JPH1082378A - Compressor for refrigerator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a compressor for a refrigerator without shortening longevity of a thrust bearing of a crankshaft even by using a combination of a substitute refrigerant not containing chlorine and esther oil with compatibility to it. SOLUTION: A carbon fluoride hydrogen refrigerant is used as a refrigerant, an electric motor and a scroll compression mechanism driven by this electric motor are arranged in the inside of a sealed container 1, a sub-bearing 12 is made a rolling type radial bearing, width of an inserting sliding part 6b of a crankshaft 5 to a sub-bearing inner ring 12b is made shorter than width of the inner ring 12b, and support of a thrust load of a crankshaft 6 is carried out on an end surface 12 of the inner ring 12b of the rolling type sub-bearing 12.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a compressor for a refrigerating machine, and more particularly, to a mixed refrigerant obtained by mixing at least one or more of a group of fluorocarbon-based refrigerants, that is, an alternative refrigerant. The present invention relates to a compressor for a refrigerator suitable for using an ester oil compatible with the refrigerant as the refrigerator oil.

[0002]

2. Description of the Related Art In a conventional compressor for a refrigerator, as shown in FIG. 3, a compression mechanism 2 for sucking and compressing a refrigerant is provided at one end inside a closed vessel 1 constituting a horizontal type pressure vessel. . The stator 4 of the electric motor 3 for driving the compression mechanism 2 is located at the center of the closed container 1 and is fixed to the inner surface of the side peripheral wall of the closed container 1. Is connected to a crankshaft 6 which is a drive shaft of the compression mechanism 2, and is arranged such that a rotation axis thereof is substantially horizontal.

The crankshaft 6 is supported by a main bearing member 10 having a main shaft 8 at one end on the compression mechanism 2 side fixed to the compression mechanism 2 by screwing, and the other end opposite to the main shaft 8. The portion is located on the other end side of the closed casing 1 and is supported by a sub-bearing member 11 fixed to the inner surface of the side peripheral wall of the closed casing 1. The portion of the main bearing member 10 that supports the main shaft 8 is a slide bearing 9, and the portion of the sub bearing member 11 that supports the other end of the crankshaft 6 is a radial rolling bearing 12 as shown in FIG. 2. The sliding bearing 9 and the rolling bearing 12 support the force generated on the crankshaft 6 when the compression mechanism 2 compresses the refrigerant by the rotational movement of the crankshaft 6. The thrust force applied to the crankshaft 6 is received by a thrust washer 13a.

On the other hand, a specific Freon R12 has been used as a refrigerant. Specified CFCs are scientifically stable, nonflammable, non-toxic, and widely used as ideal refrigerants, and have been used for many years, compared to the previous refrigerants, sulfur dioxide and methyl chloride.

In recent years, however, it has been confirmed that specific freon contains a chlorine atom in the molecule, which causes destruction of the ozone layer, and development and use of freon substitutes have been attempted. As a highly practical alternative refrigerant, a refrigerant such as HFC containing no chlorine is mentioned. In addition, the refrigerating machine oil needs to be compatible with the refrigerant from the viewpoint of lubrication and heat exchanger efficiency from the viewpoint of lubrication and heat exchanger efficiency. Mineral oil and alkylbenzene have been used for the specific chlorofluorocarbon. However, since this is extremely poor in compatibility with the above-mentioned fluorocarbon alternative, it is conceivable to use an ester oil compatible with the alternative refrigerant.

[0006]

However, when the alternative refrigerant is used, the alternative refrigerant does not contain chlorine, so that the lubricating property of the conventional specific CFC cannot be expected. For this reason, the sliding condition becomes severe, and the sliding speed is large in the simple thrust receiving structure with the thrust receiving portion of the conventional crankshaft as described above.
Both the thrust washer and the thrust receiving portion of the crankshaft are easily worn, and the life of the thrust receiving structure of the drive shaft is shortened. This is because the sliding state between the thrust receiving surface and the drive shaft is likely to be in a boundary lubrication state in which a part of the oil film has been cut because lubrication by the substitute refrigerant cannot be expected. It is considered that wear is caused.

In order to solve such a problem, there is a method of directly receiving the thrust bearing on the inner ring of the rolling bearing 12 as shown in FIG. However, since the crankshaft is inserted into the inner ring of the rolling bearing with a clearance, line contact occurs, and the inner ring rotates while sliding with the crankshaft.
For this reason, there has been a problem that the inner side of the inner ring of the rolling bearing and the thrust receiving portion are worn.

[0008] Such a reduction in the life of the thrust receiving structure portion of the drive shaft is attributed to the fact that the life of the thrust receiving structure portion is immediately reduced by the entire compressor in the case of a maintenance-free and long-life operation like a hermetic compressor. This is particularly problematic because it will last for a long time, and is not practical.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems, and to provide a compressor for a refrigerator which does not have a problem of a shortened life due to a thrust receiving structure of a drive shaft even when an alternative refrigerant containing no chlorine is used. It is intended to do so.

[0010]

SUMMARY OF THE INVENTION In order to achieve the above object, a compressor for a refrigerator according to the present invention is obtained by mixing at least one kind or two or more kinds of a group of hydrogen fluoride-based refrigerants as a refrigerant. Using a mixed refrigerant, an electric motor and a scroll compression mechanism driven by the electric motor are arranged inside the closed container, and a sub-bearing that supports an end of the compression mechanism opposite to the main shaft of the crankshaft is a rolling type. Radial bearing, the width of the sliding portion of the crankshaft inserted into the sub-bearing inner ring is shorter than the width of the inner ring, and the thrust load of the crankshaft is supported on the end face of the inner ring of the rolling-type sub-bearing. In addition, the inner ring of the rolling bearing receives the thrust force of the crankshaft, and the inner ring and the crankshaft rotate together without causing slippage, so that a highly reliable compressor with less wear can be provided.

[0011]

DETAILED DESCRIPTION OF THE INVENTION In order to solve the above-mentioned problems, the invention of claim 1 uses a hydrogen fluoride-based refrigerant as a refrigerant, and has an electric motor and a scroll compressor driven by the electric motor inside a closed container. A sub-bearing that supports the end of the compression mechanism opposite to the main shaft of the crankshaft is a rolling radial bearing, and the width of the sliding portion inserted into the sub-bearing inner ring of the crankshaft is set to the width of the inner ring. It is shorter than the width, and the thrust load of the crankshaft is supported on the end face of the inner ring of the rolling type sub-bearing, and the thrust force of the crankshaft is received by the inner ring end face of the rolling bearing, and the radial load side contact length is Because it is short, the inner ring adheres along the thrust surface. Therefore, even with a refrigerant without chlorine, the inner ring and the crankshaft rotate together without causing slippage, so that a highly reliable compressor with little wear can be provided.

According to a second aspect of the present invention, the center line of the width of the sliding portion inserted into the sub-bearing inner ring of the crankshaft substantially coincides with the center line of the rolling element of the sub-bearing. Since the thrust surface is in close contact with the inner ring and the inner ring and the crankshaft rotate together without causing slippage, it is possible to provide a highly reliable compressor with less wear.

According to a third aspect of the present invention, the outer diameter of the bearing flat portion of the thrust load of the crankshaft is equal to or larger than the outer diameter of the end face of the inner ring of the auxiliary bearing. Thus, the inner ring and the crankshaft rotate together without causing slippage, so that a highly reliable compressor with less wear can be provided.

According to the third aspect of the present invention, it is possible to provide a compressor with less wear and high reliability even when an ester oil compatible with a hydrogencarbon fluoride-based refrigerant is used as the refrigerating machine oil.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a compressor for a refrigerator as one embodiment of the present invention will be described with reference to the drawings.

The compressor for a refrigerator according to the present embodiment is a hermetic compressor. As shown in FIG. 1, the compressor is provided at one end inside a hermetic container 1 constituting a horizontal type pressure vessel. A compression mechanism 2 for sucking and compressing the refrigerant is provided. The stator 4 of the electric motor 3 for driving the compression mechanism 2 is
And a rotor 5 corresponding to the stator 4 of the electric motor 3 is coupled to a crankshaft 6 which is a drive shaft of the compression mechanism 2.
It is arranged such that its rotation axis is substantially horizontal.

The crankshaft 6 is supported by a main bearing member 10 fixed to the compression mechanism 2 by screwing a main shaft 8 at one end of the compression mechanism 2 side, and the other end opposite to the main shaft 8. The portion is located on the other end side of the closed casing 1 and is supported by a sub-bearing member 11 fixed to the inner surface of the side peripheral wall of the closed casing 1. The portion of the main bearing member 10 that supports the main shaft 8 is a slide bearing 9, and the portion of the sub bearing member 11 that supports the other end of the crankshaft 6 is a radial rolling bearing 12 as shown in FIG. 2. The rolling element of the rolling bearing 12 is a ball, but a roller or another element may be used as necessary.

The sliding bearing 9 and the rolling bearing 12
Supports the force generated on the crankshaft 6 when the compression mechanism 2 compresses the refrigerant by the rotational movement of the crankshaft 6.

The lower portion of the sealed container 1 on the end side from the partition member 11 is a lubricating oil reservoir 7, and the upper portion is a discharge chamber 18 for discharging the refrigerant gas to the outside of the closed container 1. An oil pump 14 driven by the other end of the crankshaft 6 is provided on the side facing 7 and screwed. In the oil pump 14, a suction port 14a opens in the lubricating oil reservoir 7, and a discharge port 14b communicates with a lubrication hole 6a formed so as to extend vertically from the other end of the crankshaft 6 to the sliding bearing 9 portion. ing. Therefore, the lubricating oil discharged by the oil pump 14 is first supplied to the sliding bearing 9 to lubricate it. Further, the portion of the sliding bearing 9 communicates with the inside of the closed casing 1 and the inside of the compression mechanism 2 through the gaps between the parts, and is also supplied to each sliding portion of the compression mechanism 2 to lubricate them.

The compression mechanism 2 includes a fixed scroll 2a and a movable scroll 2b.
c is supported at an eccentric position of the main shaft 8 via the slide bearing 9, and includes a fixed scroll 2a and a movable scroll 2b.
Are formed between the pockets 2d. When the movable scroll 2b is turned by the rotation of the crankshaft 6, the pocket 2d receives the refrigerant gas from the suction pipe 15 of the compressor when the pocket 2d communicates with the suction port 20 provided on the outer periphery of the fixed scroll 2a. It moves to the side of the discharge port 16 provided at the center of 2a. Due to this movement, the pocket 2d gradually reduces the volume and compresses the received refrigerant gas, and discharges the pocket gas when the pocket 2d communicates with the discharge port 16. The discharged refrigerant gas is discharged from the discharge port 16 into the closed container 1 and is passed through the motor side passage 17.
, And is discharged to the outside of the compressor through a discharge pipe 19 provided in the discharge chamber 18.

Thus, when the compression mechanism 2 is operated by the rotational movement of the crankshaft 6, the refrigerant gas is sucked and compressed repeatedly to execute a refrigeration cycle.

As the refrigerant gas, a mixed refrigerant obtained by mixing at least one kind or two or more kinds of a group consisting of carbon fluoride and hydrogen is used. Since it does not contain chlorine, it does not destroy the environment. Specific examples of such a refrigerant include a specific Freon HCFC22
HFCs and FCs with boiling points close to are considered.

On the other hand, the lubricating oil is an ester oil which is compatible with the refrigerant gas, and the lubricating oil supplied to the compression mechanism 2 and the lubrication which has flowed out of the sliding bearing 9 into the closed casing 1 are generated by the compression mechanism 2 The refrigerant gas is brought into contact with the refrigerant gas that is sucked into the compressor and discharged into the closed container 1 through the same passage, solubilized and mixed with the refrigerant gas to accompany it. Specific examples of such lubricating oils include fatty acid esters and carbonate esters.

By the entrainment of the lubricating oil to the refrigerant gas,
The refrigerant gas flowing to the discharge chamber 18 via the motor side passage 17 contains lubricating oil, and the lubricating oil is carried by its own flow and supplied to the rolling bearing 12 to some extent. In the discharge chamber 18, the refrigerant gas flowing into the discharge pipe 19 is separated into gas and liquid in the closed vessel 1, and the lubricating oil contained in the refrigerant gas is appropriately separated and collected in the lower lubricating oil reservoir 7. .

The auxiliary bearing 12 is provided on the partition member 11 and the outer ring 12 thereof.
a is press-fitted. Therefore, the outer ring and the 12a partition member 11 do not move relative to each other. A crankshaft having a diameter slightly smaller than the inner diameter of the inner ring is inserted into the inner ring 12b of the auxiliary bearing 12. This width is set smaller than the width of the inner ring 12b. The center line of the sliding portion 6b of the crankshaft 6 substantially coincides with the center of the rolling element (ball) 12c of the auxiliary bearing. The diameter of the press-fit portion of the crankshaft 6 into the rotor 5 is set to be larger than the portion 6b inserted into the inner race 12b, and the step is polished to form a thrust receiving portion 6c. Further, the rotor 5 and the stator 4 of the electric motor 3 are slightly displaced in the axial direction, and are set so that a thrust force is applied in a direction opposite to the compression mechanism 2 during operation.

When the electric motor 3 is operated in such a configuration, a force is applied to the crankshaft 6 in a direction opposite to the compression mechanism, and the thrust receiving portion 6c comes into contact with the end face 12d of the auxiliary bearing 12 to receive a thrust load. Due to the compression of the compression mechanism, a rotational load in the radial direction is applied to the auxiliary bearing. The sliding portion 6b receiving the radial force is set relatively thin, and its center line is substantially coincident with the center of the rolling element (ball) 12c of the sub bearing, so that the inner ring 12b has a degree of freedom of inclination. Therefore, the inner ring is moved by the thrust force to the thrust receiving portion 6c of the crankshaft 6.
Following, the thrust surface is in close contact. The inner ring 12b moves with respect to the outer ring 12a by the thrust force, and the rolling element 12c receives the thrust force. Therefore, the thrust force of the crankshaft is received by the inner ring end face of the rolling bearing, and the thrust can be received in the rolling state, so that wear is small. Further, since the contact length on the radial load side is short, the inner ring comes into close contact with the thrust surface. Therefore, even if the refrigerant does not contain chlorine, the inner ring and the crankshaft rotate together without causing slippage, so that a highly reliable compressor with less wear can be provided.

Further, the outer diameter of the thrust load bearing flat portion 6c of the crankshaft 6 is adjusted to the end surface 12 of the inner race 12b of the auxiliary bearing 12.
When the outer diameter is equal to or larger than the outer diameter of d, the slip generated on the radial side is suppressed by the frictional force on the thrust side. High compressor can be provided.

[0028]

As is clear from the description of the above embodiment,
According to the first aspect of the present invention, in a scroll compressor using a fluorocarbon-based refrigerant as the refrigerant, the auxiliary bearing is a rolling radial bearing, and the width of the sliding portion inserted into the auxiliary bearing inner ring of the crankshaft. Is smaller than the width of the inner ring, and the thrust load of the crankshaft is supported on the end face of the inner ring of the rolling-type auxiliary bearing, so that the thrust force of the crankshaft is received by the inner ring end face of the rolling bearing, and the radial load side contact length Because the inner ring adheres along the thrust surface because of its short length, even with refrigerant without chlorine, the inner ring and the crankshaft run around without causing slippage, providing a highly reliable compressor with less wear. it can.

According to the second aspect of the present invention, the center line of the width of the sliding portion inserted into the auxiliary bearing inner ring of the crankshaft substantially coincides with the center line of the rolling element of the width bearing. Since there is no inclination of the inner ring, the thrust surface is in close contact, and the inner ring and the crankshaft rotate together without causing slippage, so that a highly reliable compressor with little wear can be provided.

According to the third aspect of the present invention, the outer diameter of the bearing flat portion of the thrust load of the crankshaft is equal to or larger than the outer diameter of the end face of the inner ring of the auxiliary bearing, and the slip generated on the radial side is reduced on the thrust side. The compressor is suppressed by frictional force, and the inner ring and the crankshaft rotate together without causing slippage, so that a highly reliable compressor with little wear can be provided.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a compressor for a refrigerator as an embodiment of the present invention.

FIG. 2 is a cross-sectional view of a crank bearing surface and a rolling bearing portion showing an embodiment of the present invention.

FIG. 3 is a cross-sectional view of a conventional compressor for a refrigerator.

FIG. 4 is a sectional view of a conventional compressor for a refrigerator.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Closed container 2 Compression mechanism 2a Fixed spiral blade member 2b Revolving spiral blade member 3 Electric motor 6 Crankshaft 6b Sliding portion of crankshaft 6c Thrust receiving portion 9 Main bearing 12 Secondary bearing 12b Secondary bearing inner ring 12c Secondary bearing rolling element 12d Secondary bearing End face

Claims (4)

[Claims] The present invention uses a mixed refrigerant obtained by mixing at least one or more of a group of hydrogen fluoride-based refrigerants as a refrigerant, and arranges an electric motor and a compression mechanism driven by the electric motor inside a closed container. A main bearing member comprising: a fixed spiral blade member; a swirling spiral blade member; a crankshaft that drives the swirling spiral blade member to swing; and a main bearing that supports a main shaft formed on the crankshaft. And the auxiliary bearing that supports the end of the crankshaft opposite to the main shaft is a rolling radial bearing, and the width of the sliding part inserted into the auxiliary bearing inner ring of the crankshaft is the width of the inner ring. A compressor for a refrigerator having a width shorter than a width and supporting a thrust load of a crankshaft on an end surface of an inner ring of the rolling-type auxiliary bearing. 2. The refrigerator compressor according to claim 1, wherein the center line of the width of the sliding portion inserted into the auxiliary bearing inner ring of the crankshaft substantially coincides with the center line of the rolling element of the auxiliary bearing. 3. The compressor for a refrigerator according to claim 1, wherein the outer diameter of the bearing flat portion of the thrust load of the crankshaft is equal to or larger than the outer diameter of the end face of the inner ring of the auxiliary bearing. 4. The compressor for a refrigerator according to claim 1, wherein an ester oil is used as the refrigerator oil.