FIELD OF INVENTION

The present invention relates to an automobile steering ball joint including Inner Tie Rod (ITR) and Outer Tie Rod (OTR) in a steering linkage. More particularly the invention relates to the anti-wear and/or anti-friction layer that is applied to such ball joint internal mating interfaces by spray or dip and spin coating or layer adhesion or assembly fit over base material member which provide resistance to wear in operation, thereby ensuring the ball joints that are fitted onto vehicles have improved life during service. Thus the present invention relates to anti-friction layer coating or adhesion or assembly fit on ball stud head/ spherical surface periphery and assembled onto the mating part with or without grease lubrication applied at the mating conjunction, which is there by assembled onto the socket housing with or without a contaminant protecting cover.

DESCRIPTION OF PRIOR ART

A ball joint consists of sub-components, which are assembled to perform its rotational and articulation functions. Constituent components namely: socket housing, ball stud, single or multiple bearing cups, with or without boot seal, with or without end plate are placed and crimp closed at a load based on functional requirements to arrest the ball joint from disassociation during vehicle operation. The single or multiple bearing cups is under constant load and contact with the static/dynamic conditions of ball pin. Under its normal operation the bearing cup's surface is degraded due to wear by friction. The initial wear period is the key determinant for life of a ball joint. (Lower initial wear period reduces the life of ball joint). Maximizing the initial wear period at the bearing cup and its mating part conjunction, by enhancing the significant mechanical properties, improves the life of a ball joint.

The properties of the material used in the manufacturing of any conventional ball joint directly relates to the rate of wear of the bearing within the ball joint assembly impacting the life of the ball joint assembly and the requirement for periodic replacement of the ball joint assembly for effective functioning of the steering. Due to wear in the bearing members, clearance within the internal components is generated and consequently the rotating and swiveling torque values are also reduced generating vibration and noise in vehicle at higher acceleration/speeds, providing discomfort to the driver. The more frequent replacement increases the cost of maintaining the automobile significantly.

US 20080008520 discloses an automotive ball joint assembly with Nickel-Boron coating applied to the outer surface of the spherical member to protect the spherical member against wear from friction, impact and corrosion. JP 2006250206 relates to an amorphous carbon hard coating to improve the coefficient of dynamic sliding friction formed on the rolling surfaces (ie the inner and outer race surface). The ball is free of coating and the ball slides over the coated surfaces to improve the coefficient of sliding friction. JP 2000145753 is directed to a vehicular joint assembly having a high load bearing capability and improved performance, by providing two basic parts including a dual axis part bar-pin journal and an elastomer bearing socket to be eternally lubricated and sealed throughout the life. FR 2791100 deals with low friction coating on the recess of a plate where the joint ball is in permanent contact.

KR 20000042021 is directed to a ball joint coated with grease to form a lubricant on the outer diameter of the ball inserted to a circular recessed groove of a ball seat of a gas spring to prevent friction occurring in the rotation of a ball joint.

JP 2076969 deals with a method of improving lubricity between a ball body and a lock member and increasing reliability of a ball joint piston Therefore, there exists a need for improving the product performance in field operation by deposition of a coating, which enhances the characteristics of ball joint like: 1. Well balanced mechanical properties

2. Internal surface protection over environmental contaminants

3. High wear and friction resistance

4. Improved service life

OBJECTS OF THE PRESENT INVENTION

One or more of the problems of the conventional prior art may be overcome by various embodiments of the system and method of the present invention.

Accordingly the primary object of the present invention is to provide for an anti-wear and/or anti-friction coating to an automobile steering ball joint/Outer Tie Rod (OTR) in a steering linkage.

It is another object of the present invention to provide for a ball joint which can resist wear and tear on operation wherein an unconventional coating on ball stud spherical head with an antifriction coating to enhance the wear properties is provided, thereby ensuring the ball joints that are fitted onto vehicles has improved life during its service.

It is yet another object of the present invention to provide for an anti-wear and/or antifriction coating on ball stud head/ spherical surface periphery and assembled onto the mating part with or without grease lubrication applied at the mating conjunction, which is there by assembled onto the socket housing with or without a contaminant protecting cover.

SUMMARY OF THE INVENTION

Thus according to the basic aspect of the present invention there is provided a ball joint comprising:

a housing;

a ball socket;

atleast one bearing disposed within said housing; atleast one ball stud disposed in the ball socket comprising one or more elongated solid/hollow shaft portion and a spherical head portion provided in an end portion of said shaft; and

a ceramic/fibrous/polymer layer of coating material is applied to the said spherical head outer surfaces and maybe including at least one of said bearing inner surface to protect said surfaces against wear from friction, impact and corrosion,

wherein said bearing having an inner surface,

wherein said spherical head portion having an outer surface in contact with the inner surface of said bearing, whereby said ball stud may rotate or otherwise move with respect to said bearing,

wherein said ball stud avoids dis-association of the joint and enables to perform intended articulation or rotational functions, and

wherein said anti-friction coating on said ball stud head spherical surface periphery are assembled onto the mating part with or without grease lubrication applied at the mating conjunction, which is there by assembled onto said socket housing with or without a contaminant protecting cover.

In accordance with another aspect of the present invention there is provided a ball joint wherein said anti-wear and/or anti-friction material is adhesively bonded with the base material of said ball stud member. hi accordance with another aspect of the present invention there is provided a ball joint, wherein said anti-wear and/or anti-friction material is injection/compression molded over the base material of said ball stud member. In accordance with another aspect of the present invention there is provided a ball joint, wherein a separate ceramic/fibrous/polymer spherical ball of anti-wear and/or antifriction material is assembled over the base material of said ball stud member with or without bonding agents. hi accordance with another aspect of the present invention there is provided a ball joint, wherein said articulation or rotational functions is performed at the axis and extreme ends of said ball stud in non-automotive/ automotive suspension or steering linkage ball joint applications.

A further aspect of the present invention relates to a ball joint, wherein metal closure over the outer periphery without end plug arrests said ball stud from protruding in horizontal directions.

A further aspect of the present invention relates to a ball joint, wherein metal closure over the outer periphery with or without end plug arrests said ball stud from protruding in vertical directions.

The details of the invention, its objects and advantages are explained hereunder in greater detail in relation to non-limiting exemplary illustrations as per the following accompanying figures: BRIEF DESCRIPTION OF THE ACCOMPANYING FIGRURES

Figure 1 : illustrates a cross-sectional view of a ball joint assembly in accordance with the present invention.

Figure 2: illustrates the anti-friction coating on the outer ball joint, inner ball joint of the preferred embodiment. Figure 3: illustrates the anti-friction coating on the on the spherical head portion of the ball stud.

Figure 4: illustrates the anti-friction coating on the spherical portion of the ball stud and extended through the said elongated shank portion excluding the threaded portion.

Figure 5: illustrates the rotation of ball stud in its own axis. Figure 6: illustrates the articulation of ball stud to extreme ends.

Figure 7: illustrates the metal closure of ball joint in horizontal direction.

Figure 8: illustrates the metal closure of ball joint in vertical direction. DETAILED DESCRIPTION OF THE INVENTION WITH REFERENCE TO THE ACCOMPANYING FIGURES:

This present invention relates to an automobile steering ball joint including Inner Tie Rod (ITR) and Outer Tie Rod (OTR) in a steering linkage. More particularly the invention relates to the anti-wear and/or anti-friction coating that is applied to such ball joint internal mating interfaces which provide resistance to corrosion, wear in operation, thereby ensuring the ball joints that are fitted onto vehicles have improved life during service.

Ball joints are the pivot between the wheels and the steering and suspension of an automobile. Ball joints play a critical role in the safe operation of an automobile's steering and suspension. A ball joint is typically used to interconnect relatively movable parts of a steering linkage or a suspension of an automotive vehicle. It will be apparent that the ball joint may also be used in an automobile suspension or in other applications.

Reference is first invited to Figure 1, which illustrates a ball joint assembly (1) constructed in accordance with the present invention. The ball joint assembly (1) includes a ball stud member (3) engaged with a bearing (6). The ball stud member (3) and bearing (6) are captured within a socket housing (2). The housing (2) is arranged around the bearing (6) such that the bearing is fixed with respect to the housing (2). The ball stud member has a spherical head portion (4) and a shaft portion (5).

The ball stud member (3) is positioned within the bearing (6) such that an outer surface (4a) of the spherical head (4) of the ball stud member (3) is in contact with an inner surface (6a) of the bearing (6), whereby the ball stud (3) may rotate or otherwise move with respect to the bearing (6). In the exemplary embodiment, the shaft portion (5) extends from the spherical head (4) of the ball stud member (3) defines a longitudinal axis (7), a threaded portion (8) extending outwardly from the respective housing (5) to which additional components or structures may be coupled. The shaft (5) provides for the motion of the ball stud (3) to be transferred to components or structure coupled to the shaft (5). For example, in an exemplary automotive application, the stud (3) may be coupled to a steering knuckle and the housing (2) may be coupled to a control arm. Another example is a steering outer tie rod assembly wherein the stud member (3) may be coupled to a steering knuckle and the housing (2) may be coupled to the inner tie rod of steering gear. Other examples include single and double suspension linkage assemblies wherein the ball stud (3) couples to the knuckle and the housing (2) couples with the linkage. A boot (9) is secured between the ball stud (3) and the housing (2) to protect the ball joint (1) from grit and other contamination.

Further the embodiment shows a portion of the link (10) preferably tubular, prior to the ball joint assembly. The link (10) comprises an end that includes a spanner hold flat surface which provides an irregular shape.

Accompanying Figures 1 and 2 shows a relatively thin coating (11) applied to the outer surface (4a) of the ball stud (3). In the exemplary embodiment, the

Ceramic/Fibrous/Polymer layer is deposited on the ball stud formed on the spherical head portion (4). The outer layer is formed by external adhesion of a layer, coating by spray/dip and spin process or by moulding wherein the moulding can be injection/compression type over the base of the spherical head of the ball stud. A lubricating substance may be disposed between the outer surface (4a) of the ball stud spherical head (4) and the inner surface (6a) of the bearing (6).

Figure 3 shows ceramic/polymer/fibrous layer of anti-wear and/or anti-friction material coating (11) on the spherical head portion (4) of the ball stud (3) and Figure 4 shows ceramic/polymer/fibrous layer of anti-wear and/or anti-friction material (11) on the entire portion of the ball stud (3) excluding the threaded portion.

The ball stud is manufactured or fabricated from steel and the spherical head portion is manufactured or fabricated from ceramic or fiber or polymer and the exemplary bearing is manufactured or fabricated from a polymeric material. However, other known materials may be used. Moreover, the present invention describes a ball joint assembly that includes a ball stud coated with a Ceramic/Fibrous/Polymer layer.

Accordingly, the present invention is fabricated to suit the mating requirement, with or without grease and with or without an end plug which is crimped over and closed to avoid dis-association of the joint, and with or with-out boot seal construction to perform the intended articulation or rotational functions.

Moreover the ceramic/polymer/fibrous layer of anti-wear and/or anti-friction material could be adhesively bonded with the base material of the ball stud member. Advantageously, the coating could be done, where a separate polymer/fibrous spherical ball of anti-wear and/or anti-friction material could be assembled over the base material of the ball stud member with or without bonding agents.

In accordance with the further aspect of the invention, provided Ceramic/Fibrous/Polymer layer of anti-friction coating (11) on the spherical head portion (4) of the ball stud member (3) and assembled onto the mating part with or without grease lubrication applied at the mating conjunction, which is there by assembled onto the socket housing (2) with or without a contaminant protecting cover.

The Ceramic/Fibrous/Polymer coating is a form of non metallic coating which offers a number of properties and features that can extend the service life of a ball bearing joint. Polymer coatings include the binders used to formulate coating and adhesives. The polymer coating resin can be solvent or water based, or applied as a 100% solid, such as powder coatings or radiation cured coatings. Adhesive materials are formulated to give desired adhesive and tack properties, and resistance to temperature and fluids. Ceramic coatings are non-metallic materials that include carbides, nitrides, borides and suicides that are processed and used at high temperatures. The characteristics of ceramic coating include wear and abrasion resistant, low friction, high hardness, anti-reflective, corrosion resistant and slows diffusion rate. Advantageously deposition of an antifriction coating enhances the wear properties. This provides resistance to wear on operation, thereby ensuring the outer tie rods that are fitted onto field vehicles have improved life during its service. In addition these coatings offer well balanced mechanical properties, high wear and friction resistance life.

Figure 5 illustrates that the rotational functions are performed at its own axis of ball stud

(with or without boot) in non-automotive / automotive suspension or steering linkage ball joint applications. Figure 6 illustrates that the articulation functions are performed at the extreme ends of ball stud (with or without boot) in non-automotive / automotive suspension or steering linkage ball joint applications.

Figure 7 illustrates metal closure over the outer periphery without end plug that arrests the ball stud from protruding in horizontal directions. Figure 8 illustrates metal closure over the end cap that arrests the ball stud from protruding in vertical directions.

It is thus possible by way of the present invention to obtain an automobile steering ball joint including Inner Tie Rod (ITR) and Outer Tie Rod (OTR) in a steering linkage with Ceramic/Fibrous/Polymer layer of anti-wear and/or anti-friction material applied to such ball joint internal mating interfaces which provide resistance to wear in operation, thereby ensuring the ball joints that are fitted onto vehicles have improved life during service.