Inverter-Integrated Electric Compressor
Provided is an inverter-integrated electric compressor excellent in joining strength and joining reliability at electrical joint. An inverter-integrated electric compressor wherein a motor is incorporated and a motor drive circuit including the inverter is surrounded by a compressor housing, characterized in that a bus bar joint section at which bus bars are electrically joined together is provided in the motor drive circuit, and a tip of at least one of the bus bars, the tip being located at the bus bar joint section, is split into small joining sections.
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The present invention relates to an inverter-integrated electric compressor in which a motor drive circuit including an inverter is mounted in a compressor, and specifically relates to an inverter-integrated electric compressor which is designed to improve the working efficiency for mounting an electronic component such as IPM, which is weak to thermal stress, in the motor drive circuit.
BACKGROUND ART OF THE INVENTIONAs disclosed in Patent document 1, known is a structure of an inverter-integrated electric compressor in which a motor drive circuit including an inverter is mounted in a compressor, where the motor drive circuit is coated with insulative resin coating material, and where the motor drive circuit, lead wires and connection terminals are provided in a closed space surrounded by a metal wall. In the motor drive circuit of the compressor, used are electronic components, such as IPM (Intelligent Power Module) having an inverter function and being weak to heat.
In addition, known is a joint structure body which consists of joined members configuring an electric circuit, wherein a joint has a plurality of joining spots, as shown in Patent document 2. Such a joining structure body is provided with a plurality of joining spots at a joint section, so that the joint section is ensured to have sufficient strength.
PRIOR ART DOCUMENTS Patent documents
- Patent document 1: JP2008-202564-A
- Patent document 2: JP2004-185953-A
In the inverter-integrated electric compressor which is disclosed in Patent document 1, terminals such as a bus bar can be used at an electrical joint. In such a case, the terminals can be connected to each other with bolts or screws, and alternatively can be connected to each other by welding. However in a case where components have to be mounted in a predetermined space, the welding may be the only method applicable.
However, because an inverter-integrated electric compressor requires electric current greater than general compressors, when the contact resistance at the joint section is comparatively high, heat generation from the joint section might adversely affect various devices. In addition, when a compressor is mounted to an automotive engine as being used in an air conditioning system for vehicles, the joint section is required to have joining strength and joining reliability enough to endure a severe condition of high temperature in an engine room.
Therefore, being focused on the above described problems, an object of the present invention is to provide an inverter-integrated electric compressor, which is excellent in joining strength and joining reliability at the electrical joint.
Means for Solving the ProblemsTo achieve the above described object, an inverter-integrated electric compressor according to the present invention is an inverter-integrated electric compressor, wherein a motor is incorporated and a motor drive circuit including an inverter is provided in a housing space surrounded by a compressor housing, characterized in that a bus bar joint section at which bus bars are joined together to connect electrically is provided in the motor drive circuit, and a tip, which is located at the bus bar joint section, of at least one of the bus bars is split into small joining sections.
Because the tip, which is located at the bus bar joint section connecting the bus bars electrically, of at least one of the bus bars is split into small joining sections in the inverter-integrated electric compressor according to the present invention, each other's bus bar can be joined at a plurality of spots, so that the connection strength and the connection reliability can be ensured. In addition, because they can contact with a large contact area, contact resistance at the joint section can be reduced. Further, in employing a joint method such as welding which requires to be heated, thermal stress to electronic components can be reduced in the present invention more than in a conventional method where the total area of welded spots are concentrated to one spot. In the present invention, welding is performed as dispersed to a plurality of welded spots, so that energy (Voltage×Current×Weld time, for example) applied in the weld time can be suppressed. Furthermore, because welded spots are dispersed and therefore each welded area is segmentalized, a welding machine and a clamping jig which are used in welding can be downsized, so that the productivity of compressors is improved.
In the present invention, it is possible that the tips of both bus bars are provided with small joining sections. Because the tips of both bus bars are provided with similar small joining sections, relative positioning between bus bars can be easily performed. In a case where the bus bar of the inverter-integrated electric compressor of the present invention is welded by a TIG welding, if the tips of both bus bars are provided with small joining sections, the arc for the TIG welding can be accurately jetted toward the spot to be welded, so that the connection reliability at the welded spot is ensured.
Because the motor drive circuit board is often provided with a lot of electronic components which are weak to thermal stress, the present invention makes it possible to effectively achieve reducing thermal load in a case where at least one of the bus bars is connected to a board of the motor drive circuit. As well, because IPM is weak to thermal stress, the present invention makes it possible to effectively achieve reducing thermal load in a case where at least one of bus bars is provided on an IPM. Furthermore, it is preferable that at least one of the bus bars is provided as standing up from the board of the motor drive circuit. Thus the bus bar is provided as standing up from the board, so as to make it easy to perform relative positioning with the bus bar provided in a member, such as a case member, which houses the motor drive circuit.
The inverter-integrated electric compressor according to the present invention is applicable to all types of compressors substantially, and specifically, is suitably used as a compressor for automotive air conditioning systems which are often installed in a narrow space and are sensitive to thermal stress. In addition, when the compressor is mounted to an automotive engine, the joint section can be given joining strength and joining reliability enough to endure a severe condition of high temperature in an engine room.
Effect according to the InventionIn the inverter-integrated electric compressor according to the present invention, the tip of at least one of the bus bars is split into small joining sections at the bus bar joint section, so that the connection strength and the connection reliability can be improved. Further, because the joint section can contact with a large contact area, contact resistance is reduced so as to suppress heat generation even when great electric current flows into the joint section under operation of the compressor. Furthermore, because the tips of both bus bars are segmentalized into small joining sections, relative positioning between the bus bars can be easily performed and the productivity of the compressor can be improved.
Hereinafter, desirable embodiments will be explained as referring to figures.
Motor drive circuit 21 for motor 7 is provided in compressor housing 12 (front housing). In more detail, motor drive circuit 21 is provided at the external side of partition wall 22 which is formed in compressor housing 12 against the side of refrigerant suction passageway. Motor drive circuit 21 supplies electricity through seal terminal 23 (an output terminal of motor drive circuit 21), which is attached thereto by penetrating partition wall 22, and lead wire 24 to motor 7, while the refrigerant suction passageway side and the side of motor drive circuit 21 are sealed in the placement part of motor 7. Because motor drive circuit 21 is provided at the external side of partition wall 22, at least one part of electric components including motor drive circuit 21 can be cooled with sucked refrigerant by heat exchange.
Motor drive circuit 21 includes IPM (Intelligent Power Module) 25 having inverter function and control circuit 26, and electric components such as capacitor 27 are provided either integrally with it or separately from it. Motor drive circuit 21 is connected to an external power supply (not shown) through connector 28 as an input terminal. The aperture side to the outside of compressor housing 12, which mounts these electric components including motor drive circuit 21, is covered as sealed with lid member 29, and these electric components are protected by lid member 29.
The above-described configuration can be shown like an electric circuit, as in
The inverter-integrated electric compressor according to the present invention is applicable to all types of compressors substantially, and specifically suitably used as a compressor for an automotive air conditioning system which is mounted in a narrow space and is sensitive to thermal stress.
EXPLANATION OF SYMBOLS
- 1: inverter-integrated electric compressor
- 2: compression mechanism
- 3: fixed scroll
- 4: movable scroll
- 5: ball coupling
- 6: compressor housing (center housing)
- 7: motor
- 8: main shaft
- 9: eccentric pin
- 10: eccentric bush
- 11: suction port
- 12: compressor housing (front housing)
- 13: discharge hole
- 14: discharges chamber
- 15: compressor housing (rear housing)
- 16: discharge port
- 21: motor drive circuit
- 22: partition wall
- 23: seal terminal
- 24: lead wire
- 25: IPM
- 26: control circuit
- 27: capacitor
- 28: connector
- 29: lid member
- 30: high voltage circuit for motor drive
- 31: shield plate
- 37: noise filter
- 41: motor wire wrap
- 42: inverter
- 43: power element
- 44: motor control circuit
- 45: low voltage circuit for control
- 46: external power supply
- 47: connector for high voltage
- 48: air conditioning system
- 49: connector for control signal
- 58: case member
- 59: component affixing hole
- 60, 70, 80, 90: bus bar
- 61, 71, 81, 91: small joining section
Claims
1. An inverter-integrated electric compressor, wherein a motor is incorporated and a motor drive circuit including an inverter is provided in a housing space surrounded by a compressor housing, wherein a bus bar joint section at which bus bars are joined together to connect electrically is provided in said motor drive circuit, and that a tip, which is located at said bus bar joint section, of at least one of said bus bars is split into small joining sections.
2. The inverter-integrated electric compressor according to claim 1, wherein said tips of both bus bars are provided with small joining sections.
3. The inverter-integrated electric compressor according to claim 1, wherein at least one of said bus bars is provided as standing up from a board of said motor drive circuit.
4. The inverter-integrated electric compressor according to claim 1, wherein at least one of said bus bars is provided on an IPM.
5. The inverter-integrated electric compressor according to claim 1, wherein said joining is performed by a TIG welding.
6. The inverter-integrated electric compressor according to claim 1, wherein the compressor is a compressor used for automotive air conditioning systems.
7. The inverter-integrated electric compressor according to claim 6, wherein said compressor is mounted to an automotive engine.
Type: Application
Filed: Nov 6, 2009
Publication Date: Sep 1, 2011
Applicant: Sanden Corporation (Gunma)
Inventors: Atsushi Saito (Gunma), Makoto Shibuya (Gunma), Kazumi Ohsato (Gunma), Tadashi Kuribara (Gunma)
Application Number: 13/128,140
International Classification: F04B 17/03 (20060101);