SPRING-LESS METALLIC BALL JOINT

FIELD OF INVENTION

The present invention relates to a spacer for vehicular steering metallic ball joint. Specifically, the present invention relates to a polymeric spacer for the vehicular steering metallic ball joint, and more specifically, a spacer made of polyurethane material or a material with higher elasticity and resistance to permanent set spacer is used in place of a metal spring in the steering ball joint. The spacer of the present invention provides cushioning between top metal bearing and metallic end plate of the steering ball joint, avoiding metal to metal contact and thereby improving noise, vibration and harshness characteristics. Further, the present invention aims at improving the performance and durability of the vehicular steering metallic ball joint.

DESCRIPTION OF PRIOR ART

The steering mechanism in automobiles is provided with a steering ball joint/drag link assembly, which links the drop arm of the steering gear with vehicle's wheel-knuckle arm assembly and tie rod assembly between front wheels steering knuckle, which enables to steer the road wheels based on the rotational motion given by vehicle driver to the steering wheel. This arrangement provides a high wheel steering flexibility. The important requirement of a ball joint, especially those used in automotive steering links is to sustain a long service life. During course of tie rod's/drag link assembly's intended service period, they should not have abnormal free play. Free play is defined as the relative motion developed between the internals of a ball joint when an axial/radial load is applied on the ball pin and when socket is held stationary. Free play, if generated in tie rod's/drag link assembly's, will reduce the response of the steering system, which also will generate vibration in vehicle at higher acceleration/speeds and noise during operation, providing discomfort to the driver and occupants of the vehicle.

A vehicle ball joint consists of sub-components, which are assembled to perform its rotational and articulation functions. The components namely socket housing, ball pin, single or multiple bearing cups with or without application of grease, with or without boot seal, with or without spring, with or without end plate are placed and crimp closed or fastened at a load based on functional requirements to arrest the ball joint from disassociation during vehicle operation.

The ball joint assembly having the said construction has higher wear, which reduces its performance. Inclusion of metal spring in ball joint assembly is to compensate for wear during service period/long run. However, degeneration of mechanical properties of metal spring during service period/long run affects the performance of the steering ball joint. The metal spring need to be manufactured with closer tolerance for parallelism and concentricity. Further usage of metal spring increases noise, vibration and harshness characteristics that is undesirable.

Some of the prior arts are:

US4995755 disclosed a ball joint with numerous cylindrical rollers arranged by a ring-shaped cage placed in between the hemispheric head members. An elastic member is placed between the socket and the ball seat. This construction is complex since it has more number of moving parts.

US4372621 disclosed composite plastics support bearing for the ball pin of a ball and socket joint. The object is to achieve pre-load and support the ball pin by providing a plastics bearing consisting of a hard and soft plastic bearing. The position of soft plastic bearing is in direct contact with rotating part which increases wear on soft plastic due to heat produced during intended usage of ball joint.

GB1033969 provided a ball joint with a housing, a pin, two bearing rings with material such as synthetic plastics and a sleeve with material of homogeneous molded polyurethane. The position of sleeve is in contact with the moving parts and would generate heat which would result in degeneration of sleeve characteristics resulting in higher free play and depreciates its durability. Moreover, the position of the sleeve would restrict articulation angle of ball stud which is significant.

While numerous approaches for making vehicle ball joints are known in the art, there is considerable room for improvement in the field without sacrificing the performance characteristics, which can be easily manufactured. Therefore, there exists a need for improving the vehicle ball joint performance that is the internal construction to be modified accordingly, which enhances the characteristics of ball joint like enhanced performance, increased durability and reduction of cost.

OBJECTS OF INVENTION

The primary object of the present invention is to improve performance and durability of the vehicular steering metallic ball joint.

A further object of the present invention is to enhance the performance by achieving consistency in torque and free play/rigidity.

It is yet another object of the present invention, wherein a spacer made of polyurethane material or a material with higher elasticity and resistance to permanent set is used in the vehicular steering metallic ball joint for an automotive steering linkage.

It is another object of the present invention, wherein the spacer is used in place of a spring/metal spring in the vehicular steering ball joint.

It is another object of the present invention, wherein the spacer provides cushioning between top metal bearing and metallic end plate of the steering ball joint, avoiding metal to metal contact and thereby improving noise, vibration and harshness characteristics.

It is another object of the present invention, wherein construction/design of the spacer is of ring type.

It is another object of the present invention to provide steering ball joint without metal spring to seat either
a single bearing cup construction or two bearing cup construction for the vehicle steering ball joint.

It is another object of the present invention, wherein the spacer eliminates phenomena of permanent set which is prevalent with metal spring and which as observed in prior art is more prone to decay of mechanical properties in spring like spring rating decay in long run or intended service period.

It is another object of the present invention wherein the simple construction of the spacer aids for manufacturability and inspection accumulates to reduction in cost.

SUMMARY OF INVENTION

Thus according to the basic aspect of the present invention there is provided a vehicle steering metallic ball joint with polyurethane spacer having improved noise, vibration and harshness characteristics.

In another aspect of the present invention, there is provided a vehicle steering metallic ball joint comprising spacer made of a material with higher elasticity and resistance to permanent set and thereby having improved noise, vibration and harshness characteristics.

Another aspect of the present invention is directed to provide a vehicle steering metallic ball joint comprising:

socket housing with stem with or without grease nipple provision;

atleast one ball pin with a spherical head disposed in the socket housing;

atleast one metallic bearing cup disposed there between the ball pin with the spherical head and the socket housing; and
spacer,

wherein the spacer is of polyurethane spacer or made of a material with higher elasticity and resistance to permanent set.

It is another aspect of the present invention, wherein the spacer is positioned between top metallic bearing cup and an end plate thereby avoiding metal to metal contact.

It is another aspect of the present invention, wherein the spacer is used in place of a conventional metal spring thereby eliminating phenomena of permanent set prevalent in the metal spring.

It is another aspect of the present invention, wherein the spacer is of ring type construction.
It is another aspect of the present invention, wherein height of the ring type spacer is less when compared to uncompressed spring.

It is another aspect of the present invention, wherein the spacer is protruded from the top metallic bearing cup, and the said protrusion is ~1mm.

BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1: Illustrates a conventional ball and socket joint.

Figure 2: Illustrates a metallic ball and socket joint according to the present invention.

DETAILED DESCRIPTION OF THE INVENTION WITH REFERENCE TO THE ACCOMPANYING DRAWINGS

As disclosed above, the present invention relates to the use of polymeric spacer, specifically a spacer made of polyurethane material or a material with higher elasticity and resistance to permanent set spacer in place of conventional metallic spring. The spacer provides cushioning between top metal bearing and metallic end plate of the steering ball joint, avoiding metal to metal contact and thereby improving noise, vibration and harshness characteristics.

With reference to Figure 1, conventional ball and socket joint comprises of a socket housing (1) with a stem (2) for engagement with steering linkage (not shown), a ball pin (3) with a spherical head (4) encapsulated in top metallic bearing cup (6) and the socket housing (1) and a metallic spring (5) is placed between the top metallic bearing cup (6) and end plate (7). All internal components are placed and crimp closed (8) at a load based on functional requirements to arrest the ball joint from disassociation during vehicle operation. A boot seal (9) is mounted on the socket housing (1) encapsulating ball pin head and preventing entry of contaminants.

With reference to Figure 2, a vehicle steering metallic ball joint of present invention comprises of socket housing (1) connected to a steering linkage (not shown) through a stem (2) either through thread or groove for heat clamping arrangement and with or without grease nipple provision, a ball pin (3) with a spherical head (4) encapsulated in top metallic bearing cup (6) and the socket housing (1) and a spacer made of polyurethane material or a material with higher elasticity and resistance to permanent set of ring type is used in place of a conventional metallic spring (5) and is positioned between the top metallic bearing cup (6) and end plate (7). The height of the ring type spacer (10) is less when compared to uncompressed spring which enables the spacer (10) to get accommodated inside the relief of the top metallic bearing cup (6) resulting in a near flush fit inside the top metallic bearing cup (6) thereby reducing the overall height of socket housing. The end plate (7) is with or without grease nipple provision and roll peened by the socket housing (1) to secure the components from disassociation. AH internal components are placed and crimp closed (8) at a load based on functional requirements to arrest the ball joint from disassociation during vehicle operation. A boot seal (9) is mounted on the socket housing (1) encapsulating ball pin head and preventing entry of contaminants. The protrusion of the spacer (10) from the top metallic bearing cup (6) is ~lmm when compared to ~ 10 mm in ball joints were metallic springs are accommodated thereby resulting in cost saving. Thus according to the present invention, the arrangement of spacer reduces complexity, improves durability, provides cushioning effect, avoids metal to metal contact and thereby improves noise, vibration and harshness characteristics.

WE CLAIM:

1. A vehicle steering metallic ball joint with polyurethane spacer (10) having improved noise, vibration and harshness characteristics.

2. A vehicle steering metallic ball joint comprising spacer (10) made of a material with higher elasticity and resistance to permanent set and thereby having improved noise, vibration and harshness characteristics.

3. The ball joint as claimed in claims 1 and 2 comprising:
socket housing (1) with stem (2);

atleast one ball pin (3) with a spherical head (4) disposed in the socket housing (1);

atleast one metallic bearing cup disposed there between the ball pin (3) with the spherical head (4) and the socket housing (1); and
spacer (10),

wherein the spacer (10) is of polyurethane spacer or made of a material with higher elasticity and resistance to permanent set.

4. The ball joint as claimed in claim 3, wherein the spacer (10) is positioned between top metallic bearing cup (6) and an end plate (7) thereby avoiding metal to metal contact.

5. The ball joint as claimed in claim 4, wherein the spacer (10) is used in place of a conventional metal spring thereby eliminating phenomena of permanent set prevalent in the metal spring.

6. The ball joint as claimed in claim 5, wherein the spacer (10) is of ring type construction.

7. The ball joint as claimed in claim 6, wherein height of the ring type polyurethane spacer (10) is less when compared to uncompressed spring.

8. The ball joint as claimed in claim 7, wherein the spacer (10) is protruded from the top metallic bearing cup (6), and the said protrusion is ~1mm.