Electric compressor

Abstract

In an electric compressor in which the compression mechanism, electric motor, and inverter are arranged in a line, the heat-generating element of the inverter can be suitably cooled with a simple configuration. [Solution] The electric compressor (10) includes a compression mechanism (20) for compressing a fluid, an electric motor (30) for driving the compression mechanism (20), and an inverter (40) for controlling the electric motor (30). The compression mechanism (20), the electric motor (30), and the inverter (40) are arranged in the axial direction of the output shaft (31) of the electric motor (30). An intake port (63) for drawing in low-temperature, low-pressure refrigerant (Re) from the outside is provided on the side (62) of the motor housing (60) that houses the electric motor (30). The electric compressor (10) is equipped with a gas induction means (140) for guiding the refrigerant (Re) drawn in from the intake port (63) to the inverter (40).

Description

Technical Field

[0001] The present invention relates to an electric compressor provided with an inverter used in a refrigeration cycle of an air conditioner, and is capable of preferably cooling a heating element of the inverter.

Background Art

[0002] As a conventional compressor, an electric compressor in which a compression mechanism, an electric motor for driving the compression mechanism, and an inverter for driving and controlling the electric motor are arranged in a row is known. The inverter is provided adjacent to a motor housing through which the suction refrigerant passes via a partition wall, and the inverter is cooled by the low-temperature suction refrigerant. In particular, cooling of the inverter is required when the electric motor operates at a low speed.

[0003] However, the refrigerant sucked from the suction port flows toward the compression mechanism provided on the side opposite to the inverter with respect to the partition wall, so it is difficult to flow toward the inverter side. Furthermore, a boss of a sub-bearing for supporting the output shaft of the electric motor is provided on the partition wall, and cooling by the flow of the sucked refrigerant tends to be insufficient. Therefore, even if the power semiconductor (heating element) of the inverter is attached to the partition wall, there is room for improvement in efficient cooling.

[0004] On the other hand, a technique has been proposed for actively using the refrigerant sucked from the suction port to cool the heating element of the inverter. For example, the technique of Patent Document 1 is known.

[0005] The electric compressor known in Patent Document 1 separates the motor housing and the inverter housing, provides a refrigerant gas chamber between the separated parts, and introduces the refrigerant sucked from the refrigeration cycle into the refrigerant gas chamber. The introduced refrigerant cools the heating element while flowing through the refrigerant gas chamber, and also flows into the motor housing chamber to cool the electric motor.

Prior Art Documents

Patent Documents

[0006] [Patent Document 1] Japanese Patent Publication No. 2009-074517 [Overview of the project] [Problems that the invention aims to solve]

[0007] However, in the structure of the electric compressor known in Patent Document 1, the motor housing and inverter housing must be separate, with a refrigerant gas chamber placed between them, which results in a complex structure and the disadvantage of a long overall length for the electric compressor.

[0008] The present invention has been made to solve the above-mentioned problems, and aims to provide a structure that can suitably cool the heat-generating element of an inverter with a simple configuration in an electric compressor in which a compression mechanism, an electric motor, and an inverter are arranged in a line. [Means for solving the problem]

[0009] In the following description, reference numerals in the accompanying drawings are indicated in parentheses to facilitate understanding of the present invention; however, this does not mean that the present invention is limited to the illustrated forms.

[0010] According to this disclosure, the invention includes a compression mechanism (20) for compressing a fluid, an electric motor (30) for driving the compression mechanism (20), an inverter (40) for controlling the electric motor (30), a motor housing (60) for housing the electric motor (30), and an inverter housing (70) for housing the inverter (40). The compression mechanism (20), the electric motor (30), and the inverter (40) are arranged in the axial direction of the output shaft (31) of the electric motor (30). An electric compressor (10) is provided with an intake port (63) on the side (62) of the motor housing (60) for drawing in a low-temperature, low-pressure refrigerant (Re) from the outside, An electric compressor is provided, which includes a gas induction means (140) that guides the refrigerant (Re) drawn in from the intake port (63) to the inverter (40).

[0011] Preferably, the gas induction means (140) is composed of a wind direction unit (150) that directs the refrigerant (Re) drawn in from the intake port (63) toward the inverter (40), and the wind direction unit (150) is provided on the stator (33) of the electric motor (30).

[0012] More preferably, the stator (33) has a coil cover (130) provided to cover the coil end (115a) that protrudes from the end face (111a) of the stator core (111) toward the inverter (40), and the airflow deflector (150) is provided on the coil cover (130).

[0013] More preferably, when viewing the intake port (63) from the port opening (63a) side, the airflow direction portion (150) overlaps with half of the projected view of the intake port (63).

[0014] More preferably, the airflow section (150) has an arc-shaped airflow surface (151) that is concave from the outer peripheral edge (133) of the coil cover (130) toward the inverter (40) and toward the radial center of the motor housing (60).

[0015] More preferably, the airflow section (150) extends circumferentially along the outer circumference of the coil cover (130) and is located only at the location of the intake port (63). [Effects of the Invention]

[0016] In this invention, in an electric compressor in which a compression mechanism, motor, and inverter are arranged in a line, the heat-generating element of the inverter can be suitably cooled with a simple configuration. [Brief explanation of the drawing]

[0017] [Figure 1] This is a cross-sectional view of the electric compressor according to the embodiment, taken along the motor shaft. [Figure 2] This is a perspective view of the stator shown in FIG. 1. [Figure 3] This is an enlarged view of part 3 in FIG. 1. [Figure 4] This is a cross-sectional view taken along line 4-4 in FIG. 3. [Figure 5] This is a cross-sectional view taken along line 5-5 in FIG. 1, with the cluster block and relay terminal omitted. [Figure 6] This is a view of arrow 6 in FIG. 4.

Embodiments for Carrying Out the Invention

[0018] Embodiments of the present invention will be described below based on the accompanying drawings. Note that the embodiments shown in the accompanying drawings are examples of the present invention, and the present invention is not limited to these embodiments.

[0019] <Example> As shown in FIG. 1, the electric compressor 10 has a configuration of a so-called horizontally installed electric compressor that can be installed horizontally, for example. This electric compressor 10 includes a compression mechanism 20 that compresses a fluid (refrigerant gas), an electric motor 30 that drives this compression mechanism 20, and an inverter 40 that controls this electric motor 30. Further, the electric compressor 10 includes a compression housing 50 having a compression housing chamber 51 that houses the compression mechanism 20, a motor housing 60 having a motor housing chamber 61 that houses the electric motor 30, and an inverter housing 70 having an inverter housing chamber 71 that houses the inverter 40.

[0020] First, each housing 50 to 70 will be described. As shown in Figure 1, the compression housing 50, motor housing 60, and inverter housing 70 are made of a metal material such as aluminum and are arranged in the axial direction of the output shaft 31 of the electric motor 30 (along the center line CL of the output shaft 31). These three housings 50 to 70 may all be a single integrated unit as shown in Figure 1, or they may all be separate units, or only two of them may be integrated.

[0021] The compressor housing 51 and the motor housing 61 are separated by a partition member 80. The end of the compression housing 50 opposite to the motor housing 60 is fully open and closed by an openable and closable head member 90. The head member 90 has a discharge chamber 91 for discharging the compressed refrigerant Re from the compression chamber 23 of the compression mechanism 20, an oil separator 92 for separating oil from the compressed refrigerant Re, and a discharge port 93 for discharging the gaseous refrigerant Re from which the oil has been separated to the outside.

[0022] An intake port 63 is provided on the side surface 62 (outer circumferential surface 62) of the motor housing 60 for drawing in low-temperature, low-pressure refrigerant Re from the outside into the motor housing chamber 61. It is preferable that this intake port 63 be set as close as possible to the inverter housing chamber 71. The space between the motor housing chamber 61 and the inverter housing chamber 71 is closed by a partition wall 100. This partition wall 100 may be an integral part of the motor housing 60 and the inverter housing 70, as shown in Figure 1, or it may be a separate component. The end of the inverter housing 70 opposite to the motor housing 60 is completely open and closed by an openable and closable cover 72.

[0023] Next, the compression mechanism 20 will be described. The compression mechanism 20 compresses the refrigerant Re (refrigerant gas Re) drawn into the compression housing 50 from the refrigeration cycle of an air conditioning system (not shown) via the motor housing 60, and is composed of, for example, a scroll compression mechanism. This compression mechanism 20 compresses the refrigerant Re by combining a fixed scroll 21 positioned in the compressor housing chamber 51 with its relative rotation restricted, and an orbiting scroll 22 that can swing circumferentially relative to the fixed scroll 21.

[0024] Next, we will explain the electric motor 30. The electric motor 30 is configured as, for example, a three-phase AC brushless motor. This electric motor 30 comprises an output shaft 31 (motor shaft 31), a rotor 32 fixed to the output shaft 31, and a cylindrical stator 33 surrounding the rotor 32. The outer circumferential surface of the stator 33 is fixed to the inner circumferential surface of the motor housing 60 by a shrink fit or similar interference fit. The output shaft 31 is rotatably supported by a first bearing 34 provided on the partition member 80 and a second bearing 35 provided on the partition wall 100. The partition wall 100 integrally includes a boss 101 into which the second bearing 35 is fitted. This boss 101 extends from the partition wall 100 to the motor housing chamber 61.

[0025] As the output shaft 31 of the electric motor 30 rotates, the oscillating scroll 22 revolves. The refrigerant Re drawn in from the intake port 63 of the motor housing 60 passes through the gap of the electric motor 30 in the motor housing chamber 61, cooling the heat generated by the electric motor 30, and is taken into the compression chamber 23 of the compression mechanism 20. As the oscillating scroll 22 revolves, the compression chamber 23 gradually moves toward the center while its internal volume decreases. As a result, the refrigerant Re in the compression chamber 23 is compressed. When the pressure in the compression chamber 23 rises to the point where it exceeds the pressure required to open the discharge valve 24, the discharge valve 24 opens due to the pressure difference. The refrigerant Re in the compression chamber 23 flows into the discharge chamber 91 through the discharge hole 25. The refrigerant Re in the discharge chamber 91 is discharged outward from the discharge port 93 via the oil separator 92.

[0026] Next, we will explain the stator 33 of the electric motor 30 in detail. As shown in Figures 1 to 3, the stator 33 comprises an annular stator core 111, first and second insulators 112 and 113, and a plurality of conductors 114. The stator core 111 has a laminated structure of ferromagnetic plates and has an annular back yoke and a plurality of teeth that protrude from the inner circumferential surface of the back yoke toward the center line CL of the stator core 111 (the center line CL of the output shaft 31).

[0027] When the stator core 111 is viewed along the center line CL, the first and second insulators 112 and 113 are configured in an annular shape similar to that of the stator core 111. These insulators 112 and 113 are made of molded products of electrically insulating resin. The first insulator 112 is provided on the end face 111a (first end face 111a) of the stator core 111 on the partition wall 100 side. The second insulator 113 is provided on the end face 111b (second end face 111b) of the stator core 111 on the partition member 80 side.

[0028] The coil 115 of the conductor 114 is wound around the stator core 111 and each insulator 112, 113. Of the coil 115, the portion 115a (first coil end 115a) wound around the first insulator 112 protrudes from the first end face 111a of the stator core 111 toward the inverter 40. Of the coil 115, the portion 115b (second coil end 115b) wound around the second insulator 113 protrudes from the second end face 111b of the stator core 111 toward the compression mechanism 20.

[0029] The lead wires 116 (see Figure 2) drawn out from the beginning and end of the coil 115 are connected to the printed circuit board 42 of the inverter 40 by the cluster block 121 (electrical connector 121) and the relay terminal 122.

[0030] Furthermore, the stator 33 is equipped with a coil cover 130 attached to the first insulator 112. This coil cover 130 is made of electrically insulating resin and covers the first coil end 115a, jumper wires (not shown), and lead wires 116. Therefore, the first coil end 115a, jumper wires (not shown), and lead wires 116 can be easily protected simply by attaching the coil cover 130 to the first insulator 112 on which the first coil end 115a is located.

[0031] More specifically, the coil cover 130 is composed of a cylindrical body 131 and an annular top plate 132. The cylindrical body 131 covers the outer circumferential surface of the first insulator 112 and the outer circumferential surface of the first coil end 115a. The outer diameter of the cylindrical body 131 is slightly smaller than the outer diameter of the stator 33. Therefore, with the outer circumferential surface of the stator 33 fixed to the inner circumferential surface of the motor housing 60, the outer circumferential surface of the cylindrical body 131 does not come into contact with the inner circumferential surface of the motor housing 60. The top plate 132 is a flat plate that extends radially inward from the edge 133 on the inverter 40 side of the cylindrical body 131, and is perpendicular to the center line CL of the stator core 111. This top plate 132 covers at least a portion of the end face of the first insulator 112 on the inverter 40 side and at least a portion of the first coil end 115a. The edge 133 of the cylindrical body 131 on the inverter 40 side is sometimes referred to as the "outer peripheral edge 133 of the coil cover 130."

[0032] Next, we will explain inverter 40 in detail. As shown in Figures 1 and 3, the inverter 40 includes an active motor drive element 41 (active element 41), such as a switching element (power semiconductor element), which controls the drive of the electric motor 30, and a printed circuit board 42 on which this motor drive element 41 can be mounted. An example of a switching element is an IGBT (Insulated Gate Bipolar Transistor). Since the motor drive element 41 carries a larger current than passive elements such as resistors, it generates a large amount of heat during operation, and it is preferable to actively dissipate the heat. This motor drive element 41 is sometimes called a "heat-generating element 41".

[0033] Of the partition wall 100, the side 102 on the inverter housing chamber 71 side is called the "inverter 40 side partition wall surface 102" or "first surface 102," and the side 103 on the motor housing chamber 61 side is called the "electric motor 30 side partition wall surface 103" or "second surface 103." The partition wall 100 has a flat element stacking surface 104 on a part of the partition wall surface 102 on the inverter 40 side. The motor drive elements 41 are superimposed on the element stacking surface 104.

[0034] As shown in Figures 3 and 4, the electric compressor 10 of this embodiment is equipped with a gas induction means 140 that guides the refrigerant Re drawn in from the intake port 63 toward the inverter 40 (the element stacking surface 104 side) in order to enhance the effect of cooling the inverter 40 (especially the motor drive element 41) by actively utilizing the refrigerant Re drawn in from the intake port 63.

[0035] This gas induction means 140 is composed of an airflow deflector 150 that directs the refrigerant Re drawn in from the intake port 63 toward the inverter 40. This airflow deflector 150 is provided on the top plate 132 inside the coil cover 130 of the stator 33, and is preferably a resin molded product formed integrally with the top plate 132.

[0036] As shown in Figures 3 to 5, the airflow section 150 has an airflow surface 151 that guides the refrigerant Re drawn in from the intake port 63. This airflow surface 150 is inclined from the outer peripheral edge 133 of the coil cover 130 toward the inverter 40 side and toward the radial center of the motor housing 60 (center line CL of the stator core 111). Therefore, the refrigerant Re drawn in from the intake port 63 can be directed toward the inverter 40 side along the airflow surface 151.

[0037] More specifically, this airflow surface 151 guides the refrigerant Re drawn in from the intake port 63 toward the portion 105 (element placement portion 105) of the partition wall surface 103 on the electric motor 30 side of the partition wall 100 where the motor drive element 41 is located. This element placement portion 105 is located on the opposite side of the partition wall 100 from the element stacking surface 104.

[0038] The base end 152 of the airflow surface 151 is located on the outer peripheral edge 133 of the coil cover 130 and is formed in an arc shape along this outer peripheral edge 133. The tip 153 of the airflow surface 151 is located on the partition wall 100 side of the coil cover 130 and is formed in an arc shape along the inner peripheral edge 134 of the coil cover 130 (the inner peripheral edge 134 of the top plate 132). Since the tip 153 of the airflow surface 151 is away from the partition wall surface 103 on the electric motor 30 side of the partition wall 100, the flow resistance of the refrigerant Re can be suppressed.

[0039] The airflow surface 151 is preferably an arc-shaped surface that is concave from the outer peripheral edge 133 of the coil cover 130 toward the inverter 40 side and toward the radial center of the motor housing 60. In other words, the airflow surface 151 is concave toward the opposite side of the port opening 63a of the intake port 63 with respect to the straight line 154 (see Figure 3) passing through the base end 152 and the tip end 153.

[0040] The circumferential ends of the wind deflector 150 are integrated with the top plate 132 by reinforcing ribs 155 (see Figure 3). This allows for increased rigidity of the wind deflector 150.

[0041] As shown in Figures 4 and 6, the airflow section 150 extends circumferentially along the outer circumference 133 (outer edge 133) of the coil cover 130 and is located only at the intake port 63.

[0042] When viewing the intake port 63 from the port opening 63a side, the airflow direction section 150 overlaps with half of the projected area of ​​the intake port 63. For example, as shown in Figure 6, the area A2 (represented by dashed lines) where the port opening 63a and the airflow direction surface 151 overlap is half the area A1 of the port opening 63a. This makes it possible to achieve both suppression of the flow resistance of the refrigerant Re and improvement of the cooling effect of the motor drive element 41 (heat-generating element 41).

[0043] As shown in Figures 3 and 5, the refrigerant Re drawn in from the intake port 63 is guided by the airflow surface 151 toward the partition wall surface 103 (particularly the element placement area 105) on the electric motor 30 side. The heat generated by the motor drive element 41 is transferred from the element stacking surface 104 through the element placement area 105 of the partition wall 100 to the low-temperature refrigerant Re (refrigerant gas Re) flowing inside the motor housing 60 (motor storage chamber 61), and heat exchange is efficiently performed.

[0044] As shown in Figure 5, the airflow deflector 150 may extend circumferentially along the outer circumference of the coil cover 130, and may, for example, be located around the entire circumference of the coil cover 130.

[0045] To summarize the above explanation, it is as follows:

[0046] Refer to Figure 1. The electric compressor 10 includes a compression mechanism 20 for compressing a fluid, an electric motor 30 for driving the compression mechanism 20, an inverter 40 for controlling the electric motor 30, a motor housing 60 for housing the electric motor 30, and an inverter housing 70 for housing the inverter 40. The compression mechanism 20, the electric motor 30, and the inverter 40 are arranged in the axial direction of the output shaft 31 of the electric motor 30. An intake port 63 for drawing in low-temperature, low-pressure refrigerant Re from the outside is provided on the side 62 of the motor housing 60. Furthermore, the electric compressor 10 is equipped with a gas induction means 140 for guiding the refrigerant Re drawn in from the intake port 63 to the inverter 40.

[0047] Therefore, the refrigerant Re drawn in from the intake port 63 on the side 62 of the motor housing 60 can be actively guided to the inverter 40 by the gas induction means 140. Consequently, there is no need to provide a refrigerant gas chamber between the motor housing 60 and the inverter housing 70 for the refrigerant Re drawn in from the intake port 63. Since there is no refrigerant gas chamber, the overall length of the electric compressor 10 can be kept short, and the heat-generating element 41 (motor drive element 41) of the inverter 40 can be cooled suitably with a simple configuration.

[0048] Refer to Figure 1. The gas induction means 140 is composed of a wind direction unit 150 that directs the refrigerant Re drawn in from the intake port 63 toward the inverter 40. This wind direction unit 150 is provided on the stator 33 of the electric motor 30. Thus, the gas induction means 140 is simply composed of a wind direction unit 150 provided on the stator 33, resulting in a simple configuration.

[0049] Refer to Figure 3. The stator 33 has a coil cover 130 that covers the coil end 115a (first coil end 115a) that protrudes from the end face 111a (end face 111a on the bulkhead 100 side) of the stator core 111 toward the inverter 40 side. The air direction section 150 is provided on the coil cover 130.

[0050] Therefore, the airflow section 150 that constitutes the gas induction means 140 only needs to be provided on the coil cover 130. No separate component is required to provide the gas induction means 140, thus preventing an increase in the number of parts. Moreover, on the coil cover 130 closer to the inverter 40, it is easy to position the airflow section 150 in accordance with the position of the intake port 63 provided on the motor housing 60, thereby increasing the design flexibility.

[0051] Refer to Figures 4 and 6. When viewing the intake port 63 from the port opening 63a side, the airflow direction section 150 overlaps with half of the projected area of ​​the intake port 63. Since the airflow direction section 150 overlaps with only half of the projected area of ​​the intake port 63, it is possible to suppress the flow resistance of the refrigerant Re drawn in from the intake port 63 while ensuring a cooling effect to cool the heat-generating element 41 (motor drive element 41) of the inverter 40.

[0052] Refer to Figure 3. The airflow section 150 has an arc-shaped airflow surface 151 that is concave from the outer peripheral edge 133 of the coil cover 130 toward the inverter 40 side and toward the radial center of the motor housing 60.

[0053] The refrigerant Re drawn in through the intake port 63 located on the side surface 62 of the motor housing 60 basically flows towards the vicinity of the outer edge 133 of the coil cover 130. The airflow surface 151 of the airflow section 150 is an arc shape that is concave from the outer edge 133 of the coil cover 130 toward the inverter 40 and toward the radial center of the motor housing 60. Therefore, the refrigerant Re can be smoothly directed toward the inverter 40 along the airflow surface 151, thereby efficiently cooling the heat-generating elements 41 (motor drive elements 41) of the inverter 40.

[0054] Refer to Figure 4. The airflow section 150 extends circumferentially along the outer circumference of the coil cover 130 and is located only at the intake port 63. This makes it possible to further achieve both the suppression of flow resistance of the refrigerant Re drawn in from the intake port 63 and the cooling efficiency of the heat-generating element 41 (motor drive element 41) of the inverter 40.

[0055] Furthermore, the present invention is not limited to the embodiments, provided that it achieves the functions and effects of the present invention. [Industrial applicability]

[0056] The electric compressor 10 of the present invention is suitable for use in the refrigeration cycle of a vehicle air conditioning system. [Explanation of symbols]

[0057] 10...Electric compressor, 20...Compression mechanism, 30...Electric motor, 31...Output shaft, 32...Rotor, 33...Stator, 40...Inverter, 41...Motor drive element, 60...Motor housing, 62...Side (outer surface), 63...Intake port, 63a...Port opening, 70...Inverter housing, 111...Stator core, 111a...End face (end face on the partition wall side), 115a...Coil end (first coil end), 130...Coil cover, 140...Gas induction means, 150...Air direction section, 151...Air direction surface, CL...Centerline of the stator core, A1...Area of ​​the port opening, A2...Area where the port opening and the air direction surface overlap, Re...Refrigerant.

Claims

1. It includes a compression mechanism (20) for compressing a fluid, an electric motor (30) for driving the compression mechanism (20), an inverter (40) for controlling the electric motor (30), a motor housing (60) for housing the electric motor (30), and an inverter housing (70) for housing the inverter (40), The compression mechanism (20), the electric motor (30), and the inverter (40) are arranged in the axial direction of the output shaft (31) of the electric motor (30). An electric compressor (10) is provided with an intake port (63) on the side (62) of the motor housing (60) for drawing in a low-temperature, low-pressure refrigerant (Re) from the outside, An electric compressor equipped with a gas induction means (140) that guides the refrigerant (Re) drawn in from the intake port (63) to the inverter (40).

2. The gas induction means (140) is configured with an airflow section (150) that directs the refrigerant (Re) drawn in from the intake port (63) toward the inverter (40). The electric compressor according to claim 1, wherein the airflow section (150) is provided on the stator (33) of the electric motor (30).

3. The stator (33) has a coil cover (130) provided to cover the coil end (115a) that protrudes from the end face (111a) of the stator core (111) toward the inverter (40). The electric compressor according to claim 2, wherein the airflow section (150) is provided on the coil cover (130).

4. The electric compressor according to claim 3, wherein, when the intake port (63) is viewed from the port opening (63a) side, the air direction portion (150) overlaps with half of the projected portion of the intake port (63).

5. The electric compressor according to claim 3 or 4, wherein the airflow section (150) has an arc-shaped airflow surface (151) that is concave from the outer peripheral edge (133) of the coil cover (130) toward the inverter (40) side and toward the radial center side of the motor housing (60).

6. The electric compressor according to claim 3, wherein the airflow section (150) extends circumferentially along the outer circumference of the coil cover (130) and is located only at the location of the intake port (63).

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