JP2001323882A - Unit device for scroll fluid machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To outstandingly improve an abrasion-resistance at a higher temperature by investigating a composition of a tip seal and to enhance a reliability of an oil free scroll fluid machine and a system thereof equipped with this. SOLUTION: A tip seal containing PAI as a main component in which MoS2, SB2O3, C (graphite) and PTFE are formulated as fillers is auxiliarily provided on an oil free scroll fluid machine. Thereby, since an abrasion speed of the tip seal can be outstandingly reduced, the oil free type scroll fluid machine with a high performance and a high reliability can be provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a orbiting positive displacement compressor for compressing gas while reducing the volume of a compression working chamber, and more particularly to a crescent-shaped orbiting scroll and a fixed scroll member. The present invention relates to an oil-free scroll fluid machine in which a crescent-shaped compression chamber is formed, and the crescent-shaped compression chamber compresses gas while reducing the volume by the orbiting motion of the orbiting scroll.

[0002]

2. Description of the Related Art As is conventionally known, a scroll compressor is provided with an orbiting wrap formed upright in a spiral shape with a continuous curve such as an involute curve on an end plate, and both rotating and fixed scroll members are engaged with each other. In addition, one of the scroll members is rotated relative to the other scroll member so as not to rotate with respect to the other scroll member, so that the one of the scroll members is rotated relatively to compress the gas from the outer periphery to the center of the scroll member. Among them, the oil-type scroll compressor has a lubricating action and a cooling action, so that there is almost no difference between the temperature of the gas inlet and the temperature of the gas outlet. However, in the oil-free scroll compressor to which the present invention is directed, since the air temperature at the end of compression is generally substantially determined by an adiabatic compression change, the air temperature at the end of compression is more than the rise in the compression start temperature. The problem is that the temperature rises to a significantly higher temperature level.

Further, when the discharge pressure is further increased or the compressor capacity is further increased, the compression end temperature further increases.

[0004] In particular, when the compression end temperature is high, the scroll member itself becomes high in temperature, but is compressed along the spiral to the central part, so that the central part of the scroll has the highest pressure. The part gets hottest. Since the temperature distribution substantially corresponds to the pressure distribution as described above, the amount of thermal deformation of the scroll member is not constant. For this reason, the thermal expansion in the height direction of the scroll wrap is not uniform, and the gap between the scroll wrap tip surface and the lap end plate surface is not uniform. Therefore, Tokuho 6
As shown in the prior art such as Japanese Patent No. 31624, it is necessary to attach a “tip seal” as a sealing component at the tip of the wrap in order to prevent leakage of compressed gas and maintain high compression efficiency. become. When driving,
Relative slippage occurs between the tip seal and the surface of the lap head plate, which causes a problem of wear of the tip seal, which is softer than the wrap.

[0005] That is, it is extremely important to keep the wear of the tip seal at zero or extremely small in the long term in order to improve the performance of the oil-free scroll compressor and maintain long-term reliability. Conventionally, PTFE resin has been mainly used as a material for the tip seal. The degree of abrasion largely depends on the relative speed and pressing force on the sliding surface between the lap head surface and the tip seal, and the ambient temperature. The amount of wear of the tip seal further varies depending on the condition of the sliding surface and the like, but the amount of wear in the compressor is characterized by a large change particularly depending on the ambient temperature. That is, since the temperature near the air suction port, which is the compression start point, is kept at a temperature not so high from room temperature, the influence of the temperature on the wear amount is small.

However, as described above, during operation of the compressor, the temperature at the center of the scroll becomes extremely high, so that the amount of wear of the tip seal increases at the center, and high-pressure air leaks to reduce the compressor performance. Lower. in this way,
When the wear of the tip seal is viewed in the direction along the spiral, the product partially increases due to the relationship between the pressure difference and the temperature, but the effect of the temperature is the highest among them.

The tip seal slides on the lap mirror surface of the counterpart scroll, and the temperature of the mirror surface is also a major factor influencing the amount of wear. The temperature of the head surface is generally lower than the temperature of the compressed air, but is characterized by a very strong correlation with the wear amount of the tip seal because it directly forms a sliding surface.

[0008] A new composition of a tip seal for an oil-free scroll compressor is disclosed in Japanese Patent Application Laid-Open No. 10-80332. According to the present invention, the fluorocarbon polymer 10 is added to 35 to 80% by weight of the polyphenylene sulfide resin.
A means is used in which about 35% by weight, 5 to 15% by weight of pitch-based carbon fibers, and 5 to 15% by weight of an organic powder which maintains a solid state at the melt molding temperature of the polyphenylene sulfide resin are added. That is, an object of the present invention is to provide a chip seal material which has excellent mechanical strength, does not damage a mating material, and is easy to perform abrasion resistance during sliding and precise injection molding.

Since the present invention uses a polyphenylene sulfide resin as a base resin, heat resistance, mechanical strength, abrasion resistance during sliding, and the like are improved as compared with a conventional chip seal containing a PTFE resin as a main component. That is true. However, the above-described technology disclosed in Japanese Patent Application Laid-Open Publication No. H11-157556 discloses an oil-free scroll compressor that has a high-pressure specification in which the discharge pressure is 0.9 Mpa or more, or a compressor in which the compressor capacity is 7.5 kW or more. It is not always suitable for large ones. In such a case, the amount of heat generated by the compression of the gas is extremely large, so that the discharge air temperature tends to be extremely high. This is because a general resin system containing PPS and the like softens with an increase in ambient temperature, resulting in severe wear. Therefore, it is not always possible to use PPS as a base resin. That is, even when a high-strength PPS is used as the base resin because of its excellent heat resistance, the softening gradually progresses with an increase in the temperature. Therefore, when the ambient temperature is high, such as 230 to 260 ° C. or higher, the softening / deterioration occurs. This is because the wear may progress and the long-term reliability may decrease.

[0010]

SUMMARY OF THE INVENTION An oil-free scroll compressor having a high-pressure specification in which the discharge pressure is 0.9 MPa or more, or a large-sized compressor in which the compressor capacity is nominally 7.5 kW or more. In this case, the discharge air temperature tends to be extremely high because the amount of heat generated by the compression of the gas is large. Accordingly, since the ambient temperature can be as high as, for example, higher than 230 to 260 ° C., the chip seal according to the conventional technique may be softened or deteriorated due to the high temperature, causing abrasion to progress and the long-term reliability to be reduced.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems, and to improve the characteristics such as hardness and abrasion resistance with an increase in temperature with respect to an oil-free scroll air compressor among scroll fluid machines. A large capacity (7.7 ° C) where the ambient temperature exceeds 230-260 ° C while ensuring a proper gap between the scroll wrap and the end plate and ensuring long-term reliability against wear of the tip seal. 5
kW to 11 kW or more), high pressure (discharge pressure of 0.9 Mpa or more), and high-performance oil-free scroll fluid machine with high and high performance.

[0012]

To achieve the above object, the present invention takes the following measures. That is, in the present invention, the main component is a polyamideimide resin (PAI) that maintains high strength even at a high temperature, and molybdenum disulfide (MoS ₂ ) and antimony trioxide (SB) are used.
₂ O ₃ ), graphite (C), and more preferably, to a chip seal to which polytetrafluoroethylene (PTFE) as a fluorocarbon polymer is added.

The details will be described below.

[0014]

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[0015]

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First, the polyamideimide resin (hereinafter abbreviated as PAI) used in the present invention is a synthetic resin represented by the structural formulas (Chemical Formula 1) and (Chemical Formula 2). 50% of this polymer is in a non-imidated or amic acid state, and upon application of heat, an imide ring is formed. This resin is a thermoplastic resin that can be injection molded and is obtained by reacting trimetic anhydride with an aromatic diamine. That is, the aromatic nucleus is composed of a polymer chain alternately connected by an amide bond and an imide bond. The tip seal according to the present invention containing a PAI resin as a main component is completely different from the known tip seal containing a PTFE, PPS, or the like as a main component, and has properties such as improved hardness and abrasion resistance when heated. It is a periodical chip seal. That is, the PAI resin, which is a main component of the chip seal of the present invention, has a chemical structure as shown in (Chemical formula 1) before heating, but is sufficiently heated at about 230 to 260 ° C. The structure changes, and the optimum molecular weight and physical properties are obtained accordingly. Therefore, PAI
The resin has a 'skeleton function' that maintains the shape of the tip seal of the present invention under severe wear conditions. The first principle of the present invention is that the PAI resin is used as the main component, and the hardness and strength are rapidly increased by high-temperature heating.

When PAI is used as the main component of the chip seal material, MOS ₂ is one of the leading lubricants, and the lubrication action under dry conditions is largely due to MOS ₂ . The molybdenum disulfide (MoS ₂ ) used in the present invention is a powder generally used as a solid lubricant, and has a particle size of 20%.
It is desirable that the diameter is within a micron. However, at high temperatures, oxidation with oxygen in the air is promoted, and 2MOS ₂ +
The reaction of 3O ₂ ⇒ 2MoO ₃ + 2S ₂ (gas) proceeds. As a result, the generated sulfur is oxidized to form SOx (gas), so that MoO ₃ has a reduced bonding force with the binder and is easily peeled. Further, even if MOO ₃ remains in the chip seal, the lubrication function of the chip seal deteriorates as a whole because MOO ₃ has low lubricity.

Oxidation of MOS ₂ progresses gradually from about 200 ° C. and rapidly progresses from around 300 ° C. In the present invention, SB ₂ O ₃ was added to prevent oxidation of MOS ₂ . FIG. 1 shows a schematic sectional view of the tip seal of the present invention. In FIG. 1, a is MoS ₂ , b is SB ₂ O ₃ , c is graphite, and d is a fluorocarbon polymer. SB ₂ O ₃ is interposed between the surface of the molded article and the inside of the MOS ₂ , and is more easily oxidized than the MOS ₂ , so that it selectively captures the invading oxygen and forms S ₂ O _3.
Since it becomes B ₂ O ₄ , this effectively prevents the oxidation of MOS ₂ , which is the second operational principle of the present invention. This antimony trioxide (SB ₂ O ₃ ) has a certain level of lubricity per se, and is generally used as a resin flame retardant.

Further, in the present invention, graphite is added as a solid lubricant having excellent heat resistance, and pitch-based graphite is used for this. This is because when pitch-based graphite is used, not only the heat resistance is good, but also the wear of the scroll main body as a sliding partner material can be reduced. In order to maintain good resin fluidity at the time of injection molding, the length of the graphite is desirably 20 μm or less. It is preferable to use a graphite whose surface is treated with a treating agent such as an epoxy resin, a polyamide resin, a polycarbonate resin, and a polyacetal resin, but is not limited to these.

As described above, according to the third aspect of the present invention, graphite, which is a solid lubricant having good heat resistance and hardly damages aluminum as a mating material, is used as one component of the chip sealing material. It is the principle of operation.

Next, the fluorocarbon polymer in the present invention is polytetrafluoroethylene, polytetrafluoroethylene-hexafluoropropylene copolymer,
It includes polytrichlorofluoroethylene, tetrafluoroethylene / perfluoroalkylvinyl ether copolymer, etc., and PTFE is particularly preferred. Also, PTFE having an average particle size of 20 μm is preferable. The role of the PTFE compound is that this is an effective organic solid lubricant,
The point is that the tip seal can be imparted with flexibility, thereby improving the sealing performance between the wrap and the seal groove side wall and preventing the leakage of high-pressure air. The fourth working principle of the present invention is to use PTFE as an organic solid lubricant as one of the components of the tip seal.

As described above, graphite and MOS, which are PAI as a main component and an inorganic solid lubricant as an auxiliary component,
₂ and a certain kind of solid lubricant, SB ₂ O ₃ having an action as an antioxidant for MOS ₂ , and a fluorocarbon polymer as an organic solid lubricant, preferably PTFE, the mixing ratio is as follows: It is. That is,
For 40 parts by weight of PAI, MOS ₂ is 5 to 7 parts by weight,
The content of SB ₂ O ₃ is ₃ to 5 parts by weight, the content of graphite is 0.7 to 0.9 parts by weight, and the content of the fluorocarbon polymer, preferably PTFE, is 6 to 8 parts by weight.

In the graphite, if the amount is less than 0.7 part by weight, the contribution to the improvement of heat resistance is insufficient, while if it exceeds 0.9 part by weight, the flowability of the molten resin is hindered. M
The OS _2, when a small amount of less than 5 parts by weight not good lubricity, the fluidity is a great amount exceeding 7 parts by weight conversely deteriorates. If the amount of the fluorocarbon polymer is less than 6 parts by weight, the contribution to the improvement in lubricity is insufficient, and
If the amount exceeds the weight part, the heat resistance decreases.

The mixing of these various materials can be carried out by known means such as dry blending using a Henschel mixer or melt mixing using a Brabender or an extruder.

[0025]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS (Example 1) First, the optimum compounding range of this chip sealing material was examined. PA as the main component
I was set to 40 parts by weight (constant), and the composition of other components was examined below. Judgment items of the experimental results were abrasion resistance, lubricity, the wear rate of the mating material, and injection moldability.
Next, it was determined by the following method.

Abrasion resistance--Evaluation of abrasion resistance was performed using an Amsula tester. In the test, two ring-shaped samples each having a diameter of 40 mm and a length of 10 mm were pressed at 10 kgf, and at 190 rpm,
The sliding was performed by generating 10% relative slip. For one of the samples, a hard aluminum material subjected to alumite treatment was used as a mating material. The results were excellent when the time until the generation of 2 mg of abrasion powder was 10 hours or more. The results were excellent when 1 hour or more and less than 10 hours were good, and when less than 1 hour was slightly poor.

Lubricity--Evaluation of lubricity was performed using a pin-on-disk tester. The test was carried out on an aluminum test piece (6 μm) whose surface was anodized with a thickness of 40 μm.
A disk (counterpart) having a diameter of 0 mm and a thickness of 6 mm, Rmax = 25 microns) was rotated at 1000 rpm, and pins of various compositions according to the present invention were pressed against the surface with a load of 1 kg to measure. The results were evaluated as excellent when the friction coefficient was 0.1 or less, good when the friction coefficient was 0.1 or more and less than 0.25, and slightly poor when the friction coefficient was 0.25 or more.

Wear rate of counterpart material-In the above-mentioned pin-on-disk test, the weight of the counterpart material was measured after 50 hours, and when the wear weight was less than 3 mg, it was excellent.
The case of less than 5 was judged as good, and the case of 5 mg or more was judged as slightly bad.

Injection moldability-Injection moldability is 2 mm in cross section.
An injection mold having a scroll-shaped cavity having a size of 2 mm and a total length of 600 mm is prepared, and 6 to 8 parts by weight of a fluorocarbon polymer having a mold temperature of 200 ° C. and a barrel temperature of 29 is added thereto. 0-340 ° C, nozzle temperature 370 ° C, injection pressure of the molten resin of the present invention is 80 MPa.
And the length of the molded product was measured and judged. That is, when the flow length of the resin was 550 mm or more and 600 mm or less, it was determined to be excellent. When the flow length was 500 mm or more and less than 550 mm, it was determined to be good.

Overall Evaluation-The results of the above four items were judged as a whole.

When PAI is used as the main component of the chip seal material, MoS ₂ is a main lubricant, and the presence of MoS ₂ is large in the lubricating action under dry conditions. However, under high temperature, oxidation with oxygen in the air is promoted, and 2Mo
The reaction of S ₂ + 3O ₂ ⇒2MoO ₃ + 2S ₂ (gas) proceeds. As a result, the generated sulfur is oxidized to SOx
(Gas), and MoO ₃ has a reduced bonding force with the binder and is easily peeled. Even if MoO ₃ remains in the tip seal, MoO ₃ has a low lubricating property, so that the lubrication function of the tip seal is reduced as a whole. Therefore, as described above, the PAI as the main component is set to 40 parts by weight (constant), Sb ₂ O ₃ and C are fixed, and Mo is set.
Changing the ratio of S _2, then MoS ₂ and the C constant Sb ₂
The examination was performed by changing the ratio of O ₃ . As a result, MoS ₂
However, up to 6 parts by weight, lubricity and abrasion resistance are improved, but thereafter slightly lowered. Therefore, 6 parts by weight of MoS ₂ is preferred. In addition, the anti-oxidation effect of MoS ₂ by Sb ₂ O ₃ is as follows.
Is improved with increasing Sb ₂ O _3, the ratio of Sb ₂ O ₃ as compared to the MoS ₂ is too large, lubricity and abrasion resistance is found to decrease. It is considered that the reason is that the amount of PAI as a main component resin (aggregate resin) is relatively short. Therefore, the appropriate ratio of MoS ₂ / Sb ₂ O ₃ was 1.2 to 2.0, and 1.5 was found to be the optimum value.

Next, the optimum amount of C was examined. Other factors were fixed and only C was varied in the range of 0.6 to 1.0 parts by weight. As a result, it was found that C was good in the range of 0.7 to 0.9 part by weight, and 0.8 part by weight was the optimum value.

Finally, PAI, MOS ₂ , S
The values of b ₂ O ₃ and C were set to the above-mentioned optimum values (constant), and the ratio of PTFE as an organic solid lubricant was examined by adding every 0.5 in the range of 6 to 8 parts by weight. As a result, it was found that all of the heat resistance, lubricity and wear resistance were affected by the proportion of PTFE, and it was revealed that the lower the proportion of PTFE, the better the heat resistance. However, the lubricity has a peak at around 7 parts by weight of PTFE, and the abrasion resistance also has a peak at around 7 parts by weight. Overall, the blending of PTFE is 6.5 to 7.5. The parts by weight range proved to be appropriate. From the above examination results, it was clarified that the composition of the chip sealing material was good in the proportions shown in Tables 1 and 2, and particularly the composition ratio in Table 2 was more excellent.

[0034]

[Table 1]

[0035]

[Table 2]

Next, the relationship between the heating temperature (predetermined temperature × 20 hours) and the hardness of the tip sealing material (thickness: 3 mm) having the optimum composition shown in Table 2 was examined. We decided to judge. That is, the hardness of the molded chip seal material was measured by a Vickers hardness tester using a sample in which the heating temperature was changed every 50 ° C. between 200 and 440 ° C. The results are as shown in FIG. 2 (A), and the figure also shows the result (B) of the tip seal of the conventional combination. The hardness of the tip seal of the present invention is equal to or slightly lower than that of the conventional product at a heating temperature of 150 to 200 ° C., but rapidly rises with an increase of the heating temperature and reaches 350 ° C., and Hv = 60 at 200 ° C. It becomes twice as hard.
And it softens a little at 400 degreeC, and it becomes Hv = 50. The fact that the peak of the hardness at about 350 ° C. is very suitable as a tip seal material used in a large, high-speed, high-performance oil-free scroll compressor. On the other hand, the hardness of the conventional product only decreases after 200 ° C., and the usefulness of the tip seal of the present invention is apparent.

[0037]

[Table 3]

Next, with respect to the chip seal material according to the present invention and the conventional chip seal material shown in Table 3, the examination results of heating temperature and wear resistance will be described.

The evaluation of wear resistance was performed using an Amsula tester. In the test, two ring-shaped samples each having a diameter of 40 mm and a length of 10 mm were pressed at a pressure of 10 kgf, and a relative slip of 1 at 190 rpm.
The sliding was performed by generating 0%. For one of the samples, a hard aluminum material subjected to alumite treatment was used as a mating material.

The relationship between the heat treatment temperature of the sample of the chip sealing material of the present invention and the time until the start of the generation of abrasion powder was determined by an Amsula test. The longer the time until the generation of wear powder, the better the wear resistance. FIG. 3A shows the result. The result of the chip seal of the conventional composition shown for comparison is also shown as (B) in the same figure. As is clear from FIG. 3, at a temperature of 205 ° C. or lower, the conventional chip sealing material had better results. However, on the high temperature side from this temperature, the chip seal material according to the present invention shows good wear resistance, and when heat treated at 300 ° C., the time to start generating wear powder is about the same as that of the conventional chip seal material. 1
80 times. Also, in contrast to the conventional chip sealing material in which the time until the generation of wear powder decreases when the temperature rises, the chip sealing material according to the present invention increases the time until the generation of wear powder as the heating temperature increases, and as described above. When evaluated together with the results of the lubrication performance test, the high-temperature characteristics were significantly improved as compared with the conventional PTFE-PI-based chip seal material.

Next, with respect to the tip seal of the present invention and the conventional tip seal, the results of the examination of the heating temperature and the long-term lubricity will be described. Evaluation of long-term lubricity was also performed using the above Amsula tester. The test was carried out by pressing two ring-shaped samples each having a diameter of 40 mm and a length of 10 mm at a pressure of 10 kgf, and sliding at 190 rpm with a relative slip of 10%.
The mating material of the evaluation test piece is a hard aluminum material subjected to alumite treatment. The long-term lubricity of the tip sealing material of the present invention is
At each heating temperature, the friction distance was determined until the frictional transfer became 0.3.

FIG. 4A shows the experimental results of the tip seal of the present invention, and FIG. 4B shows the results of the conventional product. Although the wear resistance of the conventional product deteriorates with an increase in the heating temperature, the wear resistance of the tip seal of the present invention is improved and peaks at about 400 ° C., and then slightly decreases. As the heating temperature increases, long-term lubricity improves. Particularly at about 320 ° C., the long-term lubricity is greatly improved, but at about 400 ° C. or more, R slightly decreases. Therefore, it is clear from these results that the present invention is excellent as a composition of a tip seal used in a large-sized, high-speed oil-free scroll compressor in which the temperature in the compression chamber is about 230 to 260 ° C. or more. .

Furthermore, since the function as a tip seal improves as the heating temperature, in other words, the ambient temperature inside the scroll increases, it has a unique function that cannot be considered as an extension of the conventional technology. An ultra-high-speed oil-free scroll compressor has also been realized.
Hereinafter, based on the above-mentioned examination results, the effect was confirmed by applying the tip sealing material according to the present invention having the best characteristics to an actual oil-free compressor.

(Embodiment 2) The basic structure of a compressor according to an embodiment of the present invention will be described with reference to FIGS. FIG. 5 is a longitudinal sectional view showing the overall structure of a scroll type compressor of a type in which a plurality of crankshafts are arranged on the outer peripheral portion of the end plate of the orbiting scroll to cause the orbiting scroll to orbit. FIG. 6 is a cross-sectional view showing the meshing state of the wraps in the cross-sectional view taken along the line AA of FIG. 5 and shows a state where a compression working chamber is formed by the wraps of the orbiting scroll and the fixed scroll. For convenience of explanation, the crankshafts 4 and 5 and the balance weights 17 and 18 and the bearing 11 disposed on the orbiting scroll 3 shown in FIG.

In FIG. 5, the scroll compressor comprises a fixed scroll 1 having a scroll wrap 1b formed in a spiral shape and a scroll wrap 2b formed in the same manner.
The orbiting scroll 3 having the scroll wraps 3b and 3c which are also formed in a spiral shape on both sides of the end plate 3a is engaged with each fixed scroll. The wraps 3b and 3c of the orbiting scroll 3 have a predetermined thickness, and an envelope formed when the orbiting scroll orbits with a constant radius forms a basic line of the fixed scroll wrap. Practically, the orbiting and fixed wraps are configured to engage with each other while maintaining a non-contact state, and form compression working chambers 14 and 15 on both sides of the end plate 3a of the orbiting scroll 3. These compression working chambers 14 and 15 are formed in a crescent shape by both scroll wraps as shown in FIG. In the scroll compressor, such a crescent-shaped compression working chamber 14 has a pair of chambers (compression working chambers 14 ') symmetrically with respect to the central axis, and has approximately the same volume. The compression working chamber 14 is configured to continuously move to the center in accordance with the orbital movement of the orbiting scroll 3. The volume of the compression working chamber 14 is gradually reduced from the outer periphery toward the center.

Further, as shown in FIG.
The tip seals 1c, 1c of the fixed scroll 2 and the orbiting scroll 3 are formed of a composite resin material containing the PAI resin according to the present invention as a main component and other organic components and inorganic components as subcomponents. 2c,
3d and 3e are respectively provided along the spiral,
When shown in a plan view as shown in FIG. 6, the tip seal 1c is disposed on the tip end surface of the wrap, and is divided into a plurality of pieces in the length direction along the spiral. This chip seal does not need to be divided if there is no particular problem in function and performance, but by dividing it, the escape of the amount of thermal expansion during compressor operation can be set appropriately, so that the sealing performance and reliability can be improved. Performance can be improved.

The fixed scrolls 1 and 2 and the orbiting scroll 3 are each made of a light material having good heat conductivity as represented by an aluminum alloy or the like. However, since aluminum alloys have lower strength than iron-based ones, it is desirable to apply high-strength high-Si aluminum alloys for oil-free compressors. Furthermore, in order to improve the lubricity at the time of wrap contact or to provide a reliable oil-free compressor against seizure at the time of contact, high Si aluminum A surface treatment such as an anodic oxide film treatment for an alloy is performed.

In the case of the oil-free scroll compressor to which the present invention is applied, the fixed scroll side is suitably cooled by the fins provided on the outer surface, so that the temperature of the sliding surface is controlled by design. can do. However, as for the orbiting scroll, since it is arranged in a sandwich shape on the fixed scroll and is orbiting, it is difficult for cooling air to flow in simply by providing a small through hole in the end plate, so that means such as fan cooling is used. However, the cooling effect is small and the temperature of the parts does not decrease so much. For this reason, the tip seal provided at the tip of the fixed scroll slides on the surface of the orbiting scroll wrap end plate that has become hot. Therefore, there is a problem that the wear amount of the tip seal provided on the fixed scroll is larger than that of the tip seal provided on the orbiting scroll.

However, as a result of applying the tip seal according to the present invention, during operation of the compressor, both scroll wraps are in non-contact and the gap can be kept small, so that both scroll members are kept at an appropriate temperature. It is. Therefore, the amount of thermal expansion can be kept very small, so that a high-performance compressor can be provided. Further, even if the scroll member is made of an aluminum alloy, it can be maintained at an appropriate temperature, so that the fatigue strength can be set in a high state, and a highly reliable compressor can be provided. Furthermore, the amount of wear of the seal member applied to the tip of the scroll wrap, that is, the amount of wear of the tip seal is also affected by the temperature of the sliding surface. Generally, the higher the temperature, the greater the amount of wear. However, as described above, and as apparent from FIGS. 2 to 4, the tip seal of the present invention improves wear resistance up to about 350 ° C. as the ambient temperature increases, contrary to general wisdom. Noticeable features are seen.

Therefore, according to the present embodiment, the orbiting scroll 3
And the amount of wear of the tip seals provided at the tips of the wraps of the fixed scrolls 1 and 2 can be kept very small, so that the compressor can maintain high performance over a long period of time, and the tip seal replacement time can be extended. Since it can be set, the operation cost for tip seal replacement can be reduced. By the implementation of the present invention, the replacement period of the tip seal is extended to about three times that of the conventional one, and the maintenance period of the initial performance is similarly extended.

[0051]

According to the present invention, since the wear rate of the tip seal can be kept low, long-term reliability against the wear of the tip seal can be obtained, and stable compressor performance can be obtained over a long period of time. A high-speed, high-performance large oil-free scroll compressor can be provided, and the wear speed of the tip seal can be delayed, so that the time for replacing the tip seal can be set longer. Further, since the lap gap between the orbiting and fixed scrolls can be kept in a minute state for a long time, an oil-free scroll compressor with high performance and high reliability can be provided.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view of a tip sealing material according to an embodiment of the present invention.

FIG. 2 is a characteristic diagram showing the relationship between the heating temperature and the hardness of the tip sealing material according to one embodiment of the present invention.

FIG. 3 is a characteristic diagram showing a relationship between a heating temperature of a chip sealing material and a friction time until generation of abrasion powder according to one embodiment of the present invention.

FIG. 4 is a characteristic diagram showing a relationship between a heating temperature of a tip sealing material and an Amsla wear test according to one embodiment of the present invention.

FIG. 5 is an overall sectional view of an oil-free scroll compressor showing one embodiment of the present invention.

FIG. 6 is a plan view showing a state where a wrap portion of a fixed scroll is meshed with the orbiting scroll in one embodiment of the present invention.

[Explanation of symbols]

A: Experimental results using molded articles of the present invention, B: Experimental results using molded articles of the conventional composition, 1 ... fixed scroll, 2 ... fixed scroll, 3 ... orbiting scroll, 4 ... main crankshaft, 5 ... auxiliary crankshaft, 6 pulley, 7 timing belt, 8 communication hole, 9 discharge port, 10, 11, 1
2 ... bearing, 13 ... elastic support member, 14, 15 ... compression working chamber, 17, 18 ... balance weight, 20 ... toothed pulley, 22, 23 ... suction hole.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Shigeru Machida 502 Kandate-cho, Tsuchiura-shi, Ibaraki Pref. Machinery Research Laboratory, Ltd. Inside the Machinery Research Laboratory (72) Inventor ▲ Yoshi ▼ Yuji Tomi 502, Kandachi-cho, Tsuchiura-shi, Ibaraki F-term in the Machinery Research Laboratory, Hitachi Ltd.

Claims (1)

[Claims] An orbiting scroll having spiral scroll wraps on both sides of a head plate is arranged between said fixed scrolls, and spiral wrap surfaces of a pair of fixed scrolls are arranged in parallel with each other. A plurality of compression working chambers are formed by engaging a spiral wrap with the orbiting scroll and the fixed scroll on both sides of the end plate, and the orbiting scroll is orbited by a plurality of crankshafts arranged on the outer peripheral portion of the orbiting scroll. In a scroll fluid machine in which a scroll fluid machine having a structure for compressing gas in compression operation chambers on both sides of an orbiting scroll head plate is housed in a unit, and a unit device thereof, a groove is formed at a tip portion of each of the scroll wraps. A chip comprising a thermosetting resin having an imide group and a solid lubricant. Unit device scroll fluid machine, characterized by being configured by disposing a seal.