JP2003328944A - Electric compressor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electric compressor preventing radiation of electromagnetic noise from a power supply line for supplying DC power from a direct voltage source to an inverter circuit in a housing. <P>SOLUTION: A shield line 7 including two cores 7d and a shield portion 7b covering these cores in a non-contact state is used as a power supply line for supplying the DC power from a battery 8 to the inverter circuit 4 in the housing 9. Each of the cores 7d of the shield line 7 is electrically connected to two power source input terminals 15 of the inverter circuit 4, and the shield portion 7b is electrically connected to the housing 9. Therefore, even if the electromagnetic noise generated in the inverter circuit 4 is superimposed on the cores 7d, the radiation of the electromagnetic noise to the outside is prevented by the shield portion 7b. Further, since the shield portion 7b is electrically connected to the housing 9 to have the same potential as the potential of the housing 9, the radiation of the noise is effectively suppressed. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric compressor used in a vehicle air conditioner, and more particularly to an electric compressor having an inverter circuit housed in a housing.

[0002]

2. Description of the Related Art An electric compressor which operates using a DC power source such as a battery contains a brushless motor (brushless DC motor) for driving a compression mechanism in a metal housing. This brushless motor is driven by a pulse train-shaped pseudo AC voltage converted by an inverter circuit, and its rotation speed is changed by changing the duty ratio of the pseudo AC voltage based on a rotation speed command, thereby changing the effective supply voltage, that is, It is controlled by PWM (pulse width modulation).

Since the inverter circuit converts a DC voltage into a pulse train-like pseudo AC voltage having a predetermined duty ratio by driving the semiconductor switching element ON / OFF, the inverter circuit is installed outside the electric compressor. Then, the electromagnetic noise generated in the inverter circuit and the electromagnetic noise generated in the power supply line between the inverter circuit and the brushless motor are radiated to the outside, and this radiated noise causes the electronic devices mounted on the vehicle to malfunction. Or, there was a problem such as noise being mixed in the output sound of the audio device.

Therefore, recently, in order to prevent the electromagnetic noise generated in the inverter circuit and the electromagnetic noise generated in the power supply line between the inverter circuit and the brushless motor from being emitted to the outside, A metal housing in which an inverter circuit is housed is used as the electric compressor.

[0005]

However, even in the electric compressor in which the inverter circuit is housed in the metal housing, the power supply line for supplying DC power from the DC power supply to the inverter circuit in the housing is exposed to the outside. Therefore, when electromagnetic noise generated in the inverter circuit is superposed on this power supply line, this electromagnetic noise is radiated to the outside from the power supply line, causing a problem similar to the above.

The present invention has been made in view of the above circumstances. An object of the present invention is to radiate electromagnetic noise from a power supply line that supplies DC power from a DC power supply to an inverter circuit in a housing. It is to provide an electric compressor that can be prevented.

[0007]

To achieve the above object, the present invention provides a motor for driving a compression mechanism, and an inverter circuit for converting a DC voltage into a pulse train-like pseudo AC voltage and supplying the pseudo AC voltage to the motor. In an electric compressor housed in a metal housing, a shield provided with two core wires and a shield part for covering them in a non-contact state as a power supply line for supplying DC power from a DC power supply to an inverter circuit in the housing. A wire is used to electrically connect the two core wires of the shield wire to the two power input terminals of the inverter circuit, and the shield portion is electrically connected to the housing.

According to this electric compressor, even if electromagnetic noise generated in the inverter circuit is superimposed on each core wire, the electromagnetic noise can be prevented from being radiated to the outside by the shield portion. Moreover, since the shield portion is electrically connected to the housing so as to have the same electric potential as the housing, the noise radiation can be effectively suppressed.

The above and other objects, constitutional features, and operational effects of the present invention will be apparent from the following description and the accompanying drawings.

[0010]

1 to 4 show an embodiment of the present invention. FIG. 1 is a block diagram of a drive control system including an electric compressor, a power supply line and a battery, and FIG. 3 is a side view of the electric compressor shown in FIG. 3, FIG. 3 is a partially cutaway side view of the electric compressor shown in FIG. 2, and FIG. 4 is an AA line enlarged sectional view and a BB line enlarged sectional view of FIG. Is.

In FIG. 1, reference numeral 1 is an electric compressor used in a vehicle air conditioner, 2 is a compression mechanism including a scroll compression mechanism, and 3 is a three-phase winding type brushless DC motor (hereinafter simply referred to as a brushless motor). Reference numeral 4 is an inverter circuit, 5 is a control circuit, 6 is a capacitor, 7 is a shield wire for power supply, and 8 is a battery mounted on the vehicle.

The electric compressor 1 has a metal housing 9 as shown in FIG. The housing 9 is composed of three parts 9a to 9c connected by bolts and the like, and the compression mechanism 2 is built in the part 9a, and the part 9b.
Includes a brushless motor 3 for driving the compression mechanism 2, and a portion 9c includes an inverter circuit 4 and a control circuit 5.

The electric compressor 1 has a suction port 10 and a discharge port 11 in the housing 9, and the refrigerant used in the vehicle air conditioner is sent from the suction port 10 to the compression mechanism 2 through the brushless motor 3. Then, after being compressed by the operation of the compression mechanism 2, it is delivered from the discharge port 11.

The inverter circuit 4 includes a total of six semiconductor switching elements. By driving these semiconductor switching elements on and off based on the PWM signal from the control circuit 5, a pulse train having a predetermined duty ratio for the DC voltage is provided. It is converted into a pseudo AC voltage and supplied to the brushless motor 3.

The control circuit 5 has a microcomputer configuration and stores a duty ratio calculation program for controlling the speed according to the air conditioning load in the ROM. The control circuit 5 calculates a duty ratio suitable for the rotation speed command from an air conditioning controller (not shown) and sends a PWM signal corresponding to the duty ratio to the inverter circuit 4.

The shield wire 7 is for supplying DC power from the battery 8 to the inverter circuit 4 in the housing 9 (9c). As shown in FIGS. 3 and 4, the shielded wire 7 includes a surface coating 7a, a net-cylindrical shield portion 7b provided inside the surface coating 7a, and a shielded wire 2 provided inside thereof.
It is provided with one covering portion 7c and a core wire 7d provided at the center of each covering portion 7c. As shown in FIG. 1, two core wires 7d
Is connected to the positive electrode and the negative electrode of the battery 8, and the other ends of both are connected to the inverter circuit 4 via the capacitor 6. The capacitor 6 is for the purpose of smoothing the power supply and absorbing the regenerative current from the brushless motor 3.

Here, FIG. 3, FIG. 4 (A) and FIG. 4 (B)
The connection structure between the shielded wire 7 and the inverter circuit 4 will be described with reference to FIG.

The housing 9 integrally has a support portion 12 on the outer surface of the portion 9b, and the support portion 12 has a bolt 1
4, the metal wire cover 13 is detachably attached.

The supporting portion 12 has a sandwiching protrusion 12a at the center, flat portions 12b on both sides thereof, and female screw holes 12c in each flat portion 12b. On the other hand, the cover 13 has a groove portion 13a that allows the holding projection 12a to be inserted in the center of the left side portion in FIG. 3, and has flange portions 13b on both sides thereof that can contact the flat portion 12b. The portion 13b has a bolt insertion hole 13c. The portion of the cover 13 excluding the groove portion 13a and the flange portion 13b has a case-like shape with a vertical cross section having the same height dimension as the groove portion 13a and the same horizontal dimension as both the flange portions 13b.

Also, the cover 1 of the portion 9c of the housing 9
Two power supply input terminals 15 made of copper, which communicate with the inverter circuit 4 in the housing 9, are provided in a portion covered with 3. The holes (not shown) formed in the two power input terminals 15 have two terminal rods 6 a of the capacitor 6.
Holes (not shown) formed in the L-shaped relay terminal 16 made of copper in the protruding portions of the respective terminal rods 6a.
Are fitted together, and the nuts 17 are fastened to the projecting portions of the respective terminal rods 6a, so that the two power input terminals 15
A capacitor 6 and a relay terminal 16 are connected to the.

When connecting the shielded wire 7 to the electric compressor 1, first, the surface coating 7a of the shielded wire 7 is partially removed to expose the shield portion 7b, and the two coating portions 7c are partially removed. The core wire 7d is exposed. Then, the shield portion 7b is placed on the sandwiching protrusion 12a of the support portion 12, and the two core wires 7d are connected to each relay terminal 16 by a method such as soldering. Then, the cover 14 is covered from above and the bolt 14 inserted into the bolt insertion hole 13c is screwed into the female screw hole 12c of the flat portion 12b.

As a result, the shield portion 7 of the shielded wire 7 is
b is the holding projection 12a of the support portion 12 and the groove portion 1 of the cover 13.
It is sandwiched by the inner surface of 3a, and the shield portion 7b is electrically connected to the housing 9. Also, the cover 13
In the state in which is attached to the housing 9, the cover 13 and the supporting portion 12 and the housing 9 are closely contacted with each other without a gap, and the connecting portions of the two core wires 7d and the two relay terminals 16 and the shield portion 7b and the housing 9 are supported. The connecting portion with the portion 12 is covered with the cover 13, and the capacitor 6 is also located in the cover 13.

As described above, in the electric compressor 1 described above, the two core wires 7d and the shield portion covering the non-contact state between the two core wires 7d are used as power supply lines for supplying DC power from the battery 8 to the inverter circuit 4 in the housing 9. Using the shielded wire 7 provided with 7b, the two core wires 7d of this shielded wire 7 are electrically connected to the two power source input terminals 15 of the inverter circuit 4, respectively, and the shield part 7b is electrically connected to the housing 9. Since they are connected, even if electromagnetic noise generated in the inverter circuit 4 is superposed on each core wire 7d, the shield portion 7b can prevent the electromagnetic noise from being radiated to the outside. Moreover, since the shield portion 7b is electrically connected to the housing 9 so that the shield portion 7b has the same potential as the housing 9, the noise radiation can be effectively suppressed.

Further, in the above-described electric compressor 1, the connecting portions between the two core wires 7d of the shield wire 7 and the two power input terminals 15 and the connecting portion between the shield portion 7b and the housing 9 are covered by the cover 13. Since it is covered, electromagnetic noise is not radiated to the outside from each of the two power input terminals 15, the two relay terminals 16, and the connecting portions of the two relay terminals 16 and the two core wires 7d.

Further, in the above-described electric compressor 1, the housing 9 and the cover 13 are provided with a portion (holding protrusion 12a and groove portion 13a) for sandwiching the shield portion 7b by the cooperation of both, and by this sandwiching, the shield portion 7b is sandwiched. 7b
Is electrically connected to the housing 9, the shield portion 7b can be electrically connected to the housing 9 without using a joining method such as soldering, and the position of the shield wire 7 inside the cover 13 can be easily adjusted. It can be carried out.

Therefore, the battery 8 and the inverter circuit 4 can be used without using a noise removing device such as a line filter.
It is possible to reliably prevent electromagnetic noise from being radiated from a path connecting the power input terminal 15 of the vehicle, and a malfunction that may occur due to the noise radiation, specifically, an electronic device mounted on the vehicle may malfunction. It is possible to solve problems such as noise being mixed in the output voice of the audio device.

In the above description, the brushless motor 3 is illustrated as a motor for driving the compression mechanism 2, but the motor may be another type of motor capable of PWM control, such as a reluctance motor or an induction motor. Can be used as appropriate.

[0028]

As described in detail above, according to the present invention,
It is possible to prevent electromagnetic noise from being radiated from the power supply line that supplies DC power from the DC power supply to the inverter circuit in the housing.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a drive control system including an electric compressor, a power supply line, and a battery, showing an embodiment of the present invention.

FIG. 2 is a side view of the electric compressor shown in FIG.

FIG. 3 is a side view of the electric compressor shown in FIG.

FIG. 4 is an enlarged sectional view taken along the line AA and an enlarged sectional view taken along the line BB in FIG.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Electric compressor, 2 ... Compression mechanism, 3 ... Brushless motor, 4 ... Inverter circuit, 5 ... Control circuit, 6 ... Capacitor, 7 ... Shield wire, 7b ... Shield part, 7d ... Core wire,
8 ... Battery, 9 ... Housing, 10 ... Suction port, 11
... Discharge port, 12 ... Support part, 12a ... Clamping protrusion, 13 ... Cover, 13a ... Groove part, 14 ... Bolt, 15 ... Power input terminal, 16 ... Relay terminal, 17 ... Terminal.

Claims (3)

[Claims] 1. An electric compressor in which a motor for driving a compression mechanism and an inverter circuit for converting a DC voltage into a pseudo AC voltage in a pulse train and supplying the motor to a motor are housed in a metal housing. As a power supply line for supplying DC power from the power supply to the inverter circuit in the housing, a shield wire having two core wires and a shield part for covering these in a non-contact state is used, and the two core wires of the shield wire are connected to the inverter circuit. An electric compressor characterized in that it is electrically connected to two power input terminals, respectively, and a shield part is electrically connected to a housing. 2. The connecting portions between the two core wires and the two power input terminals, and the connecting portion between the shield portion and the housing,
The electric compressor according to claim 1, wherein the electric compressor is covered with a metal cover that is detachable from the housing. 3. The housing and the cover are provided with a portion for sandwiching the shield portion by cooperation between the housing and the cover, and the shield portion is electrically connected to the housing by the sandwiching. The electric compressor described in.