JPS59194128A - Bearing of compressor for refrigerator - Google Patents

Abstract

PURPOSE:To improve the reliability of a bearing by working the surface of the bearing in such a manner that both a composite material and a porous bronze- group alloy are previously exposed on the surface of the bearing. CONSTITUTION:On the surface of a bearing, a porous alloy 16 is exposed, so that even if a crankshaft 4 slides, a surface layer is not stripped, and a bearing clearance is not enlarged. As the surface of the bearing is formed of a composite material 17 composed of the porous alloy 16, plastic resin having a self-lubricating property and a lubricating material, even if oil supply temporarily goes wrong and the boundary lubricating state occurs, hesitation of slide due to seizure will hardly take place. A refrigerant is mixed in lubricating oil in an oil sump of a general compressor for a refrigerator. When such lubricating oil is supplied, the mixed refrigerant is caused to boil by sliding heat in the bearing, so that the boundary lubricating state is easy to happen at the bearing portion. Therefore, the operation can be conducted with high reliability by providing the above bearing.

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to a bearing for a refrigeration compressor that sucks and compresses refrigerant and has an oil reservoir in a container [Prior Art] A compressor for a refrigeration machine There are various types of compressors, such as reciprocating compressors, rotary compressors, scroll compressors, etc., and a conventional scroll compressor for refrigeration will be explained with reference to FIG.

Inside the airtight container 1, a compressor section 2 is housed in an upper part and an electric motor part 3 is arranged in a lower part. The compressor part is a flat plate part 6
The orbiting scroll 6 having a thinly wound wrap 6b standing upright on a and the fixed scroll 7 fixed to the frame 5 having a thinly wound wrap 7b standing upright on the flat plate part 7a and the orbiting scroll 6 making an orbiting movement are formed together. Electric motor 3
The lower end of the crankshaft 4, which is integral with the rotating shaft, is immersed in an oil reservoir 9 formed at the bottom of the closed container 1.
An oil hole 4a is formed at the lower end of the rotor, which opens toward the shaft center, and at the upper end, an oil hole 4a opens at a position eccentric to the rotational shaft center. The orbiting scroll 6 is provided with a communication hole 10 at a position where the pressure is approximately intermediate between the suction pressure and the discharge pressure, and an intermediate pressure chamber 8 where the pressure is intermediate is provided. The upper end of the crankshaft 4 is fitted into a boss portion 6C projecting downward from the orbiting scroll 6. Due to the rotation of the crankshaft 4, the tip portion 6C rotates within the intermediate pressure chamber 8 of the frame 5, thereby performing the orbiting motion of the six orbiting scrolls, and by moving the mutual contact points of the orbiting wrap 6b and the fixed wrap 7b) The gas sucked in through the suction pipe 11 is compressed inward from the thinly wound outer chamber and is discharged into the sealed container 1 from the discharge lower c provided at the center of the fixed scroll 7. The passage 7d1 passes through the frame outer circumferential passage 5a, a part passes through the outer circumferential passage 3a, ab of the electric motor 3, and a part passes through the frame 5.
and the electric motor 3, and is sent out to the outside of the machine via the discharge pipe 12. The volume of the sealed chamber formed by both the lap parts 6b, 7b and the flat plate parts 6a, 7a of the orbiting scroll 6 and the identification scroll 7 decreases and the pressure increases as it moves from the outside to the center. Therefore, as described above, the intermediate pressure chamber 8 formed by the orbiting scroll 6 and the frame 5 has a communication hole 1.
o is maintained at a pressure intermediate between the suction pressure and the discharge pressure. Therefore, the orbiting scroll 6 is pressed against the fixed scroll 7 by the pressure difference between this intermediate pressure and the pressure inside the compression section.
The seal portions in the gaps between the tips of the wrap portions 6b, 7b and the flat plate portions 7a, 5a maintain close contact. Furthermore, the discharge pressure inside the sealed container 1 is higher than that in the intermediate pressure chamber 8, so due to the pressure difference, the refrigerating machine oil is pushed up the oil hole 4a in the crankshaft and supplied to the sliding parts. . On the other hand, in this scroll compressor, the fluid pressure in the closed space formed by both scrolls acts in the radial direction of the crank portion of the crankshaft 4 through the orbiting scroll 6. For this reason, the crankshaft 4
is supported in an inclined state between a main bearing 13 on the upper side of the frame 5 and a lower bearing 14 on the lower side. However, the hermetic scroll compressor having the above structure has the following problems. The closed container is in a high temperature discharge gas atmosphere,
The scroll compressor and electric motor that constitute the discharge gas passage are exposed to high temperatures and are maintained at approximately the same level as the discharge gas temperature. Under such high temperatures, the bearing temperature is not high, and the viscosity of the lubricating oil decreases, and a large amount of refrigerant melts in the lubricant at discharge pressure9, and as mentioned above, the pressure difference causes each bearing to If lubricating oil is supplied to the bearing, the pressure of the lubricating oil will be reduced within the sliding part, and the temperature of the lubricating oil will rise due to the heat generated by sliding, causing the melted refrigerant to boil, making it difficult for an oil film to form in the bearing. Bearing wear and, in some cases, seizure may occur, which poses problems in terms of bearing reliability.

-3= Metal sliding bearings made of alloy are generally used as bearings for this type of compressor, but they have the drawbacks mentioned above, and there are cases where rolling bearings are used instead of sliding bevel bearings. It has the drawback that it is more expensive than the previous model and cannot be made smaller and lighter.

Further, when a carbon bearing or the like is used as the bearing, if the crankshaft 4 is tilted as described above, one-sided contact occurs and the bearing wears out considerably.

There is also an example of using a bearing as shown in FIG. 2, a cross section of which is shown. This type of bearing has a back metal 15 sintered with a porous alloy 16, a plastic resin impregnated with a composite material 17 made of a lubricant, etc., and a surface layer made of the composite material 1.
7, it has good compatibility with the crankshaft 14, but it has the disadvantage that it comes off in the early stages of operation, making bearing antifreeze difficult, and increasing the tilt and swing of the crankshaft 14. Also as mentioned above. In the case of differential pressure oil supply, if the bearing clearance becomes large, the differential pressure cannot be ensured. Such rolled bearings are generally used without processing, and they are not used in machines such as refrigeration compressors where the bearing clearance must be kept below a certain value. As mentioned above, it has difficult drawbacks.

[Purpose of the invention]

The present invention has been made in view of the above-mentioned problems, and is aimed at improving the reliability of bearings of refrigeration compressors that supply lubricating oil to the bearings by providing an oil reservoir in a container. be.

[Summary of the invention]

As mentioned above, it is difficult to form an oil film on bearings for refrigeration compressors, and depending on operating conditions, boundary lubrication is likely to occur. Therefore, the bearing is made of a composite material consisting of a synthetic resin such as plastic resin and a lubricant, with a porous alloy sintered on the back metal, and the surface layer is made of a composite material. Even after operation, the bearing surface layer remains unchanged. In order to prevent the bearing from coming off and increasing the bearing gap, the surface of the bearing is processed in advance to expose both the composite material and the porous bronze alloy before use.

[Embodiments of the invention]

A sectional view of the bearing of the present invention is shown in FIG. 3 below.

The bearing of the present invention is manufactured by press-fitting the bearing into the boss portion 6C protruding below the frame 5 and the orbiting scroll 6 as shown in FIG. The surface layer S of the composite material 170 is processed and removed. Therefore, as shown in Fig. 3, the porous alloy 16 is exposed on the surface of the bearing, so even if the crankshaft 4 slides, the surface layer cannot be removed and the bearing gap becomes large. There isn't. Therefore, when oil is supplied using a differential pressure such as in the scroll compressor mentioned above, an appropriate differential pressure is ensured, so there is no increase in intermediate pressure or oil rise.
Furthermore, since the inclination of the crankshaft 4 does not increase, the lap 5a
, 7b clearance can also be maintained appropriately. As mentioned above, the surface of the bearing is made of a composite material 17 consisting of a porous alloy 16, a self-lubricating plastic resin, and a lubricant, so lubrication temporarily deteriorates and a state of boundary lubrication occurs. too,
Because of this composite material, seizing and hardening are less likely to occur. Note that the lubricating oil in the oil sump 9 of a general refrigeration compressor contains refrigerant, and when this lubricating oil is supplied,
In the bearing, the mixed refrigerant boils due to heat generated by sliding, and a boundary lubrication condition is likely to occur in the bearing portion. Therefore, by providing the bearing of the present invention, highly reliable operation is possible.

Furthermore, this bearing is made of a wound bushing and has the advantage of being economically inexpensive.

[Brief explanation of the drawing]

Fig. 1 is a sectional view of a scroll compressor for refrigeration, Fig. 2 is a sectional view of a conventionally used bearing, and Fig. 3 is a sectional view of a bearing provided for refrigeration compression according to the present invention. It is a diagram. 1... Airtight container 2... Compressor section 3... Electric motor 4... Crankshaft 5... Frame 6.
...Orbiting scroll 7...Fixed scroll 8
...Intermediate pressure chamber 9...Oil reservoir 10...Communication hole 11...Suction pipe 12...Discharge pipe 13
...Main bearing 14...Lower bearing 15...Backing metal 16...Alloy 1=7- 8- Fig. 2, Fig. 43 16 Shimizu Factory, Hitachi, Ltd., 390 Muramatsu, Shimizu City

Claims (1)

[Claims] In the bearing of a compressor for a refrigerator, a porous bronze alloy in which the back metal is impregnated with a composite material consisting of a synthetic resin and a lubricant is sintered, and the contact surface with the shaft is coated with the porous bronze alloy and the composite material. A bearing for a compressor for a refrigerator, characterized in that both sides are sparsely exposed.