Electric motor

Patent metadata

Field	Value
Publication number	US-9935525-B2
Application number	US-201314760091-A
Country	US
Kind code	B2
Filing date	Dec 20, 2013
Priority date	Jan 18, 2013
Publication date	Apr 3, 2018
Grant date	Apr 3, 2018

Abstract

An electric motor to be easily assembled while taking the advantages of a retrofitted electric motor, excellent maintenance performance and no fear of damage in a temperature sensitive device due to resin injection pressure. The electric motor includes an electric motor shaft, a rotor, a stator, a housing, a sealing body formed of sealant to cover a coil end of the stator, a temperature sensitive device, an end cover, and a resilient retaining member. The electric motor shaft passes through the end cover. The sealing body includes a temperature-sensitive-device support surface opposed to the end cover. The temperature sensitive device is retained between the end cover and the temperature-sensitive-device support surface while the retaining member is interposed between the temperature sensitive device and the end cover.

First claim

The invention claimed is:

1. An electric motor comprising:
an electric motor shaft;
a rotor which rotates about the electric motor shaft;
a stator disposed in an outer periphery of the rotor and having a coil end including an inner side surface facing inward in a motor radial direction perpendicular to a motor axial direction which is an axial direction of the electric motor shaft;
a housing which houses the rotor and the electric motor shaft;
a sealing body formed in the housing, the sealing body being formed of sealant made of synthetic resin material having a heat conductive property and electrical insulation property, the sealant having been injected so as to cover at least a coil end of the stator;
a temperature sensitive device disposed in the housing and configured to be operated in response to temperature, the temperature sensitive device being a temperature measuring device;
an end cover to be mounted on an axial end of the housing by an axial fastening force applied to the end cover in the motor axial direction, the end cover including an inner surface facing inward in the motor axial direction; and
a retaining member having elasticity which allows the retaining member to be interposed between the temperature sensitive device and the inner surface of the end cover in the motor axial direction, wherein:
the electric motor shaft is disposed to pass through the end cover;
the sealing body has surfaces including a radially inner portion which covers the inner side surface of the coil end, the radially inner portion being formed with a recess portion opened outward in the motor axial direction and inward in the motor radial direction to include a temperature-sensitive-device contact surface facing inward in the motor radial direction and a temperature-sensitive-device support surface opposed to the inner surface of the end cover in the motor axial direction;
the temperature sensitive device is placed on the temperature-sensitive-device support surface in close contact with the temperature-sensitive-device contact surface in the motor radial direction; and
the end cover is mounted to the axial end of the housing by the axial fastening force applied to the end cover so as to elastically retain the temperature sensitive device between the inner surface of the end cover and the temperature-sensitive-device support surface by the axial fastening force applied to the end cover and the elasticity of the retaining member interposed between the temperature sensitive device and the inner surface of the end cover.

2. The electric motor according to claim 1 , wherein the end cover has a center portion formed with a projection portion projecting axially inward of the end cover in the motor axial direction beyond the inner surface of the end cover, the projection portion having an outer circumferential surface opposed to the temperature-measuring-device contact surface of the recess portion in the motor radial direction with a gap, so as to retain the retaining member between the temperature sensitive device and the outer circumferential surface of the projection portion so that the retaining member bridges the gap.

3. The electric motor according to claim 1 , wherein the retaining member is formed of a material having a property of making heat conduction between the temperature sensitive device and the end cover be smaller than heat conduction between the sealing body and the temperature sensitive device.

4. The electric motor according to claim 1 , wherein the retaining member and the temperature sensitive device are adhered to each other to be integral with each other.

5. The electric motor according to claim 1 , wherein a conductive wire is connected to the temperature sensitive device, and a space portion devoid of the sealing body is formed between the coil end and the housing, the conductive wire being disposed in the space portion.

Assignees

• Kobelco Constr Mach Co Ltd

Inventors

• Koiwai Kazushige
• Saiki Seiji

Classifications

• H02K11/25 Primary

  Devices for sensing temperature, or actuated thereby · CPC title

• H02K5/08

  Insulating casings · CPC title

• G01K1/14

  Supports; Fastening devices; Arrangements for mounting thermometers in particular locations · CPC title

• G01K13/08

  in rotary movement · CPC title

• H02K11/0047 Primary

  Electricity · mapped topic