JP2005061351A - Fluid machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a high-precision slide member such as a movable scroll with high abrasion resistance and low sliding loss at a favorable yield, and a fluid machine such as a compressor and a pump of high reliability and high efficiency. <P>SOLUTION: On the surface of a slide part of the movable scroll 3, an anodized layer 36 is formed, and prescribed thickness is eliminated from the surface of the anodized surface 36. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a fluid machine that conveys fluid, and particularly relates to a compressor that is used in a refrigeration apparatus, an air conditioner, and the like, and relates to a compressor that compresses carbon dioxide gas, which is a high-pressure refrigerant gas, to a high pressure. is there.

  As the compressors for refrigerating and air-conditioning, there are reciprocating, rolling piston, and scroll types of compression mechanisms, and any of these methods is used in the field of refrigerating and air-conditioning for home use and business use. Both types of compressors are configured by accommodating a compression mechanism, a driving shaft, an electric motor, and the like in an airtight container (see, for example, Patent Document 1).

  Here, a conventional technique will be described by taking a scroll compressor as an example when the HCFC refrigerant R22 is used as a working gas.

  FIG. 5 shows a longitudinal sectional view of a conventional scroll compressor.

  Inside the hermetic container 1 are a compression mechanism portion 2 composed of a fixed scroll 2a and a movable scroll 3, a shaft 5 for rotating the movable scroll 3 with respect to the fixed scroll 2a via an Oldham coupling 4, and a fixed scroll. A bearing member 6 is provided that fixes the shaft 2a and rotatably supports the shaft 5.

  A rotor 7 a of an electric motor 7 is attached to the shaft 5, and is disposed below the bearing member 6 together with a stator 7 b that is shrink-fitted and fixed to the body shell 20.

  An oil sump 10 for storing the lubricating oil 9 is provided at the lower bottom of the sealed container 1, and the oil 9 in the oil sump 10 is removed from the lower end of the through hole 13 of the shaft 5 by the oil pump 17 as the shaft 5 rotates. Suction, journal bearing 6a, eccentric bearing 3a, and supply to each sliding surface such as fixed scroll 2a and movable scroll 3.

  Next, the refrigerant gas compression cycle in the conventional scroll compressor having the above-described configuration will be described. The low-pressure refrigerant gas that has circulated through the heat exchanger (not shown) of the air conditioner is sucked into the compression mechanism 2 through the suction pipe 11.

  The sucked refrigerant gas enters a crescent-shaped compression space (not shown) formed between the fixed scroll 2 a and the movable scroll 3, and the crescent-shaped compression space is centered from the outside by the turning motion of the movable scroll 3. The refrigerant gas is compressed to become a high-pressure gas and is discharged from the discharge hole 12 by being gradually reduced toward.

  The high-pressure gas discharged from the discharge hole 12 is once discharged into the discharge space 1a above the fixed scroll 2a in the hermetic container 1, flows through the gas passage 14 to the lower space 1b in which the electric motor 7 is accommodated, and the rotor 7a. From the gas passage 18a provided in the inside to the bottom space 1c of the hermetic container 1 further flows upward through the passage 18b provided on the outer periphery of the stator 7b, and through the gas passage 15 provided separately from the passage 14, the fixed scroll It flows into the space 1e above 2a and is discharged from the discharge pipe 16 to an external air conditioning system such as a heat exchanger (not shown). The high-pressure gas circulates in a heat exchanger or the like of the air conditioner in the air-conditioning system to become a low-pressure gas and constitutes a known compression cycle that returns to the compressor from the suction pipe 11 again.

  Next, the lubricating oil circulation cycle for supplying the lubricating oil 9 to each sliding portion in the conventional scroll compressor will be described. The lubricating oil 9 sucked up by the oil pump 17 from the oil sump 10 rises in the through hole 13 of the shaft 5, lubricates and cools the eccentric bearing 3a, the journal bearing 6a, and the sliding portions, and the journal bearing 6a. The oil is discharged from the lower oil discharge port to the upper portion of the rotor 7a and forms a lubricating oil circulation cycle that returns to the bottom oil sump 10 through the passage 18a in the rotor 7a.

  Further, part of the lubricating oil 9 that has passed through the eccentric bearing 3 a also adjusts the pressure in the back pressure space 22 in which the Oldham coupling 4 is installed and the pressure in the back pressure space 22 from the boss space 21 below the movable scroll 3. The refrigerant is led to the suction side compression chamber 24 through the suction back pressure adjusting valve 23 and is returned to the oil sump 10 at the bottom through the gas passages 14 and 18a from the discharge hole 12 together with the refrigerant gas compressed by the turning motion of the movable scroll 3. A lubricating oil circulation cycle is formed. In the course of this circulation cycle, the Oldham coupling 4, the movable scroll 3, the fixed scroll 2a and other sliding parts are lubricated and cooled.

  However, in order to cope with global environmental problems, HFC refrigerants that are more efficient and have a lower global warming potential than conventional CFCs such as R12 and HCFC refrigerants such as R22, which are more suitable for suppressing global warming ( For example, use of a device that uses, as a refrigerant, a natural refrigerant (eg, carbon dioxide (hereinafter referred to as CO2)) having a smaller global warming potential, such as an HFC refrigerant having R410A or R32 as a main component. Is underway.

  Many of these refrigerants require a higher operating pressure than the conventional refrigerant R22 or the like in order to increase the system efficiency of the equipment due to the characteristics of the refrigerant, and the sliding portion is slid while receiving a large force according to the pressure. Move.

  For example, in the case of the configuration of the compressor shown in FIG. 5, the movable scroll 3 is swung while being pressed against the fixed scroll 2a by the pressures of the boss space 21 and the back pressure space 22. As shown, the compression chamber thrust surface 32b of the fixed scroll 2a and the wrap end surface 33a (upper surface side in the drawing) of the movable scroll 3, as well as the wrap end surface 32a (lower surface side in the drawing) of the fixed scroll 2a and the movable scroll 3 The compression chamber thrust surfaces 33b slide on each other while receiving the load.

  Further, the key portion 4a of the Oldham joint 4 and the key groove portion 3b of the movable scroll 3 are also slid against each other under the load as described above.

  In these sliding parts, under severe operating conditions and operating conditions of high differential pressure in refrigerant gas for replacement of conventional Freon HCFC (such as HFC refrigerant R410A without natural chlorine and natural refrigerant CO2 which has a lubricating action) During operation, an excessive load is generated, the lubricating oil film of the sliding portion becomes very thin, and a mixed lubrication state is brought into partial contact (close to boundary lubrication). When this mixed lubrication state (similar to boundary lubrication) continues, wear occurs on the surface of the sliding portion, causing a problem of impairing reliability.

  In order to cope with this problem, for example, when a material mainly composed of aluminum is used as the base material of the movable scroll 3, a method of forming an anodized layer on the surface of aluminum has been proposed (for example, Patent Documents). 2, see Patent Document 3).

  A method using sulfuric acid or oxalic acid is generally used to form the anodized layer. An anodized layer formed on a material mainly composed of aluminum is usually called anodized.

FIG. 7 shows an outline of the manufacturing process of the movable scroll 3 in the case of forming a conventional anodic oxide film. First, a pre-finishing process that leaves a machining allowance (for example, about 20 μm) from the movable scroll material to a substantially finished shape, and then a finishing process that finishes to a predetermined accuracy. In the anodizing process, a predetermined anodized film is formed on the surface. Further, there may be a masking step of covering a portion where the anodic oxidation layer is not formed or a portion where the treatment liquid or the like in the anodic oxidation step is not mixed with a resin before the anodizing step.
JP 2002-161856 A JP-A-6-167243 Japanese Patent Application Laid-Open No. 7-126871

  However, although the wear resistance is improved in the conventional configuration, the surface roughness is increased when the anodized layer is formed thick. FIG. 8 is a cross-sectional view of the vicinity of the surface of the movable scroll 3 on which an anodized film is formed. An anodized layer 26 having a thickness δ0 is formed from the surface. Since the surface roughness is usually rougher than the surface roughness after the finishing step, it was difficult to obtain the desired surface roughness.

  For example, when the anodic oxide layer 26 having a thickness of about 20 μm is formed, the surface roughness Rmax is as large as about 10 μm, which causes problems such as a large friction coefficient of the sliding portion and poor conformability.

  In order to solve this, a method has been proposed in which the surface roughness is reduced by using a rectified direct current as the applied current when forming the anodic oxide film, but this method requires modification and introduction of processing equipment. Could not be implemented easily. In addition, the surface roughness and film thickness accuracy due to the effect are also inadequate for application to the movable scroll of the above embodiment, and as it is, the productivity is low due to the manufacturing yield, and the surface is familiar. Therefore, there is a problem that sliding efficiency is large and sufficient efficiency cannot be secured.

  The present invention solves the conventional problems as described above, and realizes a high-precision sliding member such as a movable scroll with high wear resistance and low sliding loss with a high yield, and uses it. An object is to provide a fluid machine such as a compressor or a pump having high reliability and efficiency.

  In order to achieve the above object, the fluid machine of the present invention has a sliding member obtained by forming an anodized layer on a sliding surface and then removing the anodized layer from the surface to a predetermined thickness.

  According to the present invention, when a refrigerant having a high operating pressure such as CO2 is used, an anodized layer having a low surface roughness can be formed on the sliding surface of the sliding member, and the sliding has a high wear resistance and a low sliding loss. Since the members can be made with high productivity, a highly reliable fluid machine can be realized at low cost.

  Embodiments of the present invention will be described below with reference to the drawings. In the configuration of the scroll compressor used in the embodiment of the present invention, the same reference numerals are used for the same functional parts as those of the prior art example described with reference to FIG. 5, and the description of the same configuration and operation is omitted. .

  Further, the scroll compressor according to the embodiment of the present invention will be described by taking an example in which carbon dioxide is used as a refrigerant (hereinafter referred to as CO2). It is also applicable to the case where the pressure exceeds 5 MPa, the case where HFC refrigerant R410A, R32, or hydrocarbon (HC)) or the like, or a lower refrigerant such as conventional HCFC22 is used, Similar effects can be obtained.

(Embodiment 1)
Embodiment 1 of the present invention will be described with reference to FIGS.

  FIG. 1 is a cross-sectional view showing the vicinity of an anodized layer formed on a movable scroll according to an embodiment of the present invention. FIG. 2 is a manufacturing process diagram of the movable scroll according to the embodiment of the present invention, and FIG. 3 is a longitudinal sectional view of the movable scroll.

  The difference between the configuration of FIG. 1 which is the first embodiment and the conventional configuration is that after the anodizing step, a finishing step is provided in which the surface is removed from the surface of the anodized layer to a predetermined thickness and finished. The manufacturing process will be described with reference to FIG.

  First, the outline of the manufacturing process of the movable scroll 3 of FIG. 2 (see FIGS. 3 and 5) will be described. First, the movable scroll material is processed to a substantially finished shape in the pre-finishing process in consideration of a machining allowance (for example, about 20 μm is required from the finishing accuracy). Next, in an anodizing process, an anodized layer is formed on the surface to a predetermined thickness (here, about 40 μm to 50 μm). After the formation of the anodized layer 26, finishing is performed with a predetermined size and accuracy (the machining allowance is almost thick and the surface is finished to the desired roughness) in the finishing process, and the movable scroll 3 is completed.

  FIG. 1 is a cross-sectional view of the vicinity of the anodized layer 36 after the anodizing process. The processed surface after the pre-finishing process is the AA line in the figure. With the formation of the anodic oxide layer 36, an initial anodic oxide layer having a thickness δ1 is formed which is thicker on the surface side (upward in the figure) than the line AA. For example, when the thickness is about ½ of the initial anodized layer thickness δ1 depending on the processing conditions, the initial anodized layer thickness δ1 is about 40 μm, and the thickness is about 20 μm (from the line AA in FIG. To the surface). Further, the roughness of the surface becomes rougher than the surface roughness before the treatment, for example, Ra is about 5 μm (changes from Ra before the treatment), but the anodized layer is removed in the finishing step after the anodizing treatment step. By removing only, the target surface roughness (for example, Ra 0.2 μm or less) can be obtained. Before the anodizing treatment step, a masking step for covering a portion where the anodized layer is not formed or a portion where the treatment liquid or the like in the anodizing step is not mixed with a chemical resistant resin can be provided as necessary. .

  FIG. 3 is a cross-sectional view of the movable scroll 3. Here, a masking jig 37a is mounted so that an anodized layer is not formed on the eccentric bearing portion 3a. The anodized layer 36 is formed on the surface of the broken line in the figure (wrap end surface 33a, wrap side surface 33c, thrust surface 33b, end plate surface 33d, key groove portion 33e). After the anodic oxide layer 36 is formed, the end plate thickness t1, the wrap height t2, and the wrap thickness t3 are finished to a predetermined accuracy.

For example, the case of finishing the end plate thickness will be described. In order to make the thrust surface 33b to be the sliding surface into the anodized layer 36 having a predetermined surface roughness (for example, about 0.2 μm in Ra), the surface roughness (for example, about Ra in the surface of the anodized layer 36 before finishing). By removing the above from the surface (removed thickness δ3) and finishing, the previous surface roughness can be obtained. Prior to finishing on the thrust surface 33b side, a predetermined machining allowance (= end plate thickness before finishing−end plate thickness t1−removed thickness δ3 from the thrust surface 33b side) is removed from the end plate surface 33d side, and then the thrust surface 33b. The removal thickness δ3 is removed from the side. The procedure is not limited to this, and on the contrary, the thrust surface side may be finished first. The wrap height and wrap thickness are finished in the same manner.

  In addition, by installing the mask jig 37b as shown in FIG. 4, it is possible to form only the wrap end surface 33a, the wrap side surface 33c, and the thrust surface 33b without forming the anodized layer 36 on the end plate surface 33d and the key groove portion 33e. .

  Further, when the movable scroll 3 is made of a material mainly composed of aluminum and containing, for example, about 10% to 30% of silicon particles having an average particle diameter of 3 to 5 μm, the silicon particles are difficult to conduct electricity. The layer is also harder to form than with a single aluminum. Due to the distribution of silicon particles, non-uniformity of the anodized layer is likely to occur, and the surface roughness tends to be rough. Especially in such a case, it is effective in improving the surface roughness. In other words, by applying the method of the above embodiment, the surface is finished after the anodic oxidation step, thereby eliminating the influence and obtaining an anodic oxide layer having good surface roughness. Of course, the present invention can be applied even when the silicon content is 10% or less. Alternatively, it may be applicable in the case of 30% or more, but the production cost of the material is high, the formation rate of the anodized layer is low, and the productivity is low.

  It should be noted that the silicon average particle diameter is not limited to 3 to 5 μm, and it goes without saying that the present invention can be applied even when the particle diameter is larger or smaller.

  In the above embodiment, the case where the scroll type compression mechanism is provided has been described as an example. However, the present invention can be applied to other rotary type and reciprocating type compressors and pumps. It goes without saying that the effects of can be realized. In particular, when a reduction in size and weight is required, the mechanism part is often made of an aluminum alloy. In such a case, the present invention can exhibit more effects. That is, by applying the present invention, the surface roughness can be improved, and a fluid machine with high reliability and productivity can be realized.

  As described above, according to the configuration of the above embodiment, it is possible to significantly improve the surface roughness of the anodized layer as compared with the prior art, and to improve the reliability of a hermetic compressor such as a scroll at a low cost. Can do.

  In the above-described embodiment, the case where the CO2 refrigerant is used has been described as an example. However, the present invention is not limited to the CO2 refrigerant, and even when a refrigerant whose operating pressure is equal to or lower than the CO2 refrigerant is used. It goes without saying that the same effect can be obtained.

  As described above, the present invention can provide a fluid machine having a sliding member that is lightweight, excellent in wear resistance, and having low frictional resistance. It can also be applied to applications such as equipment and refrigeration equipment, as well as hot water supply equipment equipped with a heat pump system using CO2 refrigerant.

Sectional drawing of the sliding surface layer part by embodiment of this invention Manufacturing process diagram of movable scroll according to the embodiment of the present invention Sectional drawing of the movable scroll by embodiment of this invention Sectional drawing of the movable scroll by embodiment of this invention Longitudinal sectional view of a conventional scroll compressor Cross-sectional view of conventional main part Production process diagram of conventional movable scroll Sectional view of the surface layer of a conventional movable scroll sliding surface

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Airtight container 1a Discharge space 1b Lower space 1c Bottom space 2 Compression mechanism 2a Fixed scroll 3 Movable scroll 3a Eccentric bearing 4 Oldham joint 5 Shaft 6 Bearing member 6a Journal bearing 7 Electric motor 7a Rotor 7b Stator 9 Lubricant 10 Oil sump DESCRIPTION OF SYMBOLS 11 Intake pipe 13 Through-hole 14 Passage 15 Passage 16 Discharge pipe 17 Oil pump 18a Passage 18b Passage 20 Body shell 21 Boss part space 26 Anodized layer 36 Anodized layer 37 Mask jig

Claims (5)

A fluid machine comprising: a sliding member having an anodized layer formed on a sliding surface, wherein the anodized layer is removed from the surface to a predetermined thickness after the anodizing treatment step. The fluid machine according to claim 1, wherein the removal thickness of the anodized layer is equal to or greater than the roughness (Ra) of the surface of the anodized layer before removal. The fluid machine according to claim 1 or 2, wherein the sliding member is mainly composed of aluminum and contains silicon in an amount of about 10% to 30%. The fluid machine according to any one of claims 1 to 3, wherein the fluid machine has a scroll-type compression mechanism, and the sliding member is the movable scroll or the fixed scroll. The fluid machine according to any one of claims 1 to 4, wherein the working gas is mainly composed of HFC refrigerant or carbon dioxide.

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