JPH11351161A - Scroll compressor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To increase abrasion resistance so as to allow long-term use by forming a tip seal for a scroll from a material containing PTFE as a principal constituent and applying a coating containing PTFE-PAI-MoS2 substance as a main principal constituent onto a mirror finished surface at least in a mating part sliding on the tip seal. SOLUTION: In a scroll compressor, a tip seal insertion groove formed in a spiral shape substantially is formed in the position facing a mirror finished surface part in a mating side scroll member in each of a rotary scroll member and a fixed scroll member, and in these grooves, a tip seal is mounted so as to prevent gas leakage from the high pressure side to the lower pressure side. The tip seal member is formed of a material in which PTFE is contained as a principal constituent, an inorganic substance such as carbon fiber and glass fiber is added, and polyimice is mixed as filler for improving thermal resistance. On the other hand, on the scroll mirror finished surface, a coating containing a PTFE-PAI-MoS2 substance as a principal constituent is applied after treatment with hard anodized aluminum is applied.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a scroll compressor used for supplying compressed gas,
In particular, the present invention relates to a dry scroll compressor provided with a tip seal for preventing leakage of compressed gas.

[0002]

2. Description of the Related Art Tip seals for scroll compressors are:
During prolonged operation, it wears due to the lapping head that slides in contact, reducing the thickness of the tip seal. Therefore, in order to maintain the reliability of the tip seal even during long-term compressor operation, it is necessary that the tip seal extends or floats in the direction of the facing head plate, but basically the wear resistance of the tip seal is extremely good. Something is a premise and important.

[0003] As a known technique relating to a tip seal for a scroll compressor devised to solve the above problem, for example, there is the following.

Japanese Patent Publication No. Sho 63-32991 discloses a method of forming a hardened layer on the entire surface of a scroll and coating a material having a familiar property over the entire surface of the scroll. Although disclosed, the purpose of this case is to prevent leakage and galling in the radial clearance and axial clearance directions between the scrolls.

[0005] Japanese Patent Application Laid-Open No. HEI 3-11101 discloses a chip seal according to this known technique, in which a fine notch is obliquely displaced with respect to the surface of the chip seal and the compressor operates to increase the pressure around the chip seal. In addition, the high pressure gas intrudes into the notch to form the notch, thereby causing the chip seal to float and improving the sealing performance.

[0006] Japanese Patent Application Laid-Open No. 62-113882 discloses a seal member made of a material obtained by adding a fluorine resin powder such as PFA which can be spray-molded to an ethylene tetrafluoride resin containing an organic filler.

[0007]

However, in the case of the scroll compressor using the tip seal for leakage in the axial clearance direction of the reference 1, the coating is applied to the inner surface of the end plate where the tip of the tip seal slides. This also causes a problem in terms of wear of the tip seal.

That is, when coating is performed on the inner surface of the end plate of the sliding surface with the chip seal, the heat insulation of the compression heat by the coating increases, the temperature of the sliding surface of the chip seal increases, and if the resin component is PTFE alone, Wear of the tip seal increases early.

[0009] In this regard, Reference 1 does not take active consideration for the abrasion resistance and durability of the coating at a high temperature of, for example, 200 ° C. or higher.

Next, the above-mentioned known technology has the following problems.

In the prior art, since the notch cut obliquely to the surface of the chip seal is small, the floating amount (elongation amount) in the direction of the lap head plate is small. Therefore, it is difficult to make the tip seal float by compensating for the wear caused by long-term use, and it is difficult to improve the reliability for long-term use.

[0012] Further, because of the structure in which pressure is introduced into the oblique cut to float the entire tip seal, the introduced pressure cannot all act in the floating direction. For example, a part of the introduced pressure is required to open the cut. Since it acts downward, the pressure is not used effectively for levitation. Therefore, as a result, the ambient pressure required for floating (elongation) needs to be large to some extent, and it is practically difficult to apply the chip pressure to the outer peripheral portion of the scroll where the atmospheric pressure is not structurally high.

Further, the above-mentioned known technology has the following problems.

That is, the seal member is formed of a material obtained by adding a fluorine resin powder (PFA) which can be spray-molded to tetrafluoroethylene resin containing an organic filler.

However, when PFA is added, the abrasion resistance is reduced accordingly. Therefore, as a tip seal expected to have a long-term wear resistance of at least two to three years, although it is evaluated that it can be spray-molded, it is a practical problem if long-term durability is lost.

An object of the present invention is to solve the above-mentioned problems of the conventional tip seal. Its purpose is to have good abrasion resistance even for long-term use, maintain sealing performance and high reliability.Also, even when the peripheral pressure of the tip seal is small, it can float and seal reliably, making it more difficult to manufacture. Accordingly, it is an object of the present invention to provide a compressor that is suitable for mass production and that can prevent a decrease in compression efficiency over a long period of several years.

[0017]

As is clear from the typical known art of the reference, the point that only the tip seal or the scroll end plate portion is targeted. The conventional development is to secure the long-term durability of the tip seal. It was a one-sided view.

[0018] However, in the real problem, simply solving one problem (as if by a muffler) raises another problem this time.

That is, there is a limit to whether the tip seal can be used for a long time without replacement in a dry scroll compressor, as described in the reference.

Because wear is a phenomenon that occurs due to the presence of two objects that slide with respect to each other, in this case, the properties of the scroll end plate surface as the mating member with which the tip seal contacts and slides are different. It is a problem. And it became clear that even with the tip seal of the same component, the abrasion resistance is greatly different depending on the properties of the scroll head surface.

Similarly, the coating of the familiar material on the scroll surface in the reference is effective or ineffective depending on the material and composition of the tip seal.

Further, as for the shape and structure of the tip seal as in the reference, the shape and structure of this example may not exhibit the function of the tip seal depending on the material of the tip seal material. For example, in the reference, if the material is not a soft material, the preset cut does not open and does not bring about a sealing effect.

According to the present invention, in order to maintain a high performance and a high durability for a long time in a dry scroll compressor, only one specification of one of the components, for example, only a component of a tip seal is specified. Was considered to be extremely inadequate.

That is, PTF is used as a chip sealing material.
E is a main component, and an inorganic substance such as carbon fiber or glass fiber is added to improve mechanical properties, and a polyimide or the like is further compounded as a filler to improve heat resistance. The seal shape is based on a general shape, but is preferably a combination shape of two rectangular divisions.

Next, the surface of the scroll head plate is subjected to a hard alumite treatment and then to a coating mainly composed of PTFE-PAI-MoS ₂ system.

That is, this can significantly reduce the wear of the tip seal. In this component, PAI has an imide group as a component element,
It also has thermosetting properties. That is, the crosslinking reaction is promoted together with the heating, and when heated to a high temperature up to about 350 ° C., the strength is further improved. Therefore, in the scroll compressor, the film strength improves near the air discharge port exposed to a high temperature (around 250 ° C.). Therefore, there is no problem that is feared in the references, and it is rather an advantage.

Generally, alumite and P as mating materials
The sliding wear of the TFE system greatly differs depending on whether or not the PTFE component is transferred to the surface of the mating material. Hereinafter, this will be described with reference to examples.

[0028]

[Embodiment 1] In other words, as shown in FIG. 1, PTFE is transferred to the alumite surface so that the sliding range is smoothed. it is obvious. When PTFE is not transferred as the tip seal material, the wear increases linearly as shown in FIG. 3, and the durability of the tip seal is extremely short.

However, when the transfer is sufficiently performed, the wear curve is steep as the initial wear for a certain time (t in the figure) until the transfer is completed as shown in FIG. Becomes a steady wear state, and wear progresses very little.

Therefore, the endurance time of the tip seal is extremely long, and it can withstand several years of continuous use.

[Embodiment 2] Although the above theory is generally correct, the problem is whether or not such transfer is performed in an actual machine. In the case of an actual machine, almost no transfer is made.

In particular, the transfer amount is zero in the intermediate portion and the central portion where transfer is desired. That is, in the case of the actual machine, a differential pressure is generated in the process of compressing the air, thereby generating a strong air flow. The abrasion powder generated for that purpose is blown off by the compressed air before being transferred to the alumite surface of the scroll head plate, and is discharged to the outside from the discharge port.

[Embodiment 3] In order to clarify this point by elementary experiments, the result of the experiment is shown in FIG. As shown in FIG. 4, the transfer of PTFE is zero in the case of () with air discharge, and the transfer proceeds rapidly after the start of the test in the case of () without discharge, and is almost saturated at time t ′. It became a state.
The time t in FIG. 1 and t ′ in FIG. 4 have a substantially uniform relationship of t ≒ t ′ in time.

[Embodiment 4] From the previous embodiment, the rapid progress of abrasion in the actual machine presumes that there is no transfer of PTFE. FIG. 5 shows the results of an experiment conducted to examine the effect of a PTFE precoat in place of.

From this, it can be seen that the effect of the air blowing and the PTFE pre-coating () on the mating material is extremely large as compared with the air blowing and no mating material PTFE pre-coating ().

Note that the above description is based on no air blowing-PTF
Compared with E transfer (FIG. 3), it is excellent in the following points.

That is, FIG. 3 shows that the wear of the PTFE progresses rapidly until the start of steady wear, but in the case of FIG. Abrasion resistance is easy.

[Embodiment 5] Next, FIG. 7 shows the durability test results obtained by applying the results of the element tests to an actual machine. As described above, even when the chip seal is worn for a long period of time, the wear of the tip seal is slight. By calculating backward from this curve, the usable life of the tip seal when the PTFE coating is applied to the scroll surface is several minutes. Was estimated to be years.

[0039]

According to the present invention, the wear of the tip seal is extremely small with time and the performance is exhibited for several years. Therefore, the reliability of the dry scroll compressor provided with the tip seal is extremely high, and the dry scroll compressor provided with the tip seal has a long life. Withstand several years of continuous use.

[Brief description of the drawings]

FIGS. 1 (1) and (2) are a plan view of a wear test piece disk surface and a characteristic diagram showing transfer of PTFE to the disk surface.

FIG. 2 is a characteristic diagram showing a change in roughness of a mating alumite surface due to PTFE transfer.

FIG. 3 is a characteristic diagram showing wear of a chip sealing material in an element test.

FIGS. 4A and 4B are a cross-sectional view of an element testing machine and a characteristic diagram showing a state of transfer of PTFE to a disk in an element test.

FIG. 5 is a characteristic diagram showing the effect of the PTFE coating on the wear depth of the chip seal.

FIG. 6 is a characteristic diagram showing the surface roughness of a mating material after an air blowing wear test.

FIG. 7 is a characteristic diagram showing a comparison of wear characteristics between an actual machine and an element test.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Yoshishige Endo 502 Kandachi-cho, Tsuchiura-shi, Ibaraki Pref. Machinery Research Laboratory, Hitachi, Ltd. Inside the Hitachi Machinery Research Laboratory (72) Inventor Shigeru Machida 502 Kandachicho, Tsuchiura-shi, Ibaraki Prefecture Inside the Hitachi Machinery Research Laboratory Co., Ltd. Within the business division

Claims (6)

[Claims] An orbiting scroll member and a fixed scroll member having a substantially spiral shape; a portion of the orbiting scroll member facing the end plate portion of the fixed scroll; and a portion of the fixed scroll member facing the end plate portion of the orbiting scroll. A part to be inserted, a chip seal insertion groove formed along the substantially spiral direction, and a chip seal mounted on the chip seal insertion groove to prevent gas leakage from the high pressure side to the low pressure side. In the scroll compressor provided, the tip seal of the scroll is mainly composed of PTFE, and a coating mainly composed of PTFE-PAI-MoS ₂ is applied to at least the surface of the end plate sliding on the tip seal. A scroll compressor characterized by the following. 2. The swirl direction according to claim 1, wherein a plurality of pressure chambers are provided in the substantially spiral direction of the tip seal, the plurality of pressure chambers being substantially prevented from communicating with each other, and the respective pressure chambers are provided. Wherein the high-pressure side pressure is introduced into the pressure chamber. 3. The scroll compressor according to claim 2, wherein said tip seal comprises a lower member mounted on a bottom side of said tip seal insertion groove, and an upper member mounted on said lower member. Wherein the plurality of pressure chambers are formed between the lower member and the upper member. 4. The scroll compressor according to claim 3, wherein substantially rectangular irregularities are formed on the lower surface of the upper member and the upper surface of the lower member, respectively, and these are substantially fitted to each other. A scroll compressor, wherein the plurality of pressure chambers are formed in a portion. 5. The chip seal according to claim 1, wherein:
PTFE as a main component, and one or two of powder or fiber such as MoS ₂ , C braid, graphite, BN, etc.
A scroll compressor characterized in that at least one of them is added as a filler, and the tip seal is provided. 6. The method of claim 1, wherein said coating is P
When TFE is the first principal component, PAI, Mo
The addition of S ₂ , graphite, C braiding, or the like as a filler, and the use of PAI as a main component are based on PTFE, Mo.
A scroll compressor characterized by adding S ₂ , graphite, carbon fiber or the like as a filler, and applying at least one of the above-mentioned coatings to at least a mirror plate surface.