Electromagnetic clutch

Patent metadata

Field	Value
Publication number	US-9982725-B2
Application number	US-201515518810-A
Country	US
Kind code	B2
Filing date	Dec 8, 2015
Priority date	Dec 25, 2014
Publication date	May 29, 2018
Grant date	May 29, 2018

Abstract

An inner peripheral surface of an outer cylindrical tubular portion and an outer peripheral surface of an inner cylindrical tubular portion of a rotor are respectively shaped into a stepped form. A radial distance between the outer cylindrical tubular portion and the inner cylindrical tubular portion at a counter-armature side location is larger than that of an armature side location in the rotor. An outer peripheral surface of an outer cylindrical tubular portion and an inner peripheral surface of an inner cylindrical tubular portion of a stator are respectively shaped into a stepped form. A radial distance between the outer peripheral surface of the outer cylindrical tubular portion and the inner peripheral surface of the inner cylindrical tubular portion at the counter-armature side location is larger than that of the armature side location in the stator.

First claim

The invention claimed is:

1. An electromagnetic clutch comprising:
an electromagnetic coil that generates an electromagnetic attractive force at a time of energizing the electromagnetic coil;
a rotor that is rotated about a rotational central axis when the rotor receives a rotational drive force from a drive source;
an armature that is coupled to the rotor by the electromagnetic attractive force at the time of energizing the electromagnetic coil and is decoupled from the rotor at a time of deenergizing the electromagnetic coil; and
a stator that is placed in an inside of the rotor and receives the electromagnetic coil in an inside of the stator, wherein:
the rotor includes:
an outer cylindrical tubular portion that is centered at the rotational central axis;
an inner cylindrical tubular portion that is placed in an inside of the outer cylindrical tubular portion and is centered at the rotational central axis; and
a wall portion that connects between an end part of the outer cylindrical tubular portion and an end part of the inner cylindrical tubular portion, which are located on an armature side where the armature is placed;

the stator includes:
an outer cylindrical tubular portion that is centered at the rotational central axis;
an inner cylindrical tubular portion that is placed in an inside of the outer cylindrical tubular portion of the stator and is centered at the rotational central axis; and
a wall portion that connects between an end part of the outer cylindrical tubular portion of the stator and an end part of the inner cylindrical tubular portion of the stator, which are located on a counter-armature side that is apart from the armature;

the outer cylindrical tubular portion and the inner cylindrical tubular portion of the stator are placed in an inside space, which is surrounded by the outer cylindrical tubular portion, the inner cylindrical tubular portion and the wall portion of the rotor; and an outer peripheral surface of the outer cylindrical tubular portion of the stator is opposed to an inner peripheral surface of the outer cylindrical tubular portion of the rotor such that a gap is formed between the outer peripheral surface of the outer cylindrical tubular portion of the stator and the inner peripheral surface of the outer cylindrical tubular portion of the rotor; and an inner peripheral surface of the inner cylindrical tubular portion of the stator is opposed to an outer peripheral surface of the inner cylindrical tubular portion of the rotor such that a gap is formed between the inner peripheral surface of the inner cylindrical tubular portion of the stator and the outer peripheral surface of the inner cylindrical tubular portion of the rotor;
the electromagnetic coil is placed in an inside space that is surrounded by the outer cylindrical tubular portion, the inner cylindrical tubular portion and the wall portion of the stator;
the inner peripheral surface of the outer cylindrical tubular portion of the rotor is shaped into a stepped form that includes:
a first inner peripheral surface;
a second inner peripheral surface that is located on the counter-armature side of the first inner peripheral surface and has a diameter, which is larger than a diameter of the first inner peripheral surface; and
a step that is tapered;

the outer peripheral surface of the inner cylindrical tubular portion of the rotor is shaped into a stepped form that includes:
a first outer peripheral surface;
a second outer peripheral surface that is located on the counter-armature side of the first outer peripheral surface and has a diameter, which is smaller than a diameter of the first outer peripheral surface; and
a step that is tapered;

with respect to a distance between the outer cylindrical tubular portion and the inner cylindrical tubular portion of the rotor measured in a radial direction of the rotor, the outer cylindrical tubular portion and the inner cylindrical tubular portion of the rotor satisfy a relationship of that a second distance between the outer cylindrical tubular portion and the inner cylindrical tubular portion measured in the radial direction of the rotor at a location on the counter-armature side of a center location centered in an axial direction of the rotational central axis is larger than a first distance between the outer cylindrical tubular portion and the inner cylindrical tubular portion measured in the radial direction of the rotor at a location on the armature side of the center location centered in the axial direction of the rotational central axis;
the outer peripheral surface of the outer cylindrical tubular portion of the stator is shaped into a stepped form that includes:
a first outer peripheral surface;
a second outer peripheral surface that is located on the counter-armature side of the first outer peripheral surface and has a diameter, which is larger than a diameter of the first outer peripheral surface; and
a step that is tapered;

the inner peripheral surface of the inner cylindrical tubular portion of the stator is shaped into a stepped form that includes:
a first inner peripheral surface;
a second inner peripheral surface that is located on the counter-armature side of the first inner peripheral surface and has a diameter, which is smaller than a diameter of the first inner peripheral surface; and
a step that is tapered;

with respect to a distance between an outer peripheral surface of the outer cylindrical tubular portion of the stator and an inner peripheral surface of the inner cylindrical tubular portion of the stator measured in a radial direction of the stator, the outer cylindrical tubular portion and the inner cylindrical tubular portion of the stator satisfy a relationship of that a second distance between the outer peripheral surface of the outer cylindrical tubular portion of the stator and the inner peripheral surface of the inner cylindrical tubular portion of the stator measured in the radial direction of the stator at the location on the counter-armature side of the center location centered in the axial direction of the rotational central axis is larger than a first distance between the outer peripheral surface of the outer cylindrical tubular portion of the stator and the inner peripheral surface of the inner cylindrical tubular portion of the stator measured in the radial direction of the stator at the location on the armature side of the center location centered in the axial direction of the rotational central axis; and
with respect to a thickness of the outer cylindrical tubular portion of the stator measured in the radial direction of the stator and a thickness of the inner cylindrical tubular portion of the stator measured in the radial direction of the stator, at least one of the outer cylindrical tubular portion and the inner cylindrical tubular portion of the stator satisfies a relationship of that a second thickness of the at least one of the outer cylindrical tubular portion and the inner cylindrical tubular portion of the stator measured in the radial direction of the stator at the location on the counter-armature side of the center location centered in the axial direction of the rotational central axis is larger than a first thickness of the at least one of the outer cylindrical tubular portion and the inner cylindrical tubular portion of the stator measured in the radial direction of the stator at the location on the armature side of the center location centered in the axial direction of the rotational central axis.

2. The electromagnetic clutch according to claim 1 , wherein the step of the outer cylindrical tubular portion of the rotor, the step of the inner cylindrical tubular portion of the rotor, the step of the outer cylindrical tubular portion of the stator, and the step of the inner cylindrical tubular portion of the stator are respectively located between an armatu

Assignees

• Denso Corp

Inventors

• Fukumura Yoshinori

Classifications

• F16D27/08

  with friction surfaces arranged externally to the flux · CPC title

• F16D28/00

  Electrically-actuated clutches (arrangements for synchronisation F16D23/02; clutches actuated directly by means of an electromagnet F16D27/00; automatic clutches F16D43/00 - F16D45/00; external control F16D48/00) · CPC title

• F16D27/112 Primary

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

• F16D27/02

  with electromagnets incorporated in the clutch, i.e. with collecting rings {(F16D27/004 takes precedence)} · CPC title

• F16D27/14 Primary

  Details · CPC title