KINGPIN ARRANGEMENT FOR NON-DRIVE STEERABLE AXLE OF A MOTOR VEHICLE
FIELD OF THE INVENTION:
[001] This invention relates to non-drive steerable axle kingpin arrangement for a motor vehicle. More particularly, the kingpin arrangement for enabling axle arm fitted with road wheel assembly to swivel with respect to kingpin component with the help of bearing elements positioned between axle arm and kingpin component. BACKGROUND OF THE INVENTION:
[002] Figure 1 illustrates a conventional kingpin arrangement consists of axle beam (a), axle arm (b), bushes (c, d), shims (e), thrust bearing (f), cotter pins (g), cover plate (h, i) with grease nipple (j, k), cover plate gasket (1, m) and seals (n, o). Kingpin component is made up of uniform diameter over entire length provided with two slots transversely to physically interact with cotter pins (g). Axle beam (a) have through bore of uniform diameter and with two transverse holes to accommodate kingpin component and cotter pins respectively. Kingpin bushes are pressed in Axle arm's top jaw and bottom jaw. Top Seal is positioned at bottom portion of top jaw and bottom seal is at upper portion of bottom jaw.
[003] Kingpin component is rigidly held in axle beam with cotter pins. Conventional thrust bearing is positioned between the axle beam bottom face and axle arm bottom jaw top surface, absorbs axial forces. Shims used between the bottom surface of axle arm top jaw and axle beam top surface. Top and bottom ends of the kingpin component are covered with cover plates and gaskets. Grease nipple on cover plate is provided for lubricating the kingpin arrangement.

[004] In conventional kingpin arrangement, axle arm swivels with respect to kingpin via bushes and thrust bearing. Thrust bearing absorbs axial forces whereas radial forces are absorbed by bushes. Kingpin component play setting is done with shims, thickness of shim and depends upon the geometrical tolerances of assembly, hence manufacturing plant to maintain multiple numbers of shims with different thickness grades that are provided based on total tolerance range of kingpin assembly. Improper selection of shims leads to excessive preload or negative preload (clearance) of kingpin assembly. High level of pre-load in the system requires heavy force to turn the road wheels which necessitates need of high capacity steering gear box. Kingpin arrangement with negative preload leads to risk of vibration. So the conventional kingpin arrangement needs more attention of operator for shim selection during assembly.
[005] Limitations of conventional kingpin arrangement are (i) system operates in end-play which is not a desirable, (ii) kingpin axial play adjusted by use of shims, (iii) axial play adjustment at manufacturing plant is a complicated and tedious process, (iv) Radial play always exists between kingpin and axle arm bush which cannot be adjusted due to limitations leading to non-uniform wear of bushes. Further, conventional kingpin arrangement calls for periodic lubrication. Over a period of vehicle use with conventional kingpin arrangement typically require replacement of kingpin, bushes, seals, cover plate gaskets, and cotter pins leading to downtime of a vehicle from its operation. More-often axle beam kingpin bore gets oblong due to endplay in the system calls for re-boring to higher diameter which again necessitates the need of oversized kingpin kits. This system builds inventory due to the need

of multiple shims and oversized kingpin kits. Conventional kingpin arrangement provides high rotational resistance of axle arm with respect to kingpin.
[006] There is a long felt need for a kingpin arrangement to provide low rotational resistance of axle arm with respect to kingpin addressing all the limitations of conventional kingpin arrangement and to provide longer useful life of components (maintenance free) .
OBJECT OF THE INVENTION:
[007] The main objective of this invention is to design a kingpin arrangement that works under preloaded condition with low rotational resistance of axle arm with respect to kingpin.
[008] Another objective of this invention is to produce a kingpin arrangement that provides a longer service life of components.
[009] Yet another objective of this invention is to produce a kingpin arrangement that eliminates the tedious process of shim selection, endplay setting and end play measurement during manufacturing of non-drive steerable axle.
[010] Yet another objective of this invention is to produce a maintenance free kingpin arrangement to eliminate periodic lubrication and periodic servicing of parts.
[011] Above objective is achieved by means of taper kingpin arrangement wherein the kingpin component is rigidly secured in axle beam due to existence of taper at kingpin middle portion and a taper bore in axle beam. Specially designed heavy-duty taper roller bearing is positioned in a kingpin arrangement such a way that it takes both axial and radial

load. The taper roller bearing which is filled with high quality grease packed for its service life and it is sealed with dual seal pack design. Integrated seal pack with bearing race is provided for easy assembly and robust sealing requirements. The angular contact toroidal bearing absorbs radial load and takes care of mis-alignment of the entire kingpin arrangement. The angular toroidal bearing is designed to have point of contact to reduce rotational resistance of axle arm thereby reduces the steering effort and improves self-centering of a vehicle after negotiating a turn. The angular contact toroidal bearing is filled with high quality grease packed and sealed for service life. Since both the bearings are pre-lubricated, and sealed for service life, re-lubrication and frequent maintenance are eliminated.
SUMMARY OF THE INVENTION:
[012] In one aspect, an embodiment herein provides a system for non-drive steerable axles of a vehicle. The system includes a kingpin component, an axle beam, an axle arm sub¬assembly, an axle arm. The kingpin component comprising an upper portion, a lower portion and a middle portion. The configuration of the middle portion is in taper design. The axle beam having a taper bore for accommodating the kingpin component. The axle arm sub-assembly having a taper roller bearing and an angular contact toroidal bearing. The bores of the taper roller bearing and the angular contact toroidal bearing are aligned with the taper bore to ensure ingress of the kingpin component via the axle beam. [013] The axle arm is part of axle arm sub-assembly. The axle arm comprises an upper arm and a lower arm for accommodating the axle beam. The upper arm swivels around the upper portion of the kingpin component via said taper roller bearing and said lower arm swivels

around the lower portion of the kingpin component via said angular contact toroidal bearing during an operation of the vehicle.
[014] In another aspect, an embodiment herein provides a method of assembling a system for non-drive steerable axles of a vehicle. The method comprising the steps of: (i) positioning an axle arm sub-assembly over an axle beam; (ii) positioning an upper arm and a bottom arm of the axle arm axially at a predetermined distance to accommodate an axle beam; (iii) inserting a kingpin component via taper bore of the axle beam; (iv) positioning a taper roller bearing in the upper arm of the axle arm to enable the upper arm swivels around an upper portion of the kingpin component; and (v) positioning an angular contact toroidal bearing in the bottom arm of the axle arm to enable the lower arm swivels around a lower portion of the kingpin component.
[015] In yet another aspect, the kingpin arrangement is protected from contamination by means of a cassette seal and the kingpin cover integrated with sealing means (e.g. O-ring) results in a longer useful life of the kingpin arrangement. Castle nuts are used to pre-load the system more precisely according to the design requirement. Swiveling motion of axle arm with respect to kingpin achieved via the taper roller bearing and the angular contact toroidal bearing positioned in upper and lower arms of the axle arm.
BRIEF DESCRIPTION OF DRAWINGS:
[016] A preferred embodiment of the invention is described below with reference to the accompanying drawing, in which;

[017] Figure. 2 illustrates a cross sectional view of kingpin arrangement according to an
embodiment herein;
[018] Figure. 3 illustrates a cross sectional view of the axle arm of the system according to
an embodiment herein;
[019] Figure. 4 illustrates a cross sectional view of the axle beam of the system according to
an embodiment herein;
[020] Figure. 5 illustrates a kingpin component according to embodiment herein;
[021] Figure. 6 illustrates a cross sectional view of an axle arm sub-assembly according to
an embodiment herein;
[022] Figure. 7 illustrates a cross sectional view of a taper roller bearing according to an
embodiment herein;
[023] Figure. 8 illustrates a cross sectional view of an angular contact toroidal bearing
according to an embodiment herein;
[024] Figure. 9 illustrates a cross sectional view of a top cover according to an embodiment
herein;
[025] Figure. 10 illustrates a cross sectional view of a bottom cover according to an
embodiment to an embodiment herein;
[026] Figure. 11 illustrates a cross sectional view of a cassette seal according to an
embodiment to an embodiment herein;
[027] Figure. 12 illustrates a cross sectional view of a top castle nut according to an
embodiment to an embodiment herein;
[028] Figure. 13 illustrates a cross sectional view of a bottom castle nut according to an
embodiment to an embodiment herein; and

[029] Figure. 14 illustrates a cross-sectional view of kingpin arrangement of Figure.2 with a wheel arranged on the axle arm.
DETAILED DESCRIPTION OF THE INVENTION:
[030] Figure. 2 illustrates a cross sectional view of kingpin arrangement according to an embodiment herein. The kingpin arrangement comprises a kingpin component (2), an axle arm (3), an axle beam (1), a taper roller bearing (10), an angular contact toroidal bearing (16), a top cover (23) with sealing means (24) (e.g. O-ring), bottom cover (25) with sealing means (26) (e.g. O-ring), Cassette seal (30), a top castle nut (27) and a bottom castle nut (28). The axle beam (1) has a taper hole (lc) for securing the kingpin component (2). The kingpin component (2) has the middle portion (2c) which is in taper configuration by means of which kingpin (2) is rigidly secured in the axle beam (1). The kingpin component (2) has an upper portion (2a) and lower portion (2b) made up of cylindrical shape. The upper portion (2a) is in smaller in diameter compared to the lower portion (2b). The upper portion (2a) of the kingpin component (2) equipped with threaded end (2e), similarly lower portion (2b) of the kingpin component (2) also equipped with threaded end (2d). A top castle nut (27) is secured on threaded end (2e) and bottom castle nut (28) is secured on threaded end (2d) of kingpin component (2).
[031] In one embodiment, both taper roller bearing (10) and angular contact toroidal bearing (16) are packed with high quality lubrication and integrated with seals for high durability. This enhances the productivity of axle build due to elimination of greasing and

seal fitment operations during axle assembly build. Hence, this kingpin arrangement doesn't call for periodic maintenance. In another embodiment, the angular contact toroidal bearing (16) is particularly designed to take care of misalignment that exists in kingpin arrangement. This enhances the productivity of axle build due to elimination of greasing and seal fitment operations during axle assembly build.
[032] The kingpin arrangement provides low rotational resistance of axle arm (3) with respect to the kingpin component (2) due to usage of specially designed taper roller bearing (10) and angular contact toroidal bearing (16) to provide line contact of rollers between the inner and outer rings.
[033] The kingpin arrangement is designed such that the taper roller bearing (10) absorbs the axial forces due to motor vehicle front axle weight as a primary requirement and takes care of radial forces that arise during cornering maneuver of a motor vehicle as a secondary requirement. The angular contact toroidal bearing (16) takes care of only radial forces and takes care of entire kingpin arrangement misalignment.
[034] Figure. 3 illustrates a cross sectional view of the axle arm (3) of the system according to an embodiment herein. The axle beam (1) is provided with taper bore (lc) for accommodating the kingpin component (2). The axle arm (3) has cylindrical bores (5,7) in upper arm (4) as well as in lower arm (6) located at an axial distance from one another and are aligned axially. The top cylindrical bore (5) in the upper arm (4) of axle arm (3) is equipped with a bearing seat (5a) for receiving the taper roller bearing (10). The inner ring (13) of the taper roller bearing (10) that is secured around upper portion (2a) of kingpin

component (2) and the outer ring (14) is arranged in the bearing seat (5a) of axle arm (3). The bearing seat (5a) has a stop surface (5b) that defines the mounting position of outer ring (14). The integrated cassette seal (11) of taper roller bearing (10) interacts with the axle beam (1) that prevents dust penetrating into the taper roller bearing (10) via lower opening of through cylindrical bore (9). Bottom cylindrical bore (7) in the lower arm (6) of axle arm (3) is equipped with a bearing seat (7a) for receiving the angular contact toroidal bearing (16). Inner ring (17) of angular contact toroidal bearing (16) is secured around lower portion (2b) of kingpin component (2) and outer ring (18) is arranged in bearing seat (7a) of the axle arm (3). The bearing seat (7a) has a stop surface (7b) that defines the mounting position of the outer ring (18) of the angular contact toroidal bearing (16).
[035] The kingpin component (2) is pressed with press-force to have better integrity of the kingpin component (2) with axle beam (1) and the position of the kingpin component (2) is retained by a torqueing the top castle nut (27) to the design requirement. The top castle nut (27) is screwed onto the threaded portion of upper end (2e) of the kingpin component (2) until it comes in contact with the inner ring (13) upper surface of taper roller bearing (10). The top castle nut (27) is then tightened to a predetermined torque by means of special tool. Once top castle nut (27) has been torqued, the lower surface of top castle nut (27) loads the inner ring (13) of taper roller bearing (10) with a compressive force. This compressive force which acts to press the inner ring (13) downward, is transmitted to outer ring (14) of taper roller bearing (10) via rolling elements called rollers (15). The force is substantially transferred to axle arm (3) via bearing seat surface (5a). Thus the taper roller bearing (10) is designed to take up axial forces in relation to center axis (29) of kingpin component (2).

[036] Figure. 4 illustrates a cross sectional view of the axle beam (1) of the system according to an embodiment herein. Figure. 5 illustrates a kingpin component (2) according to embodiment herein.
[037] Figure. 6 illustrates a cross sectional view of an axle arm sub-assembly (22) according to an embodiment herein. The axle arm sub-assembly (22) is made with a taper roller bearing (10) which is pressed inside cylindrical bore (5) of the upper arm (4) of axle arm (3), an angular contact toroidal bearing (16) which is pressed inside the cylindrical bore (7) of lower arm (6) of axle arm (3) and the cassette seal (30) pressed inside the cylindrical bore (8) located at the top of lower arm (6). The cylindrical bore (7) capable of receiving the angular contact toroidal bearing (16) and the cylindrical bore (5) capable of receiving the taper roller bearing (10).
[038] The axle arm sub-assembly (22) is placed over axle beam (1) for kingpin assembly, bores of taper roller bearing inner ring (13) and angular contact toroidal bearing inner ring (17) are aligned with axle beam bore (lc) for smoother entry of kingpin component (2). After positioning the kingpin component (2), a pre-determined press load is applied on the bottom end (2d) of the kingpin component (2) for securing the kingpin component (2) with the axle beam (1). The kingpin component (2) position with respect to axle beam (1) is retained by top castle nut (27) which is placed over the inner ring (13) of taper roller bearing (10) at the top end (2e) of the kingpin component (2).

[039] Swiveling motion of axle arm (3) with respect to the kingpin component (2) attained via taper roller bearing (10) at upper portion (2a) and angular contact toroidal bearing (16) at lower portion (2b) of kingpin component (2). Bottom castle nut (28) mounted on inner ring (17) of the angular contact toroidal bearing (16) at bottom end (2d) of kingpin component (2) is used for pre-loading the entire kingpin arrangement. Rotational resistance, or so called drag-torque of axle arm (3) varies with extent of pre-load that can be achieved by torqueing the bottom castle nut (28). The bottom castle nut (28) allows pre-loading the kingpin arrangement to a pre-determined value with more precision.
[040] Figure. 7 illustrates a cross sectional view of a taper roller bearing (10) according to an embodiment herein. Figure. 8 illustrates a cross sectional view of an angular contact toroidal bearing (16) according to an embodiment herein. The axle arm (3) has an upper arm (4) and a lower arm (6) which are positioned axially at a distance to accommodate axle beam (1) width. The upper arm (4) has a through cylindrical bore (5) for physical interaction with outer ring (14) of the taper roller bearing (10). The lower arm (6) also has a cylindrical bore (7) for physical interaction with the outer ring (18) of the angular contact toroidal bearing (16). The inner ring (13) of the taper roller bearing (10) has a through bore (13a) for receiving kingpin (2) upper portion (2a), similarly the angular contact toroidal bearing (16) has a through bore (17a) for receiving the lower portion (2b) of the kingpin component (2). The axle arm sub assembly (22) is constructed with taper roller bearing (10) pressed inside the cylindrical bore (5) in the upper arm (4).
[041] The angular contact toroidal bearing (16) pressed inside the bottom cylindrical bore (7) and a cassette seal (30) pressed inside the cylindrical bore (8). The axle arm sub-assembly

(22) positioned onto the axle beam (1) such that the inner ring (13) of the taper roller bearing (10) and the inner ring (17) of the angular contact toroidal bearing (16) are aligned for fitment of the kingpin component (2).
[042] The angular contact toroidal bearing (16) is designed in such a way that it takes only radial loads and takes care of the kingpin component (2) misalignment exists due to component manufacturing tolerances. Uniqueness of using angular contact toroidal bearing (16) in kingpin arrangement is to have lower rotational resistance due line contact of rollers. Predetermined pre-loading can be given with very minimal axial displacement of toroidal bearing inner ring (17).
[043] Figure. 9 illustrates a cross sectional view of a top cover (23) according to an embodiment herein. Figure. 10 illustrates a cross sectional view of a bottom cover (25) according to an embodiment to an embodiment herein. The entire kingpin arrangement is effectively sealed to enhance the service life of components by using top cover (23) integrated with O-ring (24) to seal upper end (2e) of kingpin component (2), cassette seal (30) to seal the gap between bottom surface (lb) of the axle beam (1) and lower arm (6) top surface of axle arm (3), bottom cover (25) integrated with O-ring (26) to seal lower end (2d) of kingpin component (2) and the gap between the upper surface (la) of axle beam (1) and upper arm (4) bottom surface is sealed with cassette seal (11) integrated in the taper roller bearing (10). The top cover (23) is integrated with sealing means (24) (e.g. O-ring) screwed by means of threads (23a) that are arranged in the upper opening of through cylindrical bore (5).

[044] The top cover (23) sealing means (24) (e.g. O-ring) screwed by means of threads (23a) that are arranged in the upper opening of through cylindrical bore (5), creates a tight seal to prevent dust entry through that path which seals taper roller bearing (10), castle nut (27) and the upper end of the kingpin component (2). Bottom cover (25) is integrated with sealing means (26) (e.g. O-ring) screwed by means of threads (25a) that are arranged in the lower opening of through cylindrical bore (7). The sealing means (26), creates a tight seal for lower opening of through cylindrical bore (7), so that dust can't enter through that path which seals angular contact toroidal bearing (16), castle nut (28) and the lower end of the kingpin component (2) for improving the service life of components.
[045] Figure. 11 illustrates a cross sectional view of a cassette seal (30) according to an embodiment to an embodiment herein. The cassette seal (30) is arranged in upper opening of through cylindrical bore (8) of lower arm (6) of axle arm (3). The cassette seal (30) secured circumferentially in the second cylindrical bore (8) of lower arm (6) of the axle arm (3). Second cylindrical bore (8) equipped with seal resting face (8b) that defines the position of cassette seal (30). The cassette seal (30) has physical interaction with the axle beam bottom surface (lb) that prevents the entry of dust particles.
[046] Figure. 12 illustrates a cross sectional view of a top castle nut (27) according to an embodiment to an embodiment herein. Figure. 13 illustrates a cross sectional view of a bottom castle nut (28) according to an embodiment to an embodiment herein. The bottom castle nut (28) is used to pre-load the entire kingpin arrangement for desired rotational resistance of axle arm (3) with respect to kingpin axis (29).

[047] Figure. 14 illustrates a cross-sectional view of kingpin arrangement of Figure.2 with a wheel arranged on the axle arm (3). The axle arm (3) on which a wheel hub (31) supported via unitized bearing unit (32), and a disc brake rotor (33) is also mounted on the wheel hub (31).
[048] This invention no way limited to the embodiment described in the drawing sheet, but rather can be varied freely within the limits of the claims. Pre-loading to the kingpin arrangement can be done by means of special nuts.

LIST OF COMPONENTS WITH RESPECT TO REFERENCE NUMERALS:
a kingpin component (2)
an upper portion (2a),
a lower portion (2b)
a middle portion (2c)
an axle beam (1)
a taper bore (lc)
an axle arm sub-assembly (22)
a taper roller bearing (10)
an angular contact toroidal bearing (16)
bores (13a, 17a)
an axle arm (3)
an upper arm (4)
a lower arm (6)
a top castle nut (27)
a bottom castle nut (28)
an inner ring (13) of the taper roller bearing (10)
an inner ring (17) of the angular contact toroidal bearing (16)
an cassette seal (11)
a top cover (23)
a bottom cover (25)
cassette sealing means (30)
sealing means (24, 26)

We Claim:
1. A system for non-drive steerable axles of a vehicle, comprising:
a kingpin component (2) having an upper portion (2a), a lower portion (2b) and a middle portion (2c), wherein a configuration of said middle portion (2c) is in taper design;
an axle beam (1) having a taper bore (lc) for accommodating the kingpin component (2);
an axle arm sub-assembly (22) having a taper roller bearing (10) and an angular contact toroidal bearing (16), wherein bores (13a, 17a) of the taper roller bearing (10) and the angular contact toroidal bearing (16) are aligned with the taper bore (lc) to ensure ingress of the kingpin component (2) via the axle beam (1); and
an axle arm (3) is part of axle arm sub-assembly (22), said axle arm (3) comprises an upper arm (4) and a lower arm (6) for accommodating the axle beam (1), wherein said upper arm (4) swivels around the upper portion (2a) of the kingpin component (2) via said taper roller bearing (10), and said lower arm (6) swivels around the lower portion (2b) of the kingpin component (2) via said angular contact toroidal bearing (16) during an operation of the vehicle.
2. The system as claimed in claim 1, comprises
a top castle nut (27) is positioned over an inner ring (13) of the taper roller bearing (10) at top end (2e) of the kingpin component (2), wherein the position of the kingpin component (2) is retained by torqueing the top castle nut (27); and
a bottom castle nut (28) is positioned over an inner ring (17) of the angular contact toroidal bearing (16) at bottom end (2d) of the kingpin component (2) in order to preload the system for desired rotational resistance of the axle arm (3) with respect to center axis (29) of the kingpin component (2).

3. The system as claimed in claim 1, comprises
an cassette seal (11) is integrated with the taper roller bearing (10) to prevent dust penetrating into the taper roller bearing (10) via lower opening of a cylindrical bore (9).
4. The system as claimed in claim 1, comprises
a top cover (23) is integrated with sealing means (24) to seal the top castle nut (27), an upper end (2e) of the kingpin component (2), and the bore (5) of the axle arm (3);
a bottom cover (25) is integrated with sealing means (26) to seal the bottom castle nut (28), a lower end (2d) of the kingpin component (2), and the bore (7) of the axle arm (3); and
cassette sealing means (30) that seals the gap between a bottom surface (lb) of the axle beam (1) and the lower arm (6) of the axle arm (3).
5. The system as claimed in claim 1, wherein said angular contact toroidal bearing (16) is positioned in the axle arm sub-assembly (22) in predetermined mode, to absorb radial load in the kingpin component (2).
6. The system as claimed in claim 2, wherein the taper roller bearing (10) is configured to absorb axial load being occurred in relation to the center axis (29) of the kingpin component (2).
7. The system as claimed in claim 1, wherein said taper roller bearing (10) and said angular contact toroidal bearing (16) are filled with lubrication means for durability.
8. The system as claimed in claim 1, wherein said cassette seal (30) prevents dust penetrating in the gap exist between axle beam (1) bottom surface (lb) and lower arm top surface of axle arm (3).

9. A method of assembling a system for non-drive steerable axles of a vehicle,
comprising:
positioning an upper arm (4) and a bottom arm (6) of said axle arm (3) axially at a
predetermined distance to accommodate an axle beam (1);
inserting a kingpin component (2) via taper bore (lc) of the axle beam (1);
positioning a taper roller bearing (10) in the upper arm (4) of the axle arm (3) to enable the upper arm (4) swivels around an upper portion (2a) of the kingpin component (2); and
positioning an angular contact toroidal bearing (16) in the bottom arm (6) of the axle arm (3) to enable the lower arm (6) swivels around a lower portion (2b) of the kingpin component (2).
10. The method as claimed in claim 9, wherein said method comprises
positioning a top castle nut (27) over an inner ring (13) of the taper roller bearing
(10) at top end (2e) of the kingpin component (2) to retain position of the kingpin component (2); and
positioning a bottom castle nut (28) over an inner ring (17) of the angular contact toroidal bearing (16) at bottom end (2d) of the kingpin component (2) to preload the system for desired rotational resistance of the axle arm (3) with respect to center axis (29) of the kingpin component (2).
11. The method as claimed in claim 9, comprising the steps of:
integrating an cassette seal (11) with the taper roller bearing (10) to prevent dust penetrating into the taper roller bearing (10) via lower opening of a cylindrical bore (9);
integrating a top cover (23) with sealing means (24) to seal the top castle nut (27), an upper end (2e) of the kingpin component (2), and the bore (5) of the axle arm (3); and

integrating a bottom cover (25) with sealing means (26) to seal the bottom castle nut (28), a lower end (2d) of the kingpin component (2), and the bore (7) of the axle arm (3).