Electric compressor

Abstract

An electric compressor (1) comprises: a housing (2) having a suction port (109) and a discharge port (263) of a working medium; a drive shaft (105); a motor (102) for rotating the drive shaft; and a scroll compression mechanism (204) having a swing scroll (220) attached to one end of the drive shaft and driven by the drive shaft, and a fixed scroll (210). An oil pump (140) attached to the other end of the drive shaft and driven by the drive shaft supplies oil sucked from an oil storage space (108) at the lower part of a motor chamber (101) to a portion to be lubricated via an oil supply passage (144) provided inside the drive shaft (105). Oil contained in the working medium compressed by the scroll compression mechanism (204) is separated by an oil separator (261) and returned to the oil storage space (108) via an oil return passage (280).

Description

Electric compressor

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

[0002] Patent Document 1 (JP 2-27186 A) describes a conventional horizontal scroll compressor. This compressor uses an oil pump installed at the end of the rotating shaft opposite the scroll compression mechanism to draw oil from an oil reservoir within the shell and supply it to bearing sliding parts, etc. The oil that lubricates the bearing sliding parts, etc., is returned to the oil reservoir. In the compressor of Patent Document 1, an oil flow path and oil reservoir are installed at the bottom of the shell, while a refrigerant gas flow path is installed at the top end of the shell. In other words, by substantially separating the liquid oil flow path and the refrigerant gas flow path, oil is prevented from being sucked into the compression chamber of the scroll compression mechanism along with the refrigerant gas. Patent Document 1 also describes that almost no oil flows into the compression chamber.

[0003] However, if almost no oil flows into the compression chamber as described above, there is a concern that the sliding and rolling parts of the fixed scroll and orbiting scroll may be damaged due to insufficient lubrication.

[0004] Furthermore, if almost no oil flows into the compression chamber as described above, it is not possible to ensure airtightness of the compression chamber due to oil, which raises concerns that the compression efficiency of the compressor may decrease.

[0005] To address these concerns, a configuration can be adopted that allows a sufficient amount of oil to be supplied to the compression chamber, such as a configuration that supplies the compression chamber with the refrigerant gas in an amount necessary for lubrication. For example, a configuration can be considered in which the refrigerant gas intake port of the compression chamber is also provided in the lower region of the shell. When a sufficient amount of oil is supplied to the compression chamber, the oil is discharged from the compression chamber together with the compressed refrigerant gas and flows into the refrigeration cycle outside the compressor. The oil that flows into the refrigeration cycle circulates through the refrigeration cycle and then returns to the compressor through the suction port.

[0006] During low-load operation of the refrigeration cycle, oil leaking from the compressor has difficulty returning to the compressor, which reduces the amount of oil in the shell's oil sump and can lead to poor lubrication within the compressor. In refrigeration cycles used in bus air conditioners and refrigerated vehicles, the compressor is often located near the engine at the bottom of the vehicle, and the heat exchanger is often located above the vehicle, such as on the roof, resulting in a long total length of piping for the refrigeration cycle. In this case, it becomes even more difficult for oil leaking from the compressor to return to the compressor, making the above-mentioned problems more likely to occur.

[0007] In the device of Patent Document 1, even if a sufficient amount of oil were supplied to the compression chamber, the same problems as those described above would still occur.

[0008] The horizontal scroll compressor disclosed in Patent Document 2 (JP 2014-145353 A) has an oil separator installed in the compressor shell (housing) to minimize the amount of oil contained in the working medium flowing from the compressor to the refrigeration cycle. In the compressor of Patent Document 2, the oil separated from the working medium by the oil separator is returned to the space near the orbiting scroll in the motor chamber through a through-hole formed inside the wall of the fixed scroll. This returned oil is used to lubricate the scroll compression mechanism, the motor, and the sliding parts around it. The configuration of Patent Document 2 eliminates the problem of oil leaking from the compressor to the refrigeration cycle piping not being sufficiently returned. Here, the term "working medium" refers to the medium circulating within the refrigeration cycle, including the compressor, and includes refrigerant and oil.

[0009] However, the temperature of the working medium discharged from the scroll compression mechanism during operation is high. Therefore, the temperature of the oil returning via the above-mentioned route is also high. Supplying high-temperature, low-viscosity oil to bearing sliding parts, etc., can result in poor lubrication. Furthermore, supplying high-temperature oil to the scroll compression mechanism can prevent a sufficient amount of working medium from being supplied to the scroll compression mechanism, potentially reducing compression efficiency.

[0010] An object of the present invention is to provide an electric compressor that can reliably and appropriately lubricate parts to be lubricated.

[0011] According to one embodiment of the present invention, there is provided an electric compressor comprising: a housing having a suction port and a discharge port for a working medium; a drive shaft rotatably supported in a motor chamber within the housing; a motor housed in the motor chamber within the housing and rotating the drive shaft; a scroll compression mechanism including: a fixed scroll fixed to the housing; and an orbiting scroll attached to one end of the drive shaft and driven by the drive shaft; an oil pump attached to the other end of the drive shaft and driven by the drive shaft, the oil pump sucking oil from an oil storage space provided below the motor chamber and supplying it to parts of the scroll compression mechanism to be lubricated via an oil supply passage provided inside the drive shaft; and an oil separator provided within the housing and separating oil contained in the working medium compressed by the scroll compression mechanism from the working medium, and an oil return passage provided within the housing for returning the oil separated by the oil separator to the oil storage space in the motor chamber.

[0012] According to the above embodiment, it is possible to reliably and appropriately lubricate the parts to be lubricated.

[0013] The present invention relates to an electric compressor, and more particularly to an electric motor having a scroll compression mechanism, a motor chamber, a partition wall, a balance weight, and a balance weight arranged in a direction parallel to the scroll compression mechanism.

[0014] An embodiment of the present invention will be described below with reference to the accompanying drawings.

[0015] As shown in Fig. 1, the electric compressor 1 includes a housing 2. In the illustrated embodiment, the housing 2 is mainly formed of a central motor block 100, a compression / discharge block 200 on the left side of the motor block 100, an electric block 300 on the right side of the motor block 100, and a cover block 400 that closes the open end on the right side of the electric block 300. Each of the blocks 100, 200, 300, and 400 is, for example, a die-cast product made of an aluminum alloy.

[0016] Adjacent blocks are butted together via sealing members (not shown) as needed, and are firmly fastened together with screws (not shown). It goes without saying that appropriate sealing members are provided between adjacent components that require sealing, not just between adjacent blocks, as needed, and that the necessary surface pressure for sealing is ensured between the contacting surfaces of the components by means of fastening with screws, for example. Note that such seals are not necessarily shown, and that many fastening means are not shown.

[0017] A motor chamber (motor housing space) 101 is formed inside the motor block 100 to house a motor 102. The motor 102 has a stator 103 and a rotor 104. The rotor 104 has a plurality of permanent magnets (details not shown) embedded therein and is fixed to a drive shaft (rotating shaft) 105.

[0018] The drive shaft 105 is supported by the housing 2 (the motor block 100 in the illustrated example) so as to be rotatable about a horizontally extending axis of rotation via bearings (rolling bearings) 106 and 107. The stator 103 is supplied with power by an inverter drive circuit 302 provided inside the electric block 300, which causes the rotor 104 to rotate.

[0019] The lower part of the motor chamber 101 is an oil storage space 108 in which lubricating oil is stored.

[0020] An intake port 109 is provided in an upper portion of the housing 2 (an upper portion of the motor block 100 in the illustrated example) for taking the working medium compressed by the electric compressor 1 into the housing 2. The intake port 109 is located in an upper portion of the motor chamber 101 and opens to a space on the electric block 300 side of the motor 102.

[0021] The working medium drawn into the compressor contains a very small amount of oil mist in addition to the refrigerant.

[0022] The compression and discharge block 200 includes a scroll chamber (scroll accommodating space) 202 , a discharge chamber 240 , and an oil separation chamber 260 .

[0023] A scroll compression mechanism 204 is provided in the scroll chamber 202. The scroll compression mechanism 204 has a fixed scroll 210 fixed to the housing 2 (the compression discharge block 200 in the illustrated example) and an orbiting scroll 220 disposed at one end of the drive shaft 105 and driven by the motor 102.

[0024] The fixed scroll 210 has an end plate 211, a cylindrical outer wall 212 extending from the outer peripheral edge of the end plate 211 toward the oscillating scroll 220, and a spiral wall 213 extending from the end plate 211 toward the oscillating scroll 220 radially inside the outer peripheral wall 212.

[0025] The orbiting scroll 220 has an end plate 221 and a spiral wall 222 that stands from the end plate 221 toward the fixed scroll 210 .

[0026] One end of an eccentric pin 110 is press-fitted into a position offset from the center of rotation of the drive shaft 105. A balance weight 111 is attached to the eccentric pin 110. The balance weight 111 has a cylindrical journal portion 112 and a weight portion 113. The other end of the eccentric pin 110 is fitted into a hole formed in the journal portion 112. Therefore, as the drive shaft 105 rotates, the balance weight 111 performs eccentric rotation around the center of rotation of the drive shaft 105, thereby reducing vibrations that occur due to the swinging motion of the swing scroll 220.

[0027] The outer peripheral surface of the journal portion 112 is fitted into an inner race of a bearing (rolling bearing) 124. The outer race of the bearing 124 is fitted into a cylindrical bearing support 224 that rises from an end plate 221 of the orbiting scroll 220 toward the drive shaft 105.

[0028] The end plate 221 of the orbiting scroll 220 is provided with a plurality of (e.g., eight) cylindrical recesses surrounding the periphery of the bearing support 224, and a cylindrical ring 225 made of a bearing material is press-fitted into each recess. A plurality of (e.g., eight) pins 226 are press-fitted into the wall (partition wall) 118 of the motor block 100 adjacent to the scroll compression mechanism 204. Each ring 225 houses one pin 226. The outer diameter of the pins 226 is smaller than the inner diameter of the rings 225.

[0029] Due to the presence of the bearing 124 and the cooperative action of the ring 225 and the anti-rotation pin 226, the orbiting scroll 220 can only revolve (oscillate), but cannot rotate. This type of so-called "pin and ring" type anti-rotation mechanism is well known as an anti-rotation mechanism in a scroll compression mechanism, so detailed illustrations and explanations will be omitted. Note that instead of the above-mentioned pin and ring type anti-rotation mechanism, an anti-rotation mechanism using an Oldham ring may be used.

[0030] A wall of the housing 2 (in the illustrated example, the wall of the motor block 100, i.e., the partition wall 118) that separates the motor chamber 101 and the scroll chamber 202 has a plurality of (e.g., six) through holes 130 (hereinafter referred to as "working medium supply holes 130") formed therein (see Figure 2).

[0031] A plurality of (e.g., six) working medium supply holes 130 are provided at equal intervals in the circumferential direction at positions slightly inside the cylindrical outer peripheral wall 212 of the fixed scroll 210. The working medium supply holes 130 are provided so that the working medium is introduced into the outermost peripheral portion of the compression chamber 206 formed between the spiral wall 213 of the fixed scroll 210 and the spiral wall 222 of the orbiting scroll 220.

[0032] The working medium supply hole 130 is provided at a position higher than the oil level L (see L in FIG. 2 ) in the motor chamber 101 during normal operation of the electric compressor 1 so that oil in the oil storage space 108 at the bottom of the motor chamber 101 (particularly high-temperature oil in the oil storage space 108 near the scroll compression mechanism 204) does not directly flow into the scroll compression mechanism 204. In other words, the working medium supply hole 130 is not provided at a position lower than the oil level L.

[0033] The working medium introduced into the motor chamber 101 through the suction port 109 passes through the gap between the outer wall of the motor block 100 and the stator 103, the gap within the stator 103, the gap between the stator 103 and the rotor 104, etc., and flows through the motor chamber 101 toward the compression and discharge block 200, and then flows into the scroll compression mechanism 204 through the working medium supply hole 130.

[0034] In other words, the motor chamber 101 is provided in a low-pressure region where a working medium with a relatively low pressure and low temperature drawn in from the suction port 109 flows, and is provided in a space upstream of the scroll compression mechanism 204 .

[0035] During normal operation of the electric compressor 1, oil in the oil storage space 108 at the bottom of the motor chamber 101 is stirred up as the rotor 104 rotates, and turns into mist that floats inside the motor chamber 101. This oil mist flows with the flow of the working medium into the scroll compression mechanism 204, where it seals and lubricates the contact portions between the fixed scroll 210 and the orbiting scroll 220 that move relative to each other.

[0036] During normal operation of the electric compressor 1, the working medium introduced into the outermost peripheral portion of the compression chamber 206 is compressed as it moves toward the center of the scroll as the orbiting scroll 220 orbits. This compressed working medium flows into the discharge chamber 240 through one or more discharge holes 214 (one in the illustrated example) provided in the approximate center of the end plate 211 of the fixed scroll 210. A check valve 215 made of an elastic metal plate is attached to the end plate 211. The check valve 215 opens the discharge hole 214 only when the pressure in the compression chamber 206 at the position corresponding to the discharge hole 214 is high, and closes the discharge hole 214 when the pressure is low.

[0037] The working medium that flows into the discharge chamber 240 flows out into the oil separation chamber 260 through a through hole 241 formed in the wall of the housing 2 that separates the discharge chamber 240 and the oil separation chamber 260 (in the illustrated example, the wall of the compression discharge block 200).

[0038] The oil separation chamber 260 is provided with an oil separation structure (oil separator) 261. In the illustrated embodiment, the oil separation structure 261 has a cylindrical member 262. The working medium that has flowed into the oil separation chamber 260 from the through-hole 241 flows at a high flow rate in a swirling manner around the cylindrical member 262, and at this time, the oil mist contained in the working medium is centrifuged.

[0039] The working medium from which the oil has been separated flows through the inside of the cylindrical member 262 to the discharge port 263 that opens at the top of the oil separation structure 261, and from there it is discharged into a piping system (including a heat exchanger, etc. that constitutes the refrigeration cycle) connected to the electric compressor 1.

[0040] The position where the oil separation structure 261 is provided is not limited to the position shown in Figure 1, but can be provided at any position on the flow path of the working medium from the discharge hole 214 of the fixed scroll 210 to the discharge port 263 of the housing 2 (compression discharge block 200).

[0041] In other words, the oil separation structure 261 can be provided at any position downstream of the scroll compression mechanism 204 in the high-pressure region where a working medium with a relatively high pressure and high temperature flows.

[0042] The oil separated from the working medium flows down along the inner wall surface of the oil separation chamber 260 and falls into an oil storage space 264 provided at the bottom of the oil separation chamber 260 .

[0043] The oil storage space 264 of the oil separation chamber 260 is connected to the oil storage space 108 of the motor chamber 101 via an oil return passage 280 .

[0044] In the illustrated embodiment, the oil return passage 280 is composed of the following elements: (First element) A horizontal hole 281 drilled in the wall of the compression / discharge block 200, extending horizontally from the oil storage space 264 toward the end plate 211 of the fixed scroll 210; (Second element) A diagonal hole 282 drilled in the end plate 211 of the fixed scroll 210, extending diagonally; (Third element) A horizontal hole 283 drilled in the outer peripheral wall 212 of the fixed scroll 210, extending horizontally; (Fourth element) A vertical groove 284 formed in the end face of the wall of the motor block 100 facing the fixed scroll 210; and (Fifth element) A horizontal hole 285 drilled in the wall of the motor block 100 facing the fixed scroll 210, extending horizontally, and terminating in an oil return hole 286 that opens into the oil storage space 108.

[0045] The oil return passage 280 is provided with a pressure reducing mechanism using an orifice member (not shown) for narrowing the hole diameter (oil flow passage area).

[0046] For example, an orifice member as a pressure reducing mechanism can be provided in the horizontal hole 283, and by using an orifice member with a precisely machined inner diameter, the pressure of the oil flowing from the oil separation chamber 260 in the high-pressure region through the oil return passage 280 into the motor chamber 101 in the low-pressure region can be precisely limited.

[0047] A filter 287 for removing foreign matter contained in the oil is provided on the upstream side of the orifice member, for example, at the entrance of the horizontal hole 281 .

[0048] The oil is prevented from leaking from the oil return passage 280 between the oil storage space 264 of the oil separation chamber 260 and the oil storage space 108 of the motor chamber 101. Specifically, appropriate sealing is provided using a sealing member such as a sheet gasket or an O-ring as needed. Such sealing members may be provided, for example, between the end plate 211 of the fixed scroll 210 and the wall of the compression / discharge block 200, and between the tip of the outer circumferential wall 212 of the fixed scroll 210 and the wall of the motor block 100.

[0049] The path of the oil return passage 280 that connects the oil storage space 264 of the oil separation chamber 260 and the oil storage space 108 of the motor chamber 101 is not limited to that shown in the figure. For example, the oil return passage 280 does not have to pass through the interior of the wall (end plate 211, outer peripheral wall 212) of the fixed scroll 210, and may pass through, for example, the wall of the compression / discharge block 200 below the fixed scroll 210.

[0050] Next, lubrication of the parts around the drive shaft 105 will be described.

[0051] An oil pump 140 driven by the drive shaft 105 is attached to the end of the drive shaft 105 opposite the scroll compression mechanism 204. The oil pump 140 may be, for example, a trochoid oil pump, but is not limited to this. The oil pump 140 is shown in a simplified form in FIG. 1 .

[0052] An oil suction hole 142 is provided in the oil storage space 108 of the motor chamber 101. This oil suction hole 142 is provided at a height position that is always lower than the oil level L in the oil storage space 108 during normal operation of the electric compressor 1.

[0053] Oil is sucked from the oil suction hole 142 through an oil suction passage 143 into the oil pump 140. The oil suction passage 143 is, for example, a metal pipe connected to the suction port of the oil pump 140. Alternatively, at least a portion of the oil suction passage 143 may be formed by a hole drilled in the wall of the motor block 100.

[0054] The discharge port of the oil pump 140 is connected to an oil passage (oil supply passage) 144 drilled in the drive shaft 105. The oil passage 144 supplies oil to parts that require lubrication between rolling or sliding members as the drive shaft 105 rotates.

[0055] A first branch passage 145 branches off from the oil passage (main oil passage) 144, and oil is supplied from this first branch passage 145 to a space 146 facing one end of the bearing 107. The oil flows through the bearing 107 to lubricate it, and then drops from the other end of the bearing 107 into the oil storage space 108.

[0056] Between the bearing 106 and the bearing 124, a cavity 150 is formed in the wall of the motor block 100 on the scroll compression mechanism 204 side to allow rotational movement of the weight portion 113 of the balance weight 111.

[0057] A second branch path 147 branches off from the oil passage 144, and oil is supplied from this second branch path 147 to the space between the bearing 106 and the weight portion 113 of the balance weight 111 (part of the cavity 150). Some of this oil flows into the bearing 106 to lubricate it, and then drops into the oil storage space 108 from the end of the bearing 106 opposite the balance weight 111. The remainder of the oil supplied from the second branch path 147 flows to the bottom of the cavity 150.

[0058] The oil passage (main passage) 144 is bent midway and then opens at the end surface of the drive shaft 105. In other words, the oil passage 144 has an oil discharge port 148 that opens at the end surface of the drive shaft 105.

[0059] The weight portion 113 of the balance weight 111 has a through hole 114. This through hole 114 extends from a first surface facing the end face of the drive shaft 105 having the oil discharge port 148 to a second surface on the opposite side. The oil discharge port 148 is provided so as to face the opening of the through hole 114 (see also FIG. 3 ) in the first surface of the weight portion 113. The through hole 114 opens in the second surface so as to face the side of the bearing 124. This allows oil discharged from the oil discharge port 148 to be efficiently supplied to the bearing 124. The oil that lubricates the bearing 124 falls to the bottom of the cavity 150.

[0060] As the orbiting scroll 220 oscillates, the end face of the end plate 211 of the orbiting scroll 220 slides against the thrust plate 160 made of a highly wear-resistant material that is sandwiched between the opposing surfaces of the motor block 100 and the compression / discharge block 200. The oil that falls to the bottom of the cavity 150 wets the end face of the end plate 211 of the orbiting scroll 220, and also contributes to lubrication of the sliding surface between this end face and the thrust plate 160.

[0061] It is possible that some of the oil that has wetted the end face of the end plate 211 of the orbiting scroll 220 may enter between the fixed scroll 210 and the orbiting scroll 220 and contribute to lubrication therebetween. However, in this embodiment, lubrication between the fixed scroll 210 and the orbiting scroll 220 is mainly performed by the oil mist contained in the working medium supplied from the working medium supply hole 130.

[0062] The oil that has accumulated at the bottom of the cavity 150 passes through an oil passage 151 that extends downward (diagonally downward in the illustrated example) from the bottom of the cavity 150 and falls into the oil storage space 108 .

[0063] Because the working medium is adiabatically compressed in the compression chamber 206 of the scroll compression mechanism 204, the working medium is at a high temperature immediately after leaving the scroll compression mechanism 204, and therefore the oil separated from the working medium and accumulated in the oil separation chamber 260 is also at a high temperature. Therefore, the oil flowing from the oil separation chamber 260 through the oil return passage 280 into the oil storage space 108 of the motor chamber 101 is also at a relatively high temperature.

[0064] In this embodiment, the distance between the oil return hole 286 of the oil return passage 280 and the oil suction hole 142 is sufficiently large so that the relatively high-temperature oil that flows from the oil separation chamber 260 through the oil return passage 280 into the oil storage space 108 of the motor chamber 101 is not immediately sucked into the oil pump 140 through the oil suction hole 142.

[0065] Specifically, the oil return hole 286 and the oil suction hole 142 are provided near both ends of the motor chamber 101. In other words, the oil return hole 286 and the oil suction hole 142 are located on opposite sides of the motor 102 in the axial direction of the drive shaft 105.

[0066] This allows the temperature to be uniformed by the diffusion of oil within the oil storage space 108, and the oil whose temperature has been reduced by heat dissipation from the oil within the oil storage space 108 to the outside through the wall of the motor block 100 is then drawn into the oil pump 140. This prevents high-temperature, low-viscosity oil that is not suitable for lubrication from being supplied to parts that need to be lubricated, such as bearings, thereby preventing wear, damage, and other problems from occurring in the parts that need to be lubricated.

[0067] Furthermore, as described above, the working medium supply hole 130 is located at a position higher than the oil level L (see L in FIG. 2 ) in the motor chamber 101, so high-temperature oil that flows out from the oil return hole 286 into the motor chamber 101 does not immediately flow into the scroll compression mechanism 204. If high-temperature, low-viscosity oil is supplied to the scroll compression mechanism 204, there is a risk of damage to the scroll compression mechanism 204 due to poor lubrication. Furthermore, if high-temperature oil is supplied to the scroll compression mechanism 204, there is a risk of the working medium being drawn into the scroll compression mechanism 204 being heated, resulting in a decrease in compression efficiency. According to this embodiment, it is possible to prevent such problems from occurring.

[0068] In this embodiment, before the working medium discharged from the scroll compression mechanism 204 flows out of the housing 2 through the discharge port 263, the oil in the working medium is separated by the oil separation structure 261, and the separated oil is returned to the oil storage space 108 in the motor chamber 101. Therefore, the amount of oil that flows into the refrigeration cycle connected to the electric compressor 1 is extremely small, and a sufficient amount of oil is always present in the oil storage space 108. As a result, there is no shortage of oil to lubricate the components in the electric compressor 1.

[0069] REFERENCE SIGNS LIST 1 Electric compressor 2 Housing 101 Motor chamber 102 Motor 105 Drive shaft 106, 107 Drive shaft bearing 108 Oil storage space 109 Suction port 111, 124, 225 Parts attached to orbiting scroll 130 Working medium supply hole 140 Oil pump 142 Oil suction hole 144 Oil supply passage 204 Scroll compression mechanism 210 Fixed scroll 214 Discharge hole 220 Orbiting scroll 263 Discharge port 261 Oil separator (oil separation structure) 280 Oil return passage 286 Oil return hole

Claims

1. A scroll compression mechanism (204) including: a housing (2) having a suction port (109) and a discharge port (263) for a working medium; a drive shaft (105) rotatably supported in a motor chamber (101) in the housing (2); a motor (102) accommodated in the motor chamber (101) in the housing (2) and rotating the drive shaft (105); a fixed scroll (210) fixed to the housing (2); and an orbiting scroll (220) attached to one end of the drive shaft (105) and driven by the drive shaft (105); an oil pump (140) attached to the other end of the drive shaft (105), driven by the drive shaft (105), and supplying oil drawn from an oil storage space (108) provided in a lower part of the motor chamber (101) to lubrication target parts (106, 107, 111, 124, 220, 225) of the scroll compression mechanism (204) via an oil supply passage (144) provided inside the drive shaft (105); and an oil separator (261) provided in the housing (2) and separating oil from a working medium compressed by the scroll compression mechanism (204), wherein an oil return passage (280) is provided in the housing (2) for returning the oil separated by the oil separator (261) to the oil storage space (108) of the motor chamber (101).

2. The electric compressor as described in claim 1, wherein the lubrication target parts (106, 107, 111, 124, 220, 225) to which oil is supplied via the oil supply passage (144) inside the drive shaft (105) do not include the sliding surfaces between the fixed scroll (210) and the orbiting scroll (220), and the sliding surfaces are lubricated by oil contained in the working medium sucked into the scroll compression mechanism (204).

3. The electric compressor according to claim 1, wherein the oil separated in the oil separator (261) is returned to the oil storage space (108) of the motor chamber (101) through the oil return passage (280) without passing through the parts to be lubricated.

4. The electric compressor as described in claim 1, wherein the oil return passage (280) terminates at an oil return hole (286) opening into the motor chamber (101), the oil pump (140) draws oil from an oil suction hole (142) opening into the oil storage space (108) in the motor chamber (101), and the oil return hole (286) and the oil suction hole (142) are provided on opposite sides of the motor (102).

5. The electric compressor according to claim 1, wherein the housing (2) has a partition wall (118) separating the motor chamber (101) from a space in which the scroll compression mechanism (204) is disposed, the partition wall (118) is provided with one or more working medium supply holes (130) for passing the working medium that has flowed into the motor chamber (101) from the suction port (109) toward the space in which the scroll compression mechanism (204) is disposed, the oil return passage (280) terminates at an oil return hole (286) provided in the partition wall (118) that opens into the motor chamber (101), and the working medium supply hole (130) is located above the oil return hole (286).

6. An electric compressor as described in claim 5, wherein the working medium supply hole (130) is provided at a position higher than the oil level in the oil storage space (108) of the motor chamber (101) during normal operation of the electric compressor (1).

7. The electric compressor according to claim 1, wherein at least a portion (282, 283) of the oil return passage (280) penetrates a wall that constitutes the fixed scroll (210).

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