JP2009228558A - Refrigerant compressor - Google Patents

Abstract

Provided is a highly reliable compressor having sufficient wear resistance even when a refrigerant having severe sliding conditions such as HFC or HCFC refrigerant is used.
In order to strengthen the base structure of a cylinder, the present invention provides a cast iron in which an alloy is added to precipitate carbide in the base of a eutectic graphite cast iron that does not contain an alloy. The cylinder material strengthened at the base ensures satisfactory sliding characteristics against sliding wear with various vane materials having higher hardness.
[Selection] Figure 1

Description

  The present invention relates to a refrigerant compressor used for commercial and household refrigeration air conditioning.

As a conventional refrigerant compressor, the cylinder is made of flake graphite cast iron or eutectic cast iron to which no alloy is added, and the vane inserted into the cylinder groove so as to be freely slidable is iron-based sintered, high-speed steel, Nitride steel, steel coated with ceramic coating (see, for example, Patent Document 1), and is operated at a high load by improving the reliability of the refrigerant compressor mechanism and improving the performance of the refrigerant compressor itself. It is inevitable to improve the reliability of compressor mechanical parts.
Japanese Patent Laid-Open No. 10-037876

  However, in recent years, sliding conditions for vanes, rollers, and cylinders have become stricter, and a combination of materials with better wear resistance has been required as the refrigerant has changed to R22 alternative refrigerant. A single material such as a special steel containing SKH or an iron-based sintered material used in a conventional vane has insufficient wear resistance. In addition, it cannot be said that the wear resistance is sufficient even with a single material such as special cast iron or iron-based sintered used in conventional rollers. Furthermore, even with flake graphite cast iron or eutectic graphite cast iron used in conventional cylinders, the wear resistance is insufficient.

  However, since the material of the vane itself has become harder than the conventional refrigerant compressor in recent years, the conventional cylinder material that is in a reciprocating sliding wear condition between the vane and the groove is highly reliable against frictional wear. It has become impossible to say, and it has become necessary to reinforce the material of the conventional cylinder.

  In order to strengthen the base structure of the cylinder, the present invention provides cast iron to which eutectic graphite cast iron that does not contain a conventional alloy is added with an alloy to precipitate carbide in the base. The cylinder material ensures satisfactory sliding characteristics against sliding wear with various vane materials having higher hardness.

  The cylinder of the present invention has a large process volume in the refrigerant compressor, the shaft has a large eccentricity, and the vane and the cylinder have a high sliding load, the base reinforced cylinder of the present invention is higher than the conventional product. This improves the reliability against sliding wear.

  The invention described in claim 1 is a eutectic graphite cast iron in which an alloy element of Ni 0.1 to 0.4%, Cr 0.4 to 1.0%, and Mo 0.1 to 0.4% is added to a cylinder. The base strengthening is improved by precipitating Cr or Mo carbide. Ni alone does not produce carbides, but improves wear resistance when combined with Cr or Mo.

  The invention described in claim 2 is a eutectic graphite cast iron in which Cr is added in an amount of 0.4 to 1.0% and Ni is added in an amount of 0.1 to 0.40% without adding Mo to the invention of claim 1 above. The base strengthening is improved by depositing Cr carbide in the base.

  The invention described in claim 3 adds 0.5 to 1.0% of Cu as a substitute for the effect of Ni to the invention of claim 2 above, strengthens the pearlite base in the base, and as a carbide generating element The eutectic graphite cast iron added with 0.2 to 1.0% of Cr achieves the same effect as the first or second aspect.

  The invention described in claim 4 is such that the pearlite in the base of the eutectic graphite cast iron cylinder material used in claims 1 to 3 is 10% or more.

  The invention described in claim 5 is a vane used in combination with a cylinder reinforced with a base used in claims 1 to 3 above, a steel material containing Cr, or a material obtained by nitriding the steel material Or a sintered material containing Cr.

  The inventions described in claims 6 and 7 are a refrigerant compressor in which the refrigerant is HFC and the refrigerating machine oil is ester or ether oil, and a highly reliable refrigerant compressor in which the refrigerant is HCFC and the refrigerating machine oil is mineral oil. Is.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(Embodiment 1)
A typical example of a conventional refrigerant compressor is a rotary refrigerant compressor. FIG. 1 is a longitudinal sectional view of a mechanism portion of a refrigerant compressor according to an embodiment of the present invention, and FIG. It is a cross-sectional view which shows a principal part.

  In FIG. 1 and FIG. 2, 1 is a sealed container, and an electric motor unit 2 and a refrigerant compression mechanism unit 3 are arranged. The electric motor unit 2 includes a rotor 2a and a stator 2b, and a shaft 8 rotatably supported by a main bearing 9 and a sub bearing 10 is fixed to the rotor 2a by a method such as press fitting. The refrigerant compressor unit 3 includes a cylinder 20 having a suction hole 5 and a radial cylinder groove 23, a roller 7 that rotates eccentrically while sliding the outer peripheral surface on the inner peripheral surface of the cylinder 20, and the inner peripheral surface of the roller 7. The shaft 8 is slidably inserted into the shaft 8 and is reciprocally slidably accommodated in the cylinder groove 23, and the tip is pressed against the roller 7 by the pressing force and back pressure (discharge pressure) by the spring 24. A vane 21 that divides a cylinder internal space into a suction chamber 25 and a compression chamber 26, and a main bearing 9 and a sub-bearing 10 that seal both ends of the cylinder are configured.

  Next, the operation of the rotary refrigerant compressor according to this configuration will be described. When the motor unit 2 is energized from the outside, the rotor rotates and the shaft 8 is rotationally driven. When the shaft 8 rotates, the roller 7 slidably attached to the eccentric portion performs a planetary motion (counterclockwise rotation in FIG. 2) while slidingly contacting the cylinder inner peripheral surface. As a result, refrigerant gas such as HFC is sucked into the suction chamber 25 from the suction pipe 4 through the suction hole 5, and at the same time, the refrigerant gas whose pressure is increased in the compression chamber 26 passes through the discharge hole 6 through the discharge hole 6 and is sealed. 1 is discharged.

  At this time, the vane 21 that divides the suction chamber 25 and the compression chamber 26 is pressed against the outer peripheral surface of the roller 7 by the pressure applied to the spring 24 and the back of the vane, and the tip portion is the outer peripheral surface of the roller 7 and the side portion is the cylinder. It will slide with the inner wall surface of the groove 23. Lubrication of the vane 21, the roller 7, and the cylinder groove 23 is performed using the lubricating oil 12 stored in the bottom of the sealed container in a steady operation state, but there is not enough lubricating oil in the sliding portion at the time of starting. The lubricating oil 12 slightly contained in the sucked refrigerant gas (the lubricating oil is slightly discharged together with the refrigerant gas from the refrigerant compressor, circulates through the refrigeration cycle, and then returns to the refrigerant compressor from the suction pipe 4. Come back) will be used.

  The vane 21 has recently been used as a high-speed sintered product, high-speed steel, or a material obtained by nitriding high-speed steel. As described above, the sliding condition at the start of the hermetic rotary refrigerant compressor is lubrication. It can be said that the sliding conditions are more severe because the oil film is difficult to be formed because reciprocating motion is caused between the vane and the cylinder groove. Accordingly, the wear resistance of the flake graphite cast iron or eutectic graphite cast iron material that does not include a conventional alloy is insufficient. Moreover, since the HFC refrigerants employed for environmental measures in recent years have poor lubricity, it can be said that the sliding conditions of the rotary refrigerant compressor using the HFC refrigerant are particularly severe.

  In the conventional invention, as shown in the metal structure of the cylinder in FIG. 3, the matrix is a mixed structure of pearlite / ferrite, but in the metal structure of the cylinder of the present invention, carbide is precipitated in the matrix of pearlite / ferrite. As a result, the base is strengthened and the macro hardness is increased. In recent years, sufficient wear resistance has been ensured even when sliding with a vane material having improved hardness.

  The cylinder according to the present invention can supply the vane and the cylinder groove with no problem even under severe operating conditions under HFC refrigerant conditions. Since it does not change, it is provided as a more reliable refrigerant compressor material.

The longitudinal cross-sectional view which shows the rotary refrigerant compressor in embodiment of this invention The cross-sectional view which shows the principal part of the refrigerant compressor in embodiment of this invention Micrographs comparing metal structures of conventional and inventive cylinders

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Airtight container 2 Electric motor part 3 Refrigerant compressor part 4 Suction pipe 5 Suction hole 6 Discharge hole 7 Roller 8 Shaft 9 Main bearing 10 Sub bearing 11 Refrigerating machine oil 20 Cylinder 21 Vane 22 Discharge notch
23 Cylinder groove 24 Spring 25 Suction chamber 26 Compression chamber

Claims (7)

A rotary refrigerant compressor comprising: a cylinder; a roller that rotates eccentrically in a cylinder by a shaft; and a vane that is slidably in contact with the roller inserted and retracted into a groove formed in a radial direction of the cylinder. In order to ensure wear resistance between the groove and the vane, the cylinder is a mold in which an alloy element of Ni 0.1 to 0.4%, Cr 0.4 to 1.0%, Mo 0.1 to 0.4% is added. A refrigerant compressor characterized in that it is composed of a eutectic graphite cast iron cast by casting or sand mold casting and having carbides deposited in the base. In a rotary refrigerant compressor comprising a cylinder, a roller that rotates eccentrically in a cylinder by a shaft, and a vane that is slidably in contact with the roller inserted and retracted into a groove formed in a radial direction in the cylinder, the cylinder includes: It is composed of eutectic graphite cast iron cast by die casting or sand casting added with alloy elements of Cr 0.4-1.0%, Ni 0.1-0.4%, and carbides precipitated in the base. A refrigerant compressor characterized by that. In a rotary refrigerant compressor comprising a cylinder, a roller that rotates eccentrically in a cylinder by a shaft, and a vane that is slidably in contact with the roller inserted and retracted into a groove formed in a radial direction in the cylinder, the cylinder includes: It was composed of eutectic graphite cast iron cast by die casting or sand casting added with alloy elements of Cr 0.2-1.0% and Cu 0.5-1.0%, with carbides precipitated in the matrix. A refrigerant compressor characterized by that. The refrigerant compressor according to any one of claims 1 to 3, wherein a pearlite ratio of the eutectic graphite cast iron of the cylinder is 10% or more. 4. The refrigerant compressor according to claim 1, wherein the vane is a steel material containing Cr, a steel containing Cr subjected to nitriding treatment, or a sintered alloy containing Cr. 5. . The refrigerant compressor according to any one of claims 1 to 5, wherein the refrigerant is HFC and the refrigerating machine oil is ester or ether oil. The refrigerant compressor according to any one of claims 1 to 5, wherein the refrigerant is HCFC and the refrigerating machine oil is mineral oil.