CN111480003B

CN111480003B - Electric compressor

Info

Publication number: CN111480003B
Application number: CN201880081164.8A
Authority: CN
Inventors: 高部哲也
Original assignee: Sanden Automotive Conponents Corp
Current assignee: Sanden Corp
Priority date: 2017-12-22
Filing date: 2018-11-12
Publication date: 2022-06-24
Anticipated expiration: 2038-11-12
Also published as: WO2019123929A1; DE112018006520T5; CN111480003A; JP7153169B2; JP2019112987A

Abstract

In a split type casing of an electric compressor, the casings can be electrically connected with each other with or without a gasket interposed therebetween, and an equipotential between the casings can be secured. The gasket (16) sandwiched between the housings is configured to include a metal base material and a rubber layer covering both surfaces of the metal base material. The gasket (16) is annular and has annular beads (101, 102) on the inner edge side and the outer edge side, respectively. An electrical connection portion (metal base material exposed portion) (109) is provided between the ribs (101, 102) on both sides, the electrical connection portion being formed by removing a part of the rubber layer to expose the metal base material. A metal base material exposure portion (109) on the convex surface (105) side is provided at the edge portion of the bolt through hole (107).

Description

Electric compressor

Technical Field

The present invention relates to an electric compressor in which an electric motor and a compression mechanism are housed in a housing, and more particularly to an electric compressor of a type in which the housing is divided into a plurality of parts in an axial direction of the electric motor and joined to each other with a gasket interposed therebetween.

Background

As an electric compressor, an inverter-integrated electric compressor described in patent document 1 is known.

The electric compressor includes: a casing (main body case) that houses the electric motor and the compression mechanism; an inverter case having an opening at one end, the inverter case accommodating an inverter for driving an electric motor; and a cover-shaped inverter cover that closes the opening of the inverter case. They are all made of metal.

Here, the inverter case and the inverter cover are joined to each other by sandwiching a gasket as a seal between annular joining surfaces of the inverter case and the inverter cover. However, the gasket has insulation due to the rubber layer on the surface. Thus, it is necessary to electrically connect the inverter case and the inverter cover. Therefore, a convex portion as an electrical connection portion is provided on one of the annular joint surfaces at a position inside the gasket, and the convex portion and the gasket are brought into direct contact with each other.

Documents of the prior art

Patent document

Patent document 1: japanese patent laid-open No. 2015-017577

Disclosure of Invention

Technical problem to be solved by the invention

However, as a frame structure of the electric compressor, there are frame structures of the following types: a housing that houses an electric motor and a compression mechanism is divided into a first housing that houses the electric motor and a second housing that houses the compression mechanism, and the first housing and the second housing are joined to each other with a gasket interposed therebetween.

In the case of the electric compressor having the frame structure of the above type, a potential difference may be generated between the first casing and the second casing, and at the place of delivery of the product, a sense of discomfort may be brought about due to a current flowing through the first casing and the second casing due to contact with them by a person.

Therefore, the first enclosure and the second enclosure are required to be equipotential.

As a countermeasure for the equipotentialization, it is conceivable to provide a convex portion as an electrical connection portion on the annular joint surface of the first casing or the second casing at a position inside the gasket, as in the case of the countermeasure in patent document 1.

However, when the width of the annular joint surface (the thickness of the housing) cannot be set large, the measure of patent document 1 is difficult.

In the case of the inverter case and the inverter cover, it is also conceivable to provide a protruding portion rising from the inner bottom portion of the inverter case and to bring the tip of the protruding portion into contact with the inner surface of the inverter cover to electrically connect the inverter case and the inverter cover (see japanese patent application No. 2017 and 109158 of the present applicant).

However, since the first housing has an electric motor therein and the second housing has a compression mechanism therein, it is difficult to provide an electrical connection portion in the housing.

In view of the above circumstances, an object of the present invention is to equalize the electric potential between a first casing that houses an electric motor and a second casing that houses a compression mechanism with a relatively simple configuration.

Technical scheme for solving technical problem

The motor-driven compressor of the present invention includes: a first metal housing that houses the electric motor; a second housing that houses a compression mechanism driven by the electric motor; and an annular gasket interposed between the annular joint surface of the first housing and the annular joint surface of the second housing. Furthermore, it is characterized in that the gasket has an electrical connection portion that enables electrical connection of the first housing and the second housing.

Preferably, the gasket includes a metal base and rubber layers covering both surfaces of the metal base, and the electrical connection portions are metal base exposed portions formed on both surfaces of the gasket and exposing the metal base by removing a part of the rubber layers.

Further, it is preferable that the gasket has annular beads on an inner edge side and an outer edge side thereof, respectively, and has through holes for bolts for fastening the first case and the second case between the beads, and the metal base material exposed portion is formed between the beads.

Effects of the invention

According to the present invention, by providing the electrically connecting portion in the gasket itself (a part in the circumferential direction and a part in the width direction), the electrically connecting portion can be implemented without increasing the width of the joint surface, and the first case and the second case can be made equipotential.

In particular, the gasket can be very easily provided with the metal base material exposed portion. Further, since the rib is provided between the ribs, the influence on the sealing performance can be avoided.

Drawings

Fig. 1 is a longitudinal sectional view showing an electric compressor according to an embodiment of the present invention.

Fig. 2 is a front view of the gasket corresponding to the view from a-a in fig. 1.

Fig. 3 is a rear view of the above-described gasket.

Fig. 4 is an enlarged view of a portion B of fig. 2.

Fig. 5 is a cross-sectional view C-C of fig. 4.

Fig. 6 is a cross-sectional view taken along line D-D of fig. 4.

Detailed Description

Hereinafter, embodiments of the present invention will be described in detail.

Fig. 1 is a longitudinal sectional view showing an electric compressor according to an embodiment of the present invention. The electric compressor of the present embodiment is of a horizontal type (compression center axis is horizontal), and is incorporated into a refrigerant circuit of a vehicle air conditioner, and sucks and compresses a refrigerant and discharges the refrigerant. Lubricating oil is mixed into the refrigerant.

The motor-driven compressor 1 has a casing divided into a plurality of parts in the compressor center axis direction, and includes a front casing (first casing) 2, an intermediate casing (second casing) 3, and a rear casing (third casing) 4. They are fastened together in a manner described later.

The front housing 2 is substantially cylindrical and has a partition wall 5 in the middle in the axial direction. An electric motor housing space is formed on the right side in the drawing of the partition wall 5 of the front housing 2, in which the electric motor 6 is housed.

The electric motor 6 includes: a rotating shaft 6a, the rotating shaft 6a being rotatably supported at a center portion in the front housing 2; a rotor 6b with a permanent magnet, the rotor 6b being installed around the rotation shaft 6 a; and a stator 6c having an electromagnetic coil, the stator 6c being fixed to and held by an inner wall of the front case 2, and surrounding the rotor 6 b.

An inverter housing space is formed on the left side of the partition wall 5 of the front housing 2 in the drawing, and an inverter (drive circuit for an electric motor) 7 is housed therein.

The inverter 7 controls power supply to the electric motor 6 while converting a direct current from an external power supply into an alternating current.

In more detail, the inverter 7 includes: a capacitor that smoothes a direct-current voltage from an external power supply; a power module that converts the dc voltage from the capacitor into an ac voltage by PWM control (control for generating a voltage obtained by modulating a pulse width in a certain period in order to obtain a sine wave by simulation), and supplies the ac voltage to a coil on the stator 6c side of the electric motor 6; and a power module control circuit that controls the power module so as to drive the electric motor 6 based on a control signal from an external air conditioning control device.

An opening of the inverter housing space of the front case 2 (in other words, an opening of the inverter case) is closed by a lid-shaped inverter cover 8.

The intermediate housing 3 is substantially cylindrical, and accommodates a compression mechanism 9 driven by the electric motor 6 therein.

The compression mechanism 9 of the present embodiment is a scroll-type compression mechanism, and includes a fixed scroll member 10, an orbiting scroll member 11, and a crank mechanism portion 12.

Fixed scroll member 10 and orbiting scroll member 11 are arranged opposite to each other in the central axis direction so that

scroll wraps

10b and 11b are integrally formed on

end plates

10a and 11a, respectively.

Orbiting scroll member 11 is made to orbit on a circular orbit around the central axis of the compressor by a rotating shaft 6a of electric motor 6 via a crank mechanism 12, and is prevented from rotating.

As a result, the fluid groove formed between the scroll lap 10b of the fixed scroll member 10 and the scroll lap 11b of the orbiting scroll member 11 is moved while the volume thereof is decreased from the outer peripheral side to the inner peripheral side, and the fluid (i.e., refrigerant gas) sucked into the fluid groove on the outer peripheral side is compressed.

A refrigerant suction port (not shown) is provided in an outer wall of the front casing 2 or the intermediate casing 3. The refrigerant sucked from the suction port flows through the front housing 2, lubricates and cools the electric motor 6 (and cools the inverter 7 via the partition wall 5), then flows through the intermediate housing 3, and is sucked into the fluid groove from the outer peripheral side of the

scroll wraps

10b and 11b to be compressed.

The compressed refrigerant is discharged from discharge hole 13 with a check valve provided at the center of end plate 10a of fixed scroll member 10.

Rear housing 4 is disposed in a cover shape with respect to intermediate housing 3, and forms a refrigerant discharge chamber 14 with an end plate 10a of fixed scroll member 10 fixed to intermediate housing 3.

Therefore, the refrigerant compressed by the compression mechanism 9 is discharged from the discharge hole 13 into the discharge chamber 14 in the rear housing 4, and is led out therefrom to the outside through the discharge port 15 provided in the outer wall of the rear housing 4.

Next, a fastening structure and a sealing structure of the front casing 2, the middle casing 3, and the rear casing 4 will be described.

An annular gasket 16 is interposed between the joining surface on the outer peripheral side of the front housing 2 and the joining surface on the outer peripheral side of the intermediate housing 3, so that the front housing 2 and the intermediate housing 3 are joined. Similarly, the intermediate case 3 (and the end plate 10a) and the rear case 4 are joined to each other by sandwiching an annular gasket 17 between the joining surface on the outer peripheral side of the intermediate case 3 (and the end plate 10a) and the joining surface on the outer peripheral side of the rear case 4.

As will be described in detail later, the gaskets 16 and 17 are provided with rubber layers on both surfaces of a metal base material, and have insulation properties with respect to members to be joined.

Next, the front casing 2, the middle casing 3, and the rear casing 4 are fastened by a plurality of (for example, six) bolts 18 arranged at appropriate intervals along their circumferential directions.

Each bolt 18 penetrates the rear casing 4 and the intermediate casing 3 from the rear casing 4 side in parallel with the compressor center axis, and is screwed to the front casing 2.

Thus, bolt through holes are formed in the rear case 4 and the intermediate case 3. The washers 17 and 16 are also formed with bolt through holes. Further, screw holes 2s into which the bolts 18 are screwed are formed in the front housing 2.

The seat surface of the head portion of the bolt 18 is fixed to the rear case 4, the shaft portion passes through the bolt through holes of the rear case 4, the washer 17, the intermediate case 3, and the washer 16, and the screw portion at the front end is screwed into the screw hole 2s of the front case 2.

Therefore, the front housing 2 and the rear housing 4 are not in direct contact with each other, but are electrically connected via the bolts 18. This is because the head portion of the bolt 18 contacts the rear housing 4 with sufficient contact pressure, and the threaded portion of the bolt 18 contacts the threaded hole 2s of the front housing 2 with sufficient contact pressure.

In contrast, the front housing 2 and the middle housing 3 are not electrically connected. This is because the bolts 18 are loosely fitted into the bolt insertion holes of the intermediate housing 3 only with play, and are not in direct contact with the insulating washer 16 interposed therebetween.

Therefore, in the present embodiment, a countermeasure for equalizing the potential of the gasket 16 between the front case 2 and the intermediate case 3 is taken.

The detailed structure of the gasket 16 and the countermeasure for equipotentialization will be described with reference to fig. 2 to 6.

Fig. 2 is a front view of the gasket 16 corresponding to a view from a-a in fig. 1, fig. 3 is a rear view of the gasket 16, fig. 4 is an enlarged view of a portion B in fig. 2, fig. 5 is a sectional view from C-C in fig. 4, and fig. 6 is a sectional view from D-D in fig. 4.

The gasket 16 is formed by punching a metal plate coated with a rubber layer into a ring shape and processing a rib simultaneously with or before and after the punching.

Therefore, as shown in fig. 5 (and fig. 6), the gasket 16 includes a metal base 16a and a rubber layer 16b covering both surfaces of the metal base 16 a. The thickness of the metal base material 16a is about 0.2mm, and the thickness of the rubber layers 16b on both sides is about 0.1 mm.

The gasket 16 has annular beads (japanese: ビード) (half beads (japanese: ハーフビード))101 and 102 on the inner edge side and the outer edge side, respectively.

The inner side of the rib 101 on the inner edge side and the outer side of the rib 102 on the outer edge side serve as seat surfaces (reference surfaces) 103 and 104.

Further, the rib 101 on the inner edge side and the rib 102 on the outer edge side have a convex surface (convex flat surface) 105 therebetween when viewed from the front side, and have a concave surface (concave flat surface) 106 when viewed from the rear side.

In addition, when the front housing 2, the intermediate housing 3, and the rear housing 4 are assembled, the front housing 2 is generally disposed with the joining surface facing upward with respect to a jig, and the gasket 16, the intermediate housing 3, the gasket 17, and the rear housing 4 are placed thereon in this order. Thus, the gasket 16 faces the seat surface downward to be stable.

In this case, the seating surfaces 103 and 104 (and the concave surface 106) of the gasket 16 are on the front housing 2 side, and the convex surface 105 of the gasket 16 is on the middle housing 3 side.

Furthermore, the washer 16 has, for example, six bolt through holes 107 and two positioning holes 108 between the inner edge-side rib 101 and the outer edge-side rib 102.

The bolt through holes 107 are through holes of bolts 18 that fasten the rear housing 4, the intermediate housing 3, and the front housing 2 as already described.

The positioning hole 108 is a hole for positioning when the gasket 16 is provided on the front housing 2 at the time of the assembly. For the positioning, a positioning pin 19 (see fig. 1) is provided so as to protrude from a joint surface on the front housing 2 side. Further, a guide hole 20 (see fig. 1) is formed in a joint surface of the intermediate housing 3, and the guide pin 19 is fitted into the guide hole 20.

The shape and structure of the gasket 16 and the gasket 17 described above are also the same.

The gasket 16 for the countermeasure against the equipotentialization has the following shape and structure as a specific shape and structure.

Between the inner edge-side bead 101 and the outer edge-side bead 102 of the washer 16, an electrical connection portion 109 is formed on the convex surface 105 side so as to be positioned at an edge portion of any of the bolt through holes 107 (see fig. 2, 4, and 6).

The electrical connection portion 109 is a metal base exposed portion obtained by removing (for example, cutting) the rubber layer at the above-described portion to expose the metal base.

Between the bead 101 on the inner edge side and the bead 102 on the outer edge side of the gasket 16, a convex portion 110 (see fig. 3 and 6) protruding in a circular shape is formed on the concave surface 106 side. The convex portion 110 is a convex portion when viewed from the back side, and is a concave portion 110' when viewed from the front side.

Further, an electrical connection portion 111 is formed between the bead 101 on the inner edge side and the bead 102 on the outer edge side of the gasket 16 at an edge portion of the circular convex portion 110 on the concave surface 106 side (see fig. 3 and 6).

The electrical connection portion 111 is a metal base exposed portion in which the rubber layer at the above-described portion is removed (e.g., cut) to expose the metal base.

The convex portion 110 is provided in proximity to the bolt through hole 107 forming the electrical connection portion 109. For example, the distance in the circumferential direction between the bolt through hole 107 forming the electrical connection portion 109 and the convex portion 110 is shorter than the distance in the circumferential direction between the other bolt through holes 107 and the convex portion 110. Thus, the electrical connection portion (metal base material exposed portion) 109 on one surface of the gasket 16 and the electrical connection portion (metal base material exposed portion) 111 on the other surface are close to each other in the circumferential direction of the gasket 16.

By using the gasket 16 having the above-described structure, the following effects can be obtained.

The gasket 16 crushes the corner portions of the

ribs

101, 102 between the front and middle casings 2, 3 by fastening the front and middle casings 2, 3. This ensures sealing between the joint surfaces of the front housing 2 and the intermediate housing 3.

Therefore, the sealing between the joint surfaces of the front housing 2 and the intermediate housing 3 is performed by generating a surface pressure at the corner portions of the

beads

101 and 102 of the gasket 16, and therefore, the sealing between the inner edge bead 101 and the outer edge bead 102 is not affected.

Therefore, the rubber layer of a part (109) of one surface between the bead 101 on the inner edge side and the bead 102 on the outer edge side is removed to expose the metal base material, and the rubber layer of a part (111) of the other surface is removed to expose the metal base material.

Since the gasket 16 is compressed by the axial force by providing the metal base material exposed

portions

109 and 111 on both surfaces in the above manner, the front case 2 and the middle case 3 are in metal contact via the metal base material exposed

portions

109 and 111, and equipotential properties can be ensured.

Here, a metal base material exposed portion 109 is provided at an edge portion of the bolt insertion hole 107 on the convex surface 105 side between the

beads

101, 102 of the washer 16. Since the axial force of the bolt 18 reliably acts to increase the surface pressure of the portion, the gasket is easily crushed and the contact pressure is high. This enables reliable electrical connection.

Further, a convex portion 110 is provided on the concave surface 106 side between the

beads

101, 102 of the gasket 16, and a metal base material exposed portion 111 is provided at an edge portion of the convex portion 110. This can increase the surface pressure of the portion to ensure contact pressure, and can reliably achieve electrical connection.

Further, the metal base material exposed

portions

109 and 111 on both sides are slightly distant in the circumferential direction but close in the circumferential direction, and therefore, the front housing 2 and the intermediate housing 3 can be connected with a relatively short distance therebetween via the metal base material 16a, and the electrical connection therebetween is not impaired.

According to the present embodiment, since the gasket 16 has the electrical connection portion that can electrically connect the first case and the second case (the front case 2 and the intermediate case 3), equipotentialization of the first case and the second case can be achieved without increasing the width of the joint portion.

Further, according to the present embodiment, the gasket 16 includes the metal base 16a and the rubber layers 16b covering both surfaces of the metal base 16a, and the electric connection portions are the metal base exposed

portions

109 and 111 which are formed on both surfaces of the gasket 16 and which expose the metal base 16a by removing a part of the rubber layer 16 b. Therefore, the present invention can be easily implemented using an existing gasket.

Further, according to the present embodiment, the washer 16 has

annular beads

101, 102 on the inner edge side and the outer edge side thereof, respectively, and has the through hole 107 for the bolt 18 between the

beads

101, 102, and the metal base material exposed

portions

109, 111 are formed between the

beads

101, 102. Thus, the influence on the sealing performance can be avoided.

In addition, according to the present embodiment, the convex surface 105 is formed between the

beads

101 and 102 on one surface of the gasket 16, the concave surface 106 is formed between the

beads

101 and 102 on the other surface, and the metal base material exposed portion 109 on one surface of the gasket 16 is formed at the edge portion of the through hole 107 of the convex surface 105. Since the fastening axial force near the through hole 107 is large and the contact pressure is large, the electrical connection can be reliably achieved.

Further, according to the present embodiment, the gasket 16 has the convex portion 110 protruding from the concave surface 106, and the metal base material exposed portion 111 on the other surface of the gasket 16 is formed on the convex portion 110. This increases the contact pressure on the concave surface 106 side, and thus the electrical connection can be reliably achieved.

Further, according to the present embodiment, the metal base material exposed portion 109 on one surface and the metal base material exposed portion 111 on the other surface of the gasket 16 are adjacent to each other in the circumferential direction of the gasket 16. This can shorten the connection distance when electrically connecting the metal base material 16 a.

Referring back to fig. 1, a countermeasure for equalizing the potential between the inverter case portion of the front case 2 and the inverter cover 8 will be described.

The inverter housing portion of the front case 2 and the inverter cover 8 are joined and fixed to each other via an insulating gasket 21.

Here, a protruding portion 22 standing from the bottom portion in the inverter case of the front case 2 is provided, and the tip of the protruding portion 22 is brought into contact with the inner surface of the inverter cover 8, whereby electrical connection can be performed. In the above case, the inverter cover 8 is slightly deformed.

In the above description, the electrical connection portion is provided only at the gasket 16 between the first housing (front housing 2) and the second housing (intermediate housing 3), but the same electrical connection portion may be provided at the gasket 17 between the second housing (intermediate housing 3) and the third housing (rear housing 4).

It is needless to say that the illustrated embodiments are merely examples of the present invention, and the present invention includes various improvements and changes by those skilled in the art within the claims, in addition to the cases where the embodiments described are directly shown.

For example, although the above description has been made by processing an existing gasket, a gasket having an electrical connection portion may be newly manufactured.

(symbol description)

1 an electric compressor;

2 a front case (first case);

2s threaded hole;

3 an intermediate case (second case);

4 rear case (third case);

5 a partition wall;

6 an electric motor;

6a rotating shaft;

6b a rotor;

6c a stator;

7 an inverter;

8 inverter cover;

9 a compression mechanism;

10 fixed scroll members;

10a end plate;

10b a scroll wrap;

11 an orbiting scroll member;

11a end plate;

11b a scroll wrap;

12 a crank mechanism portion;

13 discharge holes;

14 a discharge chamber;

15 a discharge port;

16 washers;

16a metal substrate;

16b a rubber layer;

17 a gasket;

18 bolts;

19 positioning pins;

20 guide holes;

21 a gasket;

22 a protrusion from the bottom inside the inverter case;

101. 102 ribs;

103. 104 seat surfaces (reference surfaces);

105 convex (convex flat);

106 concave (concave plane);

107 bolt through holes;

108 positioning holes;

109 an electrical connection portion (metal base material exposure portion);

a 110 convex part;

111 electrical connection portions (metal base material exposure portions).

Claims

1. An electric compressor comprising:

a first metal housing that houses the electric motor; a second housing that houses a compression mechanism driven by the electric motor; and an annular gasket interposed between the annular joint surface of the first housing and the annular joint surface of the second housing,

it is characterized in that the preparation method is characterized in that,

the gasket has an electrical connection portion capable of achieving electrical connection of the first housing and the second housing,

the gasket is constituted to include a metal base material and a rubber layer covering both faces of the metal base material,

the electric connection parts are metal base material exposure parts which are respectively formed on two surfaces of the gasket and are formed by removing part of the rubber layer to expose the metal base material,

the washer has annular beads on an inner edge side and an outer edge side thereof, respectively, and has through-holes of bolts that fasten the first housing and the second housing between the beads,

the metal base material exposed portion is formed between the ribs,

convex surfaces are arranged among the ribs on one surface of the gasket, concave surfaces are arranged among the ribs on the other surface of the gasket,

the metal base material exposed portion of one surface of the gasket is formed at an edge portion of the through hole of the convex surface,

the gasket has a convex portion circularly protruding from a concave surface between the bead on the inner edge side and the bead on the outer edge side,

the metal base material exposed portion of the other surface of the gasket is formed at an edge portion of the convex portion,

the convex portion is provided in proximity to the through hole forming the electrical connection portion so that the metal base material exposed portion of one surface of the gasket and the metal base material exposed portion of the other surface are in proximity in the circumferential direction of the gasket.