Thk Co., Ltd.

Takamitsu Tomiyama

Yuji Kubota

Hirofumi Suzuki

Yuta Tsujisawa

A screw device is provided which applies preload with a single nut and can easily detect preload. The screw device of includes: a screw shaft having an outer helical groove; a nut fitted on the screw shaft, the nut having an inner helical groove, and a return path to which a passage formed between the outer groove and the inner groove is connected; a plurality of rolling elements placed between the passage and the return path; and a strain sensor attached to an outer surface of the nut. At least one hole is provided between an attachment surface, to which the strain sensor is attached, of the nut and/or a vicinity thereof and an inner surface of the nut.

Preload detectable screw device

In a screw device where a shim is disposed between two nuts, a screw device that can detect preload is provided. The preload detectable screw device includes: two nuts; a shim sandwiched and compressed between the two nuts; a coupling portion configured to couple the two nuts in such a manner as to be incapable of relative rotation to each other; and a force sensor for detecting preload. A contact surface of at least one of the two nuts with the shim is provided with a recess, spaced apart from the coupling portion, in such a manner as to reduce the contact area. The force sensor is attached near the recess on an outer surface of the shim.

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Tokyo, Japan

Takamitsu Tomiyama