SYSTEM, METHOD AND APPARATUS FOR TOLERANCE RING CONTROL OF SLIP INTERFACE SLIDING FORCES
A tolerance ring comprising a metallic band for spring features and a complementary low friction material for frictional considerations is disclosed. The tolerance ring is designed to operate within a precisely controlled torque or axial force band to provide a defined amount of resistance and sliding force control between components that move relative to each other. Isolated portions of the tolerance ring form regions of contact with adjacent ones of the components. Other surfaces of the tolerance ring comprise portions with spring features that have geometry suitable for their spring rate, rather than conforming to mating surfaces of the adjacent components.
1 . A tolerance ring, comprising:
a metallic material and a low friction material attached thereto, wherein the tolerance ring is adapted to provide:
a radial stiffness that is greater than about 20,000 N/mm; and
a slip torque in a range of about 1 to about 25 Nm.
2 . The tolerance ring according to claim 1 , wherein the tolerance ring comprises a generally annular band.
3 . The tolerance ring according to claim 2 , wherein the annular band has a radial thickness of about 0.1 to about 0.7 mm, and the low friction material has a radial thickness in a range of about 0.05 to about 0.50 mm.
4 . The tolerance ring according to claim 1 , wherein the tolerance ring further comprises a gap.
5 . The tolerance ring according to claim 1 , wherein the metallic material comprises spring steel, and wherein the low friction material has a coefficient of friction in a range of about 0.04 to about 0.25.
6 . The tolerance ring according to claim 1 , wherein the low friction material comprises a polymer.
7 . The tolerance ring according to claim 6 , wherein the low friction material comprises PTFE.
8 . The tolerance ring according to claim 1 , wherein the tolerance ring includes a plurality of projections extending in a radial direction.
9 . The tolerance ring according to claim 8 , wherein the projections extend in an axial direction as axially-elongated ridges, and wherein the tolerance ring further comprises circumferentially-extending rims at axial ends of the projections.
10 . The tolerance ring according to claim 8 , wherein the projections are circumferentially spaced apart from each other.
11 . The tolerance ring according to claim 10 , wherein the low friction material is laminated onto the metallic material adjacent to the protrusions and the sections between the protrusions.
12 . The tolerance ring according to claim 8 , wherein the projections circumferentially abut one another.
13 . An assembly, comprising:
an outer component;
an inner component located in the outer component and movable relative thereto;
a tolerance ring mounted between the inner and outer components, the tolerance ring providing:
a radial stiffness that is greater than about 20,000 N/mm; and
parameters selected from the group consisting of:
(i) a slip torque in a range of about 1 to about 25 Nm, and a diameter of less than about 40 mm;
(ii) a slip torque in a range of about 1 to about 100 Nm, and a diameter of more than about 40 mm; and
(iii) an axial sliding force in a range of about 10 to about 600 N, and a diameter of more than about 10 mm.
14 . The assembly according to claim 13 , wherein the tolerance ring comprises an annular band formed from a metallic material and a low friction material.
15 . The assembly according to claim 14 , wherein the annular band is formed from spring steel, and wherein the low friction material has a coefficient of friction in a range of about 0.04 to about 0.25.
16 . The assembly according to claim 14 , wherein the annular band has a radial thickness of about 0.1 to about 0.7 mm, and wherein the low friction material has a radial thickness in a range of about 0.05 to about 0.50 mm.
17 . The assembly according to claim 13 , wherein the tolerance ring has a plurality of projections extending in a radial direction.
18 . The assembly according to claim 17 , wherein the projections extend in an axial direction as axially-elongated ridges and are circumferentially spaced apart from each other.
19 . The assembly according to claim 17 , wherein the tolerance ring further comprises circumferentially-extending rims at axial ends of the projections.
20 . An assembly, comprising:
an outer component;
an inner component located in the outer component and movable relative thereto;
a tolerance ring mounted between the inner and outer components, wherein the tolerance ring comprises a metallic material having a thickness t m and a low friction material having a thickness t l , wherein a ratio of t m /t l >1, and wherein the tolerance ring provides:
a radial stiffness that is greater than about 20,000 N/mm; and
parameters selected from the group consisting of:
(i) a slip torque in a range of about 1 to about 25 Nm, and a diameter of less than about 40 mm;
(ii) a slip torque in a range of about 1 to about 100 Nm, and a diameter of more than about 40 mm; and
(iii) an axial sliding force in a range of about 10 to about 600 N, and a diameter of more than about 10 mm.