SINGLE BEARING CUP FOR OUTER TIE RODS FIELD OF INVENTION

The present invention relates to single bearing cup for an automobile steering ball joint/outer tie rod (OTR) in a steering linkage. Specifically, the invention relates to a single bearing cup for the OTR with grooves. More particularly, the invention relates to a single bearing cup for the OTR with one or more grooves on the bearing cup inner or outer profile and with or without one or more grooves on top surface of the bearing cup. Advantageously, the present invention facilitates for 100% leak check on ball joints for production volumes at non-destructive level/ an unrestricted passage for leak check on ball joints by both destructive and non-destructive level.

DESCRIPTION OF PRIOR ART

An automobile steering ball joint/ OTR is a steering linkage, which links the steering gear with vehicle wheel-knuckle arm assembly, to steer the road wheels based on the rotational motion given by vehicle driver on the steering wheel. During course of OTRs intended service period, they are not to have free play. Free play, if generated in OTRs, reduces the response of the steering system. It also generates vibration in vehicle at higher acceleration/speeds and noise during its vehicle operation, providing discomfort to the driver. Free play is described as "Elasticity or lash > 0.1 mm when measured applying a load of IN"

An OTR consists of sub-components, which are assembled to perform its rotational and articulation functions. Constituent components namely: socket housing , ball pin, single bearing cup/mono-lube cup, boot seal, end plate are placed and crimp closed over the end plug at a load based on functional requirements to arrest the OTR from disassociation during vehicle operation.

One of the most important requirements of a ball joint, especially those used in automotive steering links is to maintain for a long service life. Normally, one of the prime factors that reduce life of the ball joint is ingress of various contaminants resulting in excess wear. One of the contributing factors is improper sealing at end plate crimp closure.

Currently ball joints with two bearing cup construction are subjected to destructive level sampling check on production quantities to ensure the effectiveness of the crimp closure. Being sampling check, the assurance of 100% leak proof ball joint not possible. A hole drilled through the end plate of the ball joint is connected to an external air supply and immersed in a liquid medium to evaluate the effectiveness of crimp closure. Ineffective crimp closure results in generation of bubbles in liquid medium, thereby indicating a leaky ball joint. Corrective action will be placed only if a part is rejected for leak during sampling. This generates huge quantity of non-useable ball joints which are to be scrapped off. This loss of product is accounted to the loss to company.

Moreover, single bearing cup design does not include any grooved passage provided on its inner/outer profiles and top surfaces and does not facilitate an unrestricted passage for leak check on ball joints by both destructive and non-destructive level.

Some attempts have been made in the past to deal with overcoming the stated limitations of the prior art such as those disclosed in the following:

US 6488436 relates to ball joint, and a method of making the ball joint with a ruptured zig zag zones on single bearing molded cup.

US 5116159 disclose a ball and socket joint assembly with two bearing cup construction. It relates to an improved preload system in which a relatively consistent torque may be achieved in spite of substantial tolerance variations in initial dimensions of the assembled parts.

US 3950006 relates to rack and pinion steering gear assembly with two bearing cup design for tie rods.

GB 2108196 disclose a ball and socket joint having a cup shaped socket formed from a tubular member, the bearing cup located in the socket and a ball pin is a one piece cup supporting the ball on both sides of an equator E-E thereof, whereas the present invention relates to the construction of the flanged type single bearing cup with grooves.

EP0075414 relates to ball and socket joints for use on motor vehicle steering and suspension systems. The bearing cup is surrounded by a compressed elastomeric bush that surrounds the cup in equatorial region (E-E) of the head to bias the cup against the head to exert a torque load thereon. Moreover the two bearing cups are split at half around the equator with slots incorporated with outwardly projecting flange. The present invention directs to a single bearing cup construction in ball joints with grooves that facilitate the assessment of sealing effectiveness, on the crimp closure over the end plug by a non-destructive level leak check.

GB 1566757 disclose a ball and socket joint having a substantially cup shaped housing which is lined by a bearing socket in which the ball of the ball pin is rotatable, the socket being a snap-fit on the ball of the ball pin so as to support said ball on both sides of an equator normal to the polar axis constituted by the longitudinal axis of the cup shaped housing. The present invention relates to a single bearing cup for the OTR with one or more grooves on the bearing cup inner or outer profile and with or without one or more grooves on top surface of the bearing cup.

Therefore a need exists to provide a single bearing cup for the OTR with grooves on the bearing cup inner or outer profile that facilitates for 100% leak check on ball joints for production volumes at non-destructive level.

OBJECTS OF THE INVENTION

The basic object of the present invention is thus directed to provide for a single bearing cup for an automobile steering ball joint/outer tie rod (OTR) in a steering linkage.
Another object of the present invention is directed to provide for a single bearing cup with one or more grooves on the bearing cup inner or outer profile and with or without one or more grooves on top surface of the bearing cup.

It is another object of the present invention wherein the top grooves are positioned mid-way between the inner slit-grooves, to ensure there is no deterioration in strength and reduce the wall thickness.

It is yet another object of the present invention wherein the groove on inner profile merges with bearing slits to have maximum contact area for operation.

A further object of the invention wherein the top grooves on the outer profile comes in contact with end plug paper on assembly.

A still further object of the present invention is directed to provide for a single bearing cup construction in ball joints that facilitates the assessment of sealing effectiveness, on the crimp closure over the end plug by a non-destructive level leak check.

It is another object of the present invention to provide for single bearing cup which ensures that all the OTRs fitted onto field vehicles are arrested from water/contaminant ingress through the crimp closure during its service period.

It is yet another object of the present invention to provide for single bearing cup that facilitates for non-destructive level 100% leak check on production volumes.

SUMMARY OF THE INVENTION

Thus according to the basic aspect of the present invention there is provided a single bearing cup for an automobile steering ball joint/outer tie rod (OTR) comprising:
bearing flange; air vent; atleast one slit; and one or more grooves, wherein said bearing cup has an opened end and closed end(top surface), wherein said closed end (top surface) of the cup is profiled to house the end plate of the ball joint, wherein said air vent is positioned at the centre of closed end of the said bearing cup, wherein said slit (s) are provided around the cylindrical circumference (body) of the said bearing cup, wherein said groove (s) are provided on the outer surface of the closed end of the said bearing cup, wherein said groove (s) are provided on the inner surface of the closed end and body of the said bearing cup, and wherein said bearing cup is with flange.

Another aspect of the present invention is directed to a single bearing cup, wherein said air vent is a hole whose diameter is less than at its equator on the opposite end to engulf the spherical head of the ball pin with or without lubrication at the mating surfaces.
In the above said invention, wherein said bearing flange is absent.

It is further aspect of the present invention, wherein said groove (s) are absent.

A further aspect of the present invention is directed to a single bearing cup, wherein said slit (s) (7) extends towards the equator and finishes just above the equator to support opening and closure of the bearing.

A still further aspect of the present invention is directed to a single bearing cup, wherein said groove (s) (8) on the top tapered surface are at the midway of the inner profile slit-groove arrangement.

According to another aspect of the present invention, said groove (s) (8) on the inner surface overlap with the said slit (s).

According to another aspect of the present invention, the said bearing cup has step cylindrical profile to rest the bearing.

It is another aspect of the present invention, wherein said end plate rests on the outer profile which may or may not be in contact with the flange surface of the said bearing.
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 DRAWINGS

Figure 1: illustrates single bearing cup without grooves existing in the prior art.

Figure 2: illustrates a cross-sectional view of a ball joint assembly in accordance with the present invention.

Figure 3and 4: illustrates monolube /single bearing cup with grooves in accordance with the present invention.

DETAILED DESCRIPTION OF THE INVENTION WITH REFERENCE TO THE ACCOMPANYING DRAWINGS

As already described, the invention is directed towards a single bearing cup for the outer tie rod (OTR) with grooves on the bearing cup inner or outer profile that facilitates for 100% leak check on ball joints for production volumes at non-destructive level.
Reference is first invited to Figure 1 that illustrates single bearing cup existing in the prior art. It does not include any grooved passage provided on its inner/outer profiles and top surfaces and does not facilitate an unrestricted passage for leak check on ball joints by both destructive and non-destructive level.

Reference is now invited to Figure 2 that illustrates a cross-sectional view of a ball joint in accordance with the present invention. The ball joint assembly (1) includes a ball stud (2) engaged with outer profile as a cylindrical single bearing cup (3) with or without flange which is fully covered at one end and has a spherical internal profile with a circular opening having a reduced diameter than at its equator on the opposite end to engulf the spherical head (6) of the ball stud (2) with or without lubrication at the mating surfaces. The ball stud (2) and single bearing/ monolube cup (3) are captured within a socket housing (4). The socket housing (4) seats the bearing (3) along with the ball stud (2) having stepped cylindrical internal profile to rest the bearing. Accordingly, the present invention is fabricated with an end plug /end plate (5) 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. The end plug (5) resting on the tapered outer profile may or may not be in contact over the flanged surface of the bearing.

Reference is then invited to Figures 3 and 4 that illustrates single bearing cup of the present invention.

The single bearing cup (3) has an opened end and closed end (top surface) (11), with air vent at (10) the centre of this closure. The air vent is a hole whose diameter is less than at its equator on the opposite end to engulf the spherical head (6) of the ball pin (2) with or without lubrication at the mating surfaces. The bearing cup has atleast one slit (7) around its cylindrical circumference beginning from opposite side to the tapered face at the mouth diameter and is extending towards the equator and finishes just above the equator to support opening and closure of the bearing when ball pin / ball stud (2) is press fitted and assembled over the housing bore which seats the bearings. The bearing has one or more grooves (8) along the inner spherical profile which may or may not coincide with the slits of the bearing and is extended to the opposite end to join with the air vent hole. When the grooves (8) on inner profile merge with bearing slits it has maximum contact area for operation. Additionally, the bearing has one or more grooves on the tapered outer top profile extending from the air-vent hole (10) and towards the flanged surface of the bearing (9). The grooves on the top tapered surface are at the midway of the inner profile slit-groove arrangement to ensure there is no deterioration in strength and reduce the wall thickness.

Moreover, the top grooves on the outer profile come in contact with end plug tapered on assembly.
Advantageously, the present invention facilitates the assessment of sealing effectiveness, on the crimp closure over the end plug by a non-destructive level leak check. It ensures that all the OTRs fitted onto field vehicles are arrested from water/contaminant ingress through the crimp closure during its service period. Moreover, it facilitates for non-destructive level 100% leak check on production volumes.

WE CLAIM:

1. A single bearing cup (3) for an automobile steering ball joint/outer tie rod (OTR)
comprising:

bearing flange (9);

air vent (10);

atleast one slit (7); and

one or more grooves (8),

wherein said bearing cup has an opened end and closed end (top surface) (11),
wherein said closed end (top surface) of the cup is profiled to house the end plate (5) of
the ball joint (1),

wherein said air vent (10) is positioned at the centre of closed end of the said bearing cup,
wherein said slit (s) (7) are provided around the cylindrical circumference (body) of the
said bearing cup,

wherein said groove (s) (8) are provided on the outer surface of the closed end of the said
bearing cup,

wherein said groove (s) are provided on the inner surface of the closed end and body of
the said bearing cup, and

wherein said bearing cup is provided with flange (9).

2. A single bearing cup as claimed in claim 1, wherein said air vent (10) is a hole whose
diameter is less than at its equator on the opposite end to engulf the spherical head (6) of
the ball pin (2) with or without lubrication at the mating surfaces.

3. A single bearing cup as claimed in claim 1, wherein said bearing flange (9) is absent.

4. A single bearing cup as claimed in claim 1, wherein said groove (s) (8) are absent.

5. A single bearing cup as claimed in claim 1, wherein said slit (s) (7) extends towards the equator and finishes just above the equator to support opening and closure of the bearing.

6. A single bearing cup as claimed in claim 1, wherein said groove (s) (8) on the top tapered surface are at the midway of the inner profile slit-groove arrangement.

7. A single bearing cup as claimed in claims 1 and 6, wherein said groove (s) (8) on the inner surface overlap with the said slit (s).

8. A single bearing cup as claimed in anyone of claims 1 to 7, wherein said bearing cup has step cylindrical profile to rest the bearing.

9. A single bearing cup as claimed in claim 1, wherein said end plate (5) rests on the outer profile which may or may not be in contact with the flange surface of the said bearing.