CA1125815A

CA1125815A - Wheel rim

Info

Publication number: CA1125815A
Application number: CA275,501A
Authority: CA
Inventors: James L. Evans; John A. Main
Original assignee: Kelsey Hayes Co
Current assignee: Kelsey Hayes Co
Priority date: 1976-04-05
Filing date: 1977-04-04
Publication date: 1982-06-15
Also published as: DE2714646A1; GB1573953A; IT1084620B; DE2714646C2; FR2347211A1; BR7702130A; JPS52152002A; MX143755A; FR2347211B1

Abstract

ABSTRACT
A wheel rim construction that cooperates with the tire bead seat to in-sure retention of the tire, even under a "run flat" condition. The bead seat portion of the rim is formed with a plurality of circumferentially extending surface dis-continuities that cause deflection of the rubber of the tire bead to form a mechanical interlock. The discontinuities are formed during the roll forming of the wheel rim by forming portions of the roll that cause permanent deformation of the rim material to generate the discontinuities.

Description

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This invention relates to a wheel rim and method of constructing sllch a wheel rim that assists in seating of the tire.
A wheel rim construction should be clesicJned to permi~
easy mounting of the tire, yet should al50 insure again~
movement of the tire bead relative to the wheel rim once mounted and inflated. Various wheel rim configurations have been proposed ~or achieving this purpose. In addition to the aforenoted desired results, the wheel rim should permit easy disassembly of the tire for servicing or replacement.
Substantially all of the wheel rim constructions are a compromise to achieve all of these effects. It is also desirable if the rim will cooperate with the tire bead in such a way as to prevent the tire from leaving the rim in the event of a "run flat" condition. That is, it is desirable if the tire will be retained on the rim even though it is :~ully deflated so that the owner may drive the vehicle to a place wherè it may be serviced.
` ~ United States Patent No. 3,977,727 issued to William A Glasenapp et al, teaches two ways in which a wheel rim may be modified to prevent a pneumatic tire ~rom disengaging the rim upon the loss of air pressure. Glasenapp teaches cutting "barbs" into the tire bead seat portion of the wheel using a chisel type tool or as an alternative, cutting circumferential "knurls" into the bead seat. By both of these techniques the cut-ting operation removes metal from below the intended bead seat surface thereby weakening the rim structure in the bead seat region.
Broadly speaking, therefore, the present invention provides in a wheel having an annulax rim por-tion with a pair of axially spaced annular flanges, an annular well portion intermecliate the flanges and an annular imperfora-te, bead seat b ~zs~

portion adjacent e~ch flange and axially spaced from the well po.rtion, each bead se~at poxti.on havinc~ a radially outer, annular surface for seating the base of each bead por-tion of a pneumat:ic tire, the .i.mprovement comprisiny at least two axially spaced apar-t circumEerentially con-tinuous radially outward projec-ti:ng protuberanc~s risi.ny from each annular bead seat surface such that the section thickness of each bead seat is not diminished, each pro-turbance comprising a radially outwardly projecting side, the side having at least a portion thereof normal to the wheel axial centerline, and a descending surface extend- !
ing from the radially projecting side sloped radially in-wardly and axially toward sa~d annular well, the descending surface terminating at the intersection of the descendiny surface and the annular bead seat surface, said descending surface permitting movement of the tire bead axially there~
over away from the wheel well upon inflation of said tire whereby the tire bead portion becomes locked between said radially outward extending flanges and said radially out-ward pro~ecting sides o:E said protuberances by compression of the bead elastomer therebetween.
Fiyure 1 is a partial cro5s-sectional view o~ a wheel rim and associated tire embodying this invention Figure 2 is an enlarged cross-sectional view of the area encompassed by the circle 2 in Figure 1~
Figure 3 is a cross-sectional view showing the me-thod .

~zs~s of forming of the wheel rim bead seat~
Figure 4 diagrammatically shows the yeometry of the projection cross-section and its pre:Eerred orientation with o-ther wheel parameters.
In the drawings, the refexence nume~al 11 indicates generally a drop center wheel rim embody.ing this invention.
The wheel rim 11 includes an annular well or a drop center portion 12. At the axial outer periphery of the wheel 11, a ~irst annular imperforate tire bead seat portion 13 is formed, which terminates in a radially outwardly ex-tending flange 1~.
At the axial inner side of the drop center 12, an elongated flange 15 is formed that terminates in a second annular imperforate tire bead seat portion 16. The bead seat portion 16 also terminates in a radially outwardly extending flange 17.
A pneumatic tire, preferably of the tubeless type, identified generally by the reference numeral 18, is mounted on the wheel rim 11. The tire 18 has inner and outer beads 19 and 21 that cooperate wi-th the wheel bead seats 13 and 16, respectively.

2~ In order to insure against accidental displacement of the tire bead portions 19 and 21 from the bead seats 13 and 16, an improved retention means is provided, which may be best understood by reference to Figure 2. In Figure 2 only the bead seat portion 13 is described and illustrated in detail. It is to be understood that -the bead seat portion 16 is of substantially identical construction. The tire bead 1~
has a heel portion that contacts the upper surface of the rim bead seat 13 over a substantial portion of its length. Three inclined surface discontinuities in the form of upstanding ridges 22, 23 and 24 are formed completely around the circumference of the portion of the bead sea-t 13 contacted by the tire bead 19. The ridges 22, 23 and 2~ have substantially ~l~S~

the same shape and are of a generally riyht triangular configuration.
Referring to Figure 4~ generally showing the geometry of a projecting ridge in accord with our invention, it is seen that radially extending side 41 i~ essentially normal to khe wheel base line 39 which is parallel to the wheel's axial centerline. S~nce the upper surface 38 of the bead seat portion 13 is inclined at a slight (approximately 5) angle C to the horizontal (base line 39), the side 41 will be slightly displaced from a right angle with respect to the upper surface 38 of the bead seat portion 13.
The included angle A, between the hypotenuse 40 and the radially extending leg 41 is preferably 60 to provide a ramp, or descending surface formed by hypotenuse 40, upon which the tire bead can slide up and over wnen the tire is initially inflated.
Because of the ridge'-s inwardly sloping hypotenuse 40, a ramp is provided over which the tire bead 19 may move relative to bead seat 13 in an axial outward direction. HoweverJ tire bead 19 is restricted from reverse movement in the inward direction. Thus by this action tire bead 19 is orced into a gripping relation between ridges 22, 23 and 24, and wheel flange 14 by pressurizing the pneumatic chamber of tire 18.
Upon loss of tire pressure, bead 19 is mechanically interlocked between flange 14 and ridges 22, 23 and 24 thus preventing disengagement of tire 18 from wheel 11 thereby providing a tire wheel assembly that will "run flat" and resist axial separation during high cornering loads.
Ridge 25 positioned inside of bead 19 and adjacent the bead tow further prevents inward movement of the bead _ 5 _ ..~

ll~S~S

relative to bead sea-t 13 by engaginy the toe should any inward bead movement beyin.
The method of form;.ng the wheel rim 11 ma~ be best understood by :re:Eerence to ~igure 3. An initial fo~min~ o~
the rim 11 is accomplished prior to a final rolling ope~a-t.ion.
In this final rolling opera-tion, the rim 11. is positioned between a pluralit.~ of rolls, only those associated with the bead seat porkion 13 being illustra-ted for ease of understanaing.
It is to be understood that the bead seat 15 is formed in a - 10 similar manner. The formation of the remainder of the wheel rim 11 is conventional and need not be described.
As is conventional in wheel forming operation, the rim 11 is positioned between an oute.r roll 27 and an inner roll 28. The rolls 27 and 2~ have facing surEaces that will, with suitable allowance for spring back, result in the desired configuration of the bead seat 13. Unlike previously proposed arrangements, however, the roll 27 is formed with reliefs 2g, 31, 32 and 33 for forming the ribs 22, 23~ 2~ and 25, respectively. The reliefs 29, 21, 32 and 33 are of slightly greater depth than the resulting ridges 22, 23, 24 and 25, to permit the spring back and to afford sufficient clearance for metal deformation. It has been found that during the rolling operation the pressure exerted by the roll 28 is sufficientl~
great so as to cause the metal of the wheel rim 11 to permenantly deflect into the g.rooves 29, 31, 32 and 33, of the roll 27.
It has been previously noted that the rib 25 does not contact the tire bead 19. This rib is formed to provide a surface of upset ma-terial at the axial inner peri.phery of -the bead seat portion 13. This rib in effect constitutes a dam that prevent inward displacement of the metal of the rim during the rolling operation to insure sharp definition of the ri.dges 22, 23, 2~.

'~12S8~5 It is to be understood that the foregoing description is that of a preferred embodiment of the invention~
Various changes and modificatlons may be made without depar-tincJ
from the spirit and scope of the invention as defined b~ the appended claims.

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Claims

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

1. In a wheel having an annular rim portion with a pair of axially spaced annular flanges, an annular well portion intermediate said flanges and an annular imperforate, bead seat portion adjacent each flange and axially spaced from said well portion, each bead seat portion having a radially outer, annular surface for seating the base of each bead portion of a pneumatic tire, the improvement comprising at least two axially spaced apart circumferentially continuous radially out-ward projecting protuberances rising from each annular bead seat surface such that the section thickness of each said bead seat is not diminished, each protuberance comprising a radially outwardly projecting side, said side having at least a portion thereof normal to the wheel axial centerline and a descending surface extend-ing from said radially projecting side sloped radially inwardly and axially toward said annular well, said descending surface terminating at the intersection of said descending surface and the annular bead seat sur-face, said descending surface permitting movement of the tire bead axially thereover away from the wheel well upon inflation of said tire whereby the tire bead por-tion becomes locked between said radially outward ex-tending flanges and said radially outward projecting sides of said protuberances by compression of the bead elastomer therebetween.

2. The improvement of claim 1 wherein said pro-tuberance has a triangular axial cross-section.

3. The improvement as claimed in claim 2 wherein said descending surface intersects said radially project-ing side of said protuberance at an angle of 60°.