JP2010068699A - Electric motor equipped with fitting unit for combining stator core and end covers - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electric motor at low cost which ensures that end covers are mounted without any mold leakage resin during injection of the mold resin and avoids outer diameter increase due to mounting of the end covers. <P>SOLUTION: The electric motor includes a coil 12, a stator core 10 for supporting the coil 12, end covers 22a, 22b mounted on the stator core 10 to cover coil end portions 13a, 13b of the coil 12 which are protruded from an end surface in the axial direction of the stator core 10, and a resin filler 14 for filling a space among the coil 12, the stator core 10 and the end covers 22a, 22b. The electric motor includes a stator 100a having fitting units 26a, 26b which are provided on the stator core 10 and the end covers 22a, 22b for combining the stator core 10 and the end covers 22a, 22b with one another through complementary fitting. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an electric motor. In particular, the present invention relates to an electric motor having a heat transfer member that exhausts heat generated from a coil.

  In order to increase the output without increasing the size of the electric motor, it is necessary to improve the exhaust heat efficiency of the heat generated from the coil. Therefore, many electric motors having a heat transfer member that efficiently exhausts heat generated from the coil to the outside have been devised. For example, the electric motor shown in Patent Document 1 has a coil end portion and a heat radiating plate integrated with a mold resin (resin filler) as a heat transfer member, and heat generated from the coil end portion is molded resin and Heat is exhausted to the outside through the heat sink.

  The electric motor shown in Patent Document 2 also has a cover at the coil end portion, and the covers are assembled from each other with a bolt from the outside of the stator core so that there is no gap.

JP 2008-178190 A JP 7-332237 A

  In order to exhaust heat generated from the coil, a structure in which a heat radiating plate manufactured as a single member is mounted on the outer peripheral surface of the stator has been devised as a conventional technique. When a single member heat sink is attached to the stator, there is no gap, so that the mold resin does not leak to the outside when the mold resin is injected. However, since the heat radiating plate is mounted not only on the coil end portion but also on the outer peripheral surface of the stator core that supports the coil, there has been a problem that the outer diameter of the motor is increased by the thickness of the heat radiating plate.

  To solve this problem, there is a method of dividing the heat sink and attaching the heat sink only to the end of the coil as in the electric motor shown in Patent Document 1. However, if the end face of the heat sink is simply brought into contact with the stator core to be joined and fixed, a gap may be generated at the joint between the heat sink and the stator core. When the gap is generated, the mold resin leaks to the outside when the mold resin is injected. In order to prevent the mold resin from leaking from the generated gap, it is conceivable to attach a case to the stator separately, but there remains a problem that the outer diameter of the electric motor increases due to the attached case.

  Further, as in the electric motor shown in Patent Document 2, there is a method in which an end cover, which is a heat radiating member, is fastened and fixed with bolts in order to prevent the generation of a gap. However, it is necessary to provide the end cover with a fastening portion for fastening the end cover with a bolt, and as a result, the outer diameter of the electric motor increases.

  Accordingly, in order to solve the above-mentioned problems, the present invention provides an electric motor at a low cost without the outer diameter being increased by the end cover while the end cover is fixed without the mold resin leaking when the mold resin is injected. The purpose is to do.

  To achieve the above object, the invention according to claim 1 covers a coil, a stator core that supports the coil, and a coil end portion of the coil that protrudes from the axial end surface of the stator core. And an end cover attached to the stator core, and a resin filler that fills a space between the coil and the stator core and the end cover. An electric motor is provided, which includes a fitting portion that is provided on the stator and that couples the stator core and the end cover to each other by complementary fitting.

  According to a second aspect of the present invention, in the electric motor according to the first aspect, the end cover has a cylindrical portion, and the fitting portion is an annular recess formed on the axial end surface of the stator core. And an annular edge portion of the cylindrical portion of the end cover fitted into the annular recess.

  The invention according to claim 3 is the electric motor according to claim 2, wherein the outer peripheral surface of the cylindrical portion of the end cover and the outer peripheral surface of the stator core are along the same virtual cylindrical surface. An electric motor is provided.

  According to a fourth aspect of the present invention, there is provided the electric motor according to the second or third aspect, wherein the end cover has a lid portion projecting inward of the cylindrical portion on the opposite side of the annular edge. .

  According to a fifth aspect of the present invention, in the electric motor according to any one of the first to fourth aspects, the fitting portion has a clearance fit fitting structure, and an adhesive is applied to the fitting portion. An electric motor is provided.

  A sixth aspect of the present invention provides the electric motor according to any one of the first to fourth aspects, wherein the electric motor has a fit-fitting structure.

  According to the first aspect of the present invention, since the stator core and the end cover are provided with the fitting portions and the stator core and the end cover are coupled to each other, a gap is hardly generated at the coupling portion. Therefore, even when mold resin (resin filler) is injected and filled into the space between the stator core and the end cover, leakage of the mold resin can be prevented. Furthermore, since the end cover is covered only on the coil end portion, it is not necessary to attach the end cover to the outer peripheral surface of the stator core. Therefore, the outer diameter of the electric motor does not increase due to the thickness of the end cover, and the electric motor can be downsized. Further, since a mold for preventing leakage of the mold resin is not required at the time of injection of the mold resin, it is possible to manufacture the electric motor at a low cost without requiring the cost necessary for mold manufacture.

  According to the invention of claim 2, the end cover includes a cylindrical portion, and the fitting portion includes an annular recess formed at an axial end portion of the stator core and an annular edge portion of the end cover. Is done. Therefore, it is difficult for a gap to be generated in the fitting portion, and the stator core and the end cover can be easily coupled and fitted.

  According to invention of Claim 3, the outer peripheral surface of a stator core and the outer peripheral surface of an end cover are arrange | positioned along the same virtual cylindrical surface. Therefore, when the electric motor is installed or incorporated in another machine or cooling means, a larger area of the outer peripheral surface of the electric motor can be brought into close contact with other equipment or cooling means. That is, both the outer peripheral surface of the stator iron core and the outer peripheral surface of the end cover can be brought into close contact with other machines and cooling means without generating a gap, and the exhaust heat efficiency can be improved.

  According to the invention of claim 4, a lid portion is provided on the opposite side of the annular edge portion so as to project inside the cylindrical portion. Therefore, the heat transfer path through the lid portion is increased and the exhaust heat efficiency is further increased. Further, by providing the lid portion, it is possible to reduce the manufacturing process without requiring a step of sealing the end portion of the electric motor when the mold resin is injected. That is, the manufacturing cost of the electric motor can be reduced, and the electric motor can be provided at a low cost.

  According to the invention of claim 5, since the fitting portion has a clearance fit fitting structure and the adhesive is disposed in the fitting portion, the gap generated by the deformation or expansion of the end cover can be filled. it can. Therefore, there is an effect that the mold resin hardly leaks from the fitting portion when the mold resin is injected.

  According to the invention of claim 6, the fitting portion has an interference fit fitting structure. Therefore, for example, when the end cover is fixed to the fitting portion of the stator core by shrink fitting, the end cover is cooled and contracted in the radial direction, so that the end cover can be fixed without generating a gap. Therefore, there is an effect that the mold resin hardly leaks from the fitting portion when the mold resin is injected.

  Embodiments of the present invention will be described below with reference to the accompanying drawings. In the following drawings, the same members are denoted by the same reference numerals. FIG. 1 is a cross-sectional view showing a configuration of a stator of an electric motor according to the present invention. FIG. 2 is an enlarged view of a portion B shown in FIG.

  First, the structure of the stator 100a of the electric motor of this embodiment is demonstrated using FIG. The stator 100a of the electric motor of the present embodiment includes a stator core 10, a coil 12, a mold resin 14, and end covers 22a and 22b. The stator 100a includes fitting portions 26a and 26b, and the fitting portions 26a and 26b couple the end covers 22a and 22b and the stator core 10 to each other.

  The stator core 10 is a cylindrical core and is manufactured by laminating annular magnetic steel plates. A hollow hole 11 is formed inside the stator core 10, and a jig or a motor rotor (not shown) used when pouring mold resin 14 (resin filler) into the hollow hole 11. Inserted.

  The stator core 10 supports the coil 12, and coil end portions 13 a and 13 b that are ends of the coil 12 protrude outward from the end face in the axial direction of the stator core 10. Also, as shown in FIG. 1, a lead wire 18 for supplying power to the coil 12 is led out from the end of the coil end portion 13a.

  The end covers 22a and 22b of this embodiment are cylindrical members and are formed of a metal or resin having high heat conductivity. The outer diameters of the end covers 22a and 22b are substantially the same as the outer diameter of the stator core 10, and the end covers 22a and 22b are attached to the stator core 10 so as to cover the coil end portions 13a and 13b.

  The mold resin 14 is injected, filled, and solidified into the space between the coil end portions 13a and 13b and the end covers 22a and 22b. The mold resin 14 and the end covers 22a and 22b are in close contact with each other on the outer peripheral surfaces 16a and 16b of the mold resin 14. Therefore, the heat generated from the coil end portions 13a and 13b is exhausted to the outside through the mold resin 14 and the end covers 22a and 22b. A method for injecting the mold resin 14 will be described later.

  Next, the fitting part 26a is demonstrated using FIG. Since the structure of the fitting part 26b is the same as that of the fitting part 26a, description is abbreviate | omitted. The fitting portion 26a includes an annular recess formed on the axial end surface of the stator core 10 and a cylindrical annular end portion of the end cover 22a fitted into the annular recess. The annular recess of the fitting portion 26 a of the present embodiment is a stepped portion formed by cutting the stator core 10 and reducing the end of the stator core 10 in the radial direction C. The length D for reducing the diameter of the stator core 10 in the radial direction C is substantially the same as the thickness E of the end cover 22a. That is, the outer diameter W2 of the end portion of the reduced stator iron core is substantially the same as the inner diameter H2 of the end cover 22a (see FIG. 1), and the annular end portion of the end cover 22a is fitted into the annular recess. Thus, the end cover 22a and the stator core 10 are coupled and fitted together.

  It will be described that the mold resin is less likely to leak when the stator 100a includes the fitting portion 26a. As shown in FIG. 2, when the stator core 10 and the end cover 22a are fitted in the fitting portion 26a, the end surface 27a of the end cover 22a and the inner peripheral surface 28a of the end portion of the end cover 22a are fixed to the stator. Fixed in contact with the iron core 10. The fixing method will be described later.

  For example, as in the electric motor shown in Patent Document 1, when the end cover is fixed by contacting only the end face of the end cover with the stator core, once a gap occurs at the joint portion, the mold resin is removed from the gap. Leak outside. On the other hand, the end cover 22a of the present embodiment is fixed in contact with the stator core 10 on the inner peripheral surface 28a at the end of the end cover 22a in addition to the end surface 27a of the end cover by fitting. Since the portion where the end cover 22a and the stator core 10 are in contact with each other is widened, the end cover 22a can be more firmly fixed. Furthermore, since it is fitted in the fitting part 26a, one of the inner peripheral surface 28a and the end surface 27a is in contact with no gap. That is, even when a gap is generated on one of the inner peripheral surface 28a and the end surface 27a, the mold resin is prevented from leaking by the other, so that the mold resin is difficult to leak.

  On the other hand, when the end cover is joined to the end face of the stator core without providing the fitting portion 26a as in this embodiment, there is also a method of using a mold that covers the outer peripheral surface of the electric motor in order to prevent leakage of the mold resin. Conceivable. That is, in the mold, the stator core and the end cover are simultaneously put and the mold resin is injected to assemble the electric motor. However, since the production of the mold is expensive, it leads to high costs when assembling the electric motor. Since the stator 100a of the electric motor of this embodiment does not require a mold when injecting the mold resin 14, it is possible to provide an electric motor filled with the mold resin at a low cost.

  In general, the electric motor is installed or incorporated in another machine or cooling means. Therefore, when the outer peripheral surface of the electric motor comes into close contact with other machines and cooling means, heat generated from the electric motor is transferred to other devices and cooling means. Therefore, the exhaust heat efficiency of the motor increases as the area where the motor is in close contact with other devices and cooling means increases. That is, it is better that there is no step on the outer peripheral surface of the electric motor and no gap is generated between other machines and cooling means. In the case where the end cover is joined to the stator core without having a fitting portion as in the prior art, the end cover may be joined while being displaced in the left-right direction, for example. Therefore, even if the outer diameter of the end cover 22a and the outer diameter of the stator core 10 are the same, there may be a step in the joint portion.

  Since this embodiment is provided with the fitting part 26a, the end cover 22a is fixed to the stator core 10 without slipping. In addition, as described above, in the present embodiment, the length D for reducing the diameter of the stator core 10 in the radial direction is substantially the same as the thickness E of the end cover 22a. The outer peripheral surface 32a of the cover 22a forms a surface having substantially no step. That is, the outer peripheral surface 31 of the stator core 10 and the outer peripheral surface 32a of the end cover 22a are arranged along the same virtual cylindrical surface. Therefore, when it is installed or built in another machine or cooling means, the outer peripheral surface of the electric motor can be brought into close contact with the other machine or cooling means without generating a gap due to a step. Therefore, it is possible to provide an electric motor having better exhaust heat efficiency.

  Furthermore, since the end cover 22a is in contact with the stator core 10 on the inner peripheral surface 28a of the end cover 22a, the end cover 22a is not easily deformed even when an external force is applied in the radial direction C. Therefore, even after the end cover 22a and the stator core 10 are fitted and fixed, there is no step between the outer peripheral surface 32a of the end cover 22a and the outer peripheral surface 31 of the stator core 10, and the virtual cylindrical surface is maintained. Is possible.

  Next, a method for fixing the end covers 22a and 22b to the fitting portions 26a and 26b will be described. The fitting portions 26a and 26b of the present embodiment have a so-called clearance fit fitting structure. Therefore, it is possible to fix the end covers 22a and 22b by disposing and bonding an adhesive to the fitting portions 26a and 26b. By using an adhesive, for example, gaps generated by deformation or expansion of the end covers 22a and 22b can be filled, and leakage of the mold resin can be prevented.

  Since the fitting portions 26a and 26b of the present embodiment have a tight fit fitting structure, when the end covers 22a and 22b are made of metal, they can be fixed by shrink fitting. Since the heated end covers 22a and 22b are fixed by cooling and contracting in the radial direction C, the end covers 22a and 22b are firmly fixed without generating a gap in the fitting portions 26a and 26b. Can do.

  Next, a method for injecting the mold resin 14 will be described with reference to FIG. FIG. 3 is a cross-sectional view showing a state before the mold resin 14 is injected into the stator 100a of the electric motor according to the present embodiment. The stator 100a shown in FIG. 3 is a state in which the end covers 22a and 22b are fixed to the stator core 10 by shrink fitting or an adhesive. As described above, the hollow hole 11 is formed at the center of the stator core 10, and a jig 40 is inserted into the hollow hole 11 as a preparation stage for injecting the mold resin 14. The lower end portion of the stator 100a is sealed with a sealing member 42 attached.

  In this state, fluid mold resin 14 is injected from the upper end of stator 10 into the space between end covers 22a, 22b and coil end portions 13a, 13b. Further, the mold resin 14 is injected into a space between the coil end portion 13b and the end cover 22b through a groove (not shown) in which the coil 12 of the stator core 10 is supported. After the mold resin 14 is filled and solidified, the jig 40 and the sealing member 42 are removed to complete the stator 100a shown in FIG.

  Another example of the stator of the electric motor according to this embodiment will be described with reference to FIG. FIG. 4 is a cross-sectional view showing another configuration example of the stator. The stator 100b has substantially the same configuration as the stator 100a shown in FIG. 1, but is further provided at both end portions of the stator 100b and annular end portions of the end covers 22a and 22b fitted into the annular recesses of the coil end 10. The point which has lid parts 23a and 23b in the edge part (henceforth the distal ends 29a and 29b) located in the other side is different.

  The lid portions 23a and 23b protrude from the distal ends 29a and 29b of the end covers 22a and 22b toward the inside of the cylindrical portions of the end covers 22a and 22b. It can also be said that the lid portions 23a and 23b are provided to extend radially inward from the distal ends 29a and 29b. Therefore, the cross section of the lid portions 23a, 23b and the cylindrical portions of the end covers 22a, 22b is L-shaped (see FIG. 4).

  The mold resin 14 is filled in the space between the coil end portions 13a and 13b and the end covers 22a and 22b, like the stator 100a of FIG. The mold resin 14 of the stator 100b shown in FIG. 4 is further filled in close contact with the inner surfaces of the lid portions 23a and 23b. Since the inner surfaces of the lid portions 23a and 23b are in close contact with the mold resin 14, the stator 100b discharges the heat generated from the coil end portions 13a and 13b from the lid portions 23a and 23b via the mold resin 14. Is possible. That is, since the path for exhausting heat increases, the exhaust heat efficiency of the stator 100b is improved.

  The lead wire 18 is led out through a lead wire hole 19 formed in the lid portion 23a. Further, the mold resin 14 is injected into the end covers 22 a and 22 b through the lead wire holes 19.

  In addition, when the mold resin 14 is injected into the stator 100a of FIG. 1, it was sealed by the sealing member 42 attached to the lower end of the stator 100a as shown in FIG. By having it, it is not necessary. That is, the step of attaching the sealing member 42 to the end portion of the stator and the step of removing the sealing member 42 after the mold resin 14 is solidified can be omitted.

  The embodiments of the present invention have been described above with reference to the accompanying drawings. In addition, this invention is not limited to the said embodiment, In the range which does not deviate from the main point of this invention, it can deform | transform and implement variously. For example, in this embodiment, the fitting portion is provided with an annular recess formed by cutting the stator core and reducing the diameter, but the fitting portion is made of a magnetic steel plate punched out to a small diameter. You may prepare by arrange | positioning at the edge part. Further, the fitting portion may be configured such that an annular groove portion is provided on the axial end surface of the stator core and the annular edge portion of the end cover is fitted. Further, in the stator 100b of FIG. 4, the lid portions are provided at both ends of the stator. However, when the purpose of omitting the attaching and removing steps of the sealing member is to be performed, the lower side is fixed at the time of injection. You may provide a cover part only in the edge part of a child.

It is sectional drawing which shows the structural example of the stator of the electric motor which concerns on this invention. It is an enlarged view of the B section shown in FIG. It is a structural example of the stator of the electric motor which concerns on this invention, Comprising: It is sectional drawing which shows the state before filling a stator with mold resin. It is sectional drawing which shows another structural example of the stator of the electric motor which concerns on this invention.

Explanation of symbols

100a, 100b Stator 10 Stator core 11 Hollow hole 12 Coil 13a, 13b Coil end portion 14 Mold resin 16a, 16b Mold resin outer peripheral surface 18 Lead wire 19 Lead wire hole 22a, 22b End cover 23a, 23b Lid portion 26a , 26b Fitting portions 29a, 29b Distal end 31 Outer peripheral surface of stator core 32a, 32b Outer peripheral surface of end cover 40 Jig 42 Sealing member 50 Axis

Claims (6)

A coil, a stator core that supports the coil, an end cover that is attached to the stator core so as to cover a coil end portion of the coil that protrudes from the axial end surface of the stator core, and the coil and the fixed In an electric motor comprising a resin filler that fills a space between a core and the end cover,
An electric motor comprising a fitting portion that is provided on the stator core and the end cover and couples the stator core and the end cover to each other by complementary fitting.   The end cover has a cylindrical portion, and the fitting portion includes an annular recess formed in the axial end surface of the stator core, and an annular recess of the end cover that is fitted into the annular recess. The electric motor according to claim 1, comprising an annular edge.   The electric motor according to claim 2, wherein an outer peripheral surface of the cylindrical portion of the end cover and an outer peripheral surface of the stator core are disposed along the same virtual cylindrical surface.   4. The electric motor according to claim 2, wherein the end cover includes a lid portion that protrudes inside the cylindrical portion on the opposite side of the annular edge portion.   The electric motor according to any one of claims 1 to 4, wherein the fitting portion has a clearance fit fitting structure, and an adhesive is disposed in the fitting portion.   The electric motor according to any one of claims 1 to 4, wherein the fitting portion has an interference fit fitting structure.

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