JP2005299771A - Rolling bearing - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a rolling bearing having a longer life independently of lubricating conditions. <P>SOLUTION: A thrust needle bearing 10 comprises a shaft bearing washer (an inner ring) 11, a housing bearing washer (an outer ring) 12, and a plurality of rollers 13 as rolling elements arranged between an inner ring raceway 11a of the shaft bearing washer 11 and an outer ring raceway 12a of the housing bearing washer 12 in a peripheral rolling manner. Nitride layers are provided on the rolling surfaces of the rollers 13 and the raceway surfaces of the inner ring raceway 11a and the outer ring raceway 12a with their nitrogen concentrations of 0.1-0.3%. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a rolling bearing suitably used for an air conditioner, a car air conditioner, a water heater compressor, and the like.

  Conventionally, various compressors are used in air conditioners, car air conditioners, or hot water heaters. Here, as one type of compressor, a variable capacity type car air conditioner compressor will be described as an example, and the structure thereof will be described below.

As shown in FIG. 1, a variable capacity type car air conditioner compressor has a drive shaft 2 rotatably inserted in a housing 1 and a swash plate 3 connected to the drive shaft 2 in a variable inclination angle. A wobble plate 4 is slidably attached to the plate 3. A thrust bearing 5 is disposed between the swash plate 3 and the wobble plate 4. One end of a plurality of piston rods 6 is attached to the wobble plate 4 at equal intervals in the circumferential direction, and the other end of the piston rod 6 is connected to the piston 7. The piston 7 is provided so as to slide inside a cylinder 1a provided in the housing 1, and compresses and discharges the refrigerant gas flowing into the bore of the cylinder 1a. That is, when the swash plate 3 rotates, the wobble plate 4 performs a so-called razor-like operation, reciprocates the piston 7 in the axial direction via the piston rod 6, and compresses and discharges the refrigerant gas. (For example, refer to Patent Document 1).
JP 2003-294034 A (page 2-3, FIG. 1)

  By the way, during operation of the compressor, the drive shaft 2 receives a force in the thrust direction via the swash plate 3, so that a thrust bearing that supports the drive shaft 2 in the thrust direction with respect to the housing 1 is necessary. Such a thrust bearing is connected to the drive shaft 2 and arranged on the pulley unit side that receives the amount of rotation from the belt. However, the thrust bearing is at a position far from the supply source of the lubricating oil supplied in the form of a mist. There was a risk that it would be difficult to form an oil film between the rolling surface of the rolling element and the raceway surface of the inner and outer rings.

  As a phenomenon peculiar to the compressor, when the refrigerant is sealed, the oxygen concentration in the system is lowered in order to exhaust the atmosphere in the circulation system (of the refrigerant). In a rolling bearing, when oil film formation is insufficient, contact portions such as the rolling surfaces of the rolling elements and the raceway surfaces of the inner and outer rings are brought into metal contact by the oil film breakage. At this time, if the oxygen concentration in the circulatory system is sufficient, an oxide film is formed on the surface of the rolling or raceway surface, preventing further metal contact and self-healing to suppress adhesion wear. However, when the oxygen concentration is low, surface oxidation is unlikely to occur, so once the rolling contact surface and the raceway contact each other, the contact between metals will always be repeated, and adhesive wear will stop. There was a risk of progress.

  This invention is made | formed in view of the said situation, Comprising: It aims at providing the rolling bearing which can ensure long life irrespective of lubrication conditions.

  In order to achieve the above-described object, the rolling bearing according to the present invention is characterized by the following (1) to (3).

(1) An outer ring provided with an outer ring raceway, an inner ring provided with an inner ring raceway, and a plurality of rolling elements arranged so as to be freely rollable in the circumferential direction between the outer ring raceway and the inner ring raceway. A rolling bearing provided,
At least one of the raceway surfaces of the outer ring raceway and the inner ring raceway and the rolling surface of the rolling element has a nitride layer,
The nitrogen concentration of the nitride layer is 0.1% or more.

(2) The rolling bearing according to (1) above,
The nitrogen concentration of the nitride layer is 0.3% or less.

(3) The rolling bearing according to (1) or (2) above,
The drive shaft of the compressor that sucks, compresses, and discharges according to the rotation of the drive shaft fitted in the housing is rotatably supported.

  According to the bearing of the present invention, a nitride layer is provided on at least one of the raceway surface of the outer ring raceway and the inner ring raceway and the rolling surface of the rolling element, and the nitrogen concentration of the nitrided layer is 0.1% or more. Wear can be suppressed and a long life of the rolling bearing can be ensured regardless of the lubrication conditions. Further, since the surface nitrogen concentration is 0.3% or less, problems such as the occurrence of blowholes during the solidification process can be solved.

  Further, by using it as a bearing for the drive shaft of a compressor to which a large thrust force is applied, it is possible to provide a compressor with an extremely long life and high reliability.

DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments of the invention will be described in detail with reference to the drawings.
1 is a sectional view of a compressor for a car air conditioner using a thrust needle bearing according to a first embodiment of the present invention, FIG. 2 is an enlarged sectional view of the thrust needle bearing, and FIG. 3 is a perspective view of the thrust needle bearing shown in FIG. It is an expanded sectional view of the deep groove ball bearing which shows a modification.

  As shown in FIG. 1, a variable capacity compressor, which is a compressor for a car air conditioner, has a drive shaft 2 rotatably inserted into a housing 1, and a swash plate 3 can be inclined with respect to the drive shaft 2. The wobble plate 4 is slidably attached to the swash plate 3.

  A thrust bearing 5 is disposed between the swash plate 3 and the wobble plate 4. One end of a plurality of piston rods 6 is attached to the wobble plate 4 at equal intervals in the circumferential direction, and the other end of the piston rod 6 is connected to the piston 7. The piston 7 is provided so as to slide inside a cylinder 1a provided in the housing 1, and compresses and discharges the refrigerant gas flowing into the bore of the cylinder 1a.

  The right end of the drive shaft 2 is connected to a pulley 8 via a clutch mechanism CM, and a thrust plate 9 is press-fitted to the pulley 8 side outer periphery of the drive shaft 2 so as to rotate integrally. A thrust needle bearing 10 is disposed between the thrust plate 9 and the housing 1.

  As shown in FIG. 2, the thrust needle bearing 10 has a flanged shaft washer (that is, inner ring) 11 that is attached to the thrust plate 9 and a housing washer (that is, outer ring) 12 that is attached to the housing 1. An inner ring raceway 11a and an outer ring raceway 12a are provided on side surfaces of the shaft washer 11 and the housing washer 12 that face each other. Between the inner ring raceway 11a and the outer ring raceway 12a, a plurality of rollers 13 which are rolling elements are arranged so as to be able to roll in the circumferential direction, and the plurality of rollers 13 are equally spaced in the circumferential direction by a cage 14. Is held in. Nitride layers having a nitrogen concentration of 0.1% or more and 0.3% or less are provided on the surfaces of the rolling surfaces of the rollers 13 and the raceways of the inner ring raceway 11a and the outer ring raceway 12a, respectively.

  In this compressor, after the inside of the circulation system is evacuated, the refrigerant gas and the lubricating oil are sealed.

  Next, the operation of the car air conditioner compressor in this embodiment will be described.

  As shown in FIG. 1, the car air conditioner compressor starts its operation when the clutch mechanism CM is turned on. In such a case, when the pulley 8 is driven by a belt (not shown), the drive shaft 2 is driven to rotate, whereby the swash plate 3 rotates. Then, the wobble plate 4 performs a so-called razor-like operation, reciprocates the piston 7 through the piston rod 6 in the axial direction, and compresses and discharges the refrigerant gas.

  A reaction force when compressing the refrigerant gas is transmitted to the drive shaft 2 as a thrust force, and the thrust needle bearing 10 supports the thrust force between the thrust plate 9 and the housing 1. In addition, the refrigerant | coolant blowby gas generated with the operation | movement of piston 7 circulates in the arrow direction shown in FIG. 1, and lubrication of each movable part is performed with the mist-like lubricating oil contained in refrigerant | coolant blowby gas.

  Here, since the thrust needle bearing 10 is disposed at a position away from the piston 7, the mist-like lubricating oil is difficult to reach, and the lubrication conditions are severe as compared with other movable parts. Furthermore, when the refrigerant gas and the lubricating oil are sealed, the atmosphere in the circulation system is exhausted, and since the oxygen concentration is low, surface oxidation is unlikely to occur, and therefore normal quenching and tempering is not possible. Rollers and bearing discs that are used only tend to have a bearing life early due to the progress of adhesive wear with repeated metal contact. However, in the thrust needle bearing 10 described above, nitrogen is introduced into the surfaces of the two washer disks 11 and 12 and the rollers 13, and in particular, the region R (indicated by double hatching in FIG. 2) in which the surface pressure increases, that is, both the orbits. The nitrogen concentration in the nitrided layer provided on the raceway surface of the inner ring raceway 11a, the raceway surface of the outer ring raceway 12a, and the rolling surface of the roller 13, which are contact surfaces of the disks 11, 12 and the roller 13, is 0.1% or more. And since it is 0.3% or less, it becomes possible to suppress adhesion wear and to extend a bearing life.

  According to the thrust needle bearing 10 according to the above-described embodiment, nitrogen is introduced into the surfaces of both the washer disks 11, 12 and the rollers 13, and in particular, the inner ring raceway 11a, the outer ring raceway 12a, and the rollers 13 which are contact surfaces with each other. Since the nitrogen concentration of the nitride layer provided on the rolling surface is 0.1% or more, early wear can be suppressed and a long life can be ensured regardless of the lubrication conditions. Further, since the nitrogen concentration is 0.3% or less, problems such as the occurrence of blowholes during the solidification process can be solved.

  And as mentioned above, it can be set as a very long life and highly reliable compressor by using as a bearing of the drive shaft 2 of the compressor to which especially big thrust force is added.

  In the above embodiment, nitride layers are provided on both the raceway surface of the inner ring raceway 11a, the raceway surface of the outer ring raceway 12a, and the rolling surface of the roller 13, and the nitrogen concentration of the nitride layer is 0.1% or more and 0.1. Although it is set to 3% or less, it is possible to obtain the effect of suppressing early wear in either case.

  With reference to FIG. 3, the deep groove ball bearing which is 2nd Embodiment which concerns on this invention is demonstrated.

  The deep groove ball bearing 110 shown in FIG. 3 can be used in the compressor for a car air conditioner shown in FIG. 1 and can be used as a thrust bearing incorporated on the left side of the drive shaft 2.

  In FIG. 3, the deep groove ball bearing 110 is rotatable between an inner ring 111 attached to the drive shaft 2, an outer ring 112 attached to the housing 1, and an inner ring raceway 111 a of the inner ring 111 and an outer ring raceway 112 a of the outer ring 112. It consists of a ball 113 which is a plurality of rolling elements arranged and a cage 114 which holds the ball 113 at equal intervals in the circumferential direction. The cage 114 is formed by bending and combining two steel plates, but the operation is the same even if formed of other resins.

  Also in the deep groove bearing 110 according to the present embodiment, nitrogen is introduced into the surfaces of the balls 113, the inner ring 111 and the outer ring 112, and in particular, a region R (in FIG. 2) which is a mutual contact surface that is considered to have a high surface pressure. Nitrided layer provided on the raceway surface of the inner ring raceway 111a, the raceway surface of the outer ring raceway 112a, and the rolling surface of the ball 113, which are contact surfaces of the inner and outer races 111, 112 and the ball 113. Since the nitrogen concentration of 0.1% or more and 0.3% or less is used, early wear can be suppressed without any blowhole defects during the solidification process.

  Of course, the present invention is not limited to the above-described embodiment, and can be changed or improved within the scope of the invention. That is, the compressor for a car air conditioner is an example, and the bearing of the present embodiment can be used for various compressors such as a compressor that compresses a refrigerant regardless of other industrial use and home use. In particular, in the case of a natural refrigerant compressor, since the oxygen partial pressure in the refrigerant is low, a more remarkable effect can be obtained. Further, the type of rolling bearing used is not limited to the rolling bearing of the above embodiment.

  Various bearings with different surface nitrogen concentrations of rolling elements and races were subjected to wear tests under the following test conditions. Hereinafter, the wear test will be described.

(Test conditions)
(1) Test bearing size (inner diameter x outer diameter x height): 40 x 60 x 5 (mm)
(2) Axial load (thrust force): 1,500N
(3) Rotation speed: 3,000rpm
(4) Cage type: type shown in FIG. 2 in the above embodiment
(5) Test time: 500h
(6) Atmosphere: HCFC134a (including PAG)

Table 1 shows the results of a test of a thrust needle bearing including a rolling element and a raceway having different surface nitrogen concentrations according to the above test conditions.
The rolling elements and the washer are made of bearing steel (SUJ2), followed by carbonitriding, quenching (at 820 to 830 ° C. for 0.5 to 1 hour) and tempering (at 1 to 160 to 200 ° C.). 2 hours), and the surface nitrogen concentration was varied by changing the known carbonitriding conditions.
The surface nitrogen concentration was measured by quantitative analysis using an electron beam microanalyzer on the sample cross section. For the wear amount evaluation, the assembly height h before and after the test (see FIG. 2) was measured, and the amount of change was evaluated.

  According to the test results shown in Table 1, by setting the nitrogen concentration of at least one of the raceway surfaces of both washer disks and the rolling surfaces of the rolling elements to 0.1% or more, the nitrogen concentration was reduced to 0%. It can be seen that the amount of wear is reduced to 1/10 to 1/15 compared to the case of less than 1%. Therefore, the effectiveness of the present invention was demonstrated.

It is sectional drawing of the compressor for car air conditioners using the thrust needle bearing which is one Embodiment which concerns on this invention. It is sectional drawing of the thrust needle bearing in FIG. It is an expanded sectional view of the deep groove ball bearing which shows the modification of the thrust needle bearing in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Housing 2 Drive shaft 10 Thrust needle bearing (rolling bearing)
11 shaft washer (inner ring)
11a Inner ring raceway 12 Housing washer (outer ring)
12a Outer ring raceway 13 Roller (rolling element)
110 Deep groove ball bearings (rolling bearings)
111 Inner ring 111a Inner ring raceway 112 Outer ring 112a Outer ring raceway 113 Ball (rolling element)

Claims (3)

A rolling device comprising: an outer ring provided with an outer ring raceway; an inner ring provided with an inner ring raceway; and a plurality of rolling elements arranged so as to roll freely in the circumferential direction between the outer ring raceway and the inner ring raceway. A bearing,
At least one of the raceway surfaces of the outer ring raceway and the inner ring raceway and the rolling surface of the rolling element has a nitride layer,
A rolling bearing, wherein the nitride layer has a nitrogen concentration of 0.1% or more.   The rolling bearing according to claim 1, wherein the nitride layer has a nitrogen concentration of 0.3% or less.   The rolling bearing according to claim 1 or 2, wherein the drive shaft of a compressor that sucks, compresses, and discharges is rotatably supported in accordance with rotation of a drive shaft that is inserted into the housing.

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