KR100947420B1 - Scroll compressor - Google Patents

Abstract

In a scroll compressor, a low carbon steel having high machinability and good weldability, and a high wear resistance by a gas soft nitriding treatment, are intended to be inexpensive and to improve reliability.

In order to solve this, the scroll compressor 50 is equipped with the electric motor part 5, the compression mechanism part 6, the crankshaft 11, the bearing, and the airtight container 1. As shown in FIG. The bearing has a main bearing 13 and a sub bearing 14. The sub-bearing 14 is welded to the support portion and has a bearing housing 15 having an inner surface portion 15a on the inner circumference thereof, and an outer surface portion 16b having an automatic shaft alignment function by sliding with the inner surface portion 15a. It is provided with a spherical bearing 16 having. The spherical bearing 16 is constituted by nitriding and hardening the surface of a carbon steel or cast material for mechanical structure, and further performing molybdenum sulfide and manganese phosphate coating. The bearing housing 15 is constituted by using a low carbon steel material and performing gas soft nitridation on at least an inner surface portion that is a sliding surface with at least the outer surface portion 16b of the spherical bearing 16 on its surface.

Spherical bearing, spherical bearing, automatic shaft alignment, bearing housing, low carbon steel

Description

Scroll Compressor {SCROLL COMPRESSOR}

TECHNICAL FIELD This invention relates to a scroll compressor. Specifically, it is suitable for the scroll compressor mounted in an air conditioner, a refrigerator, etc.

As a conventional scroll compressor, there exists a thing of Unexamined-Japanese-Patent No. 6-173877 (patent document 1).

The scroll compressor of Patent Document 1 includes an electric motor portion, a compression mechanism portion for compressing a working fluid, a crank shaft for transmitting the rotational force of the motor portion to the compression mechanism portion, and driving the compression mechanism portion, and the crank shaft. A plurality of bearings rotatably supported at both sides of the motor portion, and a sealed container for storing the motor portion, the compression mechanism portion, the crankshaft, and the plurality of bearings.

The compression mechanism unit includes a fixed scroll and swing scroll for forming a compression chamber by engaging spiral wraps provided on each end plate, a rotation preventing means for the swing scroll, and a frame for supporting the rotation prevention means. Equipped with. The said plurality of bearings are equipped with the main bearing which is built in the said frame, and supports the said crankshaft, and the sub bearing which supports the said crankshaft on the opposite side to a compression mechanism part rather than the said electric motor part. The sub-bearing is provided with a bearing housing welded to the support portion and having a spherical shape at its inner circumference, and a spherical bearing accommodated in the spherical shape of the bearing housing and having an automatic shaft alignment function to support the crankshaft.

In addition, the spherical bearing is formed by nitriding and hardening the surface of a carbon steel or cast material for mechanical structure, and further performing molybdenum sulfide and manganese phosphate coating.

<Patent Document 1> Japanese Unexamined Patent Publication No. 6-173877

Patent Document 1 uses a spherical bearing formed by nitriding and hardening the surface of a carbon steel or cast material for mechanical structure, and by applying a molybdenum sulfide and manganese phosphate coating, so that the surface hardness is enhanced and the spherical bearing The reliability of the is improved. However, Patent Document 1 does not disclose the reliability of the bearing housing.

Mechanical bearing carbon steel is used for the bearing housing, but when the carbon content of the bearing housing is large, cracks are likely to occur in the bearing housing when welded to the support portion, resulting in inferior machining accuracy. Therefore, in order to give priority to crack prevention during welding and improvement of machining accuracy, it is conceivable to use a low carbon steel material for the bearing housing, but in that case, there are significant differences in the hardness difference and the wear resistance between the bearing housing and the spherical bearing. It has been found that the bearing housing may be abnormally worn unilaterally due to operation or the like, which may cause noise abnormality and deterioration of the compressor quality such as increased input.

It is an object of the present invention to provide a low cost and reliable scroll compressor using a low carbon steel having high machinability and good weldability and having a high wear resistance by gas soft nitriding treatment.

In order to achieve the above object, the present invention provides an electric motor unit, a compression mechanism unit for compressing a working fluid, a crank shaft for transmitting the rotational force of the motor unit to the compression mechanism unit to drive the compression mechanism unit, and the crank shaft. A plurality of bearings rotatably supported on both sides of the electric motor part, and a sealed container in which the electric motor part, the compression mechanism part, the crankshaft, and the plurality of bearings are housed, wherein the compression mechanism parts are respectively end portions. A fixed scroll and a pivoting scroll which form a compression chamber by engaging a spiral wrap provided on a plate, a rotation preventing means of said pivoting scroll, and a frame supporting said rotation preventing means, said plurality of bearings comprising: A main bearing embedded in the frame and supporting the crankshaft, and a compression mechanism portion rather than the electric motor portion; And a sub-bearing supporting the crankshaft, wherein the sub-bearing is welded to the support and simultaneously has a bearing housing having an inner surface portion at an inner circumference thereof, and is accommodated in the bearing housing and slides with the inner surface portion to provide automatic shaft alignment. A spherical bearing having a spherical bearing having an outer spherical shape, wherein the spherical bearing is formed by performing a nitriding treatment on the surface of a carbon steel or a casting material for mechanical structure to harden it, and further performing a molybdenum sulfide and manganese phosphate coating. In the bearing housing, a low carbon steel material is used, and a gas soft nitridation treatment is provided on an inner surface portion that is a sliding surface of at least the outer surface portion of the spherical bearing.

A more preferable specific structural example of this invention is as follows.

(1) The bearing housing is made of a low carbon steel having a carbon content of less than 0.25%.

(2) The hardness of the surface layer of the said bearing housing is 400 Hv or more.

According to such a scroll compressor of the present invention, a low-carbon steel having high machinability and good weldability and a high wear resistance by gas soft nitridation treatment can be inexpensively improved in reliability.

EMBODIMENT OF THE INVENTION Hereinafter, one Embodiment in this invention is described, referring FIGS. 1 is a longitudinal cross-sectional view of a scroll compressor of one embodiment of the present invention, FIG. 2 is an enlarged view of a sub-bearing part of the scroll compressor of FIG. 1, and FIG. 3 is a partially enlarged cross-sectional view of the bearing housing of FIG.

The scroll compressor 50 transmits the electric motor part 5, the compression mechanism part 6 which compresses a working fluid, and the rotational force of the electric motor part 5 to the compression mechanism part 6, and the said compression mechanism part 6 is calculated | required. The same crankshaft 11, the plurality of bearings 12 to 14 which rotatably support the crankshaft 11 at both sides of the electric motor part 5, the lubricating oil 2, and the airtight container which accommodates these ( 1) is provided.

The electric motor part 5 consists of the rotor 3 which penetrated the crankshaft 11 in the center, and the stator 4 which the outer periphery welded to the airtight container 1, and was fixed.

The compression mechanism part 6 engages spiral wraps provided on each end plate to prevent rotation of the fixed scroll 7 and the revolving scroll 8, which form the compression chamber, and the revolving scroll 8, respectively. An old wall ring 9 constituting an anti-rotation means to allow idle, and a frame 10 for supporting the swinging scroll 8 and the old wall ring 9 are provided.

The crankshaft 11 has an eccentric part 11a at one side end part, fits the eccentric part 11a to the boss | hub part of the turning scroll 8, and rotates the rotational force of the electric motor part 5 with the turning scroll 8 ) To orbit the turning scroll (8). In the central part of the crankshaft 11, the oil supply hole 11b for supplying the lubricating oil 2 stored in the bottom part of the airtight container 1 to the sliding parts of the bearings 12-14 and the compression mechanism part 6 is provided. Formed.

The plurality of bearings 12 to 14 are embedded in the boss portion of the swinging scroll 8 to support the eccentric portion 11a of the crankshaft 11, and the cranks embedded in the frame 10. The main bearing 13 which supports the shaft 11, and the sub bearing 14 which supports the crankshaft 11 on the opposite side to the compression mechanism part rather than the electric motor part 5 are comprised. Swivel bearing 12 and main bearing 13 are comprised by the cylindrical sliding bearing.

The sub-bearing 14 has the bearing housing 15 which has the durable surface part 15a in the inner periphery, and the sliding surface 16a accommodated in the bearing housing 15, and supports the crankshaft 11 in the inner periphery, It is comprised by the sliding bearing which consists of the spherical bearing 16 which has the outer peripheral surface part 16b which has an outer-surface part 16b which slides with the inner surface part 15a on an outer periphery, and has an automatic axis alignment function. According to such a structure, since the crankshaft 11 can change a posture freely by the automatic axis alignment function in the sub-bearing 14, it absorbs the inclination of the crankshaft 11 at the time of assembly, and aims at improving assembly property. can do. Similarly, the deflection of the crankshaft 11 in operation is absorbed, thereby preventing the bias of an abnormal load and improving reliability.

Moreover, the bearing housing 15 is welded and fixed to the lower surface of the inner peripheral part of the housing support member 17. The outer circumferential portion of the housing support member 17 is welded to the sealed container 1 and fixed. Therefore, the bearing housing 15 is supported by the sealed container 1 through the housing support member 17.

The scroll compressor 50 performs the compression work by following the compression mechanism part 6 by the rotational power of the electric motor part 5. Thereby, the crankshaft 11 which transmits the rotation of the electric motor part 5, and the spherical bearing 16-bearing housing of the main bearing 13 and the sub bearing 14 which support this crankshaft 11 ( 15), it is necessary to maintain the load due to the compression work and the load due to the movement of the movable parts. Therefore, each sliding part requires strength and abrasion resistance.

As mentioned above, the spherical bearing 16 has the sliding surface 16a which is a sliding surface with the journal part of the crankshaft 11 on the inner periphery, and has the inner surface 15a of the bearing housing 15 on the outer periphery. It has the outer peripheral surface part 16b which is a sliding surface. Therefore, the spherical bearing 16 is unfixedly supported and has a sliding surface on both the inner circumference and the outer circumference. The fixed bearing receives both the load and the circumferential speed of the crankshaft 11 only by the inner circumferential surface, whereas the unfixed spherical bearing 16 carries the load and the circumferential speed of the crankshaft 11 with the inner circumferential surface 16a and the outer circumferential surface 16b. It is possible to receive each with). That is, when the spherical bearing 16 rotates at the same rotational direction as the crankshaft 11 rotates at a lower rotational speed than the crankshaft 11, the spherical bearing 16 rotates the circumferential speed of the crankshaft 11. Can be received by two surfaces of the inner circumferential surface 16a and the outer circumferential surface 16b, and heat generation of the crankshaft 11 can be suppressed.

However, in the two sliding surfaces 16a and 16b of the spherical bearing 16, a difference arises in lubricity, surface roughness, or the like, for example, the spherical bearing 16 has a rotation speed almost equal to that of the crankshaft 11 or the like. At a rotational speed close to, the load and circumferential speed are concentrated on the outer surface of the spherical bearing 16 and the inner surface of the bearing housing 15. For this reason, it is necessary to consider that the surface of the sliding surface 16b of the spherical bearing 16 and the surface of the sliding surface 15a of the bearing housing 15 can cope with the load.

Here, the spherical bearing 16 is constituted by nitriding and hardening the surface of the carbon steel or cast material for mechanical structure, and further performing molybdenum sulfide and manganese phosphate coating, thereby improving the surface hardness. However, the bearing housing 15 preferably uses a low carbon steel in consideration of free machinability and weldability. For this reason, while the surface hardness of the spherical bearing 16 is 400-600 Hv, when the low carbon steel S20C is simply used as the bearing housing 15, the surface hardness of the bearing housing 15 is about 120-160 Hv. As a result, the surface hardness greatly differs in these sliding surfaces. In this state, if the load is concentrated on the sliding surface 16b of the spherical bearing 16 and the sliding surface 15a of the bearing housing 15 as described above, the bearing housing 15 wears due to the difference in surface hardness. This may impair reliability.

Therefore, in this embodiment, in order to improve the reliability by increasing the hardness of the bearing housing 15, at least the inner surface part 15a of the bearing housing 15 is subjected to gas softening treatment. Fig. 3 shows a cross sectional view of the vicinity of the surface when gas soft nitriding is performed on the bearing housing 15. Figs. As schematically shown in Fig. 3, a diffusion layer 15c of nitrogen is generated in the vicinity of the surface of the raw material portion 15b of the bearing housing 15, and a compound layer 15d is formed on the surface thereof. By this diffusion layer 15c, the hardness of the bearing housing 15 is increased, and reliability can be improved, and the spherical bearing 16 can be rotated at a lower speed than the rotation of the crankshaft 11. .

Further, the processing temperature required for the gas soft nitridation treatment is about 500 to 600 ° C., which is lower than the processing temperature required for carburizing quenching or high frequency quenching, which is another surface hardening method, and is 800 ° C. to 900 ° C., and the A3 transformation point of low carbon steel (about 850 to 900). It is also low enough compared to Therefore, a large dimensional change of the bearing housing 15 of this embodiment does not occur, and the shape of the inner surface part 15a of the bearing housing 15 can be maintained, and the dimensional clearance with the spherical bearing 16 is processed before processing. Can be determined by machining. Thereby, since the fall of the reliability by the local sliding movement by a local dimensional change is suppressed and a post process is not needed, the sub bearing 14 which is inexpensive and highly reliable can be attained.

According to this embodiment, it is possible to provide a scroll compressor having low cost and high reliability by using a low carbon steel having high machinability and good weldability and by using a gas soft nitriding treatment as a bearing housing having high wear resistance.

1 is a longitudinal sectional view of a scroll compressor of one embodiment of the present invention;

2 is an enlarged view of a sub-bearing part of the scroll compressor of FIG.

3 is a partially enlarged cross sectional view of the bearing housing of FIG. 2;

<Explanation of symbols for the main parts of the drawings>

1: sealed container

2: lubricating oil

3: rotor

4: stator

5: motor part

6: compression mechanism

7: fixed scroll

8: turning scroll

9: olddam ring (anti-rotation means)

10: frame

11: crankshaft

12: slewing bearing

13: main bearing

14: vice bearing

15: bearing housing

15a: Durable surface part

16: spherical bearing

16a: inner circumference

16b: outer surface part

17: housing support member (support)

50: scroll compressor

Claims (3)

Electric motor part, A compression mechanism portion for compressing the working fluid, A crankshaft which transmits the rotational force of the electric motor part to the compression mechanism part and drives the compression mechanism part; A plurality of bearings rotatably supporting the crankshaft on both sides of the electric motor unit; A sealed container in which the electric motor portion, the compression mechanism portion, the crankshaft, and the plurality of bearings are housed, The compression mechanism section includes a fixed scroll and a swing scroll for forming a compression chamber by engaging spiral wraps provided on each end plate, a rotation preventing means for the swing scroll, and a frame for supporting the rotation preventing means. and, The plurality of bearings include a main bearing embedded in the frame and supporting the crankshaft, and a sub-bearing supporting the crankshaft on the opposite side of the compression mechanism portion than the electric motor portion. The sub-bearing includes a bearing housing welded to the support portion and having an inner circumferential portion at an inner circumference, and a spherical bearing having an outer circumferential shape that is housed in the bearing housing and slides with the inner circumferential portion to have an automatic shaft alignment function. In the scroll compressor, the spherical bearing is formed by performing a nitriding treatment on the surface of a carbon steel or casting material for mechanical structure, and performing a molybdenum sulfide and manganese phosphate coating. The said bearing housing is a scroll compressor characterized by using a low carbon steel material and performing gas soft nitriding on the inner surface which becomes a sliding surface with the outer surface part of the said spherical bearing at least on the surface. The scroll compressor according to claim 1, wherein the bearing housing is made of a low carbon steel having 0% <carbon content <0.25%. The scroll compressor according to claim 1, wherein the hardness of the surface layer of the bearing housing is 400Hv or more and 600Hv or less.

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