JPS62156023A - Manufacture of valve plate - Google Patents

Abstract

PURPOSE:To improve the productivity and to remarkably reduce the cost by holding a blank between two dies having a flat, smooth face and pressing the blank in a prescribed metal die to transfer the flat, smooth face to the blank. CONSTITUTION:A die unit consists of a couple of upper and lower dies 1 and 2. A surrounding metal die ring 3, and internal metal die core bars 4 and 5. Each pressing face of the dies 1 and 2 is finished to be flat and smooth. A disklike aluminum alloy blank 8 is inserted into the die unit and is pressed by a pressure of 90kg/mm<2>. Thus, the flat, smooth face is transferred to the blank 8 to form a valve plate having flat and smooth surfaces. Therefore, the productivity is improved compared with conventional cutting and grinding method.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to a method for manufacturing a valve plate used in a refrigerant compressor of an air conditioner.

[Prior art and its problems]

The valve plate is installed at the top of the cylinder of the refrigerant compressor, and is disk-shaped, with intake and discharge valve holes formed at predetermined positions. In a compressor in which a plurality of cylinders are provided in the circumferential direction as seen in Japanese Patent Application Laid-Open No. 57-97974, valve holes are formed at positions corresponding to each cylinder. An opening/closing valve is attached to each valve hole.

A compressor compresses refrigerant by reciprocating a piston within a cylinder. During the refrigerant suction stroke, the suction side valve opens, and the discharge side valve comes into close contact with the outer surface of the valve plate to close the valve hole. Close. Also, during the discharge stroke, the discharge side valve opens,
The valve on the suction side comes into close contact with the inner surface of the valve plate, closing the valve hole. Since the airtightness when the valve is closed greatly affects the performance of the compressor, the valve plate is required to have highly precise smoothness and flatness in order to maintain the airtightness.

Conventionally, this type of valve plate has been manufactured as follows. First, a disc-shaped blank is punched out of an aluminum alloy plate, and a valve hole, center shaft hole, etc. are formed at predetermined positions. Next, cut both sides of the aluminum alloy blank,
After that, it is polished with a grindstone or the like to finish the valve plate with the required surface smoothness (mirror surface) and flatness.

However, the conventional manufacturing method uses cutting and polishing with a grindstone to smooth both sides of the aluminum alloy blank, which has the problem of taking time to cut and polish, resulting in extremely low productivity. .

c. Means for Solving the Problems and Their Effects] In view of the problems of the prior art as described above, the present invention provides a highly productive method of manufacturing a valve plate using coining. Coining is a technique normally used in the production of coins, in which the material is pressurized with a die that has an uneven pattern on the pressure surface, forming an uneven pattern on the surface of the material. . Unlike the formation of such an uneven pattern, the present invention attempts to manufacture a valve plate by stamping a smooth surface (mirror surface) on an aluminum alloy blank using a die with a smooth pressing surface. .

That is, in the manufacturing method of the present invention, an aluminum alloy blank material is placed between two opposing dies with smooth pressurizing surfaces in a mold (ring and mandrel, or ring) that regulates the spread limit of the material. It is characterized by performing a coining process in between to transfer the pressurized surface of the die to the aluminum alloy blank material.

〔Example〕

First, 2017-T3 material (AI-Cu alloy, tensile strength σ
m = 49 kg/m + n"), a disc-shaped aluminum alloy blank material with an outer diameter of 119.5 mm was manufactured by punching from a plate material with a thickness of 2.0 mm, and an inner diameter of 1
A 0.1 mm valve hole and a 20.1 mm center shaft hole were formed.

On the other hand, the die unit for coining this, as shown in Fig. 1, consists of a pair of upper and lower dies 2 with pressing surfaces facing each other, a mold ring 3 placed around the dies 2, and a mold center placed inside. It consists of 4 and 5 gold. Both the pressurizing surfaces of the upper and lower dies 2 are flat, and the surface roughness Rmax
is 0.20 μm. A mold mandrel 4 for the shaft hole is projected from the center of the lower die 2, and a mold mandrel 5 for the valve hole is projected around it. The upper die 1 has recesses 6 and 7 into which the heads of the mandrels 4 and 5 fit. The inner diameter of the mold ring 3 was 120 mm, the outer diameter of the mold core 4 was 20 mm, and the outer diameter of the mold core 5 was 10 mm.

Next, 50 mg/kg was applied to both sides of the above aluminum alloy blank.
After applying a lubricant (G6311 manufactured by Nippon Craft Oil Co., Ltd.) of mmt, the aluminum alloy blank 8 was placed on the lower die 2 as shown in FIG. In this state, the upper die 1 was lowered, and the aluminum alloy blank 8 was pressed with a pressure of 90 kg/mm until it was fully spread inside the mold ring 3, and the coining process was performed.As a result, the aluminum alloy blank 8 was The pressure surfaces of the die 2 were transferred to both sides, and a valve plate with a smooth surface could be obtained.The surface of this valve plate was a mirror surface with a surface roughness Rmax of 0.20 μm, and the warpage was 2.0 μm. The accuracy as a valve plate is sufficiently satisfied.

According to various experiments, the pressurizing force P (kg/,
mm”) is the tensile strength σB (kg
/mm”) to 5 times or less, and the thickness reduction rate of aluminum alloy blank material due to coining to 4% or less.
This was effective in reducing waviness and warping of the valve plate.

In the above embodiment, an aluminum alloy blank material in which a valve hole and a center shaft hole were pre-drilled was used, but the holes may be formed after a coining process is performed on an aluminum alloy blank material without holes.

〔Effect of the invention〕

As explained above, according to the present invention, since the valve plate can be manufactured by coining with a press, the conventional cutting,
Compared to polishing, productivity is dramatically improved and costs can be significantly reduced.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a sectional view showing a method of manufacturing a valve plate according to an embodiment of the present invention. 1~Upper die, 2~Lower die, 3~Mold ring, 4/5
~Mold core metal, 8~Aluminum alloy blank material.

Claims (1)

[Claims] Coining is performed by sandwiching the aluminum alloy blank material between two facing dies with smooth pressure surfaces in a mold that regulates the spread limit of the material. A method for manufacturing a valve plate, which is characterized by transferring onto a material.