JP2014142040A - Pulley structure of belt continuously variable transmission - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pulley structure of a continuously variable transmission capable of improving rigidity without increasing the axial length and weight of a movable sheave of an assembly structure.SOLUTION: The pulley structure of a belt continuously variable transmission 1 includes: a fixed sheave 10 with a pulley 6, around which a belt 8 is wound, being integral with a rotational shaft 9; and a movable sheave 11 fitted into the fixed sheave 10 to move in an axial direction so as to approach or separate from the fixed sheave 10, and also includes a hydraulic chamber 17 pressing the movable sheave 11 toward the fixed sheave 10 and provided on an opposite side to a surface 11p of the movable sheave 11 facing the fixed sheave 10. An axially protruding cylindrical portion 20 is formed integrally with an outer circumference of a surface 11b of the movable sheave 11 closer to the hydraulic chamber, and a cylinder member 16 in slidable contact with an inner circumferential surface of a cylindrical member 13 that forms the hydraulic chamber 17 with a liquid tight state kept therebetween is tightly fitted into the cylindrical portion 20 so as to be integrated with the cylindrical portion 20.

Description

  The present invention relates to a pulley structure for a belt-type continuously variable transmission that changes a gear ratio by changing a belt winding radius, and more particularly to a movable sheave structure that approaches or moves away from a fixed sheave.

  The belt type continuously variable transmission can change the effective diameter of the pulley, that is, the belt winding diameter, by changing the groove width of the pulley around which the power transmission belt is wound, thereby controlling the gear ratio steplessly. It is a transmission that can. Specifically, each pulley on the drive side and the driven side is formed by a fixed sheave and a movable sheave that moves relative to the fixed sheave in the axial direction of the pulley shaft. In addition, an actuator is provided that applies an axial load to the movable sheave using, for example, hydraulic pressure. Then, the movable sheave is pressed and moved by the actuator in the axial direction of the pulley shaft, and the belt groove winding width is changed by changing the groove width of the pulley groove formed in the portion where the fixed sheave and the movable sheave of each pulley face each other. The hook diameter can be continuously changed.

  Patent Document 1 discloses an invention relating to the belt type continuously variable transmission as described above. The conical disk-type winding transmission device described in Patent Document 1 is coupled to an input shaft, a conical disk integrally formed with the input shaft, and movable in the axial direction with respect to the input shaft. And the other conical disk (movable sheave). The movable sheave has a boss formed radially outward and on the side opposite to one of the conical discs, and a cylindrical annular wall extending in the axial direction is firmly coupled to the outer peripheral side of the boss. Yes. A pressing piston is disposed between the inner surface of the annular wall and the outer peripheral surface of the flange that is provided on the movable sheave and is movably fitted to the input shaft. The movable sheave is configured to be movable relative to the pressing piston. A pressing chamber (hydraulic chamber) is formed between the annular wall, the movable sheave, and the pressing piston, and the movable sheave moves in the axial direction when pressure oil is supplied to the hydraulic chamber.

JP 2000-27959 A

  In the continuously variable transmission described in Patent Document 1 described above, the movable sheave constituting the hydraulic chamber and the annular wall are formed separately, so that they are formed in a single structure. It is said that machining costs can be reduced because of less cutting. However, the configuration described in Patent Document 1 is a configuration in which an annular wall is fitted from the outer peripheral side to a stepped portion in which the outer peripheral portion of the movable sheave is cut out in a rectangular cross section, and the annular wall is attached to the movable sheave. Even if they are in close contact with each other, they are separate members from the movable sheave, so that they do not particularly act to increase the rigidity of the movable sheave. Therefore, since the shape of the movable sheave becomes a simple conical disk shape, the bending rigidity with respect to the reaction force caused by clamping the belt must be lowered. If the movable sheave is formed thick in order to eliminate such inconveniences, the boss portion for fitting with the rotating shaft becomes longer accordingly, so the axial length and weight of the movable sheave eventually increase. There is a possibility that.

  The present invention has been made paying attention to the above technical problem, and provides a pulley structure for a continuously variable transmission that can improve rigidity without increasing the axial length and weight of the movable sheave of the assembly structure. It is intended to do.

  In order to achieve the above object, the invention according to claim 1 is characterized in that the pulley around which the belt is wound moves in the axial direction so that the fixed sheave integrated with the rotating shaft and the fixed sheave approach or separate from the fixed sheave. The movable sheave fitted in this way, and a hydraulic chamber that presses the movable sheave toward the fixed sheave is provided on the opposite side of the surface of the movable sheave facing the fixed sheave. In the pulley structure of the continuously variable transmission, a cylindrical portion protruding in the axial direction is integrally formed on the outer peripheral portion of the surface of the movable sheave on the hydraulic chamber side, and the inner periphery of the cylindrical member forming the hydraulic chamber A cylinder member that is in sliding contact with the surface while maintaining a fluid-tight state is closely fitted to the cylindrical portion so as to be integrated with the cylindrical portion.

  According to a second aspect of the invention, in the first aspect of the invention, the cylinder member is press-fitted on the inner peripheral side of the cylindrical portion so as to be in close contact with the inner peripheral surface of the cylindrical portion. It is a pulley structure of a continuously variable transmission.

  According to a third aspect of the invention, in the first or second aspect of the invention, the cylindrical portion is formed further on the outer peripheral side than the outermost peripheral position where the belt is wound around the outer peripheral portion of the movable sheave. This is a pulley structure for a belt type continuously variable transmission.

  According to the present invention, the cylindrical portion protruding in the axial direction is integrally formed on the outer peripheral portion of the surface of the movable sheave on the hydraulic chamber side, and the liquid-tight state is maintained on the inner peripheral surface of the cylindrical member forming the hydraulic chamber. The cylinder member slidably brought into contact with the cylindrical portion is fitted into the cylindrical portion so as to be integrated with the cylindrical portion. When the thrust toward the fixed sheave is applied to the movable sheave and the belt is sandwiched between the sheaves, the bending moment acting on the movable sheave is increased by the reaction force caused by the pulley pinching the belt. On the other hand, the movable sheave is formed in a state in which the cylindrical portion protrudes in the axial direction, so that its section modulus (or section moment of inertia) increases. As a result, even if the bending moment associated with pinching the belt is large, the deformation of the movable sheave can be prevented or suppressed due to the high rigidity of the movable sheave. In other words, since the cylindrical portion is integrally formed by projecting in the axial direction on the outer peripheral portion of the surface of the movable sheave in the hydraulic chamber, the cylindrical portion increases the rigidity, and as a result, the thickness of the movable sheave itself is particularly increased. It is not necessary to increase the thickness, and accordingly, an increase in the axial length and weight of the movable sheave can be avoided or suppressed.

  Moreover, according to this invention, the cylinder member is press-fitted on the inner peripheral side of the cylindrical portion so as to be in close contact with the inner peripheral surface of the cylindrical portion. The cylinder member is pressed more firmly against the inner peripheral surface of the cylindrical part by the centrifugal oil pressure generated in the hydraulic chamber as the oil pressure and the pulley rotate, and as a result, the cylinder member is surely prevented from loosening and oil pressure leakage. Or it can be suppressed.

It is a fragmentary sectional view which shows the specific example of the belt-type continuously variable transmission which concerns on this invention. It is the schematic for demonstrating a power transmission path | route when the belt type continuously variable transmission which concerns on this invention is mounted in a vehicle. It is a fragmentary sectional view which shows the state in which the belt is wound on the outermost periphery position in the specific example of the movable sheave concerning this invention.

  Next, a specific example of the pulley structure of the belt type continuously variable transmission according to the present invention will be described. FIG. 2 shows a power transmission path when the belt type continuously variable transmission according to the present invention is mounted on a vehicle. The belt type continuously variable transmission 1 receives power from a power source 2 such as an engine or an electric motor. The transmitted torque is changed and output to the wheel 5 through the counter gear unit 3 and the differential gear 4 while changing the transmitted torque.

  The basic configuration of the belt-type continuously variable transmission 1 is the same as that conventionally known. The primary pulley 6 that is rotated by transmission of power from the power source 2 and the rotation center axis of the primary pulley 6 are mutually connected. A secondary pulley 7 that is arranged in parallel and rotates when power is transmitted from the primary pulley 6, and a belt 8 that is wound around the pulleys 6 and 7 and transmits power is configured. Since the primary pulley and the secondary pulley have substantially the same configuration, in the following description, the primary pulley will be described as an example for convenience.

  The primary pulley 6 includes a fixed sheave 10 that is formed integrally with the input shaft 9 and a movable sheave 11. As shown in FIG. 1, both end portions of the input shaft 9 are rotatably held by bearings 12a and 12b fitted in a housing (not shown). The inner ring of the bearing 12b is pressed and fixed by the lock nut 14 in the axial direction against the wall surface of the boss portion of the input shaft 9 together with a cylinder (cylindrical member) 13 which will be described later.

  Further, the fixed sheave 10 and the movable sheave 11 constituting the primary pulley 6 have conical (tapered) surfaces 10p and 11p (hereinafter referred to as pulley surfaces) facing each other. A belt 8 is wound around a belt winding groove formed between the opposed pulley surfaces 10p and 11p. The fixed sheave 10 and the movable sheave 11 are configured to transmit power to the belt 8 in accordance with a frictional force based on a clamping pressure for clamping the belt 8.

  The movable sheave 11 is disposed so as to face the fixed sheave 10, can move along the axial direction of the input shaft 9, and is configured to rotate together with the input shaft 9. The movable sheave 11 is integrally formed with a hollow boss portion 11a, and the movable sheave 11 and the input shaft are connected by an unillustrated spline or key between the inner peripheral surface of the boss portion 11a and the outer peripheral surface of the input shaft 9. 9 is connected. By configuring in this way, the movable sheave 11 can be rotated by the torque of the input shaft 9 being transmitted by a spline or a key. Moreover, the movable sheave 11 can move relatively in the axial direction of the input shaft 9 along a spline, a key, or the like.

  A mechanism for moving the movable sheave 11 in the axial direction is provided on the side opposite to the surface facing the fixed sheave 10. In the example shown in FIG. 1, the hydraulic actuator 15 is provided on the back surface of the movable sheave 11. The hydraulic actuator 15 includes a hydraulic chamber 17 which is a section defined by a movable sheave 11, a cylinder (cylindrical member) 13 formed in a hollow shape so as to cover the movable sheave 11, and a cylinder member 16 described later. Yes. Pressure oil is supplied to the hydraulic chamber 17 from an oil pump (not shown) through an oil passage 18 formed in the axial center portion of the input shaft 9 and an oil passage 19 communicating from the oil passage 18 to the outer peripheral side of the input shaft 9. It is configured to be. Therefore, the movable sheave 11 moves in response to the axial load in accordance with the amount of oil supplied to the hydraulic actuator 15 or the hydraulic pressure.

  Further, as shown in FIGS. 1 and 3, a cylindrical portion 20 protruding in the axial direction is integrally formed on the outer peripheral portion of the surface 11 b on the hydraulic chamber side of the movable sheave 11. The cylindrical portion 20 is formed further on the outer peripheral side than the outermost peripheral position where the belt 8 is wound around the outer peripheral portion of the movable sheave 11.

  As shown in FIG. 1, a cylinder member 16 is fitted to the inner peripheral surface 20 a of the cylindrical portion 20. The cylinder member 16 has a cylindrical shape, and the outer peripheral surface of one end portion 16 a thereof is press-fitted into the inner peripheral surface 20 a of the cylindrical portion 20. On the other hand, the other end 16b of the cylinder member 16 is formed in a flange shape, and is fitted to the inner peripheral surface 13a of the cylinder 13 so as to slide in the axial direction of the pulley. Further, a seal ring S for preventing or suppressing pressure oil from leaking from the hydraulic chamber 17 into the case is fitted to the other end 16 b of the cylinder member 16. The cylinder member and the cylindrical portion of the movable sheave may be coupled by welding, for example.

  Next, the operation when the above-described belt type continuously variable transmission 1 is mounted on a vehicle will be described. In the belt type continuously variable transmission 1 shown in FIG. 2, the gear ratio is changed by changing the winding radius of the belt 8 by changing the interval between the sheaves 10, 11 of the primary pulley 6. Further, the secondary pulley 7 applies a clamping pressure at the winding radius of the belt 8 in accordance with the gear ratio. Specifically, by controlling the amount of oil supplied to the hydraulic actuator 15 of the primary pulley 6, the position of the movable sheave 11 is controlled to change the gear ratio, and the hydraulic pressure of the hydraulic actuator 7a of the secondary pulley 7 is controlled. As a result, the thrust in the axial direction of the movable sheave 7b is changed to change the clamping pressure.

  When the vehicle travels normally, the speed ratio is usually set to the speed ratio on the highest speed side (minimum speed ratio). In this case, the winding radius of the belt 8 around the primary pulley 6 is maximized. Therefore, the bending moment acting on the movable sheave 11 is increased by the reaction force caused by the primary pulley 6 sandwiching the belt 8. On the other hand, the movable sheave 11 is formed in a state in which the above-described cylindrical portion 20 extends in the axial direction toward the outermost peripheral side. Therefore, the movable sheave 11 has a cylindrical shape instead of a simple disk shape. The section modulus (or section moment of inertia) increases. As a result, even if the bending moment that accompanies the belt 8 is large, the deformation of the movable sheave 11 can be prevented or suppressed due to the high rigidity of the movable sheave 11. Thus, according to the pulley structure according to the present invention, the cylindrical portion 20 is formed integrally with the outer peripheral portion of the movable sheave 11 so as to protrude in the axial direction. Therefore, it is not necessary to increase the thickness of the movable sheave 11 itself, and accordingly, an increase in the axial length and weight of the movable sheave 11 can be avoided or suppressed.

  Further, if the cylinder member 16 is press-fitted into the inner peripheral side of the cylindrical portion 20, the cylinder member 16 is brought into the cylindrical portion 20 by the hydraulic pressure or the centrifugal hydraulic pressure generated in the hydraulic chamber 17 as the primary pulley 6 rotates. As a result, the cylinder member 16 can be surely prevented or suppressed from loosening, leakage of hydraulic pressure, and the like.

  Note that the pulley structure according to the present invention is not limited to the primary pulley but may be provided in the secondary pulley. In addition, the belt type continuously variable transmission according to the present invention may be configured so that the belt is sandwiched between the fixed sheave and the movable sheave and the power is transmitted by friction between the sheave and the belt. It may be a belt type continuously variable transmission formed of a material and supplied with oil to lubricate them, and is a belt type continuously variable transmission in which a contact surface between each sheave and the belt is coated with a resin material. Also good.

  DESCRIPTION OF SYMBOLS 1 ... Belt type continuously variable transmission, 6 ... Primary pulley, 8 ... Belt, 9 ... Input shaft (rotary shaft), 10 ... (Primary pulley) fixed sheave, 11 ... (Primary pulley) movable sheave, 11p, 12p ... Pulley surface, 13 ... Cylinder (cylindrical member), 16 ... Cylinder member, 17 ... Hydraulic chamber, 20 ... Cylinder part (of primary pulley).

Claims (3)

The pulley around which the belt is wound is constituted by a fixed sheave integrated with the rotating shaft and a movable sheave fitted so as to move in the axial direction so as to approach or separate from the fixed sheave. In the pulley structure of the belt type continuously variable transmission in which the hydraulic chamber that pushes the movable sheave toward the fixed sheave is provided on the side opposite to the surface facing the fixed sheave of the movable sheave,
A cylindrical portion protruding in the axial direction is integrally formed on the outer peripheral portion of the surface of the movable sheave on the hydraulic chamber side,
The cylinder member, which is in sliding contact with the inner peripheral surface of the cylindrical member forming the hydraulic chamber while maintaining a liquid-tight state, is brought into close contact with the cylindrical portion so as to be integrated with the cylindrical portion. A pulley structure for a belt-type continuously variable transmission, characterized in that   The pulley structure for a belt-type continuously variable transmission according to claim 1, wherein the cylinder member is press-fitted on the inner peripheral side of the cylindrical portion so as to be in close contact with the inner peripheral surface of the cylindrical portion.   3. The belt-type continuously variable transmission according to claim 1, wherein the cylindrical portion is formed further on an outer peripheral side than an outermost peripheral position where the belt is wound around an outer peripheral portion of the movable sheave. Pulley structure.

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