Motor with speed reduction mechanism

Patent metadata

Field	Value
Publication number	US-9979261-B2
Application number	US-201514638502-A
Country	US
Kind code	B2
Filing date	Mar 4, 2015
Priority date	Jul 30, 2009
Publication date	May 22, 2018
Grant date	May 22, 2018

Abstract

In a brush holder accommodating part 26 d of a gear housing 26 , paired flat surface parts 26 c and paired curved parts 26 b are alternately disposed so as to be formed into an elliptical shape, one of the paired flat surface parts is formed with first heat sinks 26 i , and two brushes 20 and 20 mounted on a brush holder unit 19 accommodated in the brush holder accommodating part 26 d are disposed near the first heat sinks 26 i.

First claim

What is claimed is:

1. A motor with speed reduction mechanism, comprising:
a cylindrical yoke;
a magnet formed with four poles, two different magnetic poles being alternately disposed on an inner peripheral surface of the yoke;
an armature including: an armature shaft; a commutator which is fixed to the armature shaft; and a core which is fixed to the armature shaft and around which a winding wire is wound, wherein the armature is rotatably disposed on an inner side of the magnet;
first and second brushes slidably contacting with the commutator;
a brush holder unit in which the first and second brushes are arranged;
a gear housing formed into a bottomed open shape and formed with a speed reduction mechanism accommodating part having accommodated therein a speed reduction mechanism engaged with a worm formed on the armature shaft; and
a gear housing cover covering an opening of the gear housing, a control board being mounted on the same side as the opening of the gear housing;
wherein the first and second brushes are inclined with respect to each other at an angle of substantially 90 degrees in a circumferential direction of the armature shaft; and
wherein the brush holder unit is accommodated in the gear housing so that the first and second brushes are disposed on the opposite side of the gear housing from the opening of the gear housing, and away from the control board.

2. The motor with speed reduction mechanism according to claim 1 , wherein the first and second brushes inclined with respect to each other at an angle of substantially 90 degrees is disposed on the axially opposite side from one end of the output shaft, which protrudes from the gear housing.

3. The motor with speed reduction mechanism according to claim 1 , wherein the first and second brushes inclined with respect to each other at an angle of substantially 90 degrees is disposed at a position in an axial direction of the output shaft, away from at least one of a plurality of field effect transistors (FETs) mounted on the control board.

4. The motor with speed reduction mechanism according to claim 1 , wherein
a first heat dissipating member is formed at a back surface of the speed reduction mechanism accommodating part of the gear housing,
the first and second brushes are disposed in the vicinity of the first heat dissipating member so that heat generated from the first and second brushes is transmitted to the first heat dissipating member,
brush holder abutting parts respectively abutting on the brush holder unit are formed in a brush holder accommodating part of the gear housing, and
heat generated from the first and second brushes is transmitted to the brush holder abutting parts, and dissipated from the first heat dissipating member to the outside of the gear housing.

5. The motor with speed reduction mechanism according to claim 4 , wherein a heat conducting member is disposed between the first heat dissipating member and the first and second brushes.

6. A motor with speed reduction mechanism, comprising:
a cylindrical yoke;
a magnet having four poles, two different magnetic poles being alternatively disposed on an inner peripheral surface of the yoke;
an armature provided with:
an armature shaft;
a commutator fixed to the armature shaft and formed of a plurality of segments;
an armature core fixed to the armature shaft and around which a winding wire is wound, at least one part of the armature core being disposed on the inner side of the magnet; and
a plurality of connecting members with which paired segments facing each other among the plurality of segment are electrically connected to each other;

a brush holder unit including first and second brushes slidably contacting with the commutator and disposed so as to be shifted by approximately 90 degrees from each other with respect to a center of rotation of the armature shaft and brush holders holding the first and second brushes;
a gear housing including a speed reduction mechanism accommodating part having accommodated therein a speed reduction mechanism engaged with a worm formed on the armature shaft;
a control board for controlling rotation of the armature; and
a gear housing cover covering an opening of the gear housing;
wherein the first and second brushes are inclined with respect to each other at an angle of substantially 90 degrees in a circumferential direction of the armature shaft; and
wherein the brush holder unit is accommodated in the gear housing so that the first and second brushes are disposed on the opposite side of the gear housing from the opening of the gear housing, and away from the control board.

7. The motor with speed reduction mechanism according to claim 6 , wherein the first and second brushes inclined with respect to each other at an angle of substantially 90 degrees is disposed on the axially opposite side from one end of the output shaft, which protrudes from the gear housing.

8. The motor with speed reduction mechanism according to claim 6 , wherein the first and second brushes inclined with respect to each other at an angle of substantially 90 degrees is disposed at a position in an axial direction of the output shaft, away from at least one of a plurality of field effect transistors (FETs) mounted on the control board.

9. The motor with speed reduction mechanism according to claim 6 , wherein
a first heat dissipating member is formed on the gear housing in the vicinity of the first and second brushes,
brush holder abutting parts respectively abutting on the brush holder unit are formed in a brush holder accommodating part of the gear housing, and
heat generated from the first and second brushes is transmitted to the brush holder abutting parts, and dissipated from the first heat dissipating member to the outside of the gear housing.

10. The motor with speed reduction mechanism according to claim 9 , wherein a heat conducting member is disposed between the first heat dissipating member and the first and second brushes.

11. A motor with speed reduction mechanism, comprising:
a cylindrical yoke;
a magnet having at least four poles, two different magnetic poles being alternatively disposed on an inner peripheral surface of the yoke;
an armature provided with:
an armature shaft;
a commutator fixed to the armature shaft and formed of a plurality of segments; and
an armature core fixed to the armature shaft and around which a winding wire is wound, at least one part of the armature core being disposed on the inner side of the magnet;

at least two brushes slidably contacting with the commutator;
a brush holder unit including the brushes;
a bottomed gear housing with an opening, the gear housing including a speed reduction mechanism accommodating part having accommodated therein a speed reduction mechanism engaged with a worm formed on the armature shaft;
a control board for controlling rotation of the armature; and
a gear housing cover covering the opening of the gear housing,
a brush terminal connecting part which is provided to the brush holder unit, and electrically connected to the brush holder unit and the control board through two electrical conducting members,
wherein two brushes are inclined with respect to each other at an angle of substantially 90 degrees, and at least one of said two brushes are disposed at a position away from the control board.

12. The motor with speed reduction mechanism according to claim 11 , wherein at least one of said two brushes inclined with respect to each other at an angle of substantially 90 degrees is disposed at a position away from the control board in a direction of an angle of substantially 90 or more degrees with respect t

Assignees

• Mitsuba Corp

Inventors

• Tanaka Hiroto
• Kanai Takeshi
• Kimura Masaaki
• Tsuchiya Koji

Classifications

• H02K9/28 Primary

  Cooling of commutators, slip-rings or brushes e.g. by ventilating · CPC title

• H02K13/006

  Structural associations of commutators · CPC title

• H02K5/148

  Slidably supported brushes · CPC title

• H02K7/1166

  comprising worm and worm-wheel (structural association with bearings specially adapted for worm gear drives H02K7/081) · CPC title

• H02K5/18

  with ribs or fins for improving heat transfer · CPC title