JPH0344348Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to a press machine for plastic working of steel plates, etc., and is particularly adapted to perform precision working.

(Prior Art) An example of a press machine is shown in Fig. 6. Generally, a press machine has a bolster 3 mounted on a bed 2 fixed to a base 1, and press-works the bolster 3. Press mold (lower mold) for
4 is now supported. Further, a plurality of columns 5 are fixed to the bed 2, and a slide 7 is attached with a press die (upper die) 6 for plastic working the workpiece in cooperation with the lower die 4.
is guided by this column 5 to move up and down. A drive source for driving the slide 7 in the vertical direction is provided in a crown 8 attached to the top of the column 5.

When plastic working a mass-produced product using such a press machine, one bolster 3 and slide 7 support a plurality of press dies, for example, four or five press dies, and the slide 7 is lowered once. In this way, all the press dies process workpieces at the same time, and the workpieces are sequentially transferred to adjacent press dies while plastic working is performed.
A press machine that performs such processing is called a transfer press, and FIG. 7 shows only the bolster 3 used in such a press. In addition, in FIG. 7, the position of the press mold 4 when performing transfer press processing is shown by imaginary lines.

A load is applied to the bolster 3 and the slide 7 when the workpiece is plastically worked by the upper and lower press dies 4 and 6, and the stress acting on the bolster 3 and the slide 7 under the maximum load state is The longitudinal distribution characteristics of distortion or deflection of the bolster 3 and slide 7 are approximately as shown in FIG. 8. As shown in FIG. 8, the amount of deflection is greatest at the center of the bolster 3. Furthermore, the 8th
Reference symbols a to d in the figure indicate the center of the stage of the press mold 4 shown by imaginary lines in FIG.

(Problem to be solved by the invention) When deflection occurs in the bolster 3 in the above-mentioned distribution state, the shape of the press product to be plasticized, that is, the workpiece, and the attachment of the press molds 4 and 6 to the bolster 3 may be affected. Depending on the position, etc., eccentric loads are likely to occur during press work, and the slide 7 under load may vibrate in the longitudinal or lateral direction in a horizontal plane, or the bolster 3 may not be able to maintain a horizontal state. .

For example, when a shell impeller of an automatic transmission as shown in Fig. 9A is used as the workpiece W and is to be formed by a transfer press, a steel plate is first draw-formed using one press, and then one after another. Trim piercing, flange processing, and slot processing are performed by passing an appropriate idle stage between these processing stages. The work W shown in FIG. 9A shows a state in which a groove G has been formed by slot machining. However, as described above, if the bolster 3 is bent, the bolster 3 will be tilted, and as shown in FIG.
is deformed, making it impossible to perform high-precision machining, or causing damage to the punch P, resulting in an excessive effect on the life of the mold. Therefore, in the past, everything from draw forming to flange processing was processed using a transfer press, and only slot processing was processed using a separate precision press without using a transfer press. This is not desirable from the viewpoint of achieving sexual improvement.

The present invention has been devised in view of the problems of the prior art described above, and aims to improve plastic working accuracy and mold life.

(Means for Solving the Problems) The present invention for achieving the above object includes mounting a bolster supporting the lower press die on a bed fixed to a base, and holding the workpiece together with the press die. A press in which a slide to which an upper press die for plastic working is attached is guided so as to be movable up and down by a column fixed to the bed, and a crown is provided on the top of the column with a built-in drive source for driving the slide. The mechanical device is characterized in that fillet holes are formed at both ends of the bolster supporting the lower press die, and an increasing section modulus portion having a larger section modulus than the both ends is formed at the center of the bolster. This is a press machine that does this.

(Function) The bolster has a thinning hole by providing holes at both ends thereof, and the central part of the bolster becomes an increasing section modulus where the section modulus is larger than that at both ends. As a result, the central portion maintains constant deflection even under maximum load, making it possible to perform highly accurate plastic working.

(Example) Hereinafter, a press machine device according to an embodiment of the present invention shown in the drawings will be described.

Figures 1 to 3 are diagrams showing the entire press machine of the present invention. The press machine shown in the figures has the same basic structure as the conventional press machine shown in Figure 6, and is different from the conventional press machine. Common parts are given the same reference numerals, but there are two bolsters 3, beds 2, and slides 7 each, and these are press mold supports that directly or indirectly support the press mold. It has become a component. still,
Between these, the press dies 4 and 6 are not shown, and in FIG. 3, the bolster 3 is shown pulled out to the front of the press machine.

FIG. 4 is an enlarged perspective view showing the bolster 3 used in the press machine of the present invention shown in FIGS. 1-3. This bolster 3 has a larger thickness than the conventional bolster 3 shown in FIG. 7, and a plurality of thinning holes 3c are formed at both ends of the bolster 3, as shown in the figure. These meat stealing holes 3c are formed in a rectangular shape. Therefore, the central part of the bolster 3 has a section modulus increasing part 3b, which has a larger section modulus than both ends, and since the section modulus of this part increases, the moment acting on the bolster 3 The maximum stress generated on the surface of the bolster 3 is reduced, and the rigidity of the bolster 3 is increased mainly at the center. FIG. 5 schematically shows the state of distortion or deflection that occurs in the bolster 3 due to the applied stress in the maximum load state of the bolster 3.

As shown in FIG. 5, if the boundaries between the increased section modulus portion 3b in FIG. 4 and the thinning holes 3c formed at both ends are P ₁ and P ₂ , the deflection of this portion is the same as in FIG. The deflection between these parts is constant compared _to other _parts , and is a part that deforms flatly.

When molding the above-mentioned shell impeller using the bolster 3 having such a structure, a press mold that does not require relatively high precision, such as a press mold for draw molding or a press mold for flange molding, is used as the first press mold. As shown by reference numerals 4a and 4d in Fig. 5, it is installed on the bolster 3 at the position where the deflection is changing, that is, on both ends, and is used for precision press molds that require high precision, such as press molds for slot machining. are installed at positions where the deflection is constant, as shown by reference numerals 4b and 4c. This makes it possible to improve the processing accuracy of slot machining, prevent damage to the slot punch of the upper die that corresponds to the lower die for slot machining attached at positions 4b to 4c, and extend the life of the die. It became.

Meat stealing holes 3c formed at both ends of the bolster 3
It is possible to take various shapes other than the rectangular shape shown in the figure, such as a circular shape, and by adjusting the amount of thinning, the amount of deflection of both ends can be adjusted. In particular, with a given thickness, the bolster 3
After forming, the amount of deflection can be arbitrarily adjusted by adjusting the amount of material stealing holes in post-processing according to the processing accuracy of the lower mold placed on both ends of the bolster 3. can.

(Effects of the invention) As described above, according to the invention, in a press machine device, a thinning hole is formed at both ends of a bolster that supports a lower press die, and a hole is formed in a central portion of the bolster from both ends. By forming a section modulus increasing part with a large section modulus, the deformation of the center part during the maximum load applied to the bolster is ensured to be flat,
It has become possible to plastically process workpieces with precision and high precision. In addition, since the press die was installed accurately, deformation and breakage of the press die were prevented, and the life of the die was improved. In particular, for transfer presses that have multiple press dies, the press dies that require high-precision processing are installed in the center, and the press dies that do not require relatively high precision are installed at both ends. By making slight changes to the conventional press machine, it becomes possible to carry out transfer molding of the workpieces while sequentially transporting the workpieces, including high-precision machining.

[Brief explanation of drawings]

FIG. 1 is a front view of a press machine according to an embodiment of the present invention, FIG. 2 is a side view of FIG. 1, FIG. 3 is a plan view showing the bolster in FIG. 1, and FIG.
The figure is an enlarged perspective view showing the bolster of the present invention.
The figures are graphs showing the deflection distribution of the bolster of the present invention under maximum load, Figure 6 is a side view of a conventional press machine, Figure 7 is a perspective view of the conventional bolster in Figure 6, and Figure 8 is a graph showing the deflection distribution of the bolster shown in FIG. 7 in the maximum load state, and FIGS. 9A and 9B are sectional views each showing a part of the workpiece. 1... Base, 2... Bed, 3... Bolster, 4, 6... Press mold, 5... Column, 7...
Slide, 8...Crown.

Claims (1)

[Scope of utility model registration request] A bolster supporting the lower press die is mounted on a bed fixed to a base, and a slide to which an upper press die for plastically forming the workpiece is attached is attached by a column fixed to the bed. In a press machine device, the press machine is provided with a crown that guides the column so as to be movable up and down and has a built-in driving source for driving the slide at the top of the column,
A press machine device characterized in that fillet holes are formed at both ends of a bolster supporting the lower press die, and an increasing section modulus portion having a larger section modulus than the both ends is formed at the center of the bolster. .