Differential Roller Screw

• US 20120204665A1
• Filed: 09/29/2010
• Published: 08/16/2012
• Est. Priority Date: 10/16/2009
• Status: Active Grant

• Current Assignee: Thales SA
• Original Assignee: Thales SA
• Inventors: Baudasse, Yannick
• Granted Patent: US 8,544,357 B2
• Time in Patent Office: Days
• US Class Current: 74/424.92
• CPC Class Codes: F16H 2025/2075 Coaxial drive motors
• CPC Class Codes: F16H 25/2252 Planetary rollers between nut and screw
• CPC Class Codes: Y10T 74/19795 Parallel to shaft

Abstract

A differential roller screw comprises an outer nut, and rolling elements comprising a first set of rollers equipped with first grooves, the first set being arranged in a first cylindrical ring around the screw. The screw comprises a second set of rollers equipped with second grooves. The second set is arranged in a second cylindrical ring. The two cylindrical rings are coaxial. An intermediate cylindrical element is arranged between the two sets of rollers, the intermediate element comprising a first internal thread formed with a first pitch and having a first direction and a second external thread formed with a second pitch and having a second direction opposite the first direction.

Claims

1. A differential roller screw comprising an outer nut, rolling elements comprising a first set of rollers equipped with first grooves, the first set being arranged in a first cylindrical ring around the screw, the differential roller screw further comprising:

a second set of rollers equipped with second grooves, the second set being arranged in a second cylindrical ring, the two cylindrical rings being coaxial, and an intermediate cylindrical element being arranged between the two sets of rollers, the intermediate element comprising a first internal thread formed with a first pitch and having a first direction and a second external thread formed with a second pitch and having a second direction opposite the first direction.

2. The differential roller screw as claimed in claim 1, wherein the rollers are threaded, the threads being formed by the first and second grooves.

3. The differential roller screw as claimed in claim 1, wherein the first and second grooves are circular.

4. The differential roller screw as claimed in claim 1, wherein the cross-section of the grooves of the rollers is triangular.

5. The differential roller screw as claimed in claim 1, wherein the intermediate element is driven in rotation by a motor, the intermediate element moving in translation in the first direction, the nut being driven in translation in the second direction, the screw being fixed.

6. The differential roller screw as claimed in claim 1, wherein the intermediate element is driven in rotation by a motor, the intermediate element being connected to the motor and guiding it in rotation, the intermediate element moving in translation in the first direction, the screw being driven in translation in the second direction, the nut being fixed.

7. The differential roller screw as claimed in claim 1, wherein the nut is a hub.

8. The differential roller screw as claimed in claim 1, wherein the rollers are recirculating rollers, the rollers comprising a cam and a locking finger.

9. The differential roller screw as claimed in claim 1, wherein the rollers comprise two threaded circular parts at each end of the roller, the central part of the rollers having a smaller radius than the threaded parts.

10. The differential roller screw as claimed in claim 1, wherein the intermediate piece is connected to a central screw via the first set of peripheral rollers and to the external nut via the second set of peripheral rollers.

11. The differential roller screw as claimed in claim 1, wherein the first pitch differs from the second pitch.