, it is possible to prevent a large load in the left-right direction from being applied to the nose of the ear portion when the metal element bites into the drive pulley, thereby improving the durability of the metal element. Embodiments of the present invention will be described below based on embodiments of the present invention shown in the accompanying drawings. 1 to 7 show one embodiment of the present invention. FIG. 1 is a skeleton diagram of a power transmission system of a vehicle equipped with a continuously variable transmission, and FIG. 2 is a partial perspective view of a metal belt. 3 is a three-dimensional enlarged view of FIG. 2, FIG. 4 is a graph showing the relationship between the phase of the metal element and the displacement in the left-right direction, FIG. FIG. 6 shows that when the first clearance is fixed,
FIG. 7 is a graph showing a change in the lateral load of the nose with a change in the second clearance, and FIG. 7 is a graph showing a change in the lateral load of the nose with a change in the first clearance when the second clearance is fixed. FIG. 2 shows the definitions of the front-back direction, left-right direction, and up-down direction of the metal element used in this embodiment. FIG. 1 shows a schematic structure of a metal belt type continuously variable transmission T mounted on an automobile. An input shaft 3 connected to a crankshaft 1 of an engine E via a damper 2 includes a starting clutch 4. Is connected to the drive shaft 5 of the metal belt-type continuously variable transmission T via the. The drive pulley 6 provided on the drive shaft 5 includes a fixed pulley half 7 fixed to the drive shaft 5,
A movable pulley half 8 that can be brought into contact with and separated from the fixed pulley half 7;
Is urged toward the fixed pulley half 7 by hydraulic pressure acting on the pulley half. A driven pulley 11 provided on a driven shaft 10 arranged in parallel with the drive shaft 5
Has a fixed-side pulley half 12 fixed to the driven shaft 10 and a movable-side pulley half 13 that can be moved toward and away from the fixed-side pulley half 12. It is urged toward the fixed pulley half 12 by the hydraulic pressure acting on the oil chamber 14. A pair of left and right metal ring assemblies 3 is provided between the drive pulley 6 and the driven pulley 11.
A metal belt 15 supporting a large number of metal elements 32 is wound around 1, 31 (see FIG. 2). Each metal ring assembly 31 has 12 metal rings 33.
... are laminated. A forward drive gear 16 and a reverse drive gear 17 are rotatably supported on the driven shaft 10. The forward drive gear 16 and the reverse drive gear 17 are selectively driven by a selector 18. 10 can be combined. Output shaft 1 arranged in parallel with driven shaft 10
A drive driven gear 20 meshing with the forward drive gear 16 and a reverse driven gear 22 meshing with the reverse drive gear 17 via a reverse idle gear 21 are fixed to 9. The rotation of the output shaft 19 is controlled by the final drive gear 23 and the final driven gear 2.
4, and is transmitted to the drive wheels W, W via left and right axles 26, 26. The driving force of the engine E is the crankshaft 1, the damper 2, the input shaft 3, the starting clutch 4, the drive shaft 5, the drive pulley 6,
The power is transmitted to the driven shaft 10 via the metal belt 15 and the driven pulley 11. When the forward travel range is selected, the driving force of the driven shaft 10 is transmitted to the output shaft 19 via the forward drive gear 16 and the forward driven gear 20, and causes the vehicle to travel forward. When the reverse travel range is selected, the driving force of the driven shaft 10 is transmitted to the output shaft 19 via the reverse drive gear 17, the reverse idle gear 21 and the reverse driven gear 22, and causes the vehicle to travel backward. At this time, the hydraulic pressure acting on the oil chamber 9 of the drive pulley 6 and the oil chamber 14 of the driven pulley 11 of the metal belt type continuously variable transmission T is controlled by a hydraulic control unit U2 operated by a command from the electronic control unit U1. , The speed ratio is adjusted steplessly. That is, if the oil pressure acting on the oil chamber 14 of the driven pulley 11 is increased relative to the oil pressure acting on the oil chamber 9 of the drive pulley 6, the groove width of the driven pulley 11 decreases and the effective radius increases. Accordingly, the groove width of the drive pulley 6 increases and the effective radius decreases, so that the metal belt type continuously variable transmission T
Changes continuously toward LOW. Conversely, if the oil pressure acting on the oil chamber 9 of the drive pulley 6 is relatively increased with respect to the oil pressure acting on the oil chamber 14 of the driven pulley 11, the groove width of the drive pulley 6 decreases and the effective radius increases. Since the groove width of the driven pulley 11 increases and the effective radius decreases, the speed ratio of the continuously variable transmission T changes steplessly toward OD. As shown in FIGS. 2 and 3, a metal element 32 formed by stamping from a metal plate material has a substantially trapezoidal element body portion 34 and a metal ring assembly 31,
A neck 36 is located between a pair of left and right ring slots 35 in which the fitting 31 is fitted, and a substantially triangular ear 37 connected to the upper part of the element body 34 via the neck 36. A pair of pulley contact surfaces 39 and 3 that can abut on the V surfaces of the drive pulley 6 and the driven pulley 11 are provided on the left and right outer ends of the element body 34.
9 is formed. A pair of front and rear main surfaces 40f, 40r which are orthogonal to the traveling direction and are parallel to each other are formed on the front side and the rear side in the traveling direction of the metal element 32. Is formed with an inclined surface 42 via a locking edge 41 extending in the left-right direction. Further, the metal elements 32, 3 adjacent in front and rear are
In order to join the two, the front surface of the ear portion 37 (the front main surface 40
f) and a rear surface (rear main surface 40r) are each formed with a nose 43f and a hole 43r having a circular cross section that can be loosely fitted to each other. Between the nose 43f and the hole 43r,
A first clearance C1 corresponding to the radius difference is formed. The lower and upper edges of the ring slots 35, 35 are saddle surfaces 44, 44 and ear portion lower surfaces 45, 45, respectively.
The lower surfaces of the metal ring assemblies 31, 31 abut against the saddle surfaces 44, 44, and the upper surfaces have a second clearance C2 between the lower surfaces 45, 45 of the ear portions. As shown in FIG. 4, with the rotation of the metal belt 15, the metal element 32 periodically circulates through the driven pulley 11, the return string, the drive pulley 6, and the forward string, and from the return string to the drive pulley. 6 is largely displaced in the left-right direction when biting (see a). The reason is,
At the return string, the pushing force between the adjacent metal elements 32 disappears, so that the posture is likely to be unstable, and furthermore, the misalignment between the drive pulley 6 and the driven pulley 11 (shift of the center line of both pulleys in the left-right direction). This causes the metal element 32 to move in the left-right direction.
As described above, when the metal element 32 is largely displaced in the left-right direction, the hole 43r of the ear portion 37 of the metal element 32 is formed.
A large load acts on the nose 43f that fits into the nose, which causes a decrease in durability. The broken line in FIG. 5 shows the change in the lateral load acting on the nose 43f. When the return string is engaged with the drive pulley 6, a large lateral load instantaneously acts on the nose 43f. (See section b). The solid line in FIG. 5 shows a change in the V-plane load (the load acting between the V-plane of the pulleys 6 and 11 and the pulley contact surfaces 39 and 39 of the metal element 32). FIG. 6 is a graph showing the first clearance C1.
(Radius difference between nose 43f and hole 43r) is C1 =
The second clearance C is fixed at 0.082 mm.
The nose 43 at the entrance of the drive pulley 6 when 2 (the distance between the upper surface of the metal ring assembly 31 and the lower surface 45 of the ear portion) is changed from 0.14 m to 0.84 mm.
It shows the change in the lateral load applied to f. Second
The reason why the minimum value of the clearance C2 is 0.14 mm is as follows.
When the second clearance C2 is 0.14 mm or less, the upper surface of the metal ring assembly 11 interferes with the ear part lower surface 45 at the outlets of the pulleys 6 and 11, and the metal ring assembly 11
This is because the durability is adversely affected. The second clearance C2 is 0.54 mm
As described above, the load in the left-right direction applied to the nose 43f sharply increases. Therefore, a preferable range of the second clearance C2 is 0.14 mm <C2 <0.54 mm. At this time, the first clearance C1 = 0.082
The ratio of the second clearance C2 to mm is 1.7 <C2 / C1 <6.5. That is, the first clearance C1 = 0.082 mm
1. The ratio C2 / C1 of the second clearance C2 to 1.
If it is set in the range of 7 to 6.5, the metal ring assembly 1
While avoiding interference between the upper surface of 1 and the lower surface 45 of the ear part,
The lateral load applied to the nose 43f can be prevented from suddenly increasing, and the durability can be improved. Incidentally, the graph of FIG. 7 shows that the first clearance C2 is fixed at C1 = 0.46 mm and the first clearance C2 is fixed at 0.46 mm.
It shows the change in the lateral load applied to the nose 43f at the entrance of the drive pulley 6 when the clearance C1 is changed from 0.04 m to 0.12 mm. The reason why the minimum value of the first clearance C1 is set to 0.04 m is that when the first clearance C1 becomes 0.04 mm or less, a galling occurs between the nose 43f and the hole 43r at the exit of the driven pulley 11. . The first clearance C1 is 0.10 mm
As described above, the load in the left-right direction applied to the nose 43f sharply increases. Therefore, a preferable range of the first clearance C1 is 0.04 mm <C1 <0.10 mm. Although the embodiments of the present invention have been described above, various design changes can be made in the present invention without departing from the gist thereof. For example, in the embodiment, the nose 43f is provided on the front surface of the ear portion 37 and the hole 43r is provided on the rear surface. However, the positional relationship between the nose 43f and the hole 43r can be reversed. As described above, according to the first aspect of the present invention, the first clearance C between the nose and the hole is provided.
1 and the second clearance C2 between the lower surface of the ear part and the upper surface of the metal ring assembly are 1.7 <C2 / C
Since 1 <6.5 is satisfied, a large left-right direction load is prevented from being applied to the nose of the ear portion when the metal element bites into the drive pulley, and the durability of the metal element can be increased.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a skeleton diagram of a power transmission system of a vehicle equipped with a continuously variable transmission. FIG. 2 is a partial perspective view of a metal belt. FIG. FIG. 4 is a graph showing the relationship between the phase of the metal element and the displacement in the left-right direction. FIG. 5 is a graph showing the change in the load of the nose in the left-right direction with respect to the phase of the metal element. FIG. 7 is a graph showing a change in the lateral load of the nose with a change in the second clearance. FIG. 7 is a graph showing a change in the lateral load of the nose with a change in the first clearance when the second clearance is fixed. Explanation 6 Drive pulley 11 Driven pulley 31 Metal ring assembly 32 Metal element 34 Element main body 35 Ring slot 36 Neck 37 Ear 43f Nose 43r Lumpur 45 lower ear surface

Claims (1)

1. A plurality of metal elements (32) having an element body (34) and an ear (37) formed with a pair of ring slots (35) interposed therebetween, and a ring slot (35). 35) a belt for a continuously variable transmission, which comprises a pair of metal ring assemblies (31) fitted respectively to the drive pulley (6) and the driven pulley (11) and transmits a driving force. The front and rear surfaces of each metal element (32) have a nose (4
3f) and one of the holes (43r) are formed, and the nose (43f) and the hole (43r) of the adjacent metal element (32) are fitted to each other. 43r) and the relationship between the first clearance C1 between the ear part lower surface (45) and the upper surface of the metal ring assembly (31) satisfies 1.7 <C2 / C1 <6.5. A belt for a continuously variable transmission, comprising: