Reverse input blocking clutch and actuator

Patent metadata

Field	Value
Publication number	US-11428278-B2
Application number	US-201917053902-A
Country	US
Kind code	B2
Filing date	Apr 26, 2019
Priority date	May 7, 2018
Publication date	Aug 30, 2022
Grant date	Aug 30, 2022

Abstract

A reverse input blocking clutch includes an input member, an output member, a pressed member, and an engaging member. When a rotational torque is inputted to the input member, the engaging member moves in a direction away from a pressed surface of the pressed member due to engagement with the input member, and transmits the rotational torque inputted to the input member to the output member due to engagement with the output member; and when rotational torque is reversely inputted to the output member, moves in the direction closer to the pressed surface based on engagement with the output member, and by being pressed against the pressed surface does not transmit the rotational torque reversely inputted to the output member to the input member, or transmits only part thereof to the input member due to engagement with the input member.

First claim

The invention claimed is:

1. An actuator comprising
a rotational linear motion conversion mechanism, and
a reverse input blocking clutch having a locking mechanism; wherein
the rotational linear motion conversion mechanism comprises a screw shaft having a male-side engaging portion on an outer circumferential surface thereof and a nut having a female-side engaging portion on an inner circumferential surface thereof, and the male-side engaging portion and the female-side engaging portion are engaged with each other directly or via a plurality of intermediate engaging members;
the locking mechanism comprises a pressed member, an input engaging portion, an output engaging portion, and an engaging member;
the pressed member has a cylindrical pressed surface on the inner circumferential surface thereof;
the input engaging portion has a center axis of rotation that is coaxial with the center axis of the pressed surface, and is arranged on the inner side in the radial direction of the pressed surface;
the output engaging portion has a center axis of rotation that is coaxial with the center axis of the pressed surface, and is arranged on the inner side in the radial direction of the pressed surface and further on the inner side in the radial direction than the input engaging portion;
the engaging member is arranged on the inner side in the radial direction of the pressed surface, and when a rotational torque is inputted to the input engaging portion, moves in a direction away from the pressed surface due to the engagement with the input engaging portion and transmits the rotational torque inputted to the input engaging portion to the output engaging portion due to engagement with the output engaging portion; whereas, when rotational torque is reversely inputted to the output engaging portion, the engaging member moves in a direction close to the pressed surface due to engagement with the output engaging portion, and by being pressed against the pressed surface, does not transmit the rotational torque that is reversely inputted to the output engaging portion to the input engaging portion, or transmits part of the rotational torque that is reversely inputted to the output engaging portion due to the engagement with the input engaging portion and blocks the remaining part;
the locking mechanism is arranged at a portion where the output engaging portion is connected to the nut so as to be able to transmit torque, and is arranged around the screw shaft in a portion separated in the axial direction from the female-side engaging portion; and
the inner diameter dimension of the output engaging portion is smaller than the outer diameter dimension of a range in the axial direction in which the female-side engaging portion exists in the nut.

2. The actuator according to claim 1 , wherein
the engaging member is configured by a pair of engaging members, and the output engaging portion is arranged so as to be sandwiched from both sides in the radial direction by the pair of engaging members.

3. The actuator according to claim 1 , wherein
the engaging member has a pressing surface that is pressed against the pressed surface, and the pressing surface has a radius of curvature that is smaller than that of the pressed surface and is configured by a pair of arc-shaped convex surfaces separated from each other in the circumferential direction.

4. The actuator according to claim 1 , wherein
a reduction mechanism for increasing the rotational torque inputted to the input engaging portion is provided.

5. The actuator according to claim 4 , wherein
the output unit of the reduction mechanism is connected to the input engaging portion so as to be able to transmit torque; and
the reduction mechanism and the locking mechanism are arranged around the screw shaft so as to be adjacent to each other in the axial direction.

6. The actuator according to claim 1 , wherein
an electric motor that is a generating source of rotational torque that is inputted to the input engaging portion is provided.

7. The actuator according to claim 1 , wherein
the rotational linear motion conversion mechanism is a ball screw mechanism;
the male-side engaging portion is a male-side spiral groove;
the female-side engaging portion is a female-side spiral groove;
each of the intermediate engaging members is a ball; and
by arranging each of the balls between the male-side spiral groove and the female-side spiral groove, the male-side spiral groove and the female-side spiral groove engage with each other via each of the balls.

8. The actuator according to claim 1 , wherein
the rotational linear motion conversion mechanism is a planetary roller screw mechanism;
the male-side engaging portion is a male screw portion;
the female-side engaging portion is a female screw portion;
each of the intermediate engaging members is a planetary roller having a roller screw portion on the outer circumferential surface thereof; and
by each roller screw portion of the planetary roller engaging with both the male screw portion and the female screw portion, the male threaded portion and the female threaded portion engage with each other via each of the planetary rollers.

9. A reverse input blocking clutch, comprising:
a pressed member having a cylindrical concave-shaped pressed surface having a center axis;
an input member having an input engaging portion arranged on an inner side in a radial direction of the pressed surface and having a center axis of rotation that is coaxial with the central axis of the pressed surface;
an output member having an output engaging portion arranged further on the inner side in the radial direction of the pressed surface than the input engaging portion and having a center axis of rotation that is coaxial with the pressed surface; and
an engaging member having a first portion arranged on the inner side in the radial direction of the pressed surface at a position located in the radial direction between the input engaging portion and the output engaging portion, and a pair of second portions arranged at positions on both sides in a circumferential direction from the position located in the radial direction between the input engaging portion and the output engaging portion;
wherein
the engaging member is configured so that in a case where rotational torque is inputted to the input member, the engaging members moves in a direction away from the pressed surface due to the input engaging portion engaging with the first portion, and by the first portion engaging with the output engaging portion, transmits the rotational torque that is inputted to the input member to the output member; and in a case where rotational torque is reversely inputted to the output member, the engaging member moves in a direction toward the pressed surface due to the output engaging portion engaging with the first portion, and by the pair of second portions being pressed against the pressed surface, does not transmit the rotational torque that is reversely inputted to the output member to the input member, or transmits a part of the rotational torque that is reversely inputted to the output member, to the input member, and blocks a remaining part thereof;
in a case where rotational torque is reversely inputted to the output member, a pair of contact portions where the pair of second portions and the pressed surface come in contact are positioned on sides closer to the center axis of the pressed surface than a specified portion with respect to a direction of a bisector of tangent lines of the pressed surface at each contact portion of the pair of contact portions, and the specified portion is a portion of the first portion with which the input engaging portion engage when a rotational to

Assignees

• Nsk Ltd

Inventors

• Daikoku Yuya
• Kishida Hirotaka
• Hashiguchi Hiroki
• Toyoda Toshirou

Classifications

• F16D41/084

  the intermediate coupling members wedging by pivoting or rocking · CPC title

• F16D45/00 Primary

  Freewheels or freewheel clutches combined with automatic clutches · CPC title

• F16H25/2266

  arranged substantially in parallel to the screw shaft axis (planetary rollers F16H25/2252) · CPC title

• F16H25/2252

  Planetary rollers between nut and screw · CPC title

• F16H25/2204 Primary

  with balls · CPC title