JPS6027436A - Formation of piston ring groove of seat pipe for shock absorber - Google Patents

Abstract

PURPOSE:To prevent cracking, cutting, etc. arising in the groove on the body side of a seat pipe by pressing a steady rest provided with an axially slidable rotating member in the joint part between the piston part and body of said seat pipe. CONSTITUTION:The screw part 2 side of a seat pipe 1 is grasped and supported by a chuck 7 and a steady rest 9 is pressed to the joint part between the piston part 4 and the pipe 1 body part and while the pipe 1 is rotated, a grooving roller 10 is pressed to the sliding surface 5 of the part 4 to form a piston ring groove 6. The steady rest 9 provided with a rotating member 8 such as, for example, a bearing, which can slide axially is pressed to the joint part between the piston part 4 and the pipe 1 body in this stage to support said part.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for forming a piston ring groove for a shock absorber, which can prevent damage to the piston ring groove.

What about sheet pipes in buffers? A piston part that slides on the inner periphery of the fork/eve that can fit and slide on the inner periphery of the tom case is provided on the open end side, and a threaded part is provided at the other end on the bottom of the tom case. It is used coaxially fixed by a bolt.

Seat pipes are usually made by drawing a tube material with an outer diameter corresponding to the outer diameter of the piston part, so that the oil lock piece of the fork arm slides into sliding contact with the ide body and the threaded part with a smaller outer diameter. The product was manufactured by polishing the sliding surface of the piston part, forming a gist ring groove, threading the inner periphery of the threaded part, and drilling an oil hole. Therefore, to form a ring groove on the sliding surface of the piston part, the threaded part side is clamped and supported by a chuck, and a steady rest is brought into contact with the joint part of the piston part and the pipe body to hold the seat pipe. This was done by pressing a groove forming roller against the sliding surface while rotating.

However, when forming a piston ring groove using this method, the axial width of the piston part is short, and the pipe body side of the groove is held down by a steady rest, so when the groove is formed, the piston ring groove stretches toward the body side. There was a risk that the parts could not be absorbed and cracks could occur at the locations shown in the attached drawings (marked with shu), causing them to be cut and damaged.

As a result of repeated research to solve this problem, the inventor of the present invention found that while the end surface side of the piston part is free, the threaded part side of the piston main body side is clamped by a chuck. Since the joint between the piston part and the pipe body is in contact with the steady rest, the end surface side of the piston part freely moves in the axial direction of the sheet pipe (hereinafter referred to as , referred to as the axial direction), and the force from machining can be released to the end face side. However, the t4 eve main body side is prevented from elongating in the axial direction, and the force cannot be released; Recognizing that damage is concentrated in the areas shown in A), the steady rest is provided with a rotating member such as a bearing that can slide in the axial direction, thereby allowing it to expand in one direction. The present invention was created based on the recognition that the object could be achieved by the following.

Next, embodiments of the present invention will be described based on the accompanying drawings. The drawing is a schematic side cross-sectional view showing one embodiment of the method of the present invention.

Using a steel pipe with an outside diameter of 1B + 1111ψ and a length of 228, the pipe body (1) with an outside diameter of 181111 + 1φ and a length of 197B and the threaded part (2) with an outside diameter of 13.5 amψ and a length of 19 fl are drawn using a drawing method. formed by, diameter 8wrsψ
The oil hole (3) is machined, deburred, and a female thread is cut on the inner periphery of the threaded part (2). Piston part (
The sliding surface (5) of 4) was polished to form a piston ring groove (6) with a width of 4 wn and a depth of 1.75 m.

Thus, the piston ring groove (6) was formed as follows. That is, the outer periphery of the threaded part (2) is clamped and supported by the chuck (7), and a bearing, for example, that can slide in the axial direction is attached to the joint between the piston part (4) and the pipe body (1). While the sheet pipe is rotated by a rotation mechanism (not shown) attached to the chuck (7), the groove forming roller OG is the piston part (4
) by pressing against the sliding surface (5). The piston ring groove (6) is formed as the groove forming roller OI is pressed, but the force applied at this time is the force in the direction of the end face of the piston part (4), while the end face side is free. Therefore, when a force is applied, it can be released by freely extending in the axial direction, and a force in the side direction of the blade main body (1) can be released by freely extending towards the threaded part (2). In other words, when a force that extends in the axial direction acts on the Nonoide main body (1) side, it acts to push the rotating member (8), but since the rotating member (8) can slide in the axial direction, 7JD
It slides in the direction of the threaded part (2) without suppressing the breaking force and releases it, and the main body (1) itself extends in the direction of the threaded part (2) and releases the force applied in this direction, completely preventing damage. obtain.

No damage to the piston ring groove was observed in the sheet pide product manufactured by this method.

In the present invention, a piston ring groove is formed so that a steady rest equipped with a rotating member that can slide in the axial direction is brought into contact with the joint between the piston part of the piston and the piston main body. When forming the piston ring groove, it was possible to prevent damage such as cracks and cuts occurring on the ie ide main body side of the groove, and an excellent effect is recognized.

[Brief explanation of the drawing]

The drawing is a schematic side cross-sectional view illustrating an embodiment of the present invention.

Claims (1)

[Claims] 1) Hold and support the threaded part of the seat pipe with a chuck. A steady rest is in contact with the joint between the piston part and the IP Eve main body, and while the seat pipe is rotating, a roller for forming grooves on the sliding surface of the piston part is applied. In the method of forming piston ring grooves by pressing, a piston ring groove is formed by pressing a steady rest with a rotating member that can slide in the axial direction of the seat pipe at the joint between the piston part and the sleeve body. 1. A method for forming a piston ring groove in a seat pipe for a shock absorber.