Patents Assigned to Mabuchi Motor Co. Ltd.
  • Patent number: 8188699
    Abstract: The rotation period of a motor is subdivided by edge interval times and a rate of change between a currently calculated edge interval time and an edge interval time calculated one rotation of the motor previously is calculated at the detection of each edge. Then the rotation period of the motor is calculated by multiplying a set reference period by the calculated rate of change.
    Type: Grant
    Filed: December 18, 2008
    Date of Patent: May 29, 2012
    Assignee: Mabuchi Motor Co. Ltd.
    Inventors: Toru Tategami, Shumpei Fujii
  • Publication number: 20120068566
    Abstract: A DC motor comprises: a tubular metal case; a magnet that is provided along the inner surface of the metal case and has four or more of magnet poles in the circumferential direction; an armature that is arranged to face the magnet and composed of a core and a coil; and a shaft. The magnet is formed of a material with a maximum energy product BHmax of 3 to 6 MGOe. When the thickness of the magnet in the radial direction of the armature is indicated by T [mm] and the outer diameter of the core is indicated by d [mm], the ratio T/d of the thickness T of the magnet to the outer diameter d of the core is 0.16 or more.
    Type: Application
    Filed: September 16, 2011
    Publication date: March 22, 2012
    Applicant: MABUCHI MOTOR CO., LTD.
    Inventor: Yusuke MIYAJIMA
  • Patent number: 8110956
    Abstract: The side wall of a motor casing is formed into a quadrangular shape such that four flat side portions, and arcuate corner portions located at respective corners are continuously joined together. A field magnet having a quadrangular external shape is formed such that four flat side portions, and four arcuate corner portions located at respective corners are continuously joined together. The arcuate corner portions of the motor casing and the arcuate corner portions of the field magnet extend along respective circles having a center located at the center of a motor shaft, and the central angles of the arcuate corner portions fall within a range of 15° to 35° inclusive. The field magnet is press-fitted or bonded into the motor casing such that the corner portions of the field magnet come into close contact with the corner portions of the motor casing.
    Type: Grant
    Filed: April 11, 2008
    Date of Patent: February 7, 2012
    Assignee: Mabuchi Motor Co., Ltd.
    Inventors: Eiji Uenishi, Nobuyuki Nemoto
  • Publication number: 20110192087
    Abstract: A magnetic path is formed, in response to the rotation of a motor, by a magnetic detector (24 or 26) (more exactly, a magnetic wire (70)), a magnetic pole of the magnet (22), which is placed counter to each magnetic detector, and the rotating shaft (20). The magnetic wire (70) is formed of a magnetic material capable of causing a large Barkhausen jump. Whenever the magnetic pole opposite each magnetic element changes in response to the rotation of the motor, the direction of magnetic field constituting the magnetic path changes precipitously and a pulse signal in response to the change is outputted from the magnetic detector. Since the direction of magnetization of the magnetic wire (70) changes with a change in magnetic flux density received from a magnet (22), an induced electromotive force occurs due to a change in magnetic flux received by a detection coil. This makes enables the magnetic detector to output pulse signals without power supply.
    Type: Application
    Filed: October 31, 2008
    Publication date: August 11, 2011
    Applicant: MABUCHI MOTOR CO. LTD.
    Inventor: Toru Tategami
  • Patent number: 7994682
    Abstract: Each of the paired brush devices includes a brush in sliding contact with a commutator, a brush arm holding the brush, and a brush base to which the brush arm is fixed and which has a base hole. The pair of brush devices are disposed such that a line connecting the centers of the pair of brushes inclines in relation to a line connecting the centers of a pair of magnets. Each of the brush arms of the brush devices is disposed on the outside of the corresponding brush base at a location where the brush arm is fixed to the brush base, and one of the brush arms is bent from the outside of the corresponding brush base toward the inside thereof while being passed through the base hole to intersect the brush base.
    Type: Grant
    Filed: January 18, 2008
    Date of Patent: August 9, 2011
    Assignee: Mabuchi Motor Co., Ltd.
    Inventors: Ryoichi Kimura, Yukio Takahashi
  • Patent number: 7990010
    Abstract: A side wall of a motor casing is formed into a polygonal shape such that flat side portions and corner portions located at respective corners between the side portions are continuously joined together. A field magnet, which has an outer circumferential shape approximately coinciding with the inner circumferential shape of the motor casing, has magnet side portions and magnet corner portions, and has a rib provided on outer circumferential surfaces of the magnet side portions. The magnet is disposed, through press-fitting, within the motor casing such that at least the rib comes into contact with the inner circumferential surface of the motor casing, wherein the magnet side portions, excluding the rib, are formed such that small clearances are formed between the magnet side portions and the side portions of the motor casing.
    Type: Grant
    Filed: April 11, 2008
    Date of Patent: August 2, 2011
    Assignee: Mabuchi Motor Co., Ltd.
    Inventors: Nobuyuki Nemoto, Hiroshi Yamazaki
  • Patent number: 7973529
    Abstract: A sensor magnet holder is mounted on a motor shaft, and a sensor magnet is provided relative to a magnetic induction sensor on the non-moving side for obtaining a signal indicative of a rotational position of the motor shaft. The sensor magnet holder integrally forms a cylindrical portion, a flange portion of a terminal end of the cylindrical portion having a large diameter, a magnet rear end holding portion of the other terminal end of the cylindrical portion and a plurality of snap fit board portions. A shaft press fit portion is formed on an internal diameter of the flange portion. The plural snap fit board portions extend from the cylindrical portion in an axial direction of the motor shaft. A magnet front end holding portion is formed at an extending tip over an outer diameter surface of each of the snap fit board portions.
    Type: Grant
    Filed: June 30, 2009
    Date of Patent: July 5, 2011
    Assignee: Mabuchi Motor Co., Ltd.
    Inventors: Satoshi Kikuchi, Takahiro Akimoto
  • Patent number: 7954226
    Abstract: In the present invention, driving torque outputted from a motor portion is transmitted to a worm from a motor shaft, further to a helical gear from the worm, and is taken out to the outside from an output shaft which rotates together with the helical gear with a fixed shaft fixed to a gear box as a center. This fixed shaft is constructed in a hollow and cylindrical shape having an opening in which one end portion thereof has been opened, and a ceiling surface in which the other end portion thereof has been closed, and one end portion of this fixed shaft is subjected to dislocation preventive work, and is fixed to a gear box made of resin by pressing-in or insert molding. The other end portion of the fixed shaft is formed with the dislocation preventive structure of the output shaft and the helical gear installed to the fixed shaft.
    Type: Grant
    Filed: July 24, 2008
    Date of Patent: June 7, 2011
    Assignee: Mabuchi Motor Co., Ltd.
    Inventors: Takeshi Okumura, Kazuyuki Yamamoto, Shinichi Taniguchi
  • Patent number: 7952241
    Abstract: A cooling fan includes a fan ring to be attached to an end surface of a rotor core near the outer circumference thereof, and a plurality of fins connected to the fan ring. The fan ring has positioning leg portions provided on an end surface thereof facing a thrust direction. The fan ring is positioned in relation to the rotor core through insertion of the positioning leg portions into core slots of the rotor core. The fan ring has wire accommodation recesses which are formed on the end surface of the fan ring facing the thrust direction and communicate with the core slots.
    Type: Grant
    Filed: December 1, 2008
    Date of Patent: May 31, 2011
    Assignee: Mabuchi Motor Co., Ltd.
    Inventors: Masahiko Kato, Yusuke Miyajima
  • Patent number: 7884510
    Abstract: The present invention is used with a stopper mechanism for mechanically stopping the rotation of a motor. A pair of brushes is disposed such that a line which passes through the center of a rotor and connects the centers of the paired brushes is offset by a predetermined angle from a line which connects the centers of paired magnets. A commutator is disposed in such a manner as to be offset from a reference position by the same angle as the predetermined angle by which the paired brushes are offset. The predetermined angle falls within a range between an angle obtained by dividing 70° by the number of pairs of stator poles and an angle obtained by dividing 290° by the number of pairs of stator poles. Specifically, in the case of two stator poles, the predetermined angle falls within a range of 70° to 290° inclusive. In the case of four stator poles, the predetermined angle falls within a range of 35° to 145° inclusive.
    Type: Grant
    Filed: December 21, 2007
    Date of Patent: February 8, 2011
    Assignee: Mabuchi Motor Co. Ltd.
    Inventors: Hiroshi Yamazaki, Hiroyuki Masutani, Masafumi Momma, Junichi Harano
  • Publication number: 20110018380
    Abstract: A DC motor 10 includes: a housing 12 having a polygonal cross section; a magnet 20 provided along the inner circumference of the housing 12 and having magnetic poles at the corners of the housing 12; a shaft 22 configured to be inserted into the housing 12 along the axial line of the housing 12; an armature 24 secured to the shaft 22 and provided to face the magnet 20; a commutator 26 fitted to the shaft 22 so as to be coaxial with the armature 24; a columnar carbon brush 30 provided in alignment with the radial direction of the commutator 26 such the end surface of the brush is in sliding contact with the outer circumference of the commutator 26; and a biasing member provided in the housing 12 and configured to bias the carbon brush 30 toward the commutator 26. The carbon brush 30 is provided at a position along the circumference of the housing 12 where the maximum length of the carbon brush 30 is ensured.
    Type: Application
    Filed: January 22, 2009
    Publication date: January 27, 2011
    Applicant: MABUCHI MOTOR CO. LTD.
    Inventors: Taro Yoshida, Takayuki Kodama
  • Patent number: 7876017
    Abstract: An object of the present invention is to provide a commutator or brush material for a small electric DC motor which enables a lengthened operating life of a spindle motor for a DVD controlled using a pulse current. A commutator material for a small electric DC motor in accordance with the present invention is characterized by being composed of 6.0 to 10.0 wt % of Cu, 1.0 to 5.0 wt % of ZnO, and a balance of Ag and in that Cu metal particles and ZnO particles are dispersed in an AgCu matrix. A brush material for a small electric DC motor in accordance with the present invention is characterized by being composed of 0.1 to 5.0 wt % of MgO and a balance of Ag and in that MgO particles are dispersed in an Ag matrix, or is characterized by being composed of 5.0 to 15.0 wt % of Ni and a balance of Pt and in that Ni is dissolved in a Pt matrix.
    Type: Grant
    Filed: May 10, 2006
    Date of Patent: January 25, 2011
    Assignees: Mabuchi Motor Co., Ltd., Tanaka Kikinzoku Kogyo K.K.
    Inventors: Keiji Nakamura, Makoto Takabatake, Masahiro Takahashi, Shuichi Kubota, Takao Asada, Toshiya Yamamoto
  • Publication number: 20110006628
    Abstract: The present invention enables firm fixation between a motor casing and a casing lid at low cost through employment of a simple structure without need to use adhesive. A casing lid made of resin is fixedly fitted to an opening portion of a motor casing made of metal. Grooves or depressions are provided at the bottoms of a plurality of fixation portions provided on the casing lid at constant intervals in the circumference direction thereof. Bend portions at the opening portion of the motor casing are caused to bite into the grooves or depressions of the casing lid fitted into the opening portion of the motor casing, whereby the motor casing and the casing lid are fixed together.
    Type: Application
    Filed: January 6, 2009
    Publication date: January 13, 2011
    Applicant: MABUCHI MOTOR CO., LTD.
    Inventors: Hisashi Ogino, Mitsushi Kinoshita
  • Publication number: 20100320854
    Abstract: A motor includes a tubular housing having flat side walls along each side of rectangular joined with each other by joining sections, a magnet, having magnet poles in the jointing section, disposed along the inner peripheral surfaces of the housing, a shaft inserted along the axis of the housing, an armature fixed to the shaft in such a position as to be opposite to the magnet, a commutator mounted on the shaft, a carbon brush in sliding contact with the outer peripheral surface of the commutator, and electrical components provided within the housing. The electrical components in the longer direction are arranged nonparallely with all the sides of the housing.
    Type: Application
    Filed: May 12, 2010
    Publication date: December 23, 2010
    Applicant: MABUCHI MOTOR CO. LTD.
    Inventors: Hiroshi Yamazaki, Eiji Mayumi
  • Patent number: 7732963
    Abstract: A small-sized motor includes a field magnet attached to an inner circumferential surface of a metallic motor casing and having four or more magnetic poles. The field magnet is formed of a single ring-shaped magnet member having a predetermined thickness with respect to the radial direction and a predetermined length with respect to the thrust direction. At each of portions between the magnetic poles formed through magnetization, the magnet member has a thin portion having a reduced thickness with respect to the radial direction, the thin portion being formed by cutting the magnet member from the radially outward side. The magnetization is performed in the radial direction so as to alternately form S poles and N poles in the circumferential direction. At each of portions between the magnetic poles, the magnet member may have cut portions formed at opposite end portions of the magnet member with respect to the thrust direction.
    Type: Grant
    Filed: August 3, 2007
    Date of Patent: June 8, 2010
    Assignee: Mabuchi Motor Co., Ltd.
    Inventors: Satoshi Iizuka, Mitsushi Kinoshita
  • Patent number: 7663276
    Abstract: A photo sensor module includes a holder made of resin and a light-emitting element and a light-receiving element accommodated in the holder. A printed circuit board is fixed to a flat side wall portion of a motor. The resin holder has a guide portion which is formed integrally therewith and which comes into contact with an end surface and a bearing-holding portion of an end bell. The printed circuit board is fixed in a state in which the guide portion is sandwiched between the bearing-holding portion and the printed circuit board while being brought into contact with the end surface of the end bell, whereby the photo sensor module is positioned in thrust and radial directions of the motor.
    Type: Grant
    Filed: February 12, 2008
    Date of Patent: February 16, 2010
    Assignee: Mabuchi Motor Co., Ltd.
    Inventor: Kouhei Igarashi
  • Patent number: 7663277
    Abstract: An inner-rotor-type brushless motor includes a bus bar which connects together U-phase, V-phase, and W-phase windings and connects them to output wires. The bus bar includes, as conductive members, three external terminals connected to first ends of the windings and one Y-connection terminal for connecting second ends of the windings together. The external terminals and the Y-connection terminal are disposed on the body of the bus bar such that the Y-connection terminal and the external terminals are located on one side on the circumference of the bus bar body, whereby the bus bar body has a circumferential region where the conductive members are not present. A sensor bard carrying a position detection sensor is attached the bus bar body such that the position detection sensor is located in the circumferential region where the conductive members are not present.
    Type: Grant
    Filed: July 21, 2008
    Date of Patent: February 16, 2010
    Assignee: Mabuchi Motor Co., Ltd.
    Inventors: Nobuo Kinoshita, Yuichiro Matsuoka
  • Patent number: 7652402
    Abstract: A plurality of coils wound around a stator magnetic-pole core are connected together and connected to output wires by use of a bus bar. The bus bar having a generally cylindrical body portion is disposed at one axial end of the stator magnetic-pole core, around which the coils are wound such that clearances are formed within magnetic-pole core slots, with an axial clearance formed between the bus bar and the coils. The body portion has such a radial dimension that at least a portion of the clearances within the magnetic-pole core slots is left uncovered. Air holes are formed in the motor housing on opposite sides of the stator magnetic-pole core to thereby form cooling air passages extending through the magnetic-pole core slots.
    Type: Grant
    Filed: May 22, 2007
    Date of Patent: January 26, 2010
    Assignee: Mabuchi Motor Co., Ltd.
    Inventors: Nobuo Kinoshita, Yuichiro Matsuoka
  • Publication number: 20100001719
    Abstract: A sensor magnet holder is mounted on a motor shaft, and a sensor magnet is provided relative to a magnetic induction sensor on the non-moving side for obtaining a signal indicative of a rotational position of the motor shaft. The sensor magnet holder integrally forms a cylindrical portion, a flange portion of a terminal end of the cylindrical portion having a large diameter, a magnet rear end holding portion of the other terminal end of the cylindrical portion and a plurality of snap fit board portions. A shaft press fit portion is formed on an internal diameter of the flange portion. The plural snap fit board portions extend from the cylindrical portion in an axial direction of the motor shaft. A magnet front end holding portion is formed at an extending tip over an outer diameter surface of each of the snap fit board portions.
    Type: Application
    Filed: June 30, 2009
    Publication date: January 7, 2010
    Applicant: MABUCHI MOTOR CO., LTD.
    Inventors: Satoshi Kikuchi, Takahiro Akimoto
  • Patent number: 7640827
    Abstract: Driving torque outputted from a motor portion is transmitted to a worm from a motor shaft, further to a helical gear from the worm, and is taken out to the outside from an output shaft which rotates together with the helical gear with a fixed shaft fixed to a gear box as a center. This fixed shaft is constructed in a hollow and cylindrical shape having an opening in which one end portion thereof has been opened, and a ceiling surface in which the other end portion thereof has been closed, and one end portion of this fixed shaft is subjected to dislocation preventive work, and is fixed to a gear box made of resin by pressing-in or insert molding. The other end portion of the fixed shaft is formed with the dislocation preventive structure of the output shaft and the helical gear installed to the fixed shaft.
    Type: Grant
    Filed: November 8, 2004
    Date of Patent: January 5, 2010
    Assignee: Mabuchi Motor Co., Ltd.
    Inventors: Takeshi Okumura, Kazuyuki Yamamoto, Shinichi Taniguchi