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EP-4738653-A1 - MOTOR AND ROBOT INCLUDING MOTOR

EP4738653A1EP 4738653 A1EP4738653 A1EP 4738653A1EP-4738653-A1

Abstract

An object of the present invention is to provide a motor (100) advantageous for cost reduction while suppressing performance degradation. A motor (100) includes a stator (2) including an iron core (21) having a plurality of teeth (22) and a plurality of slots (24) extending in a radial direction, and a winding wire (25) wound around each of the slots (24), and a rotor (3) including a magnet (32) including magnetic poles (33) facing the plurality of teeth (22) in the radial direction. The iron core (21) is integrally formed in a circumferential direction, and the magnet (32) is formed of a material having a residual magnetic flux density of 1.4 T or more, and an iron core utilization rate of the iron core (21) is less than 60%.

Inventors

  • MORITANI, KOJI

Assignees

  • Sumitomo Heavy Industries, LTD.

Dates

Publication Date
20260506
Application Date
20251015

Claims (7)

  1. A motor (100) comprising: a stator (2) including an iron core (21) having a plurality of teeth (22) and a plurality of slots (24) extending in a radial direction, and a winding wire (25) wound around each of the slots (24); and a rotor (3) including a magnet (32) having magnetic poles (33) facing the plurality of teeth (22) in the radial direction, wherein the iron core (21) is integrally formed in a circumferential direction, the magnet (32) is formed of a material having a residual magnetic flux density of 1.4 T or more, and an iron core (21) utilization rate of the iron core (21) is less than 60%.
  2. The motor (100) according to claim 1, wherein a packing factor of the winding wire (25) in the slot (24) is 30% or less.
  3. The motor (100) according to claim 2, wherein a radial gap (41) between the magnet (32) and the teeth (22) is less than 1% of an outer diameter of the stator (2).
  4. The motor (100) according to claim 3, wherein a maximum value of a surface magnetic flux density of each of the magnetic poles (33) in a state where the magnet (32) faces the teeth (22) is 1.1 T or more.
  5. The motor (100) according to claim 4, wherein the motor (100) has an inner rotor structure in which the rotor (3) is surrounded by the stator (2), and has a frameless structure in which an outer peripheral surface of the iron core (21) is an outer peripheral surface of the motor (100).
  6. The motor (100) according to claim 5, wherein the number of the teeth (22) is 12, the number of the magnetic poles (33) is 14, and the magnet (32) has a segment structure split for each magnetic pole.
  7. A robot (200) comprising: the motor (100) according to claim 1.

Description

BACKGROUND OF THE INVENTION Field of the Invention The present invention relates to a motor and a robot including the motor. Description of Related Art A motor including a rotor and a stator is known. For example, International Publication No. 2022/019074 describes an electric motor including a rotor having a permanent magnet and a stator having teeth disposed to face the rotor. The rotor of the electric motor includes an iron core and a permanent magnet disposed in an insertion hole of the iron core, and a residual magnetic flux density of the permanent magnet is 1.3 T or more. SUMMARY OF THE INVENTION The inventor has obtained the following recognition. There is a need for a motor that is small-sized, satisfies desired performance, and can be cost-reduced. To improve the torque performance, it is conceivable to perform high-density winding by manual winding. However, this method is high in cost because the method cannot be automated. In addition, to realize the high-density winding, it is conceivable to adopt a split core in which an iron core is split into a plurality of pieces for each tooth. However, in this method, post-processes such as connection work after winding are increased, and dedicated equipment is used. Therefore, this method results in high costs. In addition, in a multi-pole multi-slot specification, a core back, which is a connecting portion of the split core, is narrowed. As a result, assembling performance degrades. In addition, to accurately assemble the iron core, a cutting process of the core after connection is added, which results in high costs. In a motor configuration of the related art, there is a problem in that when the density of a winding wire is reduced to reduce costs, the performance degrades. From these, in the motor of the related art, it is insufficient from the viewpoint of providing a motor advantageous for cost reduction while suppressing performance degradation. The present invention has been made in view of such a problem, and an object of the present invention is to provide a motor advantageous for cost reduction while suppressing performance degradation. To solve the above problem, a motor according to an aspect of the present invention includes: a stator including an iron core having a plurality of teeth and a plurality of slots extending in a radial direction, and a winding wire wound around each of the slots; and a rotor including a magnet having magnetic poles facing the plurality of teeth in the radial direction. The iron core is integrally formed in a circumferential direction, the magnet is formed of a material having a residual magnetic flux density of 1.4 T or more, and an iron core utilization rate of the iron core is less than 60%. According to another aspect of the invention, there is provided a robot. The robot includes the motor. Note that, any combination of the above components, and those obtained by substituting the components or expressions in the present invention with each other between methods, systems, or the like are also effective as aspects of the present invention. According to the present invention, it is possible to provide the motor advantageous for cost reduction while suppressing performance degradation. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a cross-sectional view obtained by cutting a motor of a first embodiment taken along a plane perpendicular to an axial direction.FIG. 2 is a side view showing a robot according to a second embodiment. DETAILED DESCRIPTION OF THE INVENTION Hereinafter, the present invention will be described with reference to each drawing based on preferred embodiments. In the embodiments and modification examples, the same or equivalent components and members will be represented by the same reference numerals and duplicate descriptions will be appropriately omitted. In addition, the dimensions of members in each drawing have been appropriately enlarged and reduced for easy understanding. In addition, in each drawing, some of the members not important for the description of the embodiments are not shown. In addition, when the same or equivalent components are described to be distinguished from each other, the description will be made with capital letters such as A, B, and C added to the ends of the reference numerals. In addition, although terms including ordinal numbers such as "first" and "second" will be used to describe various components, the terms will be used only for the purpose of distinguishing one component from the other component and no component is limited by the terms. [First Embodiment] A motor 100 according to a first embodiment of the present invention will be described with reference to FIG. 1. FIG. 1 is a cross-sectional view of the motor 100. This figure is a cross-sectional view cut taken along a plane perpendicular to a rotation axis La of a rotor 3 of the motor 100. Hereinafter, a direction parallel to the rotation axis La is referred to as an "axial direction", and a circumferenti