JP2001304363A - Piston for high pressure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a piston for use at high pressure made of a sheet plate metal, moldable without a large-sized press, having a thick plate thickness to withstand high pressure use environment and free from such a problem that a seal member is projected onto the low pressure side, cracked or separated by pressure. SOLUTION: The peripheral edge part of a metal plate, which is the base material of the piston is formed in stepped cross-sectional shape, formed of an inner diameter side circumferential surface and an outer diameter side circumferential surface, and a seal member with a lip part which is brought into sliding contact with the inner peripheral surface of a housing is bonded to the peripheral edge part to be integrated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high-pressure piston, and more particularly to a piston structure for sliding a movable pulley of a continuously variable transmission.

[0002]

2. Description of the Related Art In recent years, automatic transmissions (hereinafter, referred to as ATs) that combine a gear set and a torque converter have been employed in transmissions of automobiles.
T) is released from the clutch operation.

[0003] However, AT has been pointed out by problems such as low power transmission efficiency due to slippage of the torque converter, occurrence of shift shock, and time lag of shift, and has overcome these problems. Step transmissions are beginning to be adopted. The continuously variable transmission has advantages such as a quick and smooth shift, a high power transmission rate, and improved fuel efficiency as compared with the AT.

[0004] In particular, a belt-type continuously variable transmission among the continuously variable transmissions will be briefly described. As shown in FIG. 4, the belt-type continuously variable transmission has an input shaft 6 for inputting engine power and a drive wheel. The output shafts 7 for outputting power are disposed in parallel to each other, and each shaft is slid in the axial direction by fixed pulleys 32 and 42 fixed concentrically with the shaft center and the hydraulic pressure of the hydraulic chamber 51. An input side pulley 3 and an output side pulley 4 comprising movable pulleys 31 and 41 are provided, and an endless belt 8 is hung between the input side pulley 3 and the output side pulley 4.

The fixed pulleys 32 and 42 and the movable pulleys 31 and 41 have a substantially conical shape, and abutment surfaces on which the endless belt 8 abuts are inclined so as to approach each other toward the axial center. Therefore, fixed pulleys 32 and 42
By changing the relative positions of the movable pulleys 31 and 41 with respect to, the engagement position of the endless belt 8 changes to the inner diameter side or the outer diameter side. Thereby, the input shaft 6 and the output shaft 7
And the rotation speed ratio can be changed.

The fluid for generating the hydraulic pressure for sliding the movable pulleys 32 and 42 is sealed by a seal member 12 provided at a peripheral end of a metal plate 11 forming the piston 1. Conventionally, a notch groove having a concave cross section is formed on the circumferential surface of the metal plate 11 facing the inner circumferential surface of the housing, and a cross section O or D is formed in the notch groove.
The piston 1 is formed by fitting the ring-shaped seal member 12 having an increased diameter.

[0007]

However, in order to provide a notch groove into which the seal member is fitted, the circumferential end of the peripheral end of the metal plate is once formed thicker than the plate thickness of the metal plate. Further, forming and forming the notch groove requires not only the forming processing cost but also the fitting work,
It had to be expensive.

Further, when the piston in which the seal member is fitted is incorporated in the housing, the seal member is a pressure contact surface between the inner peripheral surface of the housing and the seal member, that is, a pressure contact surface exhibiting the best sealing performance on the seal surface. It needs to be in a state. Therefore, processing of the notch groove formed on the circumferential surface of the metal plate requires a high degree of dimensional accuracy in consideration of the pressed state of the seal member.

In order to overcome this problem, a sealing member provided at the peripheral end of the metal plate is not directly O-shaped or D-shaped, but is provided directly with a sealing member provided with a lip that slides on the inner peripheral surface of the housing. A piston that is adhesively integrated with the peripheral end of the metal plate is conceivable, but in the operating environment, that is, in the hydraulic chamber of the continuously variable transmission, the movable pulley is slid by hydraulic pressure, or the movable pulley is fixed at a desired position. Very high pressure because it must be done.

In the case of a normal AT clutch engagement piston, the pressure is about 2 MPa. However, the piston of a continuously variable transmission has a line pressure for sliding a movable pulley by oil in a hydraulic chamber and a centrifugal force due to rotation. Due to the centrifugal pressure of the oil receiving the force, the pressure becomes about 6 to 8 MPa. Therefore, the piston is required to have pressure resistance, and the sealing member provided at the peripheral end of the metal plate is also sealed well in the high pressure environment. It is required to exhibit its properties.

Therefore, in order to withstand such a high-pressure environment, the metal plate itself must first have rigidity. That is, if the metal plate is bent by the high pressure, the pressure contact state of the seal member may change and the sealing property may become unstable. Therefore, it is necessary to increase the thickness of the metal plate. Also, the circumferential surface of the peripheral end of the metal plate and the inner periphery of the housing are prevented so that the sealing member does not protrude to the low-pressure side (the side opposite to the hydraulic chamber) due to pressure, and does not cause a problem such as cracking or peeling. It is necessary to make the distance from the surface as small as possible.

However, since the metal plate is integrally formed by sheet metal, if the thickness of the metal plate is increased, the peripheral end of the metal plate cannot be punched at one time, and the above-described metal plate having a large thickness cannot be used. It was difficult to mold the plate. Even if punching is possible, if the sealing member is a compression seal such as an O-ring or D-ring, after punching out, cut the notch groove for fitting the sealing member, and further cut the metal plate. Since it is necessary to perform high-precision cutting to reduce the gap between the circumferential surface at the peripheral end and the inner peripheral surface of the housing, the processing cost has been expensive. Further, even in the case of a seal member having a lip portion, a thick metal plate is punched with high precision so that a gap between the circumferential surface of the metal plate peripheral end portion and the housing inner peripheral surface is reduced. Requires the use of a large press so that a thick plate can be punched out, and in any case, the processing cost of the metal plate is extremely high.

In view of the above, according to the present invention, by devising the shape of the peripheral edge of the metal plate, the thickness of the metal plate is increased, the interval between the circumferential surface of the peripheral edge of the metal plate and the inner peripheral surface of the housing is reduced, and the size of the metal plate is increased. It is an object of the present invention to provide a high-pressure piston that can be formed without using a press.

[0014]

In order to solve the above-mentioned problems, the present invention reciprocates in the axial direction relative to the housing within the piston insertion space of the housing having the annular piston insertion space. In a possible annular high-pressure piston, the high-pressure piston has a circumferential end portion formed such that a part of the circumferential surface facing the inner circumferential surface of the housing is close to the inner circumferential surface of the housing. And a seal member having a lip that is bonded and integrated to the peripheral end of the metal plate and that slides on the inner peripheral surface of the housing.

An annular high-pressure piston reciprocally movable in the axial direction relative to the housing within the piston insertion space of the housing having the annular piston insertion space, wherein the high-pressure piston is A metal plate made of sheet metal having a stepped peripheral edge formed by an inner circumferential surface and an outer circumferential surface facing the inner circumferential surface, and adhesively integrated with the circumferential end of the metal plate And a seal member having a lip portion that slides on the inner peripheral surface of the housing.

Further, in the piston insertion space of the housing having the annular piston insertion space, the housing can reciprocate in the axial direction relative to the housing, and the hydraulic pressure from the hydraulic chamber in the piston insertion space can be reduced. An annular high-pressure piston that slides the movable pulley of the continuously variable transmission in the axial direction, wherein the high-pressure piston has an inner circumferential surface and an outer circumferential surface facing the inner circumferential surface of the housing. And a metal plate made of sheet metal having a peripheral end portion having a step shape in cross section formed by, and adhesively integrated with the peripheral end portion of the metal plate,
A seal member having a lip portion that slides on the inner peripheral surface of the housing.

Further, of the peripheral end of the high-pressure piston, the inner circumferential surface is formed by crushing, and the outer circumferential surface is formed by punching.

[0018]

According to the high-pressure piston according to the present invention, the circumferential surface of the peripheral end of the metal plate facing the inner peripheral surface of the housing has a step so that a part of the peripheral surface is close to the inner peripheral surface of the housing. It is formed to have. That is, since the seal member has a stepped shape having an inner circumferential surface and an outer circumferential surface, and a seal member having a lip portion that is in sliding contact with the inner circumferential surface of the housing is adhered (including welding and baking) to a peripheral end thereof.
Since the outer circumferential surface can be formed so that the outer circumferential surface is close to the inner circumferential surface of the housing, and the lip portion is less likely to be pushed into the low pressure side, the protrusion of the seal member can be prevented.

Further, since the peripheral end of the metal plate has a step shape, a large bonding area with the seal member can be obtained, and the seal member is hardly peeled off from the peripheral end of the metal plate.

Furthermore, since the inner peripheral surface of the metal plate is formed by crushing and the outer peripheral surface is formed by stamping at the peripheral end of the metal plate, even when the thickness of the metal plate is large. Once the thickness is reduced by crushing, punching can be performed with the thickness reduced. Therefore, molding is possible without using a particularly large press machine, and versatility is improved.

Further, in order to provide a notch groove into which the compression seal of the O-ring or the D-ring is fitted, the circumferential end of the peripheral end of the metal plate is formed once thicker than the thickness of the metal plate. There is no necessity, and it is not necessary to accurately form a notch groove for fitting the seal member in consideration of the contact surface pressure on the seal surface. Therefore, the processing cost for forming the notch groove can be reduced, and the fitting operation step of fitting the ring-shaped seal member is not required.

Further, since the outer circumferential surface can be formed with high precision by punching, it can be designed to be close to the inner circumferential surface of the housing, and the lip portion of the seal member protrudes toward the low pressure side even in a high pressure environment. Eliminate problems.

[0023]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the drawings. FIG. 1 is a schematic sectional view of a continuously variable transmission into which the piston 1 of the present invention is incorporated, and FIG. 2 is an enlarged sectional view of the piston 1 of the input pulley 3 in FIG.

In FIG. 1, a substantially conical fixed pulley 32 and a housing 2 are fixed to an input shaft 6 to which a rotational force from an engine is input, and a movable pulley 31 slidable in the axial direction on the fixed pulley 32. , Which rotate synchronously with the rotation of the input shaft 6.

The movable pulley 31 has the piston 1 tightly fixed thereto, and the seal member 12 of the piston 1 is in contact with the housing 2. The movable pulley 31, the piston 1, the input shaft 6, and the housing 2 allow the piston of the housing 2 to move. A hydraulic chamber 51 is formed in the insertion space 5.

The inside of the hydraulic chamber 51 can be pressurized by injecting a fluid from a lubrication port 52. When the inside of the hydraulic chamber 51 is pressurized, the movable pulley 31 slides toward the fixed pulley 32 in the axial direction. The gap between the V-shaped grooves formed on the contact surfaces of both pulleys is reduced by the movement.

Movable pulley 31 and fixed pulley 32
The contact surface 33 with which the endless belt 8 abuts has a tapered surface whose cross-sectional shape is open from the axis to the outer radial direction, and is formed by the contact surface 33 of the input side pulley 3. The input pulley 3 and the output pulley 4 are formed by hanging the endless belt 8 on the V-shaped groove and the V-shaped groove formed by the contact surface 43 of the output pulley 4 having substantially the same shape as the input pulley 3. Are linked.

The output pulley 4 has a fixed pulley 42 fixed to the output shaft 7 like the input pulley 3, and a movable pulley 41 slidable in the axial direction is attached to the fixed pulley 42. The housing 2 is fixed to the movable pulley 41 on the output side, and the movable pulley 41 and the output shaft 7 are inserted into the piston insertion space 5 of the housing 2.
Further, a hydraulic chamber 51 formed by the output side piston 1 is formed.

When the output side hydraulic chamber 51 is pressurized, the movable pulley 41 and the output side housing 2 are fixed to the fixed pulley 4.
2 and the distance between the V-shaped grooves formed by the contact surfaces 43 of the fixed pulley 42 and the movable pulley 41 is reduced.

When the rotational force from the engine is input to the input shaft 6, the input pulley 3, the piston 1, and the housing 2 rotate together with the input shaft 6, and the output pulley 4, the output side The housing 2, the output piston 1, and the output shaft 7 rotate. At this time, for example, when the interval between the fixed pulley 32 and the movable pulley 31 on the input side is reduced, the engagement position of the endless belt 8 that contacts the contact surface 33 of both pulleys moves to the outer peripheral side. The diameter up to the mating position increases, and conversely, the fixed pulley 3
When the distance between the endless belt 2 and the movable pulley 31 increases, the engagement position of the endless belt 8 moves to the inner peripheral side, so that the diameter from the shaft center to the engagement position decreases. And the rotational speed ratio of the output shaft 7 is changed.

Next, the high pressure piston of the present invention will be described in detail with reference to an enlarged view of the input side piston 1 shown in FIG.

The piston 1 whose one end is fixed to the movable pulley 31 includes a metal plate 11 and an inner peripheral surface 21 of the housing.
And has a substantially L-shaped cross-section. The metal plate 11 is formed by sheet metal forming.
The peripheral end portion 13 on the inner peripheral surface 21 side of the housing is bent at several places and has a stepped shape formed by an inner peripheral surface 13a and an outer peripheral surface 13b facing the inner peripheral surface 21 of the housing. are doing.

In forming the metal plate 11, even if it is impossible to punch a metal plate having a large thickness at one time, the inner diameter of the metal plate 11 is set to a thickness enough to punch out once. Since the surface 13a is formed by crushing and then the outer circumferential surface 13b is formed by punching, the metal plate 11 having a large thickness can be used without a large press machine.
Is possible. In addition, since the inner circumferential surface 13b is formed by crushing, which is difficult to obtain accuracy, and the outer circumferential surface 13b is formed by punching that can achieve dimensional accuracy, the outer circumferential surface 13b and the inner circumferential surface of the housing are formed. It is possible to perform the molding with high accuracy so that the distance from the mold 21 is as close as possible.

A rubber lip portion 12a is attached to the peripheral end portion 13 of the metal plate 11 having the step shape shown in FIG.
Is sealed and adhered, and slides on the inner peripheral surface 21 of the housing to seal the fluid in the hydraulic chamber 51. That is, when the pressure in the hydraulic chamber 51 becomes high, the lip portion 12a that has received the pressure is pressed against the inner peripheral surface 21 of the housing, and is tightly deformed to exhibit sealing properties. However, if the pressure in the hydraulic chamber 51 is too high, a bulge occurs, which is deformed so as to be pushed to the opposite side (low pressure side) of the hydraulic chamber 51, and a crack is generated in the lip portion 12a. However, the shape of the peripheral end 13 of the metal plate 11 may be stepped, that is,
Since the outer circumferential surface 13b is formed so as to be close to the inner circumferential surface 21 of the housing, the lip portion 12a is less likely to be pushed into the low pressure side, and the phenomenon of protrusion can be prevented. Further, by forming the peripheral end portion 13 in a step shape, the contact area between the seal member 12 and the metal plate 11 increases, so that the peeling phenomenon of the seal member 11 can be prevented.

Further, by pressurizing and depressurizing the hydraulic chamber 51, the piston 1 similarly slides in the axial direction together with the movable pulley 31, so that the lip portion 12a which slides in close contact with the inner peripheral surface 21 of the housing is provided inside the housing. As shown in FIG. 3A, a resin 12c such as PTFE is provided on the contact surface with the peripheral surface 21.
May be adhered or a coating may be applied. With this configuration, the sliding resistance is reduced, the sliding friction is suppressed, the durability of the lip portion 12a is improved, and the rubber lip portion 12a works as a shape reinforcement, and has an effect of suppressing the protrusion phenomenon.

FIGS. 3 (c) through 3 (c) show other embodiments.
(G). FIG. 3B is as described above.
When the outer circumferential surface 13b is not covered with the seal member 12 as in (c), the gap between the outer circumferential surface 13b and the housing inner circumferential surface 21 (not shown) is covered. It is possible to bring the seal member closer by the amount not to
This is effective in preventing the protrusion phenomenon.

Further, as shown in FIG. 3D, after forming the inner circumferential surface 13a by crushing, the outer circumferential surface 13b is formed by punching, and the metal plate circumferential end 13 is formed. Is formed into a stepped shape, and a notch groove 13c is formed to cover the seal member 12, so that the contact area between the peripheral end portion 13 and the seal member 12 increases.
Can be prevented from occurring. In the embodiment, one cut groove 13c is provided, but the present invention is not limited to this, and a plurality of cut grooves 13c may be provided to increase the contact area. Further, FIG.
In the case where the outer circumferential surface 13b is not covered with the seal member 12 as in (e), the gap between the outer circumferential surface 13b and the housing inner circumferential surface 21 (not shown) is brought closer. This is effective in preventing the protrusion of the seal member 12.

As shown in FIGS. 3 (f) and 3 (g), FIGS. 3 (d) and 3 (e) provided with a cut groove 13c are formed, and a half of resin or metal is formed in the cut groove 13c. By inserting the ring 12b made of a metal, the gap between the ring 12b and the inner peripheral surface of the housing (not shown) can be reduced, the phenomenon of protrusion is suppressed, and the contact area of the seal member 12 is increased. Can also be suppressed.
Further, as shown in FIG.
1 (not shown), the sealing member 12 can have a large bonding area.
The peeling phenomenon of the seal member 12 can be suppressed more than (g).

Although the embodiment in which the embodiment of the present invention is applied to a continuously variable transmission has been described above, the present invention is not limited to this, and the structure of the high-pressure piston of the present invention is provided at the peripheral end of a normal non-high-pressure piston. Needless to say, may be applied.

Further, although the cross-sectional shape of the peripheral end 13 of the metal plate 11 is stepped, it is not limited to a complete step-like shape, and a circle facing the housing inner peripheral surface 21 of the peripheral end 13 is not limited. Outer circumferential surface 13 closer to housing inner circumferential surface 21 than inner circumferential surface 13a
It is sufficient that b is formed, and there is no particular limitation in the cross-sectional shape between the inner circumferential surface 13a and the outer circumferential surface 13b.

[0041]

According to the high-pressure piston of the present invention as described above, the peripheral end of the metal plate has a stepped shape,
Since a seal member having a lip portion that slides on the inner peripheral surface of the housing is bonded to the peripheral end portion, the circumference of the peripheral end portion of the metal plate, which is indispensable when an O-ring or a D-ring is applied to the seal member. It is not necessary to form the end of the surface once thicker than the thickness of the metal plate, and to form a notch groove for fitting the seal member with high precision in consideration of the contact surface pressure on the seal surface. Therefore, the processing cost for forming the notch groove can be reduced, and the fitting operation step of fitting the ring-shaped seal member is not required.

Further, since the inner peripheral side surface is formed by crushing the peripheral end portion of the metal plate and the outer peripheral side surface is formed by punching, a thick metal plate is formed by a large press machine. It is possible to mold without using. Therefore, a piston corresponding to a high pressure can be formed at low cost.

Further, since the peripheral end of the metal plate has a stepped shape, a large bonding area with the seal member can be obtained, so that the seal member does not easily peel off from the peripheral end of the metal plate.

Further, since the outer circumferential surface can be designed to be close to the inner circumferential surface of the housing, the distance between the outer circumferential surface and the inner circumferential surface of the housing can be reduced, and the seal can be formed even in a high-pressure environment. The problem that the lip portion of the member protrudes toward the low pressure side can be solved.

[Brief description of the drawings]

FIG. 1 is a sectional view in which a high-pressure piston of the present invention is applied to a continuously variable transmission.

FIG. 2 is an enlarged sectional view of a high-pressure piston according to the present invention.

FIG. 3 is an enlarged sectional view of a peripheral end portion of a high-pressure piston according to another embodiment of the present invention.

FIG. 4 is a sectional view in which a conventional piston is applied to a continuously variable transmission.

[Explanation of symbols]

 Reference Signs List 1 piston (input side) 2 housing 3 input side pulley 4 output side pulley 5 piston insertion space 6 input shaft 7 output shaft 8 endless belt 11 metal plate 12 seal member 12a lip portion 12b ring 12c resin 13 peripheral end portion 13a inner diameter side circle Peripheral portion 13b Outer diameter side peripheral portion 13c Cut groove 21 Inner peripheral surface of housing 31 Movable pulley (input side) 32 Fixed pulley (input side) 33 Contact surface (input side) 41 Movable pulley (output side) 42 Fixed pulley (Output side) 43 Contact surface (Output side) 51 Hydraulic chamber 52 Lubrication port

Claims (4)

[Claims] An annular high-pressure piston reciprocally movable in an axial direction relative to the housing within the piston insertion space of a housing having an annular piston insertion space, wherein the high-pressure piston is provided in a housing. A metal plate made of sheet metal having a peripheral end formed so that a part of the peripheral surface is close to the inner peripheral surface of the housing, and a peripheral end of the metal plate; And a sealing member having a lip portion slidably in contact with the inner peripheral surface of the housing. 2. An annular high-pressure piston reciprocally movable in the axial direction relative to the housing within the piston insertion space of a housing having an annular piston insertion space, wherein the high-pressure piston includes a housing. A metal plate made of sheet metal having a stepped peripheral edge formed by an inner circumferential surface and an outer circumferential surface facing the inner circumferential surface, and adhesively integrated with the circumferential end of the metal plate And a seal member having a lip portion that slides on the inner peripheral surface of the housing. 3. A housing having an annular piston insertion space is reciprocally movable in the axial direction relative to the housing within the piston insertion space, and is configured to relieve hydraulic pressure from a hydraulic chamber in the piston insertion space. An annular high-pressure piston that slides the movable pulley of the continuously variable transmission in the axial direction, wherein the high-pressure piston has an inner circumferential surface and an outer circumferential surface facing the inner circumferential surface of the housing. And a sealing member having a lip portion that is adhesively integrated with the peripheral end portion of the metal plate and has a lip portion that slides on the inner peripheral surface of the housing. A high-pressure piston characterized in that: 4. The peripheral end of the high-pressure piston is formed by crushing an inner circumferential surface and piercing an outer circumferential surface by punching. 2. The high-pressure piston according to 1.