Stator of the electric motor

Abstract

The present invention provides a stator of an electric motor. The heat of the stator is efficiently removed without reducing the performance of the electric motor. The stator of the electric motor comprises: a cylindrical stator core; a coil wound on the stator core; and a first cooling pipe wound on a coil end formed at an axial end of the stator core.

Description

Technical Field

[0001] The present invention relates to an electric motor, and in particular to a stator of an electric motor having a cooling pipe. Background Art

[0002] The temperature rise caused by the heating of the coil or the iron loss of the stator core is directly related to the performance degradation of the motor. Therefore, how to dissipate the heat of the stator such as the coil or the stator core is an important issue. As a method of removing the heat of the stator, there are known structures in which a cooling jacket is provided on the outer periphery of the stator core, a cooling path is provided on the stator core, and a cooling path is provided at the end of the coil. As the prior art, the following documents are known.

[0003] Japanese Patent Application Laid-Open No. 09-140097 discloses a plurality of cooling pipes which are provided so as to penetrate in the axial direction in the outer peripheral region of the stator coil inside the stator core and are arranged in the circumferential direction.

[0004] Japanese Patent Application Laid-Open No. 10-336965 discloses a cooling jacket which is inserted into a stator core and in which a plurality of spiral cooling water channels are provided inside a cylinder of the cooling jacket.

[0005] Japanese Patent Application Laid-Open No. 2003-009436 discloses a refrigerant passage formed inside a slot by accommodating a coil in a slot of a stator core and closing a slot opening that opens to the inner peripheral surface of the stator.

[0006] Japanese Patent Application Laid-Open No. 2004-048939 discloses a liquid cooling pipe having a substantially square cross section and provided in close contact with a head-side coil end and an end-side coil end.

[0007] Japanese Patent Application Laid-Open No. 2006-325369 discloses a cooling hose made of a non-magnetic heat-resistant material which is annularly disposed at an axial end of a stator so as to surround a rotor shaft and passes through the center of a cross section of a coil end.

[0008] Japanese Patent Application Laid-Open No. 2009-033898 discloses a cooling pipe located in the axial center portion of a stator.

[0009] Japanese Patent Application Laid-Open No. 2013-158237 discloses a cooling tube extending so as to penetrate a stack.

[0010] Japanese Patent Application Laid-Open No. 2017-085765 discloses that through holes are provided in a hollow fixing member fixed at equal intervals in the circumferential direction on the outer peripheral surface of a stator core, and the through holes function as cooling paths through which a cooling medium flows.

[0011] In Japanese Patent Gazette No. 2017-052387, a refrigerant supply device is disclosed, which includes: a first cooling pipe, which discharges the cooling medium from a mechanical pump from a first discharge port to the coil end side; and a second cooling pipe, which discharges the cooling medium from an electric pump from a second discharge port to the coil end side. Summary of the invention

[0012] Problem that the invention aims to solve

[0013] In the structure where the cooling jacket is provided on the outer periphery of the stator core, the stator core needs to have a predetermined thickness in the radial direction, so there is a distance between the cooling jacket and the coil, which makes the cooling efficiency low. In addition, in the cooling jacket, the coil end formed at the axial end of the stator core is difficult to cool. On the other hand, in the structure where the cooling path is provided in the slot of the stator core, the slot fill rate of the coil in the slot is reduced, so the performance of the motor may be reduced.

[0014] Therefore, a technology for efficiently removing heat generated by the stator without degrading the performance of the motor is sought.

[0015] Solutions for solving problems

[0016] One technical aspect of the present disclosure provides a stator of an electric motor, the stator of the electric motor including: a cylindrical stator core; a coil wound around the stator core; and a first cooling pipe wound around a coil end formed at an axial end of the stator core.

[0017] In the stator of the electric motor, the first cooling pipe may be spirally wound around the bundle of the coil located at the coil end, or may be wound in a circumferential direction along the bundle of the coil located at the coil end.

[0018] In the above-mentioned stator of the electric motor, the first cooling pipe may tightly bind the bundle of the coil located at the coil end portion to fix the shape of the coil.

[0019] In the above-mentioned stator of the electric motor, the first cooling pipe may be formed of a soft material.

[0020] The stator of the electric motor may further include: a through hole penetrating the stator core in the axial direction; and a second cooling pipe penetrating the through hole.

[0021] The stator of the electric motor may further include a plurality of slots formed at predetermined intervals on an inner periphery of the stator core, and the through hole may be formed between adjacent slots and near an outer periphery of the stator core.

[0022] In the above-mentioned stator of the electric motor, the first cooling pipe and the second cooling pipe may be formed of separate pipes, respectively, or the first cooling pipe and the second cooling pipe may be formed of a continuous pipe.

[0023] In the stator of the electric motor, one of the separate pipes may enter the coil end and exit from the coil end, and the other of the separate pipes may enter the stator core and exit from the stator core.

[0024] In the stator of the electric motor, the continuous tube may reciprocate between the coil end and the stator core, and an inlet and an outlet of the continuous tube may converge at an input side or an output side of the electric motor.

[0025] In the stator of the electric motor, an inlet of the single tube or the continuous tube may be arranged on an output side of the electric motor.

[0026] In the stator of the electric motor, a plurality of inlets and outlets of the first cooling pipe or the second cooling pipe may be arranged at predetermined intervals in a circumferential direction of the stator core.

[0027] The stator of the electric motor may further include a cooling jacket disposed on an outer peripheral portion of the stator core, and the refrigerant supplied to the cooling jacket may be shared with the refrigerant supplied to at least one of the first cooling pipe and the second cooling pipe.

[0028] The above-mentioned stator of the electric motor may further include a thermally conductive resin filled in a gap formed by the stator core, the coil, and the cooling jacket.

[0029] In the above-mentioned stator of the electric motor, the thermally conductive resin may be a molding resin or an impregnating resin.

[0030] Effects of the Invention

[0031] According to the present invention, the heat generated by the stator can be efficiently removed without reducing the performance of the motor. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 This is a cross-sectional view of a stator of a motor according to an embodiment.

[0033] Figure 2 This is a perspective view of a stator in which a first cooling pipe and a second cooling pipe are arranged as separate pipes.

[0034] Figure 3 This is an enlarged view of the coil end portion formed by spirally winding the first cooling tube.

[0035] Figure 4 It is a plan view of the stator core showing the arrangement of through holes through which the second cooling pipes pass.

[0036] Figure 5 This is a perspective view of a stator in which a first cooling pipe and a second cooling pipe are arranged as a continuous pipe.

[0037] Figure 6 This is a perspective view of a stator in which a plurality of inlets and outlets of cooling pipes are arranged at predetermined intervals in the circumferential direction.

[0038] Figure 7 This is a perspective view of a stator in which a first cooling pipe is wound in a circumferential direction along a coil end. DETAILED DESCRIPTION

[0039] Hereinafter, the embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. In each of the drawings, the same or similar components are marked with the same or similar reference numerals. In addition, the embodiments described below are not intended to limit the technical scope of the invention described in the claims and the meaning of the terms. It should be noted that in this specification, the term "input side" refers to the power line side of the motor, and the term "output side" refers to the output shaft side of the motor.

[0040] Figure 1 The stator 1 of the electric motor of the present embodiment is shown. The stator 1 of the present example is, for example, a stator for a spindle motor, but it can also be applied to other electric motors if the motor has a coil wound around the stator. The stator 1 includes a cylindrical stator core 10, a coil 11 wound around the stator core 10, and a first cooling tube 12 wound around the coil end formed at the end in the axial direction X of the stator core 10. Furthermore, the stator 1 may also include a through hole 13 penetrating the stator core 10 in the axial direction X and a second cooling tube 14 penetrating the through hole 13. A refrigerant is supplied to the first cooling tube 12 and the second cooling tube 14 from a cooling device 15. The heat generated by the coil end is removed by the refrigerant flowing in the first cooling tube 12, and the heat generated by the stator core 10 is removed by the refrigerant flowing in the second cooling tube 14. The first cooling tube 12 and the second cooling tube 14 may be formed by separate tubes, respectively, or may be formed by a continuous tube.

[0041] Furthermore, the stator 1 may also include a cooling jacket 16 disposed on the circumferential outer portion of the stator core 10. The cooling jacket 16 is formed of a magnetic material or the like in a manner having a spiral cooling groove 16a on the outer circumferential surface, and is fixed to the stator core 10 by, for example, shrink fit or the like. The refrigerant supplied to the cooling jacket 16 may be shared with the refrigerant supplied to the first cooling pipe 12 and the second cooling pipe 14. Due to the sharing of the refrigerant, the stator 1 can use a branch joint 17. It is preferred that the branch joint 17 includes a supply side branch joint 17a and a discharge side branch joint 17b.

[0042] The stator 1 preferably includes a stator core 10, a coil 11, and a thermally conductive resin 18 filled in a gap formed by a cooling jacket 16. For example, the gaps include a gap between the stator core 10 and the cooling jacket 16, a gap between the through hole 13 of the stator core 10 and the second cooling pipe 14, and a slot of the stator core 10 (see Figure 4 ) and the gap between the coil 11. The thermally conductive resin 18 may be a molded resin, or may be an impregnated resin impregnated in the gap. In addition, in order to improve thermal conductivity, the thermally conductive resin 18 preferably has interconnected thermally conductive fillers in the matrix resin. As thermally conductive fillers, for example, aluminum nitride, magnesium oxide, boron nitride, aluminum oxide, anhydrous magnesium carbonate, silicon oxide, zinc oxide, etc. may also be used.

[0043] Figure 2 The stator 1 is shown in which the first cooling pipe 12 and the second cooling pipe 14 are arranged as separate pipes. The stator 1 includes two first cooling pipes 12 and one second cooling pipe 14. The first cooling pipe 12 of the coil end 11a on the input side has an inlet IN1 and an outlet OUT1, and the first cooling pipe 12 of the coil end 11b on the output side has an inlet IN3 and an outlet OUT3. In addition, the second cooling pipe 14 penetrating the through hole 13 of the stator core 10 has an inlet IN2 and an outlet OUT2. One of the separate pipes (the first cooling pipe 12) enters the coil ends 11a and 11b and exits from the coil ends 11a and 11b, and the other of the separate pipes (the second cooling pipe 14) enters the stator core 10 and exits from the stator core 10. By making the first cooling pipe 12 and the second cooling pipe 14 consist of separate pipes, the cooling pipe arrangement operation during manufacturing can be easily performed.

[0044] Figure 3 This is an enlarged view of the coil end 11a formed by spirally winding the first cooling tube 12. By spirally winding the first cooling tube 12 around the bundle of the coil 11 located at the coil end 11a, the first cooling tube 12 has both the function of cooling the heated coil end 11a and the function of fixing the shape of the coil 11 by tightly binding the bundle of the coil 11 located at the coil end 11a. In order to achieve the cooling function and the tightening function without impairing the performance of the motor, the first cooling tube 12 is preferably formed of a material having properties such as electrical insulation, heat resistance, and softness. As a soft material, for example, a soft resin such as a fluororesin or a polyurethane resin is preferably used.

[0045] Figure 4Indicates the configuration of the through hole 13 for the second cooling pipe to pass through. The stator core 10 has a plurality of slots 19 formed at predetermined intervals on the inner circumferential portion in the circumferential direction, and the coil 11 is wound in units of, for example, three consecutive slots 19. The through hole 13 is preferably formed in the middle of adjacent slots 19 and near the outer periphery of the stator core 10 in a manner that does not affect the magnetic flux generated by electromagnetic induction due to the coil 11. The plurality of through holes 13 are arranged at approximately the same position in the radial direction Y of the stator core 10. The second cooling pipe passing through the through hole 13 only needs to be formed of a material having properties such as electrical insulation and heat resistance (such as metal, resin, etc.), and does not necessarily have to be a soft material.

[0046] If you refer to it again Figure 1 In order to prevent condensation caused by the refrigerant flowing in the first cooling pipe 12 and the second cooling pipe 14, the stator 1 is provided with the first cooling pipe 12 and the second cooling pipe 14. Before the refrigerant is supplied to the cooling pipe, the refrigerant temperature is preferably controlled to a temperature higher than the dew point. This can prevent corrosion and short circuit of the coil 11 in advance.

[0047] Figure 5 FIG. 2 shows a stator 2 in which a first cooling tube 12 and a second cooling tube 14 are arranged in a continuous tube. Figure 2 In the modified example of the stator 1 shown, a continuous tube (the first cooling tube 12 and the second cooling tube 14) goes back and forth between the coil ends 11a, 11b and the stator core 10. The stator 2 of this example has two continuous tubes, and the two tubes go back and forth alternately between the coil ends 11a, 11b and the stator core 10, and have two inlets IN1~IN2 and two outlets OUT1~OUT2. By forming the first cooling tube 12 and the second cooling tube 14 as a continuous tube, the inlets IN1~IN2 and outlets OUT1~OUT2 of the cooling tubes converge on the input side or the output side of the motor. As a result, the configuration space of the cooling tubes can be made relatively small.

[0048] exist Figure 2 and Figure 5 In the embodiment shown, the inlets IN1 and IN2 of the individual or continuous pipes may be arranged on the output side of the motor. Thus, since the cooler refrigerant is first supplied to the output side that is prone to heat, the cooling efficiency can be further improved.

[0049] Figure 6 2 shows a stator 3 in which a plurality of inlets and outlets of the first cooling tube 12 or the second cooling tube 14 are arranged at predetermined intervals in the circumferential direction of the stator core 10. The stator 3 of this example is Figure 5In the modified example of the stator 2 shown, four tubes alternately reciprocate between the coil ends 11a, 11b and the stator core 10, and have four inlets IN1 to IN4 and outlets OUT1 to OUT4. The inlets IN1 to IN2 of two tubes are arranged at, for example, 0° in the circumferential direction, and the inlets IN3 to IN4 of two tubes are arranged at, for example, 180° in the circumferential direction. Thus, since a cooler refrigerant is supplied every 180°, the cooling performance of the stator 3 can be improved.

[0050] Figure 7 FIG. 4 shows a stator 4 in which the first cooling tube 12 is wound in the circumferential direction along the coil ends 11a and 11b. The stator 4 of this example is Figure 2 In the modified example of the stator 1 shown, the first cooling pipe 12 and the second cooling pipe 14 are arranged as separate pipes. The first cooling pipe 12 of this example is different from the above in that it is wound in the circumferential direction along the bundle of coils at the coil ends 11a and 11b located on the input side and the output side. The first cooling pipe 12 is wound around the outer circumference of the coil ends 11a and 11b, but can also be wound around the inner circumference of the coil ends 11a and 11b. The first cooling pipe 12 has both the function of cooling the heated coil ends 11a and 11b and the function of fixing the shape of the coil 11 by tightly binding the bundle of coils 11 located at the coil ends 11a and 11b.

[0051] According to the above embodiment, since the first cooling pipe 12 is wound around the coil ends 11a and 11b, it is possible to efficiently remove heat generated by the stator 1. In addition, the first cooling pipe 12 can also have a tightening function for fixing the shape of the coil 11.

[0052] Although various embodiments have been described in this specification, the present invention is not limited to the above-described embodiments, and it should be recognized that various modifications can be made within the scope described in the claims.

Claims

1. A stator of an electric motor, characterized in that: The stator of the motor has: A cylindrical stator core; A coil wound around the stator core; a first cooling pipe wound around a coil end formed at an axial end of the stator core; A through hole is provided in the stator core in an axial direction; as well as a second cooling pipe, which passes through the through hole, Wherein, the first cooling pipe and the second cooling pipe are formed by continuous pipes, The continuous tube travels back and forth between the coil ends and the stator core, and an inlet and an outlet of the continuous tube converge at an input side or an output side of the motor.

2. The stator of the electric motor according to claim 1, characterized in that: The first cooling pipe is spirally wound around the bundle of the coil located at the coil end, or is wound in a circumferential direction along the bundle of the coil located at the coil end.

3. The stator of the electric motor according to claim 1 or 2, characterized in that: The first cooling pipe tightly binds the bundle of the coil located at the coil end portion to fix the shape of the coil.

4. The stator of the electric motor according to claim 1 or 2, characterized in that: The first cooling pipe is formed of a soft material.

5. The stator of the electric motor according to claim 1, characterized in that: The stator of the electric motor further includes a plurality of slots formed at predetermined intervals in the inner peripheral portion of the stator core, and the through hole is formed in the middle of the adjacent slots and in the vicinity of the outer peripheral portion of the stator core.

6. The stator of the electric motor according to claim 1, characterized in that: The inlet of the continuous tube is arranged on the output side of the motor.

7. The stator of the electric motor according to claim 1, characterized in that: A plurality of inlets and outlets of the first cooling pipe or the second cooling pipe are arranged at predetermined intervals in the circumferential direction of the stator core.

8. The stator of the electric motor according to claim 1, characterized in that: The stator of the electric motor further includes a cooling jacket disposed on an outer peripheral portion of the stator core, and a refrigerant supplied to the cooling jacket is shared with a refrigerant supplied to at least one of the first cooling pipe and the second cooling pipe.

9. The stator of the electric motor according to claim 8, characterized in that: The stator of the electric motor further includes a thermally conductive resin that fills a gap formed by the stator core, the coil, and the cooling jacket.

10. The stator of the electric motor according to claim 9, characterized in that: The thermally conductive resin is a molding resin or an impregnating resin.

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