JP2011047286A - Refrigerant compressor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a bearing material securing sufficient abrasion resistance in a compressor employing a material of a grade having a slight ferrite phase in the matrix of nodular graphite cast iron for a crankshaft or an alloy impregnated die eutectic graphite cast iron for the crankshaft and having a matrix formed of a ferrite matrix. <P>SOLUTION: The compressor is formed to prevent the sticking of a crankshaft 8 made of nodular graphite cast iron or alloy impregnated die eutectic graphite cast iron and ferrite matrix of the crankshaft by being almost pearlitized through the suppression of the occurrence of a ferrite of a matrix structure in a bearing so as to secure abrasion resistance between the crankshaft 8 and a main bearing 9 and auxiliary bearing 10. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

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

  As a conventional refrigerant compressor, a crankshaft that transmits the power of the compressor is made of a material in which an alloy is added to flake graphite cast iron (alloyed gray cast iron). On the other hand, crankshafts made of spheroidal graphite cast iron or alloyed die-eutectic graphite cast iron having higher rigidity than flake graphite have been used.

  While the base structure of the crankshaft is mostly pearlite with conventional alloyed gray cast iron, spheroidal graphite cast iron with improved rigidity is a mixture of pearlite and ferrite. Since the base is basically made of ferrite, material management is required for wear resistance with the bearing.

JP 2009-97429 A

  However, in the conventional alloyed gray cast iron crankshaft, the base is almost pearlite but its rigidity is low, so it was difficult to design with high efficiency, but the crank of spheroidal graphite cast iron or alloyed eutectic graphite cast iron was difficult. With shafts, high efficiency is easy because high rigidity is ensured, but organizationally, since ferrite is contained in the base, there is a problem that it is necessary to ensure wear resistance with the bearing material. Had.

  The present invention solves the problem of ensuring wear resistance in a compressor using a crankshaft containing a large amount of ferrite in the base, and provides a bearing material having sufficient wear resistance with the crankshaft. The purpose is to do.

  In order to solve the above-described conventional problems, the gray cast iron main bearing of the present invention manages and achieves the content of Mn (manganese) so that the phase in the base is pearlite.

  In addition, the secondary bearing, which is iron-based sintered of the present invention, controls the content of C (carbon) so as to reduce the ferrite in the matrix and make it almost a eutectoid pearlite matrix.

  This prevents the occurrence of galling with the ferrite phase of the crankshaft.

  By making the base structure of the main bearing or the sub-bearing of the present invention pearlite, sliding resistance and wear resistance with the crankshaft are ensured.

The longitudinal cross-sectional view which shows the rotary compressor to which this invention is applied Cross section showing the main part of the mechanism of the rotary compressor Microstructure picture of main bearing upper part in conventional embodiment Microstructure photograph of main bearing upper part in embodiment of this invention Microstructure picture of secondary bearing in the conventional embodiment Microstructure photograph of sub bearing in embodiment of this invention

  In the first invention, the main bearing for supporting the rotation of a crankshaft made of spheroidal graphite cast iron having a base of 50% or more of pearlite and having a remaining ferrite structure, or an alloyed mold eutectic graphite cast iron having a base made of ferrite is used. Cast iron, especially because the upper part (boss hole) of the main bearing is thin, so it is easy to be cooled rapidly during casting, and the graphite itself is eutectic graphite unlike other parts, and the base tends to become ferritic. Since sliding with the crankshaft containing ferrite tends to cause galling between ferrites and lowers wear resistance, the Mn amount of cast iron is set so that a pearlite base can be secured almost even in the boss upper structure where the main bearing is easily cooled. By setting the content within the range of 0.7 to 1.0%, it is possible to ensure wear resistance with the crankshaft.

  In the second invention, the auxiliary bearing supporting the rotation of the crankshaft described in the first and second inventions is an iron-based sintered part, and the C amount is set to 0. 7% to 1.1% of eutectoid component and the base is almost pearlite to ensure wear resistance with the crankshaft having the ferrite phase and to improve the reliability around the compressor shaft. Can do.

  According to a third aspect of the present invention, even if the refrigerant is HCFC or HFC refrigerant conditions with stricter lubrication conditions, the wear resistance between the crankshaft and the bearing is ensured by securing the pearlite of the bearing base structure according to any one of the first to third aspects. Thus, the reliability of the compressor can be ensured.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the present invention is not limited to the embodiments.

(Embodiment 1)
FIG. 1 is a longitudinal sectional view of a rotary compressor to which the present invention is applied, and FIG. 2 is a transverse sectional view showing an essential part of a mechanism of the compressor.

  In FIG. 1, reference numeral 1 denotes a sealed container, in which an electric motor unit 2 and a compression mechanism unit 3 are arranged. The electric motor unit 2 includes a rotor 2a and a stator 2b, and a crankshaft 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 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 an outer peripheral surface on the inner peripheral surface of the cylinder 20, and an inner peripheral surface of the roller 7. The eccentric part of the crankshaft 8 inserted slidably and the cylinder groove 23 are housed slidably in a reciprocating manner, and the tip part is pressed against the roller 7 by the pressing force and back pressure (discharge pressure) by the spring 24. A vane 21 that divides the internal space of the cylinder 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 compressor will be described. When the motor unit 2 is energized from the outside, the rotor rotates and the crankshaft 8 is rotationally driven. When the crankshaft 8 rotates, the roller 7 slidably attached to the eccentric portion performs planetary motion (counterclockwise rotation in FIG. 2) while slidingly contacting the inner peripheral surface of the cylinder. 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.

  In FIG. 1, the position of the discharge hole 6 is depicted at a position away from the suction hole for the sake of clarity, but in reality, it is disposed near the suction hole 5 with the vane 21 interposed therebetween as shown in FIG. 2. .

  At this time, the vane 21 that divides the suction hole 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 portion of the vane, the tip portion is the outer peripheral surface of the roller 7, and the side surface 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 refrigerating machine oil 12 stored in the bottom of the hermetic container in the steady operation state, but there is not enough refrigerating machine oil in the sliding part at the time of starting. Refrigerating machine oil 12 slightly contained in the sucked refrigerant gas (refrigerant oil is slightly discharged from the compressor together with the refrigerant gas, circulates through the refrigeration cycle, and then returns to the compressor from the suction pipe 4 again. Come) will be used.

  In the conventional rotary compressor, the crankshaft 8 has been used in spite of recent high-efficiency movements such as high-efficiency spheroidal graphite cast iron or alloyed mold eutectic graphite cast iron. In addition, the sliding condition at the start of the hermetic rotary compressor is a severe condition in which the lubricating oil is not sufficiently supplied. In particular, an oil film is formed between the crankshaft 8, the main bearing 9, and the sub-bearing 10 because of rotational movement. It can be said that it is a more severe sliding condition because it is hard to be done. In addition, since the HFC refrigerant adopted for environmental measures in recent years has poor lubricity, it can be said that the sliding condition of the rotary compressor using the HFC refrigerant is particularly severe.

  FIG. 3 shows an upper structure of the main bearing boss in the conventional embodiment, and it can be seen that the base is easily converted to ferrite (white) because it is rapidly cooled.

  On the other hand, FIG. 4 shows the boss superstructure of the main bearing in the present invention (management of the amount of Mn). The base has few ferrite (white) and is almost pearlite (gray / striped in the photograph). I understand.

  FIG. 5 shows the structure of the secondary bearing of the iron-based sintered component in the conventional embodiment, and the base is a mixture of pearlite but ferrite.

  On the other hand, FIG. 6 shows the structure of the sub-bearing in the embodiment of the present invention, which is a sub-bearing in which the C amount is controlled within the range where pearlite is deposited, and it can be seen that the base is almost pearlite.

  As described above, by making the base of the main bearing and the sub-bearing pearlite, it is possible to improve the wear resistance of the crankshaft including the ferrite phase in the base.

  On the other hand, when the crankshaft is an alloyed gray cast iron that has been used in the past, the base structure is almost pearlite, but when the mating bearing material is a conventional base structure and contains some ferrite, the reliability around the crankshaft and the bearing Therefore, by improving the base in the present invention, the reliability and safety of the compressor itself are improved.

DESCRIPTION OF SYMBOLS 1 Airtight container 2 Electric motor part 3 Compressor part 4 Suction pipe 5 Suction hole 6 Discharge hole 7 Roller 8 Shaft 9 Main bearing 10 Sub bearing
11 Clamping bolt 12 Refrigeration machine oil 20 Cylinder 21 Vane 22 Discharge notch 23 Cylinder groove 24 Spring 25 Suction chamber 26 Compression chamber

Claims (3)

The main bearing that directs rotation of spheroidal graphite cast iron crankshaft with a pearlite area ratio of 50% or more and a base structure of the remaining ferrite, or an alloy-molded eutectic graphite cast iron crankshaft whose base is made of ferrite is gray cast iron. In particular, the refrigerant compressor is characterized in that the Mn content is in the range of 0.7 to 1.0% so that the structure of the upper part of the main bearing becomes a pearlite base. The secondary bearing for instructing the rotation of the crankshaft is an iron-based sintered product, and the C content is in a range of 0.7 to 1.1% so that the base structure is pearlite. 1. The refrigerant compressor according to 1. The refrigerant compressor according to claim 1 or 2, wherein the refrigerant is HCFC and the refrigerating machine oil is mineral oil, or the refrigerant is HFC and the refrigerating machine oil is ester or ether oil.