AXEL ASSEMBLY

Abstract

An axle assembly having a wheel flange with a central opening and a slot having an end dimensioned to fit within the wheel flange central opening. A molten binder, such as molten zinc, fills the space in between the wheel central opening and the shaft end. Upon cooling, the binder locks the wheel flange and shaft together.

Description

BACKGROUND OF THE INVENTION

I. Field of the Invention

The present invention relates to an axle assembly for small motors including a method for constructing the same.

II. Description of Related Art

There are many products, such as snowmobiles, golf carts, chainsaws, small motorized vehicles, and the like, which utilize small internal combustion engines to power them. In these products, the overall cost of construction is an important, if not the most important, criteria for the engine.

Many of these devices that are powered by an internal combustion engine include an axle assembly and transmission having a shaft with a wheel flange formed at one end of the shaft. Previously, many of these axle assemblies have been of a one piece construction in which the axle assembly is first formed by casting a metal part in the general form of the axle assembly and thereafter machining the molded part to its final form. Such machining, furthermore, often requires a plurality of different machining operations.

The necessity to perform multiple machining operations, as well as the initial forging operation, in order to completely machine the axle assembly is not only time consuming, but expensive. Indeed, the expense of the axle assembly significantly increases the overall cost of the engine.

SUMMARY OF THE PRESENT INVENTION

The present invention provides an axle assembly which overcomes the above-mentioned disadvantages of the previously known axle assemblies.

In brief, the axle assembly of the present invention comprises a wheel flange having a central opening. Preferably, the wheel flange is formed from powdered metal which requires little or no further machining after the wheel flange is molded from the powdered metal. The wheel flange may be formed from any conventional powdered metal material and includes a central opening.

An elongated shaft then has an end connection to fit within the wheel flange central opening. The shaft itself is machined from metal, such as steel, in the conventional fashion. Furthermore, one end of the shaft includes a plurality of external splines.

The splined end of the shaft is dimensioned to fit within the central opening of the wheel flange. When the wheel flange and shaft are aligned as desired relative to each other, a binder, such as liquid zinc, is then injected in between the wheel flange and the shaft so that, upon cooling, the binder locks the wheel flange and shaft together. Additional through openings through the wheel flange are preferably formed which also receive the binder. Consequently, once the binder has cooled and solidified, the wheel flange and shaft are rigidly held together.

BRIEF DESCRIPTION OF THE DRAWING

A better understanding of the present invention will be had upon reference to the following detailed description when read in conjunction with the accompanying drawing, wherein like reference characters refer to like parts throughout the several views, and in which:

FIG. 1 is an elevational view illustrating a preferred embodiment of the present invention;

FIG. 2 is a fragmentary exploded view illustrating the assembly of the axle assembly;

FIG. 3 is an exploded fragmentary side view;

FIG. 4 is a fragmentary longitudinal sectional view of the axle assembly prior to injection of the molten zinc;

FIG. 5 is a view similar to FIG. 3 but after the zinc injection; and

FIG. 6 is an end sectional view.

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT OF THE PRESENT INVENTION

With reference first to FIGS. 1 and 2, a preferred embodiment of the axle assembly 10 of the present invention is shown. The axle assembly 10 includes an elongated shaft 12 having a wheel flange 14 attached at one end 16 of the shaft 12 in a fashion that will be subsequently described in greater detail.

The wheel flange 14 is preferably constructed from powdered metal which is molded into its desired shape by a mold (not shown) and then sintered. Consequently, the overall shape of the wheel flange 14 is generally flat and planar. Furthermore, little, if any, machining is required after the wheel flange 14 is molded into its desired shape and sintered which results in a low-cost construction.

Referring now particularly to FIGS. 1 and 3, the wheel shaft 12 is constructed in a conventional fashion from a hard material, such as a steel alloy. The shaft is machined into its form and, once the machining is completed, heat treated for increased strength of the shaft 12. Any conventional means, such as induction heating, may be used to strengthen the shaft 12 and a final grinding operation may be performed following the heat treatment of the shaft 12.

As best shown in FIGS. 2 and 3, the wheel flange 14 includes a central throughbore 20 having a diameter greater than the diameter of the end 16 of the shaft 12. This end 16 of the shaft 12 is then positioned centrally within the through bore 20 as shown in FIG. 4. Furthermore, the end 16 of the shaft 12 is machined into a noncircular shape, such as by knurling 22.

As best shown in FIGS. 2 and 6, the opening 20 in the flange 14 is noncircular in shape and includes a plurality of cutouts or scallops 24 around the opening 20. Furthermore, at least one, and preferably a plurality of through bores 26 are formed through the wheel flange 14 when the wheel flange 14 is initially formed. These through bores 26 are preferably circumferentially equidistantly spaced around the central opening 20.

After the wheel flange 14 has been fully molded and the shaft 12 machined as previously described, the knurled end 16 of the shaft is positioned centrally within the wheel flange 20 as shown in FIG. 4. Appropriate jigs (not shown) are employed to align the wheel flange 14 and shaft together so that the wheel shaft 12 is perpendicular to the wheel flange 14. The aligned shaft 12 and flange 14 are positioned within a mold 29 which forms a molding chamber 31 around the end of the shaft 12 and a central portion of the wheel flange 14.

Molten zinc is cast into the chamber 31 around the end 16 of the shaft so that the liquid zinc 30 fills not only the space between the end 16 of the shaft 12 and the wheel flange 14, but also extends through and completely fills the holes 26 formed through the wheel flange 14. This liquid zinc also fills within the uneven nor noncircular outer surface of the shaft 12 as well as within the noncircular recesses in the flange 14.

As the zinc 30 cools, the zinc 30 sets and becomes rigid. Upon doing so, the zinc 30 fills not only the noncircular opening 20 and cutouts 24 in the wheel flange 14, but also the noncircular outer surface of the shaft 12 formed by the knurling 22. Consequently, once the molten zinc 30 is set, the zinc 30 rigidly secures the shaft 12 and wheel flange 14 together and with the wheel flange 14 perpendicularly aligned relative to the shaft 12.

From the foregoing, it can be seen that the present invention provides a simple and inexpensive axle assembly which can be accurately and repeatedly manufactured to high precision at relatively low cost. Having described my invention, however, many modifications thereto will become apparent to those skilled in the art to which it pertains without deviation from the spirit of the invention as defined by the scope of the appended claims.

Claims

1. A method for constructing an axle assembly comprising the steps of: forming a wheel flange with a central opening,machining an elongated shaft so that one end of the shaft has a smaller cross sectional shape than said central opening of said wheel flange,positioning said one end of said shaft into said wheel flange central opening,filing a space between said one end of said shaft and said wheel flange with a molten binder which, upon setting, mechanically locks said shaft and said wheel flange together.

2. The method as defined in claim 1 wherein said forming step comprises the step of forming said wheel flange from powdered metal.

3. The method as defined in claim 1 wherein said machining step comprises the step of forming knurls on said one end of said shaft.

4. The method as defined in claim 1 further comprising the step of heat treating said wheel flange.

5. The method as defined in claim 1 further comprising the step of heat treating said elongated shaft.

6. The method as defined in claim 5 further comprising the step of grinding said elongated shaft following the step of heat treating.

7. The method as defined in claim 1 wherein said molten binder comprises molten metal having zinc as one component.

8. The method as defined in claim 1 wherein said wheel flange has at least one through hole spaced radially outwardly from said wheel flange central opening and wherein said filling step comprises the step of filling said at least one through hole.

9. The method as defined in claim 3 wherein said filling step comprises the step of filling said knurls.

10. The method as defined in claim 1 wherein said wheel flange has a plurality of cutouts formed around said central opening and wherein said filling step comprises the step of filling said plurality of cutouts.

11. A method for constructing an axle assembly comprising the steps of: forming a wheel flange with a central opening, said wheel flange including a plurality of circumferentially spaced cutouts,machining an elongated shaft so that one end of the shaft has a smaller cross sectional shape than said central opening of said wheel flange,positioning said one end of said shaft into said wheel flange central opening,filing a space between said one end of said shaft and said wheel flange with a molten binder which, upon setting, mechanically locks said shaft and said wheel flange together.

12. The method as defined in claim 11 wherein said filling step comprises the step of filling said plurality of cutouts.

13. A method for constructing an axle assembly comprising the steps of: forming a wheel flange with a central opening, said wheel flange including a plurality of circumferentially spaced cutouts,machining an elongated shaft so that one end of the shaft has a smaller cross sectional shape than said central opening of said wheel flange, said elongated shaft including knurls formed on said one end of the elongated shaft,positioning said one end of said shaft into said wheel flange central opening,filing a space between said one end of said shaft and said wheel flange with a molten binder which, upon setting, mechanically locks said shaft and said wheel flange together.

14. The method as defined in claim 13 wherein said filling step comprises the step of filling said knurls.

15. The method as defined in claim 13 wherein said filling step comprises the step of filling said plurality of cutouts.