JPS61294180A - Scroll type compressor - Google Patents

Abstract

PURPOSE:To aim at improvement in the productivity and reliability by coating the metallic base material which forms the teeth of both or either one of a fixed scroll and an oscillating scroll by the use of a covering material consisting of inorganic material-filled thermosetting resin. CONSTITUTION:A fixed scroll 1, in which laminar teeth are formed spirally, and an oscillating scroll 2, in which teeth of the same shape as the above are formed, are closely engaged and facing with each other and accordingly, oscillation of the oscillating scroll 2 causes a gas to be compressed and discharged. In the above, the metallic base materials 1a, 20 which form the teeth of both or either one of each scroll 1, 2, is coated with covering materials 1a, 2a consisting of inorganic material filled thermosetting resin. In this case, for the covering material, at least 50% inorganic filler, such as quartz glass, fused quartz, is combined, by volume and thermosetting resin having a linear expansion coefficient of not more than 3.0X10<-5> is used.

Description

Detailed Description of the Invention [Field of Application of the Invention] The present invention relates to a scroll compressor used for refrigeration or air conditioning, and particularly relates to a scroll compressor having a scroll configuration that is advantageous for improving productivity and reliability. It is something.

[Background of the invention]

Figure 2 1. FIG. 3 shows a schematic cross-sectional view of the main parts and an explanatory diagram of the operation of a conventional scroll compressor. In the figure, a fixed scroll 1 having plate-shaped teeth formed in a spiral shape and an oscillating scroll 2 having teeth of the same shape as the fixed scroll 1 are fitted facing each other. Then, as the oscillating scroll rotates 20 times, the teeth make an oscillating movement and the fixed scroll 1
This is an operating mechanism in which the volume of the compression chamber formed between the teeth of the oscillating scroll 2 is sequentially reduced and moved to the center, and compressed gas is discharged from the compressed gas discharge port 3 in the center.

FIG. 4 shows an enlarged sectional view of the teeth of the fixed scroll 1 and the orbiting scroll 2. As can be seen from this figure, when the dimensional accuracy of the teeth of the fixed scroll 1 and the orbiting scroll 2 is poor, the compressed gas leakage and reduce the compression ratio, and tooth galling can cause damage to the teeth, so very high dimensional accuracy is required, especially good surface roughness of the contact surface, surface angle to plywood, and wear resistance. etc. are required. Furthermore, in order to obtain a high compression ratio, it is desirable that the teeth have high fatigue strength. Therefore, conventional scrolls have the drawback that they are manufactured using a large number of man-hours and process time in order to finish the expensive metal base material with excellent wear resistance and fatigue strength to a high precision on the μm order through precision machining. there were.

In order to improve this drawback, it has been proposed to form precision-molded resin layers on the opposing surfaces of the fixed scroll and the oscillating scroll member, as described in Japanese Patent Application Laid-Open No. 58-91388. There is. A cross-sectional view of this scroll and a conceptual diagram of the manufacturing method are shown in FIGS. 4 and 5. This is a proposal to reduce the number of high-precision metal finishing processes by forming a high-precision resin layer. However, this publication only mentions that thermoplastic resin is used as the resin material, and it has the high dimensional accuracy, abrasion resistance, and
There were no proposals for specific materials or structures to ensure flat fatigue strength or adhesion to metal base materials, and there was a lack of consideration for reliability.

In general, scroll compressors are not only operated under high pressure and high temperature conditions, but also use a mixed gas of fluorocarbon gas and machine oil as the gas. Therefore, JP-A-58-9
With only the content disclosed in Publication No. 1388, it is not possible to ensure not only the initial dimensional accuracy of the scroll teeth, but also the dimensional accuracy during scroll operation, wear resistance, and adhesion to the metal base material, and it is not practical. cannot be changed.

[Purpose of the invention]

An object of the present invention is to provide a coating material and a scroll configuration for a scroll member that provide high dimensional accuracy, wear resistance, high fatigue strength, oil resistance, and high adhesive strength with the metal base material, thereby achieving high reliability. It is an object of the present invention to provide a scroll compressor that has excellent productivity.

[Summary of the invention]

The present invention provides stress conditions during scroll operation,
In other words, it maintains high dimensional accuracy even under extremely harsh conditions such as high temperature/high pressure/temperature cycles and exposure to a mixture of fluorocarbon gas and machine oil, has excellent wear resistance, and has durable mechanical strength as a scroll tooth. This was based on the recognition and experimental results that the scroll structure, which requires excellent performance, cannot be achieved by simply combining a common thermoplastic resin and a scroll structure designed for conventional machining. It is. That is, amorphous resins such as polycarbonate, which have relatively excellent moldability and dimensional accuracy among thermoplastic resins, have poor oil resistance and cannot withstand stress during scroll operation. On the other hand, among thermoplastic resins, crystalline resins such as polybutylene terephthalate and polyether sulfon resin, which have relatively excellent oil resistance and heat resistance, have a large molding shrinkage rate, making it difficult to ensure the dimensional accuracy of scroll teeth. Furthermore, these thermoplastic resins have low adhesive strength with the metal base material, and cannot withstand the thermal stress caused by the thermal cycle that occurs when compressing gas during scroll operation.
After a very short period of operation, the adhesive surface peeled off, the scroll teeth were damaged, and the compression ratio suddenly decreased.

The inventors of the present application have improved the adhesive strength and oil resistance with the metal base material,
The base resin is a thermosetting resin such as epoxy resin or bismaleimide/triazine resin, which has excellent resistance to fluorocarbon gas, and is highly filled with inorganic filler such as quartz glass or fused silica to reduce thermal stress during thermal cycles. By developing a covering molding material for scroll members and designing the shape and surface shape of the scroll base metal itself to improve adhesive strength, we have discovered that it is possible to create a highly reliable metal/plastic composite scroll for the first time. I found it.

As the base material for the fixed scroll and the oscillating scroll in the present invention, a material that can be cast, such as cast iron or aluminum die-casting, or a material that can be hot forged, and has strong fatigue strength and high rigidity, is used. The shape precision of the base material and scroll teeth formed in this way may be low. However, in order to improve the adhesive strength with the coating resin material, the surface roughness of the base material is adjusted to Hmax =
It is desirable that the thickness be in the range of 1 to 15 μm.

Further, when molding the coated resin material, the draft angle is required to be 2° or more in order to reduce the stress when the mold is released from the mold. Since the dimensional accuracy of the scroll teeth cannot be ensured due to changes in the thickness of the coating resin film, the taper angle of the base material itself is also set to approximately the same angle. Furthermore, since the breakage of the coating material occurs when the thermal stress generated during thermal cycles is concentrated at the corner, the corner radius R of the corner of the metal base material and the coating resin surface is 0.5 to 2 nnns.
Set to the same value in the range. In this way, even if the teeth of the fixed scroll and the oscillating scroll are tapered and have a corner radius R, if the shapes of the teeth of both are designed to be the same, they will not buffer each other and the dimensional accuracy of the coating resin material, which will be described later, will be maintained. It was found that if this could be ensured, a high compression ratio could be obtained.

In order to achieve the above objectives, the design of the coating resin material is most important. In other words, as mentioned earlier, various thermoplastic resins were considered, but the adhesive surface peeled off after only a short period of scroll operation, resulting in damage to the scroll teeth or a sudden drop in the compression ratio. . The present invention
The structure of this coating resin is the main focus, and preferred coating resin materials will be explained in detail in the description of Examples.

Figure 1 (α) is a cross-sectional view of a scroll made of composite metal and plastic for a scroll compressor according to the present invention;
+ is an enlarged view of the tooth portion, 1 is a fixed scroll, 2 is an oscillating scroll, 1゛α, 1b is a resin-coated bottom plate of the fixed scroll 1 and a resin-coated portion of the teeth, 2α
, 2h indicate the resin-coated bottom plate and resin-coated portions of the teeth of the oscillating scroll 2, respectively.

[Embodiments of the invention]

Next, embodiments of the present invention will be described in detail. In addition,
The following embodiments are all based on the base material shape and scroll tooth shape described above.

Example 1 Cresol novolac epoxy resin (20% by weight) was used as the base resin, and phenol (10% by weight) was used as the curing agent.
), quartz glass powder (70% by weight, 50% by volume) as a filler, and a semiconductor encapsulation resin containing a small amount of a curing accelerator, a silane coupling agent, and an internal mold release agent. Insert and transfer mold. At this time, the linear expansion coefficient of this resin is 2. ! 5X10-'
.

The secondary dislocation temperature T was 145° C., and the adhesive strength with the metal base was measured to be 100 Kg/− (room temperature) or more.

The dimensional accuracy of the molded scroll teeth is 1 with respect to the reference point.
An extremely high accuracy of 3 μm was obtained.

As a result of assembling the fixed scroll and the oscillating scroll obtained in this way and conducting an actual machine test, it was found that even after a predetermined acceleration test, the scroll teeth were not easily damaged and the compression ratio did not suddenly decrease. The coating resin surface of the contact area between the L or L1 fixed scroll and the oscillating scroll was whitened, and it was observed that the wear was progressing. When we measured the coefficient of static friction between the two resins, we found that it was in the range of 04 to 045.

Example 2 Based on the epoxy resin composition used in Example 1, graphite powder and solipden disulfide ('oSa) were added.
An epoxy resin composition containing 10% by weight of the powder mixture was prepared and molded in the same manner as in Example 1. As a result, the linear expansion coefficient is 2.5 (0-1), and T is 145
Example 1
It was almost the same as in the case of , but the coefficient of static friction was 0.
It was measured as 3, which was a significant improvement.

As a result of assembling the fixed scroll and the oscillating scroll obtained in this way and conducting an actual machine test, not only was there no damage to the scroll teeth even after the prescribed acceleration test, but whitening of the contact area between the bottom of the fixed scroll and the oscillating scroll was observed. First, good dimensional accuracy was maintained, and no decrease in compression ratio was observed during the accelerated test.

Example 6 Instead of the epoxy resin used in Examples 1 and 2, bismaleimide triazine resin (BT resin, 30% by weight) was used as the base resin, fused silica (60% by weight) as the filler, and a solid lubricant. As a mixture of graphite powder and molybdenum disulfide (MoSt) (10% by weight)
) was prepared and molded in the same manner as in Example 1. As a result, the coefficient of linear expansion is 2. lX1
0-1', Tg is 190℃, adhesive strength with metal base material is 20
Measured to be 0 Kf/cd (room temperature) or higher, especially 150
The fact that the adhesive strength with metal at 0.degree. C. was measured to be 100 KV/- or more suggested that the durability would be further improved than in the case of epoxy resin. The static friction coefficient was also 03, which was different from Example 2.

As a result of assembling the fixed scroll and the oscillating scroll obtained in this way and conducting an actual machine test, no damage to the scroll or whitening of the contact area was observed. The ratio was found to be stable over a long period of time.

A thermoelastic stress analysis was conducted using the physical property values of the resin compositions used in Examples 1 to 3 described above. The result was as shown in Figure 1 (Al).

It was verified that the base metal and coated resin shape of the present invention had the least concentrated stress. Furthermore, it has been found that the linear thermal expansion coefficient of the resin is 3.0×10 −1 or less, and the higher the Tg, the more desirable it is from the relationship between the thermal stress and the breaking stress of the resin. In addition, although the molding shrinkage rate of the resin used in the example is as small as 0.5 to 0.8 inches, when the shape of the metal base material is straightened, the dimensional accuracy of the root of the tooth deteriorates, and the predetermined target accuracy of 5 μm I was able to analyze things that cannot be summarized below.

In the above example, an example was explained in which a specific base resin was used, but the base resin used in the present invention is not limited to that used in the example, and has excellent oil resistance and fluorocarbon gas resistance, and has excellent adhesion to metal. It is a thermosetting resin with excellent
Further, any resin may be used as long as it can achieve the linear expansion coefficient and molding shrinkage rate shown here by blending inorganic fins, and desirably can obtain a high Tg. Furthermore, the molding method is not limited to the transfer molding method.

Here, some thermosetting resins that may be taken up in implementing the present invention will be explained. First, PEEK
(polyetheretherketone), aromatic polyamide,
Among thermoplastic resins such as polyamide and imide, there are resins that have excellent heat resistance and oil resistance, but at present the resin shown in the example does not have excellent moldability and is not being considered. If moldability is improved and physical properties such as linear expansion coefficient equivalent to those shown in the examples can be satisfied, there is a possibility that these thermoplastic resins can be used. In addition, there is a thermosetting resin based on unsaturated polyester that is suitable for precision molding and is known as BMC (bulk mold compound), but it does not have excellent adhesion to metals and is resistant to moisture and high temperatures. There is a high possibility that it will be hydrolyzed, so it has not been considered. However, if their physical properties are improved,
There is a possibility of being hired.

Moreover, pps (polyphenylene sulfide) resin highly filled with inorganic fins has the physical properties closest to that of the resin of the example among thermoplastic resins. Although it is a crystalline resin and has poor dimensional accuracy, molding conditions are currently being considered and the possibility of realization is highest.

According to the present invention, as a result of highly filling the coating resin material with inorganic filler, high molding accuracy on the μ-order order can be obtained, and the base resin has excellent oil resistance, fluorocarbon gas resistance, and high adhesive strength with metal. , the dimensional accuracy and strength durability of the scroll teeth are improved. Furthermore, as a result of incorporating a solid lubricant into the coating material, the coefficient of static friction was reduced, causing almost no wear, reducing the driving force of the scroll, and virtually eliminating changes in the compression ratio over time. moreover,
By making the shape of the metal matrix and the shape of the coating resin advantageous for ensuring dimensional accuracy without stress concentration, it is possible to realize a metal-plastic composite scroll with excellent durability and no breakage of the coating resin. As a result of discovering the above-mentioned highly durable resin composition and scroll structure, the number of processes is reduced to 1 compared to conventional precision-cut scrolls by machining.
/3, the process time can be reduced to 1/2, and equipment investment efficiency can be significantly improved.

〔Effect of the invention〕

As explained in detail above, according to the present invention, it is possible to realize a scroll compressor that has high reliability and excellent productivity.

[Brief explanation of drawings]

Figure 1) is a cross-sectional view of a scroll made of composite metal and plastic for a scroll compressor according to the present invention;
2 is a schematic sectional view of the main parts of a conventional scroll compressor, 3 is an explanatory diagram of its operation, and 4 is an enlarged view of the tooth portion.
The figure is an enlarged sectional view of the teeth of the fixed scroll and the oscillating scroll of the scroll compressor, FIG. 5 is a sectional view of a conventionally proposed metal/plastic composite scroll, and
The figure is a conceptual diagram showing the manufacturing method. Explanation of symbols 1...Fixed scroll 1a...Resin-coated bottom plate 1A of fixed scroll...Resin-coated portions of teeth of fixed scroll 2...Essential scroll 2a...Resin-coated bottom plate No. 1 of oscillating scroll 2 Engraved on Figure 1 4 Kasumi L Figure 5 Figure G

Claims (4)

[Claims] (1) A fixed scroll having plate-shaped teeth formed in a spiral shape and an oscillating scroll having teeth of the same shape as the teeth of this fixed scroll are fitted facing each other, and the oscillating movement of the oscillating scroll A scroll compressor for compressing and discharging gas, wherein the metal base forming the teeth of both or one of the fixed scroll and the oscillating scroll is coated with a coating material made of a thermosetting resin blended with an inorganic filler. A scroll compressor characterized in that it is covered with a scroll compressor. (2) A thermosetting resin containing at least 50% by volume of inorganic filler such as quartz glass or fused silica and having a coefficient of linear expansion of 3.0 x 10^-^5 or less is used as the coating material. A scroll compressor according to claim 1. (3) The thermosetting resin used for the coating material is a thermosetting resin having a secondary transition temperature (Tg) of 120°C or higher. scroll compressor. (4) The coating material used is one or a mixture of solid lubricants such as tetrafluoroethylene polymer, molybdenum disulfide, and graphite. Scroll compressor according to any one of item 3.