Power steering system for motor vehicles
For a power steering system which has, as a recirculating ball steering, a worm shaft and, enclosing this, a working plunger which is to be actuated by a bead chain axially shiftably with respect to the worm shaft, an axial seal is provided for the annular gap between the working plunger and the worm shaft which has a multi-part arrangement, and which has two support rings and one sealing ring, engaging between the support rings, pointing in opposite directions and guided in an annular grove of the working plunger, the width of the annular groove being greater than the axial width of the axial seal at the support rings arranged adjacent to the sealing ring.
1. A power steering system for a motor vehicle, comprising:
a housing;
a driven worm shaft arranged in the housing;
a bead chain;
a working plunger arranged in the housing coaxial to the worm shaft and arranged axially shiftably braced against the worm shaft via the bead chain, the working plunger arranged to have pressure applied thereto at both ends;
a ring seal; and
an annular gap extending between the worm shaft and the working plunger in a transition from pressure chambers separated by the working plunger to the ring seal guided in an annular groove and covering the annular gap;
wherein the ring seal is arranged as a multi-part axial seal including two gap-covering support rings braced shiftably against groove flanks and axially spaced apart from each other and a sealing ring braced axially shiftably against a groove base and between the support rings, the support rings having a triangular cross-section, the sealing ring having the form of a wedge.
2. The power steering system according to claim 1 , wherein the sealing ring has a substantially isosceles triangular cross-section.
3. The power steering system according to claim 2 , wherein the sealing ring has substantially equal-sided trapezium cross-section.
4. The power steering system according to claim 1 , wherein cross-sections of the support rings are equal.
5. The power steering system according to claim 1 , wherein the support rings have a substantially right-angle triangular cross-section.
6. The power steering system according to claim 1 , wherein the support rings are made of plastic.
7. The power steering system according to claim 1 , wherein the support rings are made of polyamide.
8. The power steering system according to claim 1 , wherein the sealing ring is made of plastic.
9. The power steering system according to claim 1 , wherein the sealing ring is made of polytetrafluoroethylene.
10. The power steering system according to claim 1 , wherein the sealing ring is made of fiber-reinforced polytetrafluoroethylene.
11. The power steering system according to claim 1 , wherein the support rings are made of a material more rigid to pressure than a material of the sealing ring.