JP2000130454A - Bearing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a bearing device capable of preventing creeping though using a needle-shaped rolling bearing. SOLUTION: A plurality of ring-shaped seal mounting grooves 3 are provided in a housing internal diametric surface part 1a serving as a bearing mounting surface. An elastic ring 4 for sealing is mounted in these seal mounting grooves 3. An oil film 5 is generated by applying oil or grease to a part between the elastic rings 4, 4 of the housing internal diametric surface part 1a. An outer ring 6 of a needle-shaped rolling bearing 2 is mounted in the housing internal diametric surface part 1a in a clearance fitting condition.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bearing device in which a roller bearing such as a needle roller bearing is mounted on a housing.

[0002]

2. Description of the Related Art When a bearing is mounted on a housing having a coefficient of thermal expansion larger than that of a bearing outer ring, for example, an aluminum housing, the bearing interference decreases with an increase in temperature and the bearing creep decreases. In some cases, a problem such as generation of sound due to expansion of the radial gap may occur. For example, in a compressor of a car air conditioner, an aluminum housing is often used to reduce the weight, and it is strongly desired to prevent the above-mentioned trouble caused by the temperature rise.
As a conventional creep prevention technology, for example, a ring for thermal expansion correction is interposed between the bearing outer ring and the housing, or a plurality of O-rings are attached to the bearing outer ring, and oil or grease is applied between the O-rings. One that supports a bearing with an oil film has been proposed. Each said ring,
It is mounted in an annular groove formed in the bearing outer ring.

[0003] However, these conventional creep prevention technologies are basically applied to deep groove ball bearings or large-sized cylindrical roller bearings, and are applied to products having a sufficient outer ring thickness. ing. Such a design concept can be applied to needle roller bearings and the like, but in the case of needle roller bearings, since the cross-sectional height of the outer ring is low, a ring is formed by processing an annular groove in the bearing outer ring. That is actually difficult to apply. In the case of a cylindrical roller bearing having a small outer ring in section height, it is difficult to apply the same as in a needle roller bearing.

Therefore, in the case of a needle roller bearing or a cylindrical roller bearing having a small outer ring in section height, there has been no method for preventing creep besides increasing the interference. In this case, there are the following problems. There is a limit to the increase in the closing time. When the housing is made of aluminum, the interference may decrease or a gap may occur with an increase in temperature. Since the interference varies, the contraction amount of the outer ring changes, and the radial gap changes. Eliminating the outer ring interference causes secondary problems due to creep, and increasing the radial clearance causes noise and vibration. As described above, it is difficult to prevent creep with needle roller bearings and cylindrical roller bearings whose outer ring has a low cross-sectional height. The use of roller bearings is required.

An object of the present invention is to provide a bearing device capable of preventing creep even when a roller bearing having a low outer ring cross section is used. Another object of the present invention is to prevent a change in the radial gap.

[0006]

A bearing device according to the present invention comprises:
A plurality of annular seal mounting grooves are provided on the inner diameter surface of the housing serving as the mounting surface of the bearing, and elastic rings for sealing are mounted in these seal mounting grooves in a partially protruding state. And an oil film is formed on the portion, and a roller bearing is attached to the inner diameter surface of the housing. According to this configuration, the outer ring of the bearing is supported by the oil film and the elastic ring formed between the elastic rings, and the elastic ring also prevents creep between the outer ring and the housing. The elastic ring also serves to prevent oil or grease from escaping outside due to the pressure between the outer ring and the housing. Since the elastic ring is mounted in the seal mounting groove formed in the housing, the outer ring does not need to be grooved, and can be applied without trouble even to a roller bearing having a low sectional height of the outer ring.

In the present invention, a clearance fit may be formed between the inner diameter surface of the housing and the outer diameter surface of the bearing. As described above, the outer ring is supported by the housing by the oil film between the elastic rings and the elastic rings even when the clearance is fitted. In addition, since the mounting is performed without the interference from the beginning, the radial gap does not change.

In the present invention, the roller bearing may have a shell type outer ring. Shell type outer ring
Because it is a drawn product such as a steel plate, it has a smaller thickness than a machined product.However, even with such a thin outer ring, no groove processing is required, so it is supported by an elastic ring and an oil film. Structure is applicable. In the present invention, the roller bearing may be a needle roller bearing. Needle roller bearings have a thin outer ring thickness, especially when the outer ring is a shell-type needle roller bearing, the outer ring has a small thickness. And the supporting structure can be applied.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described with reference to FIGS. This bearing device has the following configuration in a bearing device in which a roller bearing 2 is mounted on an inner diameter surface portion 1a serving as a bearing mounting surface of a housing 1. A plurality of (two in the illustrated example) annular seal mounting grooves 3 are provided in the housing inner diameter surface portion 1a, and a sealing elastic ring 4 is mounted in these seal mounting grooves 3 in a partially protruding state. An oil film 5 is formed in a portion between the elastic rings 4 and 4 of the housing inner diameter surface portion 1a, and the roller bearing 2 is mounted on the housing inner diameter surface portion 1a. The roller bearing 2 is used in a state where the roller bearing 2 is fitted in a gap with the housing inner diameter surface portion 1 a and floated on the oil film 5. The roller bearing 2 is pressed into the elastic ring 4.

The roller bearing 2 is a needle roller bearing, and includes an outer ring 6, a cage 7, and a needle roller 8 held by the cage 7.
It is composed of The roller 8 is directly rolled on a shaft (not shown). The outer ring 6 has both flanges, and is of a shell type, that is, a type obtained by drawing a metal plate such as a steel plate. The outer ring 6 may be a machined product.

The elastic ring 4 is made of an O-ring or the like, and is made of a material having corrosion resistance such as fluorine rubber or silicon rubber. The oil film 5 is formed by, for example, applying oil or grease to the housing inner diameter surface portion 1a and mounting the bearing 2 when the bearing 2 is mounted on the housing 1. It is preferable that the oil of the oil film 5 has high viscosity and corrosion resistance. For example, a silicon-based oil, grease, rust preventive oil, or the like is used.

According to the bearing device having this configuration, the outer ring 6 of the bearing 2 is provided with the oil film 5 formed between the two elastic rings 4 and 4.
And the elastic ring 4
Thereby, creep between the outer race 6 and the housing 1 is also prevented. Further, since the outer ring 6 is attached to the housing 1 without any interference from the beginning, the radial gap does not change. Since the elastic ring 4 is mounted in the seal mounting groove 3 formed in the housing 1, the outer ring 6 does not need to be grooved, and is a needle roller bearing having a thin outer ring 6, such as a shell type bearing. However, it can be applied without any trouble.

The effect of the oil film 5 for preventing creep will be described. When a load is applied to the bearing 2, the outer ring 6
Eccentric in the direction of load with respect to. However, since the oil film 5 is sealed in a portion surrounded by the elastic rings 4 and 4 between the outer ring 6 and the housing 1, when the outer diameter surface of the outer ring 6 tries to approach the housing inner diameter surface portion 1a rapidly. The oil film 5 made of a viscous fluid in the form of a thin film cannot flow easily and generates a large pressure. A so-called squeeze film effect occurs.
The elastic rings 4, 4 prevent the oil film 5, which has been pressurized at this time, from leaking outside.

If the pressure due to the squeeze film effect can be hung with the bearing load, the outer ring 6 is supported by the oil film 5 in a floating state without contacting the housing inner diameter surface 1a. When the bearing 2 receives a rotational load, this state is continuous, and a continuous high-pressure oil film 5 is formed between the outer ring 6 and the inner diameter surface portion 1a of the housing. The pressure due to the squeeze film effect is large enough to be sufficiently hung under a large rotational load under normal use conditions.

The elastic rings 4 and 4 are provided with the oil film 5 as described above.
And also prevents the outer ring 6 floating by the oil film 5 from rotating due to rolling frictional force in the rotational direction received on the rolling surface. Therefore, the outer ring 6 does not roll with respect to the housing 1 while receiving the rotational load, and no creep occurs.

Next, a compressor to which the bearing device of the present invention is applied will be described. The bearing device of each configuration described in the above [Means for Solving the Problems] is a compressor (for example, a compressor for a car air conditioner).
The present invention can be effectively applied to a bearing device for supporting a main shaft in a housing, a bearing device interposed between a movable scroll and an eccentric shaft, and the like. 3 and 4 each show an example of a compressor to which the bearing device of the present invention is applied.

FIG. 3 shows an example of a variable displacement compressor. This compressor is composed of a piston 2 of a cylinder 21.
2 is reciprocated through the swash plate 24 by rotation of the main shaft 23 to obtain a gas compression action. The present invention is applied to a plurality of radial bearing devices 26 and 27 that support the main shaft 23 in the housing 25 of the compressor. Bearing device is applied. The main shaft 23 is supported by the housing 25 via a thrust bearing 28. The radial bearing devices 26 and 27 have the configuration described with reference to FIG. 1, and the housing 25 of the compressor is the housing 1 in the example of FIG. The rollers 8 are in rolling contact with the outer diameter surface of the main shaft 23. The swash plate 24 is connected to the main shaft 23, and performs a motion called a razor motion, that is, a motion of shifting the tilt direction in the circumferential direction at a constant tilt angle by rotation of the main shaft 23. The swash plate 24 is supported by the housing 25 via a thrust bearing 29. The housing 25 is made of aluminum. This compressor is a wobble type variable displacement compressor and is used for a car air conditioner.

The bearing devices 26 and 27 that support the main shaft 23 of the compressor have a large influence of heat generated by the gas compression operation, and the housing 25 is made of aluminum for weight reduction, so that creep is likely to occur. Under the environment. Moreover, for automobiles, reduction of noise and vibration is strictly required. Under such circumstances and requirements, by using the bearing device of the present invention, a sufficient creep preventing effect can be obtained. Further, by using the needle roller bearings, and particularly by using the needle roller bearings of the shell type outer ring, it is possible to reduce the weight, size, and cost of the bearings. Auto parts are required to be lighter in grams, and the use of needle roller bearings to improve the anti-creep effect effectively meets the requirements for compressors for car air conditioners. is there.

FIG. 4 shows an example of a scroll compressor. This compressor performs a scroll operation of the movable scroll 32 with respect to the fixed scroll 31,
A gas compression action is obtained. Movable scroll 32
Is rotatably supported by an eccentric shaft portion 33a of the main shaft 33 via a bearing device 34, and is scrolled by the rotation of the main shaft 33. The main shaft 33 is rotatably supported by a housing 36 of the compressor by bearings 35. Bearing device 3 between movable scroll 32 and eccentric shaft portion 33a
4, the bearing device of the present invention is used. This bearing device has the configuration described with reference to FIG. 1. In this case, the base 32a of the orbiting scroll 32 becomes the housing 1 in the bearing device of FIG. This compressor is also used for a car air conditioner of an automobile. Thus, also when applied to a scroll compressor, the effect of preventing creep by the bearing device of the present invention and the effect of reducing the weight and size by using the needle roller bearing 2 are effective.

Although the above embodiment has been described with reference to the case where the bearing 2 is a needle roller bearing, the bearing 2 may be a cylindrical roller bearing. The cylindrical roller bearing may have a shell-type outer ring or a machined product. Also in the compressor shown in FIGS. 3 and 4, cylindrical roller bearings may be used for the radial bearing devices 26 and 27 and the bearing device 34 of the eccentric shaft portion 33a.

[0021]

According to the present invention, a plurality of annular seal mounting grooves are provided on the inner diameter surface of the housing serving as the mounting surface of the bearing.
Since a sealing elastic ring is mounted in these seal mounting grooves in a partially protruding state, and an oil film is formed on a portion between the elastic rings on the inner diameter surface of the housing, a roller bearing having a low outer ring cross-sectional height is provided. , Creep can be prevented by an oil film. When the roller bearing is fitted into the housing inner diameter surface portion with a gap, the roller bearing is mounted without any interference from the beginning, so that the radial gap does not change.

[Brief description of the drawings]

FIG. 1 is a partial sectional view of a bearing device according to an embodiment of the present invention.

FIG. 2 is a partial sectional view of a roller bearing used in the bearing device.

FIG. 3 is a sectional view showing an example of a compressor to which the bearing device is applied.

FIG. 4 is a sectional view showing another example of a compressor to which the bearing device is applied.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Housing 1a ... Inner-diameter surface part 2 ... Roller bearing 3 ... Seal mounting groove 4 ... Elastic ring 5 ... Oil film

Claims (4)

[Claims] 1. A plurality of annular seal mounting grooves are provided in a housing inner diameter surface portion serving as a mounting surface of a bearing, and a sealing elastic ring is mounted in these seal mounting grooves in a partially protruding state. A bearing device in which an oil film is formed in a portion between the elastic rings, and a roller bearing is mounted on the inner diameter surface of the housing. 2. The bearing device according to claim 1, wherein a clearance fit is formed between the inner diameter surface of the housing and the outer diameter surface of the bearing. 3. The bearing device according to claim 1, wherein said roller bearing has a shell-type outer ring. 4. The bearing device according to claim 1, wherein the roller bearing is a needle roller bearing.