Claims:
1. An improved hub sub-assembly with hub play adjustment for axle beam comprising
at least one axle beam (1);
at least one axle spindle (2);
at least one axle shaft (16);
at least one hub sub-assembly (8) comprising a hub outboard bearing having a bearing cup (10) and bearing cone (11);
at least one circlip (9) configured to be mounted in the groove provided on said hub sub-assembly (8);
at least one hub inboard bearing cup (6) configured to be pressed in the hub to butt with the hub shoulder;
at least one inboard bearing inner cone (7) configured to be mounted on the bearing cup (6);
at least one spacer (5) and hub seal (4) configured to be pressed in the hub (8); and
at least one shim pack (12) provided between hub outboard bearing inner cone (11) and hub shim resting surface of axle spindle (2) configured to maintain optimal hub bearing pre-load and hub bearing play.

2. The improved hub sub-assembly with hub play adjustment for axle beam as claimed in claim 1, wherein said hub outboard bearing having a bearing cup (10) and bearing cone (11) is configured to be inserted in the hub (8).

3. The improved hub sub-assembly with hub play adjustment for axle beam as claimed in claim 1, wherein said hub sub-assembly (8) configured to be provided with at least one circlip (9) mounted in the groove provided on said hub sub-assembly (8), to lock the axial position of hub outboard bearing cup (10).

4. The improved hub sub-assembly with hub play adjustment for axle beam as claimed in claim 1, wherein said thickness of the shim (12) is configured by measuring a distance ‘E’, the nominal gap between spindle “shim resting face” (19) and hub outboard inner race face (20), the Gap distance ‘E’ is calculated by formula ‘E’ = Distance ‘D’ – Distance (A+B+C) wherein distance ‘A’ is thickness of pressure ring (3), distance ‘B’ is width of hub inboard inner race (7), distance ‘C’ is the distance between hub inboard (7) and outboard (11) inner races, distance ‘D’ is the distance between pressure ring resting surface (18) and shim resting face (19).

5. The improved hub sub-assembly with hub play adjustment for axle beam as claimed in claim 1, wherein said hub play of said shim pack (12) is configured by adding the Gap distance ‘E’ and additional shim equivalent to the required hub play value.

6. The improved hub sub-assembly with hub play adjustment for axle beam as claimed in claim 1, wherein said “bearing preload” of shim pack (12) is configured by subtracting shim equivalent to generate required hub bearing preload value from the Gap distance ‘E’.

7. The improved hub sub-assembly with hub play adjustment for axle beam as claimed in claim 1, wherein said shim pack (12) is configured to be inserted between uniquely designed spindle face (19) and hub outer bearing face (20) for restricting the inward movement of hub outboard bearing inner race (11).

8. The improved hub sub-assembly with hub play adjustment for axle beam as claimed in claim 1, wherein relative position of said outboard bearing inner race (11) with respect outer race (10) is configured to remain unchanged on overtightening of the lock nut (14).

9. A Method of inserting shim pack (12) in improved hub sub-assembly with hub play adjustment for axle beam comprising the steps of:
• inserting the selected shim pack on spindle till it buts against spindle face (19) which acts as a positive stopper;
• taking hub sub assembly and assembling it on spindle (2) till inner race (7) of inboard bearing rest to pressure ring (3);
• assembling the tongue spacer (13) which restricts the rotation of hub outboard bearing inner race (11) while tightening hub lock nut (14);
• tightening the inner hub lock nut (14) with desired torque;
• assembling the lock washer (15) to restrict the rotation of hub outer lock nut (14);
• tightening the hub outer lock nut (14) with desired torque;
• bending the lug of lock washer into the groove of outer lock nut;
• assembling other parts like axle shaft (16) & bolt (17) to complete the remaining assembly.
, Description:FORM 2

THE PATENTS ACT, 1970
(39 of 1970)
&
THE PATENT RULES, 2003

COMPLETE SPECIFICATION
(See Section 10 and Rule 13)

Title of invention:
AN IMPROVED SPINDLE AND SHIM ASSEMBLY FOR HUB PLAY OR PRELOAD ADJUESTMENT FOR AXLE

Applicant:
Tata Motors Limited
A company Incorporated in India under the Companies Act, 1956
Having address:
Bombay House, 24 Homi Mody Street,
Hutatma Chowk, Mumbai 400001,
Maharashtra, India

The following specification particularly describes the invention and the manner in which it is to be performed.
FIELD OF THE INVENTION

[001] The present invention generally related to the “Axle” of a vehicle, and more particularly the present invention is related to hub bearing play / preload adjustment, by elimination of the distance spacer and shims and with the help of uniquely designed spindle with shim arrangement.

BACKGROUND OF THE INVENTION

[002] In an axle, where conventional two taper roller bearing arrangement is used, to either preload the bearings or need to maintain desired “hub play” to achieve optimum bearing life.

[003] Bearing preload ensures constant contact between the ball complement and bearing races eliminating modes of play. This avoids axial movement between bearing cup (outer race) and complete cone assembly (inner race with rollers and cage). To achieve optimum bearing life, rollers are preloaded against bearing outer race by reducing the nominal distance between the bearing inner races of hub inboard & outboard bearings by torqueing the lock nut against outboard bearing inner race & maintained this position by using hub lock nut.

[004] Bearing play (Internal clearance) means the total distance through which one bearing ring can be moved relative to other in axial direction. Means, controlled axial movement is allowed between taper roller bearing inner & outer race. To achieve optimum bearing life, desired play in the bearings need to be maintained. The desired play in the hub inboard & outboard bearing is achieved by increasing the nominal distance between the bearing inner races of hub inboard and outboard bearings & maintained this position by using hub lock nut.

[005] In both the cases of optimizing bearing preload or bearing play, maintaining axial position of hub outboard bearing inner race with respect to outer race is very critical.

[006] Conventionally there are two methods to achieve the hub play. In first method, hub sub-assembly is mounted on the spindle & a locking nut is so tightened that the play between hub bearings becomes just zero & after that, unscrew the lock nut so as to get desired “hub play” in the system. In this method there are chances of excess bearing preload or excess play. The excessive bearing play will result in uneven tyre wear as well as reduced bearing life. On the other side, excessive preload due to overtightening of hub lock nut can result in to the seizure of the bearings, and hence hub unit and can lead to accident, which is more dangerous.

[007] So, the biggest disadvantage of this method - 1 is A) Hub play adjustment is operator dependent.
[008] B) Mechanism do not restrict overtightening of hub lock nut.

[009] In second arrangement, to eliminate the disadvantages elaborated in the method -1, a fix distance spacer & shims are used in between inner & outer hub bearing inner races to maintain desired hub play.

[0010] In this arrangement distance between inner races of hub inner and outer bearing is measured, and accordingly a fix distance spacer and combinations of shims are assembled between the hub inner and outer bearing inner races, so as to get the desired hub play. In this arrangement gap between inner races of hub inboard and hub out board bearing is filled with fix spacer & shims, hence even with overtightened lock nut, preloading is avoided. This spacer adds to the cost of assembly.

[0011] Accordingly, there is a need of cost effective hub play or preload adjustment mechanism, which will achieve desired hub play or preload without fix distance spacer & still make it insensitive to overtighten hub lock nut.

OBJECTS OF THE INVENTION

[0012] One object of the present disclosure is to provide hub play adjustment mechanism for an axle that is simple in construction.

[0013] Another object of the present disclosure is to provide hub play adjustment mechanism for an axle that is easy to set.

[0014] Yet another object of present disclosure is to provide hub play adjustment mechanism for an axle that has less no of parts.

[0015] Also, yet another object of the present disclosure is to maintain and protect all benefits of current hub play mechanism for an axle with lesser number of parts.

SUMMARY OF THE INVENTION

[0016] The present subject matter discloses an improved hub sub- assembly with hub play adjustment for axle beam comprising an axle beam, an axle spindle , an axle shaft, a hub sub-assembly comprising a hub outboard bearing having a bearing cup and bearing cone; at least one circlip configured to be mounted in the groove provided on said hub sub-assembly. A hub inboard bearing cup configured to be pressed in the hub to butt with the hub shoulder and an inboard bearing inner cone configured to be mounted on the bearing cup. A spacer and hub seal configured to be pressed in the hub and a shim pack provided between hub outboard bearing inner race face and hub shim resting surface of axle spindle configured to maintain optimal hub bearing pre-load or hub bearing play.

[0017] The hub outboard bearing having a bearing cup and bearing cone is configured to be inserted in the hub. The hub sub-assembly configured to be provided with at least one circlip mounted in the groove provided on said hub sub-assembly, to lock the axial position of hub outboard bearing cone. The thickness of the shim is calculated by measuring a distance ‘E’, the nominal gap between spindle “shim resting face” and hub outboard inner race face , the Gap distance ‘E’ is calculated by formula ‘E’ = Distance ‘D’ – Distance (A+B+C) wherein distance ‘A’ is thickness of pressure ring , distance ‘B’ is width of hub inboard inner race , distance ‘C’ is the distance between hub inboard and outboard inner races, distance ‘D’ is the distance between pressure ring resting surface and shim resting face .

[0018] The hub play of said shim pack is configured by adding the Gap distance ‘E’ and additional shim equivalent to the required hub play value. The “bearing preload” of shim pack is configured by subtracting shim equivalent to the required hub bearing preload value from the Gap distance ‘E’. The shim pack is configured to be inserted between uniquely designed spindle face and hub outer bearing inner race face for restricting the inward movement of hub outboard bearing inner race. The relative position of said outboard bearing inner race with respect outer race is configured to remain unchanged on overtightening of the lock nut.

[0019] A Method of inserting shim pack in improved hub sub-assembly with hub play adjustment for axle beam comprising the steps of:
• inserting the selected shim pack on spindle till it buts against spindle face which acts as a positive stopper;
• taking hub sub assembly and assembling it on spindle till inner race of inboard bearing rest to pressure ring;
• assembling the tongue spacer which restricts the rotation of hub outboard bearing inner race while tightening hub lock nut;
• tightening the inner hub lock nut with desired torque;
• assembling the lock washer to restrict the rotation of hub outer lock nut;
• tightening the hub outer lock nut with desired torque;
• bending the lug of lock washer into the groove of outer lock nut;
assembling other parts like axle shaft & bolt to complete the remaining assembly.

BRIEF DESCRIPTION OF THE ACCOMPANYING FIGURES
[0020] The foregoing detailed description of embodiments is better understood when read in conjunction with the appended drawings. For the purpose of illustrating the present subject matter, an example of construction of the present subject matter is provided as figures.
[0021] The present subject matter is described in detail with reference to the accompanying figures. In the figures, the left-most digit(s) of a reference number identifies the figure in which the reference number first appears. The same numbers are used throughout the drawings to refer various features of the present subject matter. One or more embodiments are now described, by way of example only, with reference to the accompanying figures wherein like reference numerals present like elements and in which:
[0022] Figure 1 illustrates a sectioned view of hub sub-assembly.

[0023] Figure 2 illustrates a sectioned view of conventional corner module with two taper roller bearing arrangement with a hub play construction, in accordance with embodiment of the present invention.

[0024] Figure 3 illustrates a sectioned view of conventional corner module with two taper roller bearings arrangement with a hub play construction, in accordance with embodiment of the present invention.

[0025] Figure 4 illustrates a sectional view to understand the process for calculating hub shim pack with a unique hub paly construction, in accordance with embodiment of the present invention.

[0026] The figures depict embodiments of the disclosure for the purpose of illustration only. One skilled in the art readily recognize from the following description that alternative embodiments of the system illustrated herein may be employed without departing from the principles of the disclosure described herein.

[0027] REFERRAL NUMERALS:

Element Description Reference Numeral
Axle Beam 1
Axle Spindle 2
Pressure Ring 3
Hub Seal 4
Spacer 5
Inboard Bearing Inner Cup 6
Inboard Bearing Inner Cone 7
Hub 8
Circlip 9
Hub Outboard Bearing Cup 10
Hub Outboard Bearing Cone 11
Shim Pack 12
Tongue Spacer 13
Hub Lock Nut 14
Lock Washer 15
Axle Shaft 16
Bolt 17
Pressure Ring Resting Surface 18
Shim Resting Face 19
Hub Outboard Inner Race Face 20
Inboard bearing cone face 21

DETAILED DESCRIPTION

[0028] Some embodiments of this disclosure, illustrating all its features, will now be discussed in detail. The words "comprising", “having”, and "including," and other forms thereof, are intended to be equivalent in meaning and be open ended in that an item or items following any one of these words is not meant to be an exhaustive listing of such item or items, or meant to be limited to only the listed item or items. It must also be noted that as used herein and in the appended claims, the singular forms "a," "an," and "the" include plural references unless the context clearly dictates otherwise. Although any devices and methods similar or equivalent to those described herein can be used in the practice or testing of embodiments of the present disclosure, the exemplary devices and methods are now described. The disclosed embodiments are merely exemplary of the disclosure, which may be embodied in various forms.

[0029] Various modifications to the embodiment will be readily apparent to those skilled in the art and the generic principles herein may be applied to other embodiments. However, one of ordinary skill in the art will readily recognize that the present disclosure is not intended to be limited to the embodiments illustrated but is to be accorded the widest scope consistent with the principles and features described herein.

[0030] The hub sub-assembly (Ref to Fig.1) according to the present disclosure comprises of a hub outboard bearing having a bearing Cup (10) & bearing cone (11), is inserted in to hub & circlip (9) is fixed in the groove, to lock the axial position of hub outboard bearing cup (10). Hub inboard bearing cup (6) is pressed in the hub till it butts the hub shoulder. Inboard bearing inner cone (7) is mounted on the bearing cup (6). Spacer (5) and hub seal (4) is pressed in the hub (8).

[0031] Once this sub assembly is ready to assemble on spindle (2) it is necessary to decide “Shim pack” (12) to maintain either “hub play” or “Hub bearing preload”.
[0032] To decide shim pack refer to the Fig.4. Measure distance ‘A’ of pressure ring (3), distance ‘B’ of hub inboard inner race width (7) & distance ‘C’ between hub inboard (7) & outboard (11) inner races. Measure distance ‘D’ on spindle (2).

[0033] To calculate gap ‘E’

Gap distance ‘E’ = Distance (A+B+C) - Distance ‘D’

Distance ‘E’ represents the nominal gap between spindle “shim resting face” (19) & hub outboard inner race face (20). To achieve desired “Hub play” shim pack or “bearing preload” shim pack following steps to be done.

1) Hub play shim pack = Shims equivalent to distance ‘E’ + Additional shim, equivalent to the required hub play value.
2) Hub preload shim pack = Shims equivalent to distance ‘E’ - shim, equivalent to generate required hub bearing preload value.

[0034] Once “Shim pack” is finalized with above method, insert the shim pack on spindle till it buts against spindle face (19) which acts as a positive stopper. Take hub sub assembly as per fig.1 & assemble it on spindle (2) till inner race (7) of inboard bearing rest to pressure ring (3). Assemble the tongue spacer (13) which restricts the rotation of hub outboard bearing inner race (11) while tightening hub lock nut (14). Tight the inner hub lock nut (14) with desired torque. As shim pack is inserted between uniquely designed spindle face (19), & hub outer bearing face (20), inward movement of hub outboard bearing inner race (11) is restricted. In case of overtightening of the lock nut (14) also, relative position of outboard bearing inner race (11) with respect outer race (10) remains unchanged. Assemble the lock washer (15) which restricts the rotation of hub outer lock nut (14). Tight the hub outer lock nut (14) with desired torque. Bend the lug of lock washer into the groove of outer lock nut. Assemble other parts like axle shaft (16) & bolt (17) to complete the remaining assembly.

[0035] The proposed arrangement to maintain hub bearing play or preload is an innovative design & contains less number of parts. This arrangement is having provision to restrict overtightening due to uniquely designed positive stopper on spindle & shim arrangement. Due to this proposed system, play or preload adjustment is achieved positively, irrespective of skilled manpower. This mechanism is robust enough to maintain play or preload in the system for long term. Cost reduction is achieved by means of deleting a conventional distance spacer between hub inboard & outboard bearing. With the proposed arrangement desired hub play / preload can be achieved in line with current conventional arrangement.

[0036] Advantages:

? Mechanism is simple in construction

? Very easy to set hub play or preload in the system.

? Less no of parts over current conventional set up.

? Proposed mechanism maintains & protect all benefits of current hub play mechanism for an axle with less no of parts.

? Pokayoke is provided in the system to restrict the overtightening of the locking nut.

? No skilled manpower is required to set the hub play or preload.

[0037] The present subject matter discloses an improved hub sub- assembly with hub play adjustment for axle beam comprising an axle beam (1), an axle spindle (2), an axle shaft (16), a hub sub-assembly (8) comprising a hub outboard bearing having a bearing cup (10) and bearing cone (11); at least one circlip (9) configured to be mounted in the groove provided on said hub sub-assembly (8). A hub inboard bearing cup (6) configured to be pressed in the hub to butt with the hub shoulder and an inboard bearing inner cone (7) configured to be mounted on the bearing cup (6), A spacer (5) and hub seal (4) configured to be pressed in the hub (8) and a shim pack (12) provided between hub outboard bearing inner cone (11) and hub shim resting surface of axle spindle (2) configured to maintain optimal hub bearing pre-load and hub bearing play.

[0038] The hub outboard bearing having a bearing cup (10) and bearing cone (11) is configured to be inserted in the hub (8). The hub sub-assembly (8) configured to be provided with at least one circlip (9) mounted in the groove provided on said hub sub-assembly (8), to lock the axial position of hub outboard bearing cup (10). The thickness of the shim (12) is calculated by measuring a distance ‘E’, the nominal gap between spindle “shim resting face” (19) and hub outboard inner race face (20), the Gap distance ‘E’ is calculated by formula ‘E’ = Distance ‘D’ – Distance (A+B+C) wherein distance ‘A’ is thickness of pressure ring (3), distance ‘B’ is width of hub inboard inner race (7), distance ‘C’ is the distance between hub inboard (7) and outboard (11) inner races, distance ‘D’ is the distance between pressure ring resting surface (18) and shim resting face (19).

[0039] The hub play of said shim pack (12) is configured by adding the Gap distance ‘E’ and additional shim equivalent to the required hub play value. The “bearing preload” of shim pack (12) is configured by subtracting shim equivalent to generate required hub bearing preload value from the Gap distance ‘E’. The shim pack (12) is configured to be inserted between uniquely designed spindle face (19) and hub outer bearing face (20) for restricting the inward movement of hub outboard bearing inner race (11). The relative position of said outboard bearing inner race (11) with respect outer race (10) is configured to remain unchanged on overtightening of the lock nut (14).

[0040] A Method of inserting shim pack (12) in improved hub sub-assembly with hub play adjustment for axle beam comprising the steps of:
• inserting the selected shim pack on spindle till it buts against spindle face (19) which acts as a positive stopper;
• taking hub sub assembly and assembling it on spindle (2) till inner race (7) of inboard bearing rest to pressure ring (3);
• assembling the tongue spacer (13) which restricts the rotation of hub outboard bearing inner race (11) while tightening hub lock nut (14);
• tightening the inner hub lock nut (14) with desired torque;
• assembling the lock washer (15) to restrict the rotation of hub outer lock nut (14);
• tightening the hub outer lock nut (14) with desired torque;
• bending the lug of lock washer into the groove of outer lock nut;
assembling other parts like axle shaft (16) & bolt (17) to complete the remaining assembly.