MOTOR COMPRESSOR

Abstract

An object is to maintain housings at equal potentials. Facing insertion holes are formed on mating surfaces of a front housing and a center housing. One end and the other end of a spring pin are inserted into the insertion holes, respectively, and an outer peripheral surface is pressed against inner peripheral surfaces of the insertion holes by an elastic force.

Description

TECHNICAL FIELD

The present invention relates to a motor compressor.

BACKGROUND ART

In a motor compressor, an inverter accommodation portion and a cover are insulated by a gasket. PTL 1 proposes that a projection portion formed in the inverter accommodation portion is brought into contact with the cover to maintain both at equal potentials.

CITATION LIST

Patent Literature

PTL 1: JP 2015-17577 A

SUMMARY OF INVENTION

Technical Problem

The motor compressor is formed by assembling a plurality of housings, and each housing is also insulated by a gasket. Therefore, it is necessary to take measures to maintain each housing at equal potentials.

An object of the present invention is to maintain the housings at equal potentials.

Solution to Problem

A motor compressor according to an aspect of the present invention includes: a first housing and a second housing each made of metal, and configured to be insulated from each other by interposing a gasket between mating surfaces, in which facing insertion holes are formed in portions of the mating surfaces where the gasket is not provided; and an insertion member made of metal, and having one end and the other end which are inserted into the insertion holes, respectively, and an outer peripheral surface which is pressed against inner peripheral surfaces of the insertion holes by an elastic force.

Advantageous Effects of Invention

According to the present invention, since the outer peripheral surface of the insertion member is pressed against the inner peripheral surface of the insertion hole by the elastic force, sufficient surface contact can be maintained and the housings can be maintained at equal potentials.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a cross-sectional view of a compressor along an axial direction;

FIG. 2 is a diagram illustrating a spring pin; and

FIGS. 3A and 3B are diagrams each illustrating a comparative example.

DESCRIPTION OF EMBODIMENTS

Hereinafter, embodiments of the present invention will be described with reference to the drawings. Each drawing is a schematic one and may differ from the actual one. In addition, the following embodiments exemplify a device and a method for embodying a technical idea of the present invention, and do not specify a configuration to the following. That is, the technical idea of the present invention can be modified in various ways within the technical scope described in Claims.

One Embodiment

<<Configuration>>

FIG. 1 is a cross-sectional view of a compressor along an axial direction.

A compressor 11 is, for example, a motor compressor used in a refrigerant circuit of a car air conditioner, sucks a refrigerant, compresses the refrigerant, and then discharges the refrigerant.

In the following description, for convenience, one side in the axial direction of the compressor 11 is referred to as a front side, and the other side in the axial direction is referred to as a rear side.

The compressor 11 is integrated with a front housing 12, a center housing 13, and a rear housing 14 disposed in order from the front side along the axial direction to maintain airtightness. The front housing 12 is formed with a suction port (not illustrated) for sucking the refrigerant, and the rear housing 14 is formed with a discharge port (not illustrated) for discharging the compressed refrigerant.

The front housing 12 includes a suction chamber 21 communicating with the suction port (not illustrated), and an electric motor 22 is housed in the suction chamber 21. A rotating shaft 23 of the electric motor 22 is rotatably supported on the front side by the front housing 12 and is rotatably supported on the rear side by the center housing 13.

A fixed scroll 24 and a movable scroll 25 are housed in the center housing 13.

The fixed scroll 24 is fixed to close the rear side of the front housing 12, and includes a fixed endplate 26 formed in a disk shape and a fixed spiral 27 formed on a front surface of the fixed end plate 26.

The movable scroll 25 is disposed on the front side of the fixed end plate 26, and includes a movable end plate 28 formed in a disk shape and a movable spiral 29 formed on a rear surface of the movable endplate 28 and meshing with the fixed spiral 27.

The front surface of the fixed endplate 26 and the rear surface of the movable end plate 28 face each other, and the fixed spiral 27 and the movable spiral 29 mesh with each other. A tip end of the fixed spiral 27 slidably contacts the rear surface of the movable end plate 28 via a tip seal (not illustrated), and a tip end of the movable spiral 29 slidably contacts the front surface of the fixed end plate 26. A compression chamber 31 for compressing the refrigerant is formed by a section surrounded by the front surface of the fixed end plate 26, the fixed spiral 27, the rear surface of the movable end plate 28, and the movable spiral 29. When viewed from a front-rear direction, the compression chamber 31 is a crescent-shaped closed space.

A back pressure chamber 32 is formed on a front side of the movable scroll 25. By supplying oil of intermediate pressure to the back pressure chamber 32, the movable scroll 25 is pressed against the fixed scroll 24 to improve the airtightness of the compression chamber 31.

A boss 33 is formed on a front surface of the movable end plate 28, an eccentric crank end portion 34 is formed on the rear end of the rotating shaft 23, and the crank end portion 34 is rotatably fitted into the boss 33. The rotational movement of the rotating shaft 23 is transmitted to the movable scroll 25 as a turning movement by the crank end portion 34. The movable scroll 25 is prevented from rotating through, for example, a pin and a hole, and is allowed to revolve with respect to the fixed scroll 24.

A discharge hole 35 penetrating in the front-rear direction is formed in the center of the fixed end plate 26, and the discharge hole 35 communicates with a discharge chamber 36 formed on the rear side of the fixed endplate 26. A discharge valve 37 that can open and close the rear end side of the discharge hole 35 is provided on a rear surface of the fixed end plate 26.

When the movable scroll 25 revolves with respect to the fixed scroll 24, the compression chamber 31 is displaced toward the scroll center when viewed from the front-rear direction, and the volume is reduced. When the compression chamber 31 is outside the scroll, the compression chamber 31 communicates with a suction port (not illustrated) to suck the refrigerant. When the compression chamber 31 is in the center of the scroll, the compression chamber 31 communicates with the discharge hole 35 to discharge the compressed refrigerant. When the discharge valve 37 receives the discharge pressure, the discharge valve 37 discharges the refrigerant into the discharge chamber 36. The discharged refrigerant is discharged to the outside from a discharge port (not illustrated).

Next, an equipotential structure of each housing will be described.

The front housing 12 (first housing), the center housing 13 (second housing), and the rear housing 14 (third housing) are all made of metal. The front housing 12 and the center housing 13 are insulated from each other by interposing a gasket 41 whose surface layer is rubber between the mating surfaces. The center housing 13 and the rear housing are insulated from each other by interposing a gasket 42 whose surface layer is rubber between the mating surfaces. The front housing 12 and the rear housing 14 are fastened with bolt 43 with the center housing 13 interposed therebetween. An inserting hole 44 having a diameter larger than that of the bolt 43 is formed in the center housing 13, the bolt 43 is inserted into the inserting hole 44, and each housing is assembled.

Therefore, the front housing 12 and the rear housing 14 are maintained at equal potentials by the bolt 43. On the other hand, in the center housing 13, since the bolt 43 is loosely inserted into the inserting hole 44, a contact state is not stable and the equipotential is not guaranteed. The front housing 12 and the center housing 13 are connected by a spring pin 45 (insertion member), and the equipotential is maintained.

FIG. 2 is a diagram illustrating a spring pin.

Facing insertion holes 46 are formed on the mating surfaces of the front housing 12 and the center housing 13, respectively. The two insertion holes 46 have the same diameter and are formed coaxially. The diameter of the insertion hole 46 is slightly smaller than the outer diameter of the spring pin 45. The gasket 41 is formed with an opening portion 47 (portion without a gasket) penetrating from the front housing 12 side to the center housing 13 side at a position corresponding to the insertion holes 46.

The spring pin 45 is used for positioning in the circumferential direction when fixing the front housing 12 and the center housing 13, and one end and the other end are inserted into the respective insertion holes 46. The spring pin 45 is formed by winding a thin plate in a cylindrical shape, and includes a cut line 48 along the axial direction. When no load is applied from the outside, since the cut line 48 is separated in the circumferential direction, the spring pin 45 has a substantially C shape when viewed from the axial direction. The outer diameter of the spring pin 45 is wide open toward the rear side in the axial direction, and is slightly larger than that of the insertion hole 46. When inserting the spring pin 45 into the insertion hole 46, a load in the diameter reduction direction is applied to the spring pin 45 and the spring pin 45 is press-fitted so that the cut line 48 is eliminated. The spring pin 45 inserted into the insertion hole 46 is fixed to the insertion hole 46 by the action of a force that tries to spread. The outer peripheral surface of the spring pin 45 is pressed against the inner peripheral surfaces of the insertion holes 46 by an elastic force, and a stable surface contact state is established.

<<Action>>

Next, the main action and effect of one embodiment will be described.

The front housing 12 and the center housing 13 are insulated by the gasket 41, and the center housing 13 and the rear housing 14 are insulated by the gasket 42. However, the compressor 11 is required to maintain each housing at equal potentials. The front housing 12 and the rear housing 14 are maintained at equal potentials by the bolt 43. On the other hand, in the center housing 13, since the bolt 43 is loosely inserted into the inserting hole 44, a contact state is not stable and the equipotential is not guaranteed.

Therefore, the front housing 12 and the center housing 13 are connected by the spring pin 45. That is, the facing insertion holes 46 are formed on the mating surfaces of the front housing 12 and the center housing 13, respectively, and one end and the other end of the spring pin 45 are inserted into the respective insertion holes 46. The spring pin 45 inserted into the insertion hole 46 is kept in sufficient surface contact because the outer peripheral surface of the spring pin 45 is pressed against the inner peripheral surface of the insertion hole 46 by the action of a force that tries to spread. Therefore, the front housing 12 and the center housing 13 can be maintained at equal potentials.

The front housing 12 and the center housing 13 are originally formed with the insertion holes 46 for inserting solid pins (also referred to as knock pins) for positioning in the circumferential direction. Therefore, the solid pin to be inserted into the insertion hole 46 may only be changed to the spring pin 45.

Here, a comparative example will be described.

FIGS. 3A and 3B are diagrams each illustrating a comparative example.

FIG. 3A illustrates a case where a solid pin 51 is used. Since the solid pin 51 is a simple columnar member and does not press the outer peripheral surface against the inner peripheral surfaces of the insertion holes 46 by an elastic force, the action and effect as in the present embodiment cannot be obtained. In a case of light press-fitting, an equipotential value is unstable due to vibration fretting because there is no pressing force. In addition, in a case of strong press-fitting, there is a concern that galling of the pin and housing may occur in production.

FIG. 3B illustrates a case where the solid pin 51 is used and the centers of the insertion holes 46 are intentionally shifted from each other. As a result, both ends of the solid pin 51 can be brought into line contact with the inner peripheral surfaces of the insertion holes 46. However, since the outer peripheral surface of the solid pin 51 is not pressed against the inner peripheral surfaces of the insertion holes 46 by an elastic force, the action and effect as in the present embodiment cannot be obtained. Specifically, when a continuity test was performed, it was found that the resistance value may not be a predetermined threshold value (for example, 10 mΩ) or less, and the resistance value varied widely.

<<Modification>>

In the present embodiment, the spring pin 45 is used, and the present invention is not limited thereto. For example, a leaf spring portion may be formed at the tip end of the pin so that the leaf spring portion elastically deforms and comes into surface contact with the inner peripheral surface of the insertion hole 46. As described above, any shape can be used as long as the outer peripheral surface of the insertion member is pressed against the inner peripheral surface of the insertion hole by an elastic force.

Hereinbefore, although described with reference to a limited number of embodiments, the scope of rights is not limited thereto, and modifications of the embodiments based on the above disclosure are obvious to those skilled in the art.

REFERENCE SIGNS LIST

• • 11 compressor
  • 12 front housing
  • 13 center housing
  • 14 rear housing
  • 21 suction chamber
  • 22 electric motor
  • 23 rotating shaft
  • 24 fixed scroll
  • 25 movable scroll
  • 26 fixed end plate
  • 27 fixed spiral
  • 28 movable end plate
  • 29 movable spiral
  • 31 compression chamber
  • 32 back pressure chamber
  • 33 boss
  • 34 crank end portion
  • 35 discharge hole
  • 36 discharge chamber
  • 37 discharge valve
  • 41 gasket
  • 42 gasket
  • 43 bolt
  • 44 inserting hole
  • 45 spring pin
  • 46 insertion hole
  • 47 opening portion
  • 48 cut line
  • 51 solid pin

Claims

1. A motor compressor comprising:

a first housing and a second housing each made of metal, and configured to be insulated from each other by interposing a gasket between mating surfaces, in which facing insertion holes are formed in portions of the mating surfaces where the gasket is not provided; and

an insertion member made of metal, and having one end and the other end which are inserted into the insertion holes, respectively, and an outer peripheral surface which is pressed against inner peripheral surfaces of the insertion holes by an elastic force.

2. The motor compressor according to claim 1, wherein

the insertion member is a spring pin.

3. The motor compressor according to claim 1, wherein

the insertion member is used for positioning in a circumferential direction when fixing the first housing and the second housing.

4. The motor compressor according to claim 1, further comprising:

a third housing made of metal, and configured to be fastened to the first housing by a bolt with the second housing interposed between the first housing and the third housing, and be insulated from the second housing by placing a gasket on a mating surface with the second housing, wherein

the second housing includes an inserting hole having a diameter larger than that of the bolt.

5. The motor compressor according to claim 2, wherein

the insertion member is used for positioning in a circumferential direction when fixing the first housing and the second housing.

6. The motor compressor according to any one of claim 2, further comprising:

a third housing made of metal, and configured to be fastened to the first housing by a bolt with the second housing interposed between the first housing and the third housing, and be insulated from the second housing by placing a gasket on a mating surface with the second housing, wherein

the second housing includes an inserting hole having a diameter larger than that of the bolt.

7. The motor compressor according to claim 3, further comprising:

a third housing made of metal, and configured to be fastened to the first housing by a bolt with the second housing interposed between the first housing and the third housing, and be insulated from the second housing by placing a gasket on a mating surface with the second housing, wherein

the second housing includes an inserting hole having a diameter larger than that of the bolt.

8. The motor compressor according to claim 5, further comprising:

a third housing made of metal, and configured to be fastened to the first housing by a bolt with the second housing interposed between the first housing and the third housing, and be insulated from the second housing by placing a gasket on a mating surface with the second housing, wherein

the second housing includes an inserting hole having a diameter larger than that of the bolt.