JP2011236858A - Earth connection structure of electric compressor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an earth connection structure of an electric compressor to ground a power cable and prevent an increase in the number of parts items while preventing deterioration in work efficiency, with a simple structure.SOLUTION: The electric compressor includes an inverter circuit board 31 mounted in an inverter storage part 32 formed in a housing 2. The power cable 48 connected to the power source input side (primary side) of an inverter driving circuit is constituted of a shield wire. A conductive shielding material 48c covered via an insulator around a conductor of the shielding wire, is grounded by a casing on the housing 2 by fastening with a screw 59 together with the inverter circuit board 31 to a board arranging installation object part arranged in the inverter storage part 32.

Description

  The present invention relates to a ground connection structure for an electric compressor formed by integrally assembling an inverter device on the outer periphery of a housing in which a compression mechanism and an electric motor are built in, and is particularly connected to a power input side of an inverter drive circuit. The present invention relates to a grounding structure of a shielded wire as a power cable.

As a compressor for an air conditioner mounted on a vehicle, an inverter-integrated electric compressor in which an inverter device is integrated is proposed (see Patent Documents 1 and 2, etc.). This inverter-integrated electric compressor is provided with an inverter housing portion on the outer periphery of a housing in which the motor and the compression mechanism are built, and converts DC power supplied from a high-voltage power source into three-phase AC power into the motor. An inverter device for supplying electric power is incorporated, and the rotational speed of the electric motor is variably controlled by this inverter device.
In such an inverter device, an inverter circuit board on which a drive circuit module in which switching elements of the inverter drive circuit are modularized is arranged by screwing or the like at a predetermined position of the inverter housing portion. A power cable for supplying power from an external high voltage power source is connected to the input side (primary side).
Normally, this power cable uses a shielded wire with a braided conductive shield material (braided conductor) made of a conductive coating around the core wire, and the DC power supplied from the high voltage power supply is three-phase AC power. The conductive shield material suppresses the influence of noise that is generated when converting to. For this reason, it is necessary to ground the conductive shield material of the shield wire in order to suppress the influence of the floating voltage. Conventionally, for example, as shown in Patent Document 3, the housing is grounded to the housing (frame Grand).
The configuration shown in Patent Document 3 relates to a connector structure of a power cable using a shielded wire. By attaching the connector to the compressor housing, the shielded wire and the compressor housing are electrically connected simultaneously with the connection of the power cable. It is intended to be connected.

JP 2005-36753 A JP2007-162661 JP2003-239862

However, in the configuration described above, the number of parts of the connector itself is large and the structure is complicated, so that there is a disadvantage that workability at the time of assembling the connector is deteriorated. In addition, a large space is required for the connector mounting portion of the compressor housing, which makes it difficult to reduce the size of the compressor.
The present invention has been made in view of such circumstances, and is an electric compressor capable of grounding a power cable with a simple structure, suppressing an increase in the number of parts, and avoiding deterioration in workability. The main issue is to provide a ground connection structure.

In order to achieve the above object, an earth connection structure for an electric compressor according to the present invention includes a compression mechanism section and an electric motor that drives the compression mechanism section in a housing, and an inverter device that operates the electric motor in the housing. The inverter device is configured by mounting an inverter circuit board on which an inverter drive circuit is mounted in an inverter housing portion formed in the housing, and driving the inverter A power cable connected to the power input side of the circuit is constituted by a shielded wire, and a conductive shield material for covering the periphery of the core wire of the shielded wire through an insulator is used for installing the board provided in the inverter accommodating portion. The housing is grounded to the housing by tightening together with the inverter circuit board with a screw to the mounted part It is characterized.
Therefore, the conductive shield material of the shield wire used as the power cable is fastened together with the inverter circuit board with the screw to the attachment site for fixing the inverter circuit board to the inverter housing portion. There is no need to newly provide a connector mounting portion for grounding, and the existing structure can be used.
Specifically, the shield conductor is twisted into a wire shape to form a shield stranded wire, and a crimp terminal is crimped to the tip, and the crimp terminal is screwed together with the inverter circuit board to the attachment site. It is good to tighten together.
In particular, the inverter housing part is provided outside the housing in which a suction path for guiding the working fluid to the compression mechanism part is formed, and the inverter circuit board is a drive circuit module in which the switching elements of the inverter drive circuit are modularized. In the case where the shield wire is attached in close contact with the installation surface of the partition wall that separates from the suction path of the inverter housing portion, the shield wire is opposite to the surface of the inverter circuit board on which the drive circuit module is attached. It is desirable to be tightened together.
This is because when the shield wire is fastened together on the same side as the surface of the inverter circuit board on which the drive circuit module is mounted, the drive circuit module floats from the installation surface where it is installed by the thickness of the connector to be fastened together. This is because the cooling of the drive circuit module, which has been performed by being brought into close contact with the installation surface, is impaired.
In addition, when the grounding pattern of the inverter drive circuit is applied to the part to be attached to the fixing hole of the inverter circuit board, the grounding of the inverter circuit board should be performed at the same time by co-fastening the part to be attached with the screw. May be.
According to such a configuration, the installation of the inverter circuit board and the grounding of the shield wire can be performed simultaneously with the same screw, and it is not necessary to disperse the installation place. Therefore, it is necessary to increase the accommodation space of the inverter circuit board. In addition, the grounding work becomes easy.

As described above, according to the present invention, the power cable connected to the power input side (primary side) of the inverter drive circuit of the inverter device is constituted by the shield wire, and the conductive wire covering the periphery of the core wire of the shield wire. Since the housing shield is grounded together with the inverter circuit board with screws to the mounting location for fixing the inverter circuit board to the inverter housing part, the power shield cable is grounded with a simple structure. Thus, the increase in the number of parts can be suppressed and installation work can be easily performed. In addition, when grounding the conductive shield material, it is not necessary to prepare a new part, and it is not necessary to newly provide a connector mounting portion for grounding.
In addition, when the inverter circuit board is mounted in close contact with the installation surface of the partition wall that separates the drive circuit module obtained by modularizing the switching element of the inverter drive circuit from the suction path of the inverter housing portion, the shield wire Is fastened to the opposite side of the surface of the inverter circuit board on which the drive circuit module is mounted, the cooling of the drive circuit module is not impaired.
Furthermore, when the grounding pattern of the inverter drive circuit is provided in the fixing hole of the inverter circuit board, the grounding of the shield line of the power cable is performed by simultaneously grounding the inverter circuit board with a screw. And the grounding of the inverter circuit board can be performed simultaneously with the same screw, the grounding work is facilitated, and the grounding places are not dispersed, so that it is not necessary to secure a large accommodation space for the inverter circuit board.

FIG. 1 is a cross-sectional view showing an example of the overall configuration of an electric compressor according to the present invention. FIG. 2 is an exploded perspective view showing each component attached to the inverter accommodating portion of the electric compressor. 3A and 3B are views showing a housing portion that accommodates the electric motor and the inverter of the electric compressor, wherein FIG. 3A is a plan view thereof, and FIG. 3B is a cross-sectional view thereof. 4A and 4B are diagrams showing the inverter circuit board, in which FIG. 4A is a plan view thereof, FIG. 4B is a bottom view thereof, and FIG. 4C is a side view thereof. FIG. 5 is a plan view showing an inverter accommodating portion of a compressor to which an inverter circuit board of the electric compressor is attached, (a) is an overall view thereof, and (b) is an enlarged view showing a periphery of a terminal portion to which a shield wire is attached. It is.

  Embodiments of the present invention will be described below with reference to the accompanying drawings.

  FIG. 1 shows an electric compressor 1 suitable for a refrigeration cycle using a refrigerant as a working fluid. This electric compressor 1 is provided with a compression mechanism 3 on the left side in the figure in a housing 2 made of an aluminum alloy, and an electric motor 4 for driving the compression mechanism on the right side in the figure. Yes. In FIG. 1, the right side in the drawing is the front side of the compressor, and the left side in the drawing is the rear side of the compressor.

  Inside the housing 2, there is provided a drive shaft 8 rotatably supported by bearings 6 and 7 on a block member 5 as a shaft support member fixed in the middle of the housing 2 and a front wall portion 2 a of the housing 2. It has been. The block member 5 defines the inside of the housing 2 into a compression mechanism housing portion 9 a for housing the compression mechanism 3 and an electric motor housing portion 9 b for housing the electric motor 4.

The compression mechanism 3 is a scroll type having a fixed scroll member 10 and a movable scroll member 11, and the fixed scroll member 10 includes a disk-shaped substrate 10 a fixed inside the rear portion of the housing 2, and It is comprised from the spiral fixed spiral wall 10b extended toward the front from this board | substrate 10a.
The movable scroll member 11 is disposed opposite to the front side of the fixed scroll member 10, and includes a disk-shaped substrate 11a and a spiral movable spiral wall erected rearward from the substrate 11a. 11b, and is supported by an eccentric shaft 8a provided at the rear end portion of the drive shaft 8 via a bush 12 and a bearing 13. Reference numeral 19 denotes a balance weight provided at the rear end of the drive shaft 8.

  The fixed scroll member 10 and the movable scroll member 11 are meshed with each other with respective spiral walls 10b and 11b, and the tips of the respective spiral walls 10b and 11b are in contact with the substrates 10a and 11a of the mating scroll member. Therefore, the compression chamber 15 is defined in a space surrounded by the substrate 10 a and the fixed spiral wall 10 b of the fixed scroll member 10 and the substrate 11 a and the movable spiral wall 11 b of the movable scroll member 11.

  Further, the outer peripheral edge of the fixed scroll member 10 and the outer peripheral wall 5 a extending rearward of the block member 5 are put together and positioned by a pin 16, and the outer peripheral wall 11 c extending forward is formed on the outer peripheral edge of the movable scroll member 11. And the annular step portion 5 b formed inside the block member 5 are abutted via a thrust plate 17. Further, an Oldham ring 18 that prevents the movable scroll member 11 from rotating is disposed between the movable scroll member 11 and the block member 5.

  Between the outer peripheral wall 5a of the block member 5 and the outermost peripheral portion of the movable spiral wall 11b of the movable scroll member 11, refrigerant introduced from a suction port 29 (described later) through a suction path 39 is sucked into the compression chamber 15. A suction chamber 20 is formed, and the refrigerant gas compressed in the compression chamber 15 is discharged through a discharge hole 21 formed substantially in the center of the fixed scroll member 10 behind the fixed scroll member 10 in the housing. A discharge chamber 22 is defined between the rear wall 2 b of the housing 2. The refrigerant gas discharged into the discharge chamber 22 is pressure-fed from the discharge port 24 to an external refrigerant circuit (not shown).

  On the other hand, the stator 25 and the rotor 28 which comprise the electric motor 4 are provided in the electric motor accommodating part 9b formed ahead of the block member 5 in the housing 2. The stator 25 is composed of a cylindrical iron core 26 and a coil 27 wound around the iron core 26, and is fixed to the inner surface of the housing 2. The rotor 28 is fixed to the drive shaft 8 and is configured by a magnet rotatably accommodated inside the stator 25, and is rotated by a rotating magnetic force formed by the stator 25. .

  A suction port 29 for sucking refrigerant gas is formed on the side surface of the housing 2 facing the motor housing portion 9b, and a gap between the stator 25 and the housing 2 or between the block member 5 and the housing 2 (not shown). In addition, a suction path 39 that guides the refrigerant that has flowed from the suction port 29 into the electric motor housing portion 9b to the suction chamber 20 through a gap formed between the fixed scroll member 10 and the housing 2 is formed.

  Accordingly, when the electric motor 4 rotates and the drive shaft 8 rotates, the movable scroll member 11 is driven by the eccentric shaft 8 a in the compression mechanism 3, so that the movable scroll member 11 moves around the axis of the fixed scroll member 10. Revolve. At this time, the movable scroll member 11 is prevented from rotating by the rotation preventing mechanism including the Oldham ring 18, so that only the revolving motion is allowed.

  By the revolving motion of the movable scroll member 11, the compression chamber 15 moves while gradually decreasing the volume from the outer peripheral side of the spiral walls 10b, 11b of both scroll members to the center side. The compressed refrigerant gas is compressed, and the compressed refrigerant gas is discharged into the discharge chamber 22 through the discharge hole 21 formed in the substrate 10a of the fixed scroll member 10, and sent to the external refrigerant circuit through the discharge port 24. Is done.

  In such an electric compressor 1, as shown in FIG. 2, an inverter circuit board 31 on which an inverter drive circuit 30 for performing power feeding control of the electric motor 4 is mounted is an outer surface near the front of the housing 2, that is, The motor is housed in an inverter housing portion 32 formed on the upper outer surface of the portion housing the motor 4.

  The inverter accommodating portion 32 is configured by attaching a lid 35 with a screw 36 to an accommodating recess 33 formed on the outer peripheral wall of the housing 2 via an O-ring 34, as shown in FIG. Boss portions (attachment sites) 37 for fixing the inverter circuit board 31 are formed at the four corners of the accommodating recess 33, and fixing holes 38 made of screw holes are formed therein. In addition, an installation surface 41 that abuts a drive circuit module 54 (described later) is provided at a portion desired for the inverter accommodating portion 32 of the partition wall 40 that partitions the inverter accommodating portion 32 of the housing 2 and the electric motor accommodating portion 9b that accommodates the electric motor 4. Is formed.

  As shown in FIG. 4, a connector 43 is integrally connected to the inverter drive circuit 30 via a cable 42, and a connector 45 is also integrally formed to the stator 25 of the electric motor 4 via a cable 44. Has been. The inverter drive circuit 30 connects the connector 43 from above to a terminal (airtight terminal) 46 provided on the partition wall 40 at the rear portion of the inverter accommodating portion 32 of the housing 2, and the stator 25 of the electric motor 4 is connected to the terminal 46. The connector 45 is connected to the partition 40 from below, and the inverter drive circuit 30 and the stator 25 are electrically connected via a terminal 46 to supply a drive current to the motor 4.

  The inverter drive circuit 30 converts DC power supplied from the outside into multiphase AC power and supplies it to the motor 4, and controls the rotational speed of the motor 4 based on a control signal from the outside. The drive circuit module 54 in which the switching elements of the inverter drive circuit 30 are modularized is fixed to the back surface of the inverter circuit board 31, that is, the surface facing the partition wall 40. The drive circuit module 54 has heat generating elements integrated therein, so that the drive circuit module 54 is in close contact with the installation surface 41 formed on the partition wall 40 via grease, and is cooled by the refrigerant flowing through the suction path 39. .

  Further, a control system cable 47 in which a voltage line for supplying an operating voltage for the inverter drive circuit 30 and a control line for inputting a signal relating to the required rotation speed of the motor generated externally, and a power source for driving the motor are provided. The power supply cable 48 to be supplied is introduced into the inverter accommodating portion 32 through the cable insertion holes 49 and 50 formed in the side wall of the housing 2 that defines the inverter accommodating portion 32. A connector 51 provided at the tip is connected to a connector receiver 52 provided on the inverter circuit board 31, and the power cable 48 is connected to a power connection connector 53 provided on the inverter circuit board 31 by a screw 56. Connected.

  The power supply connector 53 provided on the inverter circuit board 31 is provided in the vicinity of the boss part 37 for fixing the inverter circuit board 31 in the inverter housing part 32. In this example, FIG. As shown, the inverter accommodating portion 32 is provided on the side away from the cable insertion hole 50 on the rear end side.

  The power cable 48 is composed of two direct-current shielded wires 48a and 48b. Each shield wire 48a, 48b covers the periphery of the core wire for supplying power with a conductive shield material 48c made of a braided conductor via an insulation jacket (insulator), and further surrounds the periphery thereof with an insulation jacket (insulator). The shield wire 48a that constitutes the positive pole and the shield wire 48b that constitutes the negative pole are formed by twisting each conductive shield material 48c in the shape of an electric wire into one branch. A line is formed. Crimp terminals 55a, 55b, and 55c are crimped and connected to the cores of the respective shield wires 48a and 48b and the tip of the conductive shield material 48c as a branch line.

  The crimp terminals 55a and 55b connected to the core wire are fastened to the power connection connector 53 by screws 56, and the crimp terminal 55c connected to the conductive shield material 48c is connected to the inverter circuit board 31. Together with the inverter circuit board 31, the screw 59 is fixed together with the fixing hole 38 of the boss portion 37.

  The inverter circuit board 31 is formed with screw insertion holes 57 through which the screws 59 are inserted at the four corners, and the periphery of the screw insertion hole 57 for attaching the crimp terminal 55c of the conductive shield material (branch line) 48c of the power cable 48. The ground pattern 58 of the inverter drive circuit 30 is applied. For this reason, the crimp terminal 55c provided at the tip of the conductive shield material (branch line) 48c is disposed on the periphery of the screw insertion hole 57 so as to cover the ground pattern 58 from above the inverter circuit board 31, and this crimp terminal. The ground pattern 58 is pressed by a screw 59 that is screwed into the fixing hole 38 of the boss portion 37 through 55 c and the screw insertion hole 57.

  Therefore, the ground pattern 58 of the inverter circuit board 31 is electrically connected to the housing 2 via the boss portion 37 by the screw 59, and the conductive shield material (branch line) 48 c of the power cable 48 is also connected to the boss portion by the screw 59. The inverter circuit board 31 and the conductive shield material 48 c of the power cable 48 are both grounded by the same screw 59.

  Therefore, according to the above-described configuration, the conductive shield material 48c of the shield wires 48a and 48b constituting the power cable 48 is fastened together with the inverter circuit board 31 by the screw 59 for attaching the inverter circuit board 31, so that the inverter Simultaneously with the mounting of the circuit board 31, the conductive shield material 48c can be grounded, and the mounting work can be simplified. Further, since it is not necessary to provide a special grounding location for grounding the conductive shield material 48c of the power cable 48, the structure of the inverter housing portion 32 can be simplified and the inverter housing portion 32 can be reduced in size. Become.

  Further, in the above-described configuration, the grounding of the inverter circuit board 31 is simultaneously performed by the screw 59 used for grounding the conductive shield material 48c. It is possible to reduce the size of the storage space and simplify the grounding work.

  Furthermore, in the above-described configuration, the drive circuit module 54 of the inverter circuit board 31 is provided with the crimp terminal 55c provided at the tip of the conductive shield material 48c for grounding the shield wires 48a and 48b of the power cable 48. Since it is screwed together with the inverter circuit board 31 on the opposite side (the boss portion 37, the inverter circuit board 31, the crimp terminal 55c, and the screw 59 are arranged in this order), the partition wall of the inverter circuit board 31 The distance from 40, that is, the distance from the installation surface 41 of the drive circuit module 54 is not changed by co-fastening the conductive shield material 48 c with the inverter circuit board 31, and the drive circuit module 54 is removed from the installation surface 41. This eliminates the inconvenience of being difficult to cool away.

DESCRIPTION OF SYMBOLS 1 Electric compressor 2 Housing 4 Electric motor 30 Inverter drive circuit 31 Inverter circuit board 32 Inverter accommodating part 38 Screw hole 41 Installation surface 48 Power cable 48c Conductive shield material 54 Drive circuit module 55c Crimp terminal 58 Grounding pattern 59 Screw

Claims (4)

A grounding structure for an electric compressor comprising a compression mechanism section and an electric motor for driving the compression mechanism section in a housing, and an inverter device for operating the electric motor in the housing.
The inverter device is configured by mounting an inverter circuit board on which an inverter drive circuit is mounted in an inverter accommodating portion formed in the housing, and a power cable connected to a power input side of the inverter drive circuit is shielded. The conductive shield material that covers the periphery of the core wire of the shield wire via an insulator is tightened together with the inverter circuit board with a screw with respect to the installation site for the board installation provided in the inverter housing portion. A ground connection structure for an electric compressor, wherein the housing is grounded to the housing.   The conductive shield material is twisted into a wire shape to form a shield stranded wire, and a crimp terminal is crimped and connected to the distal end of the conductive shield material. The ground connection structure for an electric compressor according to claim 1, wherein the ground connection structure is tightened.   The inverter housing part is provided outside a housing in which a suction path for guiding the working fluid to the compression mechanism part is formed, and the inverter circuit board is a drive circuit module in which switching elements of the inverter drive circuit are modularized Is attached in close contact with the installation surface of the partition wall that separates the suction path of the inverter housing portion, and the shield wire is on the opposite side to the surface of the inverter circuit board on which the drive circuit module is attached. The ground connection structure for an electric compressor according to claim 1, wherein the ground connection structure is tightened.   A portion of the inverter circuit board that is attached to the attached portion is provided with a grounding pattern of the inverter drive circuit, and the inverter circuit substrate is grounded simultaneously by being fastened to the attached portion with the screw. The ground connection structure for an electric compressor according to any one of claims 1 to 3.

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