Patent ID: 11892062
Assignee: THK CO., LTD.
Field: Mechanical elements (Mechanical engineering)
Classification: CPC F | IPC F

Claim 1:
2. A preload detectable screw device comprising:
a screw shaft including an outer helical groove;
a nut fitted on the screw shaft, the nut including 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 in the passage and the return path; and
a strain sensor attached to an outer surface of the nut,
wherein at least one hole is provided between an attachment surface, to which the strain sensor is attached, of the nut and an inner surface of the nut,
wherein the screw device uses the plurality of rolling elements that are larger than the passage to provide oversized ball preloading, and
the strain sensor detects strain on the nut at least in a circumferential direction thereof.