DIRECT CURRENT MOTOR

• US 20160268751A1
• Filed: 12/28/2015
• Published: 09/15/2016
• Est. Priority Date: 03/13/2015
• Status: Active Grant

• Current Assignee: DENSO Corporation
• Original Assignee: DENSO Corporation
• Inventors: HIRABAYASHI, Takashi
• Granted Patent: US 9,985,401 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: H01R 39/38 Brush holders
• CPC Class Codes: H01R 39/381 characterised by the application of pressure to brush
• CPC Class Codes: H01R 39/41 cartridge type
• CPC Class Codes: H02K 23/02 characterised by arrangement for exciting
• CPC Class Codes: H02K 23/08 having series connection of excitation windings
• CPC Class Codes: H02K 5/148 Slidably supported brushes

Abstract

A brush holder has a core side position regulator engaged with a first connection plate to regulate a relative position. The core side position regulator has a projection part projected toward an armature core in the axial direction, and a fitting groove portion defined on both sides of the projection part in a circumferential direction. The relative position in the circumferential direction is regulated by an engagement between the projection part and a slit of the first connection plate. The relative position in the axial direction is regulated by an engagement between sides of the slit and the fitting groove portion. A width of the projection part in the circumferential direction is larger than a width of a brush in the circumferential direction.

Claims

1. A direct current motor having at least four poles comprising:

a commutator having a cylindrical shape on an axis of an armature;

a brush arranged on an outer circumference of the commutator;

a brush holder holding the brush and having insulating properties and;

a pressure component arranged in the brush holder to press the brush to the commutator;

a first connection plate having conductive properties and arranged adjacent to a core of the armature in an axial direction, all of plus side brushes or all of minus side brushes of the brush being electrically connected to the first connection plate through a respective pigtail; and

a second connection plate having conductive properties and arranged opposite from the core of the armature through the first connection plate in the axial direction, all of the minus side brushes or all of the plus side brushes being electrically connected to the second connection plate through a respective pigtail, wherein

the brush holder has an inner circumference opening opposing to the commutator in a radial direction, and an outer circumference wall surface that regulates an outer circumference position of the pressure component in the radial direction,

the first connection plate and the second connection plate are arranged in the axial direction in parallel without electrically contacting, the brush holder being held between the first connection plate and the second connection plate,

the first connection plate has a slit extending from the inner circumference or the outer circumference in the radial direction,

the brush holder has a core side position regulator engaged with the first connection plate to regulate a relative position,

the core side position regulator has

a projection part projected toward the core of the armature in the axial direction, and

a fitting groove portion defined on both sides of the projection part in a circumferential direction,

the relative position in the circumferential direction is regulated by an engagement between the projection part and the slit,

the relative position in the axial direction is regulated by an engagement between at least a part of sides of the slit in the circumferential direction and the fitting groove portion, and

a width of the projection part in the circumferential direction is larger than a width of the brush in the circumferential direction.

2. The direction current motor according to claim 1, wherein

the first connection plate overlaps with an end portion of the brush adjacent to the core of the armature in the axial direction in a state where the brush holder that holds the brush is attached to the first connection plate.

3. The direction current motor according to claim 1, wherein

the commutator includes

a plurality of commutator segments insulated from each other and arranged in a cylindrical state, and

a connector portion that is an end of the respective commutator segments, the connector portion being located adjacent to the core of the armature in the axial direction, an armature coil of the armature being electrically connected to the connector portion, and

the first connection plate has a spreading part which connects the sides of the slit with each other in the circumferential direction at a position on an outer side of an outer circumference of the connector portion in the radial direction.

4. The direction current motor according to claim 3, wherein

the brush holder has a step part located on an outer side of the projection part in the radial direction and located adjacent to the core of the armature in the axial direction,

a level difference is defined between the step part and the projection part, a height of the step part being lower than that of the projection part in the axial direction, and

the spreading part is arranged on a surface of the step part adjacent to the core of the armature in a state where the brush holder is attached to the first connection plate.

5. The direction current motor according to claim 4, wherein

the pressure component has a dimension in the axial direction, and the dimension of the pressure component is smaller than a length of the brush in the axial direction,

the brush holder has

a brush storage chamber that stores the brush, the brush storage chamber being opened to the inner circumference in the radial direction, and

a pressure component storage chamber that stores the pressure component, the brush being located between the commutator and the pressure component storage chamber,

the projection part is formed to correspond to the brush storage chamber on a side adjacent to the core of the armature in the axial direction, and

the step part is formed to correspond to the pressure component storage chamber on a side adjacent to the core of the armature in the axial direction.

6. The direction current motor according to claim 3, wherein

the spreading part extends over the slit in the circumferential direction, and is projected toward the core of the armature in the axial direction with respect to a surface of the first connection plate opposing the core of the armature.

7. The direction current motor according to claim 3, wherein

the spreading part is bent to extend toward the core of the armature in the axial direction with respect to a surface of the first connection plate opposing the core of the armature.

8. The direction current motor according to claim 3, wherein

all of the plus side brushes are electrically connected to the first connection plate which has the spreading part, and

all of the minus side brushes are electrically connected to the second connection plate.

9. The direction current motor according to claim 8, wherein

the second connection plate is directly fixed to a motor case which forms a part of ground circuit, and is electrically connected with the motor case.

10. The direction current motor according claim 1, further comprising:

an armature in which a coil is wave-wound around a core, and

a magnetic field coil connected to the coil of the armature in series or serial-parallel, the magnetic field coil being energized to form magnetic field poles, wherein

the number of the brushes connected to the first connection plate through the pigtail is less than one half of the number of the magnetic field poles, and

the magnetic field coil and the first connection plate are electrically connected.

11. The direction current motor according to claim 1, further comprising:

a plurality of magnetic field coil that are energized to form magnetic field poles, wherein

the magnetic field coils are connected in series or two-parallel, and

the magnetic field coils and the first connection plate are electrically connected with each other.