Motor device and method for manufacturing motor device

Abstract

This motor device is provided with: a stator core; a fixing ring that is disposed around the stator core and that is fixed to the stator core; a motor case that is disposed around the fixing ring; and a refrigerant flow path that is provided between the fixing ring and the motor case.

Description

Motor device and method of manufacturing the same

[0001] The present disclosure relates to a motor device and a method for manufacturing the motor device.

[0002] 2. Description of the Related Art In the technical field of motor devices, a stator core cooling structure such as that disclosed in Patent Document 1 is known.

[0003] JP 2016-086611 A

[0004] There is a demand for a motor device that can be easily assembled while still having a refrigerant flow path.

[0005] An object of the present disclosure is to provide a motor device that is easy to assemble while having a refrigerant flow path.

[0006] According to the present disclosure, a motor device is provided that includes a stator core, a fixing ring arranged around the stator core and fixed to the stator core, a motor case arranged around the fixing ring, and a coolant flow path provided between the fixing ring and the motor case.

[0007] According to the present disclosure, it is possible to provide a motor device that is provided with a refrigerant flow path and that can be easily assembled.

[0008] Fig. 1 is a longitudinal sectional view showing a motor device according to an embodiment. Fig. 2 is a plan sectional view showing the motor device according to an embodiment. Fig. 3 is a longitudinal sectional view showing a part of the motor device according to an embodiment. Fig. 4 is a perspective view showing a case main body according to an embodiment. Fig. 5 is a perspective view showing a fixing ring according to an embodiment. Fig. 6 is a sectional view showing a positioning structure for a stator according to an embodiment.

[0009] Hereinafter, embodiments will be described with reference to the drawings. The components of the embodiments described below can be combined as appropriate. In addition, some components may not be used.

[0010] In the embodiment, the direction parallel to the rotation axis AX of the rotor 7 will be referred to as the axial direction, the radial direction of the rotation axis AX of the rotor 7 will be referred to as the radial direction, and the direction circumferentially around the rotation axis AX of the rotor 7 will be referred to as the circumferential direction or the rotation direction.

[0011] A position or direction on one side in the axial direction will be referred to as the upper side or the upper direction, as appropriate, and a position or direction on the other side in the axial direction will be referred to as the lower side or the lower direction, as appropriate. In the radial direction, a position or direction close to the rotation axis AX of the rotor 7 will be referred to as the radially inner side or the inner direction, as appropriate, and a position or direction far from the rotation axis AX of the rotor 7 will be referred to as the radially outer side or the outer direction, as appropriate. A position or direction on one side in the circumferential direction will be referred to as the forward side or the forward direction, as appropriate, and a position or direction on the other side in the circumferential direction will be referred to as the reverse side or the reverse direction, as appropriate.

[0012] [Motor device] Fig. 1 is a longitudinal sectional view showing a motor device 1 according to an embodiment. Fig. 2 is a plan sectional view showing the motor device 1 according to an embodiment. Fig. 2 corresponds to the cross-sectional view taken along line A-A in Fig. 1. The motor device 1 generates a rotational force for driving a hydraulic pump of, for example, an electric hydraulic excavator, which is a type of construction machine.

[0013] The motor device 1 includes a motor assembly 2 and a motor case 3. The motor assembly 2 includes a rotor 7, a stator 8, and a fixing ring 9. The motor assembly 2 is an inner rotor type. The stator 8 is disposed around the rotor 7. The rotor 7 rotates about a rotation axis AX.

[0014] The rotor 7 has a rotor core 7A, a magnet 7B, and a rotor shaft 7C.

[0015] The rotor core 7A includes a plurality of stacked steel plates. The steel plates are made of a metal whose main component is iron. The rotor core 7A is disposed to surround the rotation axis AX.

[0016] The magnet 7B is a permanent magnet. The magnet 7B is supported by the rotor core 7A. The magnet 7B is disposed inside the rotor core 7A. A plurality of magnets 7B are disposed around the rotation axis AX.

[0017] The rotor core 7A has a plurality of magnet holes spaced apart in the circumferential direction. The plurality of magnet holes are spaced apart in the circumferential direction at equal intervals. The magnet holes are formed so as to penetrate the upper end surface and the lower end surface of the rotor core 7A. The magnets 7B are disposed in the magnet holes. In this embodiment, the number of magnet holes is 24. In this embodiment, the magnets 7B are divided into a plurality of parts in the axial direction and disposed inside the rotor core 7A.

[0018] The rotor shaft 7C extends in the axial direction. The central axis of the rotor shaft 7C coincides with the rotation axis AX. The rotor shaft 7C is disposed inside the rotor core 7A. The rotor core 7A and the rotor shaft 7C are fixed. The upper part of the rotor shaft 7C protrudes upward from the upper end surface of the rotor core 7A. The lower part of the rotor shaft 7C protrudes downward from the lower end surface of the rotor core 7A.

[0019] The stator 8 includes a stator core 13 , an insulator 14 fixed to the stator core 13 , and a coil 15 attached to the stator core 13 via the insulator 14 .

[0020] The stator core 13 is arranged around the rotor core 7A. The stator core 13 includes a plurality of stacked steel plates. The steel plates are metal plates whose main component is iron. The stator core 13 has an annular yoke and a plurality of teeth that protrude radially inward from the inner peripheral surface of the yoke. The yoke is arranged to surround the rotation axis AX. A plurality of teeth are arranged circumferentially. The plurality of teeth are arranged at equal intervals circumferentially. A slot is provided between adjacent pairs of teeth.

[0021] The insulator 14 is disposed so as to cover at least a portion of the surface of the stator core 13. The insulator 14 is an electrically insulating member made of synthetic resin. The insulator 14 is fixed to the stator core 13. The stator core 13 and the coils 15 are electrically insulated by the insulator 14. In the embodiment, the insulator 14 is molded by any molding method, such as injection molding, and then attached to the stator core 13.

[0022] The coils 15 are wound around the teeth via the insulators 14. In the embodiment, the coils 15 are wound around the teeth by concentrated winding. A portion of the coils 15 is disposed inside the slots. A portion of the coils 15 protrudes upward from the upper end surface of the stator core 13. A portion of the coils 15 protrudes downward from the lower end surface of the stator core 13. In the embodiment, the coils 15 are wound one by one around each tooth. That is, one coil 15 is wound around each tooth.

[0023] The fixing ring 9 is disposed around the stator core 13. The fixing ring 9 is fixed to the stator core 13.

[0024] The motor case 3 houses the motor assembly 2. The motor case 3 houses a rotor 7, a stator 8, and a fixing ring 9. The motor case 3 is disposed around the fixing ring 9. The motor case 3 has a case body 4 and a case lid 5.

[0025] Fig. 3 is a longitudinal cross-sectional view showing a portion of the motor device 1 according to the embodiment. Fig. 3 corresponds to an enlarged view of a portion of Fig. 1. Fig. 4 is a perspective view showing the case main body 4 according to the embodiment. Fig. 5 is a perspective view showing the fixing ring 9 according to the embodiment. The case main body 4 has a cylindrical case portion 4A, a case bottom portion 4B arranged at the lower end of the cylindrical case portion 4A, and a case flange portion 4C arranged at the upper end of the cylindrical case portion 4A. The case main body 4 has a refrigerant supply circuit 21 and a refrigerant discharge circuit 22.

[0026] The case bottom portion 4B is provided with a groove 4E for inserting the seal member 12. The groove 4E is disposed on the radially inner side of the case cylindrical portion 4A.

[0027] The case flange 4C extends radially outward from the upper end of the case tubular portion 4A. A plurality of threaded holes 4D are provided in the case flange 4C. Thread grooves are formed on the inner surfaces of the threaded holes 4D. The plurality of threaded holes 4D are provided at intervals in the circumferential direction. The case flange 4C is provided with grooves 4F for inserting the seal member 11. The grooves 4F are positioned radially inward of the threaded holes 4D.

[0028] A refrigerant flow path 23 is formed on the inner circumferential surface of the cylindrical case portion 4A. The refrigerant flow path 23 is formed so as to be recessed radially outward from the inner circumferential surface of the cylindrical case portion 4A. The refrigerant flow path 23 is formed on the inner circumferential surface of the cylindrical case portion 4A so as to form a wave shape. The refrigerant flow path 23 is provided so as to go around the rotation axis AX. The refrigerant flow path 23 may be spiral.

[0029] The case lid 5 is disposed so as to close the opening at the upper end of the case body 4. The internal space of the motor case 3 is an airtight space.

[0030] The fixing ring 9 has a cylindrical portion 9A arranged around the stator core 13, a lower flange portion 9B provided at the lower end of the cylindrical portion 9A, and an upper flange portion 9C provided at the upper end of the cylindrical portion 9A.

[0031] The cylindrical portion 9A is disposed to surround the rotation axis AX. The cylindrical portion 9A contacts the outer peripheral surface of the stator core 13. The cylindrical case portion 4A is disposed around the cylindrical portion 9A. The cylindrical case portion 4A contacts the outer peripheral surface of the cylindrical portion 9A. The refrigerant flow path 23 is provided between the cylindrical portion 9A of the fixing ring 9 and the cylindrical case portion 4A of the motor case 3.

[0032] The lower flange 9B extends radially inward from the lower end of the cylindrical portion 9A. The lower flange 9B faces the case bottom 4B. The lower flange 9B is formed to cover the groove 4E of the case bottom 4B.

[0033] The upper flange portion 9C extends radially outward from the upper end of the cylindrical portion 9A. The upper flange portion 9C faces both the case flange portion 4C and the case lid 5. The upper flange portion 9C is sandwiched between the case lid 5 and the case flange portion 4C. The upper flange portion 9C is formed to cover the groove 4F of the case flange portion 4C.

[0034] The upper flange portion 9C is provided with a plurality of bolt insertion holes 9D for inserting bolts 6. The bolt insertion holes 9D are provided at intervals in the circumferential direction. The upper flange portion 9C is provided with a groove 9E for inserting a seal member 10. The groove 9E is located radially inward of the bolt insertion holes 9D. The groove 9E in the upper flange portion 9C is covered by the case lid 5.

[0035] The case lid 5 is provided with a plurality of bolt insertion holes 5D for inserting bolts 6. In a plane perpendicular to the rotation axis AX, the positions of the bolt insertion holes 5D in the case lid 5, the positions of the bolt insertion holes 9D in the upper flange portion 9C, and the positions of the screw holes 4D are aligned. The bolts 6 are inserted into the screw holes 4D through the bolt insertion holes 5D in the case lid 5 and the bolt insertion holes 9D in the upper flange portion 9C. The bolts 6 fasten the case lid 5, the fixing ring 9, and the case body 4 together.

[0036] The motor device 1 includes sealing members 10 and 11 that seal the boundary between the fixing ring 9 above the refrigerant flow path 23 and the motor case 3, and a sealing member 12 that seals the boundary between the fixing ring 9 below the refrigerant flow path 23 and the motor case 3.

[0037] The seal member 10 is inserted into the groove 9E of the upper flange portion 9C. The seal member 10 seals the boundary between the case lid 5 and the upper flange portion 9C. The seal member 10 includes an O-ring that is disposed radially inward of the bolt 6.

[0038] The seal member 11 is inserted into the groove 4F of the case flange portion 4C. The seal member 11 seals the boundary between the upper flange portion 9C and the case flange portion 4C. The seal member 11 includes an O-ring that is disposed radially inward of the bolt 6.

[0039] The seal member 12 is inserted into the groove 4E in the case bottom 4B. The seal member 12 seals the boundary between the lower flange portion 9B and the case bottom 4B. The seal member 12 includes an O-ring disposed radially inside the case cylindrical portion 4A.

[0040] The refrigerant flow path 23 is connected to each of the refrigerant supply circuit 21 and the refrigerant discharge circuit 22. The refrigerant is supplied to the refrigerant flow path 23 via the refrigerant supply circuit 21. The refrigerant flows through the refrigerant flow path 23. The refrigerant that has flowed through the refrigerant flow path 23 is discharged from the refrigerant flow path 23 via the refrigerant discharge circuit 22.

[0041] The fixing ring 9 is made of metal. In this embodiment, the fixing ring 9 is made of iron. The motor case 3 is made of metal. In this embodiment, the motor case 3 is made of aluminum. The thickness of the fixing ring 9 is thinner than the thickness of the motor case 3. The thickness of the fixing ring 9 is 2 mm or more and 10 mm or less. The thickness of the motor case 3 is 10 mm or more and 20 mm or less.

[0042] [Manufacturing Method] Next, a description will be given of a manufacturing method of the motor device 1. The stator core 13 is shrink-fitted to the fixing ring 9. With the fixing ring 9 disposed around the stator core 13, the stator core 13 and the fixing ring 9 are carried into a shrink-fitting device. Because the fixing ring 9 is thin, it reaches the shrink-fitting temperature in a short time, and the fixing ring 9 is fixed to the stator core 13.

[0043] After the stator 8 is constructed by assembling the insulators 14 and the coils 15 to the stator core 13, the fixing ring 9 is inserted into the case body 4 of the motor case 3. A refrigerant flow path 23 is formed in advance on the inner circumferential surface of the case cylindrical portion 4A of the case body 4. By inserting the fixing ring 9 into the case body 4, the refrigerant flow path 23 is formed between the cylindrical portion 9A of the fixing ring 9 and the case cylindrical portion 4A of the case body 4.

[0044] The upper flange portion 9C is provided with a plurality of bolt insertion holes 9D. The bolt insertion holes 9D can be used as openings for positioning the fixing ring 9 relative to the case body 4 of the motor case 3 in the rotational direction. When the fixing ring 9 is inserted into the case body 4, the fixing ring 9 and the motor case 3 are positioned relative to the rotational direction using the bolt insertion holes 9D.

[0045] After the fixing ring 9 has been inserted into the case body 4 with its rotational position adjusted, the rotor 7 is inserted inside the stator 8, and the case lid 5 is attached to the case body 4. The motor case 3 and the fixing ring 9 are fastened together by inserting the bolts 6 through the bolt insertion holes 5D of the case lid 5 and the bolt insertion holes 9D of the upper flange portion 9C into the threaded holes 4D. This fastens the stator 8 to the motor case 3. Alternatively, the motor case 3 and the fixing ring 9 may be fixed together by press-fitting the fixing ring 9 into the case body 4 of the motor case 3. This fixes the stator 8 to the motor case 3.

[0046] 6 is a cross-sectional view showing the positioning structure 30 for the stator 8 according to the embodiment. The positioning structure 30 suppresses relative rotation between the fixing ring 9 and the stator core 13. The positioning structure 30 positions the fixing ring 9 and the stator core 13.

[0047] The positioning structure 30 has a bolt 31 and a screw-type cap 33. A threaded hole 9F is provided in the fixing ring 9. A thread groove is formed on the inner surface of the threaded hole 9F. The bolt 31 is inserted into the threaded hole 9F. A pin 32 is provided at the tip of the bolt 31. The bolt 31 and pin 32 are integral (a single member). A recess 13A is provided on the outer surface of the stator core 13. The pin 32 is inserted into the recess 13A. The fixing ring 9 and the stator core 13 are positioned by inserting the bolt 31 into the threaded hole 9F and inserting the pin 32 provided at the tip of the bolt 31 into the recess 13A.

[0048] A threaded hole 4G is provided in the case body 4. A thread groove is formed on the inner surface of the threaded hole 4G. The cap 33 is inserted into the threaded hole 4G. When inserted into the threaded hole 4G, the cap 33 covers the bolt 31 from the radially outer side.

[0049] A seal member 34 is disposed between the bolt 31 and the fixing ring 9. The seal member 34 is an O-ring disposed so as to surround the bolt 31. The seal member 34 seals the boundary between the bolt 31 and the fixing ring 9.

[0050] A seal member 35 is disposed between the cap 33 and the case body 4. The seal member 35 is an O-ring disposed so as to surround the cap 33. The seal member 35 seals the boundary between the cap 33 and the case body 4.

[0051] [Effects] As described above, according to the embodiment, the fixing ring 9 is fixed to the outer peripheral surface of the stator core 13, and the motor case 3 is disposed around the fixing ring 9. The refrigerant flow path 23 is provided between the fixing ring 9 and the case body 4. The refrigerant flowing through the refrigerant flow path 23 comes into contact with the fixing ring 9. This makes it possible to provide a motor device 1 that is easy to assemble while including the refrigerant flow path 23.

[0052] The fixing ring 9 is lighter than the motor case 3, and the thickness of the fixing ring 9 is thinner than the thickness of the motor case 3. The method of shrink-fitting the stator core 13 to the fixing ring 9 and then fixing the fixing ring 9 to the motor case 3 by any method allows for quick and easy manufacturing of the motor device 1 compared to a method of directly shrink-fitting the stator core 13 to the motor case 3. In the method of directly shrink-fitting the stator core 13 to the motor case 3, after the stator core 13 and the motor case 3 are carried into a shrink-fitting device, it takes a long time for the motor case 3 to reach the shrink-fitting temperature. Furthermore, the motor case 3 is heavy and thick, making it difficult to handle. This may make it difficult to manufacture the motor device at low cost. In the embodiment, the fixing ring 9 is shrink-fitted to the stator core 13, and then fixed to the motor case 3 by any method, making it easy to handle. Furthermore, because the fixing ring 9 is thin, it reaches the shrink-fitting temperature in a short time. This allows for easy assembly of the motor device 1.

[0053] In the embodiment, sealing members 10 and 11 are provided to seal the boundary between the fixing ring 9 above the refrigerant flow path 23 and the motor case 3, and sealing member 12 is provided to seal the boundary between the fixing ring 9 below the refrigerant flow path 23 and the motor case 3. This prevents the refrigerant in the refrigerant flow path 23 from leaking out of the motor device 1.

[0054] Other Embodiments In the above-described embodiment, the bolt portion of the lifting hook may be inserted into the threaded hole 4D via the bolt insertion hole 5D of the case lid 5 and the bolt insertion hole 9D of the upper flange portion 9C.

[0055] In the above-described embodiment, the refrigerant flow path 23 is formed on the inner circumferential surface of the tubular case portion 4A. The refrigerant flow path 23 may be formed on the outer circumferential surface of the tubular portion 9A of the fixing ring 9. When the refrigerant flow path 23 is formed on the outer circumferential surface of the tubular portion 9A, the refrigerant flow path 23 is formed so as to be recessed radially inward from the outer circumferential surface of the tubular portion 9A.

[0056] 1...motor device, 2...motor assembly, 3...motor case, 4...case body, 4A...case cylindrical portion, 4B...case bottom, 4C...case flange portion, 4D...screw hole, 4E...groove, 4F...groove, 4G...screw hole, 5...case lid, 5D...bolt insertion hole, 6...bolt, 7...rotor, 7A...rotor core, 7B...magnet, 7C...rotor shaft, 8...stator, 9...fixing ring, 9A...cylindrical portion, 9B...lower flange portion, 9C...upper flange part, 9D...bolt insertion hole, 9E...groove, 9F...screw hole, 10...sealing member (first sealing member), 11...sealing member (first sealing member), 12...sealing member (second sealing member), 13...stator core, 13A...recess, 14...insulator, 15...coil, 21...refrigerant supply circuit, 22...refrigerant discharge circuit, 23...refrigerant flow path, 30...positioning structure, 31...bolt, 32...pin, 33...cap, 34...sealing member, 35...sealing member.

Claims

1. A motor device comprising: a stator core; a fixing ring arranged around the stator core and fixed to the stator core; a motor case arranged around the fixing ring; and a refrigerant flow path provided between the fixing ring and the motor case.

2. The motor device as described in claim 1, comprising: a first seal member that seals the boundary between the fixed ring and the motor case on one axial side of the refrigerant flow path; and a second seal member that seals the boundary between the fixed ring and the motor case on the other axial side of the refrigerant flow path.

3. A motor device as described in claim 2, wherein the fixing ring has a cylindrical portion arranged around the stator core and an upper flange portion provided at one axial end of the cylindrical portion, the motor case has a case cylindrical portion arranged around the cylindrical portion of the fixing ring, a case flange portion arranged at one axial end of the case cylindrical portion, and a case bottom portion arranged at the other axial end of the case cylindrical portion, and the first sealing member seals the boundary between the upper flange portion and the case flange portion.

4. A motor device as described in claim 3, wherein the fixing ring has a lower flange portion provided at the other axial end of the cylindrical portion, and the second seal member seals the boundary between the lower flange portion and the bottom of the case.

5. The motor device according to claim 3, wherein the coolant flow path is formed on the inner circumferential surface of the cylindrical case portion so as to describe a wave shape.

6. The motor device according to claim 3, wherein the upper flange portion is provided with a bolt insertion hole, the motor case is provided with a threaded hole, and a bolt is inserted into the threaded hole through the bolt insertion hole.

7. The motor device according to claim 3, wherein the upper flange portion is provided with an opening for positioning with the motor case.

8. A method for manufacturing a motor device, comprising: shrink-fitting a fixing ring onto a stator core; forming a refrigerant flow passage on an inner surface of a motor cylindrical portion of a motor case; and inserting the fixing ring into the motor case.

9. The method of manufacturing a motor device according to claim 7, further comprising: fixing the motor case and the fixing ring by press-fitting the fixing ring into the motor case.

10. The method of manufacturing a motor device according to claim 7, further comprising fastening the motor case and the fixing ring with a bolt.

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