JPH08210454A - Calking structure for actuator case in pulley for continuously variable transmission - Google Patents

Abstract

PURPOSE: To improve durability by forming a corner part in the diametric direction outer end of a groove wall of an annular groove into a chamfering shape, so as to reduce a stress concentration factor in the base end of a case calking part, in calking a case of a hydraulic actuator connected to the annular groove formed in the periphery of a movable sheave. CONSTITUTION: A movable sheave 2 is externally inserted to a shaft part of a fixed shave 1 through a ball spline 2a, and by pressing the movable sheave 2 to a side of the fixed sheave 1 by a hydraulic actuator 3, a hook winding diameter of a belt 4, interposed between the sheaves, is changed. In a pulley thus formed, a peripheral surface of the movable sheave 2 is formed into a stepped shape of contracting a diameter, and an end part of a case 32 is calked in an annular groove 20 of this small diametric part, to calk the case connected to the movable sheave 2. A corner part 22 in the diametric direction outer end of a groove wall 21 of the annular groove 20 is formed into a chamfering shape, thus to reduce a stress concentration factor in the base end of a calking part 32a, so as to enhance durability against bending by increasing an internal pressure of the hydraulic actuator 3.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a caulking structure for an actuator case in a pulley for a continuously variable transmission.

[0002]

2. Description of the Related Art A pulley for a continuously variable transmission has a fixed sheave,
It consists of a movable sheave that can move axially with respect to the fixed sheave, and a hydraulic actuator that is provided axially outward of the movable sheave to press the movable sheave toward the fixed sheave side. It is caulked to the annular groove formed on the outer periphery. Conventionally, as a caulking structure for such a case, there has been used an actual flat blade 3-114.
From Japanese Patent No. 657, it is known that a groove wall on the inner side in the axial direction of the annular groove of the movable sheave is provided with a minute taper angle, and a large compressive stress is applied to the caulking portion of the case to increase the pressure resistance. There is.

[0003]

By the way, recently, application of a continuously variable transmission to an automobile equipped with an engine having a large displacement is desired. In this case, it is necessary to increase the internal pressure of the hydraulic actuator. According to this, a large bending stress acts on the caulked portion of the case. The crimping structure of the above-mentioned conventional example does not consider the bending stress although the pressure resistance in the radial direction is increased, and cracking occurs at the proximal end of the crimping part of the case due to repeated bending, and sufficient durability is obtained. I can't get it. In view of the above points, an object of the present invention is to provide a caulking structure of an actuator case that can obtain sufficient durability even when the internal pressure of the hydraulic actuator is increased.

[0004]

In order to achieve the above object,
The present invention relates to a case where a case of a hydraulic actuator provided axially outwardly of a movable sheave of a pulley for a continuously variable transmission is caulked to an annular groove formed on the outer periphery of the movable sheave. It is characterized in that the corner portion at the radially outer end of the groove wall on the axially outer side of the groove is chamfered.

[0005]

[Function] The base end of the caulking portion of the case to be caulked into the annular groove has a chamfered shape corresponding to the chamfered shape of the groove wall corner portion, the stress concentration rate at the base end of the caulking portion is reduced, and the internal pressure of the hydraulic actuator is increased. The durability against bending due to is improved.

[0006]

EXAMPLE A pulley for a continuously variable transmission is as shown in FIG.
A fixed sheave 1, a movable sheave 2 which is axially movable on the shaft portion of the fixed sheave 1 via a ball spline 2a, and a hydraulic actuator 3 provided outside the movable sheave 2 in the axial direction. The actuator 3 presses the movable sheave 2 toward the fixed sheave 1 side, and the winding diameter of the belt 4 sandwiched between the fixed sheave 1 and the movable sheave 2 is changed to the upper half of FIG. It is configured to change as shown in the lower half.

The hydraulic actuator 3 comprises a fixed piston 30 fixed to the shaft portion of the fixed sheave 1, and a cylindrical case 32 defining an oil chamber 31 between the piston 30 and the movable sheave 2. The case 32 is caulked to the movable sheave 2.

The outer peripheral surface of the movable sheave 2 is formed in a stepped shape with a small diameter on the outer side in the axial direction.
The annular groove 20 is formed as clearly shown in FIG. 3, and the end of the case 32 is caulked into the annular groove 20 so that the case 32 is caulked to the movable sheave 2.

The corner portion 22 at the radially outer end of the groove wall 21 on the axially outer side of the annular groove 20 is formed into a chamfered shape.
Therefore, the base end of the caulked portion 32 a of the case 32 has a chamfered shape that matches the corner portion 22.

Various chamfers Lm of 0.2 mm, 0.4 mm, and non-chamfered corners are prepared, and the caulking amount Lk of the case 32 is changed to various pulleys. Was manufactured and the durability test of each pulley was performed, and the results shown in Table 1 below were obtained. Case 3
The material of No. 2 was SPCC and the plate thickness was 3.2 mm. In the durability test, the internal pressure of the hydraulic actuator 3 was set to 40 kg / cm ² , one rotation of the pulley was performed once, and the number of times until oil leakage from the crimped portion 32a and cracks in the crimped portion 32a occurred was measured. went. The maximum internal pressure of the hydraulic actuator 3 is 20 kg / cm ² in practical use, but the internal pressure was set to a very high value of 40 kg / cm ^{2 in} order to shorten the test time.

[0011] Conventionally, the corner portion 22 is not chamfered to prevent leakage, but even if the corner portion 22 is chamfered, leakage can be prevented by increasing the caulking amount Lk, and the corner portion 2
It was found that chamfering No. 2 can significantly improve durability.

When the chamfering amount Lm is 0.1 mm or less, the durability does not improve to the left. When the chamfering amount Lm is 0.5 mm or more, the caulking amount Lk needs to be 2 mm or more to prevent leakage. However, the caulking amount becomes too large and the strength decreases. Therefore, the chamfering amount Lm is 0.1 to 0.5 mm,
It is preferably 0.2 to 0.4 mm.

Further, although the corner portion 22 is chamfered obliquely in the above embodiment, the corner portion 2 is formed as in the embodiment shown in FIG.
2 may be chamfered into a round shape.

[0014]

As is apparent from the above description, according to the present invention, the stress concentration rate at the base end of the caulking portion of the case is reduced, and the durability of the hydraulic actuator against bending due to an increase in internal pressure is improved. To do.

[Brief description of drawings]

FIG. 1 is a sectional view of a pulley for a continuously variable transmission.

FIG. 2 is an enlarged cross-sectional view of a caulking portion of a case showing an embodiment of the present invention.

FIG. 3 is an enlarged sectional view showing another embodiment.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Fixed sheave, 2 Movable sheave 20 Annular groove, 21 Groove wall 22 Corner part, 3 Hydraulic actuator 32 Case, 32a Caulking part

Claims (1)

[Claims] 1. A case in which a case of a hydraulic actuator provided axially outwardly of a movable sheave of a pulley for a continuously variable transmission is caulked to an annular groove formed on the outer periphery of the movable sheave. A caulking structure of an actuator case in a pulley for a continuously variable transmission, characterized in that a corner portion at a radially outer end of an axially outer groove wall of the annular groove is chamfered.