FIELD OF INVENTION

The present invention relates to a compressor.

BACKGROUND OF THE INVENTION

It is known that a compressor includes a motor element housed inside a sealed container, which includes an electric motor stator that is fitted and welded to the sealed container, and welded portions that weld the sealed container and the electric motor stator, as disclosed in International Publication No. WO 2018/150483A1 hereinafter called PTL1.

In PTL1, each weld portion is formed via a recess portion formed between the sealed container and the electric motor stator.

In case that the compressor is installed on a vehicle such as a truck, it may receive large vibration or large impact during movement. If the compressor receives large vibration or large impact, the electric motor stator may shift from the predetermined position. As such, the compressor may affect the performance of the compressor.

Therefore, the development of the compressor that can prevent the electric motor stator from moving from the predetermined position even if the compressor receives large vibration or large impact, is required.

CITATION LIST

Patent Literature

PTL 1: International Publication No. WO 2018/150483A1

SUMMARY OF THE INVENTION

It is an objective of the present inventions to provide a compressor that can prevent the electric motor stator from moving from the predetermined position even if the compressor receives large vibration or large impact.

In order to achieve the above objective, an embodiment of the present invention provides a compressor comprising: a cylindrical sealed container; a compression mechanism accommodated in the sealed container and configured to compress refrigerant gas; a motor element housed inside the sealed container and driving the compression mechanism, which includes an electric motor stator that is fitted and welded to the sealed container; and welded portions that weld the sealed container and the electric motor stator, wherein the compressor includes a contact area that is included in the sealed container and an outer edge portion of the electric motor stator, where an inner circumferential surface of the sealed container and the electric motor stator are in contact and fixed, and wherein the welded portion is formed to extend from the sealed container to the inside of the electric motor stator in the contact area.

According to the embodiment of the present invention, the welded portion is formed to extend from the sealed container to the inside of the electric motor stator in the contact area. Namely, in the contact area, the sealed container and the electric motor stator are welded, as well as the welded portion, the sealed container and the electric motor stator are fixed without gaps therebetween.

Moreover, the welded portion not only welds and fixes the sealed container and the electric motor stator, but also functions as a member for preventing the electric motor stator from moving and shifting with respect to the sealed container.

As such, the sealed container and the electric motor stator are firmly fixed via the welded portion, thereby this can maintain high fixing strength between the sealed container and the electric motor stator.

Therefore, it is possible for the compressor to prevent the electric motor stator from moving from the predetermined position even if the compressor receives large vibration or large impact during movement.

BRIEF DESCRIPTION OF DRAWINGS

The principle of the present invention and its advantages will become apparent in the following description taking in consideration with the accompanying drawings in which:

FIG.1 is an explanation view illustrating a schematic configuration of a compressor 1 including a welded portion 40 according to an embodiment of the present invention;

FIG.2 is a cross sectional view taken along line II- II of FIG.1; and

FIG.3 is an enlarged view about the welded portion 40.

DETAIEED DESCTIPTION OF EMBODIMENTS OF THE INVENTION

Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.

FIG.l is an explanation view illustrating a schematic configuration of a compressor 1 according to the embodiment. The compressor 1 is a fluid machine configured to compress and discharge a fluid (i.e., gas refrigerant), and can be a component of a refrigeration cycle apparatus. The compressor 1 according to the embodiment is a vertically-mounted shell compressor.

As shown in FIG.l, the compressor 1 is a scroll compressor and includes a cylindrical sealed container 10, a suction pipe 12 mounted penetratingly a top face of the sealed container 10 and formed as a hollow cylindrical pipe, a discharge pipe 14 discharging the gas refrigerant to the outside, an injection pipe 15 that guides the intermediate pressure gas refrigerant existing in the refrigerant circuit, a scroll compression mechanism 20 configured to compress a low- pressure gas refrigerant in a compression chamber 28, and a motor element 30 accommodated in the sealed container 10 and configured to drive the compression mechanism 20.

The upper portion of the compression mechanism 20 is supported by a middle shell 10a of the sealed container 10. The compression mechanism 20 is fixed to the middle shell 10a of the sealed container 10 through shrink fitting or other method. A sub-frame 16 is provided below the motor element 30. The sub-frame 16 is fixed to the inner circumferential surface of the sealed container 10. An oil sump 18 is formed on a bottom of the sealed container 10. A refrigerating machine oil lubricating sliding parts such as bearings is accumulated in the oil sump 18.

The suction pipe 12 configured to suck a low-pressure gas refrigerant into the compression mechanism 20 from outside is connected to a side surface of the sealed container 10. The discharge pipe 14 configured to discharge a high-pressure gas refrigerant to the outside of the scroll compressor 1 is connected to the side face of the sealed container 10. The injection pipe 15 guides the intermediate pressure gas refrigerant existing in the refrigerant circuit to the compression chamber 28 of the compression mechanism 20.

The compression mechanism 20 is accommodated in the sealed container 10 and configured to compress the refrigerant sucked from the suction pipe 12 through rotation of a crankshaft 36 that is rotated by the motor element 30. As shown in FIG.l, the compression mechanism 20 includes a fixed scroll 22 and an orbiting scroll 26.

The fixed scroll 22 is fixed to the middle shell 10a at a lower end portion of the fixed scroll 22. As shown in FIG.l, the fixed scroll 22 includes a fixed scroll base plate 22a and a fixed scroll spiral wrap 22b having an involute curve shape so as to form a spiral body and erected on one surface of the fixed scroll base plate 22a. A discharge port 24 configured to discharge a compressed refrigerant is formed in a central part of the fixed scroll 22.

The orbiting scroll 26 is configured to orbit opposed to the fixed scroll 22 without rotating, by a non-illu strated Oldham mechanism. As shown in FIG.l, the orbiting scroll 26 includes an orbiting scroll base plate 26a and an orbiting scroll spiral wrap 26b having an involute curve shape so as to form a spiral body and erected on one surface of the orbiting scroll base plate 26a. An orbiting bearing 26c formed in a bottomed cylindrical shape is formed in a substantially central part on an undersurface of the orbiting scroll base plate 26a. An eccentric shaft portion 36b installed on an upper end of a main shaft portion 36a described later is inserted in the orbiting bearing 26c, in order to cause the orbiting scroll 26 to orbit.

The orbiting scroll spiral wrap 26b is configured to be engaged with the fixed scroll spiral wrap 22b to form the compression chamber 28 between the fixed scroll spiral wrap 22b and the orbiting scroll spiral wrap 26b. The orbiting scroll 26 is configured to orbit opposed to the fixed scroll 22.

As shown in FIG.2, the motor element 30 includes an electric motor stator 32 fixed to the inner circumferential surface of the sealed container 10 through shrink fit or other method, an electric motor rotor 34 rotatably housed on an inner circumferential side of the electric motor stator 32, and the crankshaft 36 (main shaft portion 36a) fixed to the electric motor rotor 34 through shrink fit or other method.

The electric motor stator 32 is connected to a glass terminal 37 via lead wires. The electric motor stator 32 is supplied with electric power from outside via the glass terminal 37 and lead wires. The electric motor rotor 34 is configured to rotate as electric power is supplied to the electric motor stator 32 and transmit a driving force to the orbiting scroll 26 through the crankshaft 36.

The electric motor stator 32 is fixed to the inner circumferential surface of the sealed container 10 by being fitted and welded to the sealed container 10. The electric motor stator 32 has multiple layers of coils 38 made via an insulator (not shown). The coils 38 are arranged in multiple openings 32a formed along the inner circumferential surface of the electric motor stator 32 when viewed from above. In this embodiment, the number of the openings is 18. The coil 38 is coated with an insulating coating material.

The electric motor stator 32 is made of electrical steel, which is a high magnetic permeability material. The material of the electromagnetic steel is, for example, silicon steel.

As shown in FIG.2, in the sealed container 10 and an outer edge portion of the electric motor stator 32, the sealed container 10 and the electric motor stator 32 include a contact area 50 where the inner peripheral surface of the sealed container 10 and the electric motor stator 32 are in contact with each other, and a non-contact area where the inner peripheral surface of the sealed container 10 and the electric motor stator 32 are not in contact with each other. The contact area 50 is the area colored in gray in FIG.2 and FIGG.

Namely, the contact area 50 is included in the sealed container 10 and an outer edge portion of the electric motor stator 32, where an inner circumferential surface of the sealed container 10 and the electric motor stator 32 are in contact and fixed. At least one gap 52 through which compressed gas flows between the electric motor stator 32 and an inner circumferential surface of the sealed container 10, is provided in the non-contact area that is an area other than the contact area 50.

As shown in FIG.2 and FIG.3, welded portions 40 are formed to weld the middle of shell 10a of the sealed container 10 and the electric motor stator 32. The welded portion 40 is formed to be located in the contact area 50 and formed to extend from the sealed container 10 to the inside of the electric motor stator 32 in the contact area 50.

In this embodiment, a number of the welded portions 40 is 4, for the purpose of ensuring high fixing strength between the sealed container 10 and the electric motor stator 32. The number of welded portions 40 is not limited to 4, and may be, for example, 1 to 3, 5 or more. Moreover, the welded portions 40 may be formed at different height positions.

The welded portion 40 is formed to extend from the sealed container 10 to the inside of the electric motor stator 32 so that the tip on the electric motor stator 32 side is curved, when viewed from above.

In case that a radius of curvature of the welded portion 40 on the motor stator side is large, when the compressor 1 receives large vibration or large impact, there is possible that the fixing strength between the sealed container 10 and the motor electric stator 32 becomes insufficient, thereby the crack may occur around the welded portion 40.

In this embodiment, the radius of curvature of the welded portion 40 on an electric motor stator side is less than the radius of curvature of both the sealed container 10 and the electric motor stator 32, from the viewpoint of preventing cracks from forming around the welded portion 40 when the compressor 1 receives large vibration or large impact.

The eccentric shaft portion 36b located above the electric motor rotor 34 in the crankshaft 36 is rotatably supported in a radial direction by the cylindrical orbiting bearing 26c installed under the orbiting scroll base plate 26a. The main shaft portion 36a is fitted in a main bearing 39 and slides along the main bearing 39 by an oil film of a lubricating oil. The eccentric shaft portion 36b eccentric to the main shaft portion 36a is installed on the upper end of the crankshaft 36.

A pump element 19 such as a positive displacement pump is installed at a lower end of the crankshaft 36. The pump element 19 supplies the refrigerating machine oil accumulated in the oil sump 18 to the sliding parts such as the main bearing 39. The pump element 19 is mounted on the sub-frame 16 and supports the crankshaft 36 in the axial direction on an upper end surface of the pump element 19. Next, a method for fixing the electric motor stator 32 into the sealed container 10 is described.

Firstly, the electric motor stator 32 is inserted into the sealed container 10 so that each gap 52 is located in the non-contact area other than the contact area 50. As such, an arc spot welding can be performed from the outside of the sealed container 10 so that welded portions 40 can be formed in the contact area 50 at a later step.

Secondly, the electric motor stator 32 is fitted into the sealed container 10. The fitting of the sealed container 10 and the electric motor stator 32 is preferably press-fitting or shrink fitting.

Thirdly, the arc spot welding is performed to weld the electric motor stator 32 and the sealed container 10. In the arc spot welding, the metal members in contact with each other and a welded metal rod are melted by arc discharge, and the melted metal fills the melted part of the metal parts that are in contact with each other. As such, by solidifying the melted metal, the welded portion 40 for welding the sealed container 10 and the stator in the contact area 50, is formed.

The welding method between the sealed container 10 and the electric motor stator 32 is not limited to the arc spot welding, and other welding methods such as a laser welding may be used.

Next, an operation of the compressor 1 including the welded portions 40 between the sealed container 10 and the electric motor stator 32 is described in details with reference to FIG.1 to FIG.3. In the following, a case where the compressor is installed on a vehicle such as a truck will be described as an example.

While the compressor 1 is in operation, the compressed refrigerant is discharged from the discharge port 24 to the discharge pipe 14 through each gap 52 between the sealed container 10 and the electric motor stator 32 in the non-contact area.

During movement of the vehicle, there are cases where the compressor 1 receives the large vibration or large impact.

In this embodiment, the welded portion 40 is formed to extend from the sealed container 10 to the inside of the electric motor stator 32 in the contact area 50. Namely, in the contact area 50, the sealed container 10 and the electric motor stator 32 are welded, as well as the welded portion 40, the sealed container 10 and the electric motor stator 32 are fixed without gaps therebetween.

Also, at least one gap 52 through which compressed gas flows between the electric motor stator 32 and an inner circumferential surface of the sealed container 10, is provided in the noncontact area that is other than the contact area 50. Namely, the welded portion 40 is not included in the non-contact area. Therefore, the compressor 1 surely enables to maintain the high fixing strength of the sealed container 10 and the motor stator.

Moreover, the welded portion 40 in the contact area 50 not only welds and fixes the sealed container 10 and the electric motor stator 32, but also functions as a member for preventing the electric motor stator 32 from moving and shifting with respect to the sealed container 10.

Furthermore, since the number of the welded portions 40 is 4, it is possible to ensure high fixing strength between the sealed container 10 and the electric motor stator 32, even if the compressor 1 receives the large vibration or large impact.

As such, the sealed container 10 and the electric motor stator 32 are firmly fixed via the welded portion 40, thereby this can maintain high fixing strength between the sealed container 10 and the electric motor stator 32.

Therefore, it is possible for the compressor 1 to prevent the electric motor stator 32 from moving from the predetermined position even if the compressor 1 receives large vibration or large impact during movement.

Although specific embodiments of the invention have been disclosed and described as well as illustrated in the companying drawings, it is simply for the purpose of better understanding of the principle of the present invention and it is not as a limitation of the scope and spirit of the teaching of the present invention. Adaption and modification to various structures such as design or material of the invention, mounting mechanism of various parts and elements or embodiments are possible and apparent to a skilled person without departing from the scope of the present invention which is to be determined by the claims.

List of reference:

1: compressor

10: sealed container

10a: middle shell

12: suction pipe

14: discharge pipe

15: injection pipe

16: sub-frame

18: oil sump

19: pump element

20: compression mechanism : fixed scroll a: fixed scroll base plateb: fixed scroll spiral wrap: discharge port : orbiting scroll a: orbiting scroll base plateb: orbiting scroll spiral wrapc: orbiting bearing : compression chamber : motor element : electric motor stator a: opening : electric motor rotor : crankshaft a: main shaft portion b: eccentric shaft portion: glass terminal : coil : main bearing : welded portion : contact area : gap