JPH04342887A - Forming metallic mold for scroll and its machining method - Google Patents

Abstract

PURPOSE:To secure the high dimensional accuracy of a scroll and to reduce frictional resistance during its machining by providing the spiral engraved mold section of a metallic mold for forming a scroll lap with a land part and a relief part for forming the scroll whose lap has no draft angle. CONSTITUTION:A forging device is provided with a lower mold 2 which supports a workpiece 1 and shares the reaction force of a forging load and a upper mold 3 provided with a spiral engraved mold section 4 to form a scroll lap 10, and moreover provided with an upper mold restraining member 5 provided with an air vent hole 6 communicating with the engraved mold, a holder 7 to hold the upper mold 3, a restraining mold 8 to restrain the radial deformation of the workpiece 1, and a boss 9. In this case, the engraved mold section 4 formed into the spiral shape of the upper mold 3 is formed of the and 4a of a parallel part to form the scroll lap 10 and a relief part 4b provided with a clearance angle alpha. Thus the scroll whose lap 10 has no draft angle can be formed with highly secured dimensional accuracy.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a scroll compressor that performs a compression operation using a fixed scroll and an orbiting scroll rotationally driven by a driving element, and more particularly to a mold for molding the scroll and a method for processing the same.

0002

2. Description of the Related Art Conventionally, the fixed and orbiting scrolls of a scroll compressor have been formed of cast iron by casting as described in Japanese Patent Publication No. 149030/1983. Further, as described in Japanese Patent Publication No. 61-232020, it is formed of an iron-based sintered body using a powder metallurgy method.

On the other hand, as a plastic working method for fixed and orbiting scrolls, the cold forging method described in Japanese Patent Publication No. 59-13541 and the hot forging method described in Japanese Patent Publication No. 64-54806 are used.

[0004] The scroll molded by the above-mentioned conventional technique is
The wrap is provided with a draft angle of 1 to 5 degrees for the purpose of facilitating release from the mold used for molding.

[0005]

[Problem to be Solved by the Invention] Since the ratio h/t (hereinafter abbreviated as aspect ratio) between the lap height h and the wall thickness t of fixed and orbiting scrolls is large, in the conventional forging process, the wrap has a draft angle. It is necessary to provide this, which deteriorates the dimensional accuracy after molding. Therefore, there was a problem that the machining allowance after forging became large and the manufacturing cost became high due to the long machining time and other reasons.

[0006] Also, during forging, the inner and outer circumferential surfaces of the wrap come into contact with the entire surface of the die engraving, so frictional resistance increases.
Moreover, since closed forging involves swaging, the machining force becomes significantly large. Therefore, there was a problem in that a large-capacity forging press was required.

An object of the present invention is to provide a die for forging a scroll and a processing method for the die, which solves the problems of the prior art described above.

[0008]

[Means for Solving the Problems] The above object is to combine the spiral carved part provided in the die that is pressed against the workpiece in the forging process with a land that forms a scroll wrap and a relief part that does not come into contact with the workpiece. High dimensional accuracy of the scroll component can be achieved by constructing the scroll component. At the same time, frictional resistance during machining can be reduced, and machining force can be significantly reduced.

Furthermore, the mold structure of the present invention can be achieved by swinging the electrode of the die-sinking electrical discharge machine to form the land and relief of the carved part at the same time.

0010

[Operation] By providing a land and a relief part in the spiral-shaped carved part of the mold and forming a wrap using the land, it is possible to form a wrap with high dimensional accuracy and a draft angle of zero. Furthermore, since the molded wrap contacts only the land of the carved part, the frictional resistance and processing force during processing are significantly reduced.

Furthermore, by oscillating the electrode formed into a predetermined shape in an arc shape with a minute diameter with respect to the center of the spiral, the amount of electrical discharge machining of the land and relief portion is different, and the amount of electrical discharge machining of the land and relief portion is different. Can be molded into sculptures.

0012

Embodiments Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 1 is an explanatory diagram of a scroll forging apparatus for a scroll compressor and a forging method thereof according to an embodiment of the present invention.

As shown in FIG. 1, the forging apparatus of this embodiment includes a lower die 2 that supports the workpiece 1 and shares the reaction force of the forging load, and a spiral-shaped carved part that forms the scroll wrap 10. 4
an upper mold 3 provided with a mold, an upper mold restraining member 5 provided with an air vent hole 6 communicating with the mold, and a holder 7 that supports the upper mold 3;
It is composed of a restraining die 8 that restrains the deformation of the workpiece 1 in the radial direction, and a boss 9. Note that the carved part 4 has a land 4a.
and a relief portion 4b.

The scroll is forged as follows. That is, as shown on the left side of FIG. 1, a workpiece 1 heated to a predetermined temperature is inserted into a lower mold 2 and a restraining mold 8. In this state, as shown on the right side of FIG.
to press against. As the upper mold 3 descends, the end plate part 11 and the boss part 12 of the scroll are formed, and the workpiece 1 plastically flows into the mold of the upper mold 3 to form the lap part 1 of the scroll.
0 is formed.

After the end plate portion 11 and the wrap portion 10 are formed, the upper die 3 is moved back (upper side in the figure), and then the scroll molded product is pushed through the lower die 2 into the restraining die 8 using a knockout punch (not shown). Push it out and take it out.

As shown in FIG. 2, the spiral-shaped carved part 4 of the upper die 3 is composed of a parallel land 4a for forming the scroll wrap 10 and a relief part 4b provided with a relief angle α. By using a mold having such a structure, it is possible to mold a scroll in which the draft of the wrap 10 is zero, as shown in FIG. 3, and it is possible to ensure high dimensional accuracy.

[0018] Furthermore, the relief portion 4b is provided to reduce the contact area with the workpiece 1 during machining, thereby reducing frictional resistance. As a result, the formability of the Al-high Si alloy workpiece having poor plastic fluidity can be significantly improved. Furthermore, since forming the wrap does not involve swaging, the processing force can be significantly reduced.

Note that even if the relief portion 4b has a stepped shape having a width larger than that of the land 4a as shown in FIG. 4, the same effect as that of the mold shown in FIG. 2 can be obtained.

The mold shown in FIGS. 2 and 4 is processed as follows.

As shown in FIG. 5(a), a spiral electrode 1 is formed with a wall thickness smaller than the width dimension of the spiral carved part 4.
3, the carved part 4 is preliminarily machined by die-sinking electrical discharge machining. After that, as shown in FIG. 5(b), the land 4a and the relief part 4b are
An electrode 14 having a cross-sectional shape similar to the predetermined shape and having a wall thickness smaller than the width of the carved part 4 is inserted into the preformed carved part 4. In this state, the electrode 14 is oscillated in an arc shape with a minute diameter about the center of the spiral, and the carved part 4 is electrically discharge-machined to a predetermined width dimension.

[0022]

According to the present invention, a scroll having a lap draft of zero can be formed, and high dimensional accuracy can be ensured. Therefore, machining after forging is shortened and manufacturing costs are also reduced.

Furthermore, since the frictional resistance during processing is reduced, the formability of Al-high Si alloy workpieces having poor plastic fluidity can be significantly improved. Furthermore, since the forming of the wrap does not involve swaging, the processing force can be significantly reduced, and the capacity of the forging press can be reduced.

[0024] By forming the molded part of the upper die, which is composed of a land and a relief part, by die-sinking electrical discharge machining, a carved part that does not penetrate the upper mold can be formed, and the rigidity of the upper mold can be ensured. . Therefore, the mold life of the upper mold is significantly improved.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a scroll forging apparatus for a scroll compressor to which a mold according to an embodiment of the present invention is applied.

FIG. 2 is a longitudinal sectional view of an upper die showing an embodiment of the present invention.

FIG. 3 is a longitudinal sectional view showing an embodiment of the scroll of the present invention.

FIG. 4 is a longitudinal sectional view of an upper die showing another embodiment of the present invention.

FIG. 5 is an explanatory diagram showing a method of processing the upper mold part of the present invention.

[Explanation of symbols]

1... Work material, 3... Upper die, 4... Carved part, 4a...
Land, 4b...Escape part, 10...Scroll wrap,
11... End plate part.

Claims (5)

[Claims] [Claim 1] In a mold for forging a scroll for a scroll compressor that performs a compression operation by a fixed scroll and an orbiting scroll rotationally driven by a driving element, a spiral carving of the mold for molding the wrap of the scroll. A mold for forming a scroll, characterized in that a land and a relief part are provided in the part. 2. The mold for forming a scroll according to claim 1, wherein the relief portion has a predetermined relief angle with respect to the land. 3. The mold for forming a scroll according to claim 1, wherein the relief portion has a stepped structure in a radial direction with respect to the land. 4. A scroll comprising a disk-shaped end plate portion and a spiral wrap portion protruding above the end plate portion,
A scroll characterized in that the wall thickness of the wrap is substantially uniform and the draft angle is zero. 5. The carved portion of the mold according to any one of claims 1 to 3, after being preformed by die sinking electrical discharge machining, has the same cross-sectional shape as the predetermined shape of the land and relief portion, and A mold machining method characterized in that electric discharge machining is performed by making an electrode formed with a wall thickness smaller than the width of a carved part oscillate in an arc shape with a minute diameter about the center of a spiral.