Electrical machinery

Abstract

An electric machine for vehicle air conditioning is provided. [Solution] The electric machine includes a first housing, a second housing, a sealing element, and a plurality of tensioning members. The first housing has a first mating surface adapted to house an electric motor, and the second housing has a second mating surface adapted to house an inverter assembly. The first and second mating surfaces are complementary and face each other. The sealing element is disposed between the first and second mating surfaces, and the second housing is adapted to mate with the first housing. The plurality of tensioning members are disposed within holes formed in the first and second mating surfaces when the first and second housings are mated.

Description

[Technical Field]

[0001] The present invention relates to electric machines, and more particularly to a connection between a motor housing and an inverter housing of the electric machine for reducing electromagnetic noise leakage from the enclosure of the electric machine. [Background technology]

[0002] Typically, a vehicle's air conditioning circuit includes an electric machine, specifically an electric compressor. The electric compressor includes a compression unit for compressing a refrigerant, an electric motor for driving the compression unit, and an inverter assembly for controlling the operation of the electric motor. Each component of the electric compressor is enclosed in a housing, and the housings are mechanically coupled to each other using various fasteners. In one embodiment, a motor housing is provided for enclosing the electric motor, and an inverter housing is provided for enclosing the inverter assembly. The electric motor of the compressor draws refrigerant into the compression unit through an inlet port formed in the motor housing, cooling the electric motor as the refrigerant circulates through the motor housing. Typically, the motor housing is cylindrical and made of aluminum, with openings at both ends. The refrigerant enters the compression unit, is compressed, and exits the electric compressor through a discharge port formed in a rear cover coupled to one end of the motor housing. The other end of the motor housing is an insertion port for the electric motor and is coupled to the inverter housing. Conventionally, the mating portions of each housing are sealed with gaskets to prevent refrigerant leakage. The gasket disposed between the motor housing and the inverter housing typically has three layers. For example, a metal base plate serves as the first layer, and rubber coatings on both sides of the base plate form the second and third layers. The inverter housing also includes high-voltage (HV) and low-voltage (LV) connector terminals. Electromagnetic noise typically occurs from the moving parts of the electric motor inside the motor housing. If the gasket is a rubber-coated metal gasket, this electromagnetic noise can propagate from the motor housing to the inverter housing. Furthermore, this electromagnetic noise propagating from the motor housing can interact with the HV and LV connector terminals. Such interaction of electromagnetic noise with the connector terminals can enter the inverter housing and cause malfunctions of the control circuit enclosed therein. Summary of the Invention [Problem to be solved by the invention]

[0003] Therefore, there is a need for an electric machine having a mechanism for preventing electromagnetic noise leakage from its housing. There is also a need for a connection formed between the motor housing and the inverter housing of the electric machine that reduces the leakage path of the electromagnetic noise by connecting it to ground. There is also a need for an electric machine having a mechanism for protecting the inverter circuit from electromagnetic noise interference.

[0004] In the description herein, elements or parameters may be indexed as a first element, a second element, etc. In this case, unless otherwise noted, this indexing is intended solely to distinguish and name similar but non-identical elements. No notion of priority should be inferred from such indexing, as these terms may be interchanged without departing from the invention. Furthermore, this indexing does not imply any order in the installation or use of the elements of the invention. [Means for solving the problem]

[0005] Accordingly, one embodiment of the present invention provides an electric machine, particularly an electric compressor for vehicle air conditioning. The electric machine includes a first housing, a second housing, a sealing element, and a plurality of tensioning members. The first housing has a first mating surface adapted to house an electric motor, and the second housing has a second mating surface adapted to house an inverter assembly. The first and second mating surfaces are complementary and face each other. The sealing element is disposed between the first and second mating surfaces, and the second housing is adapted to be mated with the first housing. The plurality of tensioning members are disposed in holes formed in the first and second mating surfaces when the first and second housings are mated.

[0006] Additionally, the sealing element has holes aligned with the holes formed in the first and second mating surfaces for passing the tensioning member therethrough.

[0007] In one embodiment, the second housing includes an extension extending radially outward therefrom, and at least one of the first and second connectors provided on a sidewall of the extension.

[0008] In one embodiment, the plurality of tensioning members are disposed on a periphery of the second mating surface in an area corresponding to at least one of the first and second connectors.

[0009] The electric machine further includes a plurality of bosses formed on the periphery of the first mating surface and the periphery of the second mating surface on sides corresponding to at least one of the first and second connectors, and the holes are formed in the bosses.

[0010] In one embodiment, the holes are formed in the first mating surface and the second mating surface at a predetermined distance apart.

[0011] In one embodiment, at least one of the distances between adjacent holes formed in the first mating surface and the second mating surface is less than 30 mm.

[0012] Furthermore, the sealing element is a rubber-coated metal gasket.

[0013] Furthermore, the tension applying members are spring pins.

[0014] In another embodiment, the electric machine further includes at least two pins formed on the second housing for aligning the first housing with the second housing.

[0015] Other features, details and advantages of the present invention can be gathered from the following description of the invention, wherein: a more complete understanding of the present invention and many of the attendant advantages thereof will be readily obtained as the same becomes better understood by reference to the following detailed description, taken in conjunction with the accompanying drawings, in which: [Brief explanation of the drawings]

[0016] [Figure 1] 1 is a block diagram of an electric machine according to one embodiment of the present invention; [Figure 2] FIG. 2 is a schematic view of a first housing of the electric machine of FIG. 1; [Figure 3] 2 is a cross-sectional view along the longitudinal axis of the electric machine of FIG. 1. [Figure 4] 2 is a schematic view of the second housing of the electric machine of FIG. 1 in a plane perpendicular to the longitudinal axis thereof; [Figure 5] 2 is an exploded view of a second housing containing an inverter assembly of the electric machine of FIG. 1; [Figure 6] FIG. 2 is an exploded view of the electric machine of FIG. 1. [Figure 7] 2 is an enlarged cross-sectional view of one of the tensioning members coupled between the first and second housings of FIG. 1; FIG. DETAILED DESCRIPTION OF THE INVENTION

[0017] It should be noted that the figures disclose the invention in sufficient detail to practice it and, if necessary, serve to more clearly define the invention, but the invention should not be limited to the embodiments disclosed herein.

[0018] The present invention relates to an electric machine, particularly an electric compressor for use in a vehicle air conditioning circuit. Generally, an electric compressor includes a motor housing housing an electric motor and an inverter housing housing an inverter assembly. The motor housing and the inverter housing are coupled to each other to enable a connection between the electric motor and the inverter. The electric motor is further connected to a compression unit that compresses a refrigerant flowing therethrough. To enable a fluid-tight connection between the motor housing and the inverter housing, a rubber-coated metal gasket is provided between the motor housing and the inverter housing. The rubber coating on the gasket transmits electromagnetic noise generated by the electric motor within the motor housing. Therefore, the gasket may transmit the electromagnetic noise to the inverter assembly, which may cause the inverter assembly to malfunction. To avoid this situation, a physical connection is provided between the inverter housing and the motor housing. This physical connection interacts with the outer housing of the electric machine, which is connected to the vehicle ground. Therefore, the intrusion of electromagnetic noise into the inverter housing is limited. The layout and function of the physical connection are further described with reference to the following figures.

[0019] FIG. 1 illustrates a block diagram of an electric machine 100 according to one embodiment of the present invention. In this embodiment, the electric machine 100 is an electric compressor, specifically an inverter-integrated electric compressor 100. The electric machine 100 is provided in a refrigerant circuit of a vehicle. Generally, the electric machine 100 is provided in the refrigerant circuit of the vehicle and compresses a refrigerant flowing therethrough. The electric machine 100 includes a first housing 110 adapted to house an electric motor 112, a second housing 120 adapted to house an inverter assembly 122, and a third housing 130 adapted to house a compression unit 132. Furthermore, the first housing 110, the second housing 120, and the third housing 130 are fastened together by fastening means (not shown), such as bolts, to form a housing for the electric machine 100. In one embodiment, the first housing 110, the second housing 120, and the third housing 130 are formed of metal, specifically aluminum die-cast.

[0020] The electric motor 112 provided in the first housing 110 includes a stator and a rotor (not shown in FIG. 1 ). A rotating shaft 134 is connected to the rotor, and the rotating shaft 134 extends into the third housing 130 and is coupled to the compression unit 132. The first housing 110, which serves as the motor housing, is cylindrical with openings at both ends to accommodate the electric motor 112. One end of the first housing 110 is coupled to the third housing 130, which includes the compression unit 132. The other end of the first housing 110 is an insertion opening for the electric motor 112 and is coupled to the second housing 120, which includes the inverter assembly 122. When the electric motor 112 is energized, the rotating shaft 134 drives the compression unit 132 provided in the third housing 130.

[0021] The compression unit 132 provided in the third housing 130 includes a fixed scroll and an orbiting scroll for compressing the refrigerant flowing therethrough. In one embodiment, the fixed scroll is fixedly and integrally formed with the third housing 130. The orbiting scroll is rotatably connected to an eccentric pin formed by a rotary shaft 134 extending from the first housing 110. The orbiting scroll is adapted to compress the refrigerant in a compression space defined between the fixed scroll and the orbiting scroll when the rotary shaft 134 is rotated by the electric motor 112. That is, the orbiting motion of the orbiting scroll relative to the fixed scroll compresses the refrigerant in the compression space. Furthermore, a suction port 136 for drawing the refrigerant into the electric machine 100 is integrally formed with the first housing 110. The refrigerant drawn through the suction port 136 of the first housing 110 flows through the electric motor 112, cools or absorbs heat generated by the electric motor 112, and can enter the third housing 130 for the compression process. The compressed refrigerant then exits the electric machine 100 through a discharge port 150 integrally formed with the third housing 130 .

[0022] The inverter assembly 122 contained in the second housing 120, which is an inverter housing, is adapted to drive the electric motor 112 in a controlled manner. The inverter assembly 122 includes a number of electronic components mounted on a circuit board to perform the necessary operations. The circuit board receives power from an external power source, such as a vehicle battery. The circuit board is shown in FIG. 5 . Additionally, a hermetic terminal 142 is provided on an end wall of the second housing 120 and is adapted to couple with the electric motor 112. The inverter assembly 122 generates a controlled input for the electric motor 112 and transmits the input to the electric motor 112 via the hermetic terminal 142. Furthermore, the input generated by the inverter assembly 122 can control the speed of the electric motor 112.

[0023] FIG. 2 shows a schematic diagram of the first housing 110 of the electric machine 100 of FIG. 1 . The electric motor 112 is not shown in FIG. 2 . In one embodiment, the first housing 110 includes an annular wall 208 extending over a certain distance so as to be formed as a cylinder. Furthermore, the first housing 110 includes a first mating surface 202 defined at a longitudinal end of its A-side. In one example, the first housing 110 is hollow cylindrical, and its inner circumferential surface defines an opening on the A-side. Furthermore, the first housing 110 has openings on both sides for coupling with the second housing 120 and the third housing 130, respectively. In one example, the opening formed on the A-side of the first housing 110 is adapted to align with the second housing 120, and the opening formed on the B-side of the first housing 110 is adapted to align with the third housing 130. Additionally, the third housing 130 is mechanically coupled to an opening defined in the B-side of the first housing 110 by any connecting means, which may be a plurality of threads and bolts. In one embodiment, the electric motor 112 is inserted into the first housing 110 through an opening defined in the A-side thereof.

[0024] Additionally, intake port 136 protrudes from annular wall 208 of first housing 110, as shown in Figure 2. In one embodiment, first housing 110 may further include mounting features on its outer surface that allow electric machine 100 to be mounted to a vehicle body.

[0025] Furthermore, at least two positioning holes 210A, 210B are provided at a predetermined distance apart on the outer and / or inner periphery of the first mating surface 202. These holes are for receiving any connecting means, such as positioning pins, thereby enabling efficient positioning between the first housing 110 and the second housing 120. Specifically, the positioning holes 210A, 210B are provided at opposite positions on the periphery of the first mating surface 202 across the central axis of the first housing 110.

[0026] The first housing 110 further includes a plurality of holes 204A-D formed in the first mating surface 202 at predetermined distances apart. In one embodiment, the plurality of holes 204A-D are formed on the periphery of the first mating surface 202. According to this embodiment, as shown in FIG. 2, a plurality of bosses 206A-D are provided on the outer periphery of the opening. That is, the plurality of bosses 206A-D are formed on the outer surface of the first housing 110 around the periphery of the opening defined in the first housing 110. Furthermore, the plurality of bosses 206A-D have a plurality of holes 204A-D formed therein.

[0027] Figure 3 shows a cross-sectional view of electric machine 100 in a plane perpendicular to the longitudinal axis of electric machine 100 in Figure 1. Second housing 120 includes a base plate 302 and a peripheral wall 306 extending from the outer edge of base plate 302, which define a space for accommodating inverter assembly 122. In one embodiment, base plate 302 is contoured to accommodate electronic components 320 of inverter assembly 122.

[0028] 3, the second housing 120 includes an extension portion 316 that extends radially outward from the outer diameter of the first housing 110. In one embodiment, the base plate 302 of the second housing 120 includes a lower portion 308A that is complementary to the opening in the first housing 110 and an upper portion 308B that forms the sidewall 304 of the extension portion 316. Furthermore, the lower portion 308A of the second housing 120 is annular in shape and adapted to mate with the first housing 110.

[0029] 1 and 4 , the hermetic terminal 142 is provided on the lower portion 308A of the base plate 302 of the second housing 120. The inverter assembly 122 and the electric motor 112 are electrically connected via the hermetic terminal 142. The lower portion 308A of the second housing 120 includes a second mating surface 310 that is complementary to and faces the first mating surface 202 of the first housing 110.

[0030] Additionally, second mating surface 310 includes a plurality of holes 312A-D formed thereon. In one embodiment, holes 312A-D formed in second mating surface 310 are complementary to holes 204A-D formed in first mating surface 202. Additionally, second mating surface 310 includes a plurality of bosses 314A-D. In one embodiment, bosses 314A-D are formed around the periphery of second mating surface 310.

[0031] 3 and 4, second housing 120 further includes at least two connectors 318A-B on sidewall 304 of extension portion 316. The two connectors 318A-B include at least a first connector 318A and a second connector 318B for providing electrical energy and signals to inverter assembly 122. In one embodiment, first connector 318A is a high-voltage terminal and second connector 318B is a low-voltage terminal.

[0032] As shown in FIGS. 3 and 5 , the inverter assembly 122 further includes a plurality of electronic components 320 mounted on a circuit board 138 for control operation. As shown in FIG. 5 , the circuit board 138 is disposed within the inverter assembly's housing and secured to the base plate 302 with a plurality of bolts / screws 228. The first connector 318A and the second connector 318B are electrically connected to the electronic components 320 mounted on the circuit board 138 of the inverter assembly 122 via bus bars and / or electrical wires. In one embodiment, the high-voltage terminal 318A provides a high voltage to an inverter designed using the electronic components 320. Such an inverter converts high-voltage DC power into three-phase AC power and transmits the power to the electric motor 112 mounted in the first housing 110. Furthermore, the low-voltage terminal 318B supplies low-voltage DC power to a control unit designed using the electronic components 320. The control unit controls the electric motor 112, such as the rotation speed and number of rotations of the rotor, and turning the electric motor 112 on and off.

[0033] In a preferred embodiment, a plurality of bosses 206A-D, 314A-D are formed on the periphery of the first mating surface 202 of the first housing 110 and the periphery of the second mating surface 310 of the second housing 120 on sides corresponding to the connectors 318A-B. In one example, the bosses 206A-D formed on the first mating surface 202 are complementary to the bosses 314A-D formed on the second mating surface 310.

[0034] FIG. 6 is an exploded view of the electric machine 100 of FIG. 1 , illustrating the connection between the first housing 110 and the second housing 120. As described above, the first mating surface 202 of the first housing 110 is complementary to and adapted to mate with the second mating surface 310 of the second housing 120. Furthermore, a sealing element 402 is provided between the first mating surface 202 and the second mating surface 310. The sealing element 402 forms a fluid-tight connection between the first housing 110 and the second housing 120. In one embodiment, the sealing element 402 is a gasket composed of three layers. For example, the first layer may be made of a metal material, and rubber coated on both sides of the first layer forms the second and third layers. The sealing element 402 contacts the first mating surface 202 and the second mating surface 310 when the first housing 110 and the second housing 120 are joined together.

[0035] The sealing element 402 further includes holes 404A-D formed in its periphery. In one embodiment, the holes 404A-D align with the holes 204A-D, 312A-D formed in the first mating surface 202 of the first housing 110 and the second mating surface 310 of the second housing 120.

[0036] The electric machine 100 further includes a plurality of tensioning members 406A-D. The plurality of tensioning members 406A-D are disposed within holes 204A-D, 312A-D formed in the first mating surface 202 and the second mating surface 310 when the first housing 110 and the second housing 120 are coupled together. In one embodiment, the plurality of tensioning members 406A-D are spring pins. Furthermore, the plurality of tensioning members 406A-D are made of a metallic material.

[0037] In one embodiment, multiple tensioning members 406A-D are disposed in an area corresponding to at least one of first connector 318A and second connector 318B around the periphery of second mating surface 310. As shown in FIGS. 4 and 6, holes 312A-D and the tensioning members 406A-D inserted therein are disposed in an area between connectors 318A-B and the interior of second mating surface 310 where electromagnetic noise is generated.

[0038] In another embodiment, the tensioning members 406A-D are adapted to elastically deform along their radial direction as they are inserted into the holes 204A-D, 312A-D formed in the first mating surface 202 and the second mating surface 310. In one example, the outer diameter of the tensioning members 406A-D is equal to or greater than the inner diameter of the holes 204A-D, 312A-D. If the diameter of the holes 204A-D, 312A-D is the same as the diameter of the tensioning members 406A-D, then the tensioning members 406A-D must elastically deform along their radial direction to facilitate insertion of the tensioning members 406A-D into the holes 204A-D, 312A-D. In this embodiment, one ends of the plurality of tension application members 406A-D are inserted into the holes 312A-D formed in the second mating surface 310. Then, the plurality of tension application members 406A-D provided in the holes 312A-D of the second mating surface 310 are passed through the holes 404A-D formed in the sealing member 402, and the sealing member 402 is disposed on the second mating surface 310 of the second housing 120. Furthermore, when the first housing 110 is joined to the second housing 120 to form the enclosure of the electric machine 100, the other ends of the plurality of tension application members 406A-D are inserted into the holes 204A-D formed in the first mating surface 202. When the plurality of tension application members 406A-D are provided between the first housing 110 and the second housing 120, the plurality of tension application members 406A-D enable physical contact between the first housing 110 and the second housing 120. Furthermore, the body of the second housing 120 is connected to the ground of the vehicle. When the plurality of tension application members 406A-D enable physical contact between the first housing 110 and the second housing 120, electromagnetic noise generated by the electric motor 112 of the first housing 110 is connected to the ground via the second housing 120.

[0039] Providing multiple tension application members 406A-D in regions corresponding to connectors 318A-B between first housing 110 and second housing 120 can prevent electromagnetic noise from propagating to connectors 318A-B, thereby preventing interaction between electronic components 320 provided in inverter assembly 122 and electromagnetic noise.

[0040] FIG. 7 shows an enlarged cross-sectional view of one of the tension application members 406A-D secured between the first housing 110 and the second housing 120. Furthermore, the tension application members 406A-D are made of a metallic material with high electrical conductivity and EMC / EMI shielding properties, such as copper, iron, steel, or aluminum. In one embodiment, the tension application members 406A-D each include a cylindrically elongated pin body with a longitudinal slit. Furthermore, both ends of the pin body have inclined surfaces. These surfaces allow the tension application members 406A-D to be easily inserted into the holes 204A-D, 312A-D when assembling the first housing 110 and the second housing 120. In one embodiment, the distance between adjacent tension application members 406A-D is less than 30 mm. 6, at least two solid metal pins 408 are inserted into locating holes 410A and 410B formed in the second housing 120 to align the first housing 110 with the second housing 120. Furthermore, the locating holes 410A-B formed in the second housing 120 are complementary to the locating holes 210A-B formed in the first housing 110.

[0041] As described above, the outer diameter of the tensioning members 406A-D is equal to or greater than the inner diameter of the holes 204A-D, 312A-D. This can provide a high coefficient of friction between the outer barrel of the tensioning members 406A-D and the inner walls of the holes 204A-D, 312A-D, thereby retaining the tensioning members 406A-D within the holes 204A-D, 312A-D. The tensioning members 406A-D are inserted into the respective holes 204A-D, 312A-D in the first housing 110 and the second housing 120 by radially deforming the members so that both ends of the members can be inserted into the holes. In one embodiment, the tensioning members 406A-D each have a length of 14 mm. In one embodiment, the portions of the pin bodies of the tension application members 406A-D that are inserted into the holes 204A-D in the first housing 110 are larger than the portions that are inserted into the holes 312A-D in the second member 120.

[0042] All the above-mentioned embodiments are merely for the purpose of illustrating the present invention, and many more embodiments and combinations thereof may exist, so the present invention should not be limited to only the above-mentioned embodiments. [Explanation of symbols]

[0043] 100 Electrical Machinery 110 First Housing 112 Electric Motor 120 Second Housing 122 inverter assembly 130 Third Housing 132 Compression Unit 134 Rotational Axis 136 Intake port 138 Circuit Board 142 Airtight terminal 150 discharge port 208 annular wall of first housing 202 first mating surface of first housing 204A~D First mating surface holes 206A~D First mating surface boss 210A, B Positioning holes in first housing 228 bolts / screws 302 Second housing base plate 304 Sidewall of Extension 306 Peripheral wall of second housing 308A Lower part of base plate 308B Upper part of base plate 310 second mating surface of second housing 312A~D Second mating surface holes 314A~D Second mating surface boss 316 Second housing extension 318A First Connector 318B Second Connector 320 Electronic Components 402 Sealing Elements 404A~D Holes in sealing elements 406A~D Tension application members 408 pins 410A, B Positioning holes in second housing

Claims

1. An electric machine (100) comprising: a first housing (110) having a first mating surface (202) and adapted to house an electric motor (112); a second housing (120) having a second mating surface (310) adapted to house an inverter assembly (122), the first mating surface (202) and the second mating surface (310) being complementary and facing each other; a sealing element (402) disposed between the first mating surface (202) and the second mating surface (310), the sealing element (402) adapted to couple the second housing (120) with the first housing (110); a plurality of tension application members (406A-D) provided in holes (204A-D, 312A-D) formed in the first mating surface (202) and the second mating surface (310) when the first housing (110) and the second housing (120) are coupled; Equipped with the second housing (120) includes an extension portion (316) extending radially outward therefrom and at least one of first and second connectors (318A, 318B) provided on a side wall (304) of the extension portion (316); the plurality of tension application members (406A-D) are disposed in a region of the periphery of the second mating surface (310) corresponding to at least one of the first and second connectors (318A, 318B); The electric machine (100) wherein the plurality of tensioning members (406A-D) are spring pins.

2. 2. The electric machine of claim 1, wherein the sealing element has holes aligned with the holes formed in the first mating surface and the second mating surface for passing the tensioning members.

3. 2. The electric machine of claim 1, further comprising a plurality of bosses formed on a periphery of the first mating surface and a periphery of the second mating surface on sides corresponding to at least one of the first and second connectors, wherein the holes are formed in the bosses.

4. The electric machine (100) of any one of claims 1 to 3, wherein the holes (204A-D, 312A-D) are formed in the first mating surface (202) and the second mating surface (310) at a predetermined distance apart.

5. 5. The electric machine (100) of claim 1, wherein at least one of the distances between adjacent holes (204A-D, 312A-D) formed in the first mating surface (202) and the second mating surface (310) is less than 30 mm.

6. The electric machine (100) of any one of claims 1 to 5, wherein the sealing element (402) is a rubber-coated metal gasket.

7. The electric machine (100) of any one of claims 1 to 6, further comprising at least two pins (408) formed on the second housing (120) for aligning the first housing (110) with the second housing (120).

8. An electric machine (100) as described in any one of claims 1 to 7, wherein the spring pin is made of metal.

9. An electric machine (100) as described in any one of claims 1 to 8, wherein the spring pin is elastically deformed along the radial direction.

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