motor

Abstract

We propose a technology to suppress the temperature rise of the motor. [Solution] The motor has a case and a stator core housed inside the case. The stator core has a cylindrical shape. Also, a part of the outer surface of the stator core faces the bottom surface of the case. The case is configured to house a coolant. A coolant flow path is provided inside the stator core. The coolant flow path has an outlet on the end face of the stator core, and the outlet of the coolant flow path is positioned lower than the intended coolant level. In the motor, when coolant is discharged from the outlet of the coolant flow path, a flow is generated in the coolant stored at the bottom of the case. Therefore, the temperature rise of the stator core can be suppressed.

Description

Technical Field

[0001] The technology disclosed in this specification relates to a motor.

Background Art

[0002] Patent Document 1 describes a technique for cooling a bearing with oil.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] There is known a motor in which a coolant (for example, oil) is stored in a case. The coolant is stored at the bottom of the case. When the flow of the coolant stored at the bottom of the case stagnates during the operation of the motor, the cooling efficiency of the motor decreases. In this specification, a technique for suppressing the temperature rise of the motor is proposed.

Means for Solving the Problems

[0005] The motor disclosed in this specification has a case and a stator core housed in the case. The stator core has a cylindrical shape, and a part of the outer peripheral surface of the stator core faces the bottom surface of the case. The case is configured to store a coolant inside. A coolant flow path is provided inside the stator core, the coolant flow path has an outlet at an end surface of the stator core, and the outlet of the coolant flow path is disposed at a position lower than a planned liquid level position of the coolant.

[0006] In the motor described above, the outlet of the coolant flow path located in the stator core is positioned lower than the intended coolant level. Therefore, when coolant is discharged from the outlet of the coolant flow path, a flow is generated in the coolant stored at the bottom of the case. This helps to suppress the temperature rise of the stator core. [Brief explanation of the drawing]

[0007] [Figure 1] This is a disassembled perspective view of the motor. [Figure 2] This is a partial cross-sectional view of the motor. [Figure 3] This is a top view of the coolant flow path within the second core. [Modes for carrying out the invention]

[0008] The motor 10 shown in Figure 1 has a rotor 12, a stator 20, and a case 50. The rotor 12 has a shaft 14. The stator 20 has a cylindrical shape. The rotor 12 is positioned within the central hole of the stator 20 such that the central axis of the shaft 14 and the central axis of the stator 20 coincide. The rotor 12 and stator 20 are housed in the case 50. Hereinafter, the direction parallel to the rotation axis of the motor 10 (i.e., the central axis of the shaft 14) will be referred to as the axial direction, the direction along the radius of the circle centered on the rotation axis of the motor 10 will be referred to as the radial direction, and the direction along the circle centered on the rotation axis of the motor 10 will be referred to as the circumferential direction.

[0009] As shown in Figure 2, the case 50 has an outer peripheral wall 52. The outer peripheral wall 52 has a cylindrical shape that extends substantially horizontally. The case 50 also has partition walls 53, 54, and 55 that extend substantially vertically. Partition wall 53 is provided at one end of the outer peripheral wall 52. Partition wall 55 is provided at the other end of the outer peripheral wall 52. Partition wall 54 is provided inside the case 50. Partition wall 54 divides the inside of the case 50 into a motor room 100 and a gear room 200. The lower part of the outer peripheral wall 52 forms the bottom surface 100a of the motor room 100. A coolant supply passage 52a is provided in the outer peripheral wall 52 at the top of the motor room 100. A coolant discharge passage 52b is provided in the outer peripheral wall 52 at the bottom of the gear room 200. A through hole 53a is provided in the center of partition wall 53. A through hole 54a is provided in the center of partition wall 54. A through-hole 54b is provided in the lower part of the bulkhead 54. The motor room 100 and the gear room 200 are connected through the through-hole 54b.

[0010] Coolant is stored in the motor chamber 100. In this embodiment, the coolant is oil. The coolant functions as a coolant to cool the motor 10, and also as a lubricant to lubricate the motor 10 and the gears. The planned liquid level position H1 shown in Figure 2 is the normal liquid level position of the coolant stored in the motor chamber 100. That is, normally, the coolant is accumulated in the lower part of the motor chamber 100 up to the liquid level where the liquid level is located at the planned liquid level position H1.

[0011] As shown in Figures 1 and 2, the stator 20 is housed within the motor chamber 100. The stator 20 has a stator core 22 and a coil 30. Note that in Figure 2, the coil 30 is shown in a simplified form.

[0012] The stator core 22 has a cylindrical shape. The stator core 22 is composed of multiple electromagnetic steel sheets stacked in the axial direction. The coil 30 is wound around the stator core 22. The stator core 22 has end faces 22a, 22b, and an outer peripheral surface 22c. End face 22a is one axial end face of the stator core 22, and end face 22b is the end face opposite to end face 22a. A coil end 32a is provided on end face 22a. A coil end 32b is provided on end face 22b. The coil ends 32a and 32b are the bent portions of the coil 30 wound around the stator core 22. The coil end 32a protrudes from end face 22a, and the coil end 32b protrudes from end face 22b. End face 22a of the stator core 22 faces the partition wall 53. End face 22b of the stator core 22 faces the partition wall 54. The outer surface 22c of the stator core 22 extends along the outer wall 52.

[0013] The stator core 22 is provided with a plurality of first core coolant flow channels 60 and a plurality of second core coolant flow channels 66. Each first core coolant flow channel 60 extends axially from end face 22a to end face 22b of the stator core 22. Each first core coolant flow channel 60 has a coolant supply port 62 and a coolant discharge port 64. The coolant supply port 62 opens on end face 22a of the stator core 22. The coolant discharge port 64 opens on end face 22b of the stator core 22. As shown in Figure 1, the plurality of first core coolant flow channels 60 are provided distributed in the circumferential direction. As shown in Figure 2, the coolant discharge ports 64 of the first core coolant flow channels 60 are positioned higher than the planned liquid level position H1.

[0014] Each second core coolant flow path 66 extends axially from end face 22a to end face 22b of the stator core 22. Each second core coolant flow path 66 is located at the bottom of the stator core 22. Each second core coolant flow path 66 is positioned lower than the first core coolant flow path 60. As shown in Figure 3, when the motor 10 is viewed from above, each second core coolant flow path 66 is inclined at an angle α with respect to the axial direction. The angle α is between 20 and 45 degrees. The second core coolant flow path 66 has a coolant supply port 68 and a coolant discharge port 70. The coolant supply port 68 opens to end face 22a of the stator core 22. The coolant discharge port 70 opens to end face 22b of the stator core 22. The coolant discharge port 70 of the second core coolant flow path 66 is positioned lower than the planned liquid level position H1. In other words, the coolant outlet 70 of the coolant flow path 66 inside the second core is located inside the coolant stored in the motor chamber 100.

[0015] The rotor 12 is positioned concentrically with the stator core 22 and within the central hole of the stator core 22. The shaft 14 of the rotor 12 is inserted through through holes 53a and 54a of the case 50. The rotor 12 is rotatably supported within the case 50 by bearings or the like.

[0016] As shown in Figures 1 and 2, the motor 10 has a guide ring 40. The guide ring 40 has a ring shape. The guide ring 40 is housed in the motor chamber 100. The guide ring 40 is arranged to extend in an annular shape around the shaft of the motor 10 (i.e., the shaft 14). The guide ring 40 is positioned between the end face 22a of the stator core 22 and the partition wall 53. One end of the guide ring 40 is in contact with the end face 22a, and the other end of the guide ring 40 is in contact with the partition wall 53. Although not shown, the guide ring 40 is in contact with the end face 22a via a sealing member (e.g., a gasket). Also, although not shown, the guide ring 40 is in contact with the partition wall 53 via a sealing member (e.g., a gasket). In the radial direction, the coil end 32a is positioned inside the guide ring 40.

[0017] As shown in Figure 2, the guide ring 40 divides the space between the stator core 22 and the partition wall 53 into an outer peripheral space 56 and an inner peripheral space 57. The coil end 32a is located within space 57. The outer peripheral space 56 is a space enclosed by the inner surface of the case 50, the outer peripheral surface and end face 22a of the guide ring 40, and has a ring shape. Hereinafter, the outer peripheral space 56 will be referred to as the connecting passage 56. The connecting passage 56 is connected to the coolant supply passage 52a, the coolant supply port 62 of the first core internal coolant passage 60, and the coolant supply port 68 of the second core internal coolant passage 66. The guide ring 40 is provided with a coolant discharge passage 42. The coolant discharge passage 42 extends from the outer peripheral surface to the inner peripheral surface of the guide ring 40. The connecting passage 56 and space 57 are connected by the coolant discharge passage 42.

[0018] Within the motor chamber 100, a space 58 is provided between the end face 22b of the stator core 22 and the partition wall 54. Coolant is stored in the lower part of the space 58.

[0019] The shaft 14 of the rotor 12 extends from the motor chamber 100 to the gear chamber 200, passing through the partition wall 54. Although not shown, the gear chamber 200 is provided with multiple gears that engage with the shaft 14. For example, the multiple gears in the gear chamber 200 may constitute a reduction gear. The gear chamber 200 is connected to the space 58 of the motor chamber 100 by a through hole 54b. Therefore, coolant is stored in the lower part of the gear chamber 200.

[0020] The coolant discharge channel 52b, located at the bottom of the gear chamber 200, is connected to the coolant supply channel 52a, located at the top of the motor chamber 100, by a coolant circulation channel (not shown) located outside the case 50. A pump (not shown) is provided in the coolant circulation channel. When the motor 10 is operating, the pump supplies coolant from the coolant discharge channel 52b to the coolant supply channel 52a. The coolant flows from the coolant supply channel 52a to the connecting channel 56. The coolant in the connecting channel 56 is discharged toward the coil end 32a by the coolant discharge channel 42. This cools the coil end 32a. The coolant in the connecting channel 56 also flows to the first core internal coolant channel 60 via the coolant supply port 62. The stator core 22 is cooled by the coolant flowing through the first core internal coolant channel 60. The coolant that has passed through the first core internal coolant channel 60 flows into the space 58 from the coolant discharge port 64. Furthermore, the coolant in the connecting passage 56 flows to the second core coolant passage 66 via the coolant supply port 68. The coolant that has passed through the second core coolant passage 66 flows into the space 58 from the coolant outlet 70. In this way, coolant is supplied to the space 58 from the first core coolant passage 60 and the second core coolant passage 66, so coolant is stored in the lower part of the space 58. The coolant in the space 58 flows into the gear chamber 200 via the through hole 54b. In this way, the motor 10 is cooled when the motor 10 is in operation by the circulation of the coolant. In addition, the rotor 12 and the gears in the gear chamber 200 are lubricated by the coolant.

[0021] The coolant flowing through the coolant flow path 60 in each first core is heated by heat exchange with the stator core 22. If the high-temperature coolant passing through the coolant flow path 60 in the first core stays in the space 58, the cooling efficiency of the stator core 22 decreases. In contrast, in this embodiment, the coolant discharge port 70 of the coolant flow path 66 in the second core is arranged at a position lower than the planned liquid level position H1 (i.e., the liquid level of the coolant). Therefore, the coolant discharged from the coolant discharge port 70 flows together with the coolant in the space 58. As a result, the coolant stored in the space 58 flows toward the gear chamber 200, and the retention of the high-temperature coolant in the space 58 is suppressed. For this reason, the temperature rise of the stator core 22 can be suppressed.

[0022] Further, the coolant flow path 66 in the second core is provided inclined with respect to the axial direction. Therefore, the coolant discharged from the coolant discharge port 70 generates a turbulent flow in the coolant accommodated in the space 58. The generated turbulent flow stirs the coolant accommodated in the space 58. Thereby, the temperature rise of the stator core 22 can be more effectively suppressed.

[0023] Also, during the operation of the motor 10, wear powder is generated by the wear of metal parts in the motor chamber 100. If the coolant stays in the space 58, the wear powder accumulates on the bottom surface 100a of the motor chamber 100 in the coolant in the space 58. In contrast, in this embodiment, since the coolant discharged from the coolant discharge port 70 stirs the coolant in the space 58, the accumulation of the wear powder in the space 58 can be suppressed. As a result, the deterioration of the insulation performance of the motor 10 can be suppressed.

[0024] Although embodiments have been described in detail above, these are merely illustrative and do not limit the scope of the claims. The technologies described in the claims include various modifications and changes to the specific examples illustrated above. The technical elements described in this specification or drawings exhibit technical usefulness individually or in various combinations, and are not limited to the combinations described in the claims at the time of filing. Furthermore, the technologies illustrated in this specification or drawings achieve multiple objectives simultaneously, and achieving even one of these objectives constitutes technical usefulness. [Explanation of Symbols]

[0025] 10: Motor, 22: Stator core, 22c: Outer surface, 50: Case, 52: Outer wall, 66: Coolant flow path inside the second core, 70: Coolant outlet, 100a: Bottom surface, H1: Planned liquid level position

Claims

[Claim 1] It is a motor, The case and, The stator core housed within the aforementioned case, It has, The stator core has a cylindrical shape, A portion of the outer surface of the stator core faces the bottom surface of the case, The aforementioned case is configured to contain a coolant inside, A coolant flow path is provided inside the stator core, The coolant flow path has an outlet at the end face of the stator core, The outlet of the coolant flow path is positioned lower than the planned coolant level. Motor.

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