WO2016079571A1

WO2016079571A1 - A non-inflatable tyre assembly for a vehicle

Info

Publication number: WO2016079571A1
Application number: PCT/IB2014/066240
Authority: WO
Inventors: Jan Frederik LABUSCHAGNE
Original assignee: Prospect Sa Investments 121 Limited
Priority date: 2014-11-21
Filing date: 2014-11-21
Publication date: 2016-05-26

Abstract

A non-inflatable tyre assembly (10) for a vehicle comprising a rubber carcass (14) having a road engaging tread (16), the carcass (14) further having an inwardly projecting flange (24) on an inner circumference thereof the flange (24) having two outwardly directed lips (26) beatable in a channel (28) formed on a wheel rim (18), and means to secure the lipped flange (24) in the channel (28) of the wheel rim (18). The means to secure the flange (24) in the groove comprises two complimentary shaped flanges (30) extending partially over the channel (28) and over the lipped flanges (24) of the carcass (14). The wheel rim (18) is further provided as two components (18A; 18B) being secured to each other such that the flanges (30) of the wheel rim (18) operatively clamp the carcass flanges (24).

Description

A NON-INFLATABLE TYRE ASSEMBLY FOR A VEHICLE

FIELD OF THE INVENTION This invention relates to tyre assemblies for use on a range of vehicles from light vehicles through a large range of vehicles used for both on and off road applications, both motorized and unmotorized, and which are non-inflatable.

BACKGROUND OF THE INVENTION

Non-inflatable tyres, otherwise known as airless or non-pneumatic tyres provide many benefits over pneumatically inflated tyres. In particular, non- inflatable tyres have been beneficial in terms of reducing wear and providing a longer useful life as compared to inflated or pneumatic tyres.

Non-inflatable or airless tyres are described in WO2012/160534 which should be read together with this specification and which entire contents is incorporated herein by reference.

Non-inflatable tyres must be secured to the rim in alternative manners as compared to common inflatable or pneumatic tyres due to the structural differences between these tyres. For example, an inner peripheral steel band are incorporated into known non- inflatable tyres, commonly known as pressed-on type tyres. These types of tyres however require precision machining and the interference fit between the tyre and the wheel rim presents difficulties, in particular in installation and replacement of the tyres.

In other constructions, the tyres are provided as segments which are individually fixed to the wheel rim which yet further increases costs, installation and replacement time.

Tyres have also been provided which comprises of separate components such as an inner band and a covering, the inner band being more rigid in construction than the covering.

The carcass of the tyre of known construction, more particularly, the inner circumference of carcass almost invariably separates from the surface of the wheel rim or inner band, as the case may be, in particular where the tyres are under a high load. This results in open space/s forming between the carcass and the wheel rim. This results in the ingress of unwanted matter such as dust and rocks which damages both the tyre and wheel rim thereby negatively affecting the integrity and, as a consequence, the useful life of the tyre and rim. Further disadvantages of the current tyres are that the installation and replacement of the tyres are difficult, time consuming and the particular construction of known tyres, in particular the manner in which it is secured to the wheel rim results in high costs which makes the use of such tyres uneconomical.

The wheel rim of the tyre described in WO2012/160534 has provided an improved means to fit a non-inflatable tyre to the wheel rim. This system provides for the rim to include outwardly directed lips forming a shallow channel. Transverse T-sectioned ribs also extend at spaced intervals across the outer surface of the wheel drum to anchor the carcass to the rim and drum. These ribs also have flanges to assist in anchoring the moulded rubber to the rim.

OBJECT OF THE INVENTION

It is the object of this invention to provide a non-inflatable vehicle tyre which at least partially overcomes the abovementioned disadvantages and which provides an improved means of securing the tyre carcass to the wheel rim.

SUMMARY OF THE INVENTION

According to this invention there is provided a non-inflatable tyre assembly for a vehicle comprising a rubber carcass having a road engaging tread, the carcass further having an inwardly projecting flange on an inner circumference thereof, the flange being eatable in a channel formed on a wheel rim, and means to secure the flange in the channel of the wheel rim.

The invention further provides for the flange and channel to extend along the entire circumference of the carcass and rim respectively.

The invention further provides for the flange to be a lipped flange and for the means to secure the flange in the channel to comprise a flange extending partially over the channel and over the lipped flange of the carcass.

Further according to the invention the lipped flange comprises two lips projecting in opposite and outward directions and wherein the wheel rim includes two complimentary shaped flanges extending partially over the channel and over the lipped flanges of the carcass, and wherein the wheel rim comprises two components being secured to each other such that the flanges of the wheel rim operatively clamp the carcass flanges.

Further according to the invention the wheel rim includes peripheral flanges each having an inwardly projecting lip to locate in a groove formed on the outer surface of the carcass. The peripheral flanges may also include a series of inwardly projecting pins which operatively penetrates the rubber carcass to hold the tyre in place over the rim. Yet further according to the invention there is provided for the carcass to include a series of equally spaced passages extending transversely through the carcass to provide resilient waisted supporting ribs between the passages and wherein the passages are shaped as a figure eight.

BRIEF DESCRIPTION OF THE DRAWINGS _

These and other features of this invention will become apparent from the following description set forth below with reference to the accompanying drawings in which:

Figure 1 is a front perspective view of a non-inflatable tyre assembly according to the invention;

Figure 2 is a perspective rear view of the tyre assembly of figure

1 ;

Figure 3 shows a side plan view of the tyre assembly of figure 1 ;

Figure 4 shows a cross-sectional perspective view of the assembly along line IV-IV of Figure 3; Figure 5 shows a cross-sectional plan view of the assembly along line IV-IV of Figure 3 and detailed views of various components;

Figure 6 is an exploded side view of the assembly of figure 1 ; and

Figure 7 shows a perspective rear view of the wheel rim with a detailed view of pins on a flange of the wheel rim.

DESCRIPTION OF A PREFERRED EMBODIMENT OF THE INVENTION

As shown in the accompanying drawings a non-inflatable tyre assembly for a vehicle is generally designated by numeral 10.

The assembly 10 comprise a tyre 12 consisting of a carcass 14 having a road engaging tread 16 on the outer circumference thereof, and a wheel rim 18. It will be understood that the tread pattern of the road engaging tread 16 in the accompanying drawings is not specifically indicated in the drawings as this component may be varied according to different requirements across the wide range of vehicle tyres to which this invention is applicable.

The carcass 14 can be moulded by either injection or pressure moulding from the polymer selected to meet the particular purpose which the tyre is to meet. Essentially the polymers will comprise a mixture of natural rubber blended with a polybutadiene compound and tyre manufacturing experts will be able to select the desired mixture.

A basic vehicle tyre carcass can comprise a mixture to provide:

Tensile strength MpA - 20

Hardness IRHD - 65

Elongation at break % - 650

Rebound resilience % - 70

The compound values for the tread will be respectively 21 , 68, 600 and 55 and have an abrasion loss per mm³ of 85. These figures will of course vary for both environment and purpose of the tyre and experts in the field will determine final constituents with application of their knowledge to necessary experimentation.

The moulding operation will result in a carcass 14 having a body of resilient material with radially projecting ribs forming waisted passages 19 between them and connecting the wheel drum (not shown) to an outer band which will support the tread for the tyre 12.

In the illustrative wheel assembly 10, the passages 19 are shaped to result in the radially extending supporting ribs being waisted to provide passage in the shape of a figure 8 as shown. The tread portion can also be vulcanized to the carcass over an endless band of flexible steel cord plies (not shown). These plies are known in tyre manufacture and made from usually entwined hard steel galvanized or brass coated components to form the cord material so that it will be bonded between the tread and carcass through the apertures in the plies. This will contain any tendency of the tyre 12 to change shape under load and increase the securing of the tread to the carcass without adversely affecting the resilience of the complete wheel assembly. The plies will be laid so that the ends of each ply has a core end line extending at an angle across the carcass and spaced from that of the other plies. The core components of the outer two plies will be parallel to the axis of the tyre while the inner two plies will have component lines inclined in opposite directions at angles of about 30° to the tyre axis.

It is a particular feature of the tyre assembly that it includes characteristics to induce airflow across the width of the carcass and rim to prevent any overheating of the tyre and brake assemblies during use. This can be affected by rounding one radial edge of the operatively outside edge of passages or to fit scoops in the open passages, or by tapering the passages from the outside to the inside, causes a suction and therefore a constantly airflow through the passages for the duration of movement of the tyre. The passages 19 are preferably inclined from the operatively outside rearwardly to the inside and also slightly tapered. This induces flow through the passages as the wheel rotates and moves forward and secondly, to remove the finished product (wheel) fairly easy from the mould.

Also there is in the assembly the same cooling effect applied to the drum by directing airflow through the moving wheel onto the braking assembly.

The wheel rim 18 comprises two components 18A and 18B each of which include a peripheral flange 20 to operatively form a seat for the carcass 14. The peripheral flanges 20 furthermore are lipped to locate in a complimentary groove 22 on an outer surface of the carcass 14 to facilitate securing the tyre 12 to the wheel rim 18 and hold the tyre in place during operation.

An inner circumference of the carcass 14 is provided with a flange 24 having two oppositely and outwardly extending lips 26. The lipped flange 24 is operatively clamped and secured to the wheel rim 18 in a channel 28 formed in the wheel rim 18, the channel 28 having flanges 30 which partially extend over the lips 26 of the carcass flange 24 to ensure the clamping effect and secure the tyre 12 to the wheel rim 18.

To secure the tyre 12 to the wheel rim 18, the flange 24 of the carcass 14 is placed on rim component 18A such that the flange 30 of 18A extends over the lip 26 of the carcass 14. With the carcass 14 placed on component 18A, the flange 30 of rim component 18B is then placed over the lip 26 of the carcass 14. The rim components 18A and 18B are then secured to each other to operatively clamp and secure the tyre 12 to the wheel rim 18. The wheel rim 18 is then secured to the wheel axle of a vehicle (not shown) in the usual manner. The rim components 18A and 18B are secured to each other by a plurality of screws 32 engaged in a complimentary screwthread as shown. The components 18A and 18B may however be secured in any other suitable way without departing from the scope of the invention. The clamp formed as described above ensures that the inner circumference of the carcass 14 is properly secured to the wheel rim 18 and prevents the carcass 14 from separating from the wheel rim 18.

To further facilitate securing the tyre 12 to the wheel rim 18, a number of pins 34 are disposed on the flange 20 of the wheel rim 18 to operatively penetrate the rubber carcass 14 and keep the tyre 12 in position on the wheel rim 18. In this embodiment, sixty four pins are provided on each flange and are 5mm thick and 35mm in length. It will however be understood that the size and number of these pins may be varied according to the requirements of a particular assembly. It will also be understood that these pins 34 may be provided separate from or in addition to the lip on flange 20 of the wheel rim 18 to facilitate securing the tyre 12 to the wheel rim 18. To replace a tyre 12 when required, the wheel rim 18 is disengaged from the vehicle in the usual manner. The rim components 18A and 18B are separated and tyre 12 simply removed. A replacement tyre can thereafter be secured to the wheel rim 18 as described above and re-installed onto the vehicle. This enables simple replacement of a tyre 12 which may be done onsite without undue delay and downtime of the vehicle.

The embodiment of the invention described above may be modified by those skilled in the art in many ways to give different particular configurations of component details without departing from the scope of the invention. For example, the band of reinforcing described above may be provided by carbon fibre, nylon, woven fabric or the like. Further modifications will be made to suit the different requirements of the wide range of vehicles for which this tyre may be adapted. This is achieved without the problems encountered in the use of inflation.

The tyre assembly can also be adapted to be retrofitted onto existing vehicles without substantial modification to existing components. The tyre assembly 10 can also be up-scaled or down scaled to suite any purpose or demand in the tyre industry.

It is accordingly asserted that the abovementioned disadvantages of the prior art non-inflatable tyres are overcome. The means to secure the carcass 14 to the wheel rim 18 is provided to overcome the disadvantage of the carcass of the tyre almost invariably separating from the surface of the wheel rim, in particular where the tyres are under a high load. This prevents open space/s forming between the inner circumference of the carcass and the wheel rim and prevents the ingress of unwanted matter such as dust and rocks which damages both the tyre and wheel rim thereby negatively affecting the integrity and, as a consequence, the useful life of the tyre and rim.

The invention furthermore provides for easy installation and replacement.

Claims

1. A non-inflatable tyre assembly for a vehicle comprising a rubber carcass having a road engaging tread, the carcass further having an inwardly projecting flange on an inner circumference thereof, the flange being beatable in a channel formed on a wheel rim, and means to secure the flange in the channel of the wheel rim.

2. A non-inflatable tyre assembly for a vehicle as claimed in claim 1 wherein the flange and channel extend along the entire circumference of the carcass and rim respectively.

3. A non-inflatable tyre assembly for a vehicle as claimed in claim 1 or 2 wherein the flange is a lipped flange and wherein the means to secure the flange in the channel comprises a flange extending partially over the channel and over the lipped flange of the carcass.

4. A non-inflatable tyre assembly for a vehicle as claimed in claim 3 wherein the lipped flange comprises two lips projecting in opposite and outward directions and wherein the wheel rim includes two complimentary shaped flanges extending partially over the channel and over the lipped flanges of the carcass, and wherein the wheel rim comprises two components being secured to each other such that the flanges of the wheel rim operatively clamp the flanges of the carcass.

A non-inflatable tyre assembly for a vehicle as claimed any one of the preceding claims wherein the wheel rim includes peripheral flanges which include an inwardly projecting lip to locate in a groove formed on the outer surface of the carcass or wherein the peripheral flanges include a series of inwardly projecting pins which operatively penetrates the rubber carcass to hold the tyre in place over the rim.

6. A non-inflatable tyre assembly for a vehicle as claimed in any one of the preceding claims wherein the carcass includes a series of equally spaced passages extending transversely through the carcass to provide resilient waisted supporting ribs between the passages and wherein the passages are shaped as a figure eight.

A non-inflatable tyre assembly for a vehicle substantially as described herein with reference to the accompanying drawings.