CA1246841A

CA1246841A - Wheel disc-to-rim assembly

Info

Publication number: CA1246841A
Application number: CA000475150A
Authority: CA
Inventors: Joseph F. Wagner
Original assignee: Deere and Co
Current assignee: Deere and Co
Priority date: 1984-03-22
Filing date: 1985-02-26
Publication date: 1988-12-20

Abstract

WHEEL DISC-TO-RIM ASSEMBLY
Abstract of the Disclosure A wheel is constructed in part by pressing a hot-formed disc into an extreme interference press-fit with a drop-center wheel rim without there being any surface preparation done to the outside diameter of the disc or to the inside diameter of the rim.

Description

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Background of the Invention The present invention relates to wheels for industrial vehicles and more particularly relates to such wheels as are of a construction having discs pressed into drop-center r-ims.
I t is known to construct wheels for industrial vehicles by pressing discs into drop-center rims and to dimension the outside diameter of an annular flange of the disc relative to the inside diameter of a cylindrical center section of the rim 1~ such that there is a high interference fit between the disc and rim. This f it is necessary to round out the wheel rim which may sometimes be oval shaped before the disc is pressed thereinto.
Heretofore, it has been the practice to form the disc by subjecting a plate to a hot-rolling operation so as to produce a i~ dish-shaped disc having an axially extending annular flange.
The outside diameter of the flange was then machined to produce a relatively smooth surface which was thought to enhance the movement of the disc into the rim during the pressing operation.
However, this known practice is not entirely satisfactory since during the pressing operation~ the surface of the rim traversed by the disc and the outside diameter surface of the disc flange both incur damage in the form of gouges or score marks with pieces of material actually being torn from the engaged surfaces of the disc and rim.
Summarv of the Invention The present invention relates to the making of industrial vehicle wheels and more specifically relates to the operation of forming wheels by pressing wheel discs into wheel rims.
An object of the invention is to take a wheel disc having an axial, annular flange dimensioned relative to an inside diameter of a wheel rim so as to produce an extreme interference fit when the parts are pressed together and to press the parts together without causing damage to either one.
Another object of the invention is to press a wheel disc into a wheel rim, as set forth in the previous object, by using a minimum amount of pressing force~
A more specific object of the invention is to press a hot-formed wheel disc, h2ving an outside diameter surface which is 40 in an as-formed condition into a wheel rim. ~-~

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1 These and other objects, features and advantages of the present invention will become apparent to those skilled in the art from the description which follows and from the drawings.
Brief Description of the Drawings FIG. 1 is a sectional view showing a wheel disc which has just been pressed into a wheel rim by a hydraulic press.
FIG. 2 shows a hot-formed prior art wheel disc which has had its outer diameter machined in preparation for the wheel being pressed into a rim.
FIG. 3 shows the prior art disc of FIG. 2 pressed into a wheel rim and the damage caused to the rim and disc as a result of the press operation.
FIG. 4 shows a hot-formed wheel disc of the type used in the present invention which features an outside diameter having its finish unaltered from that which existed at the end of the forming operation.
FIG. 5 shows the disc of FIG. 4 pressed into a wheel rim and the smooth, undamaged surface area resulting on the wheel rim.
Description of the Preferred Embodiment Referring now to FIG. 1, there is shown a partially assembled wheel 10 including a drop-center rim 12 having a disc 14 pressed into a cylindrical center section 16 thereof. The disc 14 is hot-rolled so as to be somewhat dish-shaped and includes an axially extending annular flange 18. The disc 14 is thicker than the rim 12 and the press fit between the rim and disc is relatively large in order that the disc is able to round out the rim in those instances where the rim is oval-shaped.
For example, the disc 14 should be about .25 inch thicker than the wheel rim 12 and the outside diameter of the disc flange 18 should have an as-formed outside diameter which is between .080 inch and .300 inch greater than the inside diameter of the rim center section 16.
The rim 12 is shown supported on a fixture 20 including a cylindrical base 22 having three equi-spaced centering blocks 23 fixed to the periphery thereof. An elevated cylindrical center portion 24 of the fixture 20 forms a stop for properly positioning the disc 14 as the latter is being pressed into the rim 12 by a hydraulic press including a cylindrical foot 26 carried by the lower end of a hydraulic piston 28.

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1 A prior art wheel disc 30 is shown in FIG. 2 and differs from the disc 14 shown in FIG. 4 only in that the sutside diameter of its flange has been machined, as at 32 as opposed to the as-formed finish 34 located on the outside diameter of the flange 18. Typically, the machining operation would reduce the diameter of ~he disc from its as-formed diameter by from .1 inch to .15 inch.
Referring now to FIG. 3, it can be seen that when the prior art wheel disc 30 is pressed into the rim 12 a plurality of l~ axially extending gouges or score marks 36 are caused in a surface area 38 of the rim 12 traversed by the flange of the disc 30. Similar gouges or scorè marks 40 also appear in the outside diameter of the flange of the disc 30. Often, chunks of material are actually torn from the rim 12 a~ the top ends of 1~ the gouges 36 and often chunks of material are also torn from the disc 14. The gouges left on the rim vary in severity but typically include marks which are .080 inch deep, .625 inch wide and several inches long. A surface containing such gouges is too rough to be acceptable from an appearance standpoint and 2D must be repaired by applying weld material and then grinding off rough spots; and a surface containing numerous of the most severe gouges may even be unacceptable from a strength standpoint.
~eferring now to FIG. 5, the disc 14 is shown pressed into the rim 12. Even though the flange 18 of the disc 14 has an as-formed outside diameter which is greater than the machined outside diameter of the flange of the prior art disc 30, a surface area 42 of the rim center section 16 traversed by the disc flange 18 as the disc 14 was pressed into the rim 12 is left in a nicely polished condition similar to that which is produced by a burnishing operation. Furthermore, it has been observed that a maximum force of about 75 tons must be exerted by the hydraulic press in order to press the disc 30 into the rim 12 while only from 25 to 50 tons is required for pressing in the disc 14.
The reason for the improved results achieved by using the disc 14 is not fully understood but it is thought that the as-rolled flange surface of the disc 14 acts to lubricate the flange-rim interface as tbe disc is pressed into the rim.

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Claims

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE PROPERTY OR PRIVILEGE
IS CLAIMED ARE DEFINED AS FOLLOWS:

1. A method for assembling a hot-rolled disc into a cylindrical center section of a wheel rim with the disc having about twice the thickness of the rim and having an annular, axially extending flange which has an outside diameter between .18 and .25 inch greater than an inside diameter of said cylindrical center section, comprising: leaving the finish of the inside diameter of the cylindrical center section in an unfinished state; leaving the finish of the outside diameter of the disc flange in an "as-rolled" state and pressing the disc into the cylindrical center section of the wheel rim and thereby smoothing the surface area of the rim traversed by the disc flange.