JP2758795B2 - Flat DC motor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a DC motor having a brush as a brush, and more particularly to a DC motor having a commutator formed in a conical shape.

[0002]

2. Description of the Related Art In a conventional motor, a rotor wound with a winding is supported by a shaft rotatably supported by a bearing provided in a motor case. The rotor is provided with a cylindrical or disc-shaped commutator to which a brush connected to a power supply is pressed to switch the direction and phase of a current supplied from the brush and flowing through the winding. A groove is formed on the surface of the commutator by a cutter or the like in accordance with the number of poles, and the commutator is divided.

[0003]

A motor using a commutator having a cylindrical shape has a good reputation in terms of noise and motor reliability. However, since the commutator is cylindrical, the motor has an axial direction. Space increases. Further, the brush used in this type of motor has a narrower interval than the width (diameter) direction of the commutator in order to press against the commutator. For this reason, the motor is assembled by inserting the commutator between the brushes having a small interval, and there is a problem in the assemblability.

On the other hand, in a motor using a disk-shaped commutator, there is no problem in the bulkiness in the axial direction or the assembling property, but it is larger in the radial direction than in a cylindrical commutator. The problem remains.

That is, assuming that the commutator has three poles, grooves are formed on the surface of the commutator at intervals of 120 ° using a cutter. At this time, if the commutator is cylindrical, the groove can be formed by moving the cutter or the commutator in the axial direction, so that the commutator can be divided without interfering with other grooves. However, when a groove is formed in a disc-shaped commutator, the blade of the cutter has a circular shape, so a clearance for the blade must be formed at the center of the commutator, and there is a limit in reducing the diameter. In other words, the only way to make the contact surface of the brush the same as the cylindrical commutator is to increase it in the radial direction. As a result, the peripheral speed of the commutator increases,
Noise is likely to appear.

[0006]

According to the present invention, there is provided a DC motor having a commutator unit that rotates integrally with a rotor, wherein a commutator unit having a conical commutator segment is provided. A case that is open on the side and supports the commutator unit via a support shaft on the other side, a lid that closes the opening of the case from the axial direction of the support shaft, and is provided so as to be able to contact the commutator segment. A brush, wherein the brush has a plate shape extending and formed in a direction intersecting the axial direction of the support shaft, and a free end of the commutator segment when the opening is closed by the lid. 3. The bearing according to claim 2, wherein a base end side of the case is supported by the lid so as to be pressed against the conical surface, and the support shaft is provided at a portion of the case facing the commutator unit. Just rotate itself And supports to.

[0007]

According to the first aspect of the present invention, a commutator unit provided with a commutator segment formed in a conical shape is supported via a support shaft on the other side of the case having one side opened, and the other side of the case is provided. A lid closing the opening has a base end side of a plate-shaped brush formed so as to extend in a direction intersecting with the axial direction of the support shaft. When the opening is closed by the lid, its free end is the commutator. Since it is provided so as to be pressed along the conical surface of the segment, the bulk of the commutator segment in the axial and radial directions is cylindrical and disc-shaped while securing the contact surface between the brush and the commutator segment. Of the commutator segments. Further, the pressure contact between the brush and the commutator segments is completed only by attaching the lid to the case. Claim 2
In the invention described in the above, the support shaft is rotatably supported only by a bearing portion provided at a portion of the case facing the commutator unit. You don't have to.

[0008]

Embodiments of the present invention will be described below with reference to the drawings. In FIG. 1, reference numeral 1 denotes a flat DC motor (hereinafter, referred to as a flat DC motor).
Simply referred to as "motor"). Case 2 of this motor 1
Is open on one side. Inside the case 2
Main part of the rotor 3 and the stator 4 is rotor case 2
The opening is closed by a lid 5 and is incorporated. Opposite the opening
A bearing portion 6 is formed on the bottom portion 2a of the case 2 which projects upward (opening side) , and a support shaft 11 is provided with a free end 11a in a shaft hole 6a formed in the bearing portion 6. It is rotatably supported by protruding from the case 2 to the outside of the case 2.

[0009] The rotor 3 includes a core 7, commutator holder 8, be composed of the commutator unit 1 0 like consisting of commutator 9 is a commutator segments, the stator 4,
It is composed of a yoke 13, a magnet 12, and the like.

The core 7 is formed by laminating silicon steel sheets having excellent magnetic properties. As shown in FIGS. 2 and 3, an anchor-shaped projection 7a extends in three directions, and a hole 7b is formed in the center thereof. Are formed. A winding 15 is wound around the anchor-shaped protrusion 7a via an insulator 14, and a commutator 9 is inserted into the hole 7b.
The boss portion 8a of the commutator holder 8 that supports is mounted. The boss 8 a is in contact with the upper surface of the bearing 6 via the washer 18. The boss 8a has a bottomed hole 8
b is formed as a bearing portion, and the base end 11b of the support shaft is press-fitted into the hole 8b.

[0011] The magnetic center of the rotor 3, than the magnetic center of the stator 4 is constituted by shifting the arrow P direction opposite force to try to align the rotor 3 to the center of the stator 4 (suction force ) Urges the rotor 3 in the direction of arrow P. In particular, when the rotor 3 becomes an electromagnet by a current supplied from a brush described later, the rotor 3 is further strongly urged in the direction of the arrow P.

On the top surface of the commutator holder 8 is formed a conical portion 8c which is raised in a conical shape.
In c, a commutator 9 composed of a group of conical pieces having a vertex on the rotation center axis L of the support shaft is provided by insert formation.

[0013] commutator 9, there is switching the direction of current flowing through the winding 15, in this embodiment, are the three divided by three pieces are cut groove 20 with a cutter, not shown, A part of the front surface 9a is in contact with a pair of brushes 16 which are connected to a power source (not shown) and which are brushes supported by a holding member 21 fixed inside the lid 5.

The brush 16 transmits a current from a power source (not shown) to the commutator 9 and is shown in FIG.
So as to extend in a direction intersecting with the axial direction of the support shaft 11.
A holding member 21 having a plate-like shape and made of resin as an insulator is provided with a base end on a conical surface 9 of a commutator 9.
It is insert-molded with the same slope and a, Ke
When the lid 5 is attached to the case 2 so as to close the opening of the case 2 , the free end side thereof is provided so as to contact the commutator 9 with a constant pressure.

On the part of the outer periphery of the commutator 9, three electrode terminals 17 extending radially from the commutator holder 8 and integrally formed in three directions are integrally formed. 15 is in contact.

On the other hand, an arc-shaped magnet 12 fixed to the case 2 via a yoke 13 is provided around the core 7. These stators 4 are arranged coaxially with respect to the support shaft 11 with an air gap d provided between the magnet 12 and the core 7. The air gap d is set so as to keep the magnetic flux density large while taking into consideration thermal expansion due to high-speed rotation and long-time operation of the rotor 3. Reference numeral 19 indicates a snap ring.

The operation of the motor 1 configured as described above will be described. When the power is turned on and the current flows from the brush 16 to the winding 15 through the commutator 9, the core 7 is magnetized. At this time, the commutator 9 turns the winding 15
The direction and the phase of the current flowing through the magnet 12 are switched, the magnetic poles formed change as needed, and the rotor 3 rotates with the force repelling the magnetic field of the magnet 12, and the support shaft 11 rotates accordingly.
The attracting force of the magnet 12 always acts on the rotor 3.
And in particular by the current supplied from the brush 16
When the rotor 3 becomes an electromagnet, the force for urging in the direction of arrow P is
It gets even stronger. As a result, the rotor 3 moves upward of the case 2 and rotates away from the washer 18.

[0018] Thus, the commutator 9 formed in a conical shape having an apex on the axis Rotation center line of the support shaft is disposed on top of the commutator holder 8, the support shaft to the boss portion 8a of the commutator holder 8 since the formation of the bottomed hole 8b is a bearing portion for supporting the 11, can be reduced <br/> space occupied with respect to the axial direction of the commutator 9, it is possible to flatten the motor 1.

Further, since the commutator 9 has a conical shape, the clearance angle of the cutter when forming the groove 20 on the surface 9a thereof can be reduced, and the commutator 9 can be prevented from spreading in the radial direction. The peripheral speed of the commutator can be reduced, and the contact surface between the brush 16 and the commutator 9 can be secured.

Further, since the brush 16 is fixed to the holding member 21 formed on the lid 5 in advance so as to be able to press against the conical surface 9a of the commutator 9, after the rotor 3 is attached to the case 2, the lid 5 is attached to the case 2. When the brush 16 and the commutator 9 are mounted so as to close the opening, the pressure contact between the brush 16 and the commutator 9 is completed, so that the motor can be easily assembled. Bearing for supporting the support shaft 11
The bottom 2 of the case 2 where the portion 6 faces the commutator unit 10
a, the support shaft 11 is rotated by the bearing 6 alone.
Support when attaching and detaching the lid 5 and case 2
The shaft 11 does not have to be removed, making it easier to assemble the motor.
Easy to do .

[0021]

According to the present invention, since the bulk of the axial direction and in the axial direction of the commutator can be reduced than the conventional, it is possible to flatten the motor while reducing the motor noise . Brush and rectification just by attaching the lid to the case
Since the pressure contact with the child segment is completed, the motor
Can be easily done. Part of the case facing the commutator unit
The support shaft is rotatably supported only by the bearings
It is not necessary to remove the support shaft when attaching / detaching the lid and case.
As a result, the motor can be more easily assembled.

[Brief description of the drawings]

FIG. 1 is a side sectional view of a flat DC motor showing a first embodiment of the present invention.

FIG. 2 is a plan view of the flat DC motor shown in FIG.

FIG. 3 is a perspective view of a commutator unit which is a main part of the present invention.

[Explanation of symbols]

1 flat type direct current motor 3 rotor (rotor) 8 commutator holder 8b bearing portion (bottomed holes) 9 commutator segments (commutator) 10 commutator unit 11 supporting shaft 16 brush (brush) 21 holding member

Continuation of the front page (58) Field surveyed (Int. Cl. ⁶ , DB name) H02K 13/00 H02K 23/00 H02K 5/14

Claims (2)

(57) [Claims] 1. A DC motor having a commutator unit that rotates integrally with a rotor, comprising: a commutator unit having a conical commutator segment; an opening on one side and supporting the commutator unit on the other side. A case that supports via a shaft, a lid that closes an opening of the case from the axial direction of the support shaft, and a brush that is provided so as to be able to contact the commutator segment, wherein the brush is a shaft of the support shaft. A base side extending so as to intersect with the direction, so that when the opening is closed by the lid, its free end presses along the conical surface of the commutator segment. Characterized by being supported by the lid. 2. The flat DC motor according to claim 1, wherein the support shaft is rotatably supported only by a bearing provided at a portion of the case facing the commutator unit.