JPS628913Y2 - - Google Patents

Description

[Detailed Description of the Invention] The disclosed technology belongs to a technical field in which the applied pressure of a forging device used for forming parts is adjusted by an upper die and a lower die.

Therefore, in this invention, a workpiece is set in a lower die mounted on a mandrel of a bolster, and then an upper die suspended from a ram is lowered relative to the workpiece to process and form the ram. This invention relates to a forging die structure of a press machine, and in particular, at least one of the upper die and the lower die has a thin wall part for adjusting applied pressure in the middle of the mold, and the applied pressure is adjusted to the thin wall part during processing and forming of the workpiece. This invention relates to a forging die structure for a press device that transmits adjustment by.

As is well known, in order to easily temporarily assemble a workpiece mounted on a shaft such as a gear, a latch protrusion is formed on the inner diameter of the workpiece before assembly, and the workpiece is attached to the shaft. It is designed to be press-fitted into the

The seed projection is generally formed by cutting or cold forging.

However, while the former method has the advantage of guaranteed dimensional accuracy, it has the disadvantages of a large number of machining steps, a low yield rate, and poor productivity.

On the other hand, in the latter case, the number of processes for forming protrusions on the workpiece by applying pressure is reduced compared to the above-mentioned cutting process, but the thickness of the protrusions is set to minute dimensions, for example, 1 mm or less. The problem was that it was difficult to judge based on the capacity of the press equipment.

To deal with this, conventionally, as shown in FIG. 1, the tip 3' of the punch 3 serving as an upper die, which is vertically installed on the ram 2 of the press device 1, is adjusted so that θ ₁ is 60 degrees as shown in FIG.
The gear shown in FIG. 3a is mounted on a mandrel 5 erected on a bolster 4, with θ ₂ set at 30 degrees, and set in advance on an ejector sleeve 7 as a lower die that forms a forging die 6 together with the punch 3. The tip 3' of the punch 3 is stamped by lowering the ram 2 onto a ring-shaped work 8 such as the above, and the vicinity of the inner diameter 8' of the work 8 is protruded inward as shown in Fig. 3b. , a mode in which the projections 9 are formed by so-called caulking has been adopted.

Therefore, in the above embodiment, it is possible to mold the thickness of the protrusion 9 to a very small size, but if the thickness of the workpiece 8 changes from lot to lot, the descending stroke of the ram 2 also changes. Naturally, this changes, so the stamping pressure on the workpiece 8 is not constant.
As a result, the inwardly protruding thickness of the protrusion 9 is not determined,
There was a problem that the inner diameter dimensional accuracy error of the protrusion 9 became large.

The purpose of this invention is to solve the technical problem of workpiece machining by cold forging using a press machine based on the above-mentioned conventional technology, and to form a thin section for adjusting applied pressure on at least one of the upper die and the lower die. The above-mentioned problem is solved by absorbing the stamp pressure difference caused by the change in the thickness of the workpiece in the thin section, and the above-mentioned upper mold,
Although it has a simple structure by improving only the lower die, it is an excellent forging die for press equipment that is useful in the field of cold working equipment used in the mechanical parts manufacturing industry, where the pressure applied to the workpiece is uniquely achieved. It is intended to provide structure.

In order to solve the above-mentioned problems, the structure of this invention in accordance with the above-mentioned purpose is to set a workpiece on a lower mold that is mounted on a mandrel that is set upright on the bolster of a press machine, and then lower the ram. An upper die suspended vertically on the ram applies pressure to the workpiece to perform a prescribed forming process, and during this time, the thin wall portion of at least one of the upper die and the lower die changes depending on the thickness of the workpiece. The gist is that the workpiece is elastically deformed and the pressure applied to the workpiece is maintained and adjusted at a constant pressure state.

Next, one embodiment of this invention will be described below with reference to FIG. 1 and the drawings from FIG. 4 onwards.

To explain the structure of this embodiment, 1' is a press device for cold forging, and a well-known ejector 10 having an ejector pin 11 is inserted into the bolster 4 so as to be able to operate a predetermined stroke. is a hole 12 through which the ejector pin 11 can be inserted.
A base plate 13 having a mandrel 5 is erected and fixed thereto.

An ejector sleeve 14 serving as a lower mold is installed on the base plate 13 so as to be slidably inserted in the mandrel 5 in the axial direction, and has a flange 15 at its base that can engage and come into contact with the ejector pin 11. As shown in FIG. 4a, a thin walled portion 16 is formed in the middle, and the tip 17 faces the work setting cavity 18 of the bolster 4.

On the other hand, a punch 19 as an upper die facing the ejector sleeve 14 is vertically fixed to the upper ram 2 via a plate 20, and a cavity 21 into which the mandrel 5 can be fitted is bored in the middle. It also has a thin walled part 16', and its top end 19' is at an angle of 25 degrees at _θ3 and 30 degrees at _θ4 , as shown in FIG.
It has a 0.5mm radius.

Incidentally, the ejector sleeve 14 and the punch 19 constitute a forging die 6'.

Further, 8 is a ring-shaped workpiece as in FIG. 1, and the mandrel 5 is provided with a stepped portion 5' for forming the protrusion 9' of the workpiece 8.

To explain the operation of the above structure, the embodiment shown in FIG. 4 is a state in which the workpiece 8 is forged, but in the initial position, the ram 2 rises and the punch 19 is moved as shown in FIG. is hanging down normally.

Therefore, in the above initial position, cavity 1
The ring-shaped workpiece 8 is set in a predetermined position in the workpiece 8, and then the ram 2 is lowered and the tip 19' of the punch 19 is applied pressure to the upper surface of the workpiece 8 to punch the upper surface. The upper end of the workpiece 8 is made to protrude inward and abut against the stepped portion 5' of the mandrel 5 to form a protrusion 9.

During this time, if the pressure applied to the workpiece 8 is above a predetermined value, the ejector sleeve 14 and the thin-walled portion 1 of the punch 19 are removed, as shown in FIG.
6 and 16' are elastically deformed to absorb the amount.

Therefore, even if the descending stroke of the ram 2 changes due to the thickness of the workpiece 8 varying from lot to lot, the pressure applied to the workpiece 8 remains constant.

The thin portions 16, 16' shown in FIG. 4 are shown in a deformed form for convenience.

After the specified forging is completed, the ram 2 is returned to its initial position as shown in FIG. 6. Next, the ejector 10 is operated to cause the ejector pin 11 to slide and protrude the ejector sleeve 14, so that the work 8 which has been formed to the specified position is exposed outside the bolster 4 and is removed.

During this time, as a matter of course, pressure is not applied to the workpiece 8, so that the ejector sleeve 14 and the thin-walled portions 16, 1 of the punch 19 are removed.
6' has returned to its shape.

On the other hand, since the tip of the punch 19 is ground to an acute angle as shown in FIG. 5, stamping can be performed only locally, and as a result, the protrusion 9 of the workpiece 8 is easily formed. .

It goes without saying that the embodiment of this invention is not limited to the above-mentioned embodiment. For example, the thin wall portion may be provided in either the ejector sleeve or the punch, or the thin wall portion may be provided in either the ejector sleeve or the punch. Various aspects can be adopted, such as forming the abutting portion for the work protrusion in an uneven shape so that the shape of the protrusion can be varied in various ways.

As mentioned above, according to this invention, in the forging die structure of the press device, at least one of the upper die vertically disposed on the ram of the press device and the lower die shafted on the mandrel erected on the bolster is applied. By having the pressure adjusting thin wall part, the inconsistency in the descending stroke of the ram that occurs due to the difference in plate thickness when forming a protrusion on the workpiece is basically absorbed and adjusted by the thin wall part. Since pressure is uniquely applied to the workpiece, not only can the protrusion be formed with minimal internal diameter dimensional accuracy error, but also the yield rate is high because it is cold forged. , the excellent effects of improved productivity and product stability can be achieved.

Furthermore, since the structure is simple, with only a thin wall portion provided in at least one of the upper and lower dies, it is easy to manufacture, inexpensive, and has excellent maintainability.

On the other hand, since the applied pressure is adjusted only by the thin wall portion, there is an advantage that a sufficient effect can be obtained in a narrow space.

[Brief explanation of the drawing]

Fig. 1 is a partial cross-sectional schematic explanatory diagram of the press device, Fig. 2 is an enlarged explanatory diagram of part A in Fig. 1, and Fig. 3a, 3
Figure b is an explanatory diagram of the machining state of the workpiece, Figure 4 and the following diagrams are explanatory diagrams of an embodiment of this invention, Figures 4 and 6 are schematic diagrams of the embodiment, and Figure 4a is an explanatory diagram of the main part in a steady state. , FIG. 5 is an enlarged explanatory view of a portion A' in FIG. 4. 1,1'...Press device, 2...Ram, 3,1
9... Upper die, 4... Bolster, 5... Mandrel, 7, 14... Lower die, 6, 6'... Forging die, 1
6, 16'... Thin wall part.

Claims (1)

[Scope of utility model registration request] In a forging die structure having an upper die vertically disposed on a ram of a press machine and a lower die mounted on a mandrel erected on a bolster, which face each other, at least one of the upper die and the lower die is applied with an applied force. A forging die structure for a press device, characterized by having a pressure adjusting thin wall portion.