Thk Co., Ltd.

Sony Corporation

Ryuji Takeda

Tetsuhiro Shiomi

Shigeru Ebina

Seiichiro Oishi

Takeki Shirai

Tetsuhiro Nishide

Hiroshi Niwa

Mitsuaki Honma

Hidekazu Michioka

Yasushi Saito

Takahiro Komazaki

Mitsuhiko Awata

A disk drive apparatus for recording (writing) and/or reproducing (reading) information on an optical disk by rotating the optical disk, and adjusting the tilt angle of an optical pickup device with respect to the optical disk. A spindle chassis rotationally supports a turntable on which the optical disk is placed. A pickup chassis, rotationally supported on said spindle chassis, movably supports an optical pickup device that writes and/or reads the information to/from the optical disk and is movable toward and away from the turntable. A tilt mechanism adjusts the tilt angle of the optical pickup device with respect to the optical disk by rotating the pickup chassis with respect to the spindle chassis.

Apparatus and method for adjusting the tilt angle of an optical pickup device

The object of the present invention is to propose an optical disk driving apparatus, an optical disk driving method and an optical disk apparatus capable of reducing the occurrence of disturbance to focus servo control and tracking servo control. In the optical disk driving apparatus, a tilt driving section ( ) is provided with waveform shaping unit for shaping a driving current waveform driving a tilt motor ( ) for changing the angle of an optical pickup ( ) with respect to the rotating surface of an optical disk. Thus, it is possible to prevent the vibration of the optical pickup ( ), to reduce disturbance derived from the vibration of an objective lens ( ) to focus control and tracking control and to suppress mechanical noise while tilt driving is being performed. Besides, since there is no need to provide a tilt sensor, the optical pickup ( ) can be made small in size and therefore, the smaller-sized optical disk driving apparatus can be provided.

Optical disk driving apparatus, optical disk driving method and optical disk apparatus

Lubricant retaining slits ( ) are formed on a pair of seal members ( ) from end surfaces ( ) thereof facing inside in the axial direction of a nut ( ) of a ball screw to intermediate portions of the seal members ( ), and foreign bodies removing slits ( ) are formed on the seal members ( ) from end surfaces ( ) thereof facing outside in the axial direction of the nut ( ) to intermediate portions thereof The lubricant retaining slits ( ) can positively trap the lubricant invading into the gap between the seal member ( ) and the screw shaft and returns the lubricant inside the nut ( ). The foreign bodies removing slits ( ) can remove the foreign bodies stored on the outer peripheral surface of the screw shaft and discharged outside the nut ( ).

Ball screw

A slide-feed drive part ( ) uses a stepping motor as a slide-feed motor for changing the position of a optical pick-up ( ) with respect to the rotation surface of an optical disk ( ), and has a micro-controller ( ) provided therein and a slide-feed motor controller ( ) both for correcting drive current waveforms to drive the stepping motor. Therefore, by correcting the motor driving waveforms, the optical pick-up ( ) can be linearly moved with respect to the rotation of the slide-feed motor ( ). It is thereby possible to do away with a position sensor and make a fine positional control of the optical pick-up ( ) with no variation. As a result of this, it is possible to provide an optical disk driving apparatus, an optical disk driving method, and an optical disk apparatus, which enhances the linearity of the rotation of the motor with a simple construction.

Optical disk apparatus capable of correcting the drive current waveforms of stepping motor

This invention relates to improvement of a ball screw unit in which a nut member meshes with a screw shaft via a plurality of balls circulating endlessly. The balls are disposed freely rotatably in line at a predetermined interval in a ball arranging member formed in a belt-like shape. If a relative rotation occurs between the nut member and screw shaft, the balls circulate in the infinite circulation path with the ball arranging member. Guide pieces are projected to both sides of the ball arranging member and guide grooves for accommodating each of the guide pieces are formed along the entire circumference of the infinite circulation path. Therefore, the ball arranging member is introduced by the guide grooves and circulates in the infinite circulation path without being fluttered.

Ball screw device

A ball screw comprises a screw shaft formed on an outer peripheral surface thereof with a spiral ball rolling groove, a nut member having an inner peripheral surface on which a spiral loaded ball rolling groove corresponding to the spiral ball rolling groove of the screw shaft is formed, both the spiral grooves constituting a loaded ball rolling passage in combination thereof when the screw shaft is fitted to the nut member, a number of balls rolling in the loaded ball rolling passage, and a return pipe having one end connected to one end of the loaded ball rolling passage and another end connected to another end of the loaded ball rolling passage so as to scoop the balls rolling in the loaded ball rolling passage at the one end of the return pipe and return the balls to the loaded ball rolling passage at the other one end of the return pipe. Cutouts, each having a width gradually reduced, are formed to both end portions of the return pipe so that the width of the cutout is gradually reduced towards the inside of the return pipe.

A ball screw assembly includes a screw shaft with a spiral groove, balls along the groove, a nut with the screw shaft relatively rotatable with the balls, and a seal device. A portion of each seal member is radially divided into blocks by plural slits so as to extend from one end surface directing outward in an axial direction of the nut to an axial intermediate portion of the seal member, each block having a pair of end faces, the end faces including one end face directed to a rotational direction of the nut with respect to the screw shaft when the screw shaft is screwed into the nut and another end face opposing to the other end face, this one end face being inclined so as to be gradually displaced, towards an outer peripheral side from an inner peripheral side of the seal member, in a direction reverse to the rotational direction with respect to a radial direction of the nut, and the other end face extending in this radial direction of the nut or in a direction inclined to a side reverse to the one end face with respect to the radial direction of the nut.

Growing community of inventors

Tokyo, Japan

Ryuji Takeda