Motor compressor

Abstract

To provide a motor compressor which attains high cooling performance for switching elements compared to conventional motor compressors.SOLUTION: In a motor compressor, a plurality of switching elements 61 forming an inverter 6 are fixed to an element installation part 79 provided within an inverter housing 7 by a pressing member 20. The pressing member 20 has: a plurality of fixing parts 25a to 25d which are respectively fixed to pressing member attachment parts provided within the inverter housing 7; and a plurality of element pressing parts 27 each of which presses one of the switching elements 61 against the element installation part 79. The pressing member is made of a material having thermal conductivity.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to an electric compressor.

Background Art

[0002] As an electric compressor used for compressing a refrigerant in a vehicle air conditioner or the like, an electric compressor in which an inverter is integrally incorporated is known. In this type of electric compressor, the inverter includes a plurality of switching elements (such as IGBTs and power MOS transistors), and each of the plurality of switching elements is fixed at a predetermined position by screwing.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0004] In recent years, due to the increase in the capacity of electric compressors and the accompanying increase in rated power, the voltage input to the switching elements has become higher. Therefore, the temperature of the switching elements tends to become higher, and countermeasures are required.

[0005] Therefore, an object of the present invention is to provide an electric compressor capable of obtaining higher cooling performance for switching elements than in the prior art.

Means for Solving the Problems

[0006] According to one aspect of the present invention, a novel electric compressor is provided. The provided electric compressor includes an electric motor that rotates a rotating shaft, a compression mechanism driven by the rotation of the rotating shaft, and an inverter that drives and controls the electric motor, and the inverter is housed in an inverter housing. The inverter includes a plurality of switching elements, and the plurality of switching elements are fixed to an element installation portion provided in the inverter housing by a pressing member. The pressing member has a plurality of fixing portions fixed to a mounting portion provided in the inverter housing, and a plurality of pressing portions each pressing one of the plurality of switching elements against the element installation portion, and is formed of a material having thermal conductivity.

Effects of the Invention

[0007] According to the present invention, it is possible to provide an electric compressor capable of obtaining higher cooling performance for switching elements as compared with the prior art.

Brief Description of the Drawings

[0008]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Embodiments for Carrying Out the Invention

[0009] FIG. 1 is a schematic cross-sectional view of an electric compressor 1 according to an embodiment of the present invention. The electric compressor 1 according to the embodiment is an inverter-integrated type electric compressor in which an inverter is integrally incorporated. The electric compressor 1 is mounted on a vehicle, for example, and constitutes a part of a refrigerant circuit of a vehicle air conditioner, and is configured to compress and discharge a refrigerant.

[0010] The electric compressor 1 includes a rotating shaft 2, an electric motor 3, a compression mechanism 4, a main body housing 5, an inverter 6, an inverter housing 7, and a cover member 8.

[0011] The rotating shaft 2 is rotatably supported by the main body housing 5 by a bearing (not shown). The electric motor 3 is, for example, a three-phase synchronous motor, and is configured to be driven by power supplied from the inverter 6 to rotate the rotating shaft 2. The compression mechanism 4 is configured to be driven by the rotation of the rotating shaft 2 to compress a refrigerant. Although not particularly limited, the compression mechanism 4 may be a scroll compression mechanism. The main body housing 5 is made of metal (for example, aluminum die-cast), has a cylindrical cross-section, and houses the rotating shaft 2, the electric motor 3, and the compression mechanism 4 therein. Inside the main body housing 5, the electric motor 3 and the compression mechanism 4 are arranged in series.

[0012] The inverter 6 drives and controls the electric motor 3. The inverter housing 7 is provided integrally with the main body housing 5 and houses the inverter 6 therein. In the present embodiment, the inverter housing 7 is provided at an end of the main body housing 5 on the electric motor 3 side and has a larger projected area than the main body housing 5. The inverter housing 7 is mainly formed by a bottom wall 71 and a peripheral wall 73 rising from the periphery of the bottom wall 71, and has an opening 75 facing the bottom wall 71. The opening 75 of the inverter housing 7 is closed by the cover member 8. The cover member 8 is fixed to the peripheral wall of the inverter housing 7 (which is also a part of the main body housing 5) by screws (not shown).

[0013] A power connector (HV connector) 9 for supplying DC power from an in-vehicle battery (not shown) as an external power source to the inverter 6 is fixed to the bottom wall 71 of the inverter housing 7. That is, the power connector 9 electrically connects the in-vehicle battery (external power source) and the inverter 6. Also, a part of the bottom wall 71 of the inverter housing 7 forms a partition wall 77 that separates the inside of the main body housing 5 from the inside of the inverter housing 7.

[0014] The main body housing 5 is formed with an inlet 5a for allowing the refrigerant to flow into the main body housing 5 and an outlet 5b for allowing the refrigerant to flow out of the main body housing 5. The inlet 5a is configured to allow the refrigerant to flow between the partition wall 77 and the electric motor 3 in the main body housing 5. The refrigerant flowing into the main body housing 5 from the inlet 5a flows along the partition wall 77, passes through the electric motor 3, reaches the compression mechanism 4, and is compressed by the compression mechanism 4. Then, the refrigerant compressed by the compression mechanism 4 flows out from the outlet 5b.

[0015] The refrigerant flowing into the main body housing 5 from the inlet 5a is a low-temperature gas refrigerant. Therefore, the partition wall 77 (the bottom wall 71 of the inverter housing 7) and the electric motor 3 can be cooled by the refrigerant flowing into the main body housing 5 from the inlet 5a.

[0016] The inverter 6 will be further described. The inverter 6 is configured to convert the DC power supplied from the in-vehicle battery via the power connector 9 into three-phase AC power and supply it to the electric motor 3 via, for example, the power supply line 10 extending through the partition wall 77. The inverter 6 includes a plurality of switching elements, specifically six switching elements 61 (only one of which is shown in FIG. 1), and a circuit board 63 on which a control circuit 65 for controlling the operation of the six switching elements 61 is mounted. The switching element 61 is a power semiconductor switching element such as an IGBT or a power MOS transistor. In this embodiment, in addition to the control circuit 65, various circuit elements including a capacitor 67 and a coil (not shown) constituting a noise filter are mounted on the circuit board 63.

[0017] The six switching elements 61 are fixed to an element installation portion 79 provided in the inverter housing 7 by a pressing member 20 (described later). The element installation portion 79 is formed on the surface of the partition wall 77 on the side of the inverter housing 7, that is, on the inner surface of the bottom wall 71 of the inverter housing 7 (the inner bottom surface of the inverter housing 7). Although not particularly limited, the element installation portion 79 can be a machined surface of the inner surface of the bottom wall 71 of the inverter housing 7 (the inner bottom surface of the inverter housing 7). The element installation portion 79 has a function as a heat dissipation portion that dissipates the heat of the six switching elements 61 by using the low-temperature gas refrigerant flowing into the main body housing 5.

[0018] The circuit board 63 is fixed to the upper surfaces of a plurality of board mounting portions 11 provided in the inverter housing 7 by screws 13. The board mounting portions 11 are formed to project from the inner surface of the bottom wall 71 of the inverter housing 7 (the inner bottom surface of the inverter housing 7). Therefore, in this embodiment, the circuit board 63 is disposed closer to the cover member 8 than the six switching elements 61 in the inverter housing 7, that is, separated from the six switching elements 61 toward the cover member 8 side (upward in FIG. 1).

[0019] Each of the six switching elements 61 has a lead 61a extending toward the circuit board 63, and more specifically, a lead 61a extending through the circuit board 63. And these leads 61a are soldered to the circuit board 63, for example, so that the six switching elements 61 and the circuit board 63 are electrically connected.

[0020] Here, with reference to FIGS. 2 to 4, the fixing structure of the switching element 61 in the inverter 6 of the electric compressor 1 according to the embodiment will be described. FIG. 2 is a front view of the fixing structure of the switching element 61, FIG. 3 is a plan view of the fixing structure of the switching element 61, and FIG. 4 is an exploded perspective view of the fixing structure of the switching element 61.

[0021] As shown in FIGS. 2 to 4, the fixing structure of the switching element 61 includes a pressing member 20 for fixing the six switching elements 61 to the element installation portion 79 provided in the inverter housing 7. The pressing member 20 is formed of a material having thermal conductivity. Preferably, the pressing member 20 is formed in a plate shape from a springy metal material. The pressing member 20 is disposed between the six switching elements 61 and the circuit board 63. The pressing member 20 is fixed within the inverter housing 7 so as to press the six switching elements 61 against the element installation portion 79 and fix the six switching elements 61 to the element installation portion 79.

[0022] In the present embodiment, the six switching elements 61 are arranged in two rows of three each on the element installation portion 79 such that the respective leads 61a are on the inner side, and are arranged in a rectangular shape in plan view as a whole.

[0023] Correspondingly, the pressing member 20 is also formed in a rectangular shape in plan view as a whole. Specifically, the pressing member 20 has a main body portion 21 that is rectangular in plan view. The main body portion 21 of the pressing member 20 has a size corresponding to the entirety of the six switching elements 61 arranged in a rectangular shape in plan view on the element installation portion 79, that is, a size capable of covering the six switching elements 61 (it is not necessary to be a size that strictly covers them, as long as it can generally cover the six switching elements 61). Further, at least one opening is formed in the main body portion 21 of the pressing member 20 for passing the leads 61a of the six switching elements 61. In the present embodiment, one opening 23 through which the leads 61a of the six switching elements 61 can be passed together is formed at approximately the center of the main body portion 21 of the pressing member 20 in plan view. However, it is not limited to this, and a plurality of openings each capable of passing a part of the leads 61a of the six switching elements 61 may be formed in the main body portion 21 of the pressing member 20.

[0024] Further, the pressing member 20 has a plurality (here, four) of fixing portions 25a to 25d for fixing itself (that is, the pressing member 20) within the inverter housing 7. The four fixing portions 25a to 25d of the pressing member 20 are each fixed to the corresponding pressing member mounting portions 15a to 15d provided within the inverter housing 7 by screws 17. Thereby, the pressing member 20 is fixed within the inverter housing 7, and thus the six switching elements 61 are fixed to the element installation portion 79.

[0025] In this embodiment, the four pressing member mounting portions 15a to 15d are provided at intervals from each other so as to surround the six switching elements 61 on the element installation portion 79. Similar to the substrate mounting portion 11, the four pressing member mounting portions 15a to 15d are formed to protrude from the inner surface of the bottom wall 71 of the inverter housing 7 (the inner bottom surface of the inverter housing 7). Here, the four pressing member mounting portions 15a to 15d are formed on the element installation portion 79. However, the present invention is not limited to this, and the four pressing member mounting portions 15a to 15d may be formed around the element installation portion 79, or a part thereof may be formed on the element installation portion 79 and the rest may be formed around the element installation portion 79.

[0026] The four fixing portions 25a to 25d of the pressing member 20 extend outward from the main body portion 21 so as to correspond to the four pressing member mounting portions 15a to 15d. The four fixing portions 25a to 25d of the pressing member 20 are fixed to the upper surfaces of the corresponding pressing member mounting portions 15a to 15d by screws 17, respectively. Therefore, the four fixing portions 25a to 25d of the pressing member 20 are arranged at intervals from each other so as to surround the six switching elements 61 in a plan view, similar to the four pressing member mounting portions 15a to 15d.

[0027] Specifically, in this embodiment, the four pressing member mounting portions 15a to 15d provided in the inverter housing 7 are provided at equal intervals in the circumferential direction (it is not necessary to be exactly equal intervals, and generally equal intervals are sufficient. The same applies hereinafter) so as to surround the six switching elements 61 on the element installation portion 79. Correspondingly, the four fixing portions 25a to 25d of the pressing member 20 are also arranged at equal intervals in the circumferential direction so as to surround the six switching elements 61 on the element installation portion 79 in a plan view. Further, each of the four fixing portions 25a to 25d of the pressing member 20 extends outward from the center (it is not necessary to be exactly at the center, and generally at the center is sufficient) of any one of the four side portions forming the outer edge of the main body portion 21 of the pressing member 20. In this case, as shown in FIG. 3, among the four fixing portions 25a to 25d of the pressing member 20, the fixing portion 25a and the fixing portion 25b are arranged to face each other with two switching elements 61 interposed therebetween.

[0028] Furthermore, the pressing member 20 has six (i.e., the same number as the switching elements 61) element pressing portions 27. Each of the six element pressing portions 27 is provided at a portion outside the opening 23 in the main body portion 21 and protrudes downward. The six element pressing portions 27 of the pressing member 20 are configured such that each of the four fixing portions 25a to 25d of the pressing member 20 is fixed to the corresponding pressing member mounting portions 15a to 15d by screws 17, contacts the upper surface of any one of the six switching elements 61, and presses any one of the six switching elements 61 against the element installation portion 79.

[0029] Note that the "pressing member mounting portions 15a to 15d" and the "element pressing portions 27" in the present embodiment correspond to the "mounting portion" and the "pressing portion" of the present invention, respectively. Also, the fixing portion 25a and the fixing portion 25b correspond to the "pair of fixing portions" of the present invention.

[0030] According to the electric compressor 1 according to the embodiment, for example, the following effects can be obtained.

[0031] In the electric compressor 1 according to the embodiment, the plurality (six) of switching elements 61 constituting the inverter 6 are fixed to the element installation portion 79 provided in the inverter housing 7 by the pressing member 20. The element installation portion 79 functions as a heat dissipation portion. The pressing member 20 is made of a metallic material having spring properties, that is, a material having spring properties and good thermal conductivity. Further, the pressing member 20 is disposed between the six switching elements 61 and the circuit board 63, and has four fixing portions 25a to 25d fixed to the four pressing member mounting portions 15a to 15d provided in the inverter housing 7, and six element pressing portions 27 each of which contacts the upper surface of any one of the six switching elements 61 and presses it against the element installation portion 79.

[0032] Since the six switching elements 61 are pressed against the element installation portion 79 that functions as a heat dissipation portion by the six element pressing portions 27 of the pressing member 20, the heat of the six switching elements 61 can be stably dissipated. Further, since the pressing member 20 is formed of a material having good thermal conductivity, the heat of the six switching elements 61 can also be dissipated through the pressing member 20. Therefore, according to the electric compressor 1 according to the embodiment, higher cooling performance for the switching element 61 can be obtained as compared with the prior art.

[0033] Further, the four fixing portions 25a to 25d of the pressing member 20 are arranged at intervals from each other so as to surround the six switching elements 61 on the element installation portion 79. Specifically, the six switching elements 61 are arranged in a rectangular shape as a whole in a plan view on the element installation portion 79, and the pressing member 20 has a rectangular main body portion 21 having a size corresponding to the whole of the six switching elements 61 arranged on the element installation portion 79. An opening 23 for passing the leads 61a of the six switching elements 61 is formed in the main body portion 21. The six element pressing portions 27 are provided on the main body portion 21, and each of the four fixing portions 25a to 25d extends outward from the center of any one of the four sides forming the outer edge of the main body portion 21.

[0034] Therefore, the six switching elements 61 can be stably fixed by the pressing member 20, the four fixing portions 25a to 25d are arranged in a well-balanced manner with respect to the six element pressing portions 27, and the heat of the six switching elements 61 can be stably dissipated through the four fixing portions 25a to 25d.

[0035] Incidentally, in the above-described embodiment, the pressing member 20 has four fixing portions 25a to 25d, and each of the four fixing portions 25a to 25d extends outward from the center of any one of the four side portions forming the outer edge of the main body portion 21. However, the present invention is not limited to this. For example, as shown in FIG. 5, the pressing member 20 may have six fixing portions 25a to 25f (although not shown in FIG. 5, six pressing member mounting portions are of course provided). In this case, as shown in FIG. 5, among the six fixing portions 25a to 25f, the fixing portion 25a and the fixing portion 25b are arranged to face each other with two switching elements 61 forming different columns therebetween, the fixing portion 25c and the fixing portion 25d are arranged to face each other with three switching elements 61 forming one column therebetween, and the fixing portion 25e and the fixing portion 25f may be arranged to face each other with three switching elements 61 forming another column therebetween.

[0036] Also, although not shown, a heat dissipation member (heat dissipation sheet) may be installed on the element installation portion 79, and the six element pressing portions 27 of the pressing member 20 may be configured to press the six switching elements 61 against the element installation portion 79 via the heat dissipation member (heat dissipation sheet).

[0037] As described above, the embodiments and modifications of the present invention have been described. However, the present invention is not limited to the above-described embodiments and modifications, and it goes without saying that further modifications are possible based on the technical idea of the present invention.

Explanation of Reference Numerals

[0038] 1... Electric compressor, 2... Rotating shaft, 3... Electric motor, 4... Compression mechanism, 5... Main body housing, 6... Inverter, 7... Inverter housing, 8... Cover member, 11... Substrate mounting portion, 15a to 15d... Pressing member mounting portions (mounting portions), 20... Pressing member, 21... Main body portion, 23... Opening, 25a to 25f... Fixing portions, 27... Element pressing portion (pressing portion), 61... Switching element, 61a... Lead, 63... Circuit board

Claims

1. An electric compressor having an electric motor that rotates a rotating shaft, a compression mechanism driven by the rotation of the rotating shaft, and an inverter that drives and controls the electric motor, wherein the inverter is housed in an inverter housing, the inverter includes a plurality of switching elements, the plurality of switching elements are fixed to an element installation portion provided in the inverter housing by a pressing member, the pressing member has a plurality of fixing portions fixed to a mounting portion provided in the inverter housing and a plurality of pressing portions each pressing one of the plurality of switching elements against the element installation portion, and is formed of a material having thermal conductivity, an electric compressor.

2. the inverter further includes a circuit board on which the plurality of switching elements are electrically connected and a control circuit for controlling the operation of the plurality of switching elements is mounted, the pressing member is formed of a springy metal material and is disposed between the plurality of switching elements and the circuit board, the electric compressor according to claim 1.

3. the plurality of fixing portions of the pressing member are spaced apart from each other so as to surround the plurality of switching elements in a plan view, the electric compressor according to claim 1 or 2.

4. the plurality of switching elements are arranged in a rectangular shape as a whole on the element installation portion in a plan view, the pressing member is a rectangular main body portion having a size corresponding to the whole of the plurality of switching elements, and has a rectangular main body portion in which at least one opening for passing leads of the plurality of switching elements is formed, the plurality of pressing portions are provided on the main body portion, each of the plurality of fixing portions extends outward from one of four side portions forming the outer edge of the main body portion, the electric compressor according to claim 3.

5. each of the plurality of fixing portions extends outward from the center of one of four side portions forming the outer edge of the main body portion, the electric compressor according to claim 4.

6. the plurality of fixing portions include a pair of fixing portions arranged so as to sandwich at least two of the plurality of switching elements, the electric compressor according to claim 4.

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