AU618980B2 - Tyre construction - Google Patents

Description

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PCT

wl OPI DATE 19/07/89 APPLN- ID 28141 89 INTERNATIONAL APPLICATIC (51) International Patent Classification 4 7/10, 23/18, 23/19 (21) International Application Number: PCT/AU88/00470 (22) International Filing Date: 8 December 1988 (08.12.88) (31) Priority Application Numbers: PI5903 PI 6380 (32) Priority Dates: (33) Priority Country: 15 December 1987 (15.12.87) 19 January 1988 (19.01.88) (74) Agents: HARWOOD, Errol, John et al.; Wray Associates, P.O. Box 6292, East Perth, W.A. 6004 (AU).

(81) Designated States: AT, AT (European patent), AU, BB, BE (European patent), BG, BJ (OAPI patent), BR, CF (OAPI patent), CG (OAPI patent), CH, CH (European patent), CM (OAPI patent), DE, DE (European patent), DK, FI, FR (European patent), GA (OAPI patent), GB, GB (European patent), HU, IT (European patent), JP, KP, KR, LK, LU, LU (European patent), MC, MG, ML (OAPI patent), MR (OA- PI patent), MW, NL, NL (European patent), NO, RO, SD, SE, SE (European patent), SN (OAPI patent), SU, TD (OAPI patent), TG (OAPI patent), US.

Published With international search report.

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-j (71) Applicant (for all designated States except US): AL- TRACK LIMITED [AU/AU]; 160 St. George's Terrace, Perth, W.A. 6000 (AU).

(72) Inventor; and Inventor/Applicant (for US only) JARMAN, Brian [GB/AU]; 1 Steele Road, Sorrento, W.A. 6020 (AU).

(54) Title: TYRE CONSTRUCTION (57) Abstract A non-pneumatic tyre (10) comprising an annular body of resilient construction having a radially outer peripheral portion (19) and a radially inner peripheral portion A cir- 23 cumferential web extends between, and is connected to, the radially inner and outer portions. To each side of the circumferential web there is a set of circumferentially spaced ribs (45, 49).

Each rib extends between and is connected to the radially inner and outer portions of the tyre. Each rib is also connected to the 27 web. A characterising feature of the tyre is that the circumferential web comprises consecutive web sections (53) extending in alternate directions.

i '1 WO 89/05736 PCT/AU88/00470 -1 "Tyre Construction" FIELD OF THE INVENTION THIS INVENTION relates to a tyre construction and in particular to a tyre construction which is non-pneumatic.

BACKGROUND OF THE INVENTION There are various proposals for construction of tyres which are non-pneumatic so as to avoid the problem of puncturing and which provide acceptable cushioning and performance characteristics.

Where the proposals are concerned with solid tyres Sconstructed predominantly from elastomeric material, a difficulty arises in dissipating heat generated in the tyres, and resultant accumulation of heat may lead to iidegradation of the tyre material.

Other proposals overcome or avoid the problem of heat accumulation by providing cavities in the body of the tyre. The cavities not only reduce the overall mass of the tyre so as to reduce the extent of heat generated but also enhance heat dissipation. In certain proposals, the cavities are so arranged as to result in the formation of a load carrying and supporting structure within the tyre between its inner and outer peripheries. Such a structure within the tyre is arranged to have load bearing capabilities while also being capable of deformation to provide cushioning. Several such proposals are disclosed in European Patent Application Nos. 0159880 and 0245789 and each comprises a structure in the form of circumferentially spaced apart ribs interconnected by a central web which is generally planar and extends circumferentially around the rotational axis of the tyre.

-2- With this structure, each section of the central web between neighbouring ribs has a longitudinal extent aligned with the direction of rotation of the tyre and consequently may be vulnerable to collapsing when the tyre is subjected to lateral forces, particularly during cornering.

SUMMARY OF THE INVENTION The present invention seeks to provide a novel and useful tyre construction which improves the stability of the tyre.

In one form the invention resides in a non-pneumatic tyre comprising an annular body of resilient construction i having a radially outer peripheral portion, a radially inner peripheral portion, a radially compressible circumferential web extending between and connected to the i radially inner and outer portions, and an intermediate portion between the radially outer and radially inner peripheral portions, said intermediate portion being provided on each side of the circumferential web with an arrangement of radially compressible ribs, said arrangements having evenly matched numbers of ribs disposed in a complementary manner, each rib extending between and being connected to the radially inner and outer peripheral portions and to the circumferential web S"wherein the circumferential web comprises consecutive web sections extending in alternate directions, and each rib comprises a radially inner and a radially outer rib portion formed integrally and disposed angularly with respect to each other to define a zone about which the ribs can flex thereby to provide a cushioned, durable tyre.

3 Preferably said web sections comprises inner and outer web portions formed integrally and disposed angularly with respect to each other to define a zone about which the web can flex.

Preferably, said consecutive sections of the web define a zig-zag formation.

Preferably, said ribs disposed on one side of the circumferential web are sited in an offset manner from the complementary ribs on the other side of the circumferential web, so that the ribs are alternately disposed with respect to each other.

Preferably, the ribs are connected to the web at the ends of said web sections. Where the consecutive web sections define a zig-zag formation as aforesaid, the ribs are connected to the web at the junctions between consecutive straight sections of the zig-zag formation.

Preferably, the tyre is provided with passages, each defined between said inner and outer peripheral portions, between two adjacent ribs and between said circumferential web, and each said passage opens out into a sidewall of the tyre, wherein said passages are offset in relation to each other such that each passage on one side of the circumferential web extends into the region between neighbouring passages on the other side of the circumferential web thereby defining a partition between the neighbouring passages.

Preferably, the tyre further comprises a reinforcing means encased in said radially inner peripheral portion, said reinforcing means comprising an annular band of one piece construction concentric with the annular body of said 9 9.

9e 9 9 9 9 9.4 9 i ~t 4tyre, and a circumferential bead provided on each side of said radially inner portion, said circumferential beads being adapted to be releasably engaged by a support rim for the tyre, the sides of the annular band being configured to provide reinforcement for said circumferential beads.

The tyre may be of unitary construction or segmental construction.

In another form the invention resides in a non-pneumatic tyre comprising an annular body of resilient construction having a radially outer peripheral portion, a radially inner peripheral portion and an intermediate portion between the radially outer and the radially inner portions, said intermediate portion being provided on each side of the circumferential web with an arrangement of circumferentially spaced apart passages, said arrangements S having evenly matched numbers of passages disposed in a complementary manner, the passages on one side of the circumferential web corresponding to the passages on the other side of the circumferential web, whereby the passages open out into the corresponding sidewalls of the tyre and extend inwardly across the tyre and terminate at the intermediate portion of the circumferential web, said complementary passages being offset in relation to each other such that each passage on one side of the circumferential web extends into the region between the neighbouring passage on the other side of the ircumferential web, wherein a rib is defined by each portion of the annular body between neighbouring passages on either side of the circumferential web, wherein consecutive web sections extend in alternate directions, each rib comprises an inner and an outer rib portion formed integrally and disposed angularly with respect to

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4a each other to define a region about which the ribs can flex, and each web section comprises an inner and an outer rib portion formed integrally and disposed angularly with respect to each other to define a zone about which the web section can flex.

In still another form the invention resides in a non-pneumatic tyre comprising an annular body of resilient construction having a radially outer peripheral portion, a radially inner peripheral portion for mounting on a rim, and an intermediate portion between the radially outer and radially inner portions, said radially inner portion having a circumferential bead provided on each side thereof for engagement with the rim, a reinforcing means encased in said radially inner portion, said reinforcing means having sides configured to provide reinforcement for said circumferential beads, said intermediate portion ***!being provided on each side of the circumferential web with an arrangement of passages, said arrangements having evenly matched numbers of passages disposed in a complementary manner, the passages of each side of the circumferential web open out into the corresponding sidewall of the tyre and extend inwardly across the tyre and terminate at the intermediate portion of the circumferential web, said passages are offset in relation to each other such that each passage extends into the region between the neighbouring corresponding passages, and wherein a rib is defined by the portion of the annular S body between the neighbouring corresponding passages, and a web section is defined by a further portion of the annular body between each passage and between each neighbouring corresponding passage wherein consecutive web sections extend in alternate directions, each rib comprises an inner and an outer portion formed integrally 4b and disposed angularly with respect to each other to define a region about which the ribs can flex, and each web section comprises an inner and an outer portion, formed integrally and disposed angularly with respect to each other to define a zone about which the web section can flex.

BRIEF DESCRIPTION OF THE DRAWINGS The invention will be better understood by reference to the following description of one specific embodiment thereof as shown in the accompanying drawings in which:- Fig. 1 is a side view of the tyre according to the embodiment; Fig. 2 is a cross-sectional view of the tyre according to the embodiment;

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loeeo LWO 89/05736 PCT/AU88/00470 Fig. 3 is a fragmentary side view of the tyre, on an enlarged scale; Fig. 4 is a section along the line 4-4 of Fig. 2, on an enlarged scale; Fig. 5 is a section along the 1Ine 5-5 of Fig. 2, on an enlarged scale; Fig. 6 is an elevational view of the tyre with various parts cut away to reveal the internal construction of the tyre; i Fig. 7 is a schematic view showing the tyre according to the embodiment fitted onto a support rim with a portion of an outer part of the support rim cut away to reveal an inner part of the rim; and i Fig. 8 is a section along the line 8-8 of Fig. 7.

DESCRIPTION OF PREFERRED EMBODIMENT The ernbodinent shown in the drawings is directed to a non-pneumatic tyre 10 which is to be mounted onto a support rim 11. The support rim is shown in Figs. 7 and 8 i and is constructed in two parts being an inner part 12 and an outer part 13. The two parts 12 and 13.3 can be separated to facilitate mounting of the tyre onto the rim and thereafter secured together by any suitable means, such as circumferentially spaced apart bolts 14, to maintain the tyre on the rim.

The tyre 10 comprises an annular body 15 of composite construction having a radially inner portion 17, a radially outer portion 19 and an intermediate portion 21 between the inner and outer portions. The radially inner portion 17 is adapted to be mounted on the support rim 11, as best shown in Fig. 7 of the drawings. The radially outer portion 19 defines a running surface 23 having a tread formation 25 for gripping engagement with the ground. The outer portion 19 is also provided with a zone WO 89/05736 PCT/AU88/00470 -6which is reinforced with breaker elements 27 of known type. The radially inner portion 17 of the body is provided with reinforcing means 29 in the form of an annular band which is concentric with the tyre and which extends a substantial part across the width of the radially inner portion. The annular band 29 is constructed of metal and in turned back on itself at its sides in an arcuate fashion to provide circumferential ribs 31 which serve to reinforce circumferential beads 33 provided at the sides of the radially inner portion 17 of the tyre. The beads 33 are adapted for engagement with the support rim 11, as best seen in Fig. 7 of the drawings. The annular band 29 is provided with a plurality of holes 35, as shown in Fig. 6 to facilitate bonding of the elastomeric material to the band. The band 29 serves to reinforce the radially inner portion 17 of the tyre so that it can be securely fixed to the rim.

The body 15 of the' tyre is of composite construction, being formed predominantly of an elastomeric material (such as rubber) which is firm yet resiliently flexible and having the breaker elements 27 and the reinforcing means 29 encased therein.

The intermediate portion 21 of the tyre is provided with two sets of passageways 37 and 39, one corresponding to each side of the tyre. The passageways in each set open onto their corresponding sides of the tyre at respective openings 40 and 41 and extend across the tyre towards the other side, terminating at 43 inwardly of said other side.

The set of passageways 37 are circumferentially spaced apart around the tyre whereby a partition 45 is defined between neighbouring passageways. Similarly, the passageways 39 are circumferentially spaced apart around the tyre whereby a partition 49 is defined between J 1.

WO 89/05736 PCT/AU88/00470 -7neighbouring passageways. The partitions 45 and 49 define rib members which exi:end between the radially inner and outer portions 17 and 19.

The two sets of passageways are circumferentially offset in relation to each other such that each passageway in one set extends into the region between neighbouring passageways in the other set and vice versa, as best seen in Fig. 6 of the drawings. The inner portions of the passageways converge in the inward direction to 43, also as best seen in Fig. 6. With such a construction, there is defined a further partition 53 between each passageway in one set and a neighbouring passageway in the other set.

The partitions 53 constitute web sections which co-operate to define a web which extends circumferentially around the tyre and which extends between the radially inner and outer portions of the tyre. In this embodiment, the web sections define a web which is of zig-zag formation. Also with this arrangement, the ribs defined by partitions and 49 are integrally connected to the web defined by partitions 53 at the ends of the partitions 53.

Because of the resiliently flexible nature of the elastomeric material from which the body is predominantly constructed, the ribs and web sections are capable of flexing and this feature assists in providing cushioning to the tyre. The zig-zag formation of the web sections 53 enhances the stability of the tyre and resists uncontrolled collapse of the web defined by such web sections. To enhance the flexing action, the ribs defined by partitions 45 and 49 between neighbouring passageways in each set are configured so as to be somewhat angular in profile to define a zone 59 at which the ribs can resiliently flex. Similarly, the web sections defined by partitions 53 are configured so as to be somewhat angular i Fl i '1 8 in profile to define a zone 61 at which the web sections can resiliently flex. The ribs and web sections thus have upper and lower portions that meet at a point of angularity to define the flex zones 59 and 61. As can be seen in the drawings, the upner and lower rib portions and web sections have generally parallel side faces extending transversely to the rotational direction of the tyre in the region of angular disposition of each rib.

From the foregoing, it is evident that the present invention provides a tyre which is non-pneumatic but which is capable of flexing to provide a cushioned ride.

It should be appreciated that the scope of the invention is not limited to the scope of the embodiment described.

For instance, rather than being of unitary construction, the body may be constructed as a plurality of segments which can be positioned around and affixed to the support rim. With this arrangement, segments can be replaced on an individual basis in the event of damage.

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Claims (10)

1. A non-pneumatic tyre comprising an annular body of resilient construction having a radially outer peripheral portion, a radially inner peripheral portion, a radially compressible circumferential web extending between and connected to the radially inner and outer portions, and an intermediate portion between the radially outer and radially inner peripheral portions, said intermediate portion being provided on each side of the circumferential web with an arrangement of radially compressible ribs, said arrangements having evenly matched numbers of ribs disposed in a complementary manner, each rib extending between and being connected to the radially inner and outer peripheral portions and to the circumferential web wherein the circumferential web comprises consecutive web sections extending in alternate directions, and each rib .e.o comprises a radially inner and a radially outer rib portion formed integrally and disposed angularly with respect to each other to define a zone about which the ribs can flex thereby to provide a cushioned, durable tyre.

2. A ty:e according to claim 1 wherein said web o sections comprises inner and outer web portions formed o e integrally, and disposed angularly with respect to each other to define a zone about which the web can flex. .oe oeeoo

3. A tyre according to claim 1 or 2 wherein said ribs disposed on one side of the circumferential web are sited in an offset manner from the complementary ribs on the other side of the circumferential web, so that the ribs are alternately disposed with respect to each other. 1,N A 49Vs 'AIT

4. A tyre according to any one of the preceding claims wherein the ribs are connected to the web at the ends of said web sections. A tyre according to any one of the preceding claims wherein said consecutive web sections of the webs define a zig-zag formation. S6. A tyre according to claim 5 wherein said ribs are connected to the circumferential web at the junctions between the consecutive straight sections of the zig-zag formation of the circumferential web.

7. A tyre according to any one of the preceding claims which is provided with passages each defined between said inner and outer peripheral portions, between two adjacent ribs and between said circumferential web, and each said passage opens out into a sidewall of the tyre, wherein said passages are offset in relation to each other such that each passage on one side of the circumferential web S: extends into the region between neighbouring passages on the other side of the circumferential web thereby defining a partition between the neighbouring passages.

8. A tyre according to any one of the preceding claims further comprising a reinforcing means encased in said radially inner peripheral portion, said reinforcing means comprising an annular band of one piece construction S"concentric with the annular body of said tyre, and a circumferential bead provided on each side of said kradially inner portion, said circumferential beads being adapted to be releasably engaged by a support rim for the tyre, the sides of the annular band being configured to provide reinforcement for said circumferential beads. i, I ~~1 i -11

9. A tyre according to claim 8 wherein the annular band is perforated to facilitate bonding of the tyre to the annular band. A tyre according to any one of the preceding claims wherein the annular body is of unitary construction.

11. A tyre according to any one of claims 1 to 9 wherein the annular body comprises a plurality of segments.

12. A tyre according to any one of the preceding claims wherein the inner and outer rib portions have generally parallel side faces extending transversely to a rotational direction of the tyre in the region of angular disposition of each rib. i 13. A tyre according to any one of the preceding claims ii wherein the inner and outer web sections have generally parallel side faces extending transversely to a rotational direction of the tyre in the region of angular disposition oe o of each rib. S14. A non-pneumatic tyre comprising an annular body of I "resilient construction having a radially outer peripheral o• portion, a radially inner peripheral portion and an intermediate portion between the radially outer and the S"radially inner portions, said intermediate portion being provided on each side of the circumferential web with an arrangement of circumferentially spaced apart passages, said arrangements having evenly matched numbers of passages disposed in a complementary manner, the passages on one side of the circumferential web corresponding to the passages on the other side of the circumferential web, whereby the passages open out into the corresponding sidewalls of the tyre and extend inwardly across the tyre )AAA TI~:~pt S- 12 and terminate at the intermediate portion of the circumferential web, said complementary passages being offset in relation to each other such that each passage on one side of the circumferential web extends into the region between the neighbouring passage on the other side of the circumferential web, wherein a rib is defined by each portion of the annular body between neighbouring passages on either side of the circumferential web, wherein consecutive web sections extend in alternate directions, each rib comprises an inner and an outer rib portion formed integrally and disposed angularly with respect to each other to define a region about which the ribs can flex, and each web section comprises an inner and an outer rib portion formed integrally and disposed angularly with respect to each other to define a zone about which the web section can flex.

15. A non-pneumatic tyre comprising an annular body of resilient construction having a radially outer peripheral portion, a radially inner peripheral portion for mounting on a rim, and an intermediate portion between the radially outer and radially inner portions, said radially inner portion having a circumferential bead provided on each S: side thereof for engagement with the rim, a reinforcing means encased in said radially inner portion, said reinforcing means having sides configured to provide reinforcement for said circumferential beads, said intermediate portion being provided on each side of the circumferential web with an arrangement of passages, said arrangements having evenly matched numbers of passages disposed in a complementary manner, the passages of each side of the circumferential web open out into the corresponding sidewall of the tyre and extend inwardly across the tyre and terminate at the intermediate portion of the circumferential web, said passages are offset in 13 relation to each other such that each passage extends into the region between the neighbouring corresponding passages, and wherein a rib is defined by the portion of the annular body between the neighbouring corresponding passages, and a web section is defined by a further portion of the annular body between each passage and between each neighbouring corresponding passage wherein consecutive web sections extend in alternate directions, each rib comprises an inner and an outer portion formed integrally and disposed angularly with respect to each other to define a region about which the ribs can flex, and each web section comprises an inner and an outer Sportion, formed integrally and disposed angularly with respect to each to define a zone about which the web Ssection can flex. i S16. A non-pneumatic tyre substantially as herein described with reference to the accompanying drawings. .o it K j