JPS62200018A - Bearing of compressor for refrigerator - Google Patents

Abstract

PURPOSE:To aim at improvement in bearing performance, by sintering a porous bronze alloy, impregnating graphite in a back metal of a bearing, and exposing this porous bronze alloy and the graphite both sparsely on a contact surface with a shaft. CONSTITUTION:A porous bronze alloy 17 is separated on a surface of a bearing, and graphite 19 or a solid lubricant is impregnated as much as 4-6% there. Therefore, even if lubrication becomes poor temporarily and comes to a state of exhaustive lubrication or boundary lubrication, seizure or binding is hard to happen owing to this graphite and, what is more, abrasion resistance is also sharply improved.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a bearing for a compressor for a refrigerator which sucks and compresses a refrigerant and has an oil reservoir in a container.

Conventional technology In recent years, reciprocating compressors have become popular as compressors for refrigerators.

Many types of compressors are used, including rotary compressors and scroll compressors.

An example of the above-mentioned scroll compressor will be described below with reference to the drawings and FIGS. 2 and 3.

In the figure, a compressor section 2 is arranged and housed in a closed container 1 in an upper part and an electric motor part 3 in a lower part. The compression part 2 has a spiral wrap 4b standing upright on a flat plate part 4a, an orbiting scroll 4 that makes an orbiting motion, a spiral wrap 6b standing upright on a flat plate 6a, and a fixed scroll 6 fixed to a block 6. are formed together. The lower end of the crankshaft 7, which is integral with the rotating shaft of the electric motor 30, is immersed in an oil reservoir 8 formed at the bottom of the closed container 1. On the other hand, an oil hole 7a that opens at an eccentric position is provided. The orbiting scroll 4 has
A communication hole 9 is provided at a position where the suction pressure is always maintained, and an intermediate chamber 10 is provided in which high-pressure gas flows from the communication hole into the suction pressure section of the orbiting scroll 4 to obtain a pressure approximately intermediate between the discharge pressure and the suction pressure. ing. The upper end of the crankshaft 7 is fitted into a boss portion 4C projecting downward from the orbiting scroll 4. The boss portion 4c rotates within the intermediate pressure chamber 10 of the block 6 by the rotation axis of the crankshaft 7, so that the orbiting scroll 4 performs an orbiting motion. Due to the movement of the mutual contact points of the rotating wrap 4b and the fixed wrap 5b, the gas sucked in from the suction pipe 11 is compressed inward from the spiral side chamber and discharged from the discharge hole 12 provided in the center of the fixed scroll 5 into the closed container. 1. The discharged refrigerant gas passes through the passage 13 provided on the outer circumference of the fixed scroll and the block outer passage 6a, and a part of the gas passes through the outer circumference passages 3a and 3b of the electric motor 3.
, and a part of it passes between the block 6 and the electric motor 3 and is sent out of the machine via the discharge pipe 13. The volume inside the closed container formed by both the lap portions 4b, 6b of the orbiting scroll 4 and the fixed scroll 5 and the flat plates 4a, 5a decreases and the pressure increases as the container moves from the outside to the center. As described above, the intermediate pressure chamber 1o formed by the orbiting scroll 4 and the block 6 is maintained at a pressure between the suction pressure and the discharge pressure by the communication hole 9. Therefore, the orbiting scroll 4 is pressed against the fixed scroll 5 by the differential pressure between this intermediate pressure and the pressure inside the compression section, and the seal portions in the gaps between the tips of the wrap portions 4b and esb and the flat plate portions 4a and 5a are maintained in close contact. do. Furthermore, the inside of the sealed container 1 has a discharge pressure,
Since it is higher than the intermediate chamber 1Q, the pressure difference causes the refrigerating machine oil to be pushed up the oil hole 7a in the crankshaft and supplied to the sliding parts. On the other hand, in this scroll compressor, fluid pressure within a closed space formed by both scrolls acts in the radial direction of the crank portion of the crankshaft 7 through the orbiting scroll 4. Therefore, the crankshaft 7 is supported in an inclined state between the main bearing 14 on the upper side of the block 6 and the lower bearing 15 on the lower side. However, the hermetic scroll compressor having the above structure has the following problems. The closed container is exposed to a high-temperature discharge gas atmosphere, and the scroll compressor and electric motor that constitute the discharge gas passage are exposed to high temperatures and maintained at approximately the same level as the discharge gas temperature.

Under such high temperatures, the bearing temperature decreases and the viscosity of the lubricating oil decreases, and a large amount of refrigerant is dissolved in the lubricating oil at discharge pressure, and as mentioned earlier, the pressure difference causes the lubricant to be supplied to each bearing. In this case, the pressure of the lubricating oil is reduced in the sliding parts, and the temperature of the lubricating oil rises due to the heat generated by sliding, causing the refrigerant to boil, making it difficult to form an oil film on the bearings, resulting in bearing wear and seizure. This causes problems with bearing reliability.

This is particularly noticeable in the bearing portion of the boss portion 4C of the orbiting scroll 4, and care must be taken.

Problems to be Solved by the Invention As a bearing for this type of compressor, Japanese Patent Application Laid-Open No. 69-194128
It has been proposed in the Publication No. That is, as shown in FIG. 3, an externally porous bronze alloy 17 is sintered on the back metal 16 forming the bearing of the boss portion 4C of the orbiting scroll 4, and a composite material made of a synthetic resin such as a plastic resin and a lubricant is formed. The bearing metal impregnated with No. 18 contains a soft and easy-to-remove composite material, which has good compatibility with the crankshaft 7, but has poor wear resistance during abnormal, normal operation, isothermal lubrication, and boundary lubrication. As a result, the bearing clearance becomes large, and the inclination and whirling of the crankshaft 7 become large. Furthermore, as described above, differential pressure oil supply has the drawback that if the bearing gap becomes large, the differential pressure cannot be ensured.

In view of the above drawbacks, the present invention aims to improve the reliability of bearings for refrigerator compressors.Means for Solving the ProblemsIn order to solve the above problems, the present invention This is a bearing for a compressor for a refrigerator, and has a structure in which a porous bronze alloy impregnated with 4 to 6 pieces of graphite is sintered to the back metal.

It has good wear resistance and prevents the bearing gap from increasing.

Embodiment Hereinafter, an embodiment of the present invention will be described with reference to FIG. 1, and components that are the same as those of the prior art will be denoted by the same reference numerals and detailed explanation thereof will be omitted.

The bearing is press-fitted into the block 6 and the boss portion 4C projecting below the orbiting scroll 4, and then ground into a circular shape to the required dimensions. Therefore, the surface of the bearing is as shown in Figure 1.
Porous alloy 17 is precipitated on the surface, and it is impregnated with 4 to 6 parts of graphite 9, a solid lubricant, so the bearing gap will not increase even under severe conditions of isothermal lubrication and boundary lubrication. . Therefore, since a differential pressure is ensured as in the scroll compressor described above, there is no rise in intermediate pressure, no increase in oil flow, and no increase in the inclination of the crankshaft 7, so the wraps 4b, s
The gap b is also maintained appropriately.

Effects of the Invention As described above, since the present invention is made of a sintered porous bronze alloy with a graphite-impregnated backing metal, lubrication is temporarily poor and a state of isothermal lubrication or boundary lubrication occurs. However, the above-mentioned substances do not cause seizing and hardening, and the wear resistance is also very good, and by providing the bearing of the present invention, highly reliable operation is possible. It is also a rolled bushing and is economically inexpensive.

[Brief explanation of drawings]

Fig. 1 is a sectional view of a bearing installed in a refrigeration compressor showing an embodiment of the present invention, Fig. 2 is a sectional view of a conventional refrigeration scroll compressor, and Fig. 3 is a sectional view of a conventional bearing. It is a diagram. 16... Back metal, 17... Porous bronze alloy, 19... Graphite. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Figure/q-Graphite Section 2 Figure 3

Claims (1)

[Claims] A bearing for a compressor for a refrigerator, which is made by sintering a porous bronze alloy in which the back metal of the bearing is impregnated with graphite, and sparsely exposing both the porous bronze alloy and graphite on the contact surface with the shaft.