Electric motor and working machine

Abstract

To provide an electric motor and a working machine that are capable of improving cooling performance.SOLUTION: An electric motor includes a housing for accommodating a rotor and a stator. The housing includes a cooling passage through which a first fluid flows, and a fluid reservoir for storing a second fluid that is different from the first fluid and cools the rotor and the stator. When viewed from an axial direction along a central axis of the rotor, the cooling passage is formed to follow the outer periphery of the fluid reservoir.SELECTED DRAWING: Figure 5

Description

[Technical field]

[0001] The present disclosure relates to electric motors and work machines. [Background technology]

[0002] Conventionally, electric revolving shovels equipped with an electric motor for revolving an upper revolving body have been known as construction machines. The electric motor includes a cylindrical housing with an internal storage space, a cooling oil circuit for cooling a rotor, a stator, and the like provided in the storage space with cooling oil, and a cooling water circuit for cooling from the periphery with cooling water. An oil pan is formed at the bottom of the housing. A water jacket (water passage) constituting the cooling water circuit is formed in the cylindrical part of the housing. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2014-68513 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, there is a risk that the electric motor may not be sufficiently cooled with the configuration of Patent Document 1. If the electric motor is not sufficiently cooled, loss may increase and the performance of the electric motor may deteriorate.

[0005] An object of an aspect of the present disclosure is to provide an electric motor and a work machine that can improve cooling performance. [Means for solving the problem]

[0006] An electric motor according to one aspect of the present disclosure includes a housing for accommodating a rotor and a stator. The housing includes a cooling passage through which a first fluid flows, and a fluid reservoir for storing a second fluid that is different from the first fluid and cools the rotor and the stator. When viewed in an axial direction along a central axis of the rotor, the cooling passage is formed to follow an outer periphery of the fluid reservoir. Effect of the Invention

[0007] According to the aspects of the present disclosure, it is possible to provide an electric motor and a work machine that can improve cooling performance. [Brief description of the drawings]

[0008] [Figure 1] 1 is a schematic diagram showing a work machine according to an embodiment. [Diagram 2] 1 is a diagram showing a drive system of a work machine according to an embodiment. [Diagram 3] 1 is a cross-sectional view of an electric motor according to an embodiment. [Figure 4] FIG. 2 is a perspective view of a lower case according to the embodiment. [Diagram 5] FIG. 4 is a plan view of a lower case according to the embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, an embodiment of the present disclosure will be described with reference to the drawings. In this embodiment, an electric motor is mounted on an electric slewing shovel (an example of a work machine) and is configured as a swing motor for swinging an upper swing body of the electric slewing shovel.

[0010] In the following description, expressions indicating relative or absolute arrangements, such as "parallel," "orthogonal," "center," and "coaxial," do not only mean such arrangements or states strictly, but also include arrangements or states in which there is a relative displacement with an angle or distance to the extent that the same function can be obtained with a tolerance. In the drawings used in the following description, the scale of each component may be appropriately changed to show each component with a recognizable size.

[0011] <Work machinery> Fig. 1 is a schematic diagram showing a work machine according to an embodiment. The work machine 100 according to this embodiment is an electric hydraulic excavator. The work machine 100 may be a manned vehicle that is operated by a driver, or an unmanned vehicle that is operated without a driver.

[0012] The work machine 100 includes a running body 120 , an upper rotating body 140 , and a work implement 160 .

[0013] The running body 120 supports the work machine 100 so that it can run. The running body 120 is equipped with a running device 121. The running device 121 is, for example, a pair of left and right caterpillar tracks. The running device 121 is driven by a traveling motor 122. The upper rotating body 140 is supported on the running body 120 so as to be rotatable about a rotation axis. The upper rotating body 140 performs a rotating operation relative to the running body 120 by the rotation motor 114. The upper rotating body 140 has a compartment 141 that houses a drive system.

[0014] The working machine 160 is supported movably on the upper rotating body 140. The working machine 160 is hydraulically driven. The working machine 160 includes a boom 161, an arm 162, and an attachment 163. The attachment 163 is an example of a working tool. In the example shown in FIG. 1, the attachment 163 is a bucket. In the example shown in FIG. 1, the side of the upper rotating body 140 on which the working machine 160 is supported is the front, and the opposite side with respect to the front is the rear. In this embodiment, the left-right direction refers to the left and right with respect to the front, and the up-down direction refers to the direction in which the rotation axis of the upper rotating body 140 extends.

[0015] <Work machine drive system> 2 is a diagram showing a drive system of a work machine according to an embodiment. The work machine 100 is equipped with a plurality of actuators for driving the work machine 100. The work machine 100 is equipped with an electricity storage device 111, a power supply device 112, a prime mover 113, a swing motor 114, a hydraulic pump 115, a control valve 116, a boom cylinder 117, an arm cylinder 118, an attachment cylinder 119, and a pair of travel motors 122. The electricity storage device 111, the power supply device 112, the prime mover 113, the swing motor 114, the hydraulic pump 115, and the control valve 116 are housed in a compartment 141.

[0016] The power storage device 111 supplies electric power, which is a power source for driving the work machine 100. The power storage device 111 is, for example, a battery or a capacitor. The power storage device 111 supplies electric power to the prime mover 113 and the swing motor 114 via a power supply device 112. The power supply device 112 controls the supplied electric power in accordance with the load. The power supply device 112 is, for example, an inverter device.

[0017] The prime mover 113 is an electric motor that is driven by electric power supplied from the power storage device 111. The prime mover 113 drives a hydraulic pump 115. Note that the prime mover 113 may be, for example, an internal combustion engine.

[0018] The swing motor 114 is an electric motor that is driven by power supplied from the power storage device 111. The swing motor 114 swings the upper swing body 140 relative to the traveling body 120.

[0019] The hydraulic pump 115 is driven by the prime mover 113, and supplies hydraulic oil to the boom cylinder 117, the arm cylinder 118, the attachment cylinder 119, and the traveling motor 122 via a control valve 116. The control valve 116 controls the flow rate of hydraulic oil supplied from the hydraulic pump 115 to the traveling motor 122, the boom cylinder 117, the arm cylinder 118, and the attachment cylinder 119. The traveling motor 122 is driven by the hydraulic oil supplied from the hydraulic pump 115, and operates the traveling device 121.

[0020] The boom cylinder 117 is a hydraulic cylinder for operating the boom 161 relative to the upper rotating body 140. The arm cylinder 118 is a hydraulic cylinder for operating the arm 162 relative to the boom 161. The attachment cylinder 119 is a hydraulic cylinder for operating the attachment 163 relative to the arm 162.

[0021] <Electric motor> FIG. 3 is a cross-sectional view of the electric motor 1 according to the embodiment. FIG. 4 is a perspective view of the lower case 4B according to the embodiment. FIG. 5 is a plan view of the lower case 4B according to the embodiment. The following figures include an explanation of the flows of the cooling oil and cooling water according to the embodiment. Hereinafter, the cooling oil may be simply referred to as "oil" and the cooling water may be simply referred to as "water."

[0022] In this embodiment, the electric motor 1 is a swivel motor 114. The electric motor 1 includes a rotor 2, a stator 3, and a housing 4 that accommodates the rotor 2 and the stator 3. The electric motor 1 is an inner rotor type motor in which the stator 3 is disposed outside the cylindrical rotor 2. The electric motor 1 is placed vertically so that the rotor shaft 20 of the rotor 2 is parallel to the swivel axis. The electric motor 1 is placed vertically so that the rotor shaft 20 is vertical.

[0023] In this embodiment, the upper side corresponds to one side parallel to the central axis CL of the rotor shaft 20, and the lower side corresponds to the other side parallel to the central axis CL of the rotor shaft 20. Hereinafter, the direction along the central axis CL of the rotor shaft 20 is referred to as the "axial direction", the direction perpendicular to the axial direction is referred to as the "radial direction", and the direction going around the central axis CL of the rotor shaft 20 is referred to as the "circumferential direction".

[0024] The rotor 2 includes a rotor shaft 20, a rotor core 21, an upper plate 22, and a lower plate 23. The rotor shaft 20 is rotatably supported relative to the housing 4 by bearings 21A and 21B.

[0025] The rotor core 21 is formed, for example, by laminating electromagnetic steel sheets in the axial direction. The rotor core 21 is fitted onto the rotor shaft 20. The rotor core 21 rotates integrally with the rotor shaft 20. A plurality of permanent magnets (not shown) are embedded in the rotor core 21.

[0026] Each of the upper plate 22 and the lower plate 23 is annular plate members arranged coaxially with the rotor shaft 20. The upper plate 22 and the lower plate 23 are fitted to the rotor shaft 20. The upper plate 22 and the lower plate 23 hold the rotor core 21 from the outside in the axial direction. The upper plate 22 and the lower plate 23 rotate integrally with the rotor shaft 20 and the rotor core 21.

[0027] The stator 3 is fixed to the inner surface of the housing 4 so as to cover the outer periphery of the rotor 2. The stator 3 includes a cylindrical stator core 30 and a stator coil 31. Like the rotor core 21, the stator core 30 is formed by laminating electromagnetic steel sheets in the axial direction. A plurality of teeth (not shown) are provided circumferentially on the inner periphery of the stator core 30. The stator coil 31 is wound around the teeth.

[0028] The housing 4 accommodates the rotor 2 and the stator 3. The housing 4 includes an upper case 4A and a lower case 4B that constitutes the bottom 13 of the housing 4. The housing 4 is composed of the upper case 4A and the lower case 4B. The lower case 4B is configured to close the lower opening of the upper case 4A. A space 40 for accommodating the rotor 2 and the stator 3 is formed inside the housing 4 by the upper case 4A and the lower case 4B.

[0029] The upper case 4A includes a cylindrical body 10 and a ceiling portion 11 that closes an upper opening of the cylindrical body 10 (the opening on the opposite side to the lower case 4B in the axial direction). The cylindrical body 10 and the ceiling portion 11 are integrally formed from the same member. That is, the upper case 4A is formed from a single member.

[0030] The cylinder 10 of the upper case 4A is provided with a flange 17 that protrudes radially outward from the lower end of the cylinder 10. A second fluid supply path 12 that allows cooling fluid to flow into the space 40 is provided on the ceiling portion 11 of the upper case 4A.

[0031] The lower case 4B is formed with a fluid reservoir 15 for temporarily storing the cooling fluid flowing through the space 40 via the second fluid supply passage 12. The lower case 4B is provided with a second fluid discharge passage 16 that communicates with the fluid reservoir 15 and discharges the cooling fluid from the space 40. When viewed from the axial direction along the central axis CL, the lower case 4B is formed with a cooling passage 62 along the outer periphery of the fluid reservoir 15. The lower case 4B is provided with a first fluid supply port 60 and a first fluid discharge port 61 that communicate with the cooling passage 62. The first fluid supply port 60 is a supply port of the cooling fluid that communicates with one end of the cooling passage 62. The first fluid discharge port 61 is a discharge port of the cooling fluid that communicates with the other end of the cooling passage 62. The first fluid supply port 60 and the first fluid discharge port 61 are disposed at positions adjacent to each other in the circumferential direction of the lower case 4B.

[0032] The electric motor 1 includes a first cooling circuit 6 through which a first fluid flows, and a second cooling circuit 5 through which a second fluid different from the first fluid flows. The first cooling circuit 6 is composed of a first fluid supply port 60, a cooling passage 62, and a first fluid discharge port 61. The second cooling circuit 5 is composed of a second fluid supply path 12, a fluid reservoir 15, and a second fluid discharge path 16.

[0033] In this embodiment, cooling water flows as the first fluid in the first cooling circuit 6. The first cooling circuit 6 is a circuit (hereinafter also referred to as the "cooling water circuit") that uses cooling water to cool the second fluid in the fluid reservoir 15 from the outer periphery. Meanwhile, cooling oil flows as the second fluid in the second cooling circuit 5. The second cooling circuit 5 is a circuit (hereinafter also referred to as the "cooling oil circuit") for directly cooling components such as the rotor 2 housed in the space 40 with cooling oil.

[0034] The fluid reservoir 15 is a portion where cooling oil is stored (hereinafter also referred to as an "oil pan"). The cooling passage 62 is a passage through which cooling water flows (hereinafter also referred to as a "water jacket").

[0035] <Lower case> 4 and 5, the lower case 4B includes an outer cylindrical portion 80A that is cylindrical along the axial direction, and an inner cylindrical portion 80B that is cylindrical along the axial direction and disposed radially inside the outer cylindrical portion 80A. The lower case 4B is provided with a bearing support portion that supports the bearing 21B.

[0036] When viewed from the axial direction, the oil pan 15 is formed inside the inner cylindrical portion 80B. The water jacket 62 is formed between the inner cylindrical portion 80B and the outer cylindrical portion 80A. When viewed from the axial direction, the water jacket 62 is formed in a C-shape on the radially outer side of the oil pan 15 in the lower case 4B. The water jacket 62 is formed on the lower case 4B so as to follow the outer periphery of the oil pan 15. The oil pan 15 and the water jacket 62 are formed on the lower case 4B via the inner cylindrical portion 80B.

[0037] The lower case 4B has a plurality of support pillars 81. The plurality of support pillars 81 are portions to which the stator 3 (specifically, the stator core 30) is attached. The plurality of support pillars 81 protrude axially upward from the bottom of the lower case 4B. Note that the form (shape, number, arrangement, etc.) of the support pillars 81 is not limited to the above and can be changed according to design specifications.

[0038] The stator core 30 is fixed to the support 81 by fastening members such as bolts. An internal thread is formed on the upper part of the support 81 into which the bolt is screwed. An insertion hole (not shown) is formed in the stator core 30 through which the bolt is inserted. For example, with the stator core 30 placed on the support 81 when viewed from the axial direction, a bolt is inserted into the insertion hole of the stator core 30 and screwed into the internal thread of the support 81. This allows the stator 3 to be fixed to the support 81.

[0039] The lower case 4B has a boss 82. The boss 82 is a portion for fixing the upper case 4A (specifically, the flange 17 of the cylindrical body 10). Note that the aspect (shape, number, arrangement, etc.) of the boss 82 is not limited to the above and can be changed according to the design specifications.

[0040] The flange 17 of the cylindrical body 10 is fixed to the boss 82 by a fastening member such as a bolt. The boss 82 has a female thread into which the bolt is screwed. The flange 17 of the cylindrical body 10 has an insertion hole (not shown) through which the bolt is inserted. For example, with the flange 17 of the cylindrical body 10 overlapping the boss 82 when viewed in the axial direction, the bolt is inserted into the insertion hole of the flange 17 and screwed into the female thread of the boss 82. This allows the upper case 4A to be fixed to the lower case 4B.

[0041] <Water jacket (cooling passage)> 5, a line segment connecting one end of the water jacket 62 and the central axis CL as viewed from the axial direction is defined as a first line segment L1. A line segment connecting the other end of the water jacket 62 and the central axis CL as viewed from the axial direction is defined as a second line segment L2. An angle CA formed between the first line segment L1 and the second line segment L2 as viewed from the axial direction (specifically, the larger of the two angles formed by the first line segment L1 and the second line segment L2 as viewed from the axial direction) is defined as a central angle CA. As viewed from the axial direction, the water jacket 62 is formed so that the central angle CA extends continuously within a range of more than 225° and less than 360°.

[0042] For example, the central angle CA is preferably equal to or greater than 300°, more preferably equal to or greater than 350°, and even more preferably approximately 360°. Note that the range of the central angle CA is not limited to the above and can be changed according to the design specifications.

[0043] In this embodiment, the water jacket 62 is formed in a C-shape radially outward of the oil pan 15 as viewed in the axial direction. The water jacket 62 is formed in a C-shape along the circumferential direction of the outer cylindrical portion 80A as viewed in the axial direction. The water jacket 62 is formed along the inner circumference of the annular seal member 89 as viewed in the axial direction. The water jacket 62 is continuous in the circumferential direction except for a portion (partition wall portion 65) that separates the first fluid supply port 60 and the first fluid discharge port 61. The partition wall portion 65 is a portion that is sandwiched between one end of the water jacket 62 and the other end of the water jacket 62 in the circumferential direction of the outer cylindrical portion 80A. The inner cylindrical portion 80B is sandwiched between the oil pan 15 and the water jacket 62 as viewed in the axial direction.

[0044] For example, the inner cylindrical portion 80B may have a protrusion 86 on its outer periphery, on a surface facing the water jacket 62. The portion of the water jacket 62 on which the protrusion 86 is provided has a smaller flow passage cross-sectional area than the other portion (the portion on which the protrusion 86 is not provided). The flow passage cross-sectional area corresponds to the cross-sectional area when the flow passage (the water jacket 62 in this embodiment) is cut by a plane perpendicular to the fluid flow direction (the direction in which the cooling water flows in this embodiment). In other words, the portion of the water jacket 62 on which the protrusion 86 is provided has a narrower flow passage width than the other portion. As a result, in the portion of the water jacket 62 on which the protrusion 86 is provided, the flow speed of the cooling water is increased, thereby improving the cooling performance.

[0045] <Cooling oil flow> 3, for example, cooling oil discharged from the cooling fluid pump 8 is sent to the inside of the electric motor 1. Specifically, the cooling oil discharged from the cooling fluid pump 8 flows into the space 40 of the housing 4 via the second fluid supply passage 12. The cooling oil flowing in from the second fluid supply passage 12 is divided into a passage 53 formed in the rotor shaft 20 and the outer ring portion of the bearing 21A. The cooling oil flowing to the outer ring portion of the bearing 21A lubricates and cools the bearing 21A.

[0046] On the other hand, when the cooling oil flows into the passage 53 formed in the rotor shaft 20 and reaches the lower end of the passage 53, it passes through a groove 54 formed in the lower plate 23 and a through passage 55 (specifically, a hole extending in the axial direction formed on each of the inner and outer circumferential sides of the rotor core 21) formed in the rotor core 21, and cools the rotor 2. The cooling oil that passes through the through passage 55 is sprayed from a cooling oil spray hole 56 into the cylinder 10. The cooling oil sprayed into the cylinder 10 drops toward the lower case 4B while cooling the stator coil 31, and lubricates and cools the bearing 21B.

[0047] The cooling oil that drops toward the lower case 4B is accumulated in an oil pan 15 formed in the lower case 4B. The cooling oil accumulated in the oil pan 15 is discharged from a second fluid discharge passage 16. The cooling oil discharged from the second fluid discharge passage 16 is sent again to the inside of the electric motor 1 by the cooling fluid pump 8.

[0048] <Cooling water flow> 5, for example, the cooling water supplied from the first fluid supply port 60 flows in the circumferential direction inside the lower case 4B through the water jacket 62 toward the first fluid discharge port 61. Specifically, the cooling water supplied from the first fluid supply port 60 flows continuously in a C-shape through the water jacket 62, and then flows out from the first fluid discharge port 61. This cools the cooling oil accumulated in the oil pan 15 formed inside the lower case 4B.

[0049] <Action and effect> As described above, the electric motor 1 of this embodiment includes a housing 4 for accommodating the rotor 2 and the stator 3. The housing 4 includes a cooling passage 62 through which a first fluid flows, and a fluid reservoir 15 for storing a second fluid that is different from the first fluid and cools the rotor 2 and the stator 3. When viewed from the axial direction along the central axis CL of the rotor 2, the cooling passage 62 is formed along the outer periphery of the fluid reservoir 15. With this configuration, the second fluid stored in the fluid reservoir 15 can be intensively cooled by the first fluid flowing through the cooling passage 62. In addition, a sufficient heat transfer area between the cooling passage 62 and the fluid reservoir 15 can be ensured. Therefore, the cooling performance can be improved.

[0050] In this embodiment, the housing 4 includes a cylindrical upper case 4A that surrounds the rotor 2 and the stator 3, and a lower case 4B that forms the bottom 13 of the housing 4 and closes an opening portion on one axial end side of the upper case 4A. The cooling passages 62 and the fluid reservoir 15 are formed in the lower case 4B. With this configuration, the cooling passages 62 and the fluid reservoir 15 can be integrated in the lower case 4B. Therefore, there is no need to form the cooling passages 62 and the fluid reservoir 15 in a separate member (a member other than the lower case 4B). This simplifies the configuration of the housing 4 and makes it easy to manufacture.

[0051] In this embodiment, a supply port 60 communicating with one end of a cooling passage 62 and a discharge port 61 communicating with the other end of the cooling passage 62 are formed in the lower case 4B. The supply port 60 and the discharge port 61 are disposed adjacent to each other in the circumferential direction of the lower case 4B. With this configuration, the supply port 60 and the discharge port 61 are close to each other in the circumferential direction of the lower case 4B, so that the cooling passage 62 can be disposed around the entire circumference of the fluid reservoir 15. This can further improve the cooling performance.

[0052] In this embodiment, the angle between a first line segment L1 connecting one end of the cooling passage 62 to the central axis CL and a second line segment L2 connecting the other end of the cooling passage 62 to the central axis CL is defined as the central angle CA when viewed from the axial direction. When viewed from the axial direction, the cooling passage 62 is formed so as to extend continuously with a central angle CA in the range of more than 225° and less than 360°. For example, when the cooling passage is formed in a plurality of branches along the outer periphery of the fluid reservoir, the fluid reservoir is locally cooled at each of the plurality of branches. In this case, it is highly likely that the heat transfer area of ​​the fluid reservoir cannot be sufficiently secured. In addition, when the sum of the central angles of the plurality of branches in the cooling passage is 225° or less, it is highly likely that the heat transfer area of ​​the fluid reservoir cannot be sufficiently secured. In contrast, according to this embodiment, when viewed from the axial direction, the cooling passage 62 is formed so as to extend continuously with a central angle CA in the range of more than 225° and less than 360°, so that the fluid reservoir 15 can be cooled in a concentrated manner. In addition, it is possible to ensure a sufficient heat transfer area of ​​the fluid reservoir 15. Therefore, it is possible to improve the cooling performance.

[0053] In this embodiment, the upper case 4A includes a cylindrical body 10 and a ceiling portion 11 that closes an opening portion of the cylinder body 10 on the opposite side to the lower case 4B in the axial direction. The cylinder body 10 and the ceiling portion 11 are integrally formed from the same member. With this configuration, the upper case 4A can be formed from a single member (one part). Therefore, the number of parts can be reduced compared to when the cylinder body 10 and the ceiling portion 11 of the upper case 4A are formed from different members.

[0054] In this embodiment, the electric motor 1 is disposed vertically so that the rotor shaft 20 of the rotor 2 is vertical. With this configuration, the cooling oil in the oil pan 15 is agitated, thereby improving the cooling performance of the oil pan 15.

[0055] <Modification> In the above embodiment, an example has been described in which the first cooling circuit is formed with a passage through which cooling water flows as a first fluid, the second cooling circuit is formed with a passage through which cooling oil flows as a second fluid, the fluid reservoir is a portion in which cooling oil accumulates, and the cooling passage is a passage through which cooling water flows, but this is not limiting. For example, the fluid reservoir may include a portion in which a fluid other than cooling oil accumulates. For example, the cooling passage may include a passage through which a fluid other than cooling water flows. The aspects of the fluid reservoir and the cooling passage can be changed according to design specifications.

[0056] In the above embodiment, the housing includes an upper case and a lower case that forms the bottom of the housing and closes the lower opening of the upper case, but the present invention is not limited to this. For example, a part of the upper case may form the bottom of the housing. For example, a fluid reservoir and a cooling passage may be formed in a part of the upper case (a member other than the lower case). The configuration of the housing may be changed according to design specifications.

[0057] In the above embodiment, the lower case is provided with a first fluid supply port leading to one end of the cooling passage and a first fluid discharge port leading to the other end of the cooling passage, and the first fluid supply port and the first fluid discharge port are disposed adjacent to each other in the circumferential direction of the lower case. However, the present invention is not limited to this. For example, the first fluid supply port and the first fluid discharge port may be disposed far apart from each other in the circumferential direction of the lower case. The arrangement of the first fluid supply port and the first fluid discharge port may be changed according to design specifications.

[0058] In the above embodiment, the upper case includes a cylindrical body and a ceiling portion, and the cylindrical body and the ceiling portion are integrally formed from the same material. However, this is not limiting. For example, the cylindrical body and the ceiling portion may be integrated from different materials (two parts). The form of the cylindrical body and the ceiling portion may be changed according to the design specifications.

[0059] In the above-described embodiment, the electric motor is mounted on an electric swing shovel, and an electric swing motor for swinging an upper swing body of the electric swing shovel has been described as an example, but the present invention is not limited thereto. For example, the electric motor may be mounted on other work machines such as a wheel loader, a bulldozer, or a dump truck. For example, the electric motor may be configured as a drive motor for driving a work machine or a drive motor for driving a traveling device. The aspect of the work machine on which the electric motor is mounted and the target driven by the electric motor can be changed according to the design specifications.

[0060] In the above-described embodiment, the electric motor is vertically disposed so that the rotor shaft is parallel to the rotation axis, but the present invention is not limited to this. For example, the electric motor may be horizontally disposed so that the rotor shaft is perpendicular to the rotation axis. For example, the electric motor may be disposed at an angle so that the rotor shaft crosses the rotation axis at an angle. The arrangement of the electric motor may be changed according to the design specifications.

[0061] In the above embodiment, the electric motor is an inner rotor type electric motor in which a stator is disposed outside a cylindrical rotor, but the present invention is not limited to this. For example, the electric motor may be an outer rotor type electric motor in which a stator is disposed inside a cup-shaped rotor. The type of the electric motor may be changed according to the design specifications.

[0062] Although one embodiment has been described above with reference to the drawings, the specific configuration is not limited to the above, and addition, omission, substitution, and other modifications of the configuration are possible without departing from the spirit of this disclosure, and the above-mentioned embodiments can also be combined as appropriate. [Explanation of symbols]

[0063] 1...electric motor, 2...rotor, 3...stator, 4...housing, 4A...upper case, 4B...lower case, 5...cooling oil circuit (second cooling circuit), 6...cooling water circuit (first cooling circuit), 10...cylinder, 11...ceiling, 13...bottom, 15...oil pan (fluid reservoir), 20...rotor shaft, 40...space, 60...first fluid supply port (supply port), 61...first fluid discharge port (discharge port), 62...water jacket (cooling passage), CA...central angle, CL...central axis, L1...first line segment, L2...second line segment

Claims

1. A housing for accommodating a rotor and a stator, The housing includes: a cooling passage through which a first fluid flows; a fluid reservoir for storing a second fluid that is different from the first fluid and that cools the rotor and the stator; When viewed in an axial direction along a central axis of the rotor, the cooling passage is formed along an outer periphery of the fluid reservoir. Electric motor.

2. The housing includes: a cylindrical upper case surrounding the rotor and the stator; a lower case that closes an opening portion of the upper case at one end in the axial direction, The cooling passage and the fluid reservoir are formed in the lower case.

2. The electric motor according to claim 1.

3. The lower case is formed with a supply port communicating with one end of the cooling passage and a discharge port communicating with the other end of the cooling passage, the supply port and the exhaust port are disposed adjacent to each other in a circumferential direction of the lower case.

3. The electric motor according to claim 2.

4. When viewed from the axial direction, an angle formed by a first line segment connecting one end of the cooling passage to the central axis and a second line segment connecting the other end of the cooling passage to the central axis is defined as a central angle, When viewed from the axial direction, the cooling passage is formed to extend continuously within a range of the central angle exceeding 225° and less than 360°.

2. An electric motor as claimed in claim 1.

5. The upper case includes: A cylindrical body; a ceiling portion that closes an opening portion of the cylindrical body on a side opposite to the lower case in the axial direction, The cylindrical body and the ceiling portion are integrally formed from the same material.

3. The electric motor according to claim 2.

6. The rotor is vertically oriented so that the rotor shaft is vertical.

2. The electric motor according to claim 1.

7. A running body, An upper rotating body supported on the traveling body so as to be rotatable about a rotating shaft; A work machine operably supported on the upper rotating body; an electric motor configured as a rotation motor for rotating the upper rotating body relative to the traveling body, The electric motor includes a housing for accommodating a rotor and a stator. The housing includes: a cooling passage through which a first fluid flows; a fluid reservoir for storing a second fluid that is different from the first fluid and that cools the rotor and the stator; When viewed in an axial direction along a central axis of the rotor, the cooling passage is formed along an outer periphery of the fluid reservoir. Working machinery.

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