Adjusting drive and method for producing an adjusting drive

Abstract

An adjusting drive, in particular for a steering column adjuster or a vehicle seat of a motor vehicle, and a method for producing an adjusting drive, are provided in which an axial play of the output shaft is reliably and permanently compensated. The compensating element for ensuring the axial-play-free arrangement of the output shaft is connected, in its operating position, to the housing by ultrasound welding.

Claims

1. An adjusting drive, comprising: a housing; an output shaft rotatably mounted in the housing; and a wedge-shaped compensating element to prevent axial play of the output shaft, wherein the compensating element, in an operating position, is braced against the housing and an axial stop of the output shaft, wherein the compensating element, in the operating position, is connected to the housing by ultrasonic welding to secure the axial-play-free arrangement of the output shaft, wherein the compensating element is connected to a cover of the housing by ultrasonic welding.

2. The adjusting drive according to claim 1, wherein the compensating element has a U-shaped seat opening that encompasses the output shaft in the region of a shaft shoulder forming an axial stop.

3. The adjusting drive according to claim 2, wherein the compensating element, in the operating position, has a support surface facing away from the axial stop that lies against a contact surface of the housing.

4. The adjusting drive according to claim 3, wherein, corresponding to the wedge shape of the compensating element, the contact surface is contrarily at an angle relative to a plane running vertical to the output shaft.

5. The adjusting drive according to claim 3, wherein the contact surface is formed integrally with the housing.

6. The adjusting drive according to claim 1, wherein the compensating element has an actuating section that extends out of a housing opening.

7. The adjusting drive according to claim 1, wherein the compensating element has a contour to align it.

8. The adjusting drive according to claim 1, wherein a safety bolt is embedded in the region of the ultrasonic weld in the housing.

9. The adjusting drive according to claim 8, wherein the safety bolt has at least one of an end section that narrows toward the compensating element and a cross-section that changes in the longitudinal axial direction, and a cross-section that deviates from a circular shape.

10. The adjusting drive according to claim 8, wherein the safety bolt is designed to be coupled to an ultrasonic vibration generator and to transmit ultrasonic vibrations into at least one of the housing and the compensating element.

Description

(1) An exemplary embodiment of the invention is explained in the following with reference to the drawings. In the figures:

(2) FIG. 1 shows a perspective view of an adjusting device with a housing and an output shaft extending out of the housing;

(3) FIG. 2 shows a plan view of the adjusting device from FIG. 1;

(4) FIG. 3 shows a view of a section along intersecting line A-A from FIG. 2;

(5) FIG. 4 shows a perspective view of a housing cover of the housing of the adjusting device from FIG. 1;

(6) FIG. 5 shows a perspective view of a compensating element of the adjusting device from FIG. 1;

(7) FIG. 6 shows a perspective view of the housing cover from FIG. 4 and the compensating element from FIG. 5 in an assembled position;

(8) FIG. 7 shows a view of a section of an additional embodiment of an adjusting device with a safety bolt, and

(9) FIG. 8 shows a perspective view of the safety bolt from FIG. 7.

(10) An exemplary embodiment of an adjusting drive 1 as well as its components are portrayed in FIGS. 1 to 6. The adjusting drive 1 has a housing 2 formed by a main housing body 10 and a housing cover 3 on which an output shaft 4 of the adjusting drive 1 is rotatably mounted. The output shaft 4 that is connectable to an adjustable vehicle component (not shown) can be driven by means of a pinion 12 which is only sketched.

(11) For an axial-play-free arrangement of the output shaft 4 in the housing 2 that is required for smooth operation, the adjusting drive 1 has a wedge-shaped compensating element 5 that, when in the operating position shown in FIGS. 1 and 3, secures the output shaft 4 in an axial-play-free position. A stop surface 16 of the compensating element 5 in an operating position lies against an axial stop 11 formed by the pinion 12, and a support surface 13 lies against an angled contact surface 17corresponding to the wedge shape of the compensation element 5of an interior of the main housing body 10, wherein to simultaneously achieve an axial-play-free arrangement of the output shaft 4, a conical, tapering support bearing 18 of the shaft end arranged within the housing 2 lies against the inner housing opposite the contact surface 17. The position of the output shaft 4 in an axial direction is determined as a function of the radial position of the wedge-shaped compensating element 5 relative to the output shaft 4 such that, by shifting the compensating element 5 in a radial direction, the output shaft 4 is moved into a play-free position.

(12) The support bearing 18, like the region of the main housing body 10 against which the support bearing 18 lies against the inner housing wall, can have any design to achieve a secure position as well as minimal friction. Accordingly, the main housing body 10 can for example be provided in the region of the support 18 with a preferably metal thrust washer (not shown) that is separately attached to the main housing body 10 or embedded in it during its manufacturing process. Alternately to the portrayed conical design, the support bearing 18 can be formed by a sphere that is rotatably arranged on the shaft end.

(13) To secure the operating position of the compensating element 5 relative to the housing 2, the compensating element 5 is connected by a bar 8 of the housing cover 3, that extends in a radial direction toward the output shaft 4, to the housing cover 3 by means of an ultrasonic welding point 9. The axial-play-free position of the output shaft 4 is secured by means of the positionally stable connection of the main housing body 10 and housing cover 3 that, jointly with the main housing body 10, forms the radial bearing of the output shaft 4 by an arc-shaped section of the bar 8 corresponding to the cross-section of the output shaft 4.

(14) The position of the compensating element 5 on the output shaft 4 is determined, among other things, by a U-shaped seat-opening 15 that, in the operating position, extends in the region around the output shaft 4. A projection 6 serves to displace the compensating element out of an initial position into the operating position and, when viewed in a radial direction, extends on the side of the compensating element 5 opposite the U-shaped seat opening 15 and, when the compensating element 5 is in the pre-mounted and mounted position, projects through an opening 7 in the housing cover 3. In the pre-mounted position, the compensating element 5 can be shoved toward the output shaft 4 into the operating positionin which the compensating element 5 is permanently connected to the housing cover 3 by ultrasonic weldingby comfortably shifting the projection 6 that projects out of the housing opening 7 of the already mounted housing 2.

(15) To achieve minimal friction between the axial stop 11 and the stop surface 16, they can be made for example from suitable materials or provided with low friction coatings. According to an embodiment not shown, a bearing, such as a ball bearing, can also be arranged between the pinion 12 and the compensating element 5 which enables particularly low-friction operation.

(16) A contour 14 arranged on one side of the compensating element 5 that interacts with a corresponding recess in the housing 2 facilitates a single installation position of the compensating element 5 relative to the output shaft 4, thus ensuring that the support surface 13 comes into flat contact with a correspondingly angled contact surface 17 on an inner housing wall of the main housing body 8.

(17) FIG. 7 shows a view of a section of an additional embodiment of an adjusting device 1 having a safety bolt 19, wherein the safety bolt 19 extends through the bar 8 of the housing 2 into the compensating element 5, such that the safety bolt 19 also secures the position of the compensating element 5 relative to the housing 2. The safety bolt 19 also serves to introduce ultrasonic vibrations into the compensating element 5 and the housing 2, which plastifies, i.e., melts, the region around the safety bolt 19, and ultrasonic welding occurs. To introduce ultrasonic vibration, the safety bolt 19 is coupled to a sonotrode (not shown) before or after being arranged in the housing 2 and the compensating element 5.

(18) To ensure a particularly reliable arrangement of the safety bolt 19, it has a type of thread 20 on its perimeter, and the plastified plastic flows into its gaps during ultrasonic welding which, in addition to a keyed connection, also yields an integral connection of a particularly high quality.

(19) During the ultrasonic welding process, the ultrasonic vibrations are converted into mechanical oscillation energy by means of a sound transducer. The heat required for plastification during ultrasonic welding is achieved by introducing mechanical oscillations, and these are fed to the components 5, 8, 19 to be welded under a controlled pressure of a sonotrode. Given its design, the connecting bolt 19 serves to introduce heat in a targeted manner, wherein heat is generated by molecular and interfacial friction on the flanks of the thread 20, in the region of which the plastic begins to melt, thus causing the plastified plastic to flow into the region between the flanks of the thread 20.

(20) To enable an effective arrangement of the safety bolt, the housing cover 3 provided to be received on the housing 2 has a pilot hole which is adapted to the compensating element 5.