Seiko Seiki Kabushiki Kaisha

Seiko Instruments Inc

Hiroyuki Kihara

Hideki Omori

Masaharu Sugiyama

Tatsuji Saigo

Isaoi Ogawa

Hideo Iwadate

A multistage fine-hole machining device has lap stations for lapping an inner surface defining a through-hole of a workpiece. Each of the lap stations has a passing unit for passing wire through the through-hole of the workpiece, a supply unit for supplying a polishing material to the wire, and a sliding unit for effecting relative sliding movement between the workpiece and the wire while the wire is passed through the through-hole of the workpiece and is supplied with the polishing material to thereby lap the inner surface of the workpiece with the polishing material and enlarge the diameter of the through-hole. A transfer device successively transfers the workpiece to each of the lap stations to lap the inner surface of the workpiece at each of the lap stations during the lapping operation for successively enlarging the diameter of the through-hole to a preselected diameter.

Multistage fine hole machining method and device

A spindle apparatus comprises a main shaft mounted for rotary movement, a rotating device for rotating the main shaft about an axis, a vibration device for vibrating the main shaft, a detecting device for detecting a displacement of the main shaft when the main shaft is vibrated by the vibration device and providing an output signal indicative of the displacement of the main shaft, a calculating device for calculating an allowable revolution speed of the main shaft on the basis of the output signal of the detecting device, and a drive source for driving the rotating device to rotate the main shaft within a speed range which does not exceed the allowable revolution speed. When an end of the main shaft is vibrated by the vibration device, a displacement of the vibrated main shaft is detected by the detecting device which provides an output signal indicative of the detected displacement. The calculating device calculates an allowable revolution speed of the main shaft on the basis of the output signal of the detecting device and outputs the calculated allowable revolution speed to the drive source. The drive source drives the rotating device to rotate the main shaft within a speed range which does not exceed the allowable revolution speed.

Method and apparatus for computing allowable spindle rotation speed

The control system is provided in a grinding machine composed of an axially movable rotational shaft having a grinding tool and being supported magnetically by electromagnets. The control system includes a target position modifying controller for modifying or shifting a reference target levitating position of the rotational shaft in a retreating direction away from a workpiece reaches a predetermined amount. The control system further includes a rigidity modifying controller operative during quick feed operation of the rotational shaft for making a rigidity of the rotational shaft lower than that in the grinding operation by adjusting exciting currents of the electromagnets. The control system still further includes a dressing controller operative during dressing of a new grinding tool for detecting that the grinding tool begins to touch a dresser and for judging that the dressing is completed just when an arithmetic value calculated based on the detection reaches a predetermined value.

Control system of grinding machine

A control system is provided in a grinding machine composed of an axially movable rotational shaft having a grinding tool and being supported magnetically by electromagnets. The control system includes a target position modifying controller for modifying or shifting a reference target levitating position of the rotational shaft in a retreating direction away from a workpiece reaches a predetermined amount. The control system further includes a rigidity modifying controller operative during quick feed operation of the rotational shaft for making a rigidity of the rotational shaft lower than that in the grinding operation by adjusting exciting currents of the electromagnets. The control system still further includes a dressing controller operative during dressing of a new grinding tool for detecting that the grinding tool begins to touch a dresser and for judging that the dressing is completed just when an arithmetic value calculated based on the detection reaches a predetermined value.

A grinder with a deflection sensor for controlling the grinding work conditions based on an amount of deflection of a grinding shaft occurring in the normal direction relative to the grinding shaft which is detected by measuring inductance with the deflection sensor. Based on a deflection of the grinding shaft detected during grinding work, the feed of the grinder is controlled, and the sharpness of the grinder is determined based on changes of the detected deflection amount during spark-out, moreover an error in the signal from the deflection detector caused by a thermal change can be compensated, whereby grinding work is carried out under an optimum condition, and the grinding accuracy and efficiency are improved.

Method and apparatus for controlling a grinder having a spindle with

An internal grinding machine for grinding the inner surface of a work comprises a traverser table (11) mounted on a bed (10) for sliding movement in the longitudinal direction of the bed, a grinding head (15) mounted on the table for free position adjustment in the longitudinal direction, and a grinder shaft spindle (16) fixed to the upper surface of the grinding head (15) and provided on the front end surface thereof with a grinder shaft which carries at its end a grinder (19), the traverser table being adapted to slide so as to bring the grinder to a predetermined position with respect to the work, wherein the grinding head being arranged such that its rear end can swing to the left and right about the center (17) of the front end thereof, the rear end of the grinding head being connected to an eccentric cam mechanism (21) which in turn is connected to a driving portion (22), so that the grinding head is swung by a predetermined angle in accordance with the amount of eccentricity of the eccentric cam mechanism obtained in accordance with the operation of the driving portion. Accordingly, the internal grinding machine of this invention is capable of effecting grinding of the inner surface with high degree of precision (cylindricity and straightness), in the manner where a quill is made to be positioned at a specified angle in the region where the quill tends to flex during its traversing movement.

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Narashino, Japan

Hiroyuki Kihara