JPH09257110A - Pulley structure of belt type non-stage transmission - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the pulley structure of a belt type non-stage transmission excellent in durability by which a speed change ratio can be controlled properly and a production cost can be reduced. SOLUTION: A seal member 33 is stuck strongly to a piston member 31 by welding to the piston member 31 by the connection part 34 of the seal member 33 and the twist of the seal member 33 is prevented and durability is improved and a speed change ratio can be controlled properly by reducing the slide resistance between the piston member 31 and the cylinder member 32 by a lip part 35. The precaution cost can be reduced by the simplification of the tip edge shape of the piston member 31 for sticking the seal member 33 and the drop of a required processing accuracy.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pulley structure for a belt type continuously variable transmission.

[0002]

2. Description of the Related Art A belt type continuously variable transmission includes a primary pulley and a secondary pulley provided on a primary shaft and a secondary shaft, which are arranged in parallel with each other, and a drive belt wound between these pulleys. By changing the pulley groove width of each pulley, the ratio of the effective winding diameter of the drive belt with respect to each pulley is changed to continuously change the speed.

Therefore, each pulley, for example, a primary pulley, enables a fixed sheave 10 which is rotationally driven via a clutch or the like as shown in the cross section in FIG. 3, and an axial movement with respect to the fixed sheave 10. Having a movable sheave 20,
Fixed sheave 10 for smoothly variably controlling the pulley groove width L
A plurality of ball grooves 11a, 21a extending in the axial direction are formed in the shaft portion 11 and the boss portion 21 of the movable sheave 20, respectively, and the fixed sheave 10 and the movable sheave 10 are interposed via balls 25 interposed between the opposing ball grooves. It is connected to 20.

A piston member 3 is provided on the rear surface of the movable sheave 20.
1 is fixed, and this piston member 31 constitutes a hydraulic actuator 30 in cooperation with a cylinder member 32 fixed to the shaft portion 11 of the fixed sheave 10, and the hydraulic pressure of the hydraulic actuator 30 is controlled by the accelerator opening degree and the like. Room 3
The pulley groove width L is variably controlled by the movable sheave 20 that moves on the shaft portion 11 by the hydraulic oil supplied to and discharged from the shaft 0A.

Therefore, the piston member 31 has a movable sheave 2
It is necessary to secure a sufficient pressure resistance to 0 and to firmly bond them. A flange portion 24 having an annular groove 23 is formed on the back surface 22 of the movable sheave 20, and the base end of the piston member 31 is formed on the outer periphery of the flange portion 24. The edges 31a are fitted together, and the base edges 31a are joined by caulking in the annular groove 23.

On the other hand, an annular seal installation groove portion 41 for installing the O-ring 40 is formed on the tip end edge 31b of the piston member 31 as shown in an enlarged view of portion B of FIG. 3, and is provided in the seal installation groove portion 41. O-ring 40 is cylinder member 32
By slidingly contacting the inner peripheral surface 32a of the piston member 31
The gap between the cylinder member 32 and the cylinder member 32 is sealed.

Further, as disclosed in Japanese Utility Model Laid-Open No. 62-190160, a movable sheave 20 provided axially movable with respect to a fixed sheave (not shown) as shown in FIG. The hydraulic actuator 30 is formed by integrally forming the member 32 and fitting the piston member 31 whose base end edge is fixed to the shaft portion of the fixed sheave to the cylinder member 32. A seal installation groove portion 41 is formed on the outer peripheral portion of the piston member 31, and a seal member 43 having a convex cross section, that is, a T-shaped cross section disposed in the seal installation groove portion 41 is an inner peripheral surface 32 a of the cylinder member 32. There is one that seals the gap between the piston member 31 and the cylinder member 32 by slidingly contacting the piston member 31.

[0008]

However, in the structure in which the O-ring is arranged in the seal installation groove and the cylinder member and the piston member are liquid-tightly sealed by the O-ring, the O-ring and the cylinder member are Has a relatively large sliding resistance, and when the hydraulic oil is supplied to and discharged from the hydraulic actuator to continuously change the speed, the speed change speed is limited, and the control response of the gear ratio control is limited. That is, when a vehicle equipped with a belt type continuously variable transmission is stopped by abrupt braking while the vehicle is running, there is a case where a shift to the downshift is delayed and the downshift cannot be completed. Further, in the belt type continuously variable transmission, the O-ring is squeezed out or twisted in the gap between the seal installation groove and the cylinder member because the hydraulic pressure supplied to the hydraulic chamber of the hydraulic actuator is set to be relatively high. There are problems such as low durability of the O-ring.

Further, in the structure in which the seal member having a convex cross section is arranged in the seal installation groove portion, the seal member and the cylinder member can be prevented from protruding or twisting into the gap between the seal installation groove portion of the seal member and the cylinder member. Has a large sliding resistance, which may limit the responsiveness of the gear ratio control in the same manner as described above. Further, in both the structures, the O-ring or the seal member is held by the seal installation groove formed on the peripheral edge of the piston member, so that the seal is maintained. The outer peripheral surface of the installation groove and the seal installation groove that slides with the cylinder member require high processing accuracy, and the peripheral edge of the piston member needs to be thickened to form the seal installation groove. There is a problem that processing equipment and processing man-hours for carrying out the process are required, leading to an increase in manufacturing cost.

Therefore, an object of the present invention is to reliably seal the space between the piston member and the cylinder member, to reduce the sliding resistance at the seal portion to improve the responsiveness of the gear ratio control and the durability of the seal member, and the manufacturing cost. It is an object of the present invention to provide a pulley structure of a belt-type continuously variable transmission that can reduce the noise.

[0011]

A pulley structure of a belt type continuously variable transmission according to the present invention for achieving the above object is a fixed sheave and a movable sheave provided respectively on a primary shaft and a secondary shaft arranged in parallel with each other. A cylinder member and a piston member of a hydraulic actuator, which has a pulley having a pulley and a drive belt wound between both pulleys, and jointly controls the movable sheave to change the pulley groove width of each pulley. One of them is fixed to the back of the movable sheave and the other is fixed to the shaft part that is integral with the fixed sheave, and the pulley groove width of each pulley is changed by the variable control of each movable sheave to change the ratio of the winding diameter of the drive belt to each pulley. In a pulley structure of a belt type continuously variable transmission that changes continuously by changing, a piston member whose front edge faces the inner peripheral surface of a cylinder member, and a front end of the piston member And a seal member having a lip portion integrally formed with the joint portion and having a tip elastically contacting the inner peripheral surface of the cylinder member. The seal member is firmly attached to the piston member, twisting is avoided, the durability of the seal member is improved, sliding resistance is reduced, and appropriate gear ratio control is possible, and the tip of the piston member is improved. The required processing accuracy of the edge can be reduced and the manufacturing cost can be reduced.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the pulley structure of a belt type continuously variable transmission according to the present invention will be described below with reference to the drawings in which the pulley is a primary pulley.

As shown in FIG. 1, the primary pulley has a fixed sheave 10 and a movable sheave 20 which are rotationally driven by an engine or the like via a clutch or the like.

The fixed sheave 10 and the movable sheave 20 are formed by the fixed sheave 10 and the movable sheave 20 while holding the drive belt with a predetermined clamping force to transmit torque in order to ensure a smooth continuously variable transmission of the transmission. Since it is necessary to smoothly variably control the pulley groove width L, the sliding portions of the fixed sheave 10 and the movable sheave 20 are axially fitted to the shaft portion 11 of the fixed sheave 10 and the boss portion 21 of the movable sheave 20, which are fitted to each other. A means for forming a plurality of ball grooves 11a, 21a extending in the opposite direction to each other and transmitting torque via a ball 25 interposed between the ball grooves 11a, 21a facing each other is adopted.

On the other hand, a flange portion 24 having an annular groove 23 is formed on the back surface 22 of the movable sheave 20 opposite to the fixed sheave 10, and the base end edge of the substantially cylindrical piston member 31 is formed in the annular groove 23. The piston member 31 is fixed to the back surface 22 of the movable sheave 20 by crimping and coupling 31a.

A substantially bottomed cylindrical cylinder member 32 whose center is fixed to the shaft portion 11 of the fixed sheave 10 is slidably fitted to the piston member 31, and the tip edge 31b of the piston member 31 is fitted. The hydraulic actuator 30 having the hydraulic chamber 30 </ b> A is formed by sealing the space between the piston member 31 and the cylinder member 32 by the seal member 33 provided in the.

The hydraulic chamber 3 of the hydraulic actuator 30
The pulley groove width L is variably controlled by the movable sheave 20 that moves on the shaft portion 11 of the fixed sheave 10 by the hydraulic oil that is supplied and discharged in 0A by being controlled by the accelerator opening degree or the like.

Piston member 3 for mounting seal member 33
1 has a flat plate shape as shown in FIG. 2 in an enlarged view of a portion A, and the substantially annular seal member 33 attached to the front edge 31b is made of an elastic material, for example, rubber, The leading edge 3 along the leading edge 31b of the piston member 31
It has a joint portion 34 having a U-shaped cross section for fixing 1b, and a lip portion 35 formed integrally and continuously with the joint portion 34.

The seal member 33 is the piston member 31.
By welding to the tip edge 31b of the piston member 31
A seal member 33 is fixed to the piston member 31 so as to surround the piston member 31 along the tip edge 31b of the. The sealing member 33 can be fixed to the piston member 31 by molding together with the piston member 31 when the sealing member 33 is molded, so that the sealing member 33 can be easily welded to the piston member 31 simultaneously with molding.

The tip 35a of the lip portion 35 of the seal member 33 fixed to the tip edge 31b of the piston member 31 elastically contacts the inner peripheral surface 32a of the cylinder member 32 and the piston member 31.
And the cylinder member 32 are slidably sealed.

The primary pulley thus constructed is
Since the tip 35a of the lip portion 35 of the seal member 33 makes elastic contact with the inner peripheral surface 32a of the cylinder member 32, compared to the conventional structure in which an O-ring or a seal member having a convex cross-section slidably contacts the inner peripheral surface of the cylinder member. The sliding resistance can be greatly reduced, the smooth variable control of the pulley groove width L can be performed, and the appropriate gear ratio control can be performed.

Further, since the seal member 33 is welded to the piston member 31 by the joint portion 34 having a substantially U-shaped cross section surrounding the tip end edge 31b of the piston member 31, the seal member 33 is firmly fixed integrally with the piston member 31, so that the seal member 33 is a piston. Member 31
The defect such that the seal member 33 escapes from the leading edge 31b or is damaged by being twisted is avoided, and the durability of the seal member 33 is improved.

Further, since the seal member 33 is fixed to the tip edge 31b of the piston member 31 by the joint portion 34 of the seal member 33, it is not necessary to increase the thickness of the tip edge 31b of the piston member 31 for attaching the seal portion. , Tip edge 31
By covering b with the seal member 33, the tip edge 31b of the piston member 31 is allowed to have only a sheet metal forming or a so-called rough grade processing accuracy such as rough cutting, so that the manufacturing cost is greatly reduced. It has effects such as being obtained.

In the above embodiment, the example in which the piston member is provided on the back surface of the movable sheave and the cylinder member is provided on the fixed sheave has been described. However, the piston member is provided on the fixed sheave and the cylinder member is provided on the movable sheave. It is possible to apply the structure in which the seal member is attached to the leading edge of the member, or apply the above configuration to the secondary pulley. The seal member 33 and the piston member 31
The shape of the joint portion with the front edge 31b may be, for example, two L-shaped surfaces other than the present embodiment.

[0025]

According to the pulley structure of the belt type continuously variable transmission according to the present invention described above, the seal member is firmly fixed to the piston member because the seal member is joined and fixed to the tip edge of the piston member by welding. When the pulley groove width is changed, the durability of the seal member is improved by avoiding problems such as damage due to twisting and the like, and the lip elastically contacts the cylinder member to seal the piston member and the cylinder member. A large reduction in sliding resistance is achieved, and smooth variable control of the pulley groove width is possible, enabling appropriate gear ratio control by an appropriate belt type continuously variable transmission. Further, it is not necessary to increase the thickness of the piston member tip edge for mounting the seal member, and simplification is obtained, and the piston member tip edge can be machined at a rough grade such as sheet metal or cutting, thereby reducing the manufacturing cost. It has a peculiar effect of the present invention such as a large reduction and contributes greatly to the industrial field using the belt type continuously variable transmission in combination with the simple structure.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a primary pulley of a belt type continuously variable transmission that explains an embodiment of the present invention.

FIG. 2 is an enlarged view of a portion A in FIG.

FIG. 3 is a sectional view of a primary pulley illustrating a conventional pulley structure.

FIG. 4 is an enlarged view of a portion B in FIG. 3;

FIG. 5 is a sectional view illustrating a conventional pulley structure.

[Explanation of symbols]

 10 Fixed Sheave 20 Movable Sheave 22 Rear Surface 30 Hydraulic Actuator 31 Piston Member 31a Base End Edge 31b Tip Edge 32 Cylinder Member 32a Inner Surface 33 Seal Member 34 Coupling Part 35 Lip Part 35a Tip L Pulley Groove Width

Claims (4)

[Claims] 1. A pulley having fixed sheaves and movable sheaves respectively provided on a primary shaft and a secondary shaft, which are arranged in parallel to each other, and a drive belt wound between the pulleys. One of the cylinder member and the piston member of the hydraulic actuator that jointly controls the movable sheave to change the pulley groove width of each pulley is fixed to the back surface of the movable sheave, and the other is fixed to the shaft portion integrated with the fixed sheave. In the pulley structure of a belt-type continuously variable transmission in which the pulley groove width of each pulley is changed by changing the movable sheave to change the ratio of the winding diameter of the drive belt to each pulley, the tip edge is a cylinder. The piston member facing the inner peripheral surface of the member, the connecting portion that is connected and fixed to the tip edge of the piston member, and the end formed inside the cylinder member integrally with this connecting portion. Pulley structure of a belt-type continuously variable transmission, characterized in that it comprises a sealing member having a lip portion elastically contacts the surface, the. 2. The pulley structure for a belt type continuously variable transmission according to claim 1, wherein a seal member is attached to the piston member by welding to the tip edge of the piston member. 3. The belt type continuously variable transmission according to claim 1, wherein a base end edge of the piston member is fixed to a back surface of the movable sheave, and a cylinder member is fixed to a shaft portion integrated with the fixed sheave. Pulley structure. 4. The pulley structure for a belt type continuously variable transmission according to claim 1, wherein the piston member is fixed to a shaft portion which is integral with the fixed sheave, and the cylinder member is fixed to the back surface of the movable sheave.