JPH08326675A - Compressor for refrigerator - Google Patents

Abstract

PURPOSE: To suppress reduction of a life caused by a bearing even if a compressor is used by combining an alternative refrigerant without containing chlorine with ester oil having compatibility by forming the material of a rolling body and a race for composing a rolling bearing out of a material which contains tempering resistance component. CONSTITUTION: The compressing mechanism 2 of refrigerant is arranged on one end side in a closed container 1, the stator 4 for a motor 3 for driving the compressing mechanism 2 is arranged on the center part in the closed container 1, and also a crankshaft 6 formed as the driving shaft of the compressing mechanism 2 is connected to a rotor 5 corresponding to the stator 4. In the crankshaft 6, a main shaft 8 in the compressing mechanism 2 is supported on a main bearing member 10, and a part opposing to the main shaft 8 is supported on an auxiliary bearing member 11. A part for supporting the main shaft 8 of the main bearing member 10 is formed as a bearing 9, and a part for supporting the other end part of the crankshaft 6 of the auxiliary bearing member 11 is formed as a rolling bearing 12. In this case, the materials of a rolling body 31 and a races 32, 33 for composing a rolling bearing 12 are made of a material which contains tempering resistance component.

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 in particular, it uses as a refrigerant a mixed refrigerant in which at least one kind or a combination of two or more kinds of fluorocarbon-hydrogen based refrigerants, that is, an alternative refrigerant The present invention relates to a compressor for a refrigerator, which is suitable when an ester oil compatible with the refrigerant is used as the refrigerator oil.

[0002]

2. Description of the Related Art In a conventional compressor for refrigerating machine, a high-carbon chromium steel generally used as a bearing steel shown in JIS G4805, JIS G4401, is used as a material for a bearing ring and rolling elements of a rolling bearing that supports a drive shaft of a compression mechanism. The various types of steel such as the carbon tool steel shown in 1) and the chrome molybdenum steel shown in JIS G4105 are used after being appropriately quenched and tempered.

On the other hand, a specific CFC R12 or a designated CFC R22 was used as the refrigerant. Compared with the previous refrigerants such as sulfur dioxide and methyl chloride, Specified Freon is chemically stable, has no flammability and toxicity, is widely used as an ideal refrigerant, and has been used for many years.

Recently, however, it has been confirmed that a specific chlorofluorocarbon contains a chlorine atom in the molecule, which causes the destruction of the ozone layer, and an alternative chlorofluorocarbon has been developed and used.

As a highly practical alternative refrigerant, chlorine-free HFC (Hydro Fluoro Carbo) is used.
n) The refrigerant mentioned above is cited as "hydraulic pressure technology '9.
4.6. (Published by Nihon Kogyo Publishing).

Further, the refrigerating machine oil must be compatible with the refrigerant in terms of lubrication, which is carried and supplied to each part of the compressor by the flow of the refrigerant and from the viewpoint of heat exchanger efficiency. Mineral oil and alkylbenzene were used for the specified CFCs and designated CFCs, but since the compatibility with the alternative CFCs is extremely poor, it is considered to use compatible ester oils as an alternative refrigerant. "Hydraulic technology '94.
6. (Published by Nihon Kogyo Publishing).

[0007]

However, since the alternative refrigerant does not contain chlorine, it cannot be expected to have the lubricity as in the conventional specific CFC. For this reason, sliding conditions become severe and high wear resistance is required, but it is made of the above-mentioned high carbon steel, carbon tool steel, chrome molybdenum steel, etc. In such a rolling bearing, sufficient wear resistance cannot be obtained and the fatigue life is reduced.

Generally, in the quenching of bearing steel, the quenching temperature and holding time are strictly selected and controlled. With this, an appropriate amount of pre-spheroidized carbide is left after quenching. When the amount of residual spherical carbides is small, the amount of austenite increases after quenching, and the wear resistance also deteriorates. Bearing steel is said to have the longest life when the residual carbide after quenching is 7 to 8%. To quench, first preheat at a temperature of 600 ℃, then 78
Hold at a temperature of 0 to 840 ° C. for 0.5 to 1 hour, and cool with oil or water. In this case, the presence of retained austenite is unavoidable and usually remains at 5 to 10%, but its presence lowers the hardness and causes deformation due to martensite formation, so it is preferable that the amount is small. Tempering is carried out at a temperature of 200 ° C. or lower for 1 to 2 hours, “Handbook of Metals” (published by Japan Institute of Metals).

[0009] Although tempering causes the bearing steel to be tenacious and prolongs its life, it reduces the hardness of the bearing steel. Corresponding to severe sliding conditions such as the compressor for a refrigerator according to the present invention, it is possible to reduce the degree of tempering more than usual in order to keep the quenching hardness high, but the hardness is the degree of tempering. However, it cannot be said to be sufficient, and even if the wear resistance is somewhat reduced, it cannot be completely resolved.

Moreover, if the hardness by hardening is left high as described above, the residual stress is large, which causes stress corrosion.

The ester oil has a high hygroscopic property, and the absorbed moisture decomposes the ester oil. H ₂ is generated by the decomposition of the ester oil, which penetrates into the steel which is the bearing material to cause stress corrosion, which reduces the bearing life as well as the stress corrosion due to the residual stress.

Therefore, the conventional bearing made of the above-mentioned materials and heat-treated as described above has a short life, and in the case of a hermetic type compressor which is operated without maintenance and has a long life, the life of the bearing is shortened. It becomes a problem because it will be the whole life, and cannot be put to practical use.

An object of the present invention is to solve the above-mentioned problems, and a refrigerating machine for which there is no problem of shortening the service life of the bearing even when a chlorine-free alternative refrigerant and a compatible ester oil are used in combination. It is intended to provide a compressor.

[0014]

In order to achieve the above-mentioned object, the compressor for a refrigerator of the present invention is a mixture of at least one kind or a mixture of two or more kinds of carbon-hydrogen fluoride type refrigerants as a refrigerant. The refrigerant is an ester oil compatible with the refrigerant as a refrigerating machine oil, and is made of steel that supports the force generated in the drive shaft when compressing the refrigerant with a compression mechanism that sucks and compresses the refrigerant by the rotational movement of the drive shaft. In a compressor for a refrigerating machine having a rolling bearing, the rolling bearing and the bearing ring that form the rolling bearing, or both materials, contain a tempering resistant component. .

The tempering resistance component is Si, and 1 to
It is preferable to contain 1.5%.

[0016]

In the above-described structure of the compressor for a refrigerator of the present invention, when the compression mechanism operates due to the rotational movement of the drive shaft, the refrigerant is sucked and compressed to repeat the refrigeration cycle. Refrigerant is at least one or two of carbon-fluoride-based refrigerants
It is a mixed refrigerant that mixes more than one species, does not contain chlorine and does not destroy the environment, is compatible with ester oil that is refrigerating machine oil, and partially compresses it by its own flow through the same passage as refrigerating machine oil. The necessary parts such as the rolling bearing of the mechanism can be carried and supplied to lubricate the necessary parts.

At this time, the refrigerant contains no chlorine and cannot be expected to have lubricity, but a tempering resistant component is contained in both or one of the rolling elements and the bearing rings which form the rolling bearing. As a result, the tempering resistance of the tempering resistance component prevents the hardness from decreasing and achieves high wear resistance, while sufficiently performing the tempering that is normally performed as the above to sufficiently secure the necessary degree of viscosity and remove the residual stress. And the fatigue life is improved,
Improves the life of the bearing because it prevents the stress corrosion due to residual stress and H ₂ generated by decomposition of ester oil due to moisture absorbed to reach the rolling bearing due to the lubrication and hydrogen invades to cause stress corrosion. Even if an alternative refrigerant containing no chlorine and an ester oil compatible therewith are used, there is no problem of shortening the life of the bearing.

The tempering resistance component is preferably Si, and it is effective to contain 1 to 1.5%.

[0019]

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

The refrigerator compressor of the present embodiment is a hermetic compressor, and as shown in FIG. 1 in its entirety, one end side of the interior of the hermetic container 1 constituting a horizontal type pressure container. Is provided with a compression mechanism 2 for sucking and compressing the refrigerant. The stator 4 of the electric motor 3 that drives the compression mechanism 2 is a closed container 1.
Is fixed to the inner surface of the side peripheral wall of the hermetically sealed container 1 and is located at the center of the rotor.
It is arranged so that its axis of rotation is almost 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 portion on the compression mechanism 2 side, and the other end opposite to the main shaft 8. The part is located on the other end side of the closed container 1 and is supported by an auxiliary bearing member 11 fixed to the inner surface of the side wall of the closed container 1. The portion of the main bearing member 10 that supports the main shaft 8 is a plain bearing 9, and the portion of the auxiliary bearing member 11 that supports the other end of the crankshaft 6 is a radial type rolling bearing 12 as shown in FIG. Although the rolling element 31 of the rolling bearing 12 is a ball, it may be a roller or other element if necessary.

These slide bearing 9 and rolling bearing 12
Is for supporting the force generated in the crankshaft 6 when the compression mechanism 2 compresses the refrigerant by the rotational movement of the crankshaft 6, and the rolling bearing 2 is the high carbon chromium steel, carbon tool steel, chromium molybdenum described above. It is made of various steels such as steel.

Adjacent to the rolling bearing 12, a washer 14 is provided on the crankshaft 6 whose movement in the opposite main axis direction is restricted by a snap ring 13. A corrugated washer 15 made of metal is disposed between the washer 14 and the inner ring 32 of the bearing rings 32, 33 of the rolling bearing 12.
The corrugated washer 15 is charged in the axial direction by the rolling bearing 12 and the washer 14 to give an elastic force.

The lower part of the closed container 1 on the end side from the auxiliary bearing member 11 is a lubricating oil reservoir 7, and the upper part is a discharge chamber 21 for discharging the refrigerant gas to the outside of the closed container 1, so that the lubricating oil of the auxiliary bearing member 11 is discharged. A lubricating oil pump 17 driven by the other end of the crankshaft 6 is provided on the side facing the reservoir 7 and screwed. The lubricating oil pump 17 has a suction port 17a opened in the lubricating oil reservoir 7,
A discharge port 17b communicates with a lubricating hole 6a formed in the crankshaft 6 so as to extend vertically from the other end of the crankshaft 6 to the portion of the plain bearing 41. Therefore, the lubricating oil discharged by the lubricating oil pump 17 is first supplied to the plain bearing 41 to lubricate it. Further, the sliding bearing 41 portion is provided in the sliding bearing 9 and the closed container 1 through the passage 23 and the gaps between the respective portions, and the compression mechanism 2 is provided.
And is supplied to the sliding parts of the compression mechanism 2 to lubricate them as well.

The compression mechanism 2 comprises a fixed scroll 2a and a movable scroll 2b, and the passive shaft 2 of the movable scroll 2b.
c is supported at the eccentric position of the main shaft 8 through the slide bearing 41, and the fixed scroll 2a and the movable scroll 2
Some pockets 2d are formed with b. When the movable scroll 2b is swung by the rotation of the crankshaft 6, the pocket 2d receives the refrigerant gas from the suction pipe 18 of the compressor when communicating with the suction port 24 provided on the outer circumference of the fixed scroll 2a. It moves to the side of the discharge port 19 provided in the center of 2a. By this movement, the volume of the pocket 2d is gradually reduced and the refrigerant gas being received is compressed, and the pocket 2d is discharged by the discharge port 19
Discharge this when it leads to. The discharged refrigerant gas is discharged into the closed container 1 through the discharge port 19 and the electric motor side passage 2
It reaches the discharge chamber 21 through 0 and is discharged to the outside of the compressor through the discharge pipe 22 provided in the discharge chamber 21.

With this, when the compression mechanism 2 operates by the rotational movement of the crankshaft 6, the refrigerant gas is sucked and compressed repeatedly, and the refrigeration cycle can be executed.

As the refrigerant gas, a mixed refrigerant in which at least one kind or two or more kinds of the fluorocarbon hydrogen type refrigerant group is mixed is adopted, and since it does not contain chlorine, it does not destroy the environment. Specific examples of such a refrigerant include specific CFC 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 coming out of the sliding bearing 9 into the closed container 1 are the compression mechanism 2 It comes into contact with the refrigerant gas that is sucked into and compressed and discharged into the closed container 1 through the same passage as this, is dissolved and mixed with the refrigerant gas, and accompanies this. Specific examples of such lubricating oil include fatty acid ester and carbonic acid ester.

By entrainment of the lubricating oil in the refrigerant gas,
The refrigerant gas flowing toward the discharge chamber 21 through the electric motor side passage 20 contains lubricating oil, which is carried by its own flow and supplied to the rolling bearing 12, so that it can be lubricated appropriately.

The discharge chamber 21 is formed by partitioning the inside of the closed vessel 1 with a baffle plate 25, and the refrigerant gas that is about to flow into the discharge pipe 22 collides with the baffle plate 25 to perform gas-liquid separation, and thus the refrigerant. The lubricating oil contained in the gas is appropriately separated and collected in the lubricating oil reservoir 7 below.

By the way, as described above, since the alternative refrigerant does not contain chlorine, it cannot be expected to have the lubricity as in the conventional specific CFC. For this reason, sliding conditions become severe and high wear resistance is required, but it is made of the above-mentioned high carbon steel, carbon tool steel, chrome molybdenum steel, etc. In such a rolling bearing, sufficient wear resistance cannot be obtained and the fatigue life is reduced. In addition, ester oil has high hygroscopicity, and the absorbed moisture decomposes the ester oil.
H ₂ is generated by the decomposition of the ester oil, which penetrates into the steel which is the bearing material to cause stress corrosion, which reduces the bearing life as well as the stress corrosion due to the residual stress.

Therefore, in the case of a bearing that has been conventionally heat-treated with the above-mentioned materials, the life is short, and in the case of a hermetic compressor that is operated maintenance-free and has a long life, the life of the bearing is the same as the life of the entire compressor. Therefore, it becomes a problem and cannot be put to practical use.

In order to solve this, in the present embodiment, the rolling element 31 and the bearing rings 32, 3 constituting the rolling bearing 12 are formed.
The material with No. 3 contains a tempering resistant component.

Therefore, the rolling elements 31 and the bearing rings 32, 33 constituting the rolling bearing 12 are sufficiently tempered as a bearing steel to ensure a necessary degree of tenacity and removal of residual stress. While sufficiently achieving it, the tempering resistance of the tempering resistant component prevents hardness decrease and high wear resistance is obtained to improve fatigue life, stress corrosion due to residual stress and moisture absorbed by ester oil. As a result, H ₂ generated by decomposition due to the above is prevented from invading hydrogen into the rolling bearing due to the lubrication and causing stress corrosion, so that the life of the bearing can be improved, and a chlorine-free alternative refrigerant and Even if an ester oil having compatibility with is used, there is no problem of shortening the life of the bearing.

As such a tempering resistant component, "NT
N TECHNICAL REVIEW No. 63 (1
994) ”discloses Si and Al and contains Si 7
For the five types of bearing steels SU2 and A to D in which the ratios of the types of chemical components are changed, the experimental results as shown in the following table are reported.

[0036]

[Table 1]

According to this, it can be seen that the higher the Si content, the longer the life of the bearing.

When used in a compressor using the hydrogen fluoride refrigerant according to the present embodiment, if Si is used, it is 1 to 1.
5% is preferable, and tempering is 200 ° C-27.
It was effective to carry out in the temperature range of 0 ° C.

In this embodiment, the tempering resistant component is contained in both the rolling element 31 and the bearing rings 32, 33 of the rolling bearing 12, but only one of them is contained. However, it is effective as long as one of them becomes long, and belongs to the category of the present invention. It is preferable that the rolling bearing 12 be contained on the side where the life is shortened depending on the specifications, usage conditions and the like. In addition, if there is another similar rolling bearing, it can be applied to this.

[0040]

According to the compressor for a refrigerator of the present invention, the refrigerant to be used is a mixed refrigerant in which at least one kind or a combination of two or more kinds of the fluorocarbon-hydrogen based refrigerant group is mixed and does not contain chlorine and does not damage the environment. However, it is compatible with ester oil, which is a refrigerating machine oil, and it is carried by its own flow to the necessary parts such as rolling bearings of the compression mechanism and supplied, and the necessary parts are lubricated, but at this time, the refrigerant does not contain chlorine. Although lubricity cannot be expected, tempering resistance component is contained in the material of one or both of the rolling elements and bearing rings that make up the rolling bearing. While sufficiently achieving sufficient degree of tenacity and removal of residual stress, the tempering resistance of the tempering resistant component prevents hardness decrease and high wear resistance is obtained, improving fatigue life, Stress decay due to residual stress And, since the H ₂ generated is decomposed by moisture ester oil has moisture absorption is prevented from resulting in ranging in hydrogen infiltrates stress corrosion to the rolling bearing by the lubricant, it is possible to improve the life of the bearing, Even if a chlorine-free alternative refrigerant and an ester oil compatible therewith are used, there is no problem of shortening the life of the bearing.

The tempering resistance component is preferably Si, and it is effective to contain Si in an amount of 1 to 1.5%.

[Brief description of drawings]

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

2 is a partial cross-sectional view of a rolling bearing used in the compressor shown in FIG.

[Explanation of symbols]

 2 compression mechanism 6 crankshaft 8 main shaft 12 rolling bearing 31 rolling elements 32, 33 bearing ring

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hiroshi Matsunaga 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (72) Hirotsugu Fukuoka, 1006, Kadoma, Kadoma City, Osaka

Claims (3)

[Claims] 1. A mixed refrigerant in which at least one kind or a mixture of two or more kinds of carbon-hydrogen fluoride type refrigerant group is mixed as a refrigerant,
A steel rolling bearing that uses an ester oil compatible with the refrigerant as refrigerating machine oil and supports the force generated in the drive shaft when compressing the refrigerant by a compression mechanism that sucks and compresses the refrigerant by the rotational movement of the drive shaft. A compressor for refrigerating machine having: a refrigerating machine compressor, characterized in that a material for at least one of a rolling element and a bearing ring constituting the rolling bearing contains a tempering resistant component. 2. The compressor for a refrigerator according to claim 1, wherein the tempering resistance component is Si. 3. The compressor for a refrigerator according to claim 2, wherein Si is contained in an amount of 1 to 1.5%.