JP2584046B2 - Molding method of component having stepped shaft portion and cup-shaped portion - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for simultaneously forming a shaft and a cup-shaped part of a component having a shaft and a cup-shaped part such as an outer ring of a constant velocity joint.

(Prior Art) In recent years, components of various shapes have been obtained by cold forging in which a material is plastically deformed at a temperature lower than a transformation point.

If the material is not forged and formed without forming a lubricating film, seizure occurs. For this reason, in the past, a chemical conversion coating was formed on the material surface by bond processing,
In general, a method of spraying lubricating oil onto the material and the mold is used. However, in the former case, the film almost disappears by one forging, and the material once molded is continuously used by using another mold. In each case of forming, a chemical conversion film must be formed on the material film, and in the latter case, there is a problem that the working environment is deteriorated and a lubricating film is difficult to be formed uniformly.

Therefore, as disclosed in Japanese Patent Application Laid-Open No. 59-150639, a method of forging by supplying a lubricating oil into the cavity during molding is conceivable.

(Problems to be Solved by the Invention) When forging is performed in a state where the above-described lubricating oil is filled in the cavity, the timing of supplying the lubricating oil is important depending on the shape of the part to be molded.

That is, when molding both the stepped shaft portion and the cup-shaped portion at the same time, if the cavity is completely filled with the lubricating oil in advance, even if the material is charged into the cavity, the material is quickly moved to the bottom portion in the cavity. Therefore, the upper surface of the material and the punch are in direct contact with each other without lubricating oil and seizure easily occurs. On the other hand, if the lubricant is supplied after setting the material in the cavity,
Although the upper surface of the material is covered with the lubricating oil, the lubricating oil does not sufficiently reach the lower portion of the material, and when forming the stepped shaft portion, galling or the like occurs.

(Means for Solving the Problems) In order to solve the above problems, the present invention provides a method in which a material is charged into a cavity in a state where lubricating oil is filled up to a predetermined height of a small diameter hole of a cavity for molding a stepped shaft portion of a component, Next, after supplying lubricating oil toward the upper surface of the material in the cavity, the material was extruded by a punch.

(Operation) The material is put into the cavity with lubricating oil filled up to a predetermined height of the small diameter hole at the bottom of the cavity, and then the lubricating oil is supplied to the remaining portion of the cavity to quickly and completely lubricate the entire surface of the material. Can be covered with.

(Example) Hereinafter, an example of the present invention will be described with reference to the accompanying drawings.

FIG. 1 is a cross-sectional view showing a state before a material is put into an extrusion molding apparatus for carrying out the method of the present invention, FIG. 2 is a cross-sectional view showing a state after a material is put into the molding apparatus, and FIG. FIG. 4 (A) is a cross-sectional view showing a state during and after completion of molding.
(B) and (C) are parts A in FIGS. 2 and 3, respectively.
It is an enlarged view of the B section and the C section.

First, the configuration of the molding apparatus will be described. The molding apparatus includes a mold 1 and a punch 2 in which a plurality of divided molds are stacked, and the mold 1 has a cavity 3 opening upward.

The upper part of the cavity 3 is a large-diameter hole 3a for forming a cup-shaped part, and the lower part is a small-diameter hole 3b for forming a stepped shaft part.
An aperture step 4 is provided in the middle of the small diameter hole 3b. The supply path 5 for the lubricating oil O is provided on the side surface of the large-diameter hole 3a.
The discharge pin 6 faces the small-diameter hole 3b from below, a discharge path 7 for the lubricating oil O is opened around the discharge pin 6, and the lubricating oil tank 8, the supply path 5 and the discharge path 7 are further connected. In the connecting pipe, a fixed amount supply device 9 and a fixed amount discharge device 10 are provided.
Is provided.

The means for forming a component having a stepped shaft portion and a cup-shaped portion, such as a constant velocity joint outer ring, using the above-described forming device will be described below.

First, before the raw material W is charged into the cavity 3, the lubricating oil O is left to a predetermined height position in the small diameter hole 3b of the cavity 3 as shown in FIG. Here, the liquid level of the lubricating oil O is adjusted by the constant-rate discharge device 10. As the lubricating oil O, a lubricating oil or the like which forms a lubricating film on the surface of the material W by heat is used. The level of the lubricating oil O may be controlled by the diameter of the discharge path 7 without using the constant-rate discharge device 10. The material W is a preformed material having a large diameter head W1 and a shaft portion W2, and specifically, a rod-shaped material (a billet)
And the temperature of the raw material W at the time of being charged into the cavity 3 is set to about 150 to 400 ° C.

Next, as shown in FIG. 2, before the lower surface of the large-diameter head W1 of the raw material W hits the bottom of the large-diameter hole 3a of the cavity 3, new lubricating oil O is introduced into the cavity 3 from the lubricating oil supply path 5 and the liquid level thereof is increased. The material W is supplied to a position higher than the upper surface. At the same time, the punch 2 is lowered.

At the time when the material W is charged into the cavity 3, the fourth
As shown in FIG. A, the lubricating oil O in the small-diameter hole 3b is
The liquid level rises due to the entry of W2, and the space between the shaft portion W2 and the small-diameter hole 3b is filled with the lubricating oil O. Also, the large diameter head W1 of the material W
Before molding, there is a gap between the large diameter hole 3a of the cavity 3 and the lubricating oil O supplied from above quickly spills over to the side surface and the lower surface of the large diameter head W1, and the entire surface of the material W Is covered with the lubricating oil O.

Then, the punch 2 is lowered, and as shown in the left part of FIG. 3 and FIG. 4 (B), the shaft is extruded first, and then the large-diameter head W1 is extruded backward to form the cup-shaped part W3. Go on.

Further, in the present embodiment, since the lubricating oil is also filled on the small-diameter shaft portion W4 formed by the front extrusion, the lubricating oil effect can be enhanced by applying a back pressure to the lubricating oil. This differs from conventional hydrostatic extrusion and containment.

Thereafter, the punch 2 is further lowered to complete the formation of the cup-shaped portion W3 and the small-diameter stepped shaft portion W4 as shown in the right part of FIG. 3 and FIG. 4C.

(Effects of the Invention) As described above, according to the present invention, when forging the stepped shaft portion and the cup-shaped portion at the same time using the lubricating oil, the lubricating oil is previously set in the small diameter hole of the cavity for forming the stepped shaft portion. The lubricating oil is supplied after charging the material into the large-diameter hole of the cavity for forming the cup-shaped part, so that the material can be forged with the entire surface covered with the lubricating oil. There is no sticking.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a state before a material is charged in an extrusion molding apparatus for carrying out the method of the present invention, FIG. 2 is a cross-sectional view showing a state after a material is charged in the molding apparatus, and FIG. FIG. 4 (A) is a cross-sectional view showing a state during and after completion of molding.
(B) and (C) are parts A in FIGS. 2 and 3, respectively.
It is an enlarged view of the B section and the C section. In the drawings, 1 is a mold, 2 is a punch, 3 is a cavity, 3a
Is the large hole in the cavity, 3b is the small hole in the cavity, 4 is the step, W is the material, W1 is the large diameter head of the material, W2 is the shaft of the material, W3 is the cup-shaped portion, and W4 is the step shaft. It is.

 ──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Haruo Meguro 1-10-1, Shinsayama, Sayama City, Saitama Prefecture Honda Engineering Co., Ltd. (56) References JP-A-2-197342 (JP, A) JP-A-Hei 1-38124 (JP, A) JP-A-1-168684 (JP, A) JP-A-2-93036 (JP, A)

Claims (1)

(57) [Claims] 1. A lubricating oil is filled up to a predetermined height of a small-diameter hole of a cavity in which an upper portion has a large-diameter hole and a lower portion has a small-diameter hole connected to the large-diameter hole. The lubricating oil is injected toward the upper end surface of the material, and the surface of the material is covered with the lubricating oil. Thereafter, the punch is inserted into the cavity from above, and the large diameter A method of forming a part having a stepped shaft portion and a cup-shaped portion, wherein the head portion is formed into a cup-shaped portion by backward extrusion and the shaft portion is formed into a stepped shaft portion by forward extrusion.