JP2005147137A - Slide part and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a small size and inexpensive slide part for a compressor and its manufacturing method by increasing hardness and imparting sufficient abrasion-resistance. <P>SOLUTION: A material is manufactured by metal injection molding using an alloy powder having a particle diameter less than 30 micrometer or the material is manufactured by green compact sinter molding using an alloy powder having a particle diameter of 40 micrometer or more. Nitriding treatment is carried out. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a sliding component that is used with increased hardness by heat treatment and a method for manufacturing the same, and more particularly to a sliding component for a compressor.

  In the case of a compressor used in an air conditioner or the like, surface treatment is performed on sliding parts and sliding parts to improve wear resistance and to extend the life or reliability. For example, sliding parts for compressors with increased hardness are used after roughing nitrided steel such as SACM645, then nitriding and finishing to harden the surface to about Hv900 doing.

  In this case, the material forming of the nitrided steel is performed by cutting out from the steel material of the molten material, or forming the molten material by hot forging with an accuracy of about 1 millimeter on one side of the rough machining, and then cutting out the material. However, it is difficult to manufacture parts. However, in such a process, there is a problem that it is not easy to manufacture parts and manufacturing costs are high.

  Further, as shown in FIG. 5, the finishing region 14 is removed by finishing after nitriding, and the exposed surface 15 becomes the use surface, but the hardness of the use surface 15 is only about Hv950.

  Therefore, after grinding to remove the surface of the wear parts for the compressor, nitriding to harden the surface is performed, and further, grinding is performed to remove the surface within a range of 0.25 mm or less in diameter, and sliding The thing which makes the surface hardness Hv1000 or more is also proposed (for example, refer patent document 1).

JP 2002-98052 A

  Recently, there is a demand for downsizing of parts, so that the force applied to the sliding parts for the compressor tends to increase. Even if the method described in Patent Document 1 is used, the compressor has sufficient wear resistance. It was difficult to reduce the size of sliding parts for use, and it was necessary to further improve wear resistance.

  The present invention has been made in view of such problems of the prior art, and provides a small and inexpensive sliding component by increasing hardness and imparting sufficient wear resistance, and a method for manufacturing the same. The purpose is to do.

  In order to achieve the above object, the invention according to claim 1 of the present invention is to manufacture a material by metal injection molding using an alloy powder having a particle size of less than 30 micrometers and perform nitriding treatment. The manufacturing method of the sliding component characterized by this.

  According to a second aspect of the present invention, there is provided a sliding part characterized in that an alloy powder having a particle size of 40 micrometers or more is used to produce a raw material by compacting and forming a nitriding treatment. It is a manufacturing method.

  Furthermore, the invention described in claim 3 is a sliding component manufactured by the manufacturing method described in claim 1 or 2.

  The invention according to claim 4 is characterized in that, in the scroll compressor, the sliding component is a compressor bush that is rotatably supported by a bush fixed to the movable scroll.

  According to the present invention, a raw material is manufactured by metal injection molding using an alloy powder having a particle size of less than 30 micrometers, or a green compact is sintered using an alloy powder having a particle diameter of 40 micrometers or more. Since the material is manufactured by sinter molding and nitriding is performed, the surface hardness can be improved and sufficient wear resistance can be given compared to the melted material, and a small sliding part can be provided. Can do. Further, since the machining allowance for roughing is less than that for manufacturing from the melted material, the manufacturing cost is reduced, and an inexpensive sliding part can be provided.

  Further, since the surface hardness is improved as compared with the conventional case, it is possible to further reduce the thickness of the parts constituting the sliding portion in the compressor or the like of the air conditioner, and to reduce the size of the compressor. At the same time, reliability can be improved.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
(Embodiment 1)
FIG. 1 shows parts used in a scroll compressor called a complas bush, and is an example of a compressor part according to the first embodiment of the present invention.

  This compressor part 1 is manufactured by metal injection molding of stainless steel powder particles equivalent to SUS420J2, and after the inner and outer parts are roughly machined to about 0.05 to 0.2 mm, the temperature is about 590 ° C. Is subjected to nitriding treatment for about 9 hours, and then the inside and outside are finished to 20 to 100 micrometers. Note that the dense and adhesive strong oxide film on the surface of chromium-containing stainless steel or heat-resistant steel is removed using, for example, organic chloride, hydrogen fluoride, hydrogen sulfide, or the like.

  FIG. 2 is a hardness distribution curve of a compressor part shown in FIG. 1 and a part obtained by performing nitriding treatment on a melted material of the same material under the same conditions. The vertical axis represents the micro Vickers hardness, and the horizontal axis represents the distance from the surface.

  As can be seen from FIG. 2, the hardness 2 after nitriding of the part manufactured by metal injection molding is increased by nearly 150 points compared to the hardness 3 of the part manufactured from the molten material of the same component. It can be seen that the depth of is shallower. This is because so-called decarburization in which carbon escapes from the chromium carbide occurs because the metal injection-molded product is fired under conditions where air of about 2 bar is present. This decarburization occurs while the metal injection-molded product is dewaxed and sintered to a density of 98% or more from a state where the density is about 50%, and thus decarburization has occurred to the inside. After firing, when roughing is performed and further nitriding is performed, chromium effective for hardening by nitriding remains more than the smelted material due to decarburization, so there is more chromium nitride than the nitriding product of the smelted material. It is thought that the hardness becomes stiff.

  In addition, the metal injection molded product has a lower hardness than the melted material. If the nitriding treatment is the same, the metal injection molded product has a large amount of chromium, so that nitrogen forming chromium nitride is formed on the surface side. It is thought that it is consumed. In addition, it is easy to obtain the same depth of hardness as that of the molten metal by extending the time, adjusting the ammonia gas concentration, etc., so it is easier to achieve a hard surface. can do.

  Furthermore, if the main purpose is to obtain a hard surface, the treatment can be carried out under the same nitriding conditions as the melted material, which is economical and can obtain a higher hardness by nitriding than the melted material. Miniaturization of machine parts can be achieved. Moreover, since the dimensional accuracy of the raw material is high and the machining allowance by rough machining can be reduced, the machining cost can be suppressed, and inexpensive compressor parts can be provided.

  Although the present embodiment has been described by taking metal injection molding of stainless steel as an example, the same effect can be obtained even if die steel is used. Further, although this embodiment has been described by taking nitriding as an example, the same effect can be obtained by soft nitriding or ion nitriding.

なお、表１における記号の意味は以下のとおりである。
〇：良好な圧縮機用摺動部品の製作が可能
△：使用可能な圧縮機用摺動部品の製作が可能
×：圧縮機用摺動部品の製作が不可能 When sliding parts for a compressor were produced using alloy powders of various particle sizes as metal powder used in metal injection molding, the results shown in Table 1 were obtained.

The meanings of symbols in Table 1 are as follows.
○: Manufacture of good sliding parts for compressors △: Manufacture of usable sliding parts for compressors X: Manufacture of sliding parts for compressors is impossible

FIG. 3 is a perspective view of a scroll compressor incorporating the compressor sliding part according to the present invention.
As shown in FIG. 3, a bush 8 is fixed to the movable scroll 7, and a bush 10 is fixed to the bearing 9. These bushes 8 and 10 are very hard because they are mainly made of carbon. For example, it is obtained by impregnating and firing a polyamide resin or polyamideimide resin mixed with carbon or graphite on a jointly sintered bimetal, and since the main raw material is hard carbon or graphite and a soft resin, the surface hardness is low. Even during operation, the soft resin surface is recessed and hard carbon or graphite protrudes, which acts very hard on the sliding part. That is, the drive shaft 11 that is rotationally supported by the bush 10 and the compla bush 1 that is rotationally supported by the bush 8 are required to have high surface hardness.

  In order to satisfy this requirement, the drive shaft 11 is subjected to finish machining by roughing and then nitriding steel nitride, and the surface hardness is about Hv 900 to 1000. The plastic bush 1 has an outer diameter of 16 mm and a length of 17 mm. The surface hardness of the plastic plastic bushing is about Hv 1200 to 1300 by performing a nitriding treatment after rough machining of a stainless steel metal injection molded product and further finishing. It has become. With this combination, the reliability of the drive shaft 11 and the bush 10, the complaser bush 1 and the bush 8 can be ensured.

  Similarly, when the composite bush 1 is used after roughing and nitriding after a hot forged product of nitrided steel, the hardness of the outer diameter is about Hv 900 to 1000, and the outer diameter is the same. In order to ensure reliability even with millimeters, a total length of 19 millimeters was required. Further, when a stainless steel nitrided product is used for the complaser bush 1, each sliding surface has a different surface composition even if the drive shaft 11 is iron nitride and the complaser bush 1 is chromium nitride. Therefore, high reliability can be obtained without burning.

  In this embodiment, the sliding part that rotates and slides has been described as an example. However, the sliding part that reciprocally slides such as a vane provided in a rotary compressor or a cylinder that slidably holds the vane can be used. It is the same.

  In addition, although the present embodiment has been described by taking a scroll compressor as an example, by applying to a sliding part of various compressors such as a rolling piston compressor, a small, inexpensive and highly reliable compressor is realized. be able to.

(Embodiment 2)
In the present embodiment, the compressor component 1 shown in FIG. 1 is manufactured by powder compaction molding using stainless steel powder particles equivalent to SUS440C, and the inside and outside are 0.1 to 0.1 mm. After rough processing of about 0.3 millimeters, nitriding treatment is performed at a temperature of about 500 ° C. for about 6 hours, and then the inner and outer sides are finished by 20 to 100 micrometers. Note that the dense and adhesive strong oxide film on the surface of chromium-containing stainless steel or heat-resistant steel is removed using, for example, organic chloride, hydrogen fluoride, hydrogen sulfide, or the like.

  FIG. 4 is a hardness distribution curve of a sliding part for a compressor according to the present embodiment and a part obtained by performing nitriding treatment under the same conditions on a melted material of the same material. The vertical axis represents the micro Vickers hardness, and the horizontal axis represents the distance from the surface.

  As can be seen from FIG. 4, the hardness 5 after nitriding of the part manufactured by the green compact molding is increased by nearly 50 points compared to the hardness 6 of the part manufactured from the melted material of the same component. It can be seen that the depth of the hard part is shallow. This is because an alloy powder having a large particle size of 40 micrometers or more is used, so that the density increases only to about 85%, and the nitriding gas enters from the gap between the alloy powders, so that nitrogen is introduced from the outer periphery of the alloy powder. Since it penetrates and the whole powder becomes hard, it is considered that it becomes harder than a melted material having a density of 100%.

  In addition, the compacted sintered product has a lower hardness than the melted material because the surface area to be nitrided is large because nitrogen penetrates from the outer periphery of the alloy powder under the same nitriding conditions as the melted material. Therefore, it is considered that a large amount of nitrogen is consumed. In addition, it is easy to obtain a depth of hardness equivalent to that of the smelted material even if the green compact is formed by extending the time or adjusting the ammonia gas concentration. Can be easily realized.

  Furthermore, if the main purpose is to obtain a hard surface, the treatment may be performed under the same nitriding conditions as the melted material, which is economical. In addition, since higher hardness can be obtained by nitriding than melted material, the material is made using compacted green compacts and nitriding is performed to achieve miniaturization of compressor parts. Can do. Furthermore, since the dimensional accuracy of the material is high and the machining allowance by rough machining can be reduced, machining costs can be suppressed, and inexpensive sliding parts can be provided.

  Although the present embodiment has been described by taking the green compact sintering of stainless steel as an example, the same effect can be obtained even if die steel is used. Further, although this embodiment has been described by taking nitriding as an example, the same effect can be obtained by soft nitriding or ion nitriding.

なお、表２における記号の意味は以下のとおりである。
〇：良好な圧縮機用摺動部品の製作が可能
△：使用可能な圧縮機用摺動部品の製作が可能
×：圧縮機用摺動部品の製作が不可能 When sliding parts for a compressor were manufactured using alloy powders having various particle sizes as the powder used for the green compact sintering, the results shown in Table 2 were obtained.

The meanings of symbols in Table 2 are as follows.
○: Manufacture of good sliding parts for compressors △: Manufacture of usable sliding parts for compressors X: Manufacture of sliding parts for compressors is impossible

  According to the present invention, the surface hardness of the sliding component can be improved and sufficient wear resistance can be imparted, and the machining cost can be reduced with less machining allowance for rough machining. It can be manufactured at low cost, and can be applied not only to the composite bush but also to a normal bush, a shaft, and the like. In addition to the compressor, it is effective when used for sliding parts such as an engine.

It is a perspective view of the sliding component for compressors concerning Embodiment 1 or 2 of this invention. It is a hardness distribution curve of the sliding component for compressors concerning Embodiment 1 of this invention, and the component which performed the nitriding process on the same conditions on the molten material of the equivalent material. It is a perspective view of the scroll compressor incorporating the sliding component for compressors concerning this invention. It is a hardness distribution curve of the sliding component for compressors concerning Embodiment 2 of this invention, and the component which performed the nitriding process on the same conditions to the molten material of the equivalent material. It is a hardness curve after the nitriding process of the conventional sliding component for compressors.

Explanation of symbols

1 Sliding parts for compressors (Compla bush)
2 Hardness curve after firing and nitriding SUS420J2 3 Hardness curve of nitriding treatment of SUS410S molten material 5 Hardness curve of nitriding treatment of SUS440C compact sintered product 6 Hardness of nitriding treatment of SUS440C molten material Curve 7 Movable scroll 8, 10 Bush 9 Bearing 11 Drive shaft

Claims (4)

A method for manufacturing a sliding component, characterized in that a material is manufactured by metal injection molding using an alloy powder having a particle size of less than 30 micrometers, and nitriding is performed. A method for manufacturing a sliding part, characterized in that an alloy powder having a particle size of 40 micrometers or more is used to manufacture a raw material by green compact sintering and perform nitriding. A sliding part manufactured by the manufacturing method according to claim 1. 4. The sliding component according to claim 3, wherein the sliding component is a compressor bush that is rotatably supported by a bush fixed to the movable scroll in the scroll compressor.

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