JP2017073950A - Brushed dc motor and method for manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a brushed DC motor the generation of vibration of which can be suppressed.SOLUTION: The brushed DC motor comprises: a brush 20 coming in contact with a commutator; a terminal 28 having an attachment portion 28a and a fixing portion 28b connected to the attachment portion 28a; and a bracket 30 to which the terminal 28 is fixed. The fixing portion 28b of the terminal 28 is fixed on the bracket 30 so as to be force-fitted into a groove portion 32 formed in the bracket 30. The brush 20 is attached to the attachment portion 28a of the terminal 28 so as to have flexibility. The bracket 30 has a supporting portion 37 for supporting the attachment portion 28a while being in contact with a part of the attachment portion 28a.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a brushed DC motor and a method of manufacturing a brushed DC motor, and more particularly, to a brushed DC motor and a brushed DC motor having a structure in which a terminal to which a brush arm is attached is press-fitted into a bracket and fixed. It relates to a manufacturing method.

  Some DC motors with a brush have a structure in which a terminal to which a brush arm is attached is fitted and fixed to a bracket.

  Patent Document 1 below discloses a motor structure in which an adhesive material made of a water-soluble acrylic emulsion is applied as a damper material to the base of a brush arm in order to attenuate vibrations of the brush arm.

  Patent Document 2 below discloses a motor structure in which a fixed end portion of a brush base, which is a terminal portion, is fixed so as to be sandwiched between a resin case lid and a protrusion formed integrally with the case lid. ing.

JP-A-7-194067 JP 2006-166646 A

  In the brushed DC motor as described above, the brush arm is fastened to the terminal. Since the brush arm contacts the commutator, the brush arm needs to be held on the terminal so as to be flexible (like a cantilever beam). That is, the brush arm is held in a state where a part thereof is fastened to the terminal without being in contact with other members and capable of vibrating. In this case, the fastening portion of the terminal with the brush arm is a free end that does not contact other members.

  When vibration is generated in the brush arm, motor vibration and noise may be generated. In order to prevent this, for example, a vibration absorbing material such as a vibration isolating material is used so that vibration is absorbed while the flexibility of the brush arm is maintained.

  However, even when a vibration absorbing material is used, vibration generated in the brush arm is not completely absorbed. Vibration that has not been absorbed by the brush arm is transmitted to the free end of the terminal. As a result, when the vibration at the free end of the terminal increases, the vibration is transmitted to the bracket of the motor, which may cause vibration of the entire motor.

  Regarding such problems, Patent Documents 1 and 2 do not disclose effective solutions.

  In the structure described in Patent Document 1, there are problems that man-hours and time required for preparing an adhesive material or for applying and drying the adhesive material on the base of the brush arm are required. In addition, there is a problem that the adhesive material may change with time and the effect of absorbing vibration may be reduced.

  The structure described in Patent Document 2 is such that the terminal is completely fixed by sandwiching the terminal between a resin case lid and a protrusion, and the brush arm as described above is attached to the terminal so as to have flexibility. It cannot be applied to the structure to be held.

  This invention was made in order to solve such a problem, and it aims at providing the manufacturing method of DC motor with a brush and generation | occurrence | production of a DC motor with a brush which can suppress generation | occurrence | production of a vibration.

  In order to achieve the above object, according to an aspect of the present invention, a brushed DC motor includes a brush that contacts a commutator, a terminal having a fixing part connected to the mounting part and the mounting part, and a bracket to which the terminal is fixed. The terminal fixing portion is fixed to the bracket while being press-fitted into a groove formed in the bracket, and the brush is attached to the terminal attachment portion so as to have flexibility, A bracket has a support part which contacts a part of attachment part and supports an attachment part.

  Preferably, the bracket is made of resin, and the support portion has a raised protrusion shape and is in contact with a part of the attachment portion.

  Preferably, the support part has a shape that interferes with the terminal, and a part of the support part is in contact with a part of the attachment part in a state of being plastically deformed or elastically deformed from a state when the bracket is formed. .

  Preferably, the mounting portion is plate-shaped, the brush is plate-shaped, and the brush has a portion of the plate surface opposite to the side where the portion contacting the commutator is provided. It is attached to the attachment portion in contact with the surface of the first plate, and the support portion comes into contact with the second plate surface of the attachment portion on the back side of the first plate surface.

  Preferably, the brush arm is attached to the attachment portion in a state where it is crimped to the terminal.

  According to another aspect of the present invention, a method for manufacturing a brushed DC motor having a structure in which a terminal to which a brush is attached is fixed to a resin bracket is a first step of attaching the brush to a terminal attachment portion. And after the first step, a second step of press-fitting a fixed portion connected to the mounting portion of the terminal into a groove formed in the bracket, and the bracket includes a support portion that supports the mounting portion. And a part of the support part is plastically deformed by being pressed against a part of the attachment part in the second step, and is in contact with a part of the attachment part.

  According to these invention, the support part of a bracket contacts a part of attachment part to which the brush arm is attached, and supports an attachment part. Therefore, it is possible to provide a brushed DC motor that can suppress the occurrence of vibration.

It is a sectional side view which shows the DC motor with a brush in one of the embodiment of this invention. It is a perspective view which shows the structure of a bracket unit partially. It is sectional drawing which shows the structure of a bracket unit partially. It is sectional drawing of the bracket in the state where the terminal is not press-fitted. It is a perspective view which shows partially the bracket unit in the state where the terminal is not press-fitted. It is sectional drawing explaining the attachment structure to the bracket of a terminal.

  Hereinafter, the brushed DC motor according to the embodiment of the present invention will be described.

  [Embodiment]

  FIG. 1 is a side sectional view showing a brushed DC motor 1 according to an embodiment of the present invention.

  As shown in FIG. 1, a brushed DC motor (hereinafter sometimes simply referred to as a motor) 1 is roughly composed of a frame assembly 1a and an armature assembly rotatably supported with respect to the frame assembly 1a. 3b (hereinafter sometimes simply referred to as an amateur) 1b.

  The amateur assembly 1b has a rotating shaft (shaft) 2, an armature portion 4, a commutator portion 6, and the like. The amateur part 4 is attached to the rotary shaft 2. The amateur part 4 includes an armature core 5 having a plurality of salient poles projecting in the radial direction and a winding (not shown) wound around each salient pole. The commutator portion 6 is provided in the vicinity of the base end portion (the right end portion in FIG. 1) of the rotating shaft 2 and rotates together with the rotating shaft 2. The commutator 6 includes a commutator 7 that contacts the brush 20 attached to the frame assembly 1a as described later.

  The frame assembly 1a includes a frame 10, a bracket 30, a plate 41, a magnet 50, and the like.

  The frame 10 has a cylindrical shape in which one end portion is blocked so that the tip end portion (the left end portion in FIG. 1) of the rotating shaft 2 protrudes. The opening of the other end portion (the right end portion in FIG. 1) of the frame 10 is blocked by the plate 41. An amateur 1b is housed in a frame constituted by the frame 10 and the plate 41. The amateur 1b is housed so that one end of the rotating shaft 2 protrudes from the frame 10. Bearings 18 and 19 are held at one end of the frame 10 and the center of each of the plates 41. The rotary shaft 2 is held rotatably with respect to the frame 10 by two bearings 18 and 19.

  The plate unit 41, the bracket 30, the terminal 28, the brush 20, and the bearing 19 constitute a bracket unit 40. That is, the bracket 30 is attached to the inside of the plate 41. The bracket 30 is made of resin. The bracket 30 holds a terminal 28 to which an external current is supplied. The brush 20 is attached to the terminal 28 as described later. A pair of terminals 28 and brushes 20 are provided.

  FIG. 2 is a perspective view partially showing the structure of the bracket unit 40.

  In FIG. 2, a support structure for one brush 20 of the bracket unit 40 is shown. The commutator 7 is located in the vicinity where the bearing 19 is provided.

  As shown in FIG. 2, in this embodiment, the brush 20 has a plate-like brush arm 21. The brush arm 21 is made of a metal plate. The brush 20 is held by a bracket 30 via a terminal 28 such that a contact portion 25 provided in the vicinity of the tip of the brush arm 21 contacts the commutator 7. The brush arm 21 generally has a rectangular plate shape in which one direction in a plane perpendicular to the rotation shaft 2 is the longitudinal direction and the direction parallel to the rotation shaft 2 is the width direction.

  One sheet-like vibration isolator 27 is provided on a plate surface 21b (hereinafter, also referred to as a surface 21b) on the side of the brush arm 21 where the contact portion 25 is provided (that is, the commutator 7 side). Is affixed. The brush arm 21 has a plurality of brush pieces each formed so as to have flexibility, and the vibration isolating material 27 is stuck over each brush piece.

  The brush 20 is used in a state where the contact portion 25 is in contact with the commutator 7 and slightly bent from the natural state. The brush arm 21 is held by the terminal 28 so as to be flexible (like a cantilever).

  That is, the terminal 28 has an attachment part 28a to which the brush arm 21 is attached and a fixing part 28b connected to the attachment part 28a. In the present embodiment, the terminal 28 is formed by bending one metal plate, and the attachment portion 28a and the fixing portion 28b are plate-shaped. The attachment portion 28a is bent with respect to the fixed portion 28b, and the distance from the attachment portion 28a to the commutator 7, that is, the length of the brush 20 is secured long.

  The bracket 30 has a groove portion 32 formed so as to hold the fixing portion 28 b of the terminal 28. The groove 32 is formed such that the axial direction of the rotary shaft 2 is the depth direction. The terminal 28 is fixed to the bracket 30 with the fixing portion 28 b being press-fitted into the groove portion 32.

  FIG. 3 is a cross-sectional view partially showing the structure of the bracket unit 40.

  In FIG. 3, a cross section of the bracket 30 passing through a portion perpendicular to the rotation shaft 2 and provided with the terminal 28 is shown.

  As shown in FIG. 3, the brush arm 21 is attached to the attachment portion 28 a of the terminal 28 at the connection portion 21 a near the end portion on the opposite side in the longitudinal direction from the side where the contact portion 25 is provided. The brush arm 21 has a first plate surface 28d (hereinafter, referred to as a part of a plate surface 21c (hereinafter also referred to as a back surface 21c) opposite to the surface 21b on which the contact portion 25 is provided. , And may be attached to the attachment portion 28a.

  The brush arm 21 is attached to the attachment portion 28a while being crimped to the terminal 28. For example, the caulking projection 22 is formed from the surface 21b side of the brush arm 21 in a state where the caulking projection 22 formed on the attachment portion 28a passes through a hole (not shown) formed in the connecting portion 21a of the brush arm 21. By being crushed, the brush arm 21 is caulked to the terminal 28 and fixed. In addition, the caulking protrusion 22 is not formed, and both may be caulked by using a metal fitting such as a rivet disposed so as to penetrate the connecting portion 21a and the attachment portion 28a.

  With such an attachment structure, the brush arm 21 becomes a fixed end where the connecting portion 21a, which is one end portion in the longitudinal direction, is supported by the attachment portion 28a, and the other end portion in the longitudinal direction where the contact portion 25 is provided is a free end. It becomes a cantilever beam. That is, the brush arm 21 is attached to the attachment portion 28a so as to have flexibility. Therefore, when the commutator 7 rotates with the rotation of the rotating shaft 2, the state in which the contact portion 25 remains in contact with the commutator 7 is appropriately maintained.

  Here, in the present embodiment, as shown in FIG. 2, a support portion 37 is formed on the bracket 30. The support portion 37 has a protruding shape that protrudes from the vicinity of the attachment portion 28a toward the attachment portion 28a so as to contact the vicinity of the portion where the brush arm 21 is caulked. In the present embodiment, a second plate surface 28c (hereinafter also referred to as a back surface 28c) on the back side of the surface 28d of the attachment portion 28a faces a part of the inner wall surface 30d of the bracket 30. The support portion 37 protrudes from the inner wall surface 30d toward the attachment portion 28a.

  FIG. 4 is a cross-sectional view of the bracket 30 in a state where the terminal 28 is not press-fitted. FIG. 5 is a perspective view partially showing the bracket unit 40 in a state where the terminal 28 is not press-fitted.

  4, the same cross section as that shown in FIG. 3 is shown. FIG. 5 is a perspective view seen from an angle corresponding to the perspective view shown in FIG.

  As shown in FIG. 4, the support portion 37 protrudes from the inner wall surface 30 d so as to form a substantially triangular shape when viewed from a direction parallel to the rotation axis 2. As shown in FIG. 5, the support portion 37 protrudes from the inner wall surface 30 d over substantially the entire area of the inner wall surface 30 d in a direction parallel to the rotation shaft 2.

  Note that a chamfered portion 37 a is formed at an end portion of the support portion 37 near the tip end portion of the rotating shaft 2. The chamfered portion 37a is a portion inclined with respect to the end surface on the distal end side of the rotating shaft 2 of the bracket 30 so as to approach the proximal end portion of the rotating shaft 2 as it approaches the protruding end portion 37b away from the inner wall surface 30d. .

  As shown in FIG. 4, the support portion 37 has a protruding end portion 37 b when the bracket 30 is molded. In the present embodiment, the protruding end portion 37 b has a shape that interferes with the terminal 28 fixed to the bracket 30. As shown in FIG. 3, in the state where the terminal 28 is fixed to the bracket 30, the support portion 37 is plastically deformed in the vicinity of the protruding tip portion including the protruding end portion 37 b from the state when the bracket 30 is molded. In the state, it contacts the back surface 28c of the mounting portion 28a.

  FIG. 6 is a cross-sectional view illustrating a structure for attaching the terminal 28 to the bracket 30.

  The cross section shown in FIG. 6 corresponds to the cross section along line AA in FIG. In FIG. 6, the illustration of the plate 41 is omitted. In FIG. 6, the left-right direction indicates the longitudinal direction of the rotating shaft 2, and the right side is the tip side of the rotating shaft 2.

  At the time of manufacturing the motor 1, the brush 20 and the terminal 28 are attached to the bracket 30 by the following two procedures.

  That is, first, the connecting portion 21 a of the brush arm 21 is attached to the attaching portion 28 a of the terminal 28. At this time, the caulking protrusion 22 disposed so as to penetrate the connecting portion 21a is crushed from the surface 21b side of the brush arm 21, and the brush arm 21 is caulked to the mounting portion 28a (first step).

  Second, the fixing portion 28b of the terminal 28 is press-fitted into the groove portion 32 formed in the bracket 30 (second step). Thereby, the fixing portion 28 b is fixed to the bracket 30. The brush 20 attached to the attachment portion 28 a is supported by the bracket 30 via the terminal 28.

  Here, as shown in FIG. 6, in the state when the bracket 30 is formed, the vicinity of the portion including the protruding end portion 37b of the support portion 37 formed on the bracket 30 is at a position where it interferes with the mounting portion 28a. is there. Therefore, in the second step described above, as the fixing portion 28b is press-fitted, the vicinity of the tip portion of the support portion 37 is pressed downward by the back surface 28c of the mounting portion 28a. Therefore, in the state in which the fixing portion 28b is press-fitted, the vicinity of the tip portion of the support portion 37 is plastically deformed from the state before the press-fitting and becomes a crushed state. At this time, the attachment portion 28a is also slightly elastically deformed from the natural state. Therefore, the attachment portion 28a is pressed against the support portion 37 in a state of being deformed by the restoring force of the attachment portion 28a, and the state where the support portion 37 is in contact with the attachment portion 28a is maintained.

  In the present embodiment, since the support portion 37 is provided with a chamfered portion 37a, when the fixing portion 28b is press-fitted, the mounting portion 28a extends along the chamfered portion 37a so that the support portion 37 protrudes. The end 37b is reached. Therefore, the second step described above can be performed smoothly.

  In the brushed DC motor 1 configured as described above, the support portion 37 of the bracket 30 contacts the back surface 28c of the attachment portion 28a to which the brush arm 21 is attached, and supports the attachment portion 28a. That is, the attachment portion 28a of the terminal 28 that is a free end with respect to the fixed portion 28b is supported by contacting the support portion 37 in the present embodiment. Therefore, even if the vibration of the brush 20 is transmitted from the brush arm 21 to the mounting portion 28a, the vibration at the mounting portion 28a is suppressed so as not to increase. Therefore, the vibration of the terminal 28 can be suppressed and the vibration of the motor 1 can be suppressed.

  In the present embodiment, the support portion 37 is in contact with the mounting portion 28a in a state where the support portion 37 is plastically deformed by press-fitting the terminal 28 into the bracket 30. Thus, the mounting portion 28a is urged to be maintained in a relatively large elastically deformed state from the natural state, and the force with which the mounting portion 28a and the support portion 37 are pressed against each other is increased. Therefore, the attachment portion 28a is further less likely to vibrate, and the vibration of the motor 1 is suppressed.

  Since the support portion 37 is provided with the chamfered portion 37a, the terminal 28 can be easily press-fitted into the bracket 30. Therefore, the manufacturing cost of the motor 1 can be kept low.

  [Others]

  In the above embodiment, the support portion is plastically deformed before and after the fixing portion is press-fitted into the bracket, but is not limited thereto. The support part should just be formed so that a support part may contact an attachment part in the state in which the terminal is attached to the bracket. For example, the support portion may be configured to keep the terminal elastically deformed by contacting the attachment portion when the terminal is attached to the bracket. Even in such a case, the same effect as described above can be obtained.

  Further, the number and shape of the support portions are not limited to those described above. Two or more support portions may be provided so as to contact the attachment portion and support the attachment portion, or may not be formed over the entire width direction of the attachment portion. For example, when the length of the attachment portion in the longitudinal direction is long, the support portions may be arranged at a plurality of locations.

  The support portion may be formed on the bracket by attaching a member molded separately from the bracket to the bracket.

  The shape of the terminal or brush is not limited to the above. The terminal is not limited to the shape in which the attachment portion is bent with respect to the fixed portion, and may be gently curved from the fixed portion to the attachment portion or may be formed in a straight line shape. The attachment structure of the brush arm to the terminal is not limited to that by caulking, and may be another method such as welding or welding.

  The above embodiment should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

DESCRIPTION OF SYMBOLS 1 DC motor with brush 1a Frame assembly 1b Amateur assembly 2 Rotating shaft 7 Commutator 20 Brush 21 Brush arm 21a Connection part 21b Front surface 21c Back surface 22 Caulking protrusion 25 Contact part 28 Terminal 28a Attachment part 28b Fixing part 28c 2 plate surface 28d first plate surface of mounting portion 30 bracket 30d inner wall surface 32 groove portion 37 support portion 37a chamfered portion 37b protruding end portion 40 bracket unit

Claims (6)

A brush that contacts the commutator;
A terminal having a mounting portion and a fixed portion connected to the mounting portion;
A bracket to which the terminal is fixed;
The fixed portion of the terminal is fixed to the bracket in a state of being press-fitted into a groove formed in the bracket,
The brush is attached to the attachment portion of the terminal so as to have flexibility,
The bracket is a DC motor with a brush having a support portion that contacts a part of the attachment portion and supports the attachment portion. The bracket is made of resin,
The brushed DC motor according to claim 1, wherein the support portion has a protruding shape and is in contact with a part of the attachment portion.   The support part has a shape that interferes with the terminal, and a part of the support part comes into contact with a part of the attachment part in a state of being plastically deformed or elastically deformed from a state when the bracket is formed. The brushed DC motor according to claim 1 or 2. The mounting portion is plate-shaped,
The brush is plate-shaped,
The brush is attached to the attachment portion in a state where a part of the plate surface opposite to the side where the portion that contacts the commutator is provided is in contact with the first plate surface of the attachment portion. ,
4. The brushed DC motor according to claim 1, wherein the support portion is in contact with a second plate surface of the mounting portion on the back side of the first plate surface. 5.   The brushed DC motor according to any one of claims 1 to 4, wherein the brush is attached to the attachment portion in a state of being caulked to the terminal. A method of manufacturing a brushed DC motor having a structure in which a terminal to which a brush is attached is fixed to a resin bracket,
A first step of attaching the brush to the attachment portion of the terminal;
After the first step, a second step of press-fitting a fixed portion connected to the mounting portion of the terminal into a groove formed in the bracket,
The bracket has a support part for supporting the attachment part,
In the second step, a part of the support part is plastically deformed by being pressed against a part of the attachment part and is in contact with a part of the attachment part.

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