motor

Abstract

The cooling pipes are optimally installed inside the case while suppressing an increase in the size of the motor. [Solution] A motor comprising a case, a stator housed within the case, a cooling pipe for discharging coolant toward the stator, and bolts. The stator core of the stator has a cylindrical outer surface, a protrusion projecting from the outer surface, bolt fastening holes provided in the protrusion, and stress relief holes provided on the end face of the stator core and positioned within the angular range of the protrusion around the central axis. The stator core is fastened to the case with the bolts inserted through the bolt fastening holes. The cooling pipe has a pipe body and a hook portion connected to the pipe body. The hook portion is inserted into the stress relief holes.

Description

Technical Field

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

[0002] The motor disclosed in Patent Document 1 has a case, a stator, and cooling pipes. Inside the case, the stator and the cooling pipes are arranged. The base of the cooling pipe is fixed to the case. A pump for supplying a coolant is provided in the case. The coolant is supplied from the pump to the cooling pipes. The cooling pipes discharge the coolant toward the stator.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In Patent Document 1, the cooling pipes are fixed to the case at the base. In this structure, the cooling pipes are likely to vibrate, and the NV performance of the motor deteriorates. Also, if a structure for fixing the cooling pipes to the case is added for vibration suppression, the motor becomes larger. In this specification, a technique for suitably installing the cooling pipes in the case while suppressing the enlargement of the motor is proposed.

Means for Solving the Problems

[0005] The motor disclosed herein comprises a case having a coolant supply passage, a stator housed within the case, a cooling pipe, and bolts. The cooling pipe is housed within the case, connected to the coolant supply passage, and discharges coolant toward the stator. The stator has a stator core made of a magnetic material. The stator core has a cylindrical outer surface, protrusions projecting from the outer surface, bolt fastening holes provided in the protrusions and extending in a direction parallel to the central axis of the stator core, and stress relief holes. The stress relief holes are provided on the end face of the stator core, are located within the angular range of the protrusions around the central axis, and extend in a direction parallel to the central axis. The bolts fasten the stator core to the case with the bolts inserted through the bolt fastening holes. The cooling pipe has a pipe body and a hook portion connected to the pipe body. The hook portion is inserted into the stress relief holes.

[0006] In this motor, the protrusions of the stator core are fastened to the case by bolts. Therefore, stress is applied to the protrusions from the bolts. The stress relief holes prevent the stress applied to the protrusions from being applied to the region of the stator core that is on the inner side of the stress relief holes (i.e., closer to the central axis). This suppresses the deterioration of the magnetic properties of the stator core. In addition, the cooling pipes have hook portions, which are inserted into the stress relief holes. Since the cooling pipes are positioned relative to the stator core via the hook portions, the cooling pipes are less prone to vibration. Furthermore, since the cooling pipes can be positioned using the stress relief holes, there is no need to provide a dedicated structure on the stator core for positioning the cooling pipes relative to the stator core. Therefore, this structure can suppress the increase in size of the motor. [Brief explanation of the drawing]

[0007] [Figure 1] Disassembled perspective view of the motor. [Figure 2] A plan view of the motor as seen along the axial direction from the opening in the case. [Figure 3]Cross-sectional view along line III in Figure 3. [Figure 4] Cross-sectional view along line IV in Figure 3. [Figure 5] Cross-sectional view along line V in Figure 3. [Modes for carrying out the invention]

[0008] In the motor described above, at least a portion of the stress relief hole may be located within the protrusion.

[0009] This configuration allows for more effective suppression of the stress effects from the bolts.

[0010] As shown in Figure 1, the motor 10 of the embodiment has a rotor 20, a stator 30, and a case 50. The rotor 20 and the stator 30 are housed in the case 50 with their central axes C aligned. Hereinafter, the direction parallel to the central axis C will be referred to as the axial direction. The case 50 has an outer wall 52 and an end wall 54. The outer wall 52 extends along the axial direction and has a cylindrical shape with a substantially square cross-section. The end wall 54 extends along a plane intersecting the central axis C and is provided at one end of the outer wall 52 in the axial direction. As shown in Figure 3, a cover member 58 is fixed to the opening of the case 50. The cover member 58 closes the opening of the case 50.

[0011] Oil is stored inside the case 50. The oil is concentrated in the lower part of the case 50. The oil functions as a lubricant to lubricate the rotor 20 and as a coolant to cool the stator 30 and rotor 20. As shown in Figure 2, an oil discharge passage 53b is provided in the lower part of the case 50. As shown in Figure 3, an oil supply passage 53a is provided in the end wall 54 of the case 50. A recess 56 is provided on the inner surface of the end wall 54 in the area including the oil supply passage 53a. An oil pump (not shown) is provided outside the case 50. The oil pump sends oil from the oil discharge passage 53b to the oil supply passage 53a via an oil passage located outside the case 50. That is, when the oil pump operates, the oil inside the case 50 is discharged to the outside of the case 50 through the oil discharge passage 53b, and oil is supplied into the case 50 from the oil supply passage 53a.

[0012] As shown in Figure 1, the stator 30 has a stator core 32 and a coil 40. The stator core 32 is made up of multiple electromagnetic steel sheets stacked in the axial direction. As shown in Figure 2, the stator core 32 has a cylindrical back yoke 33. Although not shown, multiple convex teeth are provided on the inner circumferential surface of the back yoke 33, and the coil 40 is wound around these teeth. The cylindrical outer circumferential surface of the back yoke 33 forms the outer circumferential surface 32c of the stator core 32. As shown in Figure 3, the stator core 32 has end faces 32a and 32b on both sides in the axial direction. A coil end 42a is provided on end face 32a. A coil end 42b is provided on end face 32b. The coil ends 42a and 42b are the bent portions of the coil 40 wound around the stator core 32. The coil end 42a protrudes from end face 32a, and the coil end 42b protrudes from end face 32b. As shown in Figures 1 and 2, the outer circumferential surface 32c of the stator core 32 is provided with a plurality of protrusions 38 that project from the outer circumferential surface 32c. Each protrusion 38 extends from end face 32a to end face 32b. As shown in Figure 2, each protrusion 38 is provided with a bolt fastening hole 39. As shown in Figure 5, the bolt fastening hole 39 extends along the axial direction and penetrates the protrusion 38 from end face 32a to end face 32b. A bolt 49 is inserted through each bolt fastening hole 39. The stator core 32 is fastened to the case 50 by the bolts 49.

[0013] As shown in Figure 2, the stator core 32 is provided with a plurality of stress relief holes 36. As shown in Figure 4, the stress relief holes 36 extend along the axial direction and penetrate the stator core 32 from end face 32a to end face 32b. As shown in Figure 2, the stress relief holes 36 are holes provided within the angular range R where the protrusion 38 exists around the central axis C. The stress relief holes 36 are provided closer to the central axis C than the bolt fastening holes 39. In this embodiment, the stress relief holes 36 are provided in a position that includes the interface B between the back yoke 33 and the protrusion 38 (i.e., the surface extended from the cylindrical outer circumferential surface 32c). Therefore, a portion of the stress relief holes 36 is located within the protrusion 38. As described above, the protrusion 38 is fastened to the case 50 by bolts 49. As a result, high stress is applied to the protrusion 38 from the bolts 49. When the stress applied from the bolts 49 is transmitted to the back yoke 33, the permeability of the back yoke 33 decreases due to the inverse magnetostrictive effect. The stress relaxation holes 36 suppress the transmission of stress applied from the bolts 49 to the protrusions 38 to the region on the inner circumference side of the stress relaxation holes 36, thereby suppressing a decrease in the magnetic properties of the back yoke 33.

[0014] As shown in Figure 1, the rotor 20 has a shaft 24. The rotor 20 is positioned within the central hole of the stator 30 such that the central axis of the shaft 24 coincides with the central axis C of the stator 30. Although not shown, a through hole is provided in the center of the end wall 54, and the shaft 24 of the rotor 20 is inserted through this through hole. Although not shown, a through hole is provided in the center of the cover member 58, and the shaft 24 of the rotor 20 is inserted through this through hole. The rotor 20 is rotatably supported relative to the case 50 by bearings (not shown).

[0015] As shown in Figures 1 and 2, the motor 10 has a cooling pipe 60. The cooling pipe 60 is made of resin. The cooling pipe 60 is housed in a case 50. The cooling pipe 60 has a pipe body 62 and a hook portion 64. The pipe body 62 is a cylindrical member that extends along the axial direction and has ends 62a and 62b in the longitudinal direction. As shown in Figures 2 and 3, the pipe body 62 is positioned between the outer circumferential surface 32c of the stator core 32 and the outer wall 52 of the case 50. As shown in Figure 3, the end 62b of the pipe body 62 is inserted into a recess 56 provided on the inner surface of the case 50 (i.e., the inner surface of the end wall 54). The end 62b may also be press-fitted into the recess 56. The pipe body 62 is fixed to the case 50 by the fit of the end 62b into the recess 56. As shown in Figure 1, the hook portion 64 is provided near the end 62a of the pipe body 62. The hook portion 64 protrudes from the side of the pipe body 62. The hook portion 64 is bent midway, and its tip extends parallel to the pipe body 62. As shown in Figures 2 and 4, the tip of the hook portion 64 is inserted into the stress relief hole 36 from the end face 32a. Alternatively, the tip of the hook portion 64 may be press-fitted into the stress relief hole 36. The pipe body 62 is fixed to the stator 30 by the engagement of the hook portion 64 with the stress relief hole 36. In this way, the cooling pipe 60 is fixed in at least two places. Therefore, the cooling pipe 60 is less prone to vibration.

[0016] As shown in Figure 3, an oil passage 66 is provided inside the pipe body 62, extending along the axis of the pipe body 62. The oil passage 66 is connected to the oil supply passage 53a at its end 62b. Therefore, when oil is supplied to the oil supply passage 53a by the oil pump described above, oil flows from the oil supply passage 53a into the oil passage 66. Multiple oil discharge ports 68a to 68d are provided on the outer circumferential wall of the pipe body 62. The oil discharge ports 68a to 68d discharge oil from the oil passage 66 toward the stator 30. Oil discharge port 68a discharges oil toward the coil end 42a. Oil discharge ports 68b and 68c discharge oil toward the outer circumferential surface 32c of the stator core 32. Oil discharge port 68d discharges oil toward the coil end 42b. By discharging oil toward the stator 30 in this way, the stator 30 is cooled.

[0017] As described above, in this motor 10, the cooling pipe 60 is fixed at its end 62b and hook portion 64. Therefore, the cooling pipe 60 is less prone to vibration. In particular, since the hook portion 64 is located adjacent to the end 62a of the pipe body 62, the cooling pipe 60 is fixed at both ends. Therefore, vibration of the cooling pipe 60 is effectively suppressed. As a result, the NV performance of the motor 10 is improved. In addition, the cooling pipe 60 is fixed to the stator core 32 by the hook portion 64 of the cooling pipe 60 fitting into the stress relief hole 36 of the stator core 32. With this configuration, there is no need to provide a dedicated structure on the stator core 32 for fixing the cooling pipe 60, so the cooling pipe 60 can be fixed to the stator core 32 without increasing the size of the motor 10. In other embodiments, a structure for fixing the cooling pipe 60 to the case 50 or the stator core 32 may be added.

[0018] Also, in the manufacturing process of the motor 10, after fixing the stator 30 in the case 50, the cooling pipe 60 can be assembled in the case 50. At this time, by moving the cooling pipe 60 along the axial direction such that the hook portion 64 is inserted into the stress relaxation hole 36 and the end portion 62b is inserted into the recess 56, the cooling pipe 60 can be easily fixed in the case 50. Therefore, the motor 10 can be efficiently manufactured.

[0019] In the above embodiment, the cooling liquid was oil, but the cooling liquid may be other liquids.

[0020] Although the embodiments have been described in detail above, these are merely examples and do not limit the scope of the claims. The technology described in the claims includes various modifications and changes of the specific examples illustrated above. The technical elements described in this specification or the drawings exhibit technical utility alone or in various combinations, and are not limited to the combinations described in the claims at the time of filing. Also, the technology illustrated in this specification or the drawings achieves multiple purposes simultaneously, and achieving one of these purposes itself has technical utility.

Explanation of Reference Numerals

[0021] 10: Motor, 20: Rotor, 30: Stator, 32: Stator Core, 36: Stress Relaxation Hole, 38: Protrusion, 39: Bolt Fastening Hole, 40: Coil, 49: Bolt, 50: Case, 60: Cooling Pipe, 62: Pipe Body, 64: Hook Portion

Claims

1. It is a motor, A case having a coolant supply passage, The stator housed in the aforementioned case, A cooling pipe housed within the aforementioned case, connected to the coolant supply passage, and discharging coolant toward the stator, bolt, It has, The stator has a stator core made of a magnetic material, The stator core, The cylindrical outer surface, The convex portion protruding from the outer peripheral surface, The aforementioned protrusion is provided with a bolt fastening hole that extends in a direction parallel to the central axis of the stator core, A stress relaxation hole is provided on the end face of the stator core, is positioned within the angular range of the protrusion around the central axis, and extends along a direction parallel to the central axis, It has, The bolt fastens the stator core to the case with the bolt inserted through the bolt fastening hole. The cooling pipe has a pipe body and a hook portion connected to the pipe body. The hook portion is inserted into the stress relief hole. Motor.

2. The motor according to claim 1, wherein at least a portion of the stress-relieving hole is located within the protrusion.

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