TOLERANCE RING WITH MODIFIED SURFACE PROPERTIES

Systems and methods include providing a tolerance ring with a friction enhancement feature on at least one surface of the tolerance ring to increase at least one friction-related property of the tolerance ring. The friction enhancement feature provides the tolerance ring with an increased retention force while providing an optimum radial force that allows a component secured by the tolerance ring to move freely while reducing or altogether preventing axial movement of the component.

BACKGROUND OF THE INVENTION

Tolerance rings are commonly used between hardware components in a wide variety of industries. Some tolerance ring applications require the tolerance ring to retain a component, such as a bearing, within a housing or other hardware component while allowing free movement of the component. However, axial forces required for the proper retention of the component within the housing or other hardware component may impart undesirable axial forces on the component, which may restrict the free movement of the component. Accordingly, the industry continues to demand improvements in tolerance ring technology for such applications.

DETAILED DESCRIPTION

FIG.1is a cross-sectional view of a tolerance ring100according to an embodiment of the disclosure. The tolerance ring100may generally comprise a band of material or a substrate102formed into an annular ring shape. In some embodiments, the tolerance ring100may comprise a gap104defining a first circumferential end106and a second circumferential end108of the substrate102. In some embodiments, the substrate102may be formed from a resilient metallic material. In some embodiments, the metallic material may comprise aluminum, beryllium, bronze, copper, iron, magnesium, steel, spring steel, stainless steel, tin, titanium, tungsten, or an alloy thereof.

The tolerance ring100may comprise a plurality of protrusions110(e.g., fingers, waves, etc.) formed in the substrate102. In some embodiments, the protrusions110may protrude radially inward from an inner surface112or radially outward from an outer surface114of the substrate100. In some embodiments, the protrusions110may be disposed circumferentially about the substrate102. In some embodiments, the protrusions110may comprise the same geometric shape and/or size as compared to each other. In other embodiments, a number of protrusions110may have different geometric shapes and/or sizes as compared to each other. In yet other embodiments, all of the protrusions110may have different geometric shapes and/or sizes as compared to each other. It will be appreciated that the protrusions100may be selected to provide desired elastic/plastic deformation characteristics, desired force transfer properties, and/or to account for manufacturing tolerances of hardware components, and/or to compensate for thermal expansion and wear that may occur between hardware components during operation.

The tolerance ring100may also comprise a friction enhancement feature116. In some embodiments, the friction enhancement feature116may be applied to the inner surface112and/or the outer surface114of the substrate102. In some embodiments, the friction enhancement feature116may comprise a coating. In some embodiments, the coating may comprise a polymer coating, such as an elastomer-based polymer, a resin-based polymer, rubber, or a combination thereof. In some embodiments, the coating may comprise a ceramic coating. In some embodiments, the coating may comprise a metal, such as a metal powder-filled resin coating. In some embodiments, the coating may comprise an adhesive, such as a methacrylate-based adhesive. In some embodiments, the coating may comprise a single layer. In other embodiments, the coating may comprise a plurality of layers. In such embodiments, the plurality of layers may comprise a first retention layer and a second friction enhancing layer.

In some embodiments, the coating may be applied to the inner surface112of the substrate102, the outer surface114of the substrate102, or a combination thereof. Further, in some embodiments, the coating may be applied over the protrusions110. In some embodiments, the coating may comprise a thickness of at least 0.001 mm (1 micron), at least 0.01 mm (10 microns), at least 0.02 mm (20 microns), at least 0.03 mm (30 microns), at least 0.04 mm (40 microns), or at least 0.05 mm (50 microns). In some embodiments, the coating may comprise a thickness of not greater than 0.50 mm (500 microns), not greater than 0.25 mm (250 microns), not greater than 0.20 mm (200 microns), not greater than 0.15 mm (150 microns), or not greater than 0.10 mm (100 microns). Further, it will be appreciated that the coating may comprise a thickness between any of these minimum and maximum values, such as at least 0.01 mm (10 microns) to not greater than 0.50 mm (500 microns).

In some embodiments, the friction enhancement feature116may comprise a cladding. In some embodiments, the cladding may comprise aluminum, brass, bronze, copper, magnesium, zinc, an alloy thereof, an oxide-free corrosion-resistant metallic material, or any combination thereof. In some embodiments, the cladding may comprise a single layer. In other embodiments, the cladding may comprise a plurality of layers. In such embodiments, the plurality of layers may comprise a first retention layer and a second friction enhancing layer. In some embodiments, the cladding may be applied to the inner surface112of the substrate102, the outer surface114of the substrate102, or a combination thereof. Further, in some embodiments, the cladding may be applied over the protrusions110.

In some embodiments, the cladding may comprise a thickness of at least 0.01 mm (10 microns), at least 0.02 mm (20 microns), at least 0.03 mm (30 microns), at least 0.04 mm (40 microns), or at least 0.05 mm (50 microns). In some embodiments, the cladding may comprise a thickness of not greater than 0.50 mm (500 microns), not greater than 0.25 mm (250 microns), not greater than 0.20 mm (200 microns), not greater than 0.15 mm (150 microns), or not greater than 0.10 mm (100 microns). Further, it will be appreciated that the cladding may comprise a thickness between any of these minimum and maximum values, such as at least 0.01 mm (10 microns) to not greater than 0.50 mm (500 microns).

In some embodiments, the friction enhancement feature116may comprise a surface treatment. In some embodiments, the surface treatment may comprise a mechanical surface treatment, such as shot peening, sand blasting, or a combination thereof. In some embodiments, the surface treatment may be applied to the inner surface112of the substrate102, the outer surface114of the substrate102, or a combination thereof. Further, in some embodiments, the surface treatment may be applied over the protrusions110. In some embodiments, the surface treatment may be applied over at least 5%, at least 10%, at least 25%, at least 50%, at least 75%, at least 80%, at least 85%, or at least 90% of the substrate102. In some embodiments, the surface treatment may be applied over not greater than 95%, not greater than 90%, not greater than 85%, not greater than 80%, not greater than 75%, or not greater than 50% of the substrate102. Further, it will be appreciated that the surface treatment may be applied over the substrate102between any of these minimum and maximum values, such as at least 5% to not greater than 95% of the substrate102.

In some embodiments, the friction enhancement feature116may be configured to increase at least one performance property of the tolerance ring100. In some embodiments, the friction enhancement feature116may be configured to increase at least one friction-related property of the tolerance ring100. In some embodiments, the friction enhancement feature116may be configured to increase a coefficient of friction of the tolerance ring100. In some embodiments, the friction enhancement feature116may be configured to increase the coefficient of friction of the tolerance ring100by at least 1%, at least 2%, at least 3%, at least 4%, at least 5%, at least 10%, at least 15%, at least 20%, at least 25%, at least 30%, at least 35%, at least 40%, or at least 50%. In some embodiments, the friction enhancement feature116may be configured to increase the coefficient of friction of the tolerance ring100by not greater than 1000%, not greater than 500%, not greater than 200%, not greater than 100%, not greater than 75%, or not greater than 50%. Further, it will be appreciated that the friction enhancement feature116may be configured to increase the coefficient of friction of the tolerance ring100between any of these minimum and maximum values, such as at least 1% to not greater than 500%.

In some embodiments, the friction enhancement feature116may be configured to provide the tolerance ring100with a coefficient of friction of at least 0.15, at least 0.20, at least 0.25, at least 0.3, at least 0.35, at least 0.40, at least 0.45, at least 0.50, at least 0.55, or at least 0.60. In some embodiments, the friction enhancement feature116may be configured to provide the tolerance ring100with a coefficient of friction of not greater than 0.95, not greater than 0.90, not greater than 0.85, not greater than 0.80, not greater than 0.75, not greater than 0.70, not greater than 0.65, not greater than 0.60, not greater than 0.55, not greater than 0.50, not greater than 0.45, or not greater than 0.40. Further, it will be appreciated that the friction enhancement feature116may be configured to provide the tolerance ring100with a coefficient of friction between any of these minimum and maximum values, such as at least 0.15 to not greater than 0.95. In the above-referenced embodiments, it will be further appreciated that the coefficient of friction of the tolerance ring10may be measured against aluminum, steel, or stainless steel.

In some embodiments, the friction enhancement feature116may be configured to increase a retention force of the tolerance ring100. In some embodiments, the friction enhancement feature116may be configured to increase the retention force of the tolerance ring100by at least 1%, at least 2%, at least 3%, at least 4%, at least 5%, at least 10%, at least 15%, at least 20%, at least 25%, at least 30%, at least 35%, at least 40%, or at least 50% for a given assembly force. In some embodiments, the friction enhancement feature116may be configured to increase the retention force of the tolerance ring by not greater than 500%, not greater than 200%, not greater than 100%, not greater than 75%, or not greater than 50% for a given assembly force. Further, it will be appreciated that the friction enhancement feature116may be configured to increase the retention force of the tolerance ring100between any of these minimum and maximum values, such as at least 1% to not greater than 500%.

In some embodiments, the friction enhancement feature116may be configured to provide the tolerance ring100with a retention force of at least 150 N, at least 250 N, at least 500 N, at least 1000 N, at least 1500 N, at least 2000 N, at least 2250 N, at least 2300 N, at least 2350 N, at least 2400 N, at least 2450 N, at least 2500 N, at least 2550 N, at least 2600 N, at least 2650 N, at least 2700 N, at least 2750 N, at least 2800 N, at least 2850 N, at least 2900 N, at least 2950 N, at least 3000 N, at least 3050 N, at least 3100 N, at least 3150 N, at least 3200 N, at least 3250 N, at least 3300 N, at least 3350 N, at least 3400 N, at least 3450 N, or at least 3500 N. In some embodiments, the friction enhancement feature116may be configured to provide the tolerance ring100with a retention force of not greater than 6000 N, not greater than 5750 N, not greater than 5500 N, not greater than 5250 N, not greater than 5000 N, not greater than 4750 N, not greater than 4500 N, not greater than 4250 N, not greater than 4000 N, not greater than 3750 N, not greater than 3500 N, not greater than 3250 N, not greater than 3000 N, not greater than 2950 N, not greater than 2900 N, not greater than 2850 N, not greater than 2800 N, not greater than 2750 N, not greater than 2700 N, not greater than 2650 N, not greater than 2600 N, not greater than 2550 N, or not greater than 2500 N. Further, it will be appreciated that the friction enhancement feature116may be configured to provide the tolerance ring100with a retention force between any of these minimum and maximum values, such as at least 2250 N to not greater than 6000 N.

In some embodiments, the friction enhancement feature116may be configured to increase a surface roughness (Ra, Rz) of the tolerance ring100. In some embodiments, the friction enhancement feature116may be configured to increase the surface roughness of the tolerance ring100by at least 1%, at least 2%, at least 3%, at least 4%, at least 5%, at least 10%, at least 15%, at least 20%, at least 25%, at least 30%, at least 35%, at least 40%, or at least 50%. In some embodiments, the friction enhancement feature116may be configured to increase the surface roughness of the tolerance ring100by not greater than 500%, not greater than 200%, not greater than 100%, not greater than 75%, or not greater than 50%. Further, it will be appreciated that the friction enhancement feature116may be configured to increase the surface roughness of the tolerance ring100between any of these minimum and maximum values, such as at least 1% to not greater than 500%.

In some embodiments, the friction enhancement feature116may be configured to provide the tolerance ring100with a surface roughness (Ra) of at least 1.5, at least 2, at least 2.5, at least 3.0, at least 3.5, at least 4.0, at least 5.0, at least 5.5, or at least 6.0. In some embodiments, the friction enhancement feature116may be configured to provide the tolerance ring100with a surface roughness (Ra) of not greater than 25, not greater than 20, not greater than 19, not greater than 18, not greater than 17, not greater than 16, not greater than 15, not greater than 14, not greater than 13, not greater than 12, not greater than 11, not greater than 10, or not greater than 5. Further, it will be appreciated that the friction enhancement feature116may be configured to provide the tolerance ring100with a surface roughness (Ra) between any of these minimum and maximum values, such as at least 1.5 to not greater than 25.

In some embodiments, the friction enhancement feature116may be configured to provide the tolerance ring100with a surface roughness (Rz) of at least 5, at least 6, at least 7, at least 8, at least 9, at least 10, at least 11, at least 12, at least 13, at least 14, at least 15, at least 20, or at least 25. In some embodiments, the friction enhancement feature116may be configured to provide the tolerance ring100with a surface roughness (Rz) of not greater than 50, not greater than 35, not greater than 30, not greater than 25, not greater than 20, not greater than 19, not greater than 18, not greater than 17, not greater than 16, or not greater than 15. Further, it will be appreciated that the friction enhancement feature116may be configured to provide the tolerance ring100with a surface roughness (Rz) between any of these minimum and maximum values, such as at least 5 to not greater than 50.

In some embodiments, the friction enhancement feature116may be configured to provide the tolerance ring100with a Retention to Assembly Ratio (RAR) defined by the equation:

Retention to Assembly Ratio(RAR)=Retention Force/Peak Assembly Force

In some embodiments, disassembly retention force may be used instead of peak assembly force. In some embodiments, the friction enhancement feature116may be configured to provide the tolerance ring100with a Retention to Assembly Ratio (RAR) of at least 0.5, at least 0.51, at least 0.52, at least 0.53, at least 0.54, at least 0.55, at least 0.56, at least 0.57, at least 0.58, at least 0.59, at least 0.60, at least 0.65, at least 0.70, at least 0.75, at least 0.80, or at least 0.85. In some embodiments, the friction enhancement feature116may be configured to provide the tolerance ring100with a Retention to Assembly Ratio (RAR) of not greater than 5, not greater than 4, not greater than 3, not greater than 2, not greater than 1, not greater than 0.90, not greater than 0.89, not greater than 0.88, not greater than 0.87, not greater than 0.86, not greater than 0.85, not greater than 0.80, not greater than 0.75, not greater than 0.70, or not greater than 0.65. Further, it will be appreciated that the friction enhancement feature116may be configured to provide the tolerance ring100with a Retention to Assembly Ratio (RAR) between any of these minimum and maximum values, such as at least 0.5 to not greater than 0.90.

In some embodiments, the retention force of the tolerance ring100may have a variance based on temperature. In some embodiments, the retention force of the tolerance ring100have a variance of at least 1%, at least 2%, at least 3%, at least 4%, at least 5%, at least 6%, at least 7%, at least 8%, at least 9%, at least 10%, at least 15%, at least 20%, or at least 25% higher or lower based on the temperature range of between −40° C. and 200° C., such as between −20° C. and 150° C., such as between −10° C. and 120° C., such as between 0° C. and 100° C., or such as between 25° C. and 75° C. Further, it will be appreciated that the retention force of the tolerance ring100may be between any of these minimum and maximum values, such as at least 1% to not greater than 100%.

FIG.2Ashows a cross-sectional view of an assembly200comprising a tolerance ring100according to an embodiment of the disclosure.FIG.2Bshows a top view of an assembly200comprising a tolerance ring100according to an embodiment of the disclosure. The assembly100may generally comprise an outer component202and an inner component204. In some embodiments, the outer component202may comprise a housing. In some embodiments, the outer component202may be formed from aluminum, steel, stainless steel, or titanium. In some embodiments, the inner component204may be a component, such as a bearing. In some embodiments, the inner component204may be formed from aluminum, steel, stainless steel, or titanium. The tolerance ring100may generally be disposed within the outer component202and configured to retain or secure the inner component204within the outer component202.

Furthermore, as described herein, the tolerance ring100may comprise a friction enhancement feature116that increases a coefficient of friction between the tolerance ring100and the outer component202and/or the inner component204, increases a peak assembly force to install and/or remove the tolerance ring100from the outer component202, increases a retention force applied by the tolerance ring100on the inner component204to retain or secure the inner component204within the outer component202, and/or increases a surface roughness (Ra, Rz) of the tolerance ring100. The increase in the aforementioned values may be compared to a traditional tolerance ring that does not include a friction enhancement feature116. Further, in some embodiments, the friction enhancement feature116may provide the tolerance ring100with an increased retention force while providing an optimum radial force that allows the inner component204secured by the tolerance ring100to move freely while reducing or altogether preventing axial movement of the inner component204.

FIG.3is a flowchart of a method300of forming a tolerance ring100according to an embodiment of the disclosure. The method300may begin at block302by providing a substantially flat substrate102formed from a metallic material. The method300may continue at block304by applying a friction enhancement feature116to at least one of an inner surface112and an outer surface114of the substrate102. The method300may continue at block306by forming a plurality of protrusions110in the substrate102that protrude radially inward from the inner surface112of the substrate102or radially outward from the outer surface114of the substrate102. In some embodiments, it will be appreciated that the method300may include forming the plurality of protrusions110at block306prior to applying the friction enhancement feature116to the substrate102at block304. The method may continue at block308by forming the substrate102into an annular ring-shaped tolerance ring100.

Examples

A standard tolerance ring, C1, and two exemplary embodiments, S1 and S2, of a tolerance ring100were created. Each of C1, S1, and S2 were created from a stainless steel substrate102and included a plurality of protrusions116formed in the substrate102. C1 did not include any friction enhancement features116. S1 included a friction enhancement feature116comprising at least one aluminum outer layer overlying the inner diameter and the outer diameter of the substrate102. S2 included a friction enhancement feature116comprising a high temperature coating based on a modified polyester resin, such as Thermodur 600, disposed over the substrate102. C1, S1, and S2 were placed in identical aluminum housings, and a bearing was installed in each of the assemblies. The maximum assembly force and the remaining assembly force were measured during assembly. Table 1 shows the maximum assembly force and the remaining assembly force for a 0.905 mm clearance (ID 23.810 mm). Table 2 shows the maximum assembly force and the remaining assembly force for a 0.9705 mm clearance (ID 23.941 mm).

Additional samples were created of each of C1, S1, and S2. Table 3 shows the average assembled torque, remaining assembly force, retention force, and Retention to Assembly Ratio (RAR) for the total number of samples.

Additional samples were created of each of C1, S1, and S2. The samples were tested at heated and non-heated conditions. Table 4 shows a comparison of the retention force when non-heated and when heated for the total number of samples. Notably, the retention force of C1 decreased when heated, while the retention force of S1 and S2 increased when heated.

Embodiments of a tolerance ring100, an assembly200, and/or a method300of forming a tolerance ring100may include one or more of the following:

Embodiment 1: A tolerance ring, comprising: an annular ring-shaped substrate formed from a metallic material and comprising a plurality of protrusions protruding radially inward from an inner surface of the substrate or radially outward from an outer surface of the substrate; and a friction enhancement feature applied to at least one of the inner surface and the outer surface of the substrate.

Embodiment 2: The tolerance ring of embodiment 1, wherein the metallic material of the substrate comprises steel, spring steel, or stainless steel.

Embodiment 3: The tolerance ring of any one of embodiments 1 to 2, wherein the friction enhancement feature comprises a coating, a cladding, a surface treatment, or a combination thereof.

Embodiment 4: The tolerance ring of embodiment 3, wherein the coating comprises a polymer coating.

Embodiment 5: The tolerance ring of embodiment 4, wherein the polymer coating comprises an elastomer-based polymer, a resin-based polymer, rubber, or a combination thereof.

Embodiment 6: The tolerance ring of embodiment 3, wherein the coating comprises a ceramic coating.

Embodiment 7: The tolerance ring of embodiment 3, wherein the coating comprises a metal.

Embodiment 8: The tolerance ring of embodiment 7, wherein the metal comprises a metal powder-filled resin coating.

Embodiment 9: The tolerance ring of embodiment 3, wherein the coating comprises an adhesive.

Embodiment 10: The tolerance ring of embodiment 9, wherein the adhesive comprises a methacrylate-based adhesive.

Embodiment 11: The tolerance ring of any one of embodiments 3 to 10, wherein the coating comprises a plurality of layers.

Embodiment 12: The tolerance ring of embodiment 11, wherein the plurality of layers comprises a first retention layer and a second friction enhancing layer.

Embodiment 13: The tolerance ring of any one of embodiments 3 to 12, wherein the coating is applied to the inner surface of the substrate, the outer surface of the substrate, or a combination thereof.

Embodiment 14: The tolerance ring of embodiment 13, wherein the coating is applied over the protrusions.

Embodiment 15: The tolerance ring of any one of embodiments 3 to 14, wherein the coating comprises a thickness of at least 0.001 mm (1 micron), at least 0.01 mm (10 microns), at least 0.02 mm (20 microns), at least 0.03 mm (30 microns), at least 0.04 mm (40 microns), or at least 0.05 mm (50 microns).

Embodiment 16: The tolerance ring of embodiment 15, wherein the coating comprises a thickness of not greater than 0.50 mm (500 microns), not greater than 0.25 mm (250 microns), not greater than 0.20 mm (200 microns), not greater than 0.15 mm (150 microns), or not greater than 0.10 mm (100 microns).

Embodiment 18: The tolerance ring of any one of embodiments 3 and 17, wherein the cladding comprises a plurality of layers.

Embodiment 19: The tolerance ring of embodiment 18, wherein the plurality of layers comprises a first retention layer and a second friction enhancing layer.

Embodiment 20: The tolerance ring of any one of embodiments 3 and 17 to 19, wherein the cladding is applied to the inner surface of the substrate, the outer surface of the substrate, or a combination thereof.

Embodiment 21: The tolerance ring of embodiment 20, wherein the cladding is applied over the protrusions.

Embodiment 22: The tolerance ring of any one of embodiments 3 and 17 to 21, wherein the cladding comprises a thickness of at least 0.01 mm (10 microns), at least 0.02 mm (20 microns), at least 0.03 mm (30 microns), at least 0.04 mm (40 microns), or at least 0.05 mm (50 microns).

Embodiment 23: The tolerance ring of embodiment 22, wherein the cladding comprises a thickness of not greater than 0.50 mm (500 microns), not greater than 0.25 mm (250 microns), not greater than 0.20 mm (200 microns), not greater than 0.15 mm (150 microns), or not greater than 0.10 mm (100 microns).

Embodiment 24: The tolerance ring of embodiment 3, wherein the surface treatment comprises a mechanical surface treatment.

Embodiment 25: The tolerance ring of embodiment 24, wherein the mechanical surface treatment comprises shot peening, sand blasting, or a combination thereof.

Embodiment 26: The tolerance ring of any one of embodiments 3 and 24 to 25, wherein the surface treatment is applied to the inner surface of the substrate, the outer surface of the substrate, or a combination thereof.

Embodiment 27: The tolerance ring of embodiment 26, wherein the surface treatment is applied over the protrusions.

Embodiment 28: The tolerance ring of any one of embodiments 1 to 27, wherein the friction enhancement feature is configured to increase at least one performance property of the tolerance ring.

Embodiment 29: The tolerance ring of any one of embodiments 1 to 28, wherein the friction enhancement feature is configured to increase at least one friction-related property of the tolerance ring.

Embodiment 30: The tolerance ring of embodiment 29, wherein the friction enhancement feature is configured to increase a coefficient of friction of the tolerance ring.

Embodiment 31: The tolerance ring of embodiment 30, wherein the friction enhancement feature is configured to increase a coefficient of friction of the tolerance ring by at least 1%, at least 2%, at least 3%, at least 4%, at least 5%, at least 10%, at least 15%, at least 20%, at least 25%, at least 30%, at least 35%, at least 40%, or at least 50%.

Embodiment 32: The tolerance ring of embodiment 31, wherein the friction enhancement feature is configured to increase a coefficient of friction of the tolerance ring by not greater than 1000%, not greater than 500%, not greater than 200%, not greater than 100%, not greater than 75%, or not greater than 50%.

Embodiment 33: The tolerance ring of any one of embodiments 29 to 32, wherein the friction enhancement feature is configured to provide the tolerance ring with a coefficient of friction of at least 0.15, at least 0.20, at least 0.25, at least 0.3, at least 0.35, at least 0.40, at least 0.45, at least 0.50, at least 0.55, or at least 0.60.

Embodiment 34: The tolerance ring of embodiment 33, wherein the friction enhancement feature is configured to provide the tolerance ring with a coefficient of friction of not greater than 0.95, not greater than 0.90, not greater than 0.85, not greater than 0.80, not greater than 0.75, not greater than 0.70, not greater than 0.65, not greater than 0.60, not greater than 0.55, not greater than 0.50, not greater than 0.45, or not greater than 0.40.

Embodiment 35: The tolerance ring of any one of embodiments 33 to 34, wherein the coefficient of friction of the tolerance ring is measured against aluminum, steel, or stainless steel.

Embodiment 36: The tolerance ring of any one of embodiments 29 to 35, wherein the friction enhancement feature is configured to increase a retention force of the tolerance ring.

Embodiment 37: The tolerance ring of embodiment 36, wherein the friction enhancement feature is configured to increase a retention force of the tolerance ring by at least 1%, at least 2%, at least 3%, at least 4%, at least 5%, at least 10%, at least 15%, at least 20%, at least 25%, at least 30%, at least 35%, at least 40%, or at least 50% for a given assembly force.

Embodiment 38: The tolerance ring of embodiment 37, wherein the friction enhancement feature is configured to increase a retention force of the tolerance ring by not greater than 500%, not greater than 200%, not greater than 100%, not greater than 75%, or not greater than 50% for a given assembly force.

Embodiment 39: The tolerance ring of any one of embodiments 29 to 38, wherein the friction enhancement feature is configured to provide the tolerance ring with a retention force of at least 150 N, at least 250 N, at least 500 N, at least 1000 N, at least 1500 N, at least 2000 N, at least 2250 N, at least 2500 N, at least 2600 N, at least 2650 N, at least 2700 N, at least 2750 N, at least 2800 N, at least 2850 N, at least 2900 N, at least 2950 N, at least 3000 N, at least 3050 N, at least 3100 N, at least 3150 N, at least 3200 N, at least 3250 N, at least 3300 N, at least 3350 N, at least 3400 N, at least 3450 N, or at least 3500 N.

Embodiment 40: The tolerance ring of embodiment 39, wherein the friction enhancement feature is configured to provide the tolerance ring with a retention force of not greater than 6000 N, not greater than 5750 N, not greater than 5500 N, not greater than 5250 N, not greater than 5000 N, not greater than 4750 N, not greater than 4500 N, not greater than 4250 N, not greater than 4000 N, not greater than 3750 N, not greater than 3500 N, not greater than 3250 N, not greater than 3000 N, not greater than 2950 N, not greater than 2900 N, not greater than 2850 N, not greater than 2800 N, not greater than 2750 N, not greater than 2700 N, not greater than 2650 N, not greater than 2600 N, not greater than 2550 N, or not greater than 2500 N.

Embodiment 41: The tolerance ring of any one of embodiments 29 to 40, wherein the friction enhancement feature is configured to increase a surface roughness of the tolerance ring.

Embodiment 42: The tolerance ring of embodiment 41, wherein the friction enhancement feature is configured to increase a surface roughness of the tolerance ring by at least 1%, at least 2%, at least 3%, at least 4%, at least 5%, at least 10%, at least 15%, at least 20%, at least 25%, at least 30%, at least 35%, at least 40%, or at least 50%.

Embodiment 43: The tolerance ring of embodiment 42, wherein the friction enhancement feature is configured to increase a surface roughness of the tolerance ring by not greater than 500%, not greater than 200%, not greater than 100%, not greater than 75%, or not greater than 50%.

Embodiment 44: The tolerance ring of any one of embodiments 29 to 43, wherein the friction enhancement feature is configured to provide the tolerance ring with a surface roughness (Ra) of at least 1.5, at least 2, at least 2.5, at least 3.0, at least 3.5, at least 4.0, at least 5.0, at least 5.5, or at least 6.0.

Embodiment 45: The tolerance ring of embodiment 44, wherein the friction enhancement feature is configured to provide the tolerance ring with a surface roughness (Ra) of not greater than 25, not greater than 20, not greater than 19, not greater than 18, not greater than 17, not greater than 16, not greater than 15, not greater than 14, not greater than 13, not greater than 12, not greater than 11, not greater than 10, or not greater than 5.

Embodiment 46: The tolerance ring of any one of embodiments 29 to 45, wherein the friction enhancement feature is configured to provide the tolerance ring with a surface roughness (Rz) of at least 5, at least 6, at least 7, at least 8, at least 9, at least 10, at least 11, at least 12, at least 13, at least 14, at least 15, at least 20, or at least 25.

Embodiment 47: The tolerance ring of embodiment 46, wherein the friction enhancement feature is configured to provide the tolerance ring with a surface roughness (Rz) of not greater than 50, not greater than 35, not greater than 30, not greater than 25, not greater than 20, not greater than 19, not greater than 18, not greater than 17, not greater than 16, or not greater than 15.

Embodiment 48: The tolerance ring of any one of embodiments 1 to 47, wherein the tolerance ring comprises a Retention to Assembly Ratio (RAR) of at least 0.5, at least 0.51, at least 0.52, at least 0.53, at least 0.54, at least 0.55, at least 0.56, at least 0.57, at least 0.58, at least 0.59, at least 0.60, at least 0.65, at least 0.70, at least 0.75, at least 0.80, or at least 0.85.

Embodiment 49: The tolerance ring of any one of embodiments 1 to 47, wherein the tolerance ring comprises a Retention to Assembly Ratio (RAR) of not greater than 5, not greater than 4, not greater than 3, not greater than 2, not greater than 1, not greater than 0.90, not greater than 0.89, not greater than 0.88, not greater than 0.87, not greater than 0.86, not greater than 0.85, not greater than 0.80, not greater than 0.75, not greater than 0.70, or not greater than 0.65.

Embodiment 50: The tolerance ring of any one of embodiments 1 to 49, wherein the retention force of the tolerance ring has a variance of +/−5% between a temperature range of −40° C. to 200° C.

Embodiment 51: The tolerance ring of any one of embodiments 1 to 49, wherein the retention force of the tolerance ring has a variance of +/−10% between a temperature range of −40° C. to 200° C.

Embodiment 52: The tolerance ring of embodiment 51, wherein the retention force of the tolerance ring has a variance of +/−15% between a temperature range of −40° C. to 200° C.

Embodiment 53: The tolerance ring of any one of embodiments 51 to 52, wherein the retention force of the tolerance ring has a variance of +/−25% between a temperature range of −40° C. to 200° C.

Embodiment 54: An assembly, comprising: an outer component comprising a housing; an inner component comprising a component; and a tolerance ring according to any of the preceding embodiments, wherein the tolerance ring is disposed within the housing and configured to retain or secure the component within the housing.

Embodiment 55: The assembly of embodiment 54, wherein the housing is formed from aluminum, steel, stainless steel, or titanium.

Embodiment 56: The assembly of any one of embodiments 54 to 55, wherein the component is formed from aluminum, steel, stainless steel, or titanium.

Embodiment 57: The assembly of embodiment 54, wherein the component comprises a bearing.

Embodiment 58: A method of forming a tolerance ring according to any of the preceding embodiments, comprising: providing a substantially flat substrate formed from a metallic material; applying a friction enhancement feature to at least one of an inner surface and an outer surface of the substrate; forming a plurality of protrusions in the substrate that protrude radially inward from the inner surface of the substrate or radially outward from the outer surface of the substrate; and forming the substrate into an annular ring-shaped tolerance ring.