CA1172394A

CA1172394A - Elastic solid tire

Info

Publication number: CA1172394A
Application number: CA000410795A
Authority: CA
Inventors: Rolf Mahling; Ernst Danzeglocke
Original assignee: Continental Gummi Werke AG
Current assignee: Continental AG
Priority date: 1981-09-03
Filing date: 1982-09-03
Publication date: 1984-08-07
Also published as: EP0073975A2; ES276129Y; DD204071A5; IE56076B1; ATE52463T1; EP0073975A3; DE3280169D1; CZ278540B6; ES276129U; EP0073975B1; IE822155L

Abstract

ABSTRACT OF THE DISCLOSURE
A rubber mixture for producing solid rubber tires and a solid rubber tire produced using such a mixture.
Textile or metallic fiber particles arc placed in the rubber mixture, and thus in the rubber of the solid rubber tire. The fiber particles are bonded chemically to the surrounding rubber by a bonding system. The fibers are in-troduced into At least one layer of the solid rubber tire.
A resorcinol/hexamethylenetetramine system may he used as the bonding system.

Description

~ 3~'~

The present invention ~ela~es to R ~lbber rnixture, in which fibers are introduced, Eor producing solid rubber tir~s~ and to a solid ~ubber tire produced therewith. The tire is made of rubber or rubber~like elas-~omeric material, and comprises one or more layers, wqth the fibers being present in at least one of the layers.
The cost of producing a solid rubber tire is reduced in a known manner by introclucing fibers into the rubber rnix-~ures for solid tires, ~nd th~ thus procluced vulcanized 1~ goods are more rigid or harder The fibers are pla~ed in various layers o the solid rubber t-Lres depPDding upon the application oE the latter. With such solid tires, which comprise a tread rubber9 a resilient rubber CUShiOIl, and a base ring of tough-hard rubber, it is important especially -for the base ring rubber, which may have skeel wire inserts extending thereln 3 to provide an extremely tough~hard mix-ture so that the tire, mounted for instance with a press fit upon a cylindrical surface of the rim, maintains a secure seat even during high loading thereof. Included as 20 mater;als for fibers ko be introduced for e~ery type of solid tire are, for instc~nce, mineral fibers such as as-bestos; synthetic fibers such as rayon7 nylon, polyeth~lene, etc.; animal fibers su~h as wool; and plant fibers such as wood. Metal, glass, and carbon can also be suitable.
It has been proven wlth Icnown solid tires having iber particles placed iIl the base ring rubber, that the iber particles begin to shift within the rubber mixture because of the continuously changing loading during operation;
these fîber particles then d~mage the surrounding rubber be-30 ca~se o this interior mo~ement, so that the rubber fre-quently already after a short time becomes brittle (or ~lawed)~ thus endangering the seating of the tire on the rim body.
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It is therefore an obîec~ oE ~he pre~ent illvention to provide a rub~er mixture for a solîd tire, and a solid tire itself, with which a secure seating on the riln, and a re~
liable operation, are assured.
This object, and other objects and advantages of the present invention, will appear more clearly from t~e fol-lo~ing specification in connec~ion with the accorllpanying drawin$, in which:
Figure 1 is a radial partial section of one embofliment of a solid rubber tire according to the present inveDtion;
- Figure 2 is a fragmentary plan ~iew of a circum-ferential surface at the level of line II-II iD Figures and 3; and Fi~ure 3 is a radial partial section of a further embodiment of the inventive solid ~ubber tire.
By one aspect o~ this invention, there is provided a solid tire of elastomeric rnaterial, comprising a~ least o~e layer of the elastomeric material; and fibers disposed in at least one of the layers7 the fibers being chemioally bond-ed to surrounding elastomeric material by means of a bond-ing systemO
By a further aspect of this invention, there is pro-vided a rubber mixture for producing solid tires, the mix-ture comprising elastomeric material, fibers embedded in the elastom~ric material9 and a bonding system compatible with the fibers and the elastomeric rnaterial.
The bonding system is advantageously introduced di-rectly into the rubber mixtureO Due to the chemical bond-ing between the surface of the fibers and the adjoining rubber, the fibers are no longer present in the finished tire as 130s~ foreign bodies in the rubber9 so that a "sawing effect" can no longer be carried out b~ the fibers during inner movements thereof; insteadl the fibers fo~n

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3 9 ~a r.igidly connectecl unit with ~he rubber~
Tough-hard rubber mi~tures of prev:Lously unattain-able qualit~ for the base ring are attained with the present invention, so that solid tlres produced there~ith have a.
considera~ reater durability ancl useful lie.
Pursuant to one specific embc)diment of the presen~ in~
vention, the conventional metallic inserts, e.gl steel ~,~re cores, in the base rubber can be entirely elim:inated if fibers with a proportional wei.ght: of at lcast 5% of the ~^.7eight of the base ~ing are introcluced at least in the base ring rubber layer~ and i.E the lc~yer thiclcness of the base ring rubber layer is from lV% to 90% of the eross-sectional height of the tire. According to one preferred embodiment, the thiclm ess of the base ring rubber layer is approximately 50% of the cross-sectional height of the tire.
This const~lction is ~ased upon the realization that by embedding fibers in the base ring with a proport:ional weight of over 5%, in conjunction with a minirnurn thickness for the base ring layer, which depends upon the required 20 operational loading of the tire, such a good rigidity or nardness is attained that the heavy c~nd e~pensive steel ~Lre cores cc~n be entirely eliminated. To achieve a re~
liable rim seating, the mounted tire should have c~n inner diameter which, due to stretching, is about 0.5% to 10%
greater than in the non-mo~mted condition thereof.
The tire according to the present invention, asicle from a considerable weight reduction realized by elimina-tion of the steel wqre cores, primarily has the advantage of a simpler and less expensive production.
A further advantage is the not inconsiderable re-duction of resistance to rolling brought about primarily b~ the increasecl rigidityO
Furthermore, the teaching of the present invention . ~ 3 -i.i~23~1 is especially suitable ~or increasin~ the st~bili.ty o certain vehicles ~hich use solid tlres due to the bonded placernent of fibers in the resilient rub~er cushion~
Technical advantages can e~en be achieved accord~ng to the present invent:ion with soli.d tires having only one rubber layer, or having two different rubber layers.
Referring now to the drawing in detai.l, the solid tire is made of rubber or rubber~l.il.~e materials, c~nd essent;ally comprises three layers, narnely a wear-resistant tread rubber I, a resili.ent rubber cushion 2, and a b~se ring 3 of tough-hard rub~er with or without steel wire or band cores 4 embeclded thereing the latter extending in the circumferential direction of the tire~
Fibers 5 are introduced in the rubber o the base rîng 39 and in the embodiment of Fig. 1 also in the resilient rubber cushion 2, the fibers 5 are chemically bonded to the adjacent rubber by means of a bonding system, which can, for example, be the Icnown resorcinol/hexa (hexamethyl-enetetramine) s~stem. The chemical bond is schematically illustra-ted in the drawing by dots in the immediate vicinity of the fibers 5.
The solid tire according to Fig. 3 differs from that according to Fig. 1 in that the base ring 3 is enlarged to approximately hal~ the cross-sectional height of the tire, and is no longer provided with steel wire cores, further-more, the bonded embedded fibers are located exclusively in the base ring 3. Naturally, however, if required, the fibers can also be provid~d in the other ~wo la.yers.
Also~ other thickness relationships in the range of between 10% and 90% of the cross-sectional height of the tire are possible for the base ring 3; such relationships depend upon the respective application or purpose o~ the tireO
The proportional weight of the fiber material 5 to 'J ;~

the total weight o~ the base ring 3 shoulcl ~e at least 5%.
Proportions i.n a range of l5C/o to 20% have proven to be advantageous.
The use of previously conve~ltional steel wire cores is no longer necessary with a sol'id tire having the charac-teristics described in the forego-ing paragraphs; nonethe~
less, the possibility that the ti-re coulcl become loosened from the rirn is not ignored. ~le tire is mounted by a press fit upon a non-illustrated rim, with the inner dic~neter of 10 the tir~ being approxima~ely 015 ~o 10%, and preEerahly approximately 5%, greater thc~n in the non~mounted concl.ition o~ the tire to ach:;eve a preloading or prestressing for a secure seating of the mounked tire. Further fastening Means for a secure seating o:E the tire on the rim are then not necessary.
Synthetic fiber material, for exarnple a mixture of rayon and nyl~n, is preferably used or the fibers 5. It is especially adv~ntageous to o'btain the fibers 5 ei~her from scrap from the manufacture of tire cord fabr.ic7 or 2Q from the cord ~abric o:~ used tires~
The fibers 5 should have a length of 1 to 5 rnm, and the aspect ratio (the ratio of the leng~h to the diameter) should be at least 20~
The small or even cornminuted fibers 5, as well as -the materials for the associated bonding system~ are added to the rubber mixture prior to calendering, so that the fiber particles 5, initially introduced in a non-oriented or random manner9 are aligned or oriented during the calendering process, prefera~ly in t'h~ direction of move-30 ment of the rollers. Consequently, during manufacture ofthe solid tire, the fiber partic'les 5 are preferably at least predominantly disposed in the circumerential direc-tion~ so that an especially high rigidity or hardness is 2 3 3 ~1atta-ined in the base ring 30 It sh.ould be notecl that l:f necessary the fiber particles S can also comprise metallic mater:ial, so that for example the brass~plated steel ~ires from used pneu-matic tires cc~n be utilized~ Maturally, in sueh a si~la-tion a Icno~l bonding systeril for brass and steel wou].d be usedO
Fibers 5 of other mat~rials ean also be usedO In eaeh case it is import~mt that to the assoeiated rubber mixture a bonding system be added whieh effeets a strong chemical bond between the selectecl :~iber material and the adjacent rubber.
The aorementionecl introduction of fiber ~aterial also into the resili.ent rubber cushîon ~ has proven espeeially useul with solid tires whieh are providecl for fork lifts having great lifting heights. In such cases the stability of the vehiele is considerably inereased by the bonded introduetion of fiber particles 5 into the rubber eushion 2.

Claims

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

l. A solid tire of elastomeric material, com-prising:
at least one layer of said elastomeric material;
and fibers disposed in at least one of said layers, said fibers being chemically bonded to surrounding el-astomeric material by means of a bonding system so that an especially strong chemical bonding of said fibers to said elastomeric material results therefrom,
2. A solid tire according to claim l, said tire comprising three layers, namely a wear-resistant tread rubber layer, a resilient rubber cushion, and a base ring of tough-hard rubber in which there are embedded steel insert cores which extend in the circumferential direction of the tire; and in which said fibers are bonded via said bonding system to the rubber of at least one of said base ring and said rubber cushion.
:3. A solid tire according to claim l, in which said bonding system is a resorcinol/hexamethylenetetra-mine system.
4. A solid tire according to claim 1, in which said fibers are 1 to 5 mm long.
5. A solid tire according to claim l, in which said fibers have an aspect ratio ( ratio of length to diameter) of at least 20.
6. A solid tire according to claim 1, in which said fibers comprise synthetic material.
7. A solid tire according to claim 6, in which said synthetic material is selected from the group con-sisting of rayon, nylon, and mixtures thereof.
8. A solid tire according to claim 1, in which said fibers comprise metallic material.
9. A solid tire according to claim 1, in which said fibers are at least predominantly disposed in the circumferential direction of said tire.
10. A solid tire according to claim 1, said tire comprising three layers, namely a wear-resistant tread rubber layer, a resilient rubber cushion, and a base ring rubber layer; said fibers being disposed at least in said base ring rubber layer with a proportion-al weight of at last 5% of the weight of said base ring layer; the thickness of said base ring rubber layer being from 10 to 90% of the cross-sectional height of said tire.
11. A solid tire according to claim 109 in which said fibers in said base ring layer have a pro portional weight of is to 20% of the weight of said base ring layer.
12. A solid tire according to claim 10, in which the thickness of said base ring layer is approx-imately 50% of the cross-sectional height of said tire.
13. A solid tire according to claim 10, in which the inner diameter of said tire when mounted on a rim via a press fit is approximately 0.5 to 10%, in greater than the inner diameter of said tire in a non-mounted condition in order to achieve a preloading in the mounted condition.
14. A solid tire according to claim 13, in which the inner diameter of said mounted tire is ap-proximateIy 5% greater than the inner diameter of said tire in a non-mounted condition.
15. A rubber mixture for producing solid tires, said mixture comprising:
elastomeric material;
fibers embedded in said elastomeric material; and a bonding system compatible with said fibers and said elastomeric material.