JPH0221895B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a sheet metal piston for an automatic transmission for a private vehicle, which is formed by bending a thin metal plate.

[Conventional technology]

Automobile automatic transmissions use an annular piston C with a short axial dimension and a seal ring groove D around it, as in the hydraulic servo B of the friction material A of the friction engagement element shown in FIG. A seal ring E is fitted into the seal ring groove D. Although this annular piston C can be manufactured by cutting, forging, or other manufacturing methods, it is preferable to manufacture it by pressing from the viewpoint of improving productivity.

By the way, in fields other than automatic transmissions for automobiles, a circular plate 101 as shown in FIG.
A sheet metal piston is produced in which a seal ring groove D is formed by bending the wire into a square shape and fitting another annular member 102 having an L-shaped cross section.

[Problem that the invention seeks to solve]

However, in order to use this sheet metal piston as an annular piston for an automatic transmission for automobiles, it is necessary to form an outer seal ring groove and an inner seal ring groove, which requires fitting the three members. Because it is necessary to do this, it has the disadvantage of poor productivity. Furthermore, when the seal ring groove is formed by a fitting operation, the dimensional accuracy of the seal ring groove is poor, and there is a fear that the sealing performance of the seal ring may be deteriorated.

Furthermore, when manufacturing by pressing, the material is limited to relatively soft materials that can be bent, so when the pressure receiving wall receives hydraulic pressure and the piston pushes the multi-plate clutch, the piston may tilt. This may reduce the sealing performance of the seal ring, and furthermore, the pushing force from the hydraulic pressure and the pushing force from the return spring acting in opposition to it may not work evenly on the surface receiving the pushing force. When the piston is twisted, it becomes impossible to push the friction material evenly, and there is a risk that the friction material may hit one side and burn out.

In order to solve the above-mentioned problems, the present invention is an automatic transmission for automobiles that can accurately integrally mold a piston from a single plate, significantly improving productivity, and increasing the rigidity of the piston and reducing deformation. An object of the present invention is to provide a sheet metal annular piston and a method for manufacturing the same.

[Means for solving problems]

In order to solve the above problems, a first aspect of the present invention includes an annular pressure receiving wall, an outer seal ring groove, and an inner seal ring groove, and receives hydraulic pressure from the pressure wall and engages in frictional engagement. In a sheet metal annular piston of an automatic transmission for an automobile that presses a friction material of an element, the outer seal ring groove is one of the outer seal ring grooves that are folded in the inner radial direction from the outer peripheral edge of the pressure receiving wall portion through the bent portion. a side wall portion of the outer seal ring groove formed in the axial direction from the one side wall portion through the bent portion, and an outer side wall portion formed in the outer radial direction from the bottom wall portion through the bent portion. and the other side wall of the inner seal ring groove, and the inner seal ring groove includes one side wall of the inner seal ring groove that is folded over in the outer radial direction from the inner circumferential edge of the pressure receiving wall via the bent part. , a bottom wall portion of the inner seal ring groove formed in the axial direction from the one side wall portion via the bent portion, and the other of the inner seal ring groove formed in the inner radial direction from the bottom wall portion via the bent portion. A sheet metal annular piston for an automatic transmission for an automobile, characterized in that the pressure receiving part wall part, the outer seal ring groove, and the inner seal ring groove are integrally molded.

In addition, in the method for manufacturing a sheet metal annular piston for an automatic transmission for an automobile, which is the second invention of the present invention, a cylindrical portion connected to the circular flat plate portion is formed by pressing a circular flat plate and bending the edge in the axial direction. In the forming step, the flat plate side of the cylindrical part is folded over the flat plate part to form one side wall part of the outer seal ring groove, and at the same time, the diameter of the tip side of the cylindrical part is reduced to form the outer seal ring groove. a step of forming a bottom wall portion, a step of providing a notch at a predetermined position on the outer circumferential wall surface of the squeezed cylindrical portion, and a step of forming a notch at a predetermined position on the outer circumferential wall surface of the squeezed cylindrical portion, and a step of forming the tip side of the squeezed cylindrical portion in a radial direction with reference to the notch. a step of forming an outer seal ring groove by bending the outer seal ring groove to form the other side wall portion of the outer seal ring groove; a step of forming a recess projecting to one side by pressing in the center of the circular shape; A step of punching out the bottom of the hole, a step of burring the punched protrusion to form an annular flat plate part and a cylindrical part, folding the flat part side of the cylindrical part onto the flat part, and sealing the inner side. forming one side wall of the ring groove and at the same time reducing the diameter of the tip end of the cylindrical part to form the bottom wall of the inner seal ring groove; and a predetermined position on the inner circumferential wall surface of the cylindrical part that has been reduced. an inner seal ring groove, which comprises a step of providing a notch around the inner seal ring groove, and a step of bending the tip side of the cylindrical portion squeezed by a press in a radial direction based on the notch to form the other side wall portion of the inner seal ring groove. It is characterized by having a step of molding.

[Action and effect]

The sheet metal annular piston for an automatic transmission for an automobile according to the first aspect of the present invention has the above-mentioned structure, and the piston can be accurately integrally molded from a single plate, resulting in high productivity. Furthermore, one side wall portion of the outer seal ring groove is folded in the inner radial direction from the outer peripheral edge of the pressure receiving wall portion via the bent portion, and one side wall portion of the outer seal ring groove is folded in the outer radial direction from the inner peripheral edge of the pressure receiving wall portion via the bent portion. By having one side wall of the inner seal ring groove folded over, a rib effect is created and the rigidity of the piston is increased, so the tilting and twisting of the piston is reduced, and the sealing performance of the seal ring is maintained. In addition, since the friction material can be pressed evenly, it is possible to prevent seizure due to uneven contact of the friction material.

Further, since the method for manufacturing a sheet metal annular piston for an automatic transmission for an automobile according to the second aspect of the present invention is mainly constituted by the above-mentioned pressing process, the annular sheet metal piston for an automatic transmission for an automobile is made into one sheet. It can be accurately and easily integrally molded from the shape, and productivity can be significantly improved.

In particular, a notch is provided at a predetermined position on the circumferential wall surface of the squeezed cylindrical portion, that is, the bottom wall of the seal ring, and the tip side of the squeezed cylindrical portion is moved radially with respect to the notch using a press. Since the step of bending to form the other side wall of the outer seal ring groove increases the dimensional accuracy of the bottom wall of the seal ring groove, that is, the dimensional accuracy of the seal ring groove, improving the performance of the piston of the automatic transmission for automobiles. The seal ring groove according to the above can be accurately integrally molded from a single plate.

〔Example〕

Next, the present invention will be explained based on embodiments shown in the drawings.

FIG. 3 shows an embodiment of a sheet metal annular piston for an automatic transmission for an automobile according to the first aspect of the present invention, and shows a sheet metal for an automatic transmission for an automobile having an outer seal ring groove 2 and an inner seal ring groove 3. An annular piston 1 is shown, with an annular pressure receiving wall 4 and an outer seal ring folded radially inward from an outer edge 41 of said pressure receiving wall 4 via a bend to form an outer seal ring groove 2. one side wall portion 21 of the groove;
A bottom wall portion 22 of an outer seal ring groove formed in the axial direction from the one side wall portion 21 via the bent portion, and an outer seal ring groove formed radially outward from the bottom wall portion 22 via the bent portion. and one side wall portion of the inner seal ring groove which is folded radially outward from the inner edge 42 of the pressure receiving wall portion 4 via the bent portion to form the inner seal ring groove 3. 31, a bottom wall portion 32 of an inner seal ring groove formed in the axial direction from the one side wall portion 31 via the bent portion, and an inner seal formed radially inward from the bottom wall portion 32 via the bent portion; and the other side wall portion 33 of the ring groove.

4 and 5 are explanatory diagrams of a method for manufacturing a sheet metal annular piston for an automatic transmission for an automobile.

4A to 4H show the molding process of the outer seal ring groove 2. FIG.

An annular plate 5 is punched out from a plate material and the edges of the annular plate 5 are bent in the axial direction using a press to form an annular flat plate portion 51 and a cylindrical portion 52 continuous to the outer peripheral edge of the flat plate portion. Next, the flat plate portion 51 side of the cylindrical portion 52 is folded over the flat plate portion using a die 61, a punch 62, and an inner die 63 to form one side wall portion 53 of the outer seal ring groove. A cylindrical portion 55 is formed by reducing the diameter of the tip.

Next, a notch 71 having a depth of 0.2 to 0.3 mm is formed at a predetermined position on the outer peripheral wall surface of the compressed cylindrical portion 55 using a notch punch 7. Next, using a press mold 64, the tip side of the cylindrical portion 55, which has been cut down based on the notch 71, is extended in the radial direction to form the bottom wall portion 54 of the outer seal ring groove and the other side wall portion 56 of the outer seal ring groove. Mold.

5A to 5G show the molding process of the inner seal ring groove 3. FIG.

A disk 8 is punched out from a plate material, a recess 81 is formed in the center of the disk by pressing, and the bottom 82 of the recess 81 is punched out.Then, the punched projection is burred to form a circle. An annular flat plate portion 83 and a cylindrical portion 84 are formed.

Next, the flat plate part 83 side of the cylindrical part 84 is cut into the flat plate part 83 using the punch 65, the die 66, and the outer die 67.
At the same time, the distal end side of the cylindrical portion 84 is extended in the axial direction from the inner periphery of the side wall to form a narrowed cylindrical portion 86. Next, a notch 9 is provided at a predetermined position on the inner circumferential wall surface of the squeezed cylindrical portion 86 using a notch punch 7, and then a notch 9 is formed around the tip side of the squeezed cylindrical portion 86 using a press die 68. It is bent in the radial direction based on the reference, and the bottom wall part 88 and the other side wall part 87 of the inner seal ring groove are molded.

As described above, the sheet metal annular piston for the automatic transmission for automobiles according to the first aspect of the present invention has the above-mentioned structure, and the piston can be accurately integrally molded from a single plate, resulting in high productivity. Further, one side wall portion 21 of the outer seal ring groove is folded in the inner diameter direction from the outer peripheral edge 41 of the pressure receiving wall portion 4 through the bent portion, and from the inner peripheral edge 42 of the pressure receiving wall portion 4 through the bent portion. By having one side wall portion 31 of the inner seal ring groove folded over in the outer radial direction, a rib effect is generated and the rigidity of the piston is increased, so that tilting and twisting of the piston is reduced, and the seal ring is Since the sealing performance can be maintained and the friction material can be pressed evenly, it is also possible to prevent seizure due to contact with one piece of the friction material.

Further, since the method for manufacturing a sheet metal annular piston for an automatic transmission for an automobile, which is the second invention of the present invention, is mainly constituted by the above-mentioned pressing process, the annular sheet metal piston for an automatic transmission for an automobile is made into one sheet. It can be integrally molded accurately and easily due to the shape, and productivity can be significantly improved.

In particular, the notches 71 and 9 are formed around the circumferential wall surface of the squeezed cylindrical portions 55 and 86, that is, the bottom wall of the seal ring groove, using the notch punch 7, and the press dies 64 and 68 are used to form the notches 71 and 9 at predetermined positions on the circumferential wall surface of the squeezed cylindrical portions 55 and 86, that is, the bottom wall of the seal ring groove. cylindrical part 55,
86 is bent in the radial direction based on the notches 71 and 9 to form the other side wall portions 56 and 87 of the seal ring groove, so that the dimensional accuracy of the bottom wall portions 54 and 88 of the seal ring groove is improved. In other words, the dimensional accuracy of the width of the seal ring groove is improved, and the seal ring groove, which is related to the performance of the piston of an automatic transmission for an automobile, can be accurately integrally molded from a single plate.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a multi-plate clutch portion of an automatic transmission for automobiles, FIG. 2 is a sectional view of a conventional sheet metal piston used in fields other than automatic transmissions for automobiles, and FIG. 3 is a sectional view of a multi-plate clutch portion of an automatic transmission for automobiles. Cross-sectional views of the sheet metal annular piston of the transmission, Figures 4A-H and 5A-G
1 is a manufacturing process diagram of a sheet metal annular piston for an automatic transmission for an automobile according to the present invention. In the figure, 1...A sheet metal annular piston of an automatic transmission for automobiles, 2...Outer seal ring groove, 3...Inner seal ring groove.

Claims (1)

[Claims] 1. An annular pressure receiving wall portion, an outer seal ring groove,
In the sheet metal annular piston for an automatic transmission for an automobile, the piston is provided with an inner seal ring groove, receives hydraulic pressure from the pressure receiving wall portion, and pushes a friction material of the frictional engagement element. One side wall portion of the outer seal ring groove is folded in the inner diameter direction from the periphery via the bent portion, and a bottom wall portion of the outer seal ring groove is formed from the one side wall portion in the axial direction via the bent portion. and the other side wall portion of an outer seal ring groove formed in the outer radial direction from the bottom wall portion via the bent portion, and the inner seal ring groove extends from the inner peripheral edge of the pressure receiving wall portion to the bent portion. one side wall portion of the inner seal ring groove folded over in the outer radial direction through the inner seal ring groove; a bottom wall portion of the inner seal ring groove formed in the axial direction from the one side wall portion via a bent portion; The pressure receiving part wall part, the outer seal ring groove, and the inner seal ring groove are integrally molded. A sheet metal annular piston for an automatic transmission for an automobile, which is characterized by: 2. A process of bending the edges of a circular flat plate in the axial direction using a press to form a cylindrical part that is connected to the circular flat plate part, and folding the flat plate side of the cylindrical part onto the flat plate part to form an outer seal ring. forming one side wall of the groove and at the same time reducing the diameter of the tip end of the cylindrical part to form the bottom wall of the outer seal ring groove; and forming the other side wall of the outer seal ring groove by bending the tip side of the cylindrical portion squeezed by pressing in the radial direction based on the notch. a step of forming a recess projecting to one side by pressing in the center of the circular flat plate, a step of punching out the bottom of the recess, and a step of burring the punched protrusion to form an annular flat plate. and a cylindrical part, the flat plate side of the cylindrical part is folded over the flat plate part to form one side wall part of the inner seal ring groove, and at the same time, the diameter of the tip side of the cylindrical part is a step of forming a bottom wall of the inner seal ring groove; a step of providing a notch at a predetermined position on the inner peripheral wall surface of the squeezed cylindrical portion;
It consists of a step of bending the tip end side of the cylindrical part squeezed by a press in the radial direction with reference to the notch to form the other side wall part of the inner seal ring groove,
A method for manufacturing a sheet metal annular piston for an automatic transmission for automobiles, which comprises a process of molding an inner seal ring groove.