Electric motor device

Patent metadata

Field	Value
Publication number	US-10944309-B2
Application number	US-201916279187-A
Country	US
Kind code	B2
Filing date	Feb 19, 2019
Priority date	Aug 19, 2016
Publication date	Mar 9, 2021
Grant date	Mar 9, 2021

Abstract

When a rotor performs an ordinary rotation operation, an axial position of the rotor is retained such that the rotor is rotatable with respect to a stator. When a parking brake switch is operated while a vehicle is at stoppage, a rotor slider slides the rotor in an axial direction against a preload of an axially preloading part. This brings an engaging portion of the rotor into engagement with an engaged portion of a housing. The reverse input holder retains the rotation angle of the rotor during the engagement due to the fact that the engagement between the engaging portion and the engaged portion is maintained against a reverse input load acting on the rotor as an external force that accompanies a reaction force of a pressing force of a brake friction member.

First claim

What is claimed is:

1. An electric motor device comprising:
a housing;
a stator fixed to the housing; and
a rotor supported by the housing and configured to rotate with respect to the stator, wherein
the rotor is configured to be slidable in an axial direction of a rotation axis,
the electric motor device further comprises a rotor slider configured to slide the rotor in the axial direction and a reverse input holder configured to prevent rotation of the rotor in at least one direction,
the reverse input holder includes an engaging portion provided on the rotor and an engaged portion provided on the housing and configured to be engaged by the engaging portion in a state that the rotor is caused to slide in one axial direction by the rotor slider,
when the engaging portion and the engaged portion are in engagement, the engagement between the engaging portion and the engaged portion is maintained against a reverse input load that acts on the rotor as an external force, and thereby retains a rotation angle of the rotor,
the rotor and the stator are arranged such that orientations of magnetic poles are in parallel with the rotational axis,
the rotor slider is configured to slide the rotor in the axial direction by an electromagnetic force in the axial direction that acts on the stator and the rotor,
the rotor is a magnetic field mechanism having a permanent magnet,
the stator is an excitation mechanism having coils that form a magnetic circuit corresponding to three-phase alternating current, and
the rotor slider is configured to generate the electromagnetic force by a current component corresponding to an excitation magnetic flux in a direction corresponding to an orientation of magnetic poles of the magnetic field mechanism.

2. The electric motor device as claimed in claim 1 , further comprising an axially preloading part to apply preload on the rotor against the housing so as to hold the axial position of the rotor, wherein the rotor slider is configured to slide the rotor in the axial direction against the preload of the axially preloading part.

3. The electric motor device as claimed in claim 1 , wherein the rotor has a magnetic body on an axial end face thereof, and the rotor slider is an electromagnet arranged so as to face the magnetic body.

4. The electric motor device as claimed in claim 1 , wherein the engaging portion is provided on an axial end face of the rotor, the engaged portion is provided on a surface of the housing opposite to the axial end face of the rotor, and the engaging portion and the engaged portion have contact surfaces that can contact with each other in a circumferential direction.

5. The electric motor device as claimed in claim 1 , wherein the engaging portion is provided on an outer circumferential surface of the rotor, the engaged portion is provided on an inner circumferential surface of the housing opposite to the outer circumferential surface of the rotor, and the engaging portion and the engaged portion have contact surfaces that can contact with each other in a circumferential direction.

Assignees

• Ntn Toyo Bearing Co Ltd

Inventors

• Masuda Yui

Classifications

• H02K7/12 Primary

  with auxiliary limited movement of stators, rotors or core parts, e.g. rotors axially movable for the purpose of clutching or braking · CPC title

• H02K1/2798 Primary

  where both axial sides of the stator face a rotor · CPC title

• F16D65/18

  adapted for drawing members together {, e.g. for disc brakes} · CPC title

• H02K7/06

  Means for converting reciprocating motion into rotary motion or vice versa · CPC title

• H02K16/04

  Machines with one rotor and two stators · CPC title