US 11,892,062 B2
Preload detectable screw device
Yuji Kubota, Tokyo (JP); Hirofumi Suzuki, Tokyo (JP); Takamitsu Tomiyama, Tokyo (JP); and Yuta Tsujisawa, Tokyo (JP)
Assigned to THK CO., LTD., Tokyo (JP)
Appl. No. 17/428,731
Filed by THK CO., LTD., Tokyo (JP)
PCT Filed Jan. 20, 2020, PCT No. PCT/JP2020/001652
§ 371(c)(1), (2) Date Aug. 5, 2021,
PCT Pub. No. WO2020/162145, PCT Pub. Date Aug. 13, 2020.
Claims priority of application No. 2019-019349 (JP), filed on Feb. 6, 2019.
Prior Publication US 2022/0128136 A1, Apr. 28, 2022
Int. Cl. F16H 25/22 (2006.01); F16H 57/01 (2012.01)
CPC F16H 25/2204 (2013.01) [F16H 57/01 (2013.01); F16H 2057/012 (2013.01)] 12 Claims
OG exemplary drawing
 
1. A preload detectable screw device comprising:
a screw shaft including an outer helical groove;
a single nut fitted on the screw shaft, the single 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 single nut,
wherein at least one hole is provided between an attachment surface, to which the strain sensor is attached, of the single nut and an inner surface, to which the inner groove is formed, of the single nut.