JP2005127151A - Component for compressor and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a component for a compressor capable of forming a minute oil sump by forming the surface of the component for the compressor into a mixing face having different hardness to improve oil holding property when operating the component for the compressor and eliminate troubles such as seizure and achieving reduction of input and long service life and having high reliability. <P>SOLUTION: A raw material is molded by pressure fine particle sintering molding using iron alloy powders containing Cr, and nitriding treatment excluding carburized component is applied to form the surface having a mixing texture 3 composed of a compound layer 2 of Fe-Cr-N, a diffusion layer of Fe-Cr-N, and a base. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a compressor component having increased hardness by nitriding and a method for manufacturing the same.

  A vane provided in a rotary compressor or the like is slidably attached to a vane groove formed in a cylinder, and the side surface of the vane is in sliding contact with the side wall of the vane groove and the tip of the vane is in sliding contact with the roller. Wear resistance is required. Therefore, steel containing chromium, sintered alloy or cast iron is used as a base material, the base material is soft-nitrided, and a first compound layer of Fe—Cr—N is formed on the surface layer. A structure in which a second compound layer made of the same component is formed below the compound layer has been proposed (see, for example, Patent Document 1).

  In addition, a material in which a nitrided layer is formed by nitriding the surface of a stainless steel base material has been proposed (see, for example, Patent Document 2).

  Furthermore, after the sintered iron having a porosity of 10% or less or 15% or less using a material of an iron-based powder material is quenched and tempered to make the base a martensite structure, the surface is subjected to nitriding or soft nitriding treatment Some have a compound layer made of Fe—N and a nitrogen diffusion layer formed inside (see, for example, Patent Document 3 or 4).

JP-A-60-26195 JP-A-11-101189 Japanese Patent Laid-Open No. 2001-140782 JP 2001-342981 A

  However, in the above conventional configuration, the surface is formed of an Fe—Cr—N or Fe—N compound layer or an Fe—Cr—N diffusion layer, and the surface has a single composition and a uniform hardness. Therefore, minute wear of wear-resistant parts such as vanes generated when the compressor is operated is uniform. As a result, it was difficult to maintain a predetermined oil retaining property on the surface, and there was a risk of seizing.

  In addition, from the viewpoint of securing lubricity (securing oil retention and oil film), conventionally, it has been common to select lubricating oil with a certain degree of viscosity. However, if lubricating oil with a high viscosity is selected, On the other hand, the viscosity of the lubricating oil, on the other hand, became a flow resistance load, affecting the input of the compressor (the input increased).

  In addition, if a high-viscosity lubricating oil is used, during the initial start-up of the compressor in winter, etc., the lubricating oil will stagnate (the viscosity of the lubricating oil will be higher than at normal temperature (difficult to flow) and will not reach the sliding part sufficiently. ) ”Is likely to occur.

  The present invention has been made in view of the above-described problems of the prior art, and forms a small oil sump by making the surface of a compressor component a mixed surface having different hardness, and the compressor Highly reliable compressor parts that can improve oil retention when operating parts, eliminate defects such as seizure, and achieve low input and long service life. It is intended to provide.

  In order to achieve the above object, the compressor part according to claim 1 of the present invention is formed by compacting a material by compaction sintering using an iron-based alloy powder containing Cr, and carburizing. A nitriding treatment is applied to remove components, and the surface is a mixed structure of a Fe—Cr—N compound layer, a Fe—Cr—N diffusion layer, and a matrix.

  Further, the invention according to claim 2 is a method in which a raw material is formed by compaction sintering using an alloy powder containing at least one metal element of Mn, Ti, and V as an iron-based alloy powder containing Cr. It is formed and subjected to nitriding treatment excluding the carburized component, and the surface is a mixed structure of a Fe—Cr—N compound layer, a Fe—Cr—N diffusion layer, and a matrix.

  Furthermore, the invention according to claim 3 is characterized in that there are holes on the surface, the Fe—Cr—N compound layer in the vicinity of the holes, and the Fe—Cr—N diffusion layer and the base as the distance from the holes increases. It is characterized by having a mixed structure.

  According to a fourth aspect of the present invention, a material is formed by compaction sintering using an iron-based alloy powder containing Cr, a nitriding treatment is performed to eliminate carburizing components, and the surface is Fe-Cr. It is characterized by being a mixed structure of a -N compound layer, a Fe-Cr-N diffusion layer, and a sorbite base structure.

  Further, the invention according to claim 5 is characterized in that there are vacancies on the surface, an Fe—Cr—N compound layer in the vicinity of the vacancies, and an Fe—Cr—N diffusion layer and sorbite as they move away from the vacancies It is a mixed organization with the organization base.

  The invention according to claim 6 is characterized in that the compressor component is a vane.

  According to a seventh aspect of the present invention, there is provided a method for manufacturing a compressor component, comprising forming a material by compacted green compacting, quenching and tempering, and then performing nitriding treatment to remove a carburizing component. The surface is subjected to removal processing, and the surface has a mixed structure including at least a Fe—Cr—N compound layer.

Since the present invention is configured as described above, the following effects can be obtained.
The raw material is formed by the green compact sintering method using an iron-based alloy powder containing Cr or an iron-based alloy powder containing Cr containing an alloy powder containing at least one metal element of Mn, Ti, and V. However, the nitriding treatment that does not contain carburizing components is applied, and the surface is a mixed layer of compound layer, diffusion layer, and base, so when finishing the compressor parts, the processing amount of the soft base part increases, A small dent will be formed to form an oil reservoir, and further operation of the compressor parts will cause a slight wear on the soft base and form an oil reservoir. High compressor parts can be realized.

  When an alloy powder containing at least one metal element of Mn, Ti, and V is used for the iron-based alloy powder containing Cr, at least one of Cr, Mn, Ti, and V is used for the compound layer and the diffusion layer. Since two components are contained, after ensuring a predetermined hardness with Fe and Cr, the hardness is further improved by the presence of Mn, the nitriding treatment is promoted by the presence of Ti, or V Since the nitriding depth can be increased by the presence, the reliability of the compressor component is further improved.

  Furthermore, after forming the material by green compact sintering using iron-based alloy powder containing Cr, quenching and tempering, nitriding treatment without carburizing component is performed, and the surface is a compound layer Because of the mixed structure of the base structure of the diffusion layer and sorbite, when finishing the compressor parts, the processing amount of the soft base part increases, and a small depression is formed to form an oil reservoir. . Further, when the compressor parts are operated (relative frictional motion), the soft base portion is slightly worn compared to the compound layer and the diffusion layer, and becomes an oil reservoir. Furthermore, since the base structure is hardened by quenching and tempering, the compound layer and the diffusion layer become harder due to nitriding, and it is possible to realize a highly reliable compressor part with higher wear resistance without seizing. .

  Also, after forming the material by green compact sintering, quenching and tempering, nitriding treatment without carburizing component is performed, and removal processing is performed on a part of the surface, so that the surface is Fe-Cr Not only the -N compound layer but also a surface with hardness variation. Therefore, when finishing, the amount of processing of the soft base portion is increased, and a minute depression is formed to form an oil reservoir. In addition, during operation (relative frictional motion), the soft part generates minute wear, which becomes an oil reservoir and improves lubricity, and the wear resistance can be maintained in the other compound layer part. The reliability of machine parts can be improved.

  Furthermore, if a lubricating oil pool is formed in the compressor part and the lubricity of the sliding portion is improved, the choice of the type of lubricating oil (refrigerating machine oil) to be injected into the compressor increases. In addition, since the reservoir of compressor oil is randomly and innumerably formed, the lubricity (oil retention and oil film) is easily secured, and low viscosity (smooth) lubricating oil can be used. . Therefore, the flow resistance load due to the viscosity of the lubricating oil is also reduced, and a low input of the compressor can be achieved.

  Further, since the lubricating oil is smoothly circulated, the problem of “sleeping” at the initial start-up of the compressor in winter can be easily solved.

  Furthermore, as the sliding of the sliding portion progresses due to the long-term use of the compressor, the lubricating oil pool is gradually formed and the above-described functions gradually increase, leading to longer life and improved reliability of the compressor. Is.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
The compressor component according to the present invention is used as a sliding member such as a vane provided in a rolling piston compressor, for example, and contains Cr such as powder high speed (powder high speed steel). After performing vacuum sintering on the iron-based alloy powder at a temperature of about 1200 ° C., quenching is performed to obtain a martensite structure, and tempering heat treatment is performed at 480 ° C. to 580 ° C. to form a sorbite structure. The gas nitriding treatment was performed at 400 ° C., which is equal to or lower than the tempering temperature, for about 6 hours.

  FIG. 1 shows a cross-sectional structure after nitriding of a compressor component according to the present invention manufactured as described above. After gas nitriding, etching is performed to make the compound layer easy to see.

  Since the material is manufactured by green compact molding, the density increases only to about 80-90%, there are many holes 1 and the gas used for the nitriding treatment passes through the holes 1 Nitriding is performed until a white compound layer 2 is formed around the pores 1. Further, as the distance from the hole 1 increases, the black portion 3 increases, which is a mixed structure of the diffusion layer and the base.

  FIG. 2 shows the compressor part cut in a direction perpendicular to the plane of FIG. 1 (that is, cut at a predetermined depth from the surface), and the surface of the cut surface is magnified 450 times. It is.

  As shown in FIG. 2, there is a hole 1 peculiar to a green compact molded product on the ground surface, and nitriding proceeds in the periphery of the hole 1. The -N compound layer 2 is etched to have a white color. In addition, the white color is reduced away from the surface of the hole 1, and the mixed structure 3 of the diffusion layer of Fe—Cr—N and the base is formed. That is, the surface of the compressor part having the pores 1 is a mixed structure 3 of the compound layer 2, the diffusion layer, and the base structure.

  FIG. 3 is a photograph of an indentation whose cross section was measured by micro Vickers hardness, and shows that the smaller the indentation, the harder the micro Vickers hardness. As apparent from the size of the micro Vickers indentation, the periphery of the hole 1 is relatively small, and the size of the micro Vickers indentation 8 between the holes 1 and 1 is larger than that of the periphery of the hole. It can be seen that the hardness is reduced. This is because the nitriding gas enters the periphery of the pores 1 to form the compound layer 2, and the space 8 between the pores 1 and 1 is the mixed structure 3 of the diffusion layer and the base. It is considered that it is lower than the periphery of the hole 1.

  Since the hardness of the surface varies moderately in this way, when finishing the compressor parts, the amount of processing of the soft base portion increases, and a small depression is formed to form an oil reservoir. . In addition, when the compressor parts are activated, a slight wear occurs in the soft base tissue part, which acts as a sump, and in addition to the pores of the green compact, the wedge effect A high oil sump is formed over the entire movable part. Therefore, the entire surface has improved oil retention and good lubricity, and wear resistance can be ensured by the compound layer and diffusion layer around the pores, so it has better reliability compared to compressor parts with a hard entire surface. Sex can be secured.

  Although the present embodiment has been described with the quenching and tempering of powder high speed steel, the material may be manufactured with a general alloy powder, and Mn, Ti may be added to the iron-based alloy powder containing Cr. The same effect can be obtained even when manufactured with an alloy powder containing at least one metal element of V.

  FIG. 4 shows a hardness distribution curve of the compressor component of FIG. 1 after nitriding, and the hardness is almost the same as the surface B even at a position A exceeding 0.4 mm from the surface. When the surface C of the compressor part is ground and removed by about 0.1 mm and the position C having a depth of 0.1 mm from the surface is etched, the cross-sectional structure of FIG. 2 is obtained.

  In this way, even if the powdered high-speed green compact is subjected to nitriding for a short time, since the material has pores, the nitriding gas easily penetrates into the inside and is deeply nitrided. Therefore, in the normal nitriding treatment, it is necessary to perform a nitriding treatment after roughing the material, and then to perform a finishing process. On the other hand, in the powder high-speed sintered compact, the material is subjected to nitriding treatment. Even if direct finishing is performed, the required hardness can be easily obtained. Furthermore, even if deformation due to quenching and tempering of the material occurs and the machining allowance becomes non-uniform, variation in the surface hardness of the hardest compound layer of the finished product can be reduced because it is deeply nitrided. .

  Furthermore, by removing the surface, not only the compound layer of Fe—Cr—N but also the diffusion layer of Fe—Cr—N and the mixed structure of the matrix appear. It can be understood from the existence of the low part. That is, the compressor component according to the present invention can be manufactured at low cost because the rough machining step can be omitted while maintaining excellent wear resistance.

  FIG. 5 is a perspective view of a vane 9 of a rolling piston compressor that is an example of a compressor component according to the present invention.

  The vane 9 was manufactured by a green compact molding method using powder high speed steel, and was subjected to quenching and tempering heat treatment in a raw material state, and the base had a sorbite structure. This material was subjected to nitriding treatment (in an atmosphere in which no CO was present) excluding carburizing components, and when nitriding gas was infiltrated into the inside through the pores characteristic of the green compact sintering method, Even when the thickness exceeded 4 mm, the hardness distribution was the same as that on the surface.

  In addition, the dimensional tolerance of the vane material manufactured by the green compact sintering method and subjected to heat treatment such as vacuum sintering, quenching, and tempering is ± 0.05mm or less, and the parallelism, flatness, contour in the range Shape accuracy such as degrees varies. Even if a nitriding treatment is performed on such a material at a temperature of 400 ° C. for 4 hours, since the change of each dimension and shape accuracy is about 0.02 mm, it is sufficient to set the machining allowance to 0.08 mm. .

  Therefore, the surface of the vane material after nitriding was ground by about 0.08 mm to expose the compound layer, the diffusion layer, and the base structure around the voids appearing on the surface. These compound layers, diffusion layers, and matrix structures have hardnesses of about mHv 1100, 950, and 800, respectively, and wear resistance can be maintained in the mHv 1100 compound layer portion. The other diffusion layers and the matrix structure are slightly worn at the beginning of operation, and the pores become a reservoir of lubricating oil, so that very high reliability can be obtained. In addition, since it is not necessary to perform roughing, an inexpensive and highly reliable vane can be provided.

  In this embodiment, the vane of the rolling piston compressor is used, but it may be used for other parts, and it can also be used for sliding parts of various compressors such as a scroll type.

  When finishing the compressor component according to the present invention, the amount of processing of the soft base portion is increased, and a minute recess that becomes an oil reservoir is formed, and further, the soft base portion is slightly worn. Since an oil reservoir is formed, wear resistance is improved and seizure does not occur, and it is effective when used for a sliding part of a compressor.

It is a cross-sectional etching photograph of the components for compressors concerning this invention. It is the etching photograph of the surface which grinded off the surface of the components for compressors of FIG. It is a photograph of the micro Vickers hardness measurement impression of the surface of the components for compressors of FIG. It is a hardness distribution curve of the components for compressors of FIG. It is a perspective view of the vane which is an example of the components for compressors concerning the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Hole 2 Compound layer 3 Mixed structure 8 Micro Vickers indentation between holes 9 Vane

Claims (7)

A raw material is formed by compacting by using green-based alloy powder containing Cr, nitriding treatment is performed to eliminate carburizing components, and the surface is formed of a Fe—Cr—N compound layer and Fe—Cr—N. A component for a compressor characterized by having a mixed structure of a diffusion layer and a base. A material is formed by compaction sintering using an alloy powder containing at least one metal element of Mn, Ti, and V in an iron-based alloy powder containing Cr, and nitriding treatment is performed by eliminating carburizing components. A component for a compressor, wherein the surface is a mixed structure of a Fe—Cr—N compound layer, a Fe—Cr—N diffusion layer, and a matrix. There are vacancies on the surface, and the vicinity of the vacancies is an Fe—Cr—N compound layer, and as the distance from the vacancies, the mixed structure of the Fe—Cr—N diffusion layer and the base is formed. The compressor part according to claim 1 or 2. A raw material is formed by compacting by using green-based alloy powder containing Cr, nitriding treatment is performed to eliminate carburizing components, and the surface is formed of a Fe—Cr—N compound layer and Fe—Cr—N. A component for a compressor characterized in that it is a mixed structure of a base layer of sorbite and a sorbite diffusion layer. There are vacancies on the surface, and the vicinity of the vacancies is an Fe—Cr—N compound layer, and as it is away from the vacancies, the mixed structure of the Fe—Cr—N diffusion layer and the base of the sorbite structure is used. The compressor component according to claim 4, wherein the compressor component is a compressor component. The compressor part according to any one of claims 1 to 5, wherein the compressor part is a vane. After forming the material by green compact sintering, quenching and tempering, it is subjected to nitriding treatment that excludes carburizing components, and removal processing is performed on a part of the surface, and the surface is a compound of at least Fe-Cr-N The method for manufacturing a compressor part according to any one of claims 1 to 6, wherein the mixed structure includes a layer.

Images