JPH038855B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Field of the Invention The present invention relates to a hydraulic compound extrusion device for cold forging, for example, for drawing a valve tappet that transmits the motion of a cam to a valve or other thin-walled cylinders with a bottom.

(B) Background of the Invention In general, in order to obtain a thin cylindrical product F with a bottom as shown in FIG. 9 in cold forging, first,
As shown in FIG. 4, a substantially cylindrical processed product A is formed by cutting a long material into a predetermined length.

Next, the above-mentioned workpiece A is inserted into the No. 1 die 51 as shown in FIG. 5, and an impact is applied with a No. 1 punch (not shown) from the direction of the arrow in the figure to form the workpiece B. (First step) Next, as shown in FIG. 6, the processed product B is returned and inserted into the No. 2 die 52 with the front and back reversed.
A processed product C is formed by applying impact with a No. 2 punch (not shown) in the direction of the arrow in the figure. (Second step) Next, the above-mentioned processed product C is inserted into the No. 3 die 53 as shown in FIG. A cylindrical workpiece D with a bottom is formed by extrusion. (Third step) Next, the above-mentioned processed product D is inserted into the No. 4 die 54 as shown in FIG. The land 54a performs cylindrical drawing to form a thin-walled cylindrical processed product E with a bottom. (Fourth step) Next, the above-mentioned processed product E is inserted into the No. 5 die 55 as shown in FIG. A product F having a predetermined shape, such as a valve tappet, having a flange at the end is formed. (Fifth Step) In the fourth step of performing the above-mentioned outer diameter drawing, the conventional extrusion device for cold forging, as shown in FIG. Since the device was fixed and pushed forward, the following problems arose.

That is, when extruding the front die from the state shown in FIG. 10 to the state shown in FIG. 11, the tip of the restraining mandrel 56 does not follow the extension of the workpiece E, so the workpiece E passes through the drawing land 54a. At this time, a vacuum gap 58 as shown in FIG. 11 is formed between the inner bottom of the workpiece E and the tip of the restraining mandrel 56.

As a result, deformation stress due to the vacuum suction force of the void 58 acts on the workpiece E, causing a strain sag 59 as shown in FIG. A large ring-shaped depression 60 as shown in the figure occurs, resulting in a serious defect in product dimensions and appearance.

In other words, the processed product E is the drawing land 5 of the die 54.
When passing through 4a, machining is performed with the inner diameter not constrained, so the above-mentioned deformation occurs.

Therefore, in the past, after forming the processed product E,
The cutting process, which is different from the forging process, was used to avoid the above-mentioned defects, which not only increases the manufacturing process of the product, but also causes problems such as poor productivity and high cost of the product itself. had.

(c) Purpose of the Invention This invention provides a hydraulic composite extrusion for cold forging that does not cause distortion or dents on the inner and outer diameter parts of the product, unlike conventional products, by using a unique structure of the mandrel and punch. The purpose is to provide equipment.

(D) Summary of the Invention This invention comprises a cylinder fixed to a punch case, a ring-shaped first piston slidably disposed within the cylinder, and a ring-shaped first piston slidably disposed within the first piston. a second piston; a mandrel disposed at the tip of the second piston and interlocking with the piston; and a mandrel disposed slidably on the outer periphery of the mandrel;
A sleeve-shaped punch that interlocks with the first piston is provided, and the punch and the mandrel are moved relative to each other using hydraulic oil sealed in a hydraulic chamber between each of the pistons and the cylinder, and the tip of the punch is adjusted during forging. The present invention is characterized by a hydraulic compound extrusion device for cold forging configured to constantly press the open end of the product and the tip of the mandrel against the inner bottom of the product.

(E) Effects of the Invention According to this invention, when the extrusion device applies an impact to the product inserted into the die, the reaction force acting on the sleeve-shaped punch causes the first piston to move back through the punch. The second piston can be moved forward using the hydraulic oil sealed in the hydraulic chamber, and the mandrel can be made to follow the elongation of the product.
External diameter drawing can be performed with the mandrel tip always in complete contact with the inner bottom of the product.

As a result, there is no vacuum-like gap created between the inner bottom of the product and the tip of the mandrel, which is the case in the past, and therefore no distortion or dents occur on the inner and outer diameters of the product. There is.

Therefore, compared to conventional devices, the manufacturing process of the product can be reduced, productivity is good, and the cost of the product itself can be reduced.

In addition, since the above-mentioned hydraulic oil is sealed in the hydraulic chamber, internal piping and external piping for double-acting control of each of the first and second pistons are not required, and the device can be simplified. .

(F) Embodiment of the Invention An embodiment of the invention will be described in detail below based on the drawings.

The drawing shows the hydraulic composite extrusion equipment for cold forging,
In FIG. 1, a processed product D is inserted into a predetermined portion of a No. 4 die 2 provided with a drawing land 1.

This processed product D is a cylindrical processed product with a bottom after the third step already explained in FIG.

The structure of the No. 4 punch side that performs the outer diameter drawing of the above-mentioned workpiece D is as described below.

That is, a cylinder 5 is fitted and fixed to the inner periphery 4 of the base of the punch case 3, and a ring-shaped first piston 6 is slidably disposed within the cylinder 5. A cylindrical second piston 7 is slidably disposed therein, and a hydraulic chamber 8 between each of these pistons 6, 7 and the cylinder 5 is filled with hydraulic oil.

Further, a ring-shaped punch holder 9 is disposed in front of the inner periphery 4 of the base of the punch case 3, and a mandrel 11 that is interlocked with the second piston 7 is slid into the guide hole 10 of the punch holder 9. The rear end of the mandrel 11 is brought into contact with the front end surface of the second piston 7.

The above-mentioned mandrel 11 is a rod-shaped member whose outer diameter corresponds to the inner diameter of the above-mentioned workpiece D, and a drain 12 is formed in the axial center of the mandrel 11 to release oil from the workpiece D side. are doing.

Furthermore, a plurality of pin holes 13... are formed in the punch holder 9, and each of the plurality of pin holes 13...
A pin 14 that interlocks with the first piston 6 is slidably inserted into.

A plate 15 is slidably fitted loosely on the outer periphery of the mandrel 11 in front of the plurality of pins 14, and this plate 15 is attached to the punch case 3.
It is disposed within a clearance 17 between the base and the tip 16 of.

Further, on the outer periphery of the above-mentioned mandrel 11, a sleeve-shaped punch 1 is disposed in front of the plate 15.
8 is slidably disposed, and the outer periphery of this punch 18 is supported by a guide hole 19 formed at the center of the tip 16 in the punch case 3, and this punch 18 is supported by the aforementioned puto 15 and a plurality of It is linked to the first piston 6 via pins 14.

Then, the punch 18 and the mandrel 11 are moved relative to each other via the hydraulic oil sealed in the hydraulic chamber 8 during forging, so that the tip of the punch 18 is placed at the open end of the workpiece D, and the tip of the mandrel 11 is placed at the open end of the workpiece D. It is configured to be in constant pressure contact with the inner bottom of the.

By the way, a knock-out plate 22, so-called PKO plate, is slidably disposed in the guide hole 21 of the punch plate 20 fixed to the back surface of the cylinder 5, while a long knock-out plate 22 is provided in the pin hole 23 bored in the punch case 3. A long knockout pin 24, a so-called PKO pin, is fitted loosely, and at the end of cold forging (fourth step processing) using this device, the knockout pin 24 is projected forward by the forward movement of the knockout plate 22 described above. By protruding the plate 15 and punch 18 in the same direction, the mandrel 1
It is configured to automatically remove the processed product E (see Fig. 3) fitted to the outer periphery of the first tip.

The illustrated embodiment is configured as described above,
The action will be explained below.

Now, the bottomed cylindrical processed product D shown in Fig. 1 is
When performing cold forging, that is, outer diameter drawing, on the thin-walled cylindrical workpiece E shown in FIG. 2, when an impulse force is applied in the direction of the arrow a in FIG. The reaction force acting on
The first piston 6 is moved back from the state shown in FIG. 1 through the punch 18, plate 15, pin 14, etc. as shown in FIG. 2.

For this reason, with respect to the inner bottom of the workpiece E which is squeezed into a cylindrical shape by the squeezing land 1 and pushed forward, it is moved forward in conjunction with the second piston 7 that moves forward via the hydraulic oil sealed in the hydraulic chamber 8. The tip of mandrel 11 that protrudes to
1 to the same processed product E according to the length of the processed product E.
The above-mentioned outer diameter reduction can be performed while completely adhering to the inner bottom of the tube.

As a result, there is no vacuum-like gap created between the inner bottom of the workpiece E and the tip of the mandrel 11 as in the conventional example shown in FIG. A processed product E with good product dimensions and appearance can be obtained without any distortion or dents occurring in the part.

Therefore, compared to conventional equipment, it is possible to reduce the manufacturing process of the product, and the productivity is good and can keep up with operation at, for example, 150 SPM per minute, and the cost of the product itself can be reduced. It has the effect of

Furthermore, since the above-mentioned hydraulic oil is sealed in the hydraulic chamber 8, special internal piping and external piping for double-acting control of the first piston 6 and the second piston 7 are not required, which simplifies the device. It also has the effect of being able to be made smaller and more compact.

Note that from the state shown in Fig. 2, the ejector knockout pin on the die 2 side is protruded to the right, and
When the entire extrusion device is moved backward, the knockout plate 22 is moved forward as shown in FIG. , the processed product E fitted around the outer periphery of the tip of the mandrel 11 is automatically removed from the tip of the mandrel 11.

Regarding the correspondence between the structure of this invention and the above-mentioned embodiments, the product of this invention corresponds to the processed products D and E of the embodiments, but this invention is limited only to the structure of the above-mentioned embodiments. isn't it.

In other words, it is of course applicable to cold forging of thin-walled cylindrical shapes with bottoms other than the valve tappets exemplified in the above-mentioned embodiments, and the above-mentioned hydraulic oil may include grease or the like in addition to cylinder oil. It goes without saying that hydraulic oil may also be used.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention; FIG. 1 is a sectional view of a hydraulic compound extrusion device for cold forging, FIG. 2 is a sectional view showing the outer diameter drawing action of the device, and FIG. 3 is a cross-sectional view of the device. 4 is a side view of the material for cold forging, FIG. 5 is a sectional view showing the first step of cold forging, and FIG. 6 is a sectional view showing the second step of cold forging. 7 is a cross-sectional view showing the third step of cold forging, FIG. 8 is a cross-sectional view showing the fourth step of cold forging, and FIG. 9 is a cross-sectional view showing the fifth step of cold forging. 10 is a schematic diagram showing a conventional extrusion device,
FIG. 11 is a schematic diagram showing the outer diameter throttling effect of the conventional device. 3...Punch case, 5...Cylinder, 6...
1st piston, 7...2nd piston, 8...hydraulic chamber, 11...mandrel, 18...punch, D,
E...Processed product.

Claims (1)

[Scope of Claims] 1. A hydraulic compound extrusion device for cold casting that performs drawing of a thin-walled cylinder with a bottom, comprising: a cylinder fixed to a punch case; and a first ring-shaped extruder slidably disposed within the cylinder. a piston, and a second piston slidably disposed within the first piston.
A piston, a mandrel disposed at the tip of the second piston and interlocked with the piston, and a sleeve-shaped punch slidably disposed on the outer periphery of the mandrel and interlocked with the first piston, each of the above. Hydraulic oil sealed in the hydraulic chamber between the piston and cylinder moves the punch and mandrel relative to each other, so that during forging, the tip of the punch is always at the open end of the product and the tip of the mandrel is always at the inner bottom of the product. A hydraulic compound extrusion device for cold forging designed for pressure welding.