Minebea Company, Limited

Hiroyuki Furusaki

Yuzuru Suzuki

Takayuki Yamawaki

Manabu Nakamura

Masaki Kagawa

A brushless motor includes: a stator assembly including a stator core which includes a plurality of pole teeth each having a winding therearound; and a rotor assembly including a magnet which has a ring shape, is rotatably disposed so as to oppose the pole teeth of the stator core and which is circumferentially magnetized with a plurality of magnetic poles with opposite polarities alternating with each other, wherein the number of the pole teeth of the stator core is twice the number of the magnetic poles of the magnet such that each magnetic pole opposes a pair of adjacent pole teeth, one pair of adjacent windings have the same number of winding turns and the same winding direction as each other, and wherein another pair of windings located next to the one pair of windings have a winding direction opposite to the winding direction of the one pair of windings.

Brushless motor having a reduced axial dimension

A vibrating motor has a shaft, a stator including a yoke having pole teeth extending toward an axis of the shaft from an inner circumference and coils wound around the pole teeth, a rotor including an eccentric weight formed on a radially outer surface of the shaft, and a permanent magnet integrally formed with the eccentric weight, and a bearing device rotatably supporting the rotor maintaining clearance between the inner circumference of the pole teeth and the rotor. The rotor has a structure in which the shaft, the eccentric weight, and the permanent magnet are integrally formed with each other by a thermoplastic magnetic material composing the permanent magnet.

Production method of vibrating motor and rotor for vibrating motor

A PM stepping motor includes: a stator assembly composed of two stator units which are axially coupled to each other with a molding resin material, and each of which includes: inner and outer yokes each having a plurality of pole teeth; a bobbin including inner and outer flanges; and a coil wound around the bobbin, thus providing two such inner yokes, outer yokes, bobbins and coils in total; a rotor assembly which includes a shaft and a magnet, and which is rotatably disposed in the hollow of the stator assembly; and two bearings to rotatably support the shaft of the rotor assembly, wherein the two bobbins are formed of the molding resin material to be consolidated with the two inner yokes, and wherein a plurality of protrusions are formed of the molding resin material to extend integrally from the outer flange of each of the two bobbins.

PM stepping motor having a stator assembly

In a small diameter stepping motor including two stator units each including a bobbin formed of an insulating material, each bobbin includes: a circular hollow cylinder portion having a winding; two flanges disposed respectively at the both ends of the cylinder portion; and a terminal structure disposed at one of the two flanges and including two terminal blocks and a pair of electrical contact members at which the lead-out lines of the winding are terminated, wherein the two terminal blocks are circumferentially shifted in position from each other with respect to the cylinder portion axis extend axially outwardly, and the terminal blocks of one bobbin intermesh with the terminal blocks of the other bobbin such that the terminal blocks of the one bobbin overhang a part of the winding wound on the other bobbin and vice versa when the two stator units are coupled to each other.

Small diameter stepping motor, bobbin used therein and manufacturing method thereof

An actuator includes: a rotary shaft allowed to axially and including a threaded portion at a protruding portion thereof and two idle regions disposed respectively at both ends of the threaded portion; a movable structure adapted to travel along the rotary shaft; a stopper means facing the end of the protruding portion of the rotary shaft and configured to restrict the axial movement of the movable structure located at the idle region; an open space disposed between the stopper means and the end of the rotary shaft and configured to allow the rotary shaft to axially move; an urging means for urging the movable structure toward the motor; and a recovery means for urging the movable structure toward the threaded portion by a magnetic thrust force exerted by cutting off power supply to the motor when the movable structure is in contact with the stopper means.

Actuator for lens driving mechanism

A stepping motor includes: a stator which includes a cup-like first (outer) yoke having a plurality of notches formed at its bottom plate, a second (inner) yoke, and a bobbin having a coil wound therearound and housed in the annular hollow space formed by the first and second yokes; and a pair of bearings each of which includes a hollow-cylindrical main body and a flange structure having a plurality of protrusions, and is attached to the stator such that the protrusions engage with the notches of the first yoke thereby preventing the bearing from rotating relative to the first yoke, and such that the protrusions make contact with a flange of the bobbin thereby precisely positioning the bearing relative to the first yoke with respect to the axial direction, which prohibits any portions of the bearing from protruding axially outwardly beyond the bottom plate of the first yoke.

Stepping motor

A rotor includes: a magnet having a circular cylinder shape and having a hole formed through its axial center, wherein the hole has in axial cross section a regular polygonal shape having flat portions and angle portions, and wherein a recess having a truncated cone shape is disposed at an axial end of the magnet such that the recess has its maximum diameter portion located at the axial end and has its minimum diameter portion communicating with the hole; and a shaft fitted in the hole of the magnet, wherein the outer circumference of the shaft makes contact with the flat portions of the hole of the magnet thereby forming a plurality of gaps between the outer circumference of the shaft and the angle portions of the hole of the magnet, and adhesive is filled in the gaps.

Rotor structure

In a stepping motor including two stators and a rotor having two magnets, three dimensional relations, specifically a relation of Lm/Ls, another relation of d/2Lm, and still another relation d/D, are optimally determined while satisfying their respective ranges: 0.35&#x2266;Lm/Ls&#x2266;0.45; 0.77&#x2266;d/2Lm&#x2266;1.10; and d/D&#x2266;0.45, where Lm is the axial dimension of the magnet, Ls is the axial dimension of the stator, d is the outer diameter of the magnet, and D is the outer diameter of the stator, whereby a space for accommodating a sufficient number of coil turns is secured maximally in the stator, and the inertia and the cogging torque of the rotor are reduced maximally, which leads to producing the highest possible torque at a high rotation speed range required.

Growing community of inventors

Kitasaku-gun, Japan

Hiroyuki Furusaki