JPH035025A - Manufacture of cylindrical metal tool having stepped part - Google Patents

Abstract

PURPOSE:To save machining by cutting, etc., and to improve manufacturing efficiency of a cylindrical metal tool having stepped part by pushing a forming roller against outer circumferential face of a metal pipe and relatively rolling along the outer circumferential face of the metal pipe while applying pressurizing force toward inner direction to shrink the diameter of a part of the pipe. CONSTITUTION:The forming roller 18 having small diameter part forming face 14 and stepped part forming face 16 is brought into contact with the outer circumferential face at the end part of the metal pipe 11, and the outer end part of the metal pipe is fixed. Successively, while applying the pressurizing force toward inner directionto the outer circumferential face of the metal pipe 11 with the forming roller 18 the forming roller 18 is rolled along the outer circumferntial face of the pipe to execute plastic deformation to the end part of the metal pipe 11 toward diameter shrinkage direction in order. By this method, the small diameter part 20 is formed at one end side of the metal pipe 11, and large diameter part 22 at the other end side and the stepped part 24 at boundary part between both parts are formed.

Description

[Detailed description of the invention] (Industrial application field) The present invention relates to a method of manufacturing a stepped cylindrical metal fitting.

(Prior Art) As shown in FIG. 3(A), one type of vibration-proof rubber is a cylindrical inner metal fitting 100, a similarly cylindrical outer metal fitting 102, and a rubber material arranged between them. There is a bush-shaped type consisting of a rubber elastic body 104.

This anti-vibration rubber bushing 106 has a small diameter part 122 and a large diameter part 108 formed in an outer cylindrical metal fitting 102, and as shown in FIG. The device is press-fitted into the device, and is attached and held at a predetermined location in a vehicle, etc.

Therefore, when manufacturing the outer cylindrical metal fitting 102 of the anti-vibration rubber bushing 106, the small diameter portion 122 and the large diameter portion 102 are
8 needs to be processed and formed, and the method shown in FIG. 4 has conventionally been used as the processing method. In the figure 1
12 is a long metal tube such as a drawn steel tube, which is first cut into a predetermined length. Then, cut the metal pipe 112 (
The other mold 1 with the corresponding pin 119 is set in the retaining hole 118 of the mold 114 as shown in B).
16 (see (C)), and the metal pipe 112
is pressed in the axial direction to form the large diameter portion 108 and the small diameter portion 122 together with the flange 120 at the end of the tube at once. Thereafter, the end of the tube opposite to the flange 120 is finished by cutting and chamfering.

(Problem to be solved by the invention) By the way, in such a processing method using a press, the mold 1
Since it is necessary to provide a predetermined amount of clearance between the holding holes 11g of 14 and the outer circumferential surface of the metal pipe 112, and between the pin 119 of the mold 116 and the inner circumferential surface of the metal pipe 112, when pressing as shown in FIG. The portion sandwiched between the pin 119 and the inner wall surface of the holding hole 118 (the small diameter portion 122 of the outer cylinder fitting 102) will be deformed. For this reason, after the press working, it is necessary to cut the outer circumferential surface and inner circumferential surface of the small diameter portion 122 to obtain the dimensions.

However, when such machining is applied, not only is there a lot of loss, but the machining also takes a lot of effort and time, which reduces the production efficiency of the product.
It also increases product cost.

Further, problems arise such as cutting oil, smoke, or cutting debris scattering during cutting, deteriorating the working environment.

(Means for Solving the Problems) The present invention has been made to solve the above problems, and its gist is that the present invention has a large diameter portion and a small diameter portion, and the boundary portion thereof has a stepped shape. A method of manufacturing a cylindrical fitting from a metal pipe of a predetermined length, the method comprising: attaching the outer peripheral surface of a forming roller rotatable around its own axis parallel to the axis of the metal pipe to the outer peripheral surface of the metal pipe; the metal pipe, and in this state, the forming roller relatively rolls along the outer circumferential surface of the metal pipe while applying a radially inward pressing force to the metal pipe, thereby forming the metal pipe. The small-diameter portion is formed by plastically deforming the contacted portion in a diameter-reducing direction.

(Operation and Effects of the Invention) As described above, the method of the present invention presses the forming roller against the outer circumferential surface of the metal pipe, applies a radially inward pressing force to the pipe to be bent, and presses the forming roller against the outer peripheral surface of the metal pipe. By rolling relatively along the outer circumferential surface, a part of the pipe is plastically deformed in the diametrical direction to form a small diameter portion.

That is, in the present invention, no pressing force is applied to the metal pipe in the axial direction. Therefore, there is no problem that the pipe is deformed by the pressure applied in the axial direction, and therefore, there is no need to perform machining such as cutting for dimensioning after the forming process. This saves nine hours of labor for manufacturing metal fittings, and also eliminates material loss.

Furthermore, the present invention has the advantage that there is no need to use a forming die, and there is no problem of deteriorating the working environment due to scattering of cutting waste, cutting oil, etc. In addition, since the process is based on the transfer of forming rollers, There are various advantages such as low processing noise and easy setup changes.

(Example) In FIG. 1, lO is a drawn steel pipe, which is first cut into predetermined lengths to prepare a metal pipe 11. next(
As shown in B), a forming roller 18 having a rotation axis 12, a small diameter portion forming surface 14 and a stepped portion forming surface 16,
Contact the outer peripheral surface of the metal pipe ll at the end thereof,
Then, with the other end of the metal pipe I fixed, the forming rollers 18 are transferred along the outer circumferential surface of the pipe while applying an inward pressing force to the outer circumferential surface of the metal pipe IT. , the ends of the metal pipe 11 are sequentially plastically deformed in the diametrical direction. As a result, a small diameter portion 20 is formed at one end of the metal pipe 11, a relatively large diameter portion 22 is formed at the other end of the metal pipe 11, and a stepped portion 24 is formed at the boundary between the two. Since the large diameter portion 22 is not subjected to any pressure or deformation during this processing, its outer diameter and inner diameter are the same as the outer diameter and inner diameter of the original metal pipe 11, respectively.

On the other hand, the small diameter portion 20 can be finished to a desired outer diameter and inner diameter by appropriately setting processing conditions using the forming roller 18.

Next, as shown in (G), a forming roller 28 having an axis 12 and a flange forming surface 26 is brought into contact with the inner circumferential surface of the end of the large diameter portion 22, and rotates and revolves (transfers).
while pushing in the axial direction.

Then, the end portion of the large diameter @22 is pushed outward and formed into a flange 30 in the shape of the final product along the flange forming surface 26 of the forming roller 28.

After forming the flange 30 in this way, (D)
As shown in FIG.
The small diameter part 2 is rotated and rolled while pinching the end of the pipe.
Chamfer the tube end of o. At this time, the length of the small diameter portion 20 in the axial direction becomes somewhat longer. Therefore, in the same processing,
It is necessary to ensure that the length after processing matches the length of the final product shape.

As a result of the above, the flange 30. The machining of the outer cylindrical fitting 38 having the large diameter portion 229, the stepped portion 24, and the small diameter portion 20 is completed.

As described above, the method of this example forms the small diameter portion 20 and the large diameter portion 22 by partially inwardly plastically deforming the raw metal pipe 11 while rotating the forming roller 18. Therefore, unlike the conventional method of forming large and small diameter parts by applying pressure in the axial direction of the raw metal pipe using a forming die, machining such as cutting to obtain dimensions is performed after forming. This simplifies the manufacturing process of the outer cylindrical fitting 38, saves 9 hours of labor, eliminates material loss, lowers processing costs, improves the working environment, and provides the various advantages mentioned above. arise.

In this example, the diameter reduction process is first performed using the forming roller 18 to form the small diameter portion 20. After forming the large diameter portion 22, the forming roller 2
However, as shown in Fig. 2, the order of these processes is reversed and the flange processing is performed first (Fig. 2 (C)).
Then, a part of the metal pipe 11 is reduced in diameter (FIG. 2(D)) to form a small diameter portion 20. A large diameter portion 22 may also be formed. If necessary, as shown in (B), the flange 3
The inner peripheral edge of the pipe end of the metal pipe 11, which is the outer peripheral edge of the metal pipe 11, may be chamfered. This chamfering process can be performed using a set of a forming roller 34 equipped with a forming surface 32 for chamfering and a forming roller 36 having a straight forming surface, as in the process shown in FIG. 1 (D) above. It is.

Although the embodiments of the present invention have been described in detail above, the present invention can be implemented in other embodiments.

For example, in the above example, when forming the small diameter portion 20, the forming roller 18 is arranged only on the outer peripheral surface side of the metal pipe 11,
Although the metal pipe 11 is partially reduced in diameter only by the forming roller 18, forming rollers are also arranged on the inner peripheral surface of the metal pipe 11 to receive the load.
The metal pipe 11 may be sandwiched between the rollers on both the outer and inner surfaces of the rollers to plastically deform it.

The present invention can also be applied to stepped cylindrical metal fittings without flanges as in the above example, to metal fittings other than anti-vibration rubber products, and even to the production of metal fittings made of metal materials other than steel. It is possible, and by rotating the metal pipe side instead of rotating the forming roller side as in the above example, or by rotating either side of the forming roller or the metal pipe depending on the case. The present invention can be implemented with various modifications based on the knowledge of those skilled in the art without departing from the spirit thereof, such as the possibility of plastically deforming the metal pipe.

[Brief explanation of drawings]

FIG. 1 is a process explanatory diagram of a method for manufacturing a stepped cylindrical metal fitting according to an embodiment of the present invention, and FIG. 2 is an explanatory diagram of a method according to another embodiment of the present invention. FIG. 3(A) is a sectional view of a vibration-proof rubber bushing, which is an example of an object to which the present invention is applied;
) is an explanatory diagram of how to press-fit and attach the same anti-vibration rubber bushing,
FIG. 4 is an explanatory diagram of a conventional manufacturing method of the same anti-vibration rubber bushing. 11: Metal pipe 12: Axis 18, 28, 34, 36: Forming roller 20: Small diameter part 22 Two large diameter parts 24: Stepped part 30: Flange 38: Outer cylinder metal fitting

Claims (1)

[Claims] A method for manufacturing a cylindrical metal fitting having a large diameter portion and a small diameter portion, the boundary portion of which forms a stepped shape, from a metal pipe of a predetermined length, the method comprising: an axial center of the metal pipe; The outer circumferential surface of a forming roller that is rotatable around its own axis that is parallel to the surface of the metal pipe is brought into contact with the outer circumferential surface of the metal pipe, and in this state, a radially inward pressing force is applied to the metal pipe by the forming roller. The small diameter portion is formed by relatively rolling the forming roller along the outer circumferential surface of the metal pipe to plastically deform the contacted portion of the metal pipe in a diametrical direction. A method for manufacturing a stepped cylindrical fitting.