JP2005223974A - Fixing structure for brush in dc motor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide the fixing structure for a brush in a DC motor, capable of readily fixing the brush to a brush holder. <P>SOLUTION: In the fixing structure of a brush 26, coming into resilient contact with the commutator 24 of the armature 22 in a DC motor 14, a tubular brush holder 30 is fixed to the inner circumferential side of a frame 12, a holder shank 36 is inserted into the through hole 34 of the brush holder 30, the brush 26 is inserted into the holder shank 36, one end part of the brush 26 is exposed from the brush holder 30, and the other end of the brush 26 is connected via a spring 38 with a metal supporting plate 40 secured by means of a pair of claws 44 and 44 projecting from the edge part of the through hole 34. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a brush mounting structure that elastically contacts a commutator of an armature in a DC motor.

  In a motor such as a disc grinder or a variable speed drill, a direct current motor having a simple structure is used as a drive source.

The DC motor needs to be provided with a brush in order to pass electricity through the armature commutator. As such a brush mounting structure, for example, a structure for mounting a brush inside a brush holder is well known (Patent Document 1).
JP 2003-260676 A

  As a structure for attaching the brush to the brush holder as described above, for example, a spring is attached to the brush, the spring is attached to a metal support plate, and the support plate is attached to the brush holder.

  At this time, it is difficult to attach the support plate to the brush holder due to the influence of the spring, and it is necessary to close the brush cap while pressing the support plate against the elastic force of the spring. There is a problem that it can not be inserted well.

  In addition, if the brush cannot be inserted into the brush holder well, it becomes defective and causes problems such as sparks.

  Therefore, in view of the above problems, the present invention provides a brush attachment structure that allows a brush to be easily attached to a brush holder.

  According to a first aspect of the present invention, in the brush mounting structure that elastically contacts the armature commutator in the DC motor, a cylindrical brush holder is mounted on the inner peripheral side of the frame of the DC motor, and the through hole of the brush holder A cylindrical metal holder shank is inserted inside, a brush is inserted inside the holder shank, and one end of the brush is exposed from the tip of the brush holder and the holder shank and elastically contacts the commutator. The other end of the brush is connected to a metal support plate via a spring, and the support plate is fixed by a pair of claws protruding to the edge of the through hole. The brush mounting structure in the DC motor is characterized by being covered with the through hole.

  According to a second aspect of the present invention, in the brush mounting structure that elastically contacts the armature commutator in the DC motor, a cylindrical brush holder is mounted on the inner peripheral side of the frame of the DC motor, and the through hole of the brush holder A cylindrical metal holder shank is inserted inside, a brush is inserted inside the holder shank, and one end of the brush is exposed from the tip of the brush holder and the holder shank and elastically contacts the commutator. The other end of the brush is connected to a metal support plate via a spring, and a hole opening in the support plate is fitted into a protrusion protruding from the edge of the through hole. A brush mounting structure in a DC motor, wherein the brush holder covers the through hole of the brush holder.

  According to a third aspect of the present invention, the holder shank protrudes from the tip of the brush holder, a ring-shaped connecting member is fitted to the outside of the protruding holder shank, a lead wire is connected to the connecting member, and the lead 3. The brush mounting structure for a DC motor according to claim 1, wherein the wire is electrically connected to a DC power source.

  The invention according to claim 4 is the brush mounting structure according to claim 1 or 2, wherein the DC motor is built in an electric tool, and the frame is integrated with a frame of the electric tool. It is.

  A brush mounting structure in the DC motor of the invention according to claim 1 will be described.

  First, the brush, spring, and support plate are fixed together. A holder shank is inserted into the through hole of the brush holder.

  Next, the brush in which the spring and the support plate are integrated as described above is inserted into the holder shank, and the brush is exposed from the tip of the brush holder.

  Next, the support plate is fixed with a claw protruding from the edge of the through hole of the brush holder, and the support plate is placed over the through hole of the brush holder. In this case, the support plate is fixed by the pair of claw portions, so that the support plate can be easily attached even if there is an elastic force of the spring.

  As described above, with the brush mounting structure according to the first aspect of the present invention, the brush can be easily attached to the brush holder.

  A brush mounting structure in a DC motor according to a second aspect of the present invention will be described.

  First, the brush, spring, and support plate are fixed together. A holder shank is inserted into the through hole of the brush holder.

  Next, the brush in which the spring and the support plate are integrated as described above is inserted into the holder shank, and the brush is exposed from the tip of the brush holder.

  Next, a hole opening in the support plate is fitted into the protrusion protruding from the edge of the through hole, and the support plate covers the through hole of the brush holder. In this case, the support plate can be easily attached even if there is an elastic force of the spring by fitting the support plate with the protrusion and the hole.

  Thus, with the brush mounting structure of the invention according to claim 2, the brush can be easily attached to the brush holder.

  In the brush mounting structure in the direct current motor according to the third aspect of the present invention, the brush, the direct current power supply, Can be electrically connected.

  The brush mounting structure in the DC motor of the invention according to claim 4 is suitable for the brush mounting structure in an electric tool because the mounting structure is simple as described above.

(First embodiment)
Hereinafter, a first embodiment of the present invention will be described with reference to FIGS.

(1) Structure of Electric Tool 10 The electric tool 10 of the present embodiment is a variable speed drill as shown in FIG. 4 and includes a DC motor 14 and a gear box 16 built in a frame 12 of the electric tool 10 and a chuck. 18 is connected. A drill 20 is fixed to the chuck 18.

  The DC motor 14 includes a stator made of permanent magnets and an armature 22, and the armature 22 is provided with a commutator 24.

  As shown in FIG. 3, a pair of upper and lower mounting cylinders 28 protrude from the frame 12 toward the inner peripheral side of the frame 12 at the upper and lower portions inside the frame 12.

  The distal end portion of the attachment tube portion 28 is opened, and the brush holder 30 is inserted into the attachment tube portion 28. The brush holder 30 will be described in detail later.

  After the brush holder 30 is inserted into the mounting tube portion 28, the cap holder 32 is fitted into the mounting tube portion 28 from outside to fix the brush holder 30.

  As a result, the pair of upper and lower brushes 26 and 26 are elastically contacted with the commutator 24.

(2) Brush 26 Mounting Structure As shown in FIG. 1, the brush holder 30 is provided with a through hole 34 having a rectangular planar shape at the center thereof, and penetrates from the base to the tip. A rectangular metal holder shank 36 having substantially the same shape as the through hole 34 is fitted inside the rectangular through hole 34. As shown in FIG. 1, the holder shank 36 is fitted from the base (upper surface in FIG. 1) of the brush holder 30, protrudes from the distal end (lower in FIG. 1) of the brush holder 30, and the distal end of the holder shank 36. Is exposed from the brush holder 30.

  A structure for attaching the brush 26 to the brush holder 30 having the holder shank 36 will be described based on the order of attachment.

  As shown in FIG. 1, one end of a coiled spring 38 is attached to a brush 26 made of rectangular parallelepiped carbon, and a support plate (pigtilt support) 40 is attached to the other end of the spring 38. As shown in FIG. 1, the support plate 40 has a circular shape, and has a shape in which rectangular extending portions 42 protrude from both ends thereof. Although not shown in FIG. 1, a pigtail wire for electrically connecting the brush 26 and the metal support plate 40 is attached along the spring 38 between the support plate 40 and the brush 26. It has been.

  After the brush 26, the spring 38, and the support plate 40 are integrated as described above, the brush 26 is inserted into the holder shank 36, and the brush 26 is exposed from the tip of the holder shank 36.

  As shown in FIG. 1, a pair of claw portions 44 is provided at the edge of the through hole 34 in the brush holder 30. As shown in FIG. 2, the claw portion 44 has an L-shape, and is configured to be fitted and fixed to an inverted L-shaped insertion portion of the pair of claw portions 44 and 44 while rotating the support plate 40. . That is, the pair of claw portions 44, 44 has a shape that supports each side of the pair of extending portions 42 of the support plate 40. Thus, by supporting the extended portions 42 and 42 of the support plate 40 by the pair of claw portions 44 and 44, the support plate 40 can be attached to the base portion of the brush holder 30 against the elastic force of the spring 38. Therefore, the cap 32 described above can be easily covered.

  After attaching the brush 26 as described above, the ring-shaped connecting member 46 is put on the holder shank 36 protruding from the brush holder 30. A lead wire 48 is connected to the connecting member 46, and the lead wire 48 is connected to a DC power source of the electric tool 10.

  As described above, the brush 26 can be easily attached to the brush holder 30, and the DC power source and the brush 26 can be easily connected by the connecting member 46.

(Second Embodiment)
The attachment structure of the brush 26 of 2nd Embodiment is demonstrated based on FIG.

  In the first embodiment, the support plate 40 is attached by the pair of claw portions 44, 44, but in this embodiment, the holes 50, 50 are provided in the pair of extending portions 42 of the support plate 40 as shown in FIG. 5. A pair of protrusions 52, 52 project from the edge of the through-hole 34 of the brush holder 30, and the hole 50 is fitted into the protrusion 52, so that the support plate 40 is attached to the base of the brush holder 30. Install.

  Even in the second embodiment, since the support plate 40 can be attached to the base of the brush holder 30 against the elastic force of the spring 38, the attaching operation is simplified.

(Example of change)
In the above-described embodiment, the speed change drill has been described as the electric tool 10, but is not limited thereto, and other electric tools may be used, for example, a disc grinder.

  The brush mounting structure in the DC motor of the present invention is preferably used for a DC motor in an electric tool.

It is a disassembled perspective view of the brush holder, holder shank, brush, support plate, etc. of 1st Embodiment. It is a top view of a support plate and a brush holder similarly. It is a longitudinal cross-sectional view of an electric tool. It is a side view of an electric tool. It is a disassembled perspective view of the brush holder, holder shank, brush, support plate, etc. of 2nd Embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Electric tool 12 Frame 14 DC motor 22 Armature 24 Commutator 26 Brush 28 Mounting cylinder part 30 Brush holder 32 Cap 34 Through-hole 36 Holder shank 38 Spring 40 Support plate 42 Extension part 44 Claw part 46 Connection member 48 Lead wire

Claims (4)

In the mounting structure of the brush elastically contacting the armature commutator in the DC motor,
A cylindrical brush holder is attached to the inner peripheral side of the frame of the DC motor,
A cylindrical metal holder shank is inserted inside the through hole of the brush holder,
A brush is inserted inside the holder shank,
One end of the brush is exposed from the tip of the brush holder and holder shank and elastically contacts the commutator,
The other end of the brush is connected to a metal support plate via a spring,
A structure for mounting a brush in a DC motor, wherein the support plate is fixed by a pair of claw portions protruding from an edge portion of the through hole, and the support plate is put on the through hole of the brush holder. . In the mounting structure of the brush elastically contacting the armature commutator in the DC motor,
A cylindrical brush holder is attached to the inner peripheral side of the frame of the DC motor,
A cylindrical metal holder shank is inserted inside the through hole of the brush holder,
A brush is inserted inside the holder shank,
One end of the brush is exposed from the tip of the brush holder and holder shank and elastically contacts the commutator,
The other end of the brush is connected to a metal support plate via a spring,
A brush in a direct current motor, wherein a hole projecting from the edge of the through hole is fitted into a hole opening in the support plate, and the support plate is placed over the through hole of the brush holder. Mounting structure. The holder shank protrudes from the tip of the brush holder;
A ring-shaped connecting member is fitted on the outside of the protruding holder shank,
A lead wire is connected to the connection member,
The brush mounting structure for a DC motor according to claim 1, wherein the lead wire is electrically connected to a DC power source. The DC motor is built in the electric tool,
The brush mounting structure for a DC motor according to claim 1, wherein the frame is integrated with a frame of the electric tool.

Images