JPS5850325A - Bearing device - Google Patents

Abstract

PURPOSE:To reduce thermal deformation of a housing which is caused by thermal expansion due to a temperature rise and prevent a bearing from rotating and fusing by axially disposing a suitable number of fine grooves on a bearing fitting surface of the housing. CONSTITUTION:The inner surface 1a of a housing is provided with two small grooves 5a, 5b. The grooves 5a, 5b are adapted to reduce thermal deformation of a housing 1 caused by thermal expansion due to a temperature rise of a bearing 2. That is, the thermal expansion of the housing is absorbed by the grooves 5a, 5b.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a bearing device that press-fits a bearing into a housing.

A conventional bearing device will be explained with reference to FIGS. 1 and 2.

The bearing device includes a slide bearing 2 and a housing 1 that fixes and supports the slide bearing 2. The method of fixing the sliding bearing 2 to the housing side is based on a press-fitting method (tight fit). FIG. 1 shows a bearing device incorporating a main shaft 4. As shown in FIG. FIG. 2 shows a longitudinal section of FIG. As the main shaft 4 rotates, heat is generated due to sliding on the bearing surface, and the temperature of the bearing portion increases. The temperature of the bearing portion also changes depending on the temperature conditions around the bearing device. Generally, the temperature of the bearing section further increases due to the influence of external temperature. When the temperature of the bearing increases, Ujifugu 1 and bearing 2...
Thermal deformation occurs due to thermal expansion. Inner surface 1a of housing 1
Both the outer surface 1b and the outer surface 1b extend in the radial direction due to thermal expansion. Further, the bearing 2 also thermally expands in the radial direction. however,
Since the housing 1 has a larger diameter than the bearing 2, the fit between the two becomes loose due to thermal expansion. When the fit between the two becomes loose, the bearing 2 rotates together with the main shaft and slides on the inner surface of the housing (the outer surface of the bearing) Ia.

Since the inner surface 1a of the housing is not supplied with lubricating oil, when the inner surface 1a slides, the mechanical loss at the bearing section increases significantly, and eventually seizure occurs on the inner surface 1a.

Therefore, the bearing 2 no longer functions as a bearing.

Further, when the bearing device slides on the inner surface 1a of the housing, abrasion powder is generated at that portion, and this abrasion powder has an adverse effect on the bearing device and the entire machine that uses this device.

The present invention was invented in view of the above, and aims to alleviate the thermal deformation of the housing caused by thermal expansion due to the temperature rise of the bearing, thereby preventing rotation of the bearing and, by extension, preventing seizure of the bearing device. .

In order to achieve the above object, the present invention provides an appropriate number of narrow grooves in the axial direction on the bearing fitting surface of the housing, absorbs thermal expansion of the housing with the grooves, and maintains a tight fit between the housing and the bearing at all times. state r (characterized by

An embodiment of the present invention will be explained in detail with reference to FIGS. 3 to 8.

FIG. 3 shows a longitudinal cross-sectional view of the bearing device, and FIG. 4 shows a cross-sectional view, in which two small grooves (or recesses) ba and bb are provided on the inner surface of the housing 1a. The grooves 5a and 5b allow the thermal deformation of the housing caused by thermal expansion due to a rise in the temperature of the bearing portion to be moderated.In other words, the grooves 5a and 5b absorb the thermal expansion of the housing.

The state is shown in FIG. The cutout portion 5a can extend not only in the radial direction but also in the circumferential direction due to the thermal expansion of the housing, so it contracts as indicated by 5' (indicated by a broken line) and absorbs the thermal expansion of the housing. Therefore, the housing 1 and the bearing 2 can always be tightly fitted, and the bearing 2 will not move.

6 and 7 show an embodiment in which the present invention is applied to a boss bearing of an orbiting scroll of a scroll compressor. FIG. 7 is a view seen from direction A in FIG. 6. A case where a scroll compressor is used as an air compressor will be explained. In the case of an air compressor, the compression index is large and the operating pressure ratio is higher than in the case of a refrigerant compressor, so the discharge air temperature becomes very high. (In the case of air, the theoretical discharge temperature is about 250° C. at a pressure ratio of 8.) The air discharge port is the opening 21 in the center of the scroll. Therefore, the temperature of the bearing portion of the orbiting scroll boss portion provided at the center of the orbiting scroll increases to near the discharge temperature, and is greatly affected by thermal expansion.

Figure 6 shows a rolling bearing (outer ring 23, inner ring 24) as a bearing.
, a rolling element 25, etc.), and FIG. 7 is a view taken in the direction of arrow A. A groove 26 is provided on the inner surface 29a of the orbiting scroll boss portion 29 corresponding to the housing, so that thermal deformation of the boss portion can be absorbed by the notch portion 26. In the figure, 7 indicates the fixed scroll 8 is an orbiting scroll, and 12 indicates a rotating shaft.

FIG. 8 shows another embodiment of a bearing device using a soft metal plain bearing.1. Multiple grooves (3 in Figure 8) +5
2, +5b, +5C on the housing side 11,
The same cylindrical sliding bearing 12 is press-fitted, and the convex portion 12a formed by the deformation of the bearing side at the time of press-fitting can have the effect of preventing the bearing 12 from rotating. Convex part 1
Even if 2a=E is formed, the notches 15a, 15b,
Since the grooves 15c still have a space, the thermal deformation of the housing side 11 due to the temperature rise can be prevented from occurring in the grooves 15a, 1.
54- It can be absorbed by 15c.

As explained above, according to the present invention, the temperature of the bearing section is 1.
It is possible to alleviate the thermal deformation of the housing caused by the thermal expansion caused by the rise in temperature, and to prevent the rotation of the bearing and the generation of abrasion powder associated with it, which was seen in the conventional technology, and to provide a highly reliable bearing device. The reliability of all 4 machines is 1J
will be improved.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view of a conventional bearing device, FIG. 2 is a sectional view perpendicular to the axis of FIG. 1, and FIG. 3 is a longitudinal sectional view of a bearing device according to the present invention. 4 is a cross-sectional view taken in the direction orthogonal to the axis of FIG. 3, FIG. 5 is an explanatory view showing how the housing absorbs thermal expansion, and FIG. 6 is a longitudinal cross-sectional view showing an embodiment in which the present invention is applied to a scroll compressor. FIG. 7 is a cross-sectional view of a bearing device showing an embodiment of the embodiment shown in the direction of arrow A in FIG. 6 and in FIG. 8. 1.11...Housing 2.12...Bearing 5a
, 5b, +58. +5b, 15C... Hosomizo's agent Patent attorney Ii 1) Yuki Toshi - Z Iwao bω

Claims (1)

[Scope of Claims] 1. A bearing device in which a cylindrical bearing is press-fitted into a bearing housing, characterized in that an appropriate number of narrow grooves are provided in the axial direction on the bearing fitting surface of the housing. 2. The bearing is made of soft metal, and due to deformation during press fitting, -C
The bearing device according to claim 1, wherein the convex portion is formed in accordance with the housing groove.