US 12,085,165 B1
Rotary-linear motion converter and shift actuator
Hironori Mizuki, Fujisawa (JP); Masayoshi Shimizuya, Fujisawa (JP); and Susumu Tanaka, Fujisawa (JP)
Assigned to NSK LTD., Tokyo (JP)
Appl. No. 18/681,735
Filed by NSK Ltd., Tokyo (JP)
PCT Filed Jul. 20, 2023, PCT No. PCT/JP2023/026590
§ 371(c)(1), (2) Date Feb. 6, 2024,
.
Int. Cl. F16H 63/06 (2006.01); F16H 25/22 (2006.01)
CPC F16H 63/062 (2013.01) [F16H 25/2219 (2013.01)] 11 Claims
OG exemplary drawing
 
1. A rotary-linear motion converter, including:
a housing;
a ball screw mechanism including a screw shaft having a spiral shaft-side ball screw groove on an outer-circumferential surface thereof, a nut having a spiral nut-side ball screw groove on an inner-circumferential surface thereof, and a plurality of balls arranged so as to roll in a load path consisting of the nut-side ball screw groove and the shaft-side ball screw groove; and
an output shaft that is supported so as to move in an axial direction with respect to the housing but not to relatively rotate,
wherein one of the screw shaft and the nut configures a linear motion member that undergoes a linear motion during use, and the other of the screw shaft and the nut configures a rotary member that undergoes a rotary motion during use, and
the linear motion member and the output shaft are connected by a connecting structure, the connecting structure, including:
a first member, which is one of the linear motion member and the output shaft, having a male screw portion on an outer-circumferential surface thereof;
a second member, which is the other of the linear motion member and the out put shaft, having a female screw portion on an inner-circumferential surface that is screwed with the male screw portion;
a rotation restraining member placed between the first member and the second member and preventing relative rotation between the first member and the second member; and
an elastic member applying elasticity in an axial direction between the first member and the second member.