CA2363866A1 - Compliant braided metal bearing for use in bushing application - Google Patents
Compliant braided metal bearing for use in bushing application Download PDFInfo
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- CA2363866A1 CA2363866A1 CA 2363866 CA2363866A CA2363866A1 CA 2363866 A1 CA2363866 A1 CA 2363866A1 CA 2363866 CA2363866 CA 2363866 CA 2363866 A CA2363866 A CA 2363866A CA 2363866 A1 CA2363866 A1 CA 2363866A1
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- socket joint
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Abstract
A compliant metal bearing for use in movable sockets is formed from a braided or knitted metal wire mesh preform which is compressed in a die to achieve the desired shape. The surfaces of the compressed braided metal bearing are hardened, and may have a thermally stable lubricant embedded within the mesh. By selecting the metallic properties of the wire, the knit pattern, the compressed wire density, and the addition of other materials such as sheet metal to the preform, the radial and axial compliance properties of the braided or knitted metal wire bearings of the present invention may be selected and controlled for specific applications within a ball and socket joint, allowing ball and socket joints to be designed with reduced size and increased heat resistant properties.
Description
FOR USE IN
BUSHING APPLICATION
BACKGROUND OF THE INVENTION
The present invention is directed towards an apparatus and method for providing a socket or ball joint bearing having elastomeric properties while maintaining energy storage, wear, and temperature resistance characteristics of high strength steel, and more particularly to a compliance bearing composed of a compressed braided or knitted metal wire mesh. While the invention is described in detail with respect to automotive applications, those skilled in the art will recognized the broader applicability of the invention.
Conventional ball joints, and other movable sockets, such as are shown in U.S.
patent No. 4,875,794 to Kern, Jr. are used, for example, in automotive steering and suspension applications. The sockets typically comprise a housing having a circular cylindrical internal surface, a ball stud with a ball head contained in the housing, and one or more conventional synthetic resin or a solid Sintered alloy bearing member supporting the ball head within the housing. These components are installed into the housing through a posterior opening, with the ball stud extending outward through an axially disposed anterior opening of a smaller diameter than the ball head. Traditionally, the posterior opening is closed by means of a cover-plate, spun, swaged, or welded in place. Once secured in place, the cover-plate presses on the conventional . - ~ 2 bearing member either directly or indirectly through a resilient rubber intermediate component and a pressure plate.
Conventional bearing components within the housing, against which the ball head or moveable component is articulated, perform best when the sliding surfaces are fully hardened, as it is better able to withstand the stresses and frictional wear associated with movement of the conventional bearing components. Bearing components in a movable socket are subjected to rotational, axial, and radial loads. Accordingly, the use of hardened materials greatly extends the useful life of the bearing components and the housing. Currently, the minimum size for conventional bearing components is limited by the level of surface area for load distribution. As the size of conventional bearings is reduced, the pressure on the surface of the bearings correspondingly increase, leading to premature breakdown of conventional bearing materials such as synthetic polymers.
Once assembled, movable sockets may be utilized as load carrying members in numerous mechanical systems, including automotive vehicle suspension and steering systems. Movable sockets or ball joints employed in these applications are subjected to various operating conditions, and may be required to carry substantial loads. When wear develops, the performance of the movable socket or ball joint degrades and, in the' case of automotive applications, may result in erratic steering or excessive looseness and play in the vehicle suspension system.
Degradation in the performance of conventional bearing components further limits their use in high-temperature applications such as in locations adjacent to radiant heat sources, i.e. vehicle brake discs or brake drums. Additionally, in order to obtain the required elastomeric properties, conventional bearing components must be manufactured of a sufficiently large size, limiting efforts to minimize overall size for the movable socket.
Accordingly, it is desirable to develop a movable socket bearing which is of a small size, high strength, retains the elastomeric properties of a conventional bearing, including the ability to comply or flex to a limited extend under application of axial and radial toads, and which is heat resistant in high-temperature applications.
It has been known in the industry, as taught by U.S. Patent No. 6,025,018 to Goldman et al., herein incorporated by reference, that metal wire may be knitted or braided into a wire mesh for formation into discrete preforms for articles of manufacture such as gaskets and seals by conventional die compression. United States Patent Nos. 4,607,81; 4,601,476;
4,516,782 and 4,417,733 each to Usher, and each herein incorporated by reference, describe such high temperature gaskets which are particularly suited for use in vehicle engine exhaust systems wherein they experience rotational loads while maintaining a gas-tight seal.
These gaskets are formed by placing a tubular preform of wire mesh into a die cavity, along with other desired materials such as refractory metals or thermally stable lubricants, and pressing the wire mesh and materials into a final size and shape of the gasket for curing at a high temperature. The resulting gaskets are then utilized as rotational fittings between exhaust pipes, to permit relative rotation of the pipes without impairment of the effectiveness of the seal, thereby preventing leakage of the high temperature exhaust gasses passing through the pipes. In such applications, axial and radial loads experienced by the gasket are minimized by the other structural elements of the exhaust pipe fittings, and accordingly, the wire mesh gaskets are not configured substantially td resist such loading forces and the associated wear.
Accordingly, it would by highly desirous to develop a bearing for a movable socket which is capable of supporting the stud against the rotational, axial, and radial loads found in a movable socket in much the same way as a conventional polymer bearing, but which additionally incorporates the resistance to the high temperatures, and the wear characteristics found in the wire mesh gaskets utilized in vehicle exhaust systems.
BRIEF SUMMARY OF THE INVENTION
Among the several objects and advantages of the present invention are:
The provision of a new and improved compliance bearing for use in movable sockets;
The provision of the aforementioned compliance bearing wherein the bearing permits a reduction in the number of components utilized in the movable socket;
The provision of the aforementioned compliance bearing wherein the bearing permits a reduction in the size of components utilized in the movable socket;
The provision of the aforementioned compliance bearing wherein the bearing has the wear characteristics of a high hardness steel;
The provision of the aforementioned compliance bearing wherein the bearing has improved axial and radial vibration dampening characteristics;
The provision of the aforementioned compliance bearing wherein the bearing has elastomeric characteristics;
The provision of the aforementioned compliance bearing wherein the bearing is sufficiently porous to permit a flow of lubrication to the bearing surfaces;
The provision of the aforementioned compliance bearing wherein the bearing may be specifically constructed to provide for desired axial and radial compliance requirements;
The provision of the aforementioned compliance bearing wherein the bearing is suitable for use in high temperature applications;
The provision of the aforementioned compliance bearing wherein the bearing conforms to adjacent surfaces to reduce localized contact pressure points; and The provision of the aforementioned compliance bearing wherein the bearing is composed of a compacted braided or knitted wire mesh.
Briefly stated, the compliant metal bearing of the present invention for use in movable sockets is formed from a braided or knitted metal wire mesh preform which is compressed in a die to achieve the desired shape. The compressed braided metal bearing is optionally hardened, and may have a thermally stable lubricant embedded within the mesh. By selecting the metallic properties of the wire, the knit pattern, the die shape, and the bearing compaction density, the radial and axial compliance properties of the braided or knitted metal wire compliance bearings of the present invention may be selected and controlled for specific applications within a ball and socketjoint.
The foregoing and other objects, features, and advantages of the invention as well as presently preferred embodiments thereof will become more apparent from the reading of the following description in connection with the accompanying drawings.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS
In the accompanying drawings which form part of the specification:
Figure 1 is a perspective view of a an embodiment of a compliant metal bearing of the present invention;
Figure 2 is an exploded view of a conventional movable socket in which a braided metal compliance bearing of the present invention may be utilized;
Figure 3 is a sectional view of the assembled conventional movable socket shown in Fig.
BUSHING APPLICATION
BACKGROUND OF THE INVENTION
The present invention is directed towards an apparatus and method for providing a socket or ball joint bearing having elastomeric properties while maintaining energy storage, wear, and temperature resistance characteristics of high strength steel, and more particularly to a compliance bearing composed of a compressed braided or knitted metal wire mesh. While the invention is described in detail with respect to automotive applications, those skilled in the art will recognized the broader applicability of the invention.
Conventional ball joints, and other movable sockets, such as are shown in U.S.
patent No. 4,875,794 to Kern, Jr. are used, for example, in automotive steering and suspension applications. The sockets typically comprise a housing having a circular cylindrical internal surface, a ball stud with a ball head contained in the housing, and one or more conventional synthetic resin or a solid Sintered alloy bearing member supporting the ball head within the housing. These components are installed into the housing through a posterior opening, with the ball stud extending outward through an axially disposed anterior opening of a smaller diameter than the ball head. Traditionally, the posterior opening is closed by means of a cover-plate, spun, swaged, or welded in place. Once secured in place, the cover-plate presses on the conventional . - ~ 2 bearing member either directly or indirectly through a resilient rubber intermediate component and a pressure plate.
Conventional bearing components within the housing, against which the ball head or moveable component is articulated, perform best when the sliding surfaces are fully hardened, as it is better able to withstand the stresses and frictional wear associated with movement of the conventional bearing components. Bearing components in a movable socket are subjected to rotational, axial, and radial loads. Accordingly, the use of hardened materials greatly extends the useful life of the bearing components and the housing. Currently, the minimum size for conventional bearing components is limited by the level of surface area for load distribution. As the size of conventional bearings is reduced, the pressure on the surface of the bearings correspondingly increase, leading to premature breakdown of conventional bearing materials such as synthetic polymers.
Once assembled, movable sockets may be utilized as load carrying members in numerous mechanical systems, including automotive vehicle suspension and steering systems. Movable sockets or ball joints employed in these applications are subjected to various operating conditions, and may be required to carry substantial loads. When wear develops, the performance of the movable socket or ball joint degrades and, in the' case of automotive applications, may result in erratic steering or excessive looseness and play in the vehicle suspension system.
Degradation in the performance of conventional bearing components further limits their use in high-temperature applications such as in locations adjacent to radiant heat sources, i.e. vehicle brake discs or brake drums. Additionally, in order to obtain the required elastomeric properties, conventional bearing components must be manufactured of a sufficiently large size, limiting efforts to minimize overall size for the movable socket.
Accordingly, it is desirable to develop a movable socket bearing which is of a small size, high strength, retains the elastomeric properties of a conventional bearing, including the ability to comply or flex to a limited extend under application of axial and radial toads, and which is heat resistant in high-temperature applications.
It has been known in the industry, as taught by U.S. Patent No. 6,025,018 to Goldman et al., herein incorporated by reference, that metal wire may be knitted or braided into a wire mesh for formation into discrete preforms for articles of manufacture such as gaskets and seals by conventional die compression. United States Patent Nos. 4,607,81; 4,601,476;
4,516,782 and 4,417,733 each to Usher, and each herein incorporated by reference, describe such high temperature gaskets which are particularly suited for use in vehicle engine exhaust systems wherein they experience rotational loads while maintaining a gas-tight seal.
These gaskets are formed by placing a tubular preform of wire mesh into a die cavity, along with other desired materials such as refractory metals or thermally stable lubricants, and pressing the wire mesh and materials into a final size and shape of the gasket for curing at a high temperature. The resulting gaskets are then utilized as rotational fittings between exhaust pipes, to permit relative rotation of the pipes without impairment of the effectiveness of the seal, thereby preventing leakage of the high temperature exhaust gasses passing through the pipes. In such applications, axial and radial loads experienced by the gasket are minimized by the other structural elements of the exhaust pipe fittings, and accordingly, the wire mesh gaskets are not configured substantially td resist such loading forces and the associated wear.
Accordingly, it would by highly desirous to develop a bearing for a movable socket which is capable of supporting the stud against the rotational, axial, and radial loads found in a movable socket in much the same way as a conventional polymer bearing, but which additionally incorporates the resistance to the high temperatures, and the wear characteristics found in the wire mesh gaskets utilized in vehicle exhaust systems.
BRIEF SUMMARY OF THE INVENTION
Among the several objects and advantages of the present invention are:
The provision of a new and improved compliance bearing for use in movable sockets;
The provision of the aforementioned compliance bearing wherein the bearing permits a reduction in the number of components utilized in the movable socket;
The provision of the aforementioned compliance bearing wherein the bearing permits a reduction in the size of components utilized in the movable socket;
The provision of the aforementioned compliance bearing wherein the bearing has the wear characteristics of a high hardness steel;
The provision of the aforementioned compliance bearing wherein the bearing has improved axial and radial vibration dampening characteristics;
The provision of the aforementioned compliance bearing wherein the bearing has elastomeric characteristics;
The provision of the aforementioned compliance bearing wherein the bearing is sufficiently porous to permit a flow of lubrication to the bearing surfaces;
The provision of the aforementioned compliance bearing wherein the bearing may be specifically constructed to provide for desired axial and radial compliance requirements;
The provision of the aforementioned compliance bearing wherein the bearing is suitable for use in high temperature applications;
The provision of the aforementioned compliance bearing wherein the bearing conforms to adjacent surfaces to reduce localized contact pressure points; and The provision of the aforementioned compliance bearing wherein the bearing is composed of a compacted braided or knitted wire mesh.
Briefly stated, the compliant metal bearing of the present invention for use in movable sockets is formed from a braided or knitted metal wire mesh preform which is compressed in a die to achieve the desired shape. The compressed braided metal bearing is optionally hardened, and may have a thermally stable lubricant embedded within the mesh. By selecting the metallic properties of the wire, the knit pattern, the die shape, and the bearing compaction density, the radial and axial compliance properties of the braided or knitted metal wire compliance bearings of the present invention may be selected and controlled for specific applications within a ball and socketjoint.
The foregoing and other objects, features, and advantages of the invention as well as presently preferred embodiments thereof will become more apparent from the reading of the following description in connection with the accompanying drawings.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS
In the accompanying drawings which form part of the specification:
Figure 1 is a perspective view of a an embodiment of a compliant metal bearing of the present invention;
Figure 2 is an exploded view of a conventional movable socket in which a braided metal compliance bearing of the present invention may be utilized;
Figure 3 is a sectional view of the assembled conventional movable socket shown in Fig.
2;
Figure 4 is a sectional view of an alternate design of a conventional movable socket in which a pair of braided metal compliance bearings are utilizes with a spherical stud;
Figure ~ is a sectional view similar to Figure 4 illustrating an alternate housing;
Figure 6 is a sectional view similar to Figure 4, with the socket in a inverted position, illustrating the use of a washer-configuration braided metal compliance bearing of the present invention;
Figure 7 is a sectional view similar to Figure 4, illustrating an elongated stud and a cylindrical configuration braided metal compliance bearing of the present invention;
Figure 8 is a sectional view similar to Figure 4, with the socket in an inverted position, illustrating an alternate stud head and braided metal compliance bearing configuration; and Figure 9 is a sectional view similar to Figure 5, with the socket in an inverted position, illustrating an alternate housing, stud, and braided metal compliance bearing configuration.
Corresponding reference numerals indicate corresponding parts throughout the several figures of the drawings.
DESCRIPTION OF THE PREFERRED EMBODIMENT
The following detailed description illustrates the invention by way of example and not by way of limitation. The description clearly enables one skilled in the art to make and use the invention, describes several embodiments, adaptations, variations, alternatives, and uses of the invention, including what is presently believed to be the best mode of carrying out the invention.
Refernng generally to Figure 1, a compliant metal bearing of the present invention is shown generally at 10. The bearing 10 is preferably in an endless ring form as shown, and has an inner radial surface 12 and an outer radial surface I4. The surfaces 12 and 14 are formed to seat against a stud ball component and against the inner surface of a socket housing, an example of such ball and socket joint being shown and described later with regards to Figure 2. The present compliant metal bearing 10 is formed of a knitted or braided wire mesh 16. The wire mesh 16 is preferably made of steel, but other materials having comparable strength and resiliency could be used as well, or in conjunction therewith. For example, a non-ferrous metal or a low-carbon wire may be utilized, depending upon the desired application for the compliant metal bearing 10, and sheets of flexible material such as lubricating graphite may be incorporated therein.
Conventional techniques for the manufacture of seals from braided or knitted wire mesh, such as are disclosed in U.S. Patent No. 5,499,825 to Maeda et al., and herein incorporated by reference, may be utilized to form the compliant metal bearing 10. The knitted or braided wire mesh 16, and any additional material, is preferably formed into a tubular or cylindrical shape, and loaded into a conventional compression die (not' shown) which has a cavity shaped substantially the same size as that of the finished compliant metal bearing 10. The die is designed in such a manner that compression force is applied axially to the loaded knitted or braided wire mesh 16 to cause the knitted or braided wire mesh 16, and any additional material, to collapse to the size and shape of the finished compliant metal bearing 10, and having a desired degree of compaction density to provide the desired axial and radial stiffness.
8, In an alternate embodiment, the knitted or braided wire mesh 16 may be formed from a high-strength carbon or stainless steel, and the compression operation accompanied by a heating process, thereby causing the knitted or braided wire mesh 16 to relay or creep as it is compressed, resulting in a hardened and densely packed finished compliant metal bearing 10 after removal of the compression force and cooling to ambient temperatures.
In a second alternative embodiment, the knitted or braided wire mesh 16 may be formed from a low-carbon wire, which is compressed into the desired bearing shape as described above.
Once removed from the die, the compliant metal bearing 10 formed from the low carbon wire is then gas carburized, quenched and drawn to infuse carbon into the metal, thereby strengthening it to improve the elastic properties and bearing surface wear characteristics.
In a third alternative embodiment, the die into which the knitted wire mesh 16 is compressed is configured such that the resulting bearing is in the shape of a porous, elastic washer 11 suitable for conforming between adjacent surfaces within a ball and socket joint, processed as described in the methods noted above, and used as will be described below.
With any of the above embodiments, it will be readily appreciated by one of ordinary skill in the art that the resulting compliant metal bearing 10 will be porous, having numerous air pockets contained within the compressed knitted wire mesh 16. For some low friction applications, a lubricating material, such as graphite, TeflonTM based materials, or greases may be infused into air pockets of the compliant metal bearing 10, such that a lubricant supply to the surface of the compliant metal bearing I 0 may be maintained during use.
Referring generally to Figures 2 and 3, the compliant metal bearing 10 of the present invention may be used with any conventional movable socket, such as the ball joint shown at 100, within a housing 112. Those skilled in the art will readily recognize the applicability of the compliant metal bearing of the present invention in a variety of different movable sockets including those having only one housing opening; to facilitate the description of the claimed apparatus, the preferred embodiment of present invention is described in reference to the exemplary ball joint 110, but is not limited to use therewith. Similar concepts could be employed for use as compliant bushings which could replace, for instance, automotive control arm bushings.
Housing 112, within which the various internal components of the ball joint are enclosed, is generally cylindrical, with a central bore 114 of non-uniform radius having a posterior opening 116 and an anterior opening 118. The radius R of central bore 114 decreases to define a curved surface 120 at the base of the housing, adjacent anterior opening 118. A
counterbore 122 having a circumferential groove 124 is formed in bore 114, adjacent the posterior opening 116. The exterior surface 126 of housing 112 may follow the general contour of the central bore 114. In the embodiment illustrated, the surface 126 has an expanded ridge 128 formed in it. The ridge 128 is used for attachment of ball joint 100 to other components (not shown).
As may be appreciated, the ridge 128 also may be adapted for other specific kinds of installations employing threads or other connectors (not shown).
To assemble ball joint 100, a lower compliant metal bearing 130 of the present invention, sized to fit within central bore 114 is seated within housing 112.
The lower compliant metal bearing 130 includes a central bore 132 axially aligned with a vertical axis VA of the housing, and a curved outer surface 134 of lower compliant metal bearing 130 is designed to correspond to the curvature of surface 120 in housing 112. Next, a stud 136 having a generally cylindrical body 138 and an enlarged head portion 140 with a circumferential flange I42 is passed through central bores 132 and 114, such that the underside 144 of flange I42 rests on an upper surface 146 of the lower compliant metal bearing 130 seated within the housing. The body 138 includes a uniform diameter upper portion 150 adjacent flange 142, a tapered central portion 1~2, and a lower portion 154 of a narrow uniform diameter. The upper portion 150 is sized to fit within the central bore 132 of lower compliant metal bearing 130, with the central portion 152 and lower portion 1 ~4 extending through the anterior opening 118, externally of housing 112.
The head portion 140 includes a hemispherical surface I~6 with a radius RH
greater than that of upper portion 1 ~0, but less than radius R of the housing I I2. When assembled, the hemispherical surface 156 and the curved outer surface 134 define a generally spherical unit within housing 112, allowing for conical movement of stud 136. Those skilled in the art will readily recognize that numerous shapes and configurations for stud 136 and lower compliant metal bearing I30 are possible. For example, the stud 136 may include a generally spherical head, altering the configuration of the lower compliant metal bearing 130 as seen in Figures 4-6, an elongated head as seen in Figure 7, or a symmetrical head as seen in Figures 8 and 9, or the cylindrical body may include threads (not shown), bores as at 158, or grooves as at 160; for attachment of external components (not shown).
Once stud 136 and the lower compliant metal bearing 130 are seated within the housing, a pressure plate 162 and rubber cushion 164 are placed within central bore 114, above ~ hemispherical surface I56, and secured therein by an expanding cover-plate 166. The pressure plate 162 sits on top of stud 136, and includes a curved indentation 168 having a radius of curvature corresponding to RH. Rubber cushion 164 sits, in turn, on an upper surface 172 of pressure plate 162, and serves to hold the pressure plate 162 in place against the stud 136 while simultaneously permitting small movements in response to the conical movement of the stud.
The rubber cushion includes an circumferential tones 174, having an axial hole 176 formed in it through which a lubrication port 170 extends. Finally, cover-plate 166, shown in an un-expanded conical configuration in Fig. 2, is placed above the rubber cushion 164 along counter-bore 122, for vertical compression and lateral expansion, to seat within circumferential groove 124 and enclose the various components within housing 112. To facilitate the insertion of the cover-plate 166 within the posterior opening of housing 112, the cover-plate 166 includes a circumferential rim 178 having and outer diameter OD sized to fit within counter-bore 122.
As indicated above, those skilled in the art will recognize that the various internal components of the moveable socket secured within the housing 112 by the cover plate 166 may be altered depending upon the particular application for which the movable socket is designed, and accordingly, the above described ball joint 110 is merely exemplary of one embodiment. For example as seen in Figures 4-8, an upper compliant metal bearing 200, formed as taught by the present invention, may be interposed between the pressure plate 162 and the top of the stud 136, or may, replace the pressure plate 162 completely, as seen in Figure 9.
Alternatively, as seen in Figure 6, the ball joint 11'0 may be provided with one or more of the compliant braided or knitted metal bearings 10 of the present invention having an alternate washer embodiment 1 l, as described above. Each washer embodiment 11 is positioned adjacent either an upper or lower surface of the ball, and conforms to the surface of the ball by flexing or deforming. Spacer elements 210 may be placed between the exterior surface of the washer compliant metal bearings 11 and the inner surface of the housing 112.
Utilizing the compliant metal bearings 10 of the present invention in place of traditional elastomer bearings in conventional ball and socket joints offers several advantages. First, it is possible, by having an upper compliant metal bearing 200 replace and assume the function of the pressure plate 162 and rubber cushion preload device, to reduce the number of components necessary to assemble the ball and socket joint 100, thereby reducing manufacture cost and time.
Second, the compliant nature of the metal bearings 10 of the present invention results in a reduction of localized contact pressure, and a more uniform contact surface between the bearing and the adjacent components, thereby reducing excessive frictional wear and premature socket failure. Excessive friction may be further reduced by the addition of a lubricant to the ball and 10 socket joint, with the porous nature of the compressed wire mesh 16 permitting a flow of lubricant to the contact surfaces of the compliant metal bearing 10. Third, a compliant metal bearing 10 having the same axial and radial elastomeric properties as a conventional elastomer or polymer bearing will be of reduced size, permitting a smaller ball and socket component.
Furthermore; by replacing all elastomer or polymer bearings in a ball and socket application with compliant metal bearings 10 of the present invention, the ability of the socket to withstand high temperature applications is greatly increased. The combination of smaller and heat resistant ball and sockets allows for a wider range of ball and socket applications, for example, in an automotive chassis, a smaller ball and socket joint may be placed closer to a radiant heat source, for example, a brake disk or brake drum.
In view of the above, it will be seen that the several objects of the invention are achieved and other advantageous results are obtained. As various changes could be made in the above constructions without departing from the scope of the invention, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.
Figure 4 is a sectional view of an alternate design of a conventional movable socket in which a pair of braided metal compliance bearings are utilizes with a spherical stud;
Figure ~ is a sectional view similar to Figure 4 illustrating an alternate housing;
Figure 6 is a sectional view similar to Figure 4, with the socket in a inverted position, illustrating the use of a washer-configuration braided metal compliance bearing of the present invention;
Figure 7 is a sectional view similar to Figure 4, illustrating an elongated stud and a cylindrical configuration braided metal compliance bearing of the present invention;
Figure 8 is a sectional view similar to Figure 4, with the socket in an inverted position, illustrating an alternate stud head and braided metal compliance bearing configuration; and Figure 9 is a sectional view similar to Figure 5, with the socket in an inverted position, illustrating an alternate housing, stud, and braided metal compliance bearing configuration.
Corresponding reference numerals indicate corresponding parts throughout the several figures of the drawings.
DESCRIPTION OF THE PREFERRED EMBODIMENT
The following detailed description illustrates the invention by way of example and not by way of limitation. The description clearly enables one skilled in the art to make and use the invention, describes several embodiments, adaptations, variations, alternatives, and uses of the invention, including what is presently believed to be the best mode of carrying out the invention.
Refernng generally to Figure 1, a compliant metal bearing of the present invention is shown generally at 10. The bearing 10 is preferably in an endless ring form as shown, and has an inner radial surface 12 and an outer radial surface I4. The surfaces 12 and 14 are formed to seat against a stud ball component and against the inner surface of a socket housing, an example of such ball and socket joint being shown and described later with regards to Figure 2. The present compliant metal bearing 10 is formed of a knitted or braided wire mesh 16. The wire mesh 16 is preferably made of steel, but other materials having comparable strength and resiliency could be used as well, or in conjunction therewith. For example, a non-ferrous metal or a low-carbon wire may be utilized, depending upon the desired application for the compliant metal bearing 10, and sheets of flexible material such as lubricating graphite may be incorporated therein.
Conventional techniques for the manufacture of seals from braided or knitted wire mesh, such as are disclosed in U.S. Patent No. 5,499,825 to Maeda et al., and herein incorporated by reference, may be utilized to form the compliant metal bearing 10. The knitted or braided wire mesh 16, and any additional material, is preferably formed into a tubular or cylindrical shape, and loaded into a conventional compression die (not' shown) which has a cavity shaped substantially the same size as that of the finished compliant metal bearing 10. The die is designed in such a manner that compression force is applied axially to the loaded knitted or braided wire mesh 16 to cause the knitted or braided wire mesh 16, and any additional material, to collapse to the size and shape of the finished compliant metal bearing 10, and having a desired degree of compaction density to provide the desired axial and radial stiffness.
8, In an alternate embodiment, the knitted or braided wire mesh 16 may be formed from a high-strength carbon or stainless steel, and the compression operation accompanied by a heating process, thereby causing the knitted or braided wire mesh 16 to relay or creep as it is compressed, resulting in a hardened and densely packed finished compliant metal bearing 10 after removal of the compression force and cooling to ambient temperatures.
In a second alternative embodiment, the knitted or braided wire mesh 16 may be formed from a low-carbon wire, which is compressed into the desired bearing shape as described above.
Once removed from the die, the compliant metal bearing 10 formed from the low carbon wire is then gas carburized, quenched and drawn to infuse carbon into the metal, thereby strengthening it to improve the elastic properties and bearing surface wear characteristics.
In a third alternative embodiment, the die into which the knitted wire mesh 16 is compressed is configured such that the resulting bearing is in the shape of a porous, elastic washer 11 suitable for conforming between adjacent surfaces within a ball and socket joint, processed as described in the methods noted above, and used as will be described below.
With any of the above embodiments, it will be readily appreciated by one of ordinary skill in the art that the resulting compliant metal bearing 10 will be porous, having numerous air pockets contained within the compressed knitted wire mesh 16. For some low friction applications, a lubricating material, such as graphite, TeflonTM based materials, or greases may be infused into air pockets of the compliant metal bearing 10, such that a lubricant supply to the surface of the compliant metal bearing I 0 may be maintained during use.
Referring generally to Figures 2 and 3, the compliant metal bearing 10 of the present invention may be used with any conventional movable socket, such as the ball joint shown at 100, within a housing 112. Those skilled in the art will readily recognize the applicability of the compliant metal bearing of the present invention in a variety of different movable sockets including those having only one housing opening; to facilitate the description of the claimed apparatus, the preferred embodiment of present invention is described in reference to the exemplary ball joint 110, but is not limited to use therewith. Similar concepts could be employed for use as compliant bushings which could replace, for instance, automotive control arm bushings.
Housing 112, within which the various internal components of the ball joint are enclosed, is generally cylindrical, with a central bore 114 of non-uniform radius having a posterior opening 116 and an anterior opening 118. The radius R of central bore 114 decreases to define a curved surface 120 at the base of the housing, adjacent anterior opening 118. A
counterbore 122 having a circumferential groove 124 is formed in bore 114, adjacent the posterior opening 116. The exterior surface 126 of housing 112 may follow the general contour of the central bore 114. In the embodiment illustrated, the surface 126 has an expanded ridge 128 formed in it. The ridge 128 is used for attachment of ball joint 100 to other components (not shown).
As may be appreciated, the ridge 128 also may be adapted for other specific kinds of installations employing threads or other connectors (not shown).
To assemble ball joint 100, a lower compliant metal bearing 130 of the present invention, sized to fit within central bore 114 is seated within housing 112.
The lower compliant metal bearing 130 includes a central bore 132 axially aligned with a vertical axis VA of the housing, and a curved outer surface 134 of lower compliant metal bearing 130 is designed to correspond to the curvature of surface 120 in housing 112. Next, a stud 136 having a generally cylindrical body 138 and an enlarged head portion 140 with a circumferential flange I42 is passed through central bores 132 and 114, such that the underside 144 of flange I42 rests on an upper surface 146 of the lower compliant metal bearing 130 seated within the housing. The body 138 includes a uniform diameter upper portion 150 adjacent flange 142, a tapered central portion 1~2, and a lower portion 154 of a narrow uniform diameter. The upper portion 150 is sized to fit within the central bore 132 of lower compliant metal bearing 130, with the central portion 152 and lower portion 1 ~4 extending through the anterior opening 118, externally of housing 112.
The head portion 140 includes a hemispherical surface I~6 with a radius RH
greater than that of upper portion 1 ~0, but less than radius R of the housing I I2. When assembled, the hemispherical surface 156 and the curved outer surface 134 define a generally spherical unit within housing 112, allowing for conical movement of stud 136. Those skilled in the art will readily recognize that numerous shapes and configurations for stud 136 and lower compliant metal bearing I30 are possible. For example, the stud 136 may include a generally spherical head, altering the configuration of the lower compliant metal bearing 130 as seen in Figures 4-6, an elongated head as seen in Figure 7, or a symmetrical head as seen in Figures 8 and 9, or the cylindrical body may include threads (not shown), bores as at 158, or grooves as at 160; for attachment of external components (not shown).
Once stud 136 and the lower compliant metal bearing 130 are seated within the housing, a pressure plate 162 and rubber cushion 164 are placed within central bore 114, above ~ hemispherical surface I56, and secured therein by an expanding cover-plate 166. The pressure plate 162 sits on top of stud 136, and includes a curved indentation 168 having a radius of curvature corresponding to RH. Rubber cushion 164 sits, in turn, on an upper surface 172 of pressure plate 162, and serves to hold the pressure plate 162 in place against the stud 136 while simultaneously permitting small movements in response to the conical movement of the stud.
The rubber cushion includes an circumferential tones 174, having an axial hole 176 formed in it through which a lubrication port 170 extends. Finally, cover-plate 166, shown in an un-expanded conical configuration in Fig. 2, is placed above the rubber cushion 164 along counter-bore 122, for vertical compression and lateral expansion, to seat within circumferential groove 124 and enclose the various components within housing 112. To facilitate the insertion of the cover-plate 166 within the posterior opening of housing 112, the cover-plate 166 includes a circumferential rim 178 having and outer diameter OD sized to fit within counter-bore 122.
As indicated above, those skilled in the art will recognize that the various internal components of the moveable socket secured within the housing 112 by the cover plate 166 may be altered depending upon the particular application for which the movable socket is designed, and accordingly, the above described ball joint 110 is merely exemplary of one embodiment. For example as seen in Figures 4-8, an upper compliant metal bearing 200, formed as taught by the present invention, may be interposed between the pressure plate 162 and the top of the stud 136, or may, replace the pressure plate 162 completely, as seen in Figure 9.
Alternatively, as seen in Figure 6, the ball joint 11'0 may be provided with one or more of the compliant braided or knitted metal bearings 10 of the present invention having an alternate washer embodiment 1 l, as described above. Each washer embodiment 11 is positioned adjacent either an upper or lower surface of the ball, and conforms to the surface of the ball by flexing or deforming. Spacer elements 210 may be placed between the exterior surface of the washer compliant metal bearings 11 and the inner surface of the housing 112.
Utilizing the compliant metal bearings 10 of the present invention in place of traditional elastomer bearings in conventional ball and socket joints offers several advantages. First, it is possible, by having an upper compliant metal bearing 200 replace and assume the function of the pressure plate 162 and rubber cushion preload device, to reduce the number of components necessary to assemble the ball and socket joint 100, thereby reducing manufacture cost and time.
Second, the compliant nature of the metal bearings 10 of the present invention results in a reduction of localized contact pressure, and a more uniform contact surface between the bearing and the adjacent components, thereby reducing excessive frictional wear and premature socket failure. Excessive friction may be further reduced by the addition of a lubricant to the ball and 10 socket joint, with the porous nature of the compressed wire mesh 16 permitting a flow of lubricant to the contact surfaces of the compliant metal bearing 10. Third, a compliant metal bearing 10 having the same axial and radial elastomeric properties as a conventional elastomer or polymer bearing will be of reduced size, permitting a smaller ball and socket component.
Furthermore; by replacing all elastomer or polymer bearings in a ball and socket application with compliant metal bearings 10 of the present invention, the ability of the socket to withstand high temperature applications is greatly increased. The combination of smaller and heat resistant ball and sockets allows for a wider range of ball and socket applications, for example, in an automotive chassis, a smaller ball and socket joint may be placed closer to a radiant heat source, for example, a brake disk or brake drum.
In view of the above, it will be seen that the several objects of the invention are achieved and other advantageous results are obtained. As various changes could be made in the above constructions without departing from the scope of the invention, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.
Claims (17)
1. A movable ball and socket joint comprising:
a housing;
a stub shaft having a ball element formed on one end thereof, said ball element seated within said housing; and at least one bearing element interposed between said ball element and said housing, said at least one bearing element formed from a compressed braided wire mesh.
a housing;
a stub shaft having a ball element formed on one end thereof, said ball element seated within said housing; and at least one bearing element interposed between said ball element and said housing, said at least one bearing element formed from a compressed braided wire mesh.
2. The movable ball and socket joint of Claim 1 wherein said at least one bearing element is formed from a ferrous metal wire.
3. The movable ball and socket joint of Claim 1 wherein said at least one bearing element is formed from a non-ferrous metal wire.
4. The movable ball and socket joint of Claim 1 wherein said braided metal wire mesh is compacted to achieve a specified axial and radial stiffness.
5. The movable ball and socket joint of Claim 4 wherein said specified axial and radial stiffness is substantially equivalent to an axial and radial stiffness of an polymer bearing element.
6. The movable ball and socket joint of Claim 1 wherein said at least one bearing element is ring shaped, having an inner radius conforming to an outer surface of said ball element and an outer radius conforming to an inner surface of said housing.
7. The movable ball and socket joint of Claim 1 wherein said at least one bearing element is washer shaped, said at least one bearing element deformable to conform to the an outer surface of said ball element and an inner surface of said housing.
8. The movable ball and socket joint of Claim 1 wherein said at least one bearing element is lubricant permeable.
9. The movable ball and socket joint of Claim 1 wherein said at least one bearing element is resistant to the application of heat.
10. The movable ball and socket joint of Claim 1 wherein said at least one bearing element exerts a preload force on said ball element and accommodates gradual wear of said socket components.
11. A method for manufacturing a braided metal bearing for use in ball and socket applications, comprising the steps of:
inserting a braided wire mesh into a die;
compressing said braided wire mesh within said die to form a desired bearing shape, said desired bearing shape having predetermined axial and radial compliance;
removing said compressed wire mesh bearing from said die.
inserting a braided wire mesh into a die;
compressing said braided wire mesh within said die to form a desired bearing shape, said desired bearing shape having predetermined axial and radial compliance;
removing said compressed wire mesh bearing from said die.
12. The method of Claim 11 for manufacturing said metal bearing further including the step of heating said tubular wire mesh during simultaneous with the compressing of said tubular wire mesh.
13. The method of Claim 11 for manufacturing said metal bearing further including the step of hardening said compressed wire mesh bearing after removal from said die.
14. The method of Claim 13 wherein said hardening step utilizes a conventional gas carborization hardening process.
15. The method of claim 14 wherein said hardening step utilizes a quench and temper hardening technique.
16 16. The method of Claim 11 for manufacturing said metal bearing wherein said braided wire mesh is prehardened.
17. The method of Claim 11 for manufacturing said metal bearing wherein said braided wire mesh is formed from an annealed high-carbon wire.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US72358000A | 2000-11-28 | 2000-11-28 | |
| US09/723,580 | 2000-11-28 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2363866A1 true CA2363866A1 (en) | 2002-05-28 |
Family
ID=24906848
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA 2363866 Abandoned CA2363866A1 (en) | 2000-11-28 | 2001-11-27 | Compliant braided metal bearing for use in bushing application |
Country Status (2)
| Country | Link |
|---|---|
| CA (1) | CA2363866A1 (en) |
| MX (1) | MXPA01012271A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109253166A (en) * | 2018-10-23 | 2019-01-22 | 江苏新风网业有限公司 | A kind of self-lubricating bearing copper mesh and its manufacturing method |
| CN113227590A (en) * | 2019-03-08 | 2021-08-06 | 费德罗-莫格尔汽车配件有限责任公司 | Socket assembly and method for manufacturing socket assembly |
-
2001
- 2001-11-27 CA CA 2363866 patent/CA2363866A1/en not_active Abandoned
- 2001-11-28 MX MXPA01012271 patent/MXPA01012271A/en unknown
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109253166A (en) * | 2018-10-23 | 2019-01-22 | 江苏新风网业有限公司 | A kind of self-lubricating bearing copper mesh and its manufacturing method |
| CN113227590A (en) * | 2019-03-08 | 2021-08-06 | 费德罗-莫格尔汽车配件有限责任公司 | Socket assembly and method for manufacturing socket assembly |
| CN113227590B (en) * | 2019-03-08 | 2024-05-10 | 费德罗-莫格尔汽车配件有限责任公司 | Nest type assembly and manufacturing method thereof |
Also Published As
| Publication number | Publication date |
|---|---|
| MXPA01012271A (en) | 2004-08-12 |
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| Date | Code | Title | Description |
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| FZDE | Dead |