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EP-4080742-B1 - MOLDED MOTOR PRODUCTION METHOD, AND MOLDED MOTOR

EP4080742B1EP 4080742 B1EP4080742 B1EP 4080742B1EP-4080742-B1

Inventors

  • NANBU, YASUO
  • AMAYA, TAKANORI
  • KOBAYASHI, EIJI
  • KAWABATA, Nobuhiro

Dates

Publication Date
20260506
Application Date
20201208

Claims (12)

  1. A method of manufacturing a molded motor (1), the method comprising: disposing, in a mold (100), a stator including a stator core (11) and a coil (12) wound around the stator core (11), and an inner metal member (40) that covers an outer side of the stator (10); and forming a molded resin (30) by injecting a liquid resin (30L) in a circumferential direction (Z) into the mold (100) through a resin injection portion provided in the mold (100), and curing the liquid resin, wherein the resin injection portion (100G) is located in a radial direction (Y) of the molded resin (30) after molding in which the molded resin after molding is orthogonal to an axial direction (X) of a central axis (C) of a rotating shaft (21) of the molded motor (1), wherein the molded resin (30) after molding includes a protruding portion (32) protruding outward in the radial direction (Y) from an outer surface of a main body (31), and wherein the resin injection portion is provided in a portion corresponding to the protruding portion so that the liquid resin flows around an entire circumferential direction (Z) which orbits the central axis (C).
  2. The method of manufacturing the molded motor (1) according to Claim 1, wherein the stator is pressed by a pin from an upper side to a lower side in a vertical direction during injection of the liquid resin.
  3. The method of manufacturing the molded motor (1) according to Claim 1 or 2, wherein the inner metal member (40) includes, in the radial direction (Y), a first portion located outside the stator, and a second portion located outside the stator and having a distance to the rotating shaft smaller than a distance from the first portion to the rotating shaft.
  4. The method of manufacturing the molded motor (1) according to Claim 3, wherein the coil (12) includes a coil end protruding from the stator core (11) in a direction along the central axis direction (X), the first portion faces the coil end, and the second portion faces the stator core (11).
  5. A molded motor (1) comprising: a stator including a stator core (11), and a coil (12) wound around the stator core (11); a rotor disposed opposite to the stator and including a rotating shaft (21) extending in an axial direction (X) of a central axis (C) of the rotating shaft (21); a molded resin (30) covering the stator and including a protruding portion (32) protruding outward in the radial direction (Y) from an outer surface of a main body (31); and an inner metal member (40) including a first portion located outside the stator in a radial direction (Y) orthogonal to the central axis direction (X), and a second portion located outside the stator in the radial direction (Y) and having a distance to the rotating shaft smaller than a distance from the first portion to the rotating shaft, the inner metal member (40) including a portion located between the molded resin (30) and the stator, wherein the molded resin (30) is formed by curing a liquid resin injected in a circumferential direction (Z) from the protruding portion so that the liquid resin flows around an entire circumferential direction (Z) which orbits the central axis (C).
  6. The molded motor according to Claim 5, wherein a gate mark (30G) when the liquid resin (30L) is injected to mold the molded resin (30) is present at a portion on a side of the molded resin in the radial direction (Y).
  7. The molded motor according to Claim 5 or 6, wherein a gate mark when the liquid resin is injected to mold the molded resin is present in the protruding portion.
  8. The molded motor according to any one of Claims 5 to 7, further comprising a bracket (61) fixed to the molded resin (30), wherein the bracket (61) includes a first side wall portion (61b) that covers a side surface of the molded resin (30), and at least a part of an outer surface of the molded resin (30) corresponding to the first portion (41) is flush with an outer surface of the first side wall portion (61b) of the bracket or located inside the outer surface of the first side wall portion (61b).
  9. The molded motor according to any one of Claims 5 to 7, further comprising an outer metal member including a lid portion that covers an outer surface of the molded resin (30) located on a side of the central axis direction (X), and a second side wall portion that covers a part of the outer surface of the molded resin (30) located on a side of the radial direction (Y), wherein out of the outer surface of the molded resin (30) located on the side of the radial direction (Y), at least a part of the outer surface that is not covered with the second side wall portion is flush with an outer surface of the second side wall portion of the outer metal member or located inside the outer surface of the second side wall portion.
  10. The molded motor according to any one of Claims 5 to 9, wherein a thickness of the molded resin (30) in a part corresponding to the first portion is 1 mm or more.
  11. The molded motor according to any one of Claims 5 to 10, wherein the molded resin (30) is made of an unsaturated polyester resin.
  12. A mold (100) for manufacturing the molded motor (1) of any of claims 5 to 11 by the method according to any of the claims 1 to 4, comprising a resin injection portion located in a radial direction (Y) of the molded resin (30) after molding in which a molded resin (30) after molding is orthogonal to a central axis direction (X) of a rotating shaft (21) of a molded motor (1), the resin injection portion having a gate (100G), wherein the mold (100) is configured to form: a protruding portion (32) of the molded resin (30), the protruding portion (32) protruding outward in the radial direction (Y) from an outer surface of a main body (31); and a gate mark (30G) of the molded resin (30) at a connection portion between the gate (100G) and the molded resin (30) and at a base part of the protruding portion (32) so that the resin injection portion allows a liquid resin (30L) to be injected in a circumferential direction (Z) through the gate (100G) so as to flow around an entire circumferential direction (Z).

Description

TECHNICAL FIELD The present disclosure relates to a method of manufacturing a molded motor, and a molded motor. BACKGROUND ART Conventionally, a molded motor in which a stator is covered with a molded resin is known (see PTL 1). The molded motor includes, for example, a stator having a stator core and a coil wound around the stator core, a rotor disposed inside the stator, and molded resin that covers the stator. In recent years, with an increase in output of a molded motor, heat generation of a coil in a stator is increasing. Accordingly, there is a problem that the molded resin covering the stator is thermally deteriorated. Therefore, in order to suppress thermal deterioration of the molded resin, it has been proposed to use an epoxy resin containing a filler having high thermal conductivity as the molded resin (see PTL 2). However, in a case where the coil abnormally generates heat due to, for example, an excessive current flowing through the coil of the stator, an insulator that insulates and covers the surface of a conductive wire forming a core wire of the coil melts, which may cause a layer short circuit in which the conductive wires of the coil wound around the stator core are short-circuited. Sparks may be generated when this layer short occurs. At this time, if the coil is disconnected due to abnormal heat generation of the coil, the current does not flow through the coil, and no further trouble occurs. However, in the high-output molded motor, since a wire diameter of the coil of the stator is increased (for example, φ 0.3 mm or more), the coil is less likely to be disconnected even if the coil abnormally generates heat. Therefore, in the high-output molded motor, there is a high possibility that a spark is generated due to a layer short. On the other hand, when the temperature inside the molded motor rises due to heat generation of the coil or the like, a combustible gas may be generated from a resin component such as an insulator interposed between the stator core and the coil. When the combustible gas is present inside the molded motor as described above, if a layer short occurs and a spark is generated, the spark may ignite the gas and ignite. In particular, when the combustible gas is generated in the vicinity of a lead bush, air (oxygen) flows into the vicinity of the lead bush, a spark is likely to occur between lead wires inserted into the lead bush, and the possibility of ignition is increased. At this time, if the lead bush is made of a resin material, the lead bush is melted by ignition. When the lead bush melts as described above, there is a risk that the ignited fire leaks from a portion where the lead bush melts to the outside of the molded motor and spreads. In addition, the fire that has ignited leaks not only from the vicinity of the lead bush but also from other parts of the molded resin. For example, when the molded resin is thermally deteriorated due to heat generation or the like of the coil, and a crack or the like is generated in the molded resin, there is a risk that the ignited fire leaks from a cracked portion of the molded resin to the outside of the molded motor, and as a result, the fire spreads. Therefore, in order to prevent fire spread due to ignition caused by heat generation of a coil wound around a stator, a technique of covering the outside of the stator with a metal member over the entire outer periphery of the stator has been proposed. FIG. 10 is a half cross-sectional view of a molded motor of a comparative example. For example, as illustrated in FIG. 10, in a molded motor including stator 10 having stator core 11 and coil 12, rotor 20 having rotating shaft 21, rotor core 22, and permanent magnet 23, and molded resin 30X, it is conceivable to provide inner metal member 40 as a metallic inner cover inside molded resin 30X. Inner metal member 40 illustrated in FIG. 10 is formed in an annular cylindrical shape having a step portion on an outer surface, and is disposed between molded resin 30X and stator 10. Specifically, annular cylindrical inner metal member 40 covers an outside of stator 10 over the entire circumference, and includes first portion 41 that is a large-diameter portion facing coil end 12a of coil 12 wound around stator core 11, and second portion 42 that is a small-diameter portion facing stator core 11 and having an outer diameter smaller than that of first portion 41. However, when inner metal member 40 is provided so as to cover the outer side of stator 10, "su" is generated in molded resin 30X in a portion located on an outer side in a radial direction of inner metal member 40, and there is a possibility that the strength of molded resin 30X in the portion located on the outer side in the radial direction of inner metal member 40 is reduced. In particular, when inner metal member 40 having first portion 41 having an outer diameter larger than that of second portion 42 is disposed between molded resin 30X and stator 10, a gap between an outer