Bearing interface arrangement with local and controlled thermal expansion

Abstract

A bearing interface assembly configured to accommodate different thermal expansion rates of a bearing and a housing of an installation location. The bearing interface assembly includes a metal sleeve having an outer surface defining a groove and an inner surface defining an opening configured to engage the bearing, the metal sleeve configured to expand at a first coefficient of thermal expansion; and a filament-wound composite wrap seated within the groove of the metal sleeve, the filament-wound composite wrap configured to expand at a second coefficient of thermal expansion less than the first coefficient of thermal expansion to limit the expansion of the opening to the second coefficient of thermal expansion.

Description

INITIATIONThe present invention relates to a bearing interface assembly configured to balance different thermal expansion rates of a bearing and a housing of an installation site.Bearings are installed on a rotating shaft to support the shaft and reduce friction between the shaft and its housing. The bearing allows the shaft to freely rotate while minimizing friction between the shaft and its housing. This helps reduce wear of the shaft and its housing and may help extend the life of a machine containing the shaft. In some applications, the bearing and the housing have different thermal expansion rates.For further background information, reference is made at this point for further details to the publications DE 10 2015 107 005 A1, DE 696 16 906 T2, DE 10 2021 107 282 A1 and DE 11 2004 002 295 T5.SUMMARYAccording to the invention, a bearing interface arrangement is presented which is distinguished by the features of claim 1.The bearing interface assembly is configured to balance different thermal expansion rates of a bearing and a housing of an installation site. The bearing interface assembly includes: a metal sleeve having an outer surface defining a groove and an inner surface defining an opening configured to cooperate with the bearing, the metal sleeve configured to expand with a first coefficient of thermal expansion; and a filament wound composite wrap seated in the groove of the metal sleeve, the filament wound composite wrap configured to expand with a second coefficient of thermal expansion less than the first coefficient of thermal expansion to limit the expansion of the opening to the second coefficient of thermal expansion.In further features, the first coefficient of thermal expansion is equal to a coefficient of thermal expansion of the housing at the installation location; and the second coefficient of thermal expansion is equal to a coefficient of thermal expansion of the bearing.In further features, the metal sleeve is constrained to the groove such that portions of the metal sleeve on opposite sides of the groove may expand with the first coefficient of thermal expansion.In further features, the groove is defined by a first flange and a second flange, the second flange being longer than the first flange.In further features, the filament wound composite wrap is recessed within the groove below an outermost portion of the outer surface.In further features, the metal sleeve is made of aluminum.In further features, the metal sleeve is made of magnesium.In further features, the filament wound composite wrap comprises at least one of the following materials: a carbon fiber, a glass fiber, a basalt fiber, a natural fiber, a liquid crystal polymer, or an ultra high molecular weight polyethylene fiber.In further features, the filament wound composite wrap comprises at least one of: a thermoset resin or a thermoplastic resin; the thermoset resin comprises at least one of: epoxy resin, phenolic resin or bismaleimide resin; and the thermoplastic resin comprises at least one of: polypropylene, nylon, polycarbonate, polyethylene, polyethylene ether ketone or polyether ketone.In further features, the metal sleeve includes a slot configured to cooperate with a tab at an installation location to limit rotation of the metal sleeve.In further features, the filament wound composite wrap is wound onto the outer surface at an angle that is not orthogonal to a longitudinal axis of the metal sleeve and with a varying thickness in a direction parallel to the longitudinal axis.In further features, the groove has a varying depth in a direction parallel to the longitudinal axis.In further features, the filament wound composite wrap is secured to the exterior surface by at least one of dry fiber wrap, wet fiber wrap, thermoplastic fiber wrap, fiber strand wrap, thermoset prepreg wrap, or thermoplastic prepreg wrap.The present invention further comprises, in various features, a bearing interface assembly configured to balance different thermal expansion rates of a bearing and a housing of an installation site. The bearing interface assembly comprises: a metal sleeve having a first flange and a second flange defining a groove therebetween on an outer surface of the metal sleeve, the metal sleeve further comprising an inner surface defining an opening configured to cooperate with the bearing, the metal sleeve and the housing configured to expand with a first coefficient of thermal expansion; and a filament wound composite wrap seated in the groove of the metal sleeve, the filament wound composite wrap and the bearing configured to expand with a second coefficient of thermal expansion less than the first coefficient of thermal expansion to limit the expansion of the opening to the second coefficient of thermal expansion without limiting the expansion of the first flange and the second flange to the first coefficient of thermal expansion.In further features, the groove defines a dovetail shape in cross section.In further features, the metal sleeve consists of at least one of the materials aluminum or magnesium.In further features, the filament wound composite wrap comprises at least one of the following materials: a carbon fiber, a glass fiber, a basalt fiber, a natural fiber, a liquid crystal polymer, or an ultra high molecular weight polyethylene fiber.In further features, the filament wound composite wrap comprises at least one of: a thermoset resin or a thermoplastic resin; the thermoset resin comprises at least one of: epoxy resin, phenolic resin or bismaleimide resin; and the thermoplastic resin comprises at least one of: polypropylene, nylon, polycarbonate, polyethylene, polyethylene ether ketone or polyether ketone.The present invention further comprises, in various features, a bearing interface assembly configured to balance different thermal expansion rates of a bearing and a housing of an installation site. The bearing interface assembly comprises: a metal sleeve having a first flange and a second flange defining a groove therebetween on an outer surface of the metal sleeve, the metal sleeve further comprising an inner surface defining an opening configured to cooperate with the bearing, the metal sleeve and the housing configured to expand with a first coefficient of thermal expansion; and a filament wound composite wrap seated in the groove of the metal sleeve, the filament wound composite wrap and the bearing configured to expand with a second coefficient of thermal expansion less than the first coefficient of thermal expansion to limit the expansion of the opening to the second coefficient of thermal expansion without limiting the expansion of the first flange and the second flange to the first coefficient of thermal expansion. The metal sleeve consists of at least one of the materials aluminum or magnesium. The filament wound composite wrap comprises at least one of the following materials: a carbon fiber, a glass fiber, a basalt fiber, a natural fiber, a liquid crystal polymer, or an ultra high molecular weight polyethylene fiber. The filament wound composite wrap is secured to the outer surface by at least one of the following methods: dry fiber wrap, wet fiber wrap, thermoplastic fiber wrap, fiber strand wrap, thermoset prepreg wrap, or thermoplastic prepreg wrap.In further features, the filament wound composite wrap comprises at least one of: a thermoset resin or a thermoplastic resin; the thermoset resin comprises at least one of: epoxy resin, phenolic resin or bismaleimide resin; and the thermoplastic resin comprises at least one of: polypropylene, nylon, polycarbonate, polyethylene, polyethylene ether ketone or polyether ketone.Further areas of applicability of the present invention will become apparent from the detailed description, claims and drawings. The detailed description and specific examples are provided for illustrative purposes only.BRIEF DESCRIPTION OF THE DRAWINGSThe present invention will be more fully understood from the detailed description and the accompanying drawings, in which: FIG. 1 is a cross-sectional view of an axle housing having two bearing interface assemblies in accordance with the present invention; FIG. 2 is an exploded view of one of the bearing interface assemblies of the present invention; FIG. 3 is a cross-sectional view of the bearing interface assembly of FIG. 2 ; FIG. 4 is a cross-sectional view of a dovetail groove of one of the bearing interface assemblies of the present invention; FIG. 5 is a cross-sectional view of another bearing interface assembly according to the present invention; FIG. 6 is a cross-sectional view of a bearing interface assembly of the present invention defining a slot configured to cooperate with a tab at an installation location to limit rotation of the bearing interface assembly; FIG. 7 is a cross-sectional view of an additional bearing interface assembly of the present invention defining another slot configured to cooperate with a tab to limit rotation of the bearing assembly; and FIG. 8 is a cross-sectional view of an engine including bearing interface assemblies according to the present invention.In the drawings, reference numerals may be used multiple times to identify similar and / or similar elements.DETAILED DESCRIPTIONThe present invention provides a bearing interface assembly configured to balance different thermal expansion rates of a bearing and a housing of an installation site. The assembly includes a metal sleeve defining an opening for the bearing. The metal shell is configured with a first thermal expansion coefficient corresponding to a thermal expansion coefficient of the housing. A filament wound composite wrap is wrapped around the sleeve. The wrap is configured with a second coefficient of thermal expansion that is less than the first coefficient of thermal expansion and equal to a coefficient of thermal expansion of the bearing. The wrap extends around the opening of the metal sleeve to limit the thermal expansion of the opening to the second coefficient of thermal expansion corresponding to that of the bearing, while portions of the metal sleeve without the wrap expand at the first coefficient of thermal expansion to maintain the cooperation with the housing.FIG. 1 illustrates two bearing interface assemblies 10A, 10B according to the present invention. The bearing interface assemblies 10A, 10B are installed in an example housing 510, which in the example of FIG. 1 is a housing for a shaft 550 such as an axle shaft. The housing 510 defines a bore 512 through which the shaft 550 extends. Along the axial center of shaft 550 and bore 512 is a longitudinal axis A. Housing 510 may be made of any suitable material such as aluminum or magnesium. The housing 510 expands at a first coefficient of thermal expansion, the exact rate of which varies depending on the material used for the housing 510.The shaft 550 may be any rotating shaft of a terrestrial vehicle such as an axle shaft, an output shaft, an input shaft, etc. The present invention is also applicable to off-vehicle applications. Thus, shaft 550 may be a rotating shaft of any other suitable machine. The shaft 550 may be, for example, a rotating shaft of a watercraft, aircraft or power plant, such as a wind turbine shaft, a hydro turbine shaft, etc.The bearing interface assembly 10A provides an interface between a bearing assembly 610A on the shaft 550 and an installation location 520A of the housing 510. Bearing assembly 610A includes an outer race 612 in cooperation with bearing interface assembly 10A, an inner race 614 in contact with shaft 550, and a plurality of ball bearings 620 between outer race 612 and inner race 614. The bearing assembly 610A may therefore be a ball bearing assembly or other suitable type of bearing. The bearing interface assembly 10B provides an interface between a bearing assembly 610B and the housing 510 at a second installation location 520B of the housing 510. Bearing assembly 610B is similar to bearing assembly 610A. In the example of FIG. 1, bearing assembly 610A is a head bearing and, therefore, bearing interface assembly 10A is configured as a head bearing interface. The bearing assembly 610B is configured as a rear bearing and therefore the bearing interface assembly 10B is configured as a rear bearing interface.The first installation location 520A is milled into the housing 510 to enclose a conical surface 522. The bearing interface assembly 10A is press fit into a circular bore at the bottom (i.e., an innermost portion) of the conical surface 522 that is joined to the flange 32 to secure the bearing interface assembly 10A to the first installation location 520A. Flange 34 may be higher than flange 32 to facilitate attachment of assembly 10A to first installation location 520A and to allow flange 34 to expand in cooperation with housing 510. Likewise, the bearing interface assembly 10B may be press fit into the second installation location 520B or may otherwise be secured to the second installation location 520B in any suitable manner with any suitable mechanical lock.With additional reference to FIGS. 2 and 3, the bearing interface assembly 10A will now be described in more detail. The bearing interface assembly 10A includes a metal sleeve 20 defining an opening 40. When installed at the first installation location 520A, the shaft 550 passes through the opening 40.The metal sleeve 20 includes an outer surface 22 and an inner surface 24 opposite the outer surface 22. The outer surface 22 of the metal sleeve 20 defines a groove 30 thereon, the groove 30 being located between a first flange 32 and a second flange 34 of the metal sleeve 20, the outer surface 22 of the metal sleeve including outer surfaces of the first flange 32 and the second flange 34. the inner surface 24 is in contact with the outer race 612 of the first bearing assembly 610A. Adjacent the inner surface 24 is a side wall 26 of the metal sleeve 20 against which the outer race 612 abuts.The metal sleeve 20 may be made of any suitable metallic material such as aluminum or magnesium. The metal shell 20 is usually made of the same material as the housing 510 to impart a first coefficient of thermal expansion to the metal shell that is the same or similar to the coefficient of thermal expansion of the housing 510.The bearing interface assembly 10A further includes a filament wound composite wrap 110. The filament wound composite wrap 110 extends around the metal sleeve 20 on the outer surface within the groove 30, the wrap 110 having a maximum thickness T 1 that is less than or equal to the depth of the groove 30, such that the wrap 110 does not protrude beyond the first flange 32 and the second flange 34. When installed at the first installation location 520A, the first flange 32 and the second flange 34 are in contact with the housing 510.In the example of FIG. 3, the groove 30 does not have a uniform depth, and the wrap 110 is wrapped around the metal shell 20 into the groove 30 at an angle θ 1 that is not orthogonal to the longitudinal axis A and the central axis of the opening 40. The wrap 110 has an uneven thickness that generally reflects an uneven thickness of the outer race 612. Thus, a maximum thickness portion of the wrap 110 faces a maximum thickness portion of the outer race 612, and a thinnest portion of the wrap 110 faces a thinnest portion of the outer race 612. In other applications, as shown in FIG. 1, the groove 30 may have a uniform depth and therefore the wrap 110 may have a uniform thickness. Referring to FIG. 4, the groove 30 may have beveled side walls to provide the groove with a dovetail shape in cross section. The dovetail shaped sidewalls are configured to additionally secure the wrap 110 within the groove 30.The filament wound composite wrap 110 is configured with a second coefficient of thermal expansion that is less than the first coefficient of thermal expansion of the metal sleeve 20. The second coefficient of thermal expansion is equal to or about equal to a coefficient of thermal expansion of the first bearing assembly 610A (similarly, the wrap 110 is configured with a second coefficient of thermal expansion equal to or about equal to a coefficient of thermal expansion of the second bearing assembly 610B). The wrap 110 limits thermal expansion of portions of the metal sleeve 20 enclosed by the wrap 110 that includes the opening 40. Thus, the opening 40 extends at the same speed as the first bearing assembly 610A. The wrap 110 does not restrict thermal expansion of the first and second flanges 32, 34 so that the first and second flanges 32, 34 can expand with the first coefficient of thermal expansion.The filament wound composite wrap 110 comprises one or more of the following materials: carbon fibers; glass fibers; basalt fibers; natural fibers; a liquid crystal polymer; or an ultra high molecular weight polyethylene fiber. The wrap 110 further comprises a thermally cured material or a thermoplastic material. Examples of thermally cured materials include, but are not limited to, an epoxy resin, a phenolic resin, and a bismaleimide resin. Examples of thermoplastic materials include, but are not limited to, polypropylene, nylon, polycarbonate, polyethylene, polyethylene ether ketone (PEEK), and polyether ketone (PEK). The wrap 110 is wrapped around the metal sleeve 20 within the groove and is secured to the outer surface 22 in any suitable manner, such as by dry or wet fiber winding, thermoplastic fiber winding, or fiber strand winding. The wrap 110 may be cured on the outer surface 22, thereby leaving the fibers of the wrap 110 under tension after completion of the curing process.When the metal shell 20 is exposed to heat sufficient to cause the housing 510 and the first bearing assembly 610 to expand, the metal shell 20 expands with the first coefficient of thermal expansion to maintain contact with the housing 510. Therefore, the first flange 32 and the second flange 34 expand outward at the same rate as the housing 510. However, portions of the metal sleeve 20 wrapped with the filament wound composite wrap 110 are constrained by the wrap 110 to expand at the first coefficient of thermal expansion and instead expand at the second coefficient of thermal expansion of the wrap 110. As a result, portions of the metal sleeve 20 surrounded by the wrap 110, such as the aperture 40, expand at the same rate as the first bearing assembly 610A, thereby preventing thermal expansion mismatch between the housing 510 and the first bearing assembly 610A to maintain the relative positioning between the metal sleeve and the first bearing assembly 610A. This configuration improves the efficiency of the bearing assembly 610A and reduces the possibility of noise and vibration issues.FIG. 5 illustrates another bearing interface assembly 10B in accordance with the present invention. The assembly 10B is generally similar to the first bearing interface assembly 10A, and features of the assembly 10B that are identical or similar to the features of the assembly 10A are denoted by the same reference numerals in the figures. The description of the arrangement 10A also applies to the arrangement 10B in terms of the similar features. The metal sleeve 20 of the second bearing interface assembly 10B has a similar shape to the metal sleeve 20 of the assembly 10A, however, the sleeve 20 of the assembly 10B is somewhat elongated to accommodate the shape of the housing 510 at the second installation location 520B. Another difference between the assemblies 10A, 10B is that the groove 30 of the bearing interface assembly 10B is slightly deeper. The outer surface 22 of the groove 30 of the assembly 10B is further inclined by an angle θ 2 that is greater than the angle θ 1 of the assembly 10A. Thus, the wrap 110 of the assembly 10B is wrapped at a steeper angle relative to the longitudinal axis A than the angle at which the wrap 110 is wrapped. The wrap 110 of the assembly 10B is thicker than the wrap 110 of the assembly 10A to receive the thicker outer race 612 of the second bearing assembly 610B.Referring to FIG. 6, the present invention provides an additional bearing interface assembly 10C that is similar to the bearing interface assembly 10A. Unlike the assembly 10A, the assembly 10C defines a slot 50. the slot 50 is configured to cooperate with any suitable tab, knob, etc., of the first installation location 520A to limit rotation of the assembly 10C. Moreover, the groove 30 of the assembly 10C has a uniform depth such that the wrap 110 has a uniform thickness T 3 around the metal shell 20.FIG. 7 illustrates another bearing interface assembly 10D in accordance with the present invention. The assembly 10D is similar to the assembly 10B and, therefore, the same reference numerals are used to designate features that are the same or substantially similar. Unlike the assembly 10B, the assembly 10D defines a slot 50 configured to cooperate with any suitable tab, button, etc., of the second installation location 520B to prevent rotation of the assembly 10D when installed at the second installation location 520B. Moreover, the groove 30 of the assembly 10D has a uniform depth such that the wrap 110 has a uniform thickness T 4 around the metal shell 20. The thickness T 4 of the wrap 110 is greater than the thickness T 3 of FIG. 5.In addition to preventing rotation, slots 50 also facilitate installation of assemblies 10C and 10D. The slots 50 are configured such that the metal of the metal sleeve 20 is easily bent and allows a sliding fit of the bearing assemblies 610A, 610B into the metal sleeves 20 before the wrap 110 is attached. When the bearing assemblies 610A, 610B are inserted into the metal sleeves 20, the flanges of the metal sleeves 20 flex so that the bearing assemblies 610A, 610B can be easily slid into the metal sleeves 20. The metal sleeves 20 are then wrapped with the wraps 110, and the bearing assemblies 610A, 610B are fixed in place by the pressure exerted inward from the composite wrap 110.Figure 8 shows another application for the bearing interface assemblies 10A-10D of the present invention. FIG. 8 shows an example motor 710 having an output shaft 712 and an input shaft 714. The output shaft 712 is connected to the input shaft 714 via a suitable reduction gear 720.The output shaft 712 passes through two of the bearing interface assemblies 10A. The drive shaft 714 passes through three of the bearing interface assemblies 10A. Although FIG. 7 illustrates the motor 710 with the bearing interface assemblies 10A, any other bearing interface assemblies 10B- 10D may be included in place of or in addition to the assemblies 10A.

Claims

A bearing interface assembly (10A-10D) configured to balance different thermal expansion rates of a bearing (610A) and a housing (510) of an installation site, the bearing interface assembly (10A-10D) comprising: a metal sleeve (20) having an outer surface (22) defining a groove (30) and an inner surface (24) defining an opening (40) configured to cooperate with the bearing (610A), the metal sleeve (20) configured to expand with a first thermal expansion coefficient; and a filament wound composite wrap (110) seated in the groove (30) of the metal sleeve (20), the filament wound composite wrap (110) configured to expand at a second coefficient of thermal expansion less than the first coefficient of thermal expansion to limit the expansion of the aperture (40) to the second coefficient of thermal expansion.The bearing interface assembly (10A-10D) of claim 1, wherein: the first coefficient of thermal expansion is equal to a coefficient of thermal expansion of the housing (510) at the installation location; and the second coefficient of thermal expansion is equal to a coefficient of thermal expansion of the bearing (610A).The bearing interface assembly (10A-10D) of claim 1, wherein the metal sleeve (20) is constrained to the groove (30) such that portions of the metal sleeve (20) on opposite sides of the groove (30) can expand with the first coefficient of thermal expansion.The bearing interface assembly (10A-10D) of claim 1, wherein the groove (30) is defined by a first flange (32) and a second flange (34), the second flange (34) being longer than the first flange (32).The bearing interface assembly (10A-10D) of claim 1, wherein the filament wound composite wrap (110) is recessed within the groove (30) below an outermost portion of the outer surface (22).The bearing interface assembly (10A-10D) of claim 1, wherein the metal sleeve (20) is made of aluminum.The bearing interface assembly (10A-10D) of claim 1, wherein the metal sleeve (20) is made of magnesium.The bearing interface assembly (10A-10D) of claim 1, wherein the filament wound composite wrap (110) comprises at least one of the following materials: a carbon fiber, a glass fiber, a basalt fiber, a natural fiber, a liquid crystal polymer, or an ultra high molecular weight polyethylene fiber.The bearing interface assembly (10A-10D) of claim 1, wherein: the filament wound composite wrap (110) comprises at least one of: a thermoset resin or a thermoplastic resin; the thermoset resin comprises at least one of: epoxy resin, phenolic resin, or bismaleimide resin; and the thermoplastic resin comprises at least one of: polypropylene, nylon, polycarbonate, polyethylene, polyethylene ether ketone, or polyether ketone.The bearing interface assembly (10C, 10D) of claim 1, wherein the metal sleeve (20) includes a slot (50) configured to cooperate with a tab at an installation location to restrict rotation of the metal sleeve (20).

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