JP2008136276A - Motor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a motor so constructed that chattering is reduced. <P>SOLUTION: In the motor 1, a commutator piece main body 14 is so constructed that the following is implemented: the front end 14a of its outer circumferential surface of the main body 14 in the direction S of rotation of a shaft 7 is positioned on a reference circle A on the basis of a rotation center P; and the rear end 14b of its outer circumferential surface in the direction S of rotation of the shaft 7 is so disposed that, when a brush piece 20 constructed of a leaf spring abuts on the front end 14a of the commutator piece main body 14, the rear end abuts on the brush piece 20. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a small motor, and more particularly to a motor having a commutator for reversing a current flowing in a rotor coil.

  As shown in FIG. 9, the commutator piece 100 includes three commutator pieces 101 having a uniform thickness arranged around the sleeve 102 at equal intervals, and each commutator piece 101 is fixed to the shaft 104. The sleeve 102 is fixed so as to be in close contact with the surface of the sleeve 102. And the outer peripheral surface of each commutator piece 101 is arrange | positioned so that a substantially perfect circle may be drawn with respect to a rotation center. The leaf spring-like brush piece 103 extends in the tangential direction so as to contact the commutator piece 101. With such an arrangement of the commutator piece 101, the followability of the brush piece 103 to the movement of the commutator piece 101 is enhanced.

Japanese Patent Laid-Open No. 2005-6457 JP-A-6-86509

  However, when each commutator piece 101 is fixed to the surface of the sleeve 102 having a substantially circular outer peripheral surface, a slit portion 105 is formed between adjacent commutator pieces 101, but the slit portion 105 is a brush piece. When passing through 103, the brush piece 103 falls once on the slit portion 105 and then rides on the next commutator piece 101. In FIG. 10, the displacement of the brush piece 103 with respect to the rotation angle of the sleeve provided with the commutator 100 is shown. The horizontal axis represents the rotation angle, and the vertical axis represents the brush position. A rotation angle of −11 degrees to 11 degrees corresponds to the slit 105, and the direction of displacement of the brush piece suddenly reverses at an intermediate point (rotation angle 0 degree) of the slit 105. Due to the reversal of the displacement direction, there is a high possibility of chattering occurring in the slit portion 105. Furthermore, when an arc is generated by this chattering, the brush piece 103 and the commutator piece 101 are damaged, and the life of the motor is shortened. This chattering also causes radiation noise for peripheral devices.

  An object of the present invention is to provide a motor in which chattering is particularly reduced.

  A motor according to the present invention includes a rotor having a coil in which an electric wire is wound around an iron core fixed to a shaft, a sleeve fixed to the shaft, and a commutator piece main body having an arc-shaped cross section disposed on a circumferential surface of the sleeve A commutator having a plurality of commutator pieces with a brush, a brush piece made of a leaf spring extending in a tangential direction with respect to a reference circle with respect to the center of rotation, and a magnet arranged to surround the rotor The front end of the outer periphery of the commutator piece main body in the direction of rotation of the shaft is disposed on a reference circle with respect to the center of rotation, and is substantially behind the outer periphery of the downstream commutator piece main body. The end is disposed at a position where the brush piece comes into contact with the brush piece when the brush piece comes into contact with the front end of the outer periphery of the commutator piece main body on the upstream side.

  In this motor, the front end of the outer periphery of the commutator piece main body in the rotation direction of the shaft is located on a reference circle based on the rotation center, and the rear end of the outer periphery of the commutator piece main body in the rotation direction of the shaft is When the brush piece which consists of leaf | plate springs contact | abuts the front end of a commutator piece main-body part, it arrange | positions so that it may contact | abut to a brush piece. When the outer periphery of the commutator piece main body is curved with such a positional relationship, the radius of curvature of the outer peripheral surface of the commutator piece main body is from the front end to the rear end of the commutator piece main body with reference to the rotation center. It grows continuously. By adopting such a commutator piece main body part, when the brush piece passes between adjacent commutator piece main body parts, the brush piece does not fall between adjacent commutator piece main body parts smoothly. Since it rides on the next commutator piece main body part, chattering is made difficult to occur by avoiding sudden fluctuation of the brush piece in the direction of jumping up the brush pieces between adjacent commutator piece main body parts. As a result of reducing chattering, arcing is less likely to occur, brush pieces and commutator piece main bodies are less likely to be damaged, and a longer motor life can be achieved. Moreover, the cause of radiation noise for peripheral devices can be improved by reducing chattering.

  Further, it is preferable that the front end and the rear end of the commutator piece main body portion protrude from the peripheral surface of the sleeve. When the commutator piece main body is installed on the sleeve in this way, contact between the sleeve and the brush piece can be prevented, and the front end and rear end of the commutator piece main body can be reliably brought into contact with the brush piece. .

  Further, it is preferable that a plurality of commutator piece mounting surfaces that change so that the radius from the rotation center continuously decreases in the rotation direction are provided on the peripheral surface of the sleeve. By adopting such a commutator piece mounting surface, it is possible to use a commutator piece main body that is press-formed with a uniform plate material. And since press molding can be utilized for a commutator piece main-body part, reduction of manufacturing cost is attained.

  According to the present invention, by reducing chattering, it is possible to reduce the occurrence of arcs accompanying this chattering and damage to brushes and commutator pieces.

  Hereinafter, a preferred embodiment of a motor according to the present invention will be described in detail with reference to the drawings.

  As shown in FIGS. 1 to 3, the motor 1 is a cored motor and has a cylindrical metal housing 2, and a pair of brush pieces 20 (see FIG. 4) are provided at the rear end of the housing 2. An assembled resin bracket (not shown) is fixed. The motor 1 belongs to a small motor, and the housing 2 has a cylindrical shape with a diameter of 10 mm or less (for example, 3 to 6 mm) and a length of about 1 cm. A stator is provided in the small housing 2. 3 and the rotor 6 are accommodated.

  A stator (magnet) 3 made of a permanent magnet with N and S poles alternately magnetized is fixed to the inner wall surface 2 a of the housing 2, and three iron core grooves (slots) are formed inside the housing 2. A rotor 6 having a coil C around which an electric wire W is wound is accommodated in a pole 5a of the iron core 5 having the core. And the iron core 5 of the rotor 6 is configured by laminating a thin plate-like core 9 produced by punching a silicon steel plate having a thickness of about 0.2 to 0.5 mm in the axial direction of the shaft 7, It is also called a laminated core. Further, a shaft 7 is fixed to the center of the rotor 6, and the shaft 7 extends so as to penetrate the front end of the housing 2 and is supported by a pair of front and rear bearings (not shown). Yes.

  Further, a commutator 10 for reversing the current flowing in the coil C of the rotor 6 is fixed to the rear end of the shaft 7, and a pair of flat brush pieces 20 (see FIG. 4) are attached to the commutator 10. The coils C are in sliding contact with each other, and the coil C is appropriately fed by the cooperation of the brush pieces 20 and the commutator 10. Further, a weight (not shown) having a substantially semi-cylindrical shape is press-fitted into the tip of the shaft 7, and the housing 2 itself vibrates by rotating the weight at a high speed by the rotational force of the shaft 7. Such a weight is adopted when a casing of the device itself is vibrated by a portable small radio caller (for example, a mobile phone or the like).

  Further, the commutator 10 is fixed to the shaft 7 and has a resin sleeve 12 having a circular flange 12a, three commutator pieces 11 made by press molding of a copper thin plate, and a commutator piece. 11 includes a fixing ring 13 for fixing 11 to the sleeve 12. Further, each commutator piece 11 rises from the end of the commutator piece main body portion 14 and the commutator piece main body portion 14 having a circular arc cross section disposed along the surface of the cylindrical portion 12b of the sleeve 12 and circular. The riser part 15 protrudes from the outer peripheral surface 12c of the flange part 12a. And since the riser part 15 is accommodated in the riser accommodation recessed part 12d of the collar part 12a, the notch part 16 can be arrange | positioned adjacent to the outer peripheral surface 12c of the collar part 12a of the sleeve 12. FIG.

Further, the cut portion 16 provided in the riser portion 15 is formed in a J shape so that the wire W can be hooked well. And, by the cooperation of the circular outer peripheral surface 12c of the flange portion 12a and the J-shaped cut portion 16 of the commutator piece 11, the hooking accuracy of the wire W when the wire W is hooked on the cut portion 16 is improved, and the rectification is performed. Occurrence of solder failure when connecting the electric wire W to the child piece 11 by soldering H (see FIG. 1) is appropriately prevented.

  In such a commutator piece 11, as shown in FIGS. 4 and 5, the front end 14 a of the outer periphery of the commutator piece main body 14 has a rotation center P of the shaft 7 in the rotation direction S of the shaft 7. The rear end 14b of the outer periphery of the commutator piece main body 14 on the downstream side is arranged on the reference circle A (refer to the broken line), and the front end 14a of the outer periphery of the commutator piece main body 14 on the upstream side of the brush piece 20 It is arrange | positioned in the position contact | abutted to the brush piece 20 when it contact | abuts. In other words, the rear end 14b of the outer periphery of the downstream commutator piece main body 14 is a flat slidable contact surface 20a of the flat brush piece 20 that passes through the front end 14a of the outer periphery of the upstream commutator piece main body 14. Located on the top. In this case, the rear end of the outer periphery of the commutator piece main body 14 is not limited to the outermost end and may be in the vicinity of the sign 14b.

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In addition,

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In this case, each flat brush piece 20 is disposed on the commutator piece main body 14 so as to sandwich the sleeve 12 and is tangential to a reference circle A (see the broken line) based on the rotation center P. It consists of a leaf spring that extends.

  When the outer periphery of the commutator piece main body portion 14 is curved with such a positional relationship, the radius of curvature of the outer peripheral surface of the commutator piece main body portion 14 is determined from the front end of the commutator piece main body portion 14 with respect to the rotation center P. It continuously increases toward the rear end. Therefore, when the space between the adjacent commutator piece main body portions 14 and 14 passes through the brush piece 20, the brush piece 20 does not fall between the adjacent commutator piece main body portions 14 and 14, and smoothly follows. Since it rides on the commutator piece main body part 14, it is made difficult to generate chattering by avoiding sudden fluctuations of the brush piece 20 in the direction in which the brush piece 20 is flipped up between the adjacent commutator piece main body parts 14.

  In FIG. 6, the displacement of the brush piece 20 with respect to the rotation angle of the sleeve 12 provided with the commutator piece main body portion 14 is shown. The horizontal axis represents the rotation angle, and the vertical axis represents the brush position. A rotation angle of 11 degrees to 11 degrees corresponds to the space between the commutator piece main body portions 14 and 14, and the rear end 14b of the outer periphery of the commutator piece main body portion 14 abuts against the brush piece 20 at a rotation angle of 11 degrees. The brush piece 20 contacts the front end 14a and the rear end 14b of the outer periphery of the commutator piece main body 14 at a rotation angle of 11 degrees. When the rotation angle is 11 degrees or more, the displacement of the brush piece 20 gradually increases. That is, in the displacement of the brush piece 20, the displacement direction is not reversed, so that chattering is difficult to occur.

  As a result of reducing chattering, an arc is less likely to occur, the brush piece 20 and the commutator piece main body 14 are less likely to be damaged, and the life of the motor can be extended. Moreover, the cause of radiation noise for peripheral devices can be improved by reducing chattering.

  Further, as shown in FIGS. 5 and 7, three commutator piece mounting surfaces 22 are provided on the peripheral surface of the sleeve 12, and the commutator piece mounting surfaces 22 are formed as the bottom surface of the commutator piece housing recess 22 </ b> A. Has been. The commutator piece mounting surface 22 has a radius B from the rotation center P that continuously changes in the rotation direction S from the rear end 22b to the front end 22a and has a predetermined curvature, that is, in the rotation direction S. The radius B is continuously reduced from the rear end 22b to the front end 22a. Further, in order to prevent the resin sleeve 12 from being scraped by the brush piece 20 and preventing the generation of abrasion powder between the commutator piece main body portions 14, 14, the surface of the sleeve 12 is formed on the surface of the commutator piece main body portion 14. It is designed not to protrude from. Further, the commutator piece mounting surfaces 22 extend in the rotation axis direction and are arranged at equal intervals in the circumferential direction of the sleeve 12. The commutator piece mounting surface 22 having such a shape is suitable when the commutator piece main body portion 14 is formed of a plate material having a uniform thickness. The commutator piece mounting surface 22 having such a shape is most suitable for a pair of parallel two flat brush pieces 20.

  Therefore, by adopting the commutator piece mounting surface 22, the commutator piece main body portion 14 can be formed by pressing a plate material having a uniform thickness, and the commutator piece main body portion 14 is reliably positioned on the sleeve 12. Can do. And since a press can be utilized for shaping | molding of the commutator piece main-body part 14, manufacture cost can be reduced.

  Another embodiment is shown in FIG. The same members as those described so far are denoted by the same reference numerals, and redundant descriptions are omitted. Three commutator piece mounting surfaces 22 ′ are provided on the circumferential surface of the sleeve 12 ′. The commutator piece mounting surface 22 ′ has a predetermined curvature in which the radius B from the rotation center P continuously changes in the rotation direction S from the rear end 22b ′ to the front end 22a ′. In the direction S, the radius B is continuously reduced from the rear end 22b ′ to the front end 22a ′.

  Further, a step 25 is formed on the surface of the sleeve 12 'between the commutator piece main body portions 14 and 14, thereby preventing the resin sleeve 12' from being scraped by the brush piece 20 and preventing generation of wear powder. Therefore, the step portion 25 does not protrude from the commutator piece main body portion 14. Further, the commutator piece mounting surfaces 22 ′ extend in the rotation axis direction and are arranged at equal intervals in the circumferential direction of the sleeve 12 ′. The commutator piece mounting surface 22 ′ having such a shape is suitable when the commutator piece main body portion 14 is formed of a plate material having a uniform thickness. The commutator piece mounting surface 22 having such a shape is most suitable for a pair of parallel two flat brush pieces 20.

  Therefore, by employing the commutator piece mounting surface 22 ′, the commutator piece main body 14 can be formed by pressing a plate material having a uniform thickness. And since a press can be utilized for shaping | molding of the commutator piece main-body part 14, manufacture cost can be reduced.

It is sectional drawing which shows one Embodiment of the motor which concerns on this invention. It is a principal part expansion perspective view of the motor shown in FIG. It is a disassembled perspective view which shows a commutator. It is sectional drawing which shows the commutator applied to the motor which concerns on this invention. It is a principal part expanded sectional view of FIG. It is a graph which shows the displacement of the brush piece regarding the motor of this invention. It is a principal part expanded sectional view of a sleeve. It is sectional drawing which shows other embodiment of the motor which concerns on this invention. It is sectional drawing which shows the conventional commutator. It is a graph which shows the displacement of the brush piece regarding the conventional motor.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Motor, 3 ... Magnet, 5 ... Iron core, 6 ... Rotor, 7 ... Shaft, 11 ... Commutator piece, 12, 12 '... Sleeve, 14 ... Commutator piece main-body part, 14a ... Commutator piece main-body part Front end, 14b ... Rear end of commutator piece main body, 20 ... Brush piece, 22, 22 '... Commutator piece mounting surface, A ... Reference circle, B ... Radius of commutator piece mounting surface, C ... Coil, P ... Center of rotation, S ... direction of rotation.

Claims (3)

A rotor having a coil in which an electric wire is wound around an iron core fixed to a shaft, a sleeve fixed to the shaft, and a plurality of commutator piece main bodies having an arc-shaped cross section disposed on a peripheral surface of the sleeve A commutator having a commutator piece, a brush piece made of a leaf spring extending in a tangential direction with respect to a reference circle with respect to the rotation center, and a magnet arranged to surround the rotor. In the motor
In the rotational direction of the shaft, the front end of the outer periphery of the commutator piece main body is disposed on the reference circle with respect to the rotation center, and the substantially rear end of the outer periphery of the commutator piece main body on the downstream side is The motor is disposed at a position where the brush piece comes into contact with the brush piece when the brush piece comes into contact with the front end of the outer periphery of the commutator piece main body on the upstream side.   The motor according to claim 1, wherein the front end and the rear end of the commutator piece main body protrude from a peripheral surface of the sleeve.   3. A plurality of commutator piece mounting surfaces that change so that a radius from the center of rotation continuously decreases in a rotation direction are provided on a peripheral surface of the sleeve. motor.

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