Two-piece hub extension

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a hub extension for attaching a dual wheels to a tractor front axle with mechanical front-wheel drive and in particular to a twopiece hub extension.

2. Description of the Related Art

Non-articulated, four-wheel drive agricultural tractors with a mechanical front-wheel drive (MFWD), where a steering axle is provided with drive capability, have become common place. Recently, dual front wheels have been added to the front axle the by attaching a hub extension to each axle hub and mounting a second wheel on each side of the tractor. The advantages of dual front wheels are improved traction and reduced soil compaction by decreasing the weight carried by each tire. A typical hub extension is a single piece structure or weldment that is generally barrel shaped, having a sleeve like body portion with an in-turned radial flanges at each end. One flange is bolted to the inner wheel and the axle hub so that the extension projects horizontally outward. The dual wheel is bolted to the outer flange of the hub extension. Since the radial flanges of the extension are in-turned, it is necessary to provide access openings in the extension body to reach bolts and nuts inside the extension. Installation and removal of the dual wheels and re-torquing of the bolts are difficult and cumbersome due to poor access to the nuts and bolts.

SUMMARY OF THE INVENTION

The hub extension of the present invention is of a two-piece construction having an inner extension ring that surrounds the final drive cover of the front axle and an outer extension member. The inner extension ring has inner and outer flanges like the above mentioned single piece hub extensions but only extends outward enough to clear the final drive cover of the axle. The inner ring is mounted by bolts that extend through both the outer and inner flanges and into the axle hub. As a result, the bolt heads are external of the inner ring and can be easily reached. The inner extension ring has cutout portions to provide clearance for a pair of diametrically spaced wheel mounting bolts that are used to first attach a wheel disc to the axle hub. This enables the inner wheel to be mounted to the axle hub first, before the extension is mounted.

The outer extension member has an axially inner mounting flange and an axially outer wheel flange. These flanges both project radially outward from the tubular body of the outer extension member. The mounting flange is scalloped to provide clearance for the bolts that mount the inner extension ring to the axle hub. Long bolts extend through the mounting flange of the outer extension member, through the inner extension ring and into the hub to attach the outer extension member to the axle hub. The dual wheel is mounted to the outer wheel hub.

It is an advantage of the two piece construction that all bolts are accessible without reaching into the interior of any of the extension components. Furthermore, the smaller diameter body of the outer extension member provides a greater clearance for crops between the inner and outer tires. In addition, the overall diameter of both the inner extension ring and the outer extension member is small enough to allow full use of multi-position wheels on the front drive axle.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1

is an exploded perspective view of a dual front wheel assembly containing the two hub extension of the present invention.

FIG. 2

a sectional view of the dual front wheel assembly shown in FIG.

1

.

FIG. 3

is an enlarged sectional view of the area contained in circle

3

in FIG.

2

.

FIG. 4

is an enlarged sectional view of the area contained in circle

4

in FIG.

2

.

FIG. 5

is a perspective view of a portion of the dual front wheel assembly shown in FIG.

1

.

DESCRIPTION OF THE PREFERRED EMBODIMENT

With reference to

FIG. 1

a dual front wheel assembly having the hub extension of the present invention as shown in FIG.

1

and designated generally at

10

. The dual front wheel assembly

10

includes the hub extension assembly

12

of the present invention which comprises an inner extension ring

14

and an outer extension member

16

, described more fully below.

The dual wheel assembly is mounted to an axle hub

20

that is part of the mechanical front-wheel drive axle of an agricultural tractor. The hub

20

includes a radial wheel flange

22

that has a circular pattern of threaded bolt apertures

24

. The tractor axle includes a planetary final drive (not shown) in a known manner. A final drive cover

26

conceals the final drive. The cover

26

extends axially outward beyond the wheel flange

22

. A radial flange

28

extends outward from the cover

26

and has apertures

30

aligned with the apertures

24

in the wheel flange. The wheel flange

22

extends radially outward beyond the final drive cover

26

. The final drive cover is coupled to the hub

20

by fasteners, not shown, in a known manner.

A pair of diametrically spaced wheel bolts

36

secures an inner wheel disc

34

to the wheel flange

22

. The bolts

36

are threaded into two of the bolt apertures

24

to secure the wheel disc

34

thereto. A wheel rim

38

is bolted to the periphery of the wheel disc

34

by bolts

39

(

FIG. 5

) using one of the two sets of apertures

40

and

42

on the rim

38

. The wheel disc

34

, rim

38

and tire

41

(

FIG. 5

) comprise a drive wheel assembly

44

. The drive wheel assembly

44

is a multi-position assembly that enables the tread width of the front tires to be varied by changing the orientation of the rim

38

relative to the disc

34

and/or changing the orientation of the wheel disc

34

relative to the hub

20

. A wide variety of tread width combinations can be produced.

The hub extension assembly

12

of the present invention is mounted to the hub

20

, outboard of the wheel disc

34

, to enable an outer, or dual, wheel and tire assembly

46

to be mounted to the axle and spaced outward of the inner wheel and tire assembly

44

to provide clearance for a crop row between the two tires. After the wheel disc

34

is mounted to the hub

20

, the inner extension ring

14

of the hub extension assembly is mounted to the hub

20

. The inner extension ring

14

is generally barrel shaped, having an axial sleeve

48

forming a main body and having an inner radial flange

50

and an outer radial flange

52

as seen in

FIGS. 2 and 3

. The inner and outer flanges

50

,

52

extend radially inward from the sleeve

48

. The inner and outer flanges are provided with bores

54

(

FIG. 1

) arranged in the same circular pattern as the apertures

24

of the wheel flange

22

.

The inner extension ring

14

is provided with cut out portions

56

(

FIGS. 1 and 5

) to provide clearance for the wheel bolts

36

that attach the wheel disc

34

to the hub

20

. Accordingly, the inner and outer flanges are divided into two arcuate segments

58

,

60

each having five bores

54

. Four ring-mounting bolts

62

initially mount the inner extension ring

14

with two bolts in each of the two arcuate segments

58

,

60

. The bolts are placed in the second and fourth bores in each segment. The ring mounting bolts

62

pass through both the inner and outer flanges of the inner extension ring, through the apertures in the wheel disc

34

and into the threaded apertures

24

in the wheel flange of the hub

20

. The ring mounting bolts thus also secure the wheel disc to the hub.

To properly position the inner extension ring on the hub, the final drive cover

26

is provided with a machined pilot surface

66

. A radially inner edge surface

68

of the inner flange

50

pilots on the surface

66

of the final drive cover. This properly centers the inner extension ring

14

on the final drive cover and hub

20

.

The outer extension member

16

has an axially extending sleeve

74

and axially spaces apart inner mounting flange

72

and outer wheel flange

76

at the ends of the axial sleeve

74

. The mounting flange

72

has a plurality of bolt apertures

78

arranged in a circular pattern having the same diameter as, and aligned with the apertures

24

in the wheel flange

22

. The mounting flange

72

is scalloped to provide clearance for the ring mounting bolts

62

. The mounting flange

72

only has half the number of apertures

78

as there are apertures

24

in the wheel flange

22

. The mounting flange

72

abuts the outer flange

52

of the inner extension ring (FIGS.

2

and

3

). Long bolts

80

extend through the mounting flange

72

, through both flanges of the inner extension ring, through the wheel disc

34

and into the threaded apertures

24

in the wheel flange

22

to mount the outer extension member to the hub. The long bolts

80

are placed in the first, third and fifth bores in each of the arcuate segments

58

,

60

of the inner extension ring.

The outer flange

52

of the inner extension ring is provided with an axially outwardly projecting lip

96

at the radial inner edge of the outer flange

52

. The lip

96

seats within an axially inwardly projecting lip

98

in the mounting flange

72

of the outer extension member

16

. The two lips form pilot surfaces to center the outer extension member

16

relative to the inner extension ring

14

.

The outer wheel flange

76

is provided with a circular pattern of threaded bolt apertures

82

. These apertures receive wheel bolts

84

to mount an outer wheel disc

86

to the outer extension member

16

. An outer wheel rim

88

is mounted to the disc

86

by bolts

90

and carries a tire

92

, forming the outer wheel and tire assembly

46

. In the embodiment shown, the outer wheel flange

76

has a smaller diameter bolt circle than the hub

20

. It will be readily appreciated that the diameter of the bolt pattern of the outer wheel hub could be the same as that of the pattern of the bolt apertures

24

if desired.

The outer wheel flange

76

is formed with an axially projecting lip

100

(

FIGS. 2 and 4

) at the radial inner edge of the flange

76

. This forms a pilot surface for the outer wheel disc

86

to insure proper positioning of the outer wheel and tire assembly

46

. The pilot surfaces cooperate to ensure the proper positioning of the inner and dual tires on the centerline of the axle hubs.

The larger diameter of the inner extension ring

14

provides clearance around the final drive cover

26

. The outer flange

52

is located axially just beyond the cover

26

so that the larger diameter ring

14

is not any longer axially than necessary. The smaller diameter of the axial sleeve

74

of the outer extension member provides greater crop clearance between the two tires. The inner extension ring and outer extension member are configured so that they do not interfere with the wheel discs

34

and

86

, enabling the discs to be used in any orientation to preserve the multipleposition feature of the wheel discs. All of the bolts can be accessed without reaching inside any of the components, providing easier mounting and removal of the dual wheel and tire assembly and re-torquing of the bolts. Removal of the outer extension member can be accomplished by removing fewer bolts as compared to prior designs and removal of the outer extension member does not disturb the mounting of the inner wheel and tire assembly

44

.

The invention should not be limited to the above-described embodiment, but should be limited solely by the claims that follow.