JP2007267456A - Commutator of direct-current motor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a commutator of a direct-current motor wherein the output of the direct-current motor is increased by winding a coil with high tension, and the suppression of electrical interruption and the enhancement of performance are also achieved. <P>SOLUTION: The commutator 5 of the direct-current motor is constructed of: a cylindrical insulator 51 annularly fit onto the rotating shaft of the direct-current motor, multiple commutator pieces 52 disposed on the outer circumferential surface of the insulator in the circumferential direction, and hooks 53 on which coils 33 are wound and which are extended from ends of the commutator pieces and radially bent at their tips. The winding position of the terminal wire 33a of a coil in each hook is moved toward the insulator. This movement of the terminal wire winding positions can be achieved by providing an air gap between each hook and the outer circumferential portion of the insulator, and inclining each hook from the mounting portion at the end of a commutator piece toward the insulator. The air gap is constructed by forming a tapered portion 51b whose outside diameter is gradually reduced on the outer circumference of the insulator opposite each hook. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a commutator for a brushed DC motor.

  In a DC motor, for example, a brushed DC motor, a stator (stator) is configured by arranging a magnet in an outer motor case, and a rotor (rotor) having a predetermined air gap (air gap) inside the stator. A structure that is rotatably arranged is common.

  As shown in FIG. 5, the rotor r is mainly configured by surrounding a laminated core r3 in which a coil r2 is wound around a motor shaft r1 and a commutator c (commutator). The laminated core r3 is formed by laminating electromagnetic steel sheets having a plurality of teeth. The commutator c has a plurality of commutator pieces c2 (segments) arranged at a predetermined gap along the outer peripheral surface of the cylindrical insulator c1, and is bent while spreading radially at the end of each commutator piece c2. The hook c3 to be formed is formed. The hook c3 is welded (fused) after the terminal wire r4 of the coil r2 wound around the laminated core r3 is entangled to electrically connect each other. Further, the commutator c is fixed with a varistor ring c4 for preventing electrical noise that circumscribes the outer edge of the hook c3 by welding (soldering).

  The DC motor having the above configuration has recently been strongly demanded to increase the output with the same size. As a method for dealing with this requirement, there is a method of increasing the winding occupation ratio of the coil with respect to the laminated core when the size of the laminated core is not changed. In order to realize this method, it was necessary to wind more coils around the slot of the laminated core with a strong tension. When a coil is wound with such a strong tension, a strong tension is applied to the terminal wire of the coil tangled with the hook, and a so-called flyer method is adopted in which the terminal wire becomes long with respect to the coil winding method. In combination, there is a problem that the hook and the terminal wire are easily broken due to vibration during operation of the DC motor, and the coil and the commutator piece are electrically disconnected.

Patent Document 1 discloses a commutator that improves the strength of a hook. The commutator of this document has a configuration in which the width and thickness are increased from the current state at the base portion of the hook (connection claw) that is bent after connection with the commutator piece.
Japanese Patent Laying-Open No. 2003-9472 (page 5-8, FIG. 2)

  However, the commutator of Patent Document 1 is reduced in damage because the strength of the hook is improved. However, the commutator cannot cope with the disconnection of the terminal wire of the coil, and as a result, the coil and the commutator piece. Has not yet reached a fundamental solution to the problem of electrical disconnection. When a thin wire is used for the coil, the terminal wire is frequently broken.

  In addition, when varistoring for preventing electrical noise is installed, if the outer diameter of the hook is large (currently at least larger than the outer diameter of the commutator), the varistor ring is placed on the outer edge of the hook. The outer diameter of the varistor ring to be installed was increased, and the moment of inertia of the rotor was increased accordingly. The smaller the moment of inertia of the rotor, the better the response and the reduction of vibrations, and the performance of the DC motor is improved.

  Accordingly, the present invention has been made in view of the above problems, and it is possible to wind a coil with a high tension around a slot of a laminated core to increase the output of a DC motor, and to suppress electrical disconnection and improve performance. A direct current motor commutator is also provided.

In order to solve the above problems, the commutator of the direct current motor of the present invention is configured as follows.
That is, a cylindrical insulator (51) mounted around the rotating shaft of the DC motor, a plurality of commutator pieces (52) arranged in the circumferential direction of the outer peripheral surface of the insulator (51), and the commutator pieces ( 52) and a hook (53) that wraps a coil (33) that extends from the end of the wire and has a radially bent tip (33), and a coil in each hook (53). The binding position of the terminal line (33a) of (33) is moved to the insulator side. By this movement, it is possible to reduce the size of the varistor ring (55) that is circumscribed on the outer edge formed by each hook (53) and fixed by welding (soldering).

  Preferably, the binding position of the terminal wire (33a) in each hook (53) is moved toward the insulator so as to be inside the outer edge of the commutator (5).

  In addition, the movement of the binding position of the terminal wire (33a) described above provides a gap (54) between the outer periphery of each hook (53) and the insulator (51), and each hook (53) is connected to the commutator piece. This is realized by inclining toward the insulator side from the attachment portion with the end portion of (52). The gap (54) is preferably formed by forming a tapered portion (51b) whose outer diameter is gradually reduced on the outer peripheral portion of the insulator (51) facing each hook (53). .

  It is desirable to form a recess (53a) that crosses the commutator (5) in the circumferential direction at the attachment portion between each hook (53) and the end of the commutator piece (52). By forming the recess (53a), each hook (53) can be easily bent and inclined from the mounting portion toward the insulator.

  Note that the reference numerals in parentheses described in the claims and the means for solving the above-described problems are added with reference numerals for easy understanding of the configuration of the invention. Of course, it is not limited to the above form.

Since the commutator of the DC motor of the present invention has the above-described configuration, the following effects are exhibited.
That is, even if strong tension acts on the terminal wire of the coil entangled with the hook, the tension can be easily relaxed by moving the hook toward the insulator without changing the conventional winding process and welding process. Therefore, the coil can be wound with stronger tension in the slot of the laminated core, and the winding occupation ratio of the coil with respect to the laminated core can be increased. As a result, it is possible to achieve high output in the same size of the DC motor.

  The outer diameter dimension formed by the outer edge of each hook can be reduced by moving the hook toward the insulator. For this reason, it is possible to reduce the size of the varistor ring disposed on the outer edge of the hook, and it is possible to reduce the cost of the varistor ring. Furthermore, since the size reduction of the varistor ring contributes to the reduction of the moment of inertia of the entire rotor, it is possible to improve the performance such as the responsiveness of the DC motor.

  DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Exemplary embodiments of a commutator of a direct current motor (hereinafter abbreviated as “motor”) according to the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a cross-sectional view showing the structure of the motor of this embodiment example, FIG. 2 is an enlarged perspective view of a main part showing the commutator of this embodiment example, and FIG. 3 is a portion showing the commutator of this embodiment example. It is sectional drawing (A), (B).

  The motor M of the present embodiment mainly includes two magnets 11 for forming a field on the inner peripheral surface of a motor case 1 (annular yoke) having a bottomed cylindrical shape, and a predetermined relationship with the magnet 11. The rotor 3 is disposed so as to be rotatable with a gap, and the opening side of the motor case 1 is closed by the end plate 2.

  The rotor 3 is fixed by a bearing 12, 21 that fixes a laminated core 32 and a commutator 5 around a motor shaft 31 with a coil 33 wound with a predetermined tension, and is arranged on both ends of the motor case 1 and the end plate 2. The shaft is supported. The winding method of the coil 33 is a so-called flyer method in which two slots in the laminated core 32 are wound with a predetermined tension between teeth at a position close to 180 degrees (close to the axial symmetry of the motor shaft). . The terminal wire 33a of the coil 33 is fixed to the commutator 5 by welding (fusing).

  The side surface of the commutator 5 is in contact with the brush 4 fixed to the brush holder 41 so as to be opposed to the commutator 5, thereby energizing the rotor 3. The brush 4 is connected to an electrode 42 extending from the end plate 2.

  The motor shaft 31 protrudes from the motor case 1 at a predetermined length on the side opposite to the end plate to serve as an output shaft. Usually, this output shaft bears a load by connecting a rotating object. The above configuration is the same as that of the prior art.

Next, the configuration of the commutator 5 which is the main point of the present invention will be described in detail.
The commutator 5 is arranged with a predetermined gap along the outer peripheral surface of the cylindrical insulator 51, for example, phenol resin, and the insulator 51 having a plurality of grooves 51 a in the axial direction of the side surface, and the terminal of the coil 33. A commutator piece 52 (segment) made of a plurality of conductive materials (seven in this embodiment) to which the wire 33a is connected, and a varistor ring 55 for preventing electrical noise arranged so as to circumscribe the commutator piece 52; It consists mainly of.

  A hook 53 is integrally formed from the end of each commutator piece 52, 52... Extending in the axial direction of the insulator 51 and bending the tip side toward the radial direction of the commutator 5. The hook 53 is formed to have a narrower width than the commutator piece 52, and a recess 53 a that traverses in the circumferential direction is formed at the attachment portion with the end of the commutator piece 52. Each of the hooks 53, 53,... Is fixed by welding after the terminal wire 33a of the coil 33 is wound around. The coil 33 is wound around the laminated core 32 with a predetermined tension, and the terminal wire 33a of the coil 33 is also welded after being wound around the hook 53 with a tension equivalent to that of the winding.

  Further, as shown in FIG. 3, a tapered portion 51b that gradually decreases in diameter is formed on the outer peripheral portion of the insulator 51 facing the inner peripheral surface side of each of the hooks 53, 53. Therefore, a gap 54 is formed on the outer peripheral surface of each of the hooks 53, 53... And the insulator 51, but the hook 53 is inclined from the attachment portion to the insulator side when welding the tangled terminal wire 33 a. And are bent so as to fill the gap 54 (arrow a). This folding process is easy because the concave portion 53a is formed in the attachment portion of the hook 53.

  The inclination of the hook 53 toward the insulator side not only moves the binding position of the terminal wire 33a in the hook 53 to the insulator side and the laminated core side, but also reduces the outer diameter dimension formed by the outer edge of each hook 53. Yes.

  Further, the movement of the binding position of the terminal line 33a in the hook 53 enables the tension acting on the terminal line 33a to be relaxed. That is, only the tension acting on the portion of the terminal wire 33a can be relaxed after the coil 33 is wound with a tension stronger than usual in order to increase the winding occupation ratio in the laminated core 32. As a result, breakage of the hook 53 after motor assembly and disconnection of the terminal wire 33a can be suppressed.

  Further, after the hook 53 is inclined, the outer edge dimension formed by each of the hooks 53, 53,... Is reduced, so that the size of the varistor ring 55 that is circumscribed and welded (soldered) can be reduced. In the present embodiment example. As described above, the outer diameter dimension formed by the outer edges of the hooks 53, 53... Is set to be smaller than the outer diameter dimension of the commutator 5. Therefore, the binding position of the terminal line 33 a in the hook 53 is also inside the outer edge of the commutator 5.

The size reduction of the varistor ring 55 not only reduces the cost of the varistor ring 55 but also reduces the moment of inertia of the entire rotor, and thus greatly contributes to the improvement of the motor characteristics.
[Possibility of other embodiments]

  In the above embodiment, the gap 51 is obtained between the hooks 53, 53,... By forming the tapered portion 51b in the insulator 51. However, the present invention is not limited to this embodiment. As long as the space is bent, the space may be secured. For example, as shown in FIG. 4, only the inclined space 51 c in which the hook 53 is inclined and contacts the outer peripheral portion of the insulator 51 may be formed. In this case, since the portion other than the inclined space is thick, the rigidity of the insulator 51 is improved.

It is sectional drawing which shows the structure of the motor of the example of this embodiment. It is a principal part expansion perspective view which shows the commutator of the example of this embodiment. It is a fragmentary sectional view (A) and (B) which show the commutator of this embodiment example. It is a perspective view which shows the commutator of other example embodiments. It is a side view which shows the conventional commutator.

Explanation of symbols

M Motor 1 Motor case 11 Magnet 12 Bearing 2 End plate 21 Bearing 3 Rotor 31 Motor shaft 32 Stacked core 33 Coil 33a Terminal wire 4 Brush 41 Brush holder 42 Electrode 5 Commutator 51 Insulator 51a Groove 51b Taper 51c Inclined space 52 Commutator piece 53 Hook 53a Recessed part 54 Air gap 55 Varistoring r Rotor (conventional example)
r1 motor shaft r2 coil r3 laminated core r4 terminal line c commutator (conventional example)
c1 insulator c2 commutator piece c3 hook c4 varistor ring

Claims (5)

A cylindrical insulator (51) mounted around the rotating shaft of the DC motor, a plurality of commutator pieces (52) arranged in the circumferential direction of the outer peripheral surface of the insulator (51), and the commutator pieces (52) A DC motor commutator (5) consisting of a hook (53) that ties a terminal wire (33a) of a coil (33) that extends from the end of the coil and that has a radially bent tip (33).
A commutator for a DC motor, wherein the binding position of the terminal wire (33a) of the coil (33) in each hook (53) is moved to the insulator side. The binding position of the terminal wire (33a) of the coil (33) in each hook (53),
The commutator of a DC motor according to claim 1, wherein the commutator is moved toward the insulator so as to be inside the outer edge of the commutator (5). The binding position of the terminal wire (33a) of the coil (33) in each hook (53),
A gap (54) is provided between the outer peripheries of the hooks (53) and the insulator (51), and the hooks (53) are inclined toward the insulator side from the attachment portion with the end of the commutator piece (52). The commutator of a DC motor according to claim 1 or 2, wherein the commutator is moved by means of the above. The gap (54) between the outer periphery of each hook (53) and insulator (51) is
The commutator for a DC motor according to claim 3, wherein a taper portion (51b) is formed on the outer peripheral portion of the insulator (51) facing each hook (53). In the attachment portion between each hook (53) and the end of the commutator piece (52),
The commutator for a DC motor according to claim 1 or 3, wherein a concave portion (53a) is formed that crosses the commutator (5) in the circumferential direction.

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