CA1101773A - Pneumatic tire having a lubricant containing pocket integrally formed therein - Google Patents

Abstract

Abstract:
A pneumatic tire having a pocket filled with lubri-cant attached to the inner sidewall of the tire having a puncture sealant surrounded by an O-ring built into the inside wall of the pocket. The puncture sealant allows lubricant to be injected into the pocket by use of a syringe and eliminates the need for subsequent sealing of the pocket and leakage of lubricant from the pocket.

Description

The invention relates to a pneumatic tire having a lubricant-contain-ing pocket integrally formed therein.
The use of a lubricant-containing pocket formed in the sidewall of a tire makes it possible to run the tire after pressure is lost. The pocket is so positioned that when pressure is lost the pocket is ruptured and the lubricant enters the tire to prevent direct rubber-to-rubber contact. Rubber-to-rubber contact is undesirable as the friction is extremely high and upon prolonged running while flat, sufficient heat is generated to physically disintegrate the tire.
A run flat tire having a lubricant pocket formed in the sidewall is known in accordance of the prior art portion of claim 1, United States Patent 3,930,528, Harrington (1976). The patent discloses how to form the pocket in the sidewall, where to position the pocket and the lubricants which can be placed in the pocket. The patent discloses that the lubricant can either be injected into the pocket or the pocket can be split and sachets of lubricant inserted into the pocket.
Inserting sachets of lubricant into pockets is tedious, time-consuming and expensive. Retaining the pockets in a sealed condition and inject-ing the lubricant into the sealant pockets is difficult because after injection the lubricant tends to come back out of the hole and the hole is difficult to seal.
The invention as claimed is intended to provide a remedy. It solves the problem of the lubricant leaking out of the injection hole and difficulty of sealing the smeared hole with lubricant. Advantages offered by the invention are namely that the problem of lubricant leaking and hole sealing are completely eliminated.
The invention provides in a pneumatic tire comprising a carcass, a tread portion, two sidewall portions each terminating in a bead region, and at L7>73 least one of said sidewall portions comprising two transversely spaced layers of material which define therebetween at least one pocket integrally entirely within the tire structure, the layer on the inside of the tire being the inner liner, a lubricant composition in said pocket, the pocket being positioned in the tire in the region of a portion of the interior surface of the tire which contacts a second portion of the interior surface of the tire upon substantial underinflation or deflation of the tire during use thereof on a wheel such that the lubricant composition in said pocket is releasable therefrom onto the interior surface of the tire, the improvement characterized in that the inner liner is provided with a self-sealing part for the injection of lubricant, the self-sealing part comprising:
a) a rubber ring positioned in the inner liner b) a puncture sealant composition positioned in and surrounded by the ring.
One way of carrying out the invention is described in detail below in which:

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- 2 - ~ ~1773 Flgure l is a cross-sectlonal view of a tlre in accor-dance with the invention wlth a pocket 4 attached to the inner sidewall of the tire;
Figure 2 ls a magni~ied view of a valve used to ln-~ect lubricant into the pocket.
The flgures show a tire 2 comprising in lts basicdesign a pocket 4 formed in the sidewall of the tire wlth a lubricant 6 contained in the pocket and an outer pocket wall 8 ~ormlng a rupturable wall retaining the lubricant in the pocket. To wall 8 is a rubber rlng 10 for con-fining sealant 12. The comblnation of wall 8, ring 10 and sealant 12 form a valv~ for in~ecting lubricant 6. In accordan¢e with the invention, syrlnge needle 14 pierces sealant 12. Lubrlcant 6 is then in~ected through needle 14 until the pocket is filled.
Rubber ring 10 is an O-ring whlch is prererably at least partially cured ana ls used to con~ine sealant 12.
The O-ring to be used is pre~erably elastomeric. The hole in the 0-ring is preferably cyllndrical in rorm and has the diameter preferably from 2 to 5mm. The thlckness o~ the O-ring is preferably from 1 to 5mm and the outslde dlameter Or the O-rlng is prererably from 4 to 15mm.
Sealant 12 can be any conventlonal tlre puncture sealant and pre~erably lies under the sur~ace o~ wall 8.
Wall 8 thus provldes wiplng the sealant ~rom the needle when the needle is removed from the pocket. The speci~ic sealant whlch was used has the following formulation:
60 parts of ethylene propylene non-con~ugated diene rub-berl; 40 parts o~ ethylene propylene ethylldene norbornene2;120 parts o~ a high vlscosity para~inic oil3; 15 part~ Or Austln Black4, 2 parts o~ a diphenyl amlne-acetone lNordel 10j0 available ~rom duPont 35 2Epsyn 70 from Copolymer Rubber & Chemlcals Co., Baton Rouge, LA. It ls a zinc oxlde-phenolic resln curable gum.
3Avallable as Sunpar 20-80 from the Sun Oil Company ~Austln Black is bltuminous coal ~lnes available ~rom the Slab Fork Coal Co., and~or Columbia Carbon

3 ~ 3 reaction productS; and 12 parts Or a bromomethyl alkyl phenyl ~ormaldehyde resin6.
The polymers are added ~irst along with the carbon black to an internal mixer (Banbury mixer) then the oil was added ln small increments during mixing.
The tire was built in a conventional manner except for the construction of the pocket and the incorporation of the valve lnto the pocket. The construction of the pocket is described ln U.S. Patent 39930,528. The pocket was formed by painting two strlpes of a release coating on the lnner liner or applying strip~ of a releasing materlal between the lnner liners to conform to the width and length of the pocket. An 0-ring fllled with the punc-ture sealant was then lald on a section of the lnner liner coated with release agents. A second strip of inner liner, approximately 65mm wide was then lald over the release coat and extended beyond each slde o~ the release coat by approximately 5mm. The overlapped edges were stitched to the lnner llner. The inner liner was then posltioned on a building drum with the 65mm wide strlps directly in contact wlth the buildlng drum. The tire was then built in a conventional manner.
After the tire was built and cured,from 250 to 500 grams of a run flat lubricant was in~ected through the valve into the pocket; no leakage or seallng problems occurred.

sAvallable from Uniroyal Chemlcal, Naugatuck, Connecticut 6SPl055 brominated phenolic available ~rom Schenectady Chemlcals

Claims

Claims:

1. In a pneumatic tire comprising a carcass, a tread portion, two sidewall portions each terminating in a bead region, and at least one of said sidewall portions comprising two transversely spaced layers Or material which define therebetween at least one pocket integrally en-tirely within the tire structure, the layer on the inside of the tire being the inner liner, a lubricant composi-tion in said pocket, the pocket being positioned in the tire in the region of a portion of the interior surface of the tire which contacts a second portion of the in-terior surface of the tire upon substantial underinflation or deflation of the tire during use thereof on a wheel such that the lubricant composition in said pocket is re-leasable therefrom onto the interior surface of the tire, the improvement characterized in that the inner liner is provided with a self-sealing part for the injection of lubricant, the self-sealing part comprising:
a) a rubber ring positioned in the inner liner b) a puncture sealant composition positioned in and surrounded by the ring.