JP2831090B2 - Cold plastic working method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a cold plastic working method for finishing a required portion of a work surface of a work with high accuracy.

<Conventional technology> Generally, parts that need to be formed with high precision, such as side plates of a vane pump, having complicated shapes formed on the side surface are made of a highly ductile aluminum alloy wrought material.
After the material was formed by hot extrusion, finishing was performed with high precision by cold plastic working or cutting.

In recent years, in order to reduce costs, it has been attempted to form a component having a complicated groove on a side surface with high precision using a brittle material such as an aluminum alloy casting material.
In this case, the material is cast and formed by die casting or the like, and then finished by cutting.

<Problems to be Solved by the Invention> However, the method of finishing the cast material by cutting as described above cannot be processed with high efficiency and is not sufficient in terms of cost reduction. However, if it is attempted to finish the cast and formed material by cold plastic working in order to process with high efficiency, this material is a brittle material, so cracking and chipping occur, which is not possible.

<Means for Solving the Problems> The present invention has been made to solve the above-described problems, and a cold plastic forming method in which a processing surface of a plate-shaped material is pressed against a lower mold and the processing surface is formed. In the processing method, the material is held movably in the vertical direction by a holding member with respect to a pressing member that presses the material from above, and further, the material is moved by the pressing member at a positioning portion that is formed to project below the pressing member. A material restraining portion having an inner circumference smaller than the outer shape of the material formed on a template positioned on the side surface of the lower mold by pressing the material in the lateral direction by pressing the material. Pushing while fitting to the, after that, by pressing the processing surface of the material to the male mold formed only on the required portion of the lower die upper surface by the pressing member, the required portion of the processing surface is plastically processed. It was done.

<Operation> The material made of brittle material cast and formed by die casting or the like is held in the vertical direction by the holding member, and is positioned in the horizontal direction by the positioning portion, and is fitted into the material restraining portion of the template by the lowering of the pressing member. It is pushed in while being combined, and is brought into a restrained state by the material restraining portion. Thereafter, the pressing member further descends, and the processed surface of the material is pressed against the male mold formed only on the required portion of the lower die upper surface, and the required portion of the processed surface is plastically deformed with high precision.

<Example> The overall structure of a press machine for performing cold plastic working according to the present invention will be described with reference to FIG. Reference numeral 1 denotes a material used for a side plate of a vane pump, which is made of a brittle aluminum alloy casting material. The shape of the material 1 is shown in FIG.
As shown in the figure, it has a substantially disk shape with a through hole 1a provided in the center, and one side surface is a processed surface 1b to be plastically processed, and a plurality of grooves 1c of a complicated shape are formed. Being
The shapes of the grooves 1c need to be formed with high precision in order to ensure the performance of the vane pump.

A pressing member 5 for pressing the material 1 from above is slidably held in a vertical direction by a known mechanism (not shown), and a large force is applied particularly when sliding in a downward direction. Below the pressing member 5, a positioning portion 6 is integrally formed to protrude. The positioning portion 6 has a substantially cylindrical shape having a tapered portion at the tip, and the through hole 1a of the material 1 is provided.
And functions to position the upper die 5a provided on the lower end surface of the pressing member 5 in the lateral direction. Also, the outer diameter is slightly larger than the inner diameter of the through hole 1a,
By inserting the material 1 into the through-hole 1a, a compressive stress is generated in the material 1. Further, the tip of the positioning portion 6 is inserted into a guide hole 2c formed in the lower mold 2 placed below the pressing member 5, and the material 1 is moved in the lateral direction with respect to the lower mold 2. We are positioning.

The pressing member 5 is provided with three rod-shaped holding members 7 that penetrate the pressing member 5 so as to be vertically slidable. The upper ends of the holding members 7 are fixed to a piston 11 that slides in a cylinder 10 provided in the pressing member 5,
A spring 14 is interposed in the upper chamber of the piston 11 and presses the piston 11 downward.

The lower mold 2 has a substantially cylindrical shape with an outer diameter slightly smaller than the outer circumference of the material 1, and the upper surface 2 a of the lower mold 2
By pressing 1b, it is a male mold 2b that partially deforms plastically. Further, the lower die 2 is provided with three rod-shaped holding members 8 that penetrate the lower die 2 so as to be slidable in the vertical direction, and the lower end of the holding member 8 is provided below the lower die 2. The piston 13 is fixed to a piston 13 that slides inside the cylinder 12 and slides up and down by the vertical movement of the piston 13 due to hydraulic pressure.

Further, a template 3 is placed on the outer periphery of the lower mold 2. The surface of the mold plate 3 that is in contact with the lower mold 2 is located above the upper surface 2a of the lower mold 2 and forms a material restraining portion 4. Lower mold 2
The inner diameter of the material restraining portion 4 equal to the outer diameter of the material 1 is slightly smaller than the outer diameter of the material 1 and acts to restrain the material 1 in the lateral direction during plastic working.

The cold plastic working performed by the press having the above configuration will be described in order with reference to FIGS. First, the raw material 1 formed by casting is, as shown in FIG. 4, the holding member 7 from above and the holding member 8 from below,
It is held in a state where it is located above the lower mold 2 and separated from the lower mold 2.

Thereafter, the pressing member 5 is moved downward by a known mechanism (not shown). While the pressing member 5 is descending, the positioning portion 6
Is inserted into the through hole 1a of the material 1 to position the material 1 in the lateral direction with respect to the pressing member 5, and to generate a compressive stress in the material 1. The upper surface of the material 1 is the upper die 5a of the pressing member 5.
When the pressing member 5 moves downward to a position where the pressing member 5 contacts the cylinder 12 (FIG. 1), hydraulic pressure acts on the cylinder 12 (FIG. 1).
Is controlled so that the holding member 8 descends at the same speed as the moving speed. As the holding member 8 descends, the holding member 7 also descends following the elastic force of the spring 14. Then, as shown in FIG. 5, the processing surface 1b of the material 1 is brought into contact with the upper surface of the template 3, and the positioning portion 6 is inserted into the guide hole 2c.

When the pressing member 5 moves further downward from the state shown in FIG. 5, the outer diameter D (FIG. 4) of the material 1 is larger than the inner diameter D0 (FIG. 4) of the material restraining portion 4. As shown in FIG. 6, the material 1 is fitted into the material restraining portion 4 and is pushed in. In this state, the material 1 is restrained by the positioning portion 6 and the material restraining portion 4, and compressive stress is generated in the material 1.

Thereafter, the pressing member 5 is further lowered, and as shown in FIG. 7, the material 1 is processed into the male mold 2b provided only in the portion of the upper surface 2a of the lower mold 2 which needs to be formed with high precision. Face 1b
Is pressed, the groove 1c formed on the processing surface 1b is plastically deformed, and is molded with high precision.

As described above, only the necessary portion of the processed surface of the material made of the aluminum alloy casting material, which is a brittle material, is restrained by the positioning portion 3 and the material restraining portion 4 so that the material 1 is subjected to the compressive stress. By performing cold plastic working by pressing against the mold, it is possible to prevent the occurrence of cracks and chipping due to the use of brittle materials, and it is possible to work with high efficiency while securing the required high accuracy. It has become possible.

<Effects of the Invention> As described above, according to the present invention, only a necessary portion of a processed surface of a material is constrained by a material constraining portion and a compressive stress is generated in the material. Since plastic processing is performed, even when a brittle material such as an aluminum alloy casting material is used as a material, it is possible to prevent the occurrence of cracks and chipping, while securing the required high accuracy, It has become possible to process with high efficiency.

[Brief description of the drawings]

FIG. 1 is a view showing the entire structure of a press machine for performing cold plastic working of the present invention, FIG. 2 is an overall view of a material, and FIG. 3 is a cross-sectional view taken along line III-III in FIG. FIGS. 4 to 7 are cross-sectional views showing the steps of the cold plastic working of the present invention.
FIG. 4 is a view showing a material holding state, FIG. 5 is a processing start view, and FIG.
The figure is a drawing in the middle of processing, and FIG. 7 is a drawing showing the completion of processing. 1 ... material, 1b ... processing surface, 2 ... lower mold, 2a ... upper surface,
2b: male mold, 3: mold plate, 4: material restraining section, 5: pressing member, 6: positioning section, 7, 8 ... holding member.

Claims (1)

(57) [Claims] In a cold plastic working method in which a work surface of a plate-shaped material is pressed against a lower mold and the work surface is formed, a holding member presses the material from above with a holding member. Movably held in the direction, and further, the material is pressed in the lateral direction by pressing the material with the pressing member at a positioning portion projecting below the pressing member,
In this state, the material is pressed by the pressing member while being fitted into a material restraining portion having an inner periphery smaller than the outer peripheral shape of the material formed on the template located on the side surface of the lower mold, and then the pressing is performed. A cold plastic working method in which a required surface of the processing surface is plastically processed by pressing a processing surface of the material onto a male mold formed only on a required portion of the lower die upper surface by a member.