JPH09324771A - Molding method of scroll member - Google Patents

Abstract

PROBLEM TO BE SOLVED: To accurately mold revolving and stationary scrolls in a short time by providing a plurality of concentric circular grooves of rectangular section on the end plates of stationary and revolving scrolls on which spiral laps are not formed, and molding them by precision casting. SOLUTION: When a revolving scroll 1 formed to be combined together out of a spiral lap 2, a disc-like end plate 3, and a cylindrical boss 4 is manufactured by precision casting, a face 3b on which the boss 4 of the end plate 3 is formed (in other words, the opposite face to a face 3a formed with the lap 2) is formed with a plurality of concentric circular grooves of rectangular section. Consequently, shrinkage in the radial direction of the end plate face 3b on the boss 4 side is moderated, and hence falling of the lap 2 and warping of the end plate 3 are made small. That is, thermal shrinkage in the radial direction is balanced on both sides of the end plate 3, and the scroll can be accurately molded without falling of the lap.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method for processing a scroll member.

[0002]

2. Description of the Related Art A fixed scroll and an orbiting scroll, which are main members of a scroll compressor, are formed of gravity cast iron as described in Japanese Patent Laid-Open No. 5-79478. Further, as described in JP-A-2-197506, it is formed of an iron-based and aluminum-based sintered body by powder metallurgy.

On the other hand, as a plastic working method for a fixed scroll and an orbiting scroll, a cold forging method described in JP-A-59-13541 and a hot forging method described in JP-A-64-54806 are generally used. Is used for. As a special example, as described in JP-A-6-339740, press processing is followed by sizing, or as described in JP-A-2-173378, a wrap is formed by plate winding and then brazed to an end plate. Integrated method, JP-A-3-121201 and JP-A-4-143478
As described in Japanese Patent Laid-Open Publication No. 2003-242242, there has been invented a method in which a wrap is extruded and then brazed or friction-welded to an end plate to be integrated.

Further, JP-A-64-379 and JP-A-5-3
It is injection molded from a thermosetting and thermoplastic resin as described in Japanese Patent No. 32270.

[0005]

When the fixed scroll and the orbiting scroll are formed by gravity casting, the wrap height is 0.5 to 1.0 ° in order to facilitate the release of the formed product.
Since the draft is provided, the dimension of the molded product relative to the product dimension (hereinafter referred to as molding accuracy) is 0.8 for one side of the wrap.
~ 1.6mm larger. In addition, a chill layer is formed on the surface of a sand mold casting in relation to the cooling rate. For this reason, there has been a problem that after the molding, the product dimensions must be finished by three-step machining (precision about 5 μm) of roughing, intermediate finishing, and top finishing.

Similarly, a powder metallurgy method of molding using a mold,
Even in the cold and hot forging methods, the die machining accuracy, draft,
Due to the variation of molding conditions, the molding accuracy is 0.3-0.5mm.
A 2-3 step machining finish was required.

Further, in the method of brazing and extruding the wrap and then brazing and friction-welding it to the end plate to integrate them,
In addition to the molding accuracy of the wrap being poor, the accuracy is lowered due to the influence of deformation and displacement during joining, and the machining cost is larger than that of the integrally molded product.

Further, in the method of integrally molding by injection molding of thermosetting and thermoplastic resins, the molding precision is 0.2 to 0.2.
Since it is 3 mm, it cannot be used as a scroll member as it is and has poor machinability, so it is difficult to finish it by machining.

As described above, whichever method is used to form the scroll member, the machining cost after forming is large,
There is a problem that the manufacturing cost becomes high because of the long processing time.

Further, if the machining time of the member becomes long,
The occupying time of the processing machine becomes long, and when producing a mass-produced scroll compressor, a huge number of processing machines are required, resulting in a large capital investment.

An object of the present invention is to provide a method for forming a scroll member that solves the problems of the prior art.

[0012]

In order to achieve the above object, the present invention is a precision casting method (lost wax) in which the material for the orbiting and fixed scrolls, which is the main member of a scroll compressor, does not require a draft. In this case, a plurality of grooves having a rectangular cross section are concentrically formed on the end surface of the mirror plate on which the spiral wrap is not formed. Also, it is less than the product size.
Molded with a small size of about 05 mm (hereinafter referred to as molding accuracy of -0.05 mm or less), and a material with a very good conformability to the lap surface of the orbiting and fixed scroll base material.
A dimensional accuracy (0.005 mm or less) of the product can be achieved by performing a surface treatment of 05 mm or more, then combining both members, and performing the orbiting while rotating the orbiting scroll while pressing the orbiting scroll against the fixed scroll.

[0013]

Embodiments of the present invention will be described below in detail with reference to the drawings.

(Embodiment 1) FIG. 1 is a perspective view of the orbiting scroll 1 formed by precision casting as seen from the lap side of the material. As can be seen from the figure, the orbiting scroll 1 has a shape in which a spiral wrap 2, a disk-shaped end plate 3 and a cylindrical boss 4 are combined. 2 is a perspective view of the orbiting scroll 1 shown in FIG. 1 as viewed from the boss 4 side, the surface 3b of the end plate 3 on which the boss 4 is formed (in other words, the wrap 2 is formed). On the surface (opposite to the surface 3a), a plurality of grooves 5 having a rectangular cross section are concentrically provided.

The raw material of the orbiting scroll 1 shown in FIGS. 1 and 2 is made of carbon steel for machine structure (JIS, S25).
C) is used in the precision casting process as shown in FIG. A WAX mold is manufactured with a mold designed in consideration of a shrinkage allowance when the molten metal is cooled, and a refractory is coated on the WAX mold to form a mold. Next, the mold is heated to melt out the WAX, and the mold made of refractory is baked at a high temperature. Finally, the temperature of about 1 in the mold heated to about 1000 ℃.
Molten metal at 600 ° C is cast to form the blank for the swivel cylinder.

Since the blank material of the revolving cylinder formed by the precision casting process as described above does not need to be provided with a draft in the height direction of the wrap, the forming accuracy of the wrap is significantly improved as compared with the prior art. However, the mold size is designed in consideration of the shrinkage allowance when the molten metal is cooled.
And a disk-shaped end plate 3 and a cylindrical boss 4 are combined 3
The orbiting scroll, which has a dimensional shape, exhibits more complicated deformation behavior.

FIG. 4 shows a deformed state of the orbiting scroll when the plurality of rectangular grooves 5 of the present invention are not formed on the surface 3b of the end plate 3 on which the boss 4 is formed. The figure shows a cross section of the orbiting scroll. The orbiting scroll precision-cast as shown in the figure shows the effect of thermal contraction of the end plate 3 in the radial direction. The contraction in the radial direction of the root 2a) is larger than that of the tip 2b, and the wrap 2 is deformed into a petal shape (falls toward the outer diameter side) to deteriorate the molding accuracy. On the contrary, in the case of the mirror plate 3, the amount of contraction of the mirror plate surface 3a on the lap side in the radial direction is smaller than that of the surface 3b on the boss side due to the restraint of the wrap 2, so that the mirror plate is deformed in a convex shape.

An orbiting scroll having a wall thickness of 3 mm, a height of 16 mm, an outer diameter of a mirror plate of 86 mm, and a wall thickness of 7 mm is formed on a surface 3b of the mirror plate 3 on which the boss 4 is formed.
FIG. 5 shows an example of the forming accuracy of the lap when the lap is formed by precision casting without being formed. This figure shows the error between the forming dimension and the design dimension on the extension side of the wrap in relation to the spiral angle of the wrap, and the position in the height direction of the wrap is used as a parameter. As you can see, the lap root 2a is 0.05m.
Although it is molded with an accuracy of m or less, the accuracy of the wrap tip portion 2b is extremely poor because the wrap is deformed into a petal shape as described above. In addition, the degree becomes larger as the spiral angle becomes larger (at the end of winding the lap).

The orbiting scroll having the above-mentioned dimensions is provided with three rectangular grooves 5 each having a cross-sectional width of 4 mm and a depth of 3 mm on the surface 3b of the end plate 3 on which the boss 4 is formed, concentrically, and precision casting is performed. The deformed state of the orbiting scroll in this case is shown in FIG. In the precision-cast orbiting scroll as shown in the figure, by providing the rectangular groove, the contraction amount in the radial direction of the end plate surface 3b on the boss side is alleviated, and the collapse of the wrap 2 and the warp deformation of the end plate 3 are reduced.

FIG. 7 shows an example of the forming accuracy of the lap when such a rectangular groove is provided. As can be seen from the figure, both the lap root 2a and the lap tip 2b are molded with an accuracy of 0.05 mm or less.

According to the embodiment of the present invention, when precision-casting the orbiting scroll 1 having a shape in which the spiral wrap 2, the disk-shaped end plate 3 and the cylindrical boss 4 are combined, the boss of the end plate 3 is used. Since a plurality of rectangular grooves 5 are concentrically formed on the surface 3b on which the 4 is formed, the amount of heat shrinkage in the radial direction is balanced between the front and back sides of the end plate, and the wrap is formed without tipping, resulting in high precision. Can be molded into

(Embodiment 2) In Embodiment 1, the content of the present invention was shown for the orbiting scroll which is the main member of the scroll compressor, but in the same process the fixed scroll also has a design dimension of 0 to -0.05 mm. Can be molded with the accuracy of.

The inner and outer surfaces of the wrap 2 of the orbiting / fixed scroll thus formed and the end plate surface 3a of the end plate 3 on the wrap side are subjected to a surface treatment of a film thickness of 0 to 0.05 mm to finish to a substantially designed size. For the surface treatment, a coating with good compatibility such as a coating type solid lubricant or a self-growing coating is selected.

The surface-treated orbiting / fixed scrolls are combined on the basis of the drive shaft, and the drive shaft is rotated to cause the orbiting scroll to orbit. As a result, the surface treatment layer of the orbiting scroll and the surface treatment layer of the fixed scroll are lapped, and the gap between the surface of the orbiting scroll and the fixed scroll when the orbiting scroll makes an orbit is substantially zero. Further, in this case, since the coating film having good compatibility is selected as the surface treatment layer, the lapping process is completed in a short time.

The process of forming the orbiting / fixed scroll of the scroll compressor of the present invention is summarized in FIG.

According to the embodiment of the present invention, since the spiral wraps 2 of the orbiting scroll and the fixed scroll, which are the main members of the scroll compressor, can be finished without machining, a short time and high precision can be achieved. Can be molded into.

[0027]

According to the present invention, the orbiting and fixed scrolls of the scroll compressor can be formed with high dimensional accuracy without draft. Further, since each member is formed into a raw material with a minus tolerance with respect to the design dimension and finished by surface treatment and sliding processing, higher dimensional accuracy can be secured. In addition, since the spiral wrap of the orbiting and fixed scroll can be finished without machining, it can be molded in a short time, and the manufacturing cost is significantly reduced.

If the orbiting and fixed scroll molded in the process of the present invention is used for a scroll compressor, the compressor is operated in a state in which the clearance between the orbiting and fixed scrolls during compression operation is substantially zero. So the leakage loss is reduced,
Greatly improved performance can be achieved.

[Brief description of drawings]

FIG. 1 is a perspective view of an orbiting scroll of the present invention.

FIG. 2 is a perspective view of an orbiting scroll of the present invention.

FIG. 3 is a flow chart of forming a material for a orbiting scroll of the present invention.

FIG. 4 is an explanatory view showing a deformed state of a conventional orbiting scroll.

FIG. 5 is an explanatory diagram of forming accuracy of a wrap of a conventional orbiting scroll.

FIG. 6 is an explanatory view showing a deformed state of the orbiting scroll of the present invention.

FIG. 7 is an explanatory view of the forming accuracy of the wrap of the orbiting scroll of the present invention.

FIG. 8 is a flowchart of molding of main components of the scroll compressor of the present invention.

[Explanation of symbols]

1 ... Orbiting scroll, 2 ... Wrap, 3 ... End plate, 3a, 3
b ... End plate surface, 4 ... Boss, 5 ... Rectangular groove.

Claims (3)

[Claims] 1. In a scroll compressor for performing a compression operation by a fixed scroll and an orbiting scroll that is rotationally driven by a drive element, a cross section is rectangular on the end plate surface on which the spiral wraps of the fixed scroll and the orbiting scroll are not formed. A method for forming a scroll member, comprising forming a plurality of circumferential grooves in a concentric shape and forming by a precision casting method. 2. The molding material according to claim 1, wherein an outer line surface of the wraps of the fixed scroll and the orbiting scroll has a minus tolerance with respect to a design dimension, and an inner line surface has a plus tolerance with respect to the design dimension. A method for forming a scroll member, which comprises performing surface treatment until each surface has a substantially designed size, and then combining both members and laminating the relative surfaces. 3. The method for forming a scroll member according to claim 1, wherein the inner and outer surfaces of the wraps of the fixed scroll and the orbiting scroll are not processed by a cutting tool.