Kabushiki Kaisha Sankyo Seiki Seisakusho

Sankyo Seiki Mfg. Co., Ltd

Shinji Kinoshita

Mitsuru Ide

Yutaka Ishizuka

Koichi Katakura

Akihiro Nagata

Toru Kumagai

Shinji Ohta

Shinji Ota

Hiromitsu Gotoh

Yoshitaka Murayama

A motor rotor 10 is formed as follows: First, in a first forging step, a hum manufacturing primary block 6A is formed. Next, a second forging step B is effected to form the primary blank 6A into a secondary blank 6B. In this step, a forging die is used to secure an annular yoke 34 to the inner cylindrical surface 61a of a hub cylindrical portion 61 by punching, in such a manner that both whole edges of the annular yoke are sealingly closed thereby. In the second forging step B, by drawing the inner cylindrical surface 34a of the annular yoke, its circularity is improved. The annular yoke can be secured to the hub cylindrical portion with use of an adhesive agent. Moreover, the annular yoke can be fixed in such a manner that it is accurately coaxial with the hub cylindrical portion. In addition, the gap between the annular yoke and the hub cylindrical portion can be eliminated.

Disk drive motor, and method of manufacturing its rotor

A spindle motor has a fixed member of a motor, a rotor rotatably supported with respect to the fixed member, a shaft provided on either the fixed member or the rotor, a first ball bearing fitted on a head side of the shaft and a second ball bearing fitted on a base side of the shaft and having an axial dimension larger than an axial dimension of the first ball bearing. A circumferential wall, preferably on the fixed member, has a small gap with an outer circumferential wall of an outer ring of the second ball bearing.

Spindle motor

A spindle motor comprises a motor shaft, which is rotatably supported by a motor frame via a bearing and a hub, which is formed integral with the motor shaft for securing a data disk. The hub is made of a powder metallurgical product and is bonded with the motor shaft by sintering.

Spindle motor and method of manufacturing the same

A magnetic disk driving device includes a frame which supports a shaft, a hub adapted to hold a disk, and upper and lower bearings which are fitted in a bearing holding hole and rotatably support the hub. The frame includes a cylindrical protrusion which is confronted through a small gap d with the outer cylindrical surface of the outer race of the lower bearing. The small gap d forms a labyrinth in the space through which the inside of the lower bearing is communicated with the outside. The inner cylindrical surface of an annular protrusion formed on the bottom of the hub, and the inner cylindrical surface of the cylindrical protrusion are substantially equal in diameter.

Disk driving motor

A current feed means is connected to an armature coil of a motor. Current is fed from the current feed means to the armature coil while the frequency of the current is gradually varied from a preset frequency to another preset frequency, thereby to vibrate the motor. The amplitudes of the frequencies are measured by a frequency analyzer means, which is brought into contact with the motor. The frequency at which the amplitude of the vibration of the motor is peaked indicates the natural frequency of the motor.

Method of measuring natural frequency of motor

A magnetic disc drive device includes a labyrinth structure proximate to the ball bearings to effectively prevent scattering of particles. The labyrinth structures are formed by various arrangements where complicated passages are defined by elements arranged proximate to the inner ring and the outer ring of a ball bearing. One of the elements forming the passages being either the hub or the frame of the magnetic disc drive device.

Magnetic disc drive device

A disk drive motor having a center shaft, a pair of ball bearings inner rings thereof being fixedly fitted with the center shaft while interposing a predetermined distance therebetween, a hub being supported so as to be rotatable about the center shaft while having outer rings of the ball bearings fixed to an inner hole thereof, a drive magnet integrally rotating the hub, a stator core being arranged so as to confront the drive magnet, and a first seal means and a second seal means being respectively arranged along ways to a space outside the motor to constitute seal mechanisms while communicating the respective ball bearings with the space outside the motor, wherein an annular spacer is fixedly fitted with the center shaft between the inner rings of the pair of ball bearings and an outer circumferential surface of the spacer confronts an inner circumferential surface of the inner hole of the hub while interposing a small gap therebetween, so that a labyrinth seal mechanism is formed.

Disk drive motor with labyrinth seal

A disk driving device comprises a hub on which a data recording disk is mounted. The hub is rotated together with the disk. The hub has a disk mounting surface on which the disk is mounted. The disk mounting surface is inclined radially outwardly of the axis of rotation of the hub towards the side of the hub where the disk is mounted.

Growing community of inventors

Nagano, Japan

Shinji Kinoshita