BALL SCREW DRIVE AND ASSOCIATED ELECTROMECHANICAL ACTUATOR

• US 20180017147A1
• Filed: 01/14/2016
• Published: 01/18/2018
• Est. Priority Date: 01/26/2015
• Status: Active Grant

• Current Assignee: Schaeffler Technologies AG & Co.KG (INA-Holding Schaeffler GmbH & Co. KG)
• Original Assignee: Schaeffler Technologies AG & Co.KG (INA-Holding Schaeffler GmbH & Co. KG)
• Inventors: KREUTZER, Mario, MARTY, Christian, SCHMEIKO, Harry, GOETZ, Manfred
• Granted Patent: US 10,626,966 B2
• Time in Patent Office: Days
• CPC Class Codes: B60T 13/741 acting on an ultimate actuator
• CPC Class Codes: B60T 13/745 acting on a hydraulic system, e.g. a master cylinder
• CPC Class Codes: F16D 2125/36 Helical cams, Ball-rotating ramps
• CPC Class Codes: F16D 2125/40 Screw-and-nut
• CPC Class Codes: F16D 65/14 Actuating mechanisms for brakes; Means for initiating operation at a predetermined position brake control systems, parts thereof B60T
• CPC Class Codes: F16H 25/2223 Cross over deflectors between adjacent thread turns, e.g. S-form deflectors connecting neighbouring threads
• CPC Class Codes: F16H 25/2233 with cages or means to hold the balls in position

Abstract

A ball screw of an electromechanical brake comprising a ball screw nut disposed on a spindle, wherein the spindle includes complementary tracks formed on the spindle and the ball screw nut. The ball screw further includes a race that includes a plurality of ball pockets spaced apart from one another and a protruding section that includes a concave bearing surface, a ball housed between the concave bearing surface and an end section of a first spring element for a main load direction, and a second spring element for a return stroke direction, wherein the second spring element includes a second spring end section in contact with an opposite side of the bearing surface.

Claims

1. A ball screw comprising:

a ball screw nut disposed on a spindle; and

complementary tracks formed on the spindle and the ball screw nut, in which a ball is accommodated in a race and at least one spring element for generating a reset force are disposed, wherein the ball is disposed between the race and the at least one spring element.

2. The ball screw of claim 1, wherein a diameter of the ball disposed between the race is large enough that it is a supporting ball.

3. The ball screw of claim 1, wherein a diameter of the ball disposed between the race is small enough that it is not a supporting ball.

4. The ball screw of claim 1, wherein the race includes at least one concave bearing surface adapted to the outer contour of the ball.

5. The ball screw of claim 1, wherein the ball screw includes at least two spring elements, disposed such that they generate opposing reset forces.

6. The ball screw of claim 1, wherein the ball screw includes at least two spring elements disposed axially offset to one another and disposed such that the two spring elements generate reset forces acting in the same direction.

7. The ball screw of claim 1, wherein a length of the at least one spring element is between one half of a circumference and approximates three quarters of the circumference of the track.

8. The ball screw of claim 1, wherein the complimentary tracks on the spindle and the ball screw nut are configured to accommodate the balls in the race to be retained therein.

9. The ball screw of claim 1, wherein the race includes ball pockets that are radially offset.

10. (canceled)

11. A ball screw of an electromechanical brake, comprising:

a ball screw nut disposed on a spindle, wherein the spindle includes complementary tracks formed on the spindle and the ball screw nut;

a race that includes a plurality of ball pockets spaced apart from one another and a protruding section that includes a concave bearing surface;

a ball housed between the concave bearing surface and an end section of a first spring element for a main load direction; and

a second spring element for a return stroke direction, wherein the second spring element includes a second spring end section in contact with an opposite side of the bearing surface.

12. A ball screw of an electromechanical brake, comprising:

a ball screw nut disposed on a spindle, wherein the spindle includes complementary tracks formed on the spindle and the ball screw nut; and

a ball housed between a race and an end section of at least one spring element.

13. The ball screw of claim 12, wherein a diameter of the ball includes an outer diameter configured to roll on the tracks when the ball screw is moved.

14. The ball screw of claim 12, wherein the at least one spring element retains a raceway configured to allow the ball to roll when the spindle moves in relation to the ball screw nut.

15. The ball screw of claim 12, wherein the race includes a plurality of ball pockets spaced apart from one another and configured to receive the ball.

16. The ball screw of claim 15, wherein the ball pockets are radially offset toward the outside of a circumferential surface of the race.

17. The ball screw of claim 15, wherein the ball pockets are configured to retain the ball on the spindle by the race, such that the ball screw nut can be removed without the balls falling.

18. The ball screw of claim 15, wherein the ball pockets are radially offset toward the inside with respect to the race.

19. The ball screw of claim 12, wherein the race includes a bearing surface of a section extending in an axial direction of the race, wherein a second spring element is disposed on an opposite side of the bearing surface and the second spring element exerts a force directed opposite the force generated by a first spring element.

20. The ball screw of claim 12, wherein the spring element is a helical compression spring.