Stator and method for manufacturing stator

Abstract

The present disclosure is a stator comprising: a core; a coil having a coil end portion that protrudes from an axial end portion of the core; a cylindrical member that is in contact with the end portion of the core and covers the periphery of the coil end portion; and a molded resin that is filled in an interior space of the cylindrical member. The stator comprises an elastic member that is disposed between the cylindrical member and the molded resin, and is in close contact with the cylindrical member and the molded resin.

Description

Stator and method for manufacturing the same

[0001] The present disclosure relates to a stator and a method for manufacturing a stator.

[0002] Generally, a motor is known that includes a stator having a coil and a rotor rotatably disposed inside the stator. In order to improve the insulation performance and cooling performance of the coil, a cylindrical member that covers the coil end portion of the coil may be filled with a molding resin (for example, see JP 2004-120923 A).

[0003] Furthermore, there are cases where the cylindrical member is processed after the molding resin is filled into the inner space of the cylindrical member, and in such cases, it is desirable to prevent dimensional defects in the processed cylindrical member.

[0004] A first aspect of the present disclosure is a stator having a core, a coil provided on the core and having a coil end portion protruding from an axial end of the core, a cylindrical member contacting the end of the core and covering the outer periphery of the coil end portion, and a molded resin filled into the interior of the cylindrical member, and including an elastic member disposed between the cylindrical member and the molded resin and in close contact with each of the cylindrical member and the molded resin.

[0005] A second aspect of the present disclosure is a method for manufacturing a stator, comprising: a filling step of filling molten resin into the interior of cylindrical members attached to both axial ends of a core; a cooling step of cooling the molten resin to harden the molten resin; and a cutting step of cutting the outer surface of the cylindrical member until the difference in level between the outer surface of the cylindrical member and the outer surface of the core is equal to or less than an allowable value, wherein each of the cylindrical members before being filled with the molten resin in the filling step contacts an end of the core in the axial direction and covers the outer periphery of a coil end portion protruding from the end, and an elastic member is bonded to the inner surface of each of the cylindrical members, and the cutting in the cutting step is performed in a state where the elastic member bonded to the inner surface of the cylindrical member is in close contact with the molded resin obtained by hardening the molten resin.

[0006] FIG. 1 is a cross-sectional view of a stator of a motor according to an embodiment. FIG. 2 is a flowchart showing the procedure of a manufacturing process for a stator. FIG. 3 is a cross-sectional view showing a state after an attachment process. FIG. 4 is a view showing a cylindrical member attached in the attachment process. FIG. 5 is a cross-sectional view showing a state after a filling process. FIG. 6 is a view showing a cylindrical member of Modified Example 1. FIG. 7 is a view showing a cylindrical member of Modified Example 2. FIG. 8 is a view showing a cylindrical member of Modified Example 3. FIG. 9 is a cross-sectional view of a stator of a motor according to Modified Example 5. FIG. 10 is a cross-sectional view showing a state after the attachment process in Modified Example 5.

[0007] The molding resin filled into the inner space of a cylindrical member that covers the coil end portion of a coil is in a molten state when filling the inner space and hardens after filling the inner space. However, the molding resin may shrink when transitioning from a molten state to a hardened state. When the molding resin shrinks, a gap occurs between the cylindrical member and the molding resin. In this case, the gap causes dimensional defects in the processed cylindrical member. The following disclosure is an embodiment for suppressing the occurrence of dimensional defects in the processed cylindrical member.

[0008] 1 is a cross-sectional view of a stator 10 of a motor according to an embodiment. The stator 10 includes a core 12, a coil 14, a cylindrical member 16, a molded resin 18, and an elastic member 20.

[0009] The core 12 is composed of, for example, a plurality of magnetic steel plates 12a stacked in the axial direction DA. The axial direction DA is the direction in which the axial center AX of the core 12 extends. The axial center AX of the core 12 coincides with the rotation axis of the stator 10. The core 12 is also referred to as an iron core. The core 12 has a cylindrical core body and a plurality of teeth that protrude from the core body inward in the radial direction DB of the core 12. A coil 14 is provided on each tooth. The coil 14 may be wound around the teeth.

[0010] The coil 14 has a coil end portion 14E. The coil end portion 14E protrudes from one end 12E1 of the core 12 and the other end 12E2 of the core 12. The one end 12E1 and the other end 12E2 of the core 12 are each the end 12E in the axial direction DA of the core 12. A power line LN is connected to the coil 14.

[0011] The cylindrical member 16 is a member formed in a cylindrical shape. The cylindrical member 16 is formed of, for example, aluminum or an iron-based material. The cylindrical member 16 is arranged at the end 12E of the core 12 in the axial direction DA. The cylindrical member 16 arranged at one end 12E1 of the core 12 may be referred to as the cylindrical member 16A. The cylindrical member 16 arranged at the other end 12E2 of the core 12 may be referred to as the cylindrical member 16B. The cylindrical members 16A and 16B have substantially the same configuration.

[0012] The cylindrical member 16 is in contact with an end 12E in the axial direction DA of the core 12. The cylindrical member 16 surrounds the coil end portion 14E from the outside and covers the outer periphery of the coil end portion 14E.

[0013] The molding resin 18 is disposed inside the cylindrical member 16. The molding resin 18 fills the inner space of the cylindrical member 16. After filling, the molding resin 18 transitions from a molten state to a hardened state.

[0014] The elastic member 20 is disposed between the cylindrical member 16 and the molded resin 18. In the present embodiment, the elastic member 20 has a ring shape. The elastic member 20 is disposed around the entire circumferential direction of the inner circumferential surface of the cylindrical member 16, at the end of the cylindrical member 16 opposite the core 12 side. The elastic member 20 is preferably made of an insulating material to ensure insulation between the coil 14 and the cylindrical member 16.

[0015] The elastic member 20 is in close contact with both the cylindrical member 16 and the molded resin 18. In this embodiment, the elastic member 20 has adhesive layers 20LY on both sides. The adhesive layer 20LY on one side of the elastic member 20 adheres to the inner surface of the cylindrical member 16, and the adhesive layer 20LY on the other side adheres to the molded resin 18. The elastic member 20 may be double-sided tape or an adhesive. The adhesive layer 20LY may also be an adhesive.

[0016] Therefore, even if the molded resin 18 shrinks in the radial direction of the cylindrical member 16 when it hardens from a molten state, no gap is created between the molded resin 18 and the elastic member 20. In other words, as the molded resin 18 shrinks, the elastic member 20 expands in the radial direction of the cylindrical member 16, so no gap is created between the molded resin 18 and the cylindrical member 16. Therefore, the close contact between the cylindrical member 16 and the molded resin 18 is maintained.

[0017] In this embodiment, the elastic member 20 is disposed over the entire circumferential direction of the cylindrical member 16. Therefore, the elastic member 20 can be firmly maintained in close contact with both the cylindrical member 16 and the molded resin 18.

[0018] 2 to 5, a method for manufacturing the stator 10 will be described. The method for manufacturing the stator 10 includes a mounting step P1, a filling step P2, a cooling step P3, and a cutting step P4 (see FIG. 2).

[0019] The attachment process P1 is a process of attaching the cylindrical member 16 to the core 12 (see FIG. 3 ). In the attachment process P1, the cylindrical member 16A is fixed to one end 12E1 of the core 12 by, for example, shrink fitting. In this case, the cylindrical member 16A covers the outer periphery of the coil end portion 14E protruding from one end 12E1 of the core 12. Also in the attachment process P1, the cylindrical member 16B is fixed to the other end 12E2 of the core 12 by, for example, shrink fitting. In this case, the cylindrical member 16B covers the outer periphery of the coil end portion 14E protruding from the other end 12E2 of the core 12.

[0020] An elastic member 20 is bonded to the inner peripheral surface of the cylindrical member 16 attached to the core 12 (see FIG. 4). The elastic member 20 may be bonded before or after the cylindrical member 16 is fixed to the core 12.

[0021] The filling step P2 is a step of filling the inner space of the cylindrical member 16 attached to the core 12 with molten resin 22 (see FIG. 3). The molten resin 22 is obtained by heating and liquefying the molding resin 18. Examples of such resins include thermoplastic resins. In the filling step P2, the molten resin 22 is poured into the inner space of the cylindrical member 16, for example, from the cylindrical member 16A. In this case, the space AR formed in the core 12 for disposing a rotor (not shown) and the opening 18OP of the cylindrical member 16B are blocked.

[0022] The molten resin 22 poured from the cylindrical member 16A flows between the teeth of the core 12 and is stored in the inner space of the cylindrical member 16B. When the molten resin 22 fills the inner spaces of the cylindrical members 16A and 16B (see FIG. 5), the coil end portion 14E and the connection portion between the coil end portion 14E and the power line LN are immersed in the molten resin 22.

[0023] The cooling process P3 is a process for cooling and hardening the molten resin 22. In the cooling process P3, the process waits until the molten resin 22 hardens. The molten resin 22 hardens and transforms into the molded resin 18. The molded resin 18 and the elastic member 20 are bonded together. Therefore, even if the molded resin 18 shrinks during the hardening process, the elastic member 20 follows the shrinkage and maintains the close contact between the molded resin 18 and the cylindrical member 16. This prevents the molded resin 18 and the cylindrical member 16 from separating and forming a gap between them.

[0024] The cutting process P4 is a process for processing the cylindrical member 16. In the cutting process P4, the outer circumferential surface of the cylindrical member 16 is cut until the step ST (see FIG. 5) between the outer circumferential surface of the cylindrical member 16 and the outer circumferential surface of the core 12 is within the allowable value. Preferably, cutting is performed until the step ST becomes zero. In the cutting process P4, for example, a lathe is used. When the cutting process P4 is completed, the stator 10 is obtained (see FIG. 1). In this case, the outer circumferential surface of the cylindrical member 16 and the outer circumferential surface of the core 12 are generally flush with each other.

[0025] Even if the molded resin 18 shrinks in the cooling step P3, the elastic member 20 maintains the tight contact between the molded resin 18 and the cylindrical member 16. Therefore, the cutting process for the cylindrical member 16 can be stabilized compared to when a gap occurs between the molded resin 18 and the cylindrical member 16 due to shrinkage of the molded resin 18. As a result, it is possible to prevent dimensional defects in the cylindrical member 16 and a reduction in yield.

[0026] The above-described embodiments may be modified as follows. In the following modifications, explanations that overlap with the embodiments will be omitted. In addition, in the drawings used in the following modifications, the same reference numerals are used for the same components as those described in the embodiments.

[0027] 6 is a diagram showing a cylindrical member 16 of Modification 1. In this modification, a plurality of elastic members 20 are adhered to the inner circumferential surface of the cylindrical member 16 that is attached to the core 12 in the attachment step P1.

[0028] The multiple elastic members 20 are arranged at intervals in the axial direction DA of the cylindrical member 16. Each elastic member 20 has a ring shape. Each elastic member 20 is arranged around the entire circumferential direction of the inner circumferential surface of the cylindrical member 16.

[0029] In this modification, the contact area of ​​the elastic member 20 with both the cylindrical member 16 and the molded resin 18 is increased compared to the embodiment. Therefore, the elastic member 20 can be firmly maintained in close contact with both the cylindrical member 16 and the molded resin 18.

[0030] 7 is a diagram showing a cylindrical member 16 according to Modification 2. In this modification, a plurality of elastic members 20 are bonded to the inner circumferential surface of the cylindrical member 16 that is attached to the core 12 in the attachment step P1.

[0031] The multiple elastic members 20 are arranged at intervals in both the axial direction DA of the cylindrical member 16 and the circumferential direction of the cylindrical member 16. Each elastic member 20 has a hemispherical outer shape. The surface of each elastic member 20 that comes into contact with the inner circumferential surface of the cylindrical member 16 is formed into a flat surface.

[0032] Therefore, in this modification, the contact area (first contact area) of the elastic member 20 with the cylindrical member 16 can be reduced, while the contact area (second contact area) of the elastic member 20 with the molded resin 18 can be made larger than the first contact area. As a result, adhesion with the molded resin 18 that hardens from a molten state can be improved. Furthermore, in this modification, the concentration of stress generated in the elastic member 20 due to the contraction of the molded resin 18 can be reduced.

[0033] 8 is a diagram showing a cylindrical member 16 according to Modification 3. In this modification, a plurality of elastic members 20 are bonded to the inner circumferential surface of the cylindrical member 16 that is attached to the core 12 in the attachment step P1.

[0034] The multiple elastic members 20 are arranged at intervals around the circumferential direction of the cylindrical member 16. Each elastic member 20 extends along the axial direction DA of the cylindrical member 16. Each elastic member 20 has multiple polygonal portions 20A with a polygonal outer shape. The multiple polygonal portions 20A are connected along the axial direction DA of the cylindrical member 16. Compared to a case where the polygonal portions 20A are not formed and the elastic members 20 extend straight along the axial direction DA of the cylindrical member 16, the contact area of ​​the elastic members 20 with the molded resin 18 is increased. As a result, adhesion with the molded resin 18 that hardens from a molten state can be improved.

[0035] A through hole TH is formed in each polygonal portion 20A. One through hole TH is provided for each polygonal portion 20A. In other words, each polygonal portion 20A has a ring shape. Compared to a case where no through hole TH is formed in the elastic member 20, the contact area between the elastic member 20 and the molded resin 18 is increased. As a result, it is possible to improve adhesion with the molded resin 18 as it hardens from a molten state.

[0036] (Modification 4) The elastic member 20 may be bonded to the entire inner circumferential surface of the cylindrical member 16 that is attached to the core 12 in the attachment step P1.

[0037] 9 is a cross-sectional view of the stator 10 of a motor according to Modification 5. The elastic member 20 may be disposed between the surface of the coil end portion 14E and the molded resin 18, in addition to being disposed between the cylindrical member 16 and the molded resin 18. The elastic member 20 is also in close contact with both the coil end portion 14E and the molded resin 18. As a result, the cutting process on the cylindrical member 16 can be made even more stable.

[0038] 10 , in the attachment step P1, the elastic member 20 is adhered to the inner circumferential surface of the cylindrical member 16 and the surface of the coil end portion 14E. The elastic member 20 may be adhered before the cylindrical member 16 is fixed to the core 12, or may be adhered after the cylindrical member 16 is fixed to the core 12.

[0039] Furthermore, in this modified example, it is preferable to place an elastic member 20 between a portion of the surface of the coil end portion 14E and the molded resin 18. This is because placing the elastic member 20 between the entire surface of the coil end portion 14E and the molded resin 18 slows down the penetration of the molten resin 22 into the interior of the coil end portion 14E. Note that Figures 9 and 10 show the case where the elastic member 20 is placed between the outer periphery of the surface of the coil end portion 14E and the molded resin 18. In this case, in the filling step P2, the molten resin 22 quickly penetrates from the inner periphery of the surface of the coil end portion 14E into the interior of the coil end portion 14E.

[0040] (Variation 6) When a liquid adhesive is used, the elastic member 20 may be provided after the cooling step P3. In this case, the elastic member 20 is not bonded to the inner circumferential surface of the cylindrical member 16 in the attachment step P1. Furthermore, after the cooling step P3 and before the cutting step P4, a liquid adhesive is filled into the gap between the cylindrical member 16 and the molded resin 18 obtained by hardening the molten resin 22 in the cooling step P3. Once the adhesive has hardened, the cutting step P4 is performed. In other words, the cutting of the cylindrical member 16 is performed in a state in which the cylindrical member 16 and the molded resin 18 are bonded together by the adhesive. Note that in this variation, the adhesive may also be filled into the gap between the surface of the coil end portion 14E and the molded resin 18.

[0041] (Modification 7) The above modifications may be combined as appropriate within a range that does not cause contradictions.

[0042] [Correction based on Rule 91 22.03.2024] As described above, according to the above-described embodiment (including the modified example), the elastic member 20 maintains close contact between the molded resin 18 and the cylindrical member 16. In addition, the elastic member 20 may maintain close contact between the molded resin 18 and the coil end portion 14E. This can prevent dimensional defects in the cylindrical member 16 from occurring.

[0043] The following additional notes are further disclosed regarding the above embodiment.

[0044] (Supplementary Note 1) The present disclosure relates to a stator (10) having a core (12), a coil (14) provided on the core and having a coil end portion (14E) protruding from an end (12E) of the core in an axial direction (DA) of the core, a cylindrical member (16) in contact with the end of the core and covering the outer periphery of the coil end portion, and a molded resin (18) filled into the interior of the cylindrical member, and further comprising an elastic member (20) disposed between the cylindrical member and the molded resin and in close contact with each of the cylindrical member and the molded resin.

[0045] (Supplementary Note 2) In the stator according to Supplementary Note 1, the elastic member may have an adhesive layer (20LY) on a surface facing the molding resin and a surface facing the cylindrical member.

[0046] (Supplementary Note 3) In the stator according to Supplementary Note 1 or 2, the elastic member may be disposed over the entire circumferential circumference of the cylindrical member.

[0047] (Supplementary Note 4) In the stator described in any one of Supplementary Notes 1 to 3, the elastic member may be disposed between at least a portion of a surface of the coil end portion and the molding resin, and may be in close contact with both the coil end portion and the molding resin.

[0048] (Supplementary Note 5) In the stator according to Supplementary Note 3 or 4, a plurality of the elastic members may be provided, and the elastic members may be arranged at intervals in the axial direction.

[0049] (Supplementary Note 6) The stator according to Supplementary Note 1 or 2 may include a plurality of the elastic members, and the plurality of elastic members may be arranged at intervals in the circumferential direction of the cylindrical member.

[0050] (Supplementary Note 7) In the stator according to Supplementary Note 6, the plurality of elastic members may be arranged at intervals in the axial direction.

[0051] (Appendix 8) A method for manufacturing a stator includes a filling step of filling molten resin (22) into the inner space of a cylindrical member attached to each of both axial ends of a core, a cooling step of cooling the molten resin to harden the molten resin, and a cutting step of cutting the outer circumferential surface of the cylindrical member until a difference in level between the outer circumferential surface of the cylindrical member and the outer circumferential surface of the core becomes equal to or less than an allowable value, wherein each of the cylindrical members before being filled with the molten resin in the filling step is in contact with an end of the core in the axial direction and covers the outer periphery of a coil end portion protruding from the end, and an elastic member is bonded to the inner surface of each of the cylindrical members, and the cutting in the cutting step is performed in a state where the elastic member bonded to the inner surface of the cylindrical member is in close contact with molded resin obtained by hardening the molten resin.

[0052] (Appendix 9) In the method for manufacturing a stator described in Appendix 8, the elastic member before being filled with the molten resin in the filling step may also be adhered to the surface of the coil end portion, and the cutting in the cutting step may be performed in a state where the elastic member adhered to the inner surface of the cylindrical member and the surface of the coil end portion is in close contact with the molded resin.

[0053] (Appendix 10) In the method for manufacturing a stator according to Appendix 8 or 9, the elastic member may have an adhesive layer on a surface facing the molded resin, and the cutting in the cutting step may be performed in a state where the elastic member is also adhered to the molded resin.

[0054] (Appendix 11) A method for manufacturing a stator includes the steps of: filling molten resin into the interior of cylindrical members attached to both axial ends of a core; cooling the molten resin to harden the molten resin; and cutting the outer circumferential surfaces of the cylindrical members; after the cooling step, adhesive is filled into gaps between each of the cylindrical members that contact the axial end of the core and cover the outer peripheries of the coil end portions protruding from the end, and molded resin obtained by hardening the molten resin, and the cylindrical members and the molded resin are bonded together by the adhesive, and the cutting step is carried out.

[0055] (Appendix 12) In the method for manufacturing a stator described in Appendix 11, the adhesive may also be filled into gaps between at least a portion of the surface of the coil end portion and the molding resin, and the cutting step may be performed in a state in which the cylindrical member and the coil end portion are each adhered to the molding resin.

[0056] Although the present disclosure has been described in detail, the present disclosure is not limited to the individual embodiments described above. Various additions, substitutions, modifications, partial deletions, etc. are possible in these embodiments without departing from the gist of the present disclosure or the spirit of the present disclosure derived from the content of the claims and their equivalents. These embodiments can also be implemented in combination. For example, in the above-described embodiments, the order of each operation and the order of each process are shown as examples and are not limited to these. The same applies when numerical values ​​or mathematical expressions are used in the description of the above-described embodiments.

[0057] REFERENCE SIGNS LIST 10 stator 12 core 14 coil 14E coil end portion 16 cylindrical member 18 molded resin 20 elastic member 22 molten resin

Claims

1. A stator comprising: a core; a coil provided in the core and having a coil end portion protruding from an end portion of the core in an axial direction; a cylindrical member in contact with the end portion of the core and covering an outer periphery of the coil end portion; and a molding resin filled into an inner space of the cylindrical member, The stator includes an elastic member disposed between the cylindrical member and the molding resin, and in close contact with both the cylindrical member and the molding resin.

2. 2. The stator according to claim 1, The elastic member has an adhesive layer on a surface facing the molding resin and a surface facing the cylindrical member.

3. 3. The stator according to claim 1 or 2, The elastic member is disposed around the entire circumferential direction of the cylindrical member.

4. 2. The stator according to claim 1, The stator further includes another elastic member that is disposed between at least a portion of a surface of the coil end portion and the molding resin, and that is in close contact with both the coil end portion and the molding resin.

5. 4. The stator according to claim 3, A plurality of the elastic members are provided, The plurality of elastic members are arranged at intervals in the axial direction of the stator.

6. 3. The stator according to claim 1 or 2, A plurality of the elastic members are provided, The plurality of elastic members are arranged at intervals in the circumferential direction of the cylindrical member.

7. 7. The stator according to claim 6, The plurality of elastic members are arranged at intervals in the axial direction of the stator.

8. A method for manufacturing a stator, comprising: a filling step of filling molten resin into the inner space of cylindrical members attached to both ends of the core in the axial direction; a cooling step of cooling the molten resin to harden the molten resin; a cutting step of cutting the outer circumferential surface of the cylindrical member until a step between the outer circumferential surface of the cylindrical member and the outer circumferential surface of the core becomes equal to or less than an allowable value; Including, each of the cylindrical members before being filled with the molten resin in the filling step contacts an end of the core in the axial direction and covers an outer periphery of a coil end portion protruding from the end, and an elastic member is bonded to an inner surface of each of the cylindrical members; A method for manufacturing a stator, wherein the cutting in the cutting step is performed in a state in which the elastic member adhered to the inner surface of the cylindrical member is in close contact with the molded resin obtained by hardening the molten resin.