JP2001165191A - Friction engaging device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make torque properly rise up without a delay in the beginning of engagement even when a friction characteristic is lowered down due to abrasion in a wave part, in a wearing engaging device pressure connecting an outer tooth disc spline engaged with an outer member and an inner tooth disc spline engaged with an inner member in an axial direction through a friction material, to be formed with the wave part curved in a wave shape in an axial direction with a peripheral direction serving as a wavelength direction in one disc. SOLUTION: A wave part 10 is formed only in an external peripheral side part in one disc of outer/inner tooth discs 3, 4, for instance, the outer tooth disc 3.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a friction engagement device used as a clutch or a brake for an automatic vehicle transmission.

[0002]

2. Description of the Related Art A friction engagement device includes an external gear disk spline-engaged with an outer member and an internal gear disk spline-engaged with an inner member, and presses the external gear disk and the internal gear disk in the axial direction. Then, torque is transmitted between the outer member and the inner member by frictional engagement.

Conventionally, in such a friction engagement device,
It is known that one of the external tooth disk and the internal tooth disk is constituted by a wave disk curved in an axial direction with the circumferential direction being a wavelength direction (Japanese Patent Laid-Open No. 9-16).
No. 6157, JP-A-9-257058).

[0004] When the wave disk as described above is used,
The wave disk is elastically deformed in the early stage of engagement, and the wave disk presses against another disk. The buffering action by the elastic deformation of the wave portion prevents the sudden rise of torque in the early stage of engagement, and reduces the engagement shock. You. Further, at the time of disengagement, the wave disk is quickly separated from other disks by the elastic restoring force of the wave portion, and dragging is suppressed.

[0005]

By the way, when a wave disk is used, the wave portion always comes into contact with another disk first at the time of engagement, so that the wave portion is liable to be worn and the friction characteristics are reduced. Here, in the conventional wave disk, the wave portion is formed over the entire area in the radial direction of the disk, and therefore, the contact surface pressure of the wave portion with respect to another disk at the time of engagement is low. As a result, if the friction characteristics are reduced due to the wear of the wave portion, the rise of the torque in the early stage of the engagement is delayed, so that a smooth shift is not performed and a shift shock is likely to occur.

SUMMARY OF THE INVENTION In view of the above, it is an object of the present invention to provide a friction engagement device capable of appropriately starting up a torque without delay even at the beginning of engagement even when wear occurs.

[0007]

Means for Solving the Problems In order to solve the above problems,
The present invention includes an external gear disk spline-engaged with an outer member, and an internal gear disk spline-engaged with an inner member, wherein the external gear disk and the internal gear disk are brought into axial contact with each other to frictionally engage with each other. A frictional engagement device for transmitting torque between the outer member and the inner member, wherein one of the external tooth disk and the internal tooth disk is curved in an axial direction with a circumferential direction as a wavelength direction. In the formation of the wave portion, the wave portion is formed only on the outer peripheral portion of the one disk.

According to the present invention, at the initial stage of engagement, one of the disks comes into contact with the other disk at the wave portion and both disks frictionally engage with each other, but since the wave portion is provided only on the outer peripheral side of the disk, Even if the contact surface pressure of the wave portion against other discs increases, the effective radius of the frictional engagement portion increases, and even if the friction characteristics decrease due to the wear of the wave portion, the torque is properly established without delay in the initial stage of engagement. climb. Also, at the time of disengagement, one disk is quickly separated from the other disk by the elastic restoring force of the wave portion, and dragging is suppressed. At the time of full engagement, the wave portion is crushed and the disks come into full contact with each other, so that high torque can be sufficiently transmitted.

[0009]

FIG. 1 shows a hydraulic clutch for an automatic transmission as a friction engagement device. This hydraulic clutch includes a clutch drum 1 as an outer member connected to a power transmission shaft S, and a clutch hub 2 as an inner member integrally formed with a speed change gear G supported on the power transmission shaft S. In the clutch drum 1, a plurality of external teeth discs 3 are spline-engaged with spline portions 1a formed on the clutch drum 1 by outer teeth 3a, and inner teeth are formed on spline portions 2a formed on the clutch hub 2. The plurality of internal gear disks 4 that engage with the spline at 4a are alternately arranged in the axial direction.

With the opening direction of the clutch drum 1 being the axially outer side, the outermost toothed disk 3 in the axially outermost direction is prevented from falling off from the clutch drum 1 by the circlip 5.
A piston 6 is provided in the clutch drum 1 so as to face the axially innermost external tooth disk 3. A power transmission shaft S is provided in a hydraulic chamber 7 defined between the end wall of the clutch drum 1 and the piston 6. When the pressurized oil is supplied through the oil passage Sa formed in the above, the piston 6 moves outward in the axial direction against the return spring 8, and the external tooth disk 3 and the internal tooth disk 4 are attached to the internal tooth disk 4. The clutch drum 1 and the clutch hub 2 are pressed in the axial direction via the friction material 9 and frictionally engaged with each other.
Is transmitted. Note that lubricating oil is supplied to the disposition portions of the disks 3 and 4 from a lubricating oil passage Sb formed in the power transmission shaft S.

FIG. 2 shows the outer peripheral portion of the external tooth disc 3 on the outer peripheral side.
As shown in FIG. 3, a wave portion 10 that is curved in an axial direction with the circumferential direction being the wavelength direction is formed. In the illustrated example, the number of waves in the wave unit 10 is three, but the number is arbitrary.

The wave section 10 is a lower mold 100 shown in FIG.
It can be easily formed using a press device having the upper die 200 and the upper die 200. The lower mold 100 has an annular work receiver 101 having a seating surface 101a for receiving an inner peripheral portion of the external tooth disk 3, a projection 101b fitted on the inner circumference of the external tooth disk 3, Three lower punches 102 having heights higher than the seating surface 101a are provided at three locations around the periphery, and the lower surface of the upper die 200 is located between the arrangement pitches of the lower punches 102. Let me 3
An upper punch 201 is provided. Thus, upper mold 2
00, the outer peripheral disk 3 is curved downward at the contact point of the upper punch 201 and upwardly curved at the contact point of the lower punch 102. Is formed on the outer peripheral side portion of. In addition, at the circumferential position of the external tooth disc 3 that matches the lower punch 102, the inner peripheral side part is also curved slightly upward, but the inner peripheral side part is almost flat due to spring back, and the formation region of the wave part 10 is It is substantially limited to the outer peripheral side portion of the external tooth disk 3.

The external tooth disk 3 has the wave portion 1 as described above.
When 0 is formed, the external teeth disk 3 is initially set at the time of clutch engagement.
Is pressed against the internal tooth disk 4 while being elastically deformed in the wave portion 10, and a sudden rise in torque at the initial stage of engagement is prevented by a buffering action due to the elastic deformation of the wave portion 10. Since the wave portion 10 is formed only on the outer peripheral side portion of the external tooth disk 3, the contact surface pressure of the wave portion 10 with the internal tooth disk 4 at the initial stage of engagement increases, and the effective radius of the friction engagement portion decreases. Even if the frictional characteristics decrease due to the abrasion of the wave portion 10, the torque rises properly without delay at the initial stage of engagement. Therefore, it is possible to prevent the engine from blowing up due to a delay in the rise of torque in the initial stage of engagement, and to perform a smooth shift. When the clutch is disengaged, the external tooth disk 3 is moved by the elastic restoring force of the wave portion 10 to the internal tooth disk 4.
, And the drag of the clutch is suppressed. still,
At the time of complete engagement, the wave portion 10 is crushed and the disks 3 and 4 come into full contact with each other, so that high torque can be sufficiently transmitted.

In the above-described embodiment, the wave portion 10 is formed on the outer peripheral portion of the external tooth disk 3. However, the same operation and effect can be obtained by forming the wave portion 10 on the outer peripheral portion of the internal tooth disk 4. Can be

In the above embodiment, the present invention is applied to a hydraulic clutch. However, the present invention can be similarly applied to other friction engagement devices such as a hydraulic brake and a mechanical friction clutch.

[0016]

As is apparent from the above description, according to the present invention, even if the friction characteristics are reduced due to the wear of the wave portion,
It is possible to appropriately raise the torque without delay in the early stage of the engagement, and it is also possible to suppress the drag when the engagement is released.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of an example of the apparatus of the present invention.

FIG. 2 is a perspective view of an external tooth disk.

FIG. 3 is an exploded sectional view of an outer peripheral side portion of the external tooth disk.

4A is a perspective view of an apparatus for forming a wave portion in an open state, and FIG. 4B is a cross-sectional view of the apparatus in a clamped state taken along line IVB-IVB in FIG. 4A.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Clutch drum (outer member) 2 Clutch hub (inner member) 3 External tooth disk 4 Internal tooth disk 10 Wave part

Claims (1)

[Claims] 1. An external tooth disk which is spline-engaged with an outer member, and an internal tooth disk which is spline-engaged with an inner member, wherein the external tooth disk and the internal tooth disk are axially pressed against each other to frictionally engage. A frictional engagement device for transmitting torque between the outer member and the inner member, whereby one of the outer tooth disk and the inner tooth disk has a waveform in the axial direction with the circumferential direction as the wavelength direction. A friction engagement device for forming a curved wave portion, wherein the wave portion is formed only on a portion on an outer peripheral side of the one disk.