Power transmission device

Patent metadata

Field	Value
Publication number	US-11353068-B2
Application number	US-201916545528-A
Country	US
Kind code	B2
Filing date	Aug 20, 2019
Priority date	Jun 23, 2017
Publication date	Jun 7, 2022
Grant date	Jun 7, 2022

Abstract

A power transmission device includes an electromagnet, a rotor, an armature and a hub. The hub couples the armature to a shaft of a drive-subject device. The hub includes: an outer hub that is coupled to the armature; a boss portion that is coupled to the shaft; an inner side plate-shaped portion that extends from the boss portion toward a radially outer side; and an inner plate that is placed between the outer hub and the inner side plate-shaped portion. The inner side plate-shaped portion and the inner plate are formed integrally in one piece. At least one of the inner side plate-shaped portion and the inner plate is formed by a member that is configured to deform or melt with heat generated by friction between the rotor and the armature when the shaft of the drive-subject device is locked at a time of energizing the electromagnet.

First claim

What is claimed is:

1. A power transmission device configured to transmit a rotational drive force, which is outputted from a drive source, to a drive-subject device, comprising:
an electromagnet that is configured to generate a magnetic attractive force when the electromagnet is energized;
a rotor that is configured to rotate about a predetermined rotational axis when the rotor receives the rotational drive force, which is outputted from the drive source, through a belt;
an armature that is configured to be coupled to and is rotated together with the rotor when the electromagnet is energized, wherein the armature is configured to be decoupled from the rotor when the electromagnet is deenergized; and
a hub that couples the armature to a shaft of the drive-subject device, wherein:
the hub includes:
an outer hub that is coupled to the armature;
a boss portion that is coupled to the shaft;
an inner side plate-shaped portion that extends from the boss portion toward a radially outer side in a radial direction of the shaft; and
an inner plate that is placed between the outer hub and the inner side plate-shaped portion;

the inner side plate-shaped portion and the inner plate are secured together; and
at least one of the inner side plate-shaped portion and the inner plate is formed by a member that is configured to deform or melt with heat generated by friction between the rotor and the armature when the shaft of the drive-subject device is locked at a time of energizing the electromagnet;
the inner side plate-shaped portion is placed such that a center of the inner side plate-shaped portion coincides with the rotational axis of the rotor;
the armature includes a plurality of annular portions that are concentrically arranged about the rotational axis of the rotor;
at least a radially innermost one of the plurality of annular portions has a circular opening at a center of the radially innermost one of the plurality of annular portions and is located between the rotor and the inner side plate-shaped portion;
a largest outer diameter of the inner side plate-shaped portion, which is largest in a circumferential direction of the inner side plate-shaped portion, is larger than an inner diameter of the circular opening of the radially innermost one of the plurality of annular portions; and
two opposite axial sides of a radially outer end part of the inner side plate-shaped portion, which is located on a radially outer side of an inner peripheral surface of the circular opening, are both covered by the inner plate.

2. The power transmission device according to claim 1 , wherein the inner side plate-shaped portion includes a projection that outwardly projects in the radial direction of the shaft.

3. The power transmission device according to claim 1 , wherein:
the outer hub is fixed to at least a radially outermost one of the plurality of annular portions such that the outer hub covers an outer peripheral part of the inner side plate-shaped portion; and
a smallest inner diameter of an inner peripheral surface of the outer hub is larger than the largest outer diameter of the inner side plate-shaped portion, which is largest in the circumferential direction of the inner side plate-shaped portion.

4. The power transmission device according to claim 1 , wherein the inner side plate-shaped portion is shaped in a circular disk form and has protrusions and recesses at an outer peripheral surface of the inner side plate-shaped portion.

5. The power transmission device according to claim 1 , wherein:
a recess is formed at the inner plate;
the armature has a projection that projects toward the inner plate in an axial direction of the shaft; and
the projection is inserted into the recess formed at the inner plate.

6. The power transmission device according to claim 1 , wherein a cross section of an inner peripheral surface of the radially innermost one of the plurality of annular portions is shaped in a stepped form.

7. The power transmission device according to claim 1 , wherein the inner side plate-shaped portion has a projection that projects in an axial direction of the shaft and is located on a radially inner side of the radially innermost one of the plurality of annular portions.

8. The power transmission device according to claim 1 , wherein at least one of the inner side plate-shaped portion and the inner plate is made of resin.

9. The power transmission device according to claim 1 , wherein the inner plate is made of resin, and the inner side plate-shaped portion is made of metal.

10. The power transmission device according to claim 1 , wherein the inner plate is made of resin, and the outer hub is made of metal.

Assignees

• Denso Corp

Inventors

• Konishi Toshihiro
• Sakuraba Shigeyoshi
• Hirose Takayuki
• Hayashi Toshihiro

Classifications

• F16D27/112 Primary

  with flat friction surfaces, e.g. discs · CPC title

• F16D27/14

  Details · CPC title

• F16D9/02 Primary

  by thermal means, e.g. melting member · CPC title