BALL SCREW

Abstract

The invention relates to a ball screw including a spindle nut arranged on a lead screw, and balls, which roll on ball grooves of the spindle nut and of the lead screw, and a circumferential stop on the screw side and a circumferential stop on the nut side, the spindle nut being arranged in a sleeve surrounding the ball nut, the sleeve is formed from sheet metal by shaping and the nut-side circumferential stop is formed integrally on the sleeve.

Claims

1. A ball screw comprising a spindle nut arranged on a threaded spindle, balls that roll on ball grooves of the spindle nut and the threaded spindle, a spindle-side circumferential stop, and a nut-side circumferential stop, the spindle nut is arranged in a sleeve that surrounds the spindle nut and is formed from sheet metal by shaping, and the nut-side circumferential stop and a rotational lock are formed integrally on the sleeve.

2. The ball screw according to claim 1, wherein the sleeve is provided with a radial flange with a recess for leading through the spindle-side circumferential stop.

3. The ball screw according to claim 2, wherein the recess and the nut-side circumferential stop have, in a circumferential direction, a predetermined distance to each other, for determining a rotational position of the sleeve and the spindle nut in an aligned position of the spindle-side circumferential stop and the recess relative to each other.

4. The ball screw according to claim 1, wherein the rotational lock is formed by a hollow bump formed on the sleeve that projects radially from a cylindrical circumferential surface of the sleeve.

5. The ball screw according to claim 1, wherein the nut-side circumferential stop is formed on an end-side radial flange of the sleeve, and the end-side radial flange is provided with a step on which a stop surface of the nut-side circumferential stop is formed.

6. The ball screw according to claim 5, wherein the radial flange is arranged in a helical shape about a spindle axis of the threaded spindle, and the step is formed by an axial offset of the radial flange.

7. The ball screw according to claim 1, wherein the sleeve has, on one end side thereof, a radially inward directed crescent-shaped projection that extends in a circumferential direction from a radially tapered end to a radially expanded end, and a stop surface of the nut-side circumferential stop is formed on the radially expanded end.

8. The ball screw according to claim 1, wherein the balls are arranged in a screw-shaped ball channel wound about a spindle axis, a start and an end of the ball channel are connected to each other by a deflection body in an endless manner, and the sleeve surrounds the deflection body and is held captively on the spindle nut.

9. The ball screw according to claim 1, wherein the sleeve is connected to the spindle nut by at least one of a friction-fit connection or by a positive-locking connection for transmitting torques.

10. A method for installing the ball screw according to claim 1, comprising the following steps: mounting the spindle nut and the threaded spindle with the balls; setting up an aligned position of the sleeve and the spindle-side circumferential stop in which the recess and the spindle-side circumferential stop are aligned with each other; and in this aligned position, arranging the sleeve locked in rotation on the spindle nut.

11. A braking device of a motor vehicle with a ball screw according to claim 1.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Below, the invention will be explained in more detail with reference to embodiments shown in a total of 13 figures. Shown are:

[0027] FIGS. 1 and 2 a first embodiment of a ball screw in two different rotational positions,

[0028] FIGS. 3 to 5 an individual part of the embodiment according to FIG. 1 in different view,

[0029] FIGS. 6 to 8 a variant of the individual part of a second embodiment in different views,

[0030] FIGS. 9 to 11 another variant of the individual part of a third embodiment in different views,

[0031] FIG. 12 a detail of the ball screw according to the invention from FIG. 1, and

[0032] FIG. 13 a detail of only the spindle nut of the ball screw from FIG. 12.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0033] The ball screw shown in FIGS. 1 and 2 is provided with a spindle nut 2 arranged on a threaded spindle 1. The FIGS. 12 and 13 show longitudinal sections of the ball screw with this spindle nut 2. In a known way, balls 13 roll on ball grooves 14, 15 of the spindle nut 2, as well as the threaded spindle 1. FIG. 13 clearly shows the so-called individual deflectors. Deflection pieces 25 are arranged in multiple pass-through openings 24 arranged distributed around the circumference of the spindle nut 2. The balls 13 revolve in helical-shaped ball channels 26 wound about the spindle axis, wherein each deflection piece 25 connects a start and an end of a common winding of the ball channel 26 endlessly to each other.

[0034] The threaded spindle 1 is provided with a spindle-side circumferential stop 3 that has a stop surface 4 that is constructed integrally on a stop plate 5 arranged locked in rotation on the threaded spindle 1. The spindle nut 2 can have a cylindrical lateral surface.

[0035] FIGS. 1 and 2 show that a sleeve 6 is arranged on the spindle nut 2 that is pressed onto the spindle nut 2 in the embodiment. A mounting can be realized in a non-positive and/or positive-locking connection. In each case, the sleeve 6 can transmit torque between the sleeve 6 and the spindle nut 2. This sleeve 6 produced from thin-wall sheet metal in a shaping process is provided with an integrally formed nut-side circumferential stop 7 that has a stop surface 8.

[0036] The sleeve 6 is further provided with integrally formed bumps 9 that are arranged distributed over the circumference. These bumps 9 are used as anti-twist protection 27 of the spindle nut 2. The bumps can engage, for example, in grooves of a not shown component (housing, piston), so that the spindle nut 2 is locked in rotation relative to this component.

[0037] FIG. 1 shows a stop situation in which the circumferential stops 3, 7 contact each other. FIG. 2 shows a rotational position of the threaded spindle 1 and spindle nut 2 outside of the stop situation.

[0038] FIGS. 3 to 5 show the sleeve 6 as an individual part. This sleeve 6 is formed from sheet metal by shaping processes. The circumferential stop 7 is formed on an end-side radial flange 10 of the sleeve 6, wherein the radial flange 10 is provided with a step 11 formed in the axial direction on which the stop surface 8 of the nut-side circumferential stop 7 is formed. The step 11 is formed by an axial offset of the radial flange 10.

[0039] By shaping and bending processes of the sheet metal, the sleeve 6 can be produced in an economically favorable way.

[0040] FIG. 4 clearly shows a recess 12 on the radial flange 10. This radially inwardly open recess 12 is adapted to the contour of the stop plate 5 with its radially projecting, spindle-side circumferential stop. In this way, the sleeve 6 can be mounted, after which the threaded spindle 1 is mounted together with the spindle plate 5 and the spindle nut 2. The recess 12 and the circumferential stop 7 of the radial flange 10 are arranged circumferentially in their position spaced apart from each other such that the sleeve 6 is set on the spindle nut 2 and can be held or attached in a defined alignment position with reference to the stop plate 5. In this alignment position, the recess 12 and the stop plate 5 align with each other with the radially projecting stop surface 4, so that the sleeve 6 can be pushed over the stop plate 5. In this alignment position it is guaranteed that the spindle nut 2 provided with the sleeve 6 cannot jam with the stop plate 5. This is because the stop surfaces 4 and 8 contact each other before a jamming contact can occur.

[0041] FIG. 5 clearly shows that the radial flange 10 is arranged in a helical shape about the spindle axis of the threaded spindle. The helical shape can also be generated by a simple shaping process. The step 11 can be produced in an economically favorable way by bending and shaping processes of the thin-wall sheet metal.

[0042] FIGS. 6 to 8 show one variant of the sleeve 8 of the ball screw according to the invention, which differs from the previously described sleeve 8 essentially by a modified radial flange 16. The radial flange 16 has a clearly increased wall thickness relative to the previously described radial flange. Just like in the previously described embodiment, a circumferential stop 17 is formed by an axial offset of the radial flange 16 in the form of a step 21. The increased wall thickness can be useful if the circumferential stop must absorb significantly increased circumferential forces. A stop surface 22 is formed on this step 21 for the spindle-side circumferential stop.

[0043] FIGS. 9 to 11 show another variant of the sleeve 8 that differs from the previously described embodiments in that, instead of a radial flange, an approximately crescent-shaped, radially inward directed projection 18 is formed on an end side of the sleeve 8. The projection 18 extends in the circumferential direction starting from a radially tapered end toward a radially expanded end. On the radially expanded end there is a circumferential stop 19 whose stop surface 23 corresponds to the wall thickness of the crescent-shaped projection 18. On its tapered end, the crescent-shaped projection 18 transitions at least approximately tangentially into the hollow-cylindrical lateral surface section of the sleeve 8.

[0044] This projection 18 can be formed, for example, by stamping of a thick-wall base of the sleeve 8. In this case, this projection 18 can have, in the axial direction, a wall thickness that is greater than the wall thickness of the sleeve 8. The wall thickness of the projection 18 determines, in this case, the size of the stop surface 23. This sleeve 8 can be produced in a favorable way in a shaping and stamping process: first the sleeve 8 is formed with a thick-wall base formed on the end side. In a stamping process, material can then be stamped out from this base, in order to form the mentioned crescent-shaped projection 18.