JP2002242940A - Thrust bearing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To increase load capacity of a thrust bearing which is interposed between members eccentrically rotating mutually to support thrust load. SOLUTION: In a group of two rollers 14, 24 that are arranged for linear motion and have cages 16, 26, rolling axial centers of the rollers 14, 24 are perpendicular to each other, the rollers 14, 24 are respectively disposed on each side of an intermediate ring 30, and two bearing rings 12, 22 sandwich the rollers 14, 24 from the sides thereof, so that the eccentric rotating motion of the bearing rings 12, 22 is allowed. For scroll compressor or the like, for example, the first bearing ring 12 is fixed to a revolving scroll member 10, and the second bearing ring 22 is fixed to a housing 20.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thrust bearing, and more particularly, to a thrust bearing for supporting a thrust load between two members, such as a revolving scroll member and a housing in a scroll compressor, which perform eccentric rotational movement between them. About bearings.

The present invention is not limited to scroll compressors,
It can be used for various applications as a thrust bearing that supports a thrust load by being interposed between two members that perform eccentric rotational motion between each other.

[0003]

2. Description of the Related Art Japanese Unexamined Patent Publication No. 9-324816 discloses a thrust ball bearing for a scroll compressor. 7 and 8, the orbiting scroll member 1 and the spiral partitions 1b and 2b of the housing 2 are combined to form a compression chamber P between the spiral partitions 1b and 2b.
The fluid in the compression chamber P is compressed by sequentially changing the volume of the compression chamber P in accordance with the eccentric rotation of the orbiting scroll member 1 with respect to the housing 2.

[0004] The axis of the orbiting scroll member 1 and the axis of the drive motor 5 are eccentric (the amount of eccentricity is indicated by the symbol e).
When the output shaft 5a of the drive motor 5 rotates, the orbiting scroll member 1 rotates eccentrically with a turning radius equal to the amount of eccentricity e.
At this time, a force is applied to the orbiting scroll member 1 to rotate the orbiting scroll member 1, and a thrust load accompanying the fluid compression operation is applied. Therefore, a thrust ball bearing 4 is interposed between the orbiting scroll member 1 and the housing 2 (in the configuration shown in FIG. 8, the stationary frame 3 fixed to the housing 2).

As shown in FIG. 9, a thrust ball bearing 4 is
It is composed of a pair of races 4a, 4b and a plurality of balls 4c interposed between the raceways 4a1, 4b1 of the races 4a, 4b. The orbital rings 4a and 4b are fixed to mounting portions 1a and 3a of the orbiting scroll member 1 and the stationary frame 3 that are opposed to each other in the axial direction.

As shown in FIG. 10, the races 4a and 4b are rings having the same shape and dimensions, and a plurality of races 4a1 and 4b1 are formed on one end surface on the same circumference. Each of the raceway surfaces 4a1 and 4b1 is annular, and has a circular cross section. Ball 4c arranged on each raceway surface 4a1, 4b1
Rolls on the pitch circle of the raceway surfaces 4a1, 4b1 with the eccentric rotation of the orbiting scroll member 1. Raceway surface 4a1,
The pitch circle diameter PCD of 4b1 is equal to the eccentricity e.

[0007] In the scroll compressor, refrigerant and PA
Lubrication is performed by a fluid in which a refrigerating machine oil such as G oil (polyalkylene glycol) is mixed.

[0008]

In a ball bearing using a ball as a rolling element, a large load capacity cannot be obtained because of point contact. There's a problem.

An object of the present invention is to support a thrust load by interposing between two members which perform eccentric rotational movement between each other.
An object of the present invention is to provide a thrust bearing having a high load capacity.

[0010]

According to the first aspect of the present invention, there is provided a thrust bearing having a thrust load interposed between a first member and a second member which perform eccentric rotational movement between them. A first bearing ring 12 fixed to the first member 10, a second bearing ring 22 fixed to the second member 20, the first bearing ring 12 and the second bearing ring Intermediate ring 30 arranged between the bearing ring 22 and the first bearing ring 1
Plural first rollers 14 arranged between the second wheel and the intermediate wheel 30
A first cage 16 for holding the first rollers 14 so that the rolling axes are parallel to each other; and a plurality of second cages arranged between the second race 22 and the intermediate wheel 30. A roller 24 and a second retainer 26 for holding the second roller 24 so that the rolling axes are parallel to each other, and the rolling axis of the first roller 14 and the second roller 24 are provided. And the rolling axis of
The retainers 16 and 26 are formed of an injection-moldable synthetic resin, and a reinforcing material made of inorganic or organic fibers and a solid lubricant are added to the synthetic resin forming the retainers.

[0011] By adopting rollers as rolling elements,
Because of the line contact, the load capacity can be significantly increased as compared with a ball bearing using a ball. However, since the rolling of the roller is directed in one direction, a configuration for allowing an eccentric rotational movement different from the case where the ball is used as the rolling element is required. In the present invention, the first roller 14 and the second roller 24 are arranged on both sides of the intermediate wheel 30, and the rolling axis of the first roller 14 and the rolling axis of the second roller 24 are orthogonal to each other. Thereby, the eccentric rotation between the first member 10 and the second member 20 is allowed. Further, with the adoption of the rollers as the rolling elements, the rolling axis of the rollers is maintained in a predetermined direction by the retainer.

By making the material of the cages 16 and 26 a synthetic resin, the weights of the cages 16 and 26 can be reduced, and the inertia force can be reduced. In addition, mass productivity is improved by selecting a synthetic resin that can be injection molded.
Any resin material that can be injection-molded may be a thermoplastic resin or a thermosetting resin. In particular,
Thermoplastic polyimide resin (PI), polyetherimide resin (PEI), polyphenylene sulfide resin (P
PS), polyetheretherketone (PEEK), polyetherketone (PEK), polyethersulfone resin (PES), polyamide resin (PA) and the like. In addition, examples of the thermosetting resin include an aromatic thermosetting resin, a phenol resin, and an epoxy resin. These synthetic resins can be used alone or
Resin mixtures can also be used.

The strength of the cages 16, 26 is improved by adding a reinforcing material made of inorganic or organic fibers to the synthetic resin forming the cages 16, 26. Examples of the reinforcing material include inorganic and organic fibers such as glass fiber (GF) and carbon fiber (CF).

The wear resistance of the cages 16, 26 is improved by adding a solid lubricant to the synthetic resin constituting the cages 16, 26. Solid lubricants include polytetrafluoroethylene (PTFE), molybdenum disulfide (MoS
2), graphite and the like.

According to a second aspect of the present invention, in the thrust bearing according to the first aspect, the synthetic resin forming the retainers 16 and 26 is a chemical resistant resin. By selecting a synthetic resin with excellent chemical resistance, it can be used in special environments. For example, in the case of a thrust bearing for a scroll compressor using CO2 as a refrigerant, CO2 and PAG
It will be lubricated with fluid mixed with oil,
Since the environment is very easy to absorb water, such as in 2 + PAG oil, it is necessary to pay attention to hydrolysis and provide chemical resistance that can be used under these conditions.

According to a fourth aspect of the present invention, in the thrust bearing according to any one of the first to third aspects, the cage 1 is provided.
6 and 26 are of a roller guide type. By providing the cages 16; 26 with a roller guide type, a clearance can be secured between the cages 16; 26 and the races 12; 22 and the intermediate wheel 30. Therefore, heat generation can be reduced by improving the penetrability of a lubricant such as CO2 + PAG oil.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below by taking as an example a case where the present invention is applied to a thrust bearing for a scroll compressor as described above with reference to FIG.

FIG. 1 shows a cross section of a thrust bearing provided between an orbiting scroll member 10 and a housing 20 of a scroll compressor. FIG. 2 is a view taken along the line II-II in FIG. 1, and FIG. 1 shows a cross section along the line A-F in FIG. The thrust bearing has two races 12; 22, two sets of rollers 14 and 24 with cages, an intermediate wheel 30, and four guide pins 11a and 11b; 21a and 21b (see FIG. 6). are doing.

The first and second races 12 and 22 are fixed to the surfaces of the orbiting scroll member 10 and the housing 20 which face each other in the axial direction. That is, the first race 12 is in contact with the end face of the orbiting scroll member 10, and the guide pins 11 a,
Positioning and rotation prevention are performed by 11b. Similarly, the second bearing ring 22 is in contact with the end face of the housing 20, and the guide pins 21 a, 2 implanted in the housing 20.
Positioning and rotation prevention are performed by 1b.

The first roller 14 is interposed between the first race 12 and the intermediate wheel 30, and the second race 22 and the intermediate wheel 30 are interposed.
And a second roller 24 is interposed between the first roller 24 and the second roller 24. First Roll 1
4 is held by the first holder 16 and the rolling axes are parallel to each other. The second rollers 24 are held by a second retainer 26, and the rolling axes are parallel to each other. The rolling axis of the first roller 14 and the rolling axis of the second roller 24 are orthogonal to each other.

The orbiting scroll member 10 is mounted on the housing 2
By rotating eccentrically with a turning radius equal to the eccentric amount e (see FIG. 8) with respect to 0, the volume of the compression chamber P formed between the two spiral partition walls 1b and 2b changes, and the fluid compressing operation is performed. Done. The thrust bearing serves to prevent rotation of the orbiting scroll member 10 when such a compression operation is performed and to support a thrust load.

The first race 12 and the second race 22 have the same shape and dimensions. That is, as shown in FIG.
These races 12 and 22 are formed into a ring shape from, for example, a steel plate material by press working or the like, and provided with four pin holes 12a to 12d; 22a to 22d at equal intervals in the circumferential direction. Each of the pin holes 12a to 12d; 22a to 22d has substantially the same diameter as the guide pins 11a and 11b;
2:22 in the axial direction. The races 12 and 22 have a surface hardness of about HRC 60 to 64 by heat treatment.

As shown in FIG. 4, the intermediate wheel 30 has a ring shape and is provided with four pin holes 30a to 30d at equal intervals in the circumferential direction. Each of the pin holes 30a to 30d penetrates the intermediate wheel 30 in the axial direction, and is in the form of an elongated hole extending in the radial direction of the intermediate wheel 30. The intermediate wheel 30 is subjected to HR by heat treatment.
It has a surface hardness of about C60 to C64.

The first cage 16 and the second cage 26 have the same shape and dimensions. That is, these cages 1
Reference numerals 6 and 26 are ring-shaped as shown in FIG. Each retainer 16; 26 has a number of circumferentially arranged pockets 18; In the case of the illustrated embodiment, the number of pockets is 28. Pockets 18; 28 rollers 14;
24, which penetrate the retainers 16; 26 in the axial direction and are parallel to each other. Therefore, the rolling axes of the rollers 14 or 24 held by the cages 16 or 26 are parallel. Each of the retainers 16 and 26 has a pair of pin holes 16a and 16b at diametrically opposed positions.
26a and 26b. Each pin hole 16a, 16b; 26
a and 26b penetrate the retainer 16; 26 in the axial direction, and are in the form of elongated holes extending in the radial direction of the retainer 16;

The retainers 16; 26 are of a roller guide type, and a clearance is formed between the retainers 16; 26 and the first and second races and the intermediate wheel 30. FIG.
(B) and as shown in FIG. 5 (C), pocket 18;
28 are provided with guide projections 17; Guide protrusion 1
7; 27 are formed in opposed pairs at two locations in the longitudinal direction of the pockets 18; 28 and on the wall surfaces of the pockets 18; 28, and the distance between the opposed guide projections 17; Slightly smaller than the outer diameter. Therefore, when incorporating the rollers 14; 24 into the pockets 18; 28, the rollers 14;
14; 24 is pocket 18; 28 where one end is assembled
It is held inside and does not fall out carelessly. FIG.
As understood from (C), the amount of protrusion of the rollers 14; 24 projecting from the surface of the cage 16;
6 and the amount of clearance formed between the raceway surface 12; 22 and the intermediate wheel 30.

The first and second cages 16; 26 and the pin holes 16a, 16b; 26a, 26b;
The length in the longitudinal direction of 0a to 30d is such that the distance that the first and second guide pins 11a and 11b; Is set so as to correspond to the eccentricity e. Thereby, the orbiting rotation between the orbiting scroll member 10 and the housing 20 is restricted. Also, pin holes 16a, 16b; 26a, 26b;
The width dimension of the first and second guide pins 11a, 11a
b; first and second guide pins 11a, 11b to such an extent that 21a, 21b can move smoothly in the longitudinal direction of the pin hole;
It is set slightly larger than the outer diameter of 21a, 21b.

As described above, the first retainer 16 and the second retainer 26 have the same shape and dimensions.
As can be seen from the first and second rollers 14; 2
Four rolling axes are used in combination in orthogonal directions. In FIG. 6, the rollers are not shown. One end of each of the first guide pins 11 a and 11 b is implanted in the orbiting scroll member 10, and the other ends of the first guide pins 11 a and 11 b are pin holes 12 a and 12 c of the first bearing ring 12 and pin holes 16 a and 16 a of the first retainer 16. 16b through the pin hole 30 of the intermediate wheel 30
a, 30c. Also, the second guide pin 2
1a and 21b have one end implanted in the housing 20, and the other end penetrates through the pin holes 22d and 22b of the second raceway ring 22 and the pin holes 26a and 26b of the second retainer 26 to form the intermediate wheel 30. It enters the pin holes 30d and 30b.

The retainers 16 and 26 need to be lightweight in order to reduce the external force because the inertial force due to the weight acts on the rollers 14 and 24 as an external force. Further, it is necessary to have excellent chemical resistance. For example, in the case of a thrust bearing for a scroll compressor using a CO2 refrigerant, lubrication is performed by a fluid in which the CO2 refrigerant and PAG oil are mixed.
It is necessary that problems such as hydrolysis do not occur even under the special environment of 2 refrigerant + PAG oil. Therefore, the weight can be reduced by forming the retainers 16 and 26 from resin. Further, if the retainers 16 and 26 are manufactured by injection molding, mass productivity is high and the cost is low. Therefore, cage 16; 2
As the material of No. 6, a thermoplastic resin or a thermosetting resin that can be injection-molded is adopted. Specifically, thermoplastic polyimide resin (PI), polyetherimide resin (PEI),
Examples include polyphenylene sulfide resin (PPS), polyether ether ketone (PEEK), polyether ketone (PEK), polyether sulfone resin (PES), and polyamide resin (PA). Further, as the thermosetting resin, aromatic thermosetting resin, phenol resin,
Epoxy resins and the like can be mentioned. These synthetic resins can be used alone or as a resin mixture. Examples are glass fiber (GF),
By adding an inorganic or organic fiber such as carbon fiber (CF) as a reinforcing material, wear resistance and strength are improved. Due to its structure, the cage 1
6; especially the pin holes 16a, 16b; 26a. 26
Since external force can be applied to b, it is desired to have a certain degree of wear resistance and strength.

Also, polytetrafluoroethylene (PTF)
E), abrasion resistance can be improved by adding a solid lubricant such as molybdenum disulfide (MoS2) or graphite. The retainers 16; 26 are inevitable to slide with the wall portions 14; 24 of the pockets 18;
It is desirable to have some wear resistance.

[0030]

According to the present invention, the weight of the cage is reduced by using a synthetic resin as the material of the retainer, and the inertia force can be reduced. In addition, by selecting a synthetic resin that can be injection-molded, mass productivity is improved and cost can be reduced.

Further, by adding inorganic fibers such as glass fiber to the synthetic resin forming the cage, the strength of the cage is improved, and by adding organic fibers such as PTFE, the wear resistance of the cage is improved. Is improved.

Further, by selecting a synthetic resin having excellent chemical resistance, it can be used in a special environment. For example, even when used in a CO2 refrigerant + PAG oil, it is possible to avoid problems such as hydrolysis and to improve the durability of the retainer, and thus the thrust bearing.

As described above, the structural and functional requirements for the cage are satisfied, and the cost is reduced. As a result, a high load capacity thrust bearing using rollers as rolling elements is provided. be able to.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a thrust bearing portion in a scroll compressor.

FIG. 2 is a view taken along the line II-II in FIG.

FIG. 3 is a plan view of the bearing ring in FIG. 1;

FIG. 4 is a plan view of an intermediate wheel in FIG.

FIG. 5A is a plan view of the cage in FIG. 1, and FIG.
FIG. 5C is a plan view of the pocket, and FIG. 5C is an enlarged sectional view taken along line CC of FIG. 5B.

FIG. 6 is an exploded perspective view of the thrust bearing shown in FIG.

FIG. 7 is a conceptual diagram illustrating the principle of a scroll compressor.

FIG. 8 is a schematic sectional view of a scroll compressor showing a conventional technique.

FIG. 9 is an enlarged view of a thrust ball bearing part of FIG. 8;

FIG. 10 is a plan view of the mounting section in FIG. 8;

[Explanation of symbols]

 10 Orbiting scroll member 12 First race 12a-12d First pin hole 14 First roller 16 First retainer 16a, 16b Pin hole 17 Guide projection 18 Pocket 20 Housing 22 Second race 22a-22d Pin hole 24 Second roller 26 Second cage 26a, 26b Pin hole 28 Guide protrusion 28 Pocket 30 Intermediate wheel 30a-30d Pin hole

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Haruo Kamiya 1-1-1, Showa-cho, Kariya-shi, Aichi Prefecture Inside Denso Co., Ltd. (72) Inventor Tetsuya Hayashi 1578 Higashikaizuka, Iwata-shi, Shizuoka Pref. ) Inventor Kayasu Nakano 1578 Higashikaizuka, Iwata-shi, Shizuoka Pref. Inside (72) Inventor Masaru Kitagawa 1578 Higashikaizuka, Iwata-shi, Shizuoka F-term in Nutnu (F) (reference) 3H029 AA02 AB03 BB31 CC17 3H039 AA01 AA12 BB05 BB07 CC02 CC08 CC15 CC23 3J101 AA13 AA27 AA32 AA53 AA63 AA81 BA35 BA50 CA34 DA14 EA34 EA36 EA37 EA54 EA55 FA08 FA15 GA29

Claims (4)

[Claims] 1. A thrust bearing for supporting a thrust load interposed between a first member and a second member which perform eccentric rotational movement between each other, comprising: a first member fixed to the first member. A bearing ring, a second bearing ring fixed to the second member, an intermediate wheel disposed between the first bearing ring and the second bearing ring, and between the first bearing ring and the intermediate wheel A plurality of first rollers, a first retainer for holding the first rollers such that the rolling axes are parallel to each other, and a first roller disposed between the second race and the intermediate wheel. A plurality of second rollers; and a second retainer for holding the second rollers so that their rolling axes are parallel to each other. The rolling rollers of the first rollers and the second rollers are provided. The cage is formed of an injection-moldable synthetic resin, and the synthetic resin forming the cage is made of an inorganic or organic fiber. Thrust bearing, characterized in that the reinforcing material and the addition of solid lubricant consisting of. 2. The thrust bearing according to claim 1, wherein the synthetic resin forming the cage is a chemical resistant resin. 3. The thrust bearing according to claim 2, wherein the thrust bearing is used in a CO2 refrigerant + PAG oil environment. 4. A thrust bearing according to claim 1, wherein said cage is of a roller guide type.