JP2000240578A - Manufacture of chip seal for scroll compressor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the accuracy of a size and yield by extrusion molding a resin composition comprising fluorocarbon resin as a main component to a cylindrical molding body, cutting the cylindrical molding body in a ring shape to form ring shaped members, and giving spiral cutting-work to the ring shaped member from an outer peripheral surface toward an inner circumference surface. SOLUTION: In the case where a chip seal is manufactured, a resin composition comprising fluorocarbon resin as a main component is extrusion molded to a cylindrical molding body 1. The cylindrical molding body 1 is cut in a ring shape to form in a plurality of ring shaped members. The ring shaped members are spirally cut worked from an outer peripheral surface toward an inner circumferential surface. Namely, the ring shaped members are attached to a turning lathe, and for example, is turned to a spiral body 2a having prescribed thickness, width, and length. The spiral body 2a is cut to an expansion length of the chip seal, and an outline is finished to complete the chip seal. The chip seal may be fit to a seal groove in the spiral body shape, or it is fitted to the seal groove by forming beforehand.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a tip seal used in a scroll compressor.

[0002]

2. Description of the Related Art In a scroll type compressor, a substrate and a fixed scroll and a movable scroll having a spiral wall erected on the surface of the substrate are meshed with each other at the spiral wall to form a compression chamber therebetween. I have. The compression chamber moves toward the center of the spiral by the action of a movable scroll that revolves around the axis of the fixed scroll to compress gas or the like. In order to ensure the tightness of the compression chamber when compressing gas, etc., a tip seal groove is formed along the extension direction of the spiral on the end surface of the spiral wall of the fixed scroll and the movable scroll, and the opposed scroll is formed in this groove. A tip seal, which is a spiral seal member that contacts the substrate, is housed. Most of the tip seal has a square cross section, is accommodated in the groove with a gap, and floats from the bottom of the groove toward the scroll substrate due to the pressure of gas or the like between the groove and the scroll substrate facing each other. Seal between the spiral walls.

Conventionally, chip seals are roughly classified into two types. One tip seal is used for a scroll type compressor for a refrigerating cycle such as a refrigerator or an air conditioner, and a lubricating oil is used in combination with a refrigerant. Therefore, the chip seal is required to have chemical resistance in addition to the sealing property, but since lubricating oil is interposed, the required properties for the sliding property of the seal material itself are relatively strict. This tip seal is made by injection molding a resin composition that has improved sliding characteristics by blending a solid lubricant with a resin that has high heat resistance and chemical resistance, such as polyphenylene sulfide resin and polyetheretherketone resin. Manufactured products are used. The other is used for a scroll type compressor used for medical, horticultural use, hobby use, health equipment use, decompression of a vacuum container such as a thermos bottle, etc., and is used without lubrication. Therefore, the tip seal needs to have a sealing property, a chemical resistance, and a sliding property and abrasion resistance even without lubrication, and the required properties regarding the sliding property and the abrasion resistance are relatively strict. No such sealing material satisfying the required characteristics has been found other than a resin material containing a fluororesin as a base material, and the entire surface is formed by machining. Also,
Even with a scroll compressor that uses lubricating oil,
Depending on the use conditions, a problem such as melting and abrasion occurs with polyphenylene sulfide resin, polyether ether ketone resin, or the like. Therefore, a resin material based on a fluororesin is used.

[0004]

However, since the fluororesin composition cannot be injection-molded, there is a problem that a chip seal with stable dimensional accuracy cannot be obtained. For example, when producing a chip seal using a fluororesin composition, first, a sheet material having a uniform thickness is punched out with a spiral-shaped punch die of the chip seal. It is difficult to produce a high-quality chip seal. Conventionally, to deal with the problem of unstable dimensional accuracy, the tip seal groove of the scroll wrap has been processed into a large groove, but this has been caused by dropping from the groove of the tip seal during assembly and the large gap. There is a problem that uneven wear of the tip seal or the like occurs due to the tip seal falling down. In addition, the method of punching with a punch mold has a low yield and generates a large amount of waste material.
There is a problem that productivity is poor.

SUMMARY OF THE INVENTION The present invention has been made to address such a problem, and it is an object of the present invention to provide a method for manufacturing a chip seal made of a fluororesin composition having good dimensional accuracy, high yield and excellent productivity. With the goal.

[0006]

According to a first aspect of the present invention, there is provided a method for manufacturing a tip seal for a scroll type compressor, comprising the steps of: extruding a resin composition containing a fluororesin as a main component into a cylindrical molded body by an extrusion molding method; Cutting the cylindrical molded body into a ring-shaped member by cutting it into a ring-shaped member; and spirally cutting the ring-shaped member from the outer peripheral surface toward the inner peripheral surface to fit the chip seal groove. And forming a spiral shape.

According to a second aspect of the present invention, there is provided a method of manufacturing a tip seal for a scroll type compressor, comprising the steps of: extruding a resin composition containing a fluororesin as a main component into a cylindrical molded body by an extrusion molding method; Spirally cutting from one end face toward the other end face to form a spiral fitting into the chip seal groove.

A method of manufacturing a tip seal for a scroll compressor according to claim 3, wherein a resin composition containing a fluororesin as a main component is extruded into a cylindrical molded body by an extrusion molding method; Cutting into a ring-shaped member to form a ring-shaped member, and a step of forming the ring-shaped member into a spiral shape to be fitted into the chip seal groove by cutting the ring-shaped member at one place in the diameter direction. I do.

In the present invention, the extrusion molding method refers to a ram extrusion molding method and a paste extrusion molding method used for an ethylene tetrafluoride resin composition.

[0010] The present invention is also characterized in that the fluororesin is at least one resin selected from ethylene tetrafluoride resin and modified tetrafluoroethylene resin.

According to the present invention, a resin composition containing a fluororesin as a main component is formed into a cylindrical molded body by extrusion molding, and the cylindrical molded body is cut into a spiral shape to be fitted into a chip seal groove. Thereby, a tip seal having excellent dimensional accuracy and productivity can be obtained.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described with reference to FIGS. FIG. 1 is claim 1, FIG. 2 is claim 2,
FIGS. 3A and 3B are schematic views showing the steps of manufacturing the tip seal according to the third aspect, respectively, and FIG. 4 is a perspective view of the tip seal. In the manufacturing process of the chip seal of the first aspect, first, a resin composition containing a fluororesin as a main component is molded into a cylindrical molded body 1 by an extrusion molding method (FIG. 1A). A specific example of a method for forming a cylindrical molded body by a ram extrusion molding method is described below. 1) A predetermined amount of a fluororesin powder and various compounding materials are sampled. 2) The collected raw materials are uniformly mixed with a mixer, for example, a tumbler mixer, a Henschel mixer or the like. 3) The uniformly mixed raw materials are put into a ram extrusion molding die, and molded at a pressure of 30 to 80 MPa and a temperature of 350 to 390 ° C. 4) After the cylindrical compact is cooled to room temperature, it is baked at 150 ° C for 10 hours or more using a heating furnace to eliminate internal stress. 5) The fired compact is cooled to room temperature to obtain a cylindrical compact 1.

Next, the cylindrical shaped body 1 is cut into a ring and formed into a plurality of ring-shaped members, and the ring-shaped members are spirally cut from the outer peripheral surface toward the inner peripheral surface (FIG. 1). (B)). Specifically, a ring-shaped member cut into a predetermined width dimension is attached to a lathe, and is turned into a spiral-shaped body 2a having a predetermined thickness, width and length while being rotated 1 to 3 times (see FIG. 1 (c)).

The spiral seal 2a is cut to the developed length of the tip seal and the outer shape is finished, whereby the tip seal shown in FIG. 4 is completed. When the tip seal is fitted into the seal groove, it may be fitted along the seal groove as a spiral body having an externally finished shape, or shaped into a chip seal shape in advance and fitted into the seal groove. Is also good. As a method for shaping into a chip seal shape, a method in which a chip is put into a container having the same shape as the seal groove and heated, or the like can be adopted. As described above, according to the present invention, since a spiral body having excellent dimensional accuracy is formed in advance and then shaped into a chip seal, a chip seal having no dimensional loss and excellent in dimensional accuracy can be manufactured.

In the manufacturing process of the chip seal according to the second aspect, first, a resin composition containing a fluororesin as a main component is molded into a cylindrical molded body 1 by an extrusion molding method (FIG. 2A).
The method of manufacturing the cylindrical molded body 1 can employ the same method as the above-described manufacturing process of the tip seal of claim 1. However, in this case, the thickness of the cylindrical molded body 1, that is, the length of (outer diameter−inner diameter) / 2 is either the width t ₁ or the height t ₂ of the tip seal shown in FIG. Mold as follows. In consideration of the spiral shape of the tip seal, it is preferable to set the thickness of the cylindrical molded body 1 so as to have the width t _{1 of the} tip seal.

Next, the cylindrical shaped body 1 is spirally cut from one end face to the other end face (FIG. 2).
(B)). Specifically, the cylindrical molded body 1 is mounted on a lathe, and is turned into a spiral body 2b having a predetermined width and length while being rotated one to three times, and cut into a developed length of the tip seal (FIG. 2). (C)).

Next, by finishing the outer shape, the tip seal shown in FIG. 4 is completed. In addition, as a method of shaping into a chip seal shape, the same method as the above-described manufacturing process of the chip seal of claim 1 can be adopted. Can be manufactured.

In the manufacturing process of the chip seal according to the third aspect, first, a resin composition containing a fluororesin as a main component is molded into a cylindrical molded body 1 by an extrusion molding method (FIG. 3A).
The method of manufacturing the cylindrical molded body 1 can employ the same method as the above-described manufacturing process of the tip seal of claim 1. However, in this case, the thickness of the cylindrical molded body 1, that is, the length of (outer diameter−inner diameter) / 2 is either the width t ₁ or the height t ₂ of the tip seal shown in FIG. Mold as follows. In consideration of the spiral shape of the tip seal, it is preferable to set the thickness of the cylindrical molded body 1 so as to have the width t _{1 of the} tip seal.

Next, the cylindrical molded body 1 is cut into a ring and formed into a plurality of ring-shaped members, and the ring-shaped member is cut at one position in the diameter direction of the cylindrical molded body 1 to form a C-shaped member. A body 2c is obtained (FIG. 3 (c)). Specifically, the cylindrical molded body 1 is turned into a ring-shaped member by using a lathe, and then one portion of the ring-shaped member is cut.

The tip seal of the present invention is manufactured from a fluororesin composition containing a fluororesin as a main component and various additives. The compounding agent is not particularly limited, and examples thereof include a reinforcing material, an abrasion resistance imparting material, a lubricating property improving material, an anti-creep material, and an antioxidant material. The fluororesin is at least one resin selected from a tetrafluoroethylene resin and a modified tetrafluoroethylene resin. The tetrafluoroethylene resin is a high-molecular-weight resin having —CF ₂ —CF ₂ — as a structural unit, and is a resin that can be compression-molded but cannot be injection-molded. As a commercially available product, Teflon 7J manufactured by Mitsui-DuPont Fluorochemical Co., Ltd.
Etc. can be exemplified.

The modified tetrafluoroethylene resin is -CF _2-
A structural unit composed of CF ₂ — and a perfluoroalkyl ether group (—C _p F _2p —O—) (p is an integer of 1 to 4) or a polyfluoroalkyl group (H (CF ₂ ) q—) (
(q is an integer of 1 to 20) is a copolymer with a tetrafluoroethylene structural unit. This modified tetrafluoroethylene resin is different from PFA which is a copolymer of ethylene tetrafluoride and perfluoroalkyl vinyl ether in that it has non-melt moldability. Commercially available modified tetrafluoroethylene resin includes Mitsui DuPont Fluorochemical Co., Ltd .:
Teflon TG70J, manufactured by Daikin Industries: Polyflon M
111, polyflon M112, manufactured by Hoechst: Hostaflon TFM1600, Hostaflon TFM1700, and the like.

Various compounding agents to be compounded in the fluororesin composition will be described. In particular, carbon fibers, inorganic fibers, and organic fibers acting as a reinforcing material, a wear resistance-imparting material and a creep preventing material, and copper-based alloy powder acting as a wear resistance-imparting material and a lubrication property improving material will be described. The carbon fiber used in the present invention may be any of pitch-based, PAN-based, carbonaceous, and graphite-based.

Commercially available carbon fibers are available as pitch-based products from Kureha Chemical Co., Ltd .: Crecamild M101S, M101F, M
101T, M107S, M1007S, M201S, M
207S, manufactured by Osaka Gas Chemical Company: Donna Carbon S24
1, S244, SG241, SG244 as PAN system, manufactured by Toray Co., Ltd .: Trekamild Fiber MLD30,
Toho Rayon Co., Ltd .: Vesfight HTA-CMF016
0-0H and CMF0070-0H.

Further, graphite can be used as the wear resistance imparting material. The graphite is not particularly limited, and natural graphite or an organic substance may be used.
Artificial graphite fired at 0 ° C to 3000 ° C may be used. Further, the shape may be any of a spherical shape, a scale-like shape and an irregular shape.

It is preferable that the inorganic fibers and the organic fibers withstand the molding temperature of the fluororesin composition, for example, a temperature of 320 ° C. to 400 ° C. Examples of the fibers include whiskers such as calcium carbonate whiskers, titanium oxide whiskers, zinc oxide whiskers, calcium sulfate whiskers, wollastonite, potassium titanate whiskers, carbon whiskers, silicon carbide whiskers, and sapphire whiskers; Examples thereof include so-called boron fibers obtained by depositing boron, silicon carbide, or the like on fibers, composite fibers such as silicon carbide fibers, and heat-resistant organic fibers such as aromatic polyimide fibers.

The copper-based alloy powder is a powder of a copper alloy, for example, bronze or brass, and is not particularly limited. Copper-tin alloy,
Eutectic powders such as copper-lead alloys or copper-lead-tin alloys are particularly preferable because of their excellent wear resistance. The shape of the copper-based alloy powder may be spherical, flaky, needle-like, teardrop-like, or other well-known powder shapes, but spherical powder is particularly preferable because of its low friction coefficient and good wear resistance.

Another compounding agent that acts as a reinforcing material, an abrasion resistance imparting material and a creep preventing material is a polyimide resin powder. As the polyimide resin that can be used in the present invention, a thermosetting resin or a thermoplastic resin can be used as long as the polyimide resin does not decompose at the firing temperature of the fluororesin composition. Commercially available products are P84 manufactured by Ranging Co., UIP-S, UIP manufactured by Ube Industries, Ltd.
-R, manufactured by Mitsui Chemicals, Inc .: AURAM PD450.

[0028]

EXAMPLES Raw materials used in Examples and Comparative Examples are collectively shown below. In addition, [] shows the symbol in Table 1, and the compounding ratio in Table 1 is all weight%. 1) Teflon 7J manufactured by DuPont Fluorochemicals Co., Ltd. 2) Teflon TG70J manufactured by DuPont Mitsui Fluorochemicals 3) Carbon fiber [CF] Toray 4) Copper alloy [BROZ] Fukuda Metal: AT350 5) Inorganic whisker [IOF] Otsuka Chemical: Tismo N 6) Thermosetting polyimide resin [PI] Ube Industries:
UIP-S 7) Thermoplastic polyimide resin [TPI] manufactured by Mitsui Chemicals, Inc .: AURAM PD450

Examples 1 to 4 The above-mentioned raw materials were collected at the mixing ratios shown in Table 1, and these were thoroughly mixed using a Henschel mixer. This mixed material was filled into a ram extrusion die (Uchinori dimensions: outer diameter 110 mm, inner diameter 90 mm, total length 1000 mm) heated to 320 to 390 ° C., and was molded at a pressure of 50 MPa. The cylindrical molded body was removed from the mold, cooled to room temperature, heated at 150 ° C. for 20 hours and annealed.

The cylindrical molded body is passed through a cutter having a cutter interval of 2 mm to produce a ring-shaped member, and the ring-shaped member is spirally cut from the outer peripheral surface to the inner peripheral surface to a thickness of 3 mm. A rod-shaped chip seal material having a width of 3 mm and a thickness of 2 mm was obtained. This material was cut to a predetermined tip seal length (60 mm) of a scroll compressor, and the end was processed into a predetermined R shape. After putting the cut rod-shaped tip seal material into a container with the same shape as the spiral groove and heating it at 250 ° C for 3 hours,
By taking it out and allowing it to cool, a spiral tip seal was obtained.

Example 5 On the other hand, a ram extrusion die (Uchinori dimension: outer diameter 70 mm,
A cylindrical molded body was obtained in the same manner as in Example 1, except that the inner diameter was 65 mm and the overall length was 1000 mm. The cylindrical shaped body was spirally cut from one end face to the other end face. The spiral body was processed in the same manner as in Example 1 to obtain a spiral tip seal.

Example 6 A ring-shaped member was formed by cutting the cylindrical molded body obtained in Example 5 into a slice, and this ring-shaped member was cut at one place in the diameter direction to obtain a C-shaped body. Was. The C-shaped body was processed in the same manner as in Example 1 to obtain a spiral tip seal.

Comparative Example 1 Using the same raw materials as in Example 1, this mixed material was placed in a predetermined mold (dimensions: outer dimensions 330 mm, inner diameter 100 mm, height 330).
mm), pre-molded with a pressure of 50 MPa,
The obtained preform was taken out of the mold and heated at 360 ° C. for 3 hours to obtain a cylindrical shape. The cylindrical molded body was skived with a lathe to form a sheet material having a thickness of 2 mm.
Five sheets of this 2 mm thick sheet material were stacked and punched into a chip seal shape with a punch to obtain a spiral chip seal.

[0034]

[Table 1]

The chip seals formed by the manufacturing methods according to Examples 1 to 6 have a yield rate of 70 to 80, respectively.
%, And the dimensional accuracy between the single elements could be formed without variation. On the other hand, the chip seals formed by the manufacturing method according to Comparative Example 1 had a yield rate of 40 to 50%, respectively, and the dimensional accuracy among the individual pieces was notable.

[0036]

According to the present invention, a resin composition containing a fluororesin as a main component is extruded into a cylindrical molded body by an extrusion molding method, and a tip seal for a scroll compressor is manufactured by the above method. Even if a material containing a fluorine resin as a main component is used, a tip seal for a scroll compressor can be manufactured with high yield. Further, the obtained chip seal is excellent in dimensional accuracy between the single pieces.

Further, since the fluororesin is at least one resin selected from the group consisting of ethylene tetrafluoride resin and modified tetrafluoroethylene resin, a tip seal for a scroll compressor having excellent sliding characteristics even in a dry atmosphere. Can be manufactured.

[Brief description of the drawings]

FIG. 1 is a view showing a manufacturing process of a chip seal.

FIG. 2 is a view showing a manufacturing process of a chip seal.

FIG. 3 is a view showing a manufacturing process of a chip seal.

FIG. 4 is a perspective view of a tip seal.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Cylindrical molding 2a Spiral 2b Spiral 2c C-shaped

Claims (4)

[Claims] A step of extruding a resin composition containing a fluororesin as a main component into a cylindrical molded body by an extrusion molding method; a step of cutting the cylindrical molded body into a ring to form a ring-shaped member; A step of spirally cutting the ring-shaped member from the outer peripheral surface toward the inner peripheral surface. 2. A step of molding a resin composition containing a fluororesin as a main component into a cylindrical molded body by an extrusion molding method, and spirally cutting from one end face of the cylindrical molded body to another end face. A method of manufacturing a tip seal for a scroll compressor. 3. A step of extruding a resin composition containing a fluororesin as a main component into a cylindrical molded article by an extrusion molding method; and a step of cutting the cylindrical molded article into a ring to form a ring-shaped member; Cutting the ring-shaped member at one place in the diameter direction to form a C-shaped body. 4. The method according to claim 1, wherein said fluororesin is at least one resin selected from ethylene tetrafluoride resin and modified tetrafluoroethylene resin. A method for manufacturing a tip seal for a scroll compressor.