Mitsumi Electric Company Ltd.

Akira Shibata

Yoshihito Otomo

Koichi Seno

Takashi Watanabe

Hisateru Komatsu

Makoto Konno

Makoto Takahashi

Hisashi Shibata

Masashi Sato

Hiroshi Sampei

Mitsutoshi Ohizumi

Kenji Katoh

Kouichi Hosoya

In an index signal generator for generating an index signal for use in a direct-drive motor having a rotation axis and comprising a stator and a rotor, a particular at least one of M magnetized elements is used as an index detection magnet having magnetic force which is different from those in remaining ones of the M magnetized elements. Wound around one of a specific one of particular three cores in the stator, an index detection coil detects variations of the magnetic force generated by the ring-shaped permanent magnet to produce a detected signal. On the basis of the detected signal, the index signal is generated.

Method of generating an index signal with reduced parts

In a flexible disk drive having a main frame in which a flexible disk is inserted and a direct-drive motor having a stator disposed on a main surface of the main frame and a rotor including a permanent magnet, a gap between the main surface of the main frame and the permanent magnet is set at a distance so that the rotor does not fall due to gravity by attracting the rotor to the main frame by the magnetic attractive force of the permanent magnet even if the rotor is turned upside down to the stator.

Flexible disk drive with a gap between a main frame and a permanent magnet of a rotor so that the rotor does not fall although the rotor is upended to a stator

A male connector is connected to a female connector which includes a plurality of terminal hole pairs, each having a signal terminal hole and an earth terminal hole which are arranged in a first direction. The plurality of terminal hole pairs are arranged on the female connector body in a second direction perpendicular to the first direction. The male connector includes a male connector body, a plurality of signal terminal pins and a plurality of earth terminal pins. The signal terminal pins are provided on the male connector body, and are accommodated in the signal terminal holes respectively. The plurality of earth terminal pins are provided on the male connector body, and are accommodated in the earth terminal holes. The earth terminal pins are smaller in number than the earth terminal holes of the female connector.

Male connector terminal

A motor rotatably driving a flexible disk has a rotor having an external peripheral side surface on which an index detection magnet is mounted. A main circuit board mounts a control circuit for carrying out a driving control of the motor and extends in a direction perpendicular to a rotation axis of the motor. Attached to the main circuit board, a sub circuit board extends in a direction in parallel with the rotation axis of the motor at a position close to the external peripheral side surface of the rotor. Mounted on the sub circuit board, an index detection Hall element has a magnetic field detection surface which is disposed so as to oppose to the external peripheral side surface of the rotor.

Flexible disk drive comprising an index detection hall element having an improved detection sensitive condition of a magnetic field

The index signal generator generates an original signal every the rotor of the direct-drive motor rotates, and delays the original signal by a delay time to produce index signal. The index signal generator comprises, as the delay giving the delay time, the delay counter that can be set the initial value, instead of an analog delay circuit, a variable register and a capacitor. The delay counter comprises the counter and the counter value selector for determining the initial value of the counter. The counter starts to count the clock signals generated by the clock in response to the original signal, and stops counting the clock signals and generates the index signal when the number of the clock signals counted by the counter reaches the initial value.

Index signal generator

In a photointerrupter comprising a light emitting diode and a photo transistor which are opposed to each other, the photo transistor has an emitter which is grounded through a resistor while the light emitting diode has a cathode which is connected to an input terminal of a one IC chip for controlling a flexible disk drive. The one IC chip incorporates a constant current source which is connected to the input terminal through an npn-type bipolar transistor. The one IC chip incorporates a logic circuit having an output terminal which is connected to a base of the npn-type bipolar transistor.

Photointerrupter driving circuit capable of decreasing the number of

In an integrated circuit for use in controlling a flexible disk drive for driving a flexible disk loaded therein, a power on reset circuit produces a reset signal after a predetermined time duration elapses where a power supply voltage is stable from a time when a power supply is applied. The power on reset circuit comprises a voltage detecting circuit for detecting a power supply voltage to produce a voltage detected signal and a delay circuit for producing, responsive to the voltage detected signal, the reset signal after the predetermined time duration elapses. Disposed between a selectable function circuit and a logic circuit, an output holding circuit holds output signals of the selectable function circuit as held signals and supplies the held signals to the logic circuit. The output holding circuit consists of two D-type flip-flops which are disposed in correspondence with two output signal lines of a logical circuit.

Integrated circuit for a flexible disk drive capable of always

A sub-printed board 40 is disposed on a main plate of a main frame 30 at a position close to a front bezel 37. A main printed board 31 is provided on the main plate at a position opposite to the front bezel. A rotation drive mechanism for magnetic disks is mounted on the sub-printed board. A loading mechanism is assembled over the rotation drive mechanism in order to mount and eject the magnetic disks on and out of the magnetic disk drive. A head carriage 34 is disposed above the main printed board by means of a first supporting member provided on the main plate.

Magnetic disk drive of a structure capable of being lightened in weight

A head feeding mechanism in a magnetic recording and reproducing device comprises: a '0' side carriage which has a '0' side magnetic head mounted on the surface of the front end portion thereof, and is fed in the direction of length of a slot formed in a magnetic disk holder, into which a magnetic disk is loaded, by a guide provided on a device frame; and a '1' side carriage which has a '1' side magnetic head 16 mounted on the surface thereof which is confronted with the '0' side magnetic head, and a base which is flexibly supported on the base 1a of the '0' side carriage, and driven ears extended from the middle portion thereof which are driven by the edge of the slot with the aid of an energizing spring. In the mechanism, the '0' side carriage is formed rigid by molding resin, and has a flexible thin portion in the middle of the front end portion thereof which is much smaller in thickness than the other portions, and the '0' side magnetic head is soldered to a flexible printed circuit board with the flexible thin portion held between the '0' side magnetic head and the flexible printed circuit board.

Head feeding mechanism in magnetic recording and reproducing device

An improved disc drive is capable of compensating the relative positional shift of a head caused mainly by a temperature change. The disc drive includes a frame having a disc holder for rotatably driving a disc, a head for reading information recorded in the disc, a head carriage which is movable in a predetermined radial direction of the disc, a rotation shaft extending in parallel with the radial direction, a driving mechanism for moving the head carriage in the radial direction by engaging with the rotation shaft, an adjustment mechanism for compensating the positional shift of the head due to a change of ambient temperature by providing an additional deformation of the adjustment mechanism to the carriage.

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Murayama, Japan

Akira Shibata