JPH02147141A - Manufacture of forging die - Google Patents

Abstract

PURPOSE:To improve the productivity of a forging die by mounting a master model on a lower coining punch, then, putting an upper coining punch and an upper die on them, then, grinding the upper surfaces of both the upper coining punch and the upper die to the same level. CONSTITUTION:The lower coining punch 3 and the lower die 5 are mounted on a lower side forging machine body 10. Under this reference, the master model 9 is mounted on the lower coining punch 3, then, upper coining punch 2 and the upper die 4 are mounted. The upper surfaces of the upper coining punch 2 and the upper die 4 are ground so that they are arranged on the same level within a prescribed tolerance.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application 1] The present invention relates to a method for manufacturing a forging die for cold coining.

[Prior Art] For example, the thickness dimension of the sliding surface 7 of the steering yoke 8 shown in FIG. 4 with respect to the resin ball is required to have a high precision of ±0.05 mm.

Such high-precision forging is performed by cold coining.

That is, as shown in FIG. 5, the rough section 6 is sandwiched between the upper coining punch 2 and the lower coining punch 3 inserted into the upper die 4 and the lower die 5, respectively, and the forging machine main body 10.10' Press to coin. At this time, the thickness accuracy of the product is adjusted using the end stopper 1.

In addition, since the thickness dimensional accuracy of the product is determined by the end stopper l, the lower forging machine body lO and the upper forging machine body 10'
It is necessary that the upper surfaces of the upper die 4 and the upper coining punch 2 and the upper surfaces of the lower die 5 and the lower coining punch 3 are flush with each other so that they uniformly hit the flat surface of the coining punch 2.

Conventionally, in the production of such forged shapes, the upper and lower dies and the upper and lower coining punches were individually machined.

In this way, in the past, the upper and lower dies and the upper and lower coining punches were processed separately, which caused the following problems.

In other words, the above machining (grinding) accuracy is ±0.
．． High-precision processing such as 0.01 mm is performed, but when these individual parts are assembled as a forging die, there is a problem in that assembly errors inevitably occur.

For example, even if the processing accuracy of the upper and lower dies and the upper and lower coining punches is ±0.01 mm, the assembly accuracy of the forging die will vary within a range of ±0.05 mm.

And, like the steering yoke, the dimensional accuracy is ±0.
If 0.05 mm is required, the forging die cannot provide that precision.

Therefore, at present, the thickness of the end stopper is adjusted by testing several dozen pieces and calculating the average value.

Therefore, there was a problem in that it took a long time to start production and the productivity was extremely low.

In addition to the variations in the assembly accuracy of the forging dies themselves, there are also variations in the forged products themselves, so there is a slight discrepancy between the average value of the trial stamping and the average value for the total number of products produced in mass production. There is a quality problem.

[Means to solve the problem]

In order to solve the above problems, the present invention places a lower coining punch and a lower die on the lower forging machine body, uses this as a reference, then places the master model on the lower coining punch, and then It is characterized in that a coining punch and an upper die are mounted, and the upper surfaces of the upper coining punch and the upper die are ground to be flush within a predetermined tolerance range.

[Function] By doing so, the forging die is machined with high precision in the assembled state.

Then, the coined product is coined with high precision using a master model that is created in consideration of coining conditions so that the dimensions of the coined product become predetermined dimensions.

[Example] An example of the present invention will be described in detail below. First, in FIG. 3, the master model 9 is created as follows.

For example, when the sliding surface 7 of the steering yoke 8 with the resin ball shown in FIG. 4 is coined, a predetermined dimensional accuracy (for example, ±0.05 mm) is obtained when the sliding surface 7 is coined. The master model 9 is created by conducting experiments according to the coining conditions, determining the angle θ and the thickness t at the average diameter of the master model 9.

Then, as shown in FIGS. 1 and 2, the inclination angles of the shoulders 13 of the upper coining punch 2 and the lower coining punch 3 are made to match the angle θ of the master model 9.

Next, in FIG. 1, the lower die 5 and lower coining punch 3 are set and placed on the lower forging machine main body lO, and the master model 9' is shown when the master model 9 is fitted into the lower coining punch 3. The contact of the lower coining punch 3 and the lower die 5 in contact with the lower forging machine main body IO is adjusted so that the height H of the center C and the step difference ΔH between the upper surface of the lower die 5 and the center C are dimensions with predetermined accuracy. Grind the contact surface.

In processing the dimensions H and ΔH, the lower coining punch 3 is movable in the vertical direction within the deep hole 11 provided in the lower die 5.

Regarding the steering wheel 8 shown in FIG. 4, it is the sliding surface 7 that requires highly accurate machining dimensions, so the dimensions H and ΔH do not require very high accuracy.

Next, in FIG. 1, the master model 9 is fitted into the lower coining punch 3 as indicated by 9'.

Then, as shown in FIG. 2, the upper die 4 is set with the end stopper 12 interposed therebetween, and then the upper coining punch 2 is set.

In this state, referring to FIG. 2, the upper surface of the upper coining punch 2 is higher than the upper surface of the upper die 4 by Δh. Of course, the upper surface of the upper coining punch 2 may be lower.

Next, set this level difference Δh within a predetermined tolerance range, for example ±0.01.
Grind it to mm.

The following three methods can be considered for this grinding process. One of them is the case where the upper surface of the upper coining punch 2 and the upper surface of the upper die 4 are simultaneously ground in the state shown in FIG.

In this grinding process, for example, the machining accuracy of Δh is ±0.01m.
m, whereas the actual Δh is, for example, ±0.015 m.
It is effective for very minute grinding such as m.

If the accuracy is ±0.01 mm and Δh is 0.1 mm, the second method of grinding only the upper surface of the upper coining punch 2, as shown in FIG. 2, can be considered.

As a third means, if the grinding accuracy is ±0.01 mm and Δh is ±0.015 mm, select the end plate 12 that is +0.015 mm thicker than the end plate 12 currently in use. Alternatively, if the upper surface of the upper coining punch 2 is lower, the end plate 12 may be ground by 0.015 mm.

In any case, the most suitable grinding means is selected according to the situation at the time, and the upper surface of the upper coining punch 2 and the upper surface of the upper die 4 are ground so that they are flush with each other within a predetermined tolerance range of accuracy. .

In this way, by performing the grinding process with the forging die assembled, it is not affected by assembly errors, and in the above numerical example, the accuracy of the assembled forging die is ±0.01 mm.

Therefore, if you use a forging die with this accuracy to coin a product that requires an accuracy of ±0.05 mm, you will be able to achieve a coining accuracy of ±0.05 mm without the need for test punching and confirmation using the average value.
It is easy to keep the accuracy within 0.5 mm.

[Effects of the Invention 1] As detailed above, according to the present invention, the lower coining punch and the lower die placed on the lower forging machine body are used as a reference,
Since the upper coining punch and upper die are ground using the master model, they are processed as an assembled forging die.

As a result, a high-precision forging die that is unaffected by assembly errors is obtained, eliminating the need for trial stamping, and greatly reducing the cost of materials used for trial stamping. This eliminates all of the time spent, greatly improving productivity.

In addition, since the precision of the forging die is improved, the quality of the product is also improved, and since there are no defective products, the yield is also improved.

Since the mold is precision-machined in an assembled state, the precision of each mold member does not need to be so high, and the mold can be manufactured in a short time.

[Brief explanation of the drawing]

1 to 3 show one embodiment of the present invention, in which FIG. 1 is a longitudinal cross-sectional view showing a lower coining punch and a lower die placed on the lower forging machine body, and FIG. In the state shown in FIG. 1, a vertical cross-sectional view shows a state in which an upper coining punch and an upper die are set with a master model interposed therebetween, and FIG. 3 is a vertical cross-sectional view of the master model. FIG. 4 is an explanatory diagram showing a plan view of the steering yoke. FIG. 5 is an explanatory diagram showing a longitudinal section of the forging die, and FIG. 6 is an enlarged longitudinal sectional view of section A in FIG. 2... Upper coining punch, 3... Lower coining punch, 4... Upper die, 5...
...Lower guide, 9...Master model, 10...Lower forging machine body, lO'...Upper forging machine body, 12...
・End stopper. Patent Applicant: Toyota Motor Corporation (2 idiots) Fang Figure 3, lower fi; Shiku'ki 5+ 9, Master Seven Tee 5-Bottom Chiisu 10 Lower Ai Genkai 11 machine body Fang Figure 12...Need strike 7 ha 0 Diagram

Claims (1)

[Claims] Place the lower coining punch and lower die on the lower forging machine body and use this as a reference. Next, place the master model on the lower coining punch, then place the upper coining punch and upper die, and then A method for manufacturing a forging die, comprising grinding so that the upper surface of the upper die is flush with the upper die within a predetermined tolerance.