Rack-and-pinion gear mechanism

1. A rack-and-pinion gear mechanism comprising:

a housing;

a pinion shaft rotatably mounted in the housing;

a rack mounted in the housing and operatively connected to the pinion shaft so as to be longitudinally displaceable; and

a counter-pressure device to compensate for reaction forces between the pinion shaft and the rack, said counter-pressure device comprising a thrust piece, an adjusting/closing nut, and a spring therebetween, wherein the adjusting/closing nut is formed from a material having a softening/melting temperature lower than the housing and includes a portion that is locally plasticized or melted, and resolidified in form-locking engagement with the housing.

2. A rack-and-pinion gear mechanism in clam 1 , wherein the adjusting/closing nut is composed of plastic.

3. A rack-and-pinion gear mechanism in claim 1 , wherein the resolidified portion of the adjusting/closing nut engages at least one recess formed in the housing.

4. A rack-and-pinion gear in claim 1 , wherein the adjusting/locking nut comprises a plurality of resolidified portions that engage recesses due to surface roughness of the housing and form a micro form-locking connection.

5. A rack-and-pinion gear mechanism in claim 1 , wherein the adjusting/closing nut comprises a circular disc having a center axis, a first end face facing outwardly, a second end face facing the thrust piece, and a circumferential outer surface.

6. A rack-and-pinion gear mechanism in claim 5 , wherein the spring is a helical spring, and the adjusting/closing nut includes a stepped recess in said second end face, such that an end of the helical spring is received in the stepped recess.

7. A rack-and-pinion gear mechanism in claim 6 , wherein the second end face comprises a projection extending within the helical spring, and further comprises an annular channel in which the spring is seated.

8. A rack-and-pinion gear mechanism in claim 5 , wherein the adjusting/closing nut comprises a projection extending from the first end face, said projection comprising an annular step formed in parallel at a distance from the first end face and extending with a reduced diameter away from the first end face to end in a ring surface.

9. A rack-and-pinion gear mechanism in claim 8 , wherein the projection comprises a stepped blind recess extending centrally within the projection.

10. A rack-and-pinion gear mechanism in claim 9 , wherein the stepped blind recess is a multi-sided recess, allowing the adjusting/closing nut to be screwed into a threaded opening in the housing by using a matching wrench.

11. A rack-and-pinion gear mechanism in claim 5 , wherein the projection comprises outer circumferential wrench application surfaces, allowing the adjusting/closing nut to be screwed into a threaded opening in the housing by using a matching wrench.

12. A rack-and-pinion gear mechanism in claim 11 , wherein the adjusting/closing nut is screwed into a threaded opening in the housing, there being at least one radial recess distributed over the inner circumference of the opening.

13. A rack-and-pinion gear mechanism in claim 1 , wherein a clearance is provided between the adjusting/closing nut and the thrust piece.

14. A rack-and-pinion gear mechanism in claim 1 , wherein the resolidified portion prevents dislodgement of the adjusting/closing nut.

15. A method for the production of a rack-and-pinion gear mechanism comprising a pinion shaft and a rack mounted in a housing and further comprising a counter-pressure device mounted in the housing; said counter-pressure device comprising an adjusting/locking nut, a thrust piece and a spring therebetween, said method comprising:

providing an adjusting/closing nut formed from a material having a softening/melting temperature lower than the housing;

securing the adjusting/closing nut in the housing;

locally heating a portion of the adjusting/closing nut to melt or plasticize the material, whereupon the material flows into form positive contact within at least one recess in the housing; and

resolidifying the material within said recess to produce a form-locking engagement between the adjusting/closing nut and the housing.

16. A method as claimed in claim 15 , wherein the portion of the adjusting/locking nut is heated by ultrasound using a sonotrode, and is deformed with an end of the sonotrode into said form positive contact.

17. A method as claimed in claim 15 , wherein after softening or melting, the material is deformed by exertion of a mechanical pressure.

18. A method as in claim 15 , wherein the adjusting/locking nut is secured to adjust the spring to provide a clearance between the adjusting/locking nut and the thrust piece, and wherein the adjusting/locking nut is locally heated and resolidified without altering the clearance.

19. A method for the production of a rack-and-pinion gear mechanism comprising a pinion shaft and a rack mounted in a housing and further comprising a counter-pressure device mounted in the housing; said counter-pressure device comprising an adjusting/locking nut, a thrust piece and a spring therebetween, said method comprising:

providing an adjusting/closing nut formed from a material having a softening/melting temperature lower than the housing;

securing the adjusting/closing nut in the housing;

locally heating a portion of the adjusting/closing nut to melt or plasticize the material, whereupon the material flows into form positive contact within at least one recess in the housing;

exerting a mechanical pressure onto the material after the material has been melted or plasticized; and

resolidifying the material within said recess to produce a form-locking engagement between the adjusting/closing nut and the housing.

20. A method as claimed in claim 19 , wherein the portion of the adjusting/locking nut is heated by ultrasound using a sonotrode, and is deformed with an end of the sonotrode into said form positive contact.

21. A method as in claim 19 , wherein the adjusting/locking nut is secured to adjust the spring to provide a clearance between the adjusting/locking nut and the thrust piece, and wherein the adjusting/locking nut is locally heated and resolidified without altering the clearance.