Rotary electric machine and driving apparatus using the same

Patent metadata

Field	Value
Publication number	US-9444313-B2
Application number	US-201414258499-A
Country	US
Kind code	B2
Filing date	Apr 22, 2014
Priority date	Apr 23, 2013
Publication date	Sep 13, 2016
Grant date	Sep 13, 2016

Abstract

A motor includes a stator core fitted to a cylindrical portion of a case, a rotor core being rotatable in the stator core, soft magnetic poles radially extending from the rotor core, and magnet poles disposed between the soft magnetic poles. The case includes a bottom portion having a ring-shaped plate portion, a protrusion portion, and a bearing-supporting portion extending from the protrusion portion. A condition that L2≧t and a condition that L1≧L2 are met, wherein t represents a thickness of the bottom portion, L1 represents a distance in an axial direction between a side surface of the ring-shaped plate portion close to the stator core and a protrusion end of the protrusion portion close to the rotor core, and L2 represents a distance in the axial direction between the side surface and an end surface of a bearing opposite to the rotor core.

First claim

What is claimed is:

1. A rotary electric machine comprising:
a rotary shaft;
a rotor core fixed to the rotary shaft;
a plurality of soft magnetic poles radially extending from the rotor core;
a plurality of magnet poles disposed between the soft magnetic poles;
a stator disposed radially outward of the soft magnetic poles and the magnetic poles;
a case including
a tubular portion fitted to an outer peripheral surface of the stator,
a ring-shaped plate portion radially inwardly extending from an end of the tubular portion,
a protrusion portion extending from an inner peripheral end of the ring-shaped plate portion toward the rotor core, and

a bearing-supporting portion tube-shaped and extending from an inner peripheral end of the protrusion portion in a direction opposite to the rotor core;
a bearing fitted to an interior of the bearing-supporting portion, the bearing rotatably supporting the rotary shaft; and
a detecting magnet disposed at an end portion of the rotary shaft opposite to the rotor core with respect to the bearing, the detecting magnet generating a magnetism field for detecting a rotary position of the soft magnetic pole and the magnetic pole, wherein
a condition that L2≧t and a condition that L1≧L2 are met, wherein t represents a thickness of the ring-shaped plate portion, L1 represents a distance in an axial direction of the rotary shaft between a side surface of the ring-shaped plate portion close to the stator core and a protrusion end of the protrusion portion close to the rotor core, and L2 represents a distance in the axial direction between the side surface of the ring-shaped plate portion and an end surface of the bearing opposite to the rotor core;
a side surface of the ring-shaped plate portion of the case opposite to the rotor core is interposed between the end surface of the bearing opposite to the rotor core and the rotor core in an axial direction of the rotary shaft;
an end surface of the bearing close to the rotor core is interposed between a side surface of the ring-shaped plate portion of the case close to the rotor core and the rotor core in the axial direction of the rotary shaft, and
a condition that L4=L1+L3+L2 and a condition that L4≧L1+L3 are met, wherein L3 represents a distance of a first gap disposed in the axial direction between the protrusion end of the protrusion portion of the case and the rotor core, and L4 represents a distance between the rotor core and the end surface of the bearing opposite to the rotor core.

2. The rotary electric machine according to claim 1 , wherein
the stator includes
a yoke tubular shaped and fitted to an interior of the tubular portion of the case, and
a plurality of teeth radially inwardly extending from the yoke, and

a condition that t≧(D1×AA)/(2×D0) is met, wherein D0 represents the maximum diameter of the yoke, D1 represents an average diameter of the yoke, and AA represents a thickness of the yoke in a radial direction of the yoke.

3. The rotary electric machine according to claim 1 , wherein
a condition that L3≧3/(δ×t) is met and δ represents a minimum distance of a second gap disposed between the soft magnetic pole, the magnetism pole, and the teeth, in a radial direction of the rotor core.

4. The rotary electric machine according to claim 3 , wherein
the soft magnetic pole has an outer side surface corresponding to a surface disposed radially outward of the soft magnetic pole, the outer side surface is a curved surface extending radially outwardly to have an arc shape, and
a distance of the second gap disposed between the outer side surface and the stator is minimum at a center of the outer side surface in a direction along a periphery of the outer side surface.

5. The rotary electric machine according to claim 1 , wherein
the bearing-supporting portion and the bearing are disposed at a position close to the rotor core with respect of an imagination line, wherein the imagination line corresponds to a line connecting the inner peripheral end of the ring-shaped plate portion to a center of an end surface of the detecting magnet.

6. The rotary electric machine according to claim 1 , wherein
the tubular portion, the ring-shaped plate portion, the protrusion portion, and the bearing-supporting portion, are made of the same material.

7. A driving apparatus comprising:
the rotary electric machine according to claim 1 ; and
a control device mounted to the ring-shaped plate portion, the control device including a control substrate provided with a sensor facing the detecting magnet in the axial direction.

8. The rotary electric machine according to claim 1 , wherein
the ring-shaped plate portion is placed at a position within a thickness of the bearing in the axial direction of the rotary shaft.

9. The rotary electric machine according to claim 1 , wherein
a thickness of the ring-shaped plate portion in the axial direction of the rotary shaft is less than a thickness of the bearing in the axial direction of the rotary shaft.

10. The rotary electric machine according to claim 9 , wherein
the thickness of the ring-shaped plate portion in the axial direction of the rotary shaft overlaps with the thickness of the bearing in the axial direction of the rotary shaft.

11. The rotary electric machine according to claim 1 , wherein
the stator includes a winding wire, and an end surface of the winding wire is arranged at a position between the side surface of the ring-shaped plate portion close to the stator core and a protrusion end of the protrusion portion close to the rotor core.

Assignees

• Denso Corp

Inventors

• Taniguchi Makoto

Classifications

• H02K11/21 Primary

  Devices for sensing speed or position, or actuated thereby (specially adapted for machines having non-mechanical commutating devices H02K29/06, H02K29/14) · CPC title

• H02K2213/03

  Machines characterised by numerical values, ranges, mathematical expressions or similar information · CPC title

• H02K5/04

  Casings or enclosures characterised by the shape, form or construction thereof · CPC title

• H02K5/15

  Mounting arrangements for bearing-shields or end plates · CPC title

• H02K29/08 Primary

  using magnetic effect devices, e.g. Hall-plates, magneto-resistors (H02K29/12 takes precedence) · CPC title