Patent Application
20230311571
The present invention relates generally to a vehicle tire and, more particularly, to a non-pneumatic tire with support rings and spokes made of reinforced rubber. In a further aspect, the invention relates to a wheel comprising such a non-pneumatic tire.
The pneumatic tire has been the solution of choice for vehicular mobility for over a century and is still dominant on the tire market today. Pneumatic tires are efficient at carrying loads because all of their structure participates in carrying the load. Pneumatic tires are also desirable because they have low contact pressure, resulting in lower wear on roads due to the distribution of the load of the vehicle. Pneumatic tires also have low stiffness, which ensures a comfortable ride in a vehicle. The primary drawback to a pneumatic tire is that it requires compressed fluid (e.g., air or an inert gas). A conventional pneumatic tire is rendered useless after a complete loss of inflation pressure.
A tire designed to operate without inflation pressure may eliminate many of the problems and compromises associated with a pneumatic tire. Neither pressure maintenance nor pressure monitoring is required. Structurally supported tires such as solid tires or other elastomeric structures to date have not provided the levels of performance required from a conventional pneumatic tire. A structurally supported tire solution that delivers pneumatic tire-like performance would be a desirous improvement.
Non pneumatic tires are typically defined by their load carrying efficiency. So-called “bottom loaders” are essentially rigid structures that carry a majority of the load in the portion of the structure below the hub. “Top loaders” are designed so that all of the structure participates in carrying the load. Top loaders thus have a higher load carrying efficiency than bottom loaders, allowing a design that has less mass.
Non pneumatic tires, particularly those that are “top loaders” typically have a shear band. A shear band while allowing the tire to have higher load carrying efficiency, have the disadvantage of increased weight and decreased rolling resistance. Thus it is desired to have an improved nonpneumatic tire that omits a shearband and is useful for consumer or commercial truck applications.
The invention will be described by way of example and with reference to the accompanying drawings in which:
The outer ring structure 102 further comprises an annular support band 108 connecting to the first support ring 104a and the second support ring 104b. The support band 108 maintains the first and second support rings 104a, 104b in substantially coaxial, parallel positions. The support band 108 has a radially outer surface on which the tread is formed as a tread band 112. The tread band 112 may include tread features such as, e.g., grooves, ribs, blocks, lugs, sipes, studs, etc. The support band includes a reinforcement layer 109 having a first end 111 that is secured to the first support ring 104a and a second end 113 that is secured to the second support ring 104b. The support band distributes forces locally exerted on the tread 112 over a larger area and yields under pressure so as to contribute to formation of a contact patch between the tread 112 and the ground. The support band 108 further includes longitudinal reinforcement 105, which wrap around each end of the annular reinforcement and function to secure the ends to the respective support ring 104a,b. The support band 108 functions to transmit the load of the tire to the support rings. The support band 108 can be in the form of a rubber band with optional reinforcements, or a metal band as a leaf spring.
The non-pneumatic tire 100 further comprises an inner ring structure including a first base ring 110a on the first lateral side 106a and a second base ring 110b on the second lateral side 106b. The first and second base rings 110a, 110b are connected to the outer ring structure by a connecting structure comprising spokes 114 made of reinforced rubber strips. The spokes 114 may be divided into two sets: a first spoke 114a that is secured to the first support ring 104a and extends from the first support ring to the second base ring 110b, and is secured to the second base ring 110b, and a second spoke 114b that is secured to the second support ring 104b and extend from the second support ring to the first base ring 110a, and is secured thereto. The support rings 104a, 104b receive the load exerted on the base rings 110a, 110b as tension in the spokes 114 and transfer this load to support band 108, which, in turn, transfers the load to the ground, via the tread.
As shown in
As best shown in
As shown in
The spokes are preferably arranged such that the first spokes and second spokes cross each other in a X shaped configuration when viewed from the cross-section, and without intersecting each other. The first spokes may alternate with the second spokes in circumferential direction around the tire axis.
The first and second base rings may be axially movable one with respect to the other. Tension within the first and second spokes may be adjustable by axially moving the first and second base rings one with respect to the other.
In embodiments, the first and second spokes may have inclination angles between 10 and 60°, preferably between 15° and 50°, more preferably between 15° and 45°, with respect to the tire axis.
The tire 100 may be mounted on a rim shown in
When the first spokes extend from the first support ring to the second base ring and the second spokes extend from the second support ring to the first base ring, the first and second base rings may be secured in the first and second axial positions against tension forces in the first and second spokes tending to move the first and second base rings axially closer together. The rim may further include a clamp to secure the first base ring between the first axially inner abutment and the first axially outer abutment, and a second clamp to secure the second base ring between the second axially inner abutment and the second axially outer abutment.
The support band 208 has a radially outer surface having a tread band 212. The support band 208 includes an annular reinforcement 209 extending from the first support ring 204a to the second support ring 204b. The support band 108 further includes longitudinal reinforcement 205. The support band distributes forces locally exerted on the tread 212 over a larger area and yields under pressure so as to contribute to formation of a contact patch between the tread 212 and the ground.
The tire 200 further comprises an inner ring structure including a first base ring 210a on the first lateral side 206a and a second base ring 210b on the second lateral side 206b. The first and second base rings 210a, 210b are connected to the outer ring structure by a connecting structure comprising spokes 214 made of reinforced rubber strips. The spokes 214 include a first spoke 214a that wraps around the first support ring 204a and extends to the second base ring 210b and is secured thereto, and a second spoke 214b that extend from the second support ring 204b to the first base ring 210a (the “second spokes” in this embodiment).
The first and second spokes 214a, 214b extend generally linearly and are inclined with respect to the tire axis. The spokes are arranged in an X-shaped configuration when viewed from the cross-section. The spokes of the first and second sets cross each other in a plane perpendicular to the tire axis located centrally between the support rings and the base rings.
Unlike in the embodiment of
Referring to
The support band 308 has a radially outer surface on which the tread is formed as a tread band 312. The tread band 312 may include tread features such as, e.g., grooves, ribs, blocks, lugs, sipes, studs, etc. The support band 308 includes a plurality of reinforcements 309 extending from the first support ring 304a to the second support ring 304b. The support band further includes one or more cushions 307 arranged between the reinforcement 309 and the tread band 312. The cushions 307 distribute forces locally exerted on the tread 312 over a larger area and yield under pressure so as to contribute to formation of a contact patch between the tread 312 and the ground. The optional cushions are formed of foam or sponge rubber. The support band 308 further includes longitudinal reinforcement 305.
The tire 300 further comprises an inner ring structure including a first base ring 310a on the first side 306a and a second base ring 310b on the second side 306b. The first and second spokes 314a, 314b extend generally linearly and are inclined with respect to the tire axis. The spokes are arranged in an X-shaped configuration. The first and second spokes cross each other in a plane perpendicular to the tire axis located centrally between the support rings and the base rings.
Each first spoke 314a is connected with the first support ring 304a and with the second base ring 310b. Each second spoke 314b is connected with the second support ring 304b and with the first base ring 310a. As shown in
The rim drum 324 comprises a first and a second series of openings 331 along first and the second flange. Each of these openings 331 is configured to accommodate the nut base 332 of a clamping jaw. The nut base 332 comprises an inside threaded hole 334 that is perpendicular to the insertion direction of the nut base 332. When the nut base 332 is in place, the inside threaded hole 334 is in alignment with an axially oriented bore 336 in the rim drum 324. The first and second flanges comprise corresponding bores 338 that are aligned with the bores 336 in the rim drum. The first and second base rings are clamped between the respective clamping jaws and flange with bolts 340.
The axial extents of the openings 331 are somewhat greater than the axial extents of the base nuts 332. When the bolts 340 are fastened, the clamping jaws 330a, 330b are moved axially outwards, pushing the first and second base rings 310a, 310b to axially more outward positions. This leads to pretension of the spokes 314.
In the illustrated embodiment, both flanges 328a and 328b are removable. The tire may be slid on the rim 322 when the flanges 328a, 328b and the clamping jaws 330a, 330b are removed. When the tire is in place, the flanges and the clamping jaws are mounted and bolted.
The support band has a radially outer surface formed by a tread band 412. The support band includes reinforcement 409 extending between the first and second support rings 404a, 404b. The support band further includes one or more cushions 407 arranged between the reinforcement 409 and the tread band 412. The cushions 407 distribute forces locally exerted on the tread 412 over a larger area and yield under pressure so as to contribute to formation of a contact patch between the tread 412 and the ground. The support band further includes longitudinal reinforcement 405.
The non-pneumatic tire 400 further comprises an inner ring structure including a first base ring 410a on the first lateral side 406a and a second base ring 410b on the second lateral side 406b. The first and second base rings 410a, 410b are connected to the outer ring structure by a connecting structure comprising spokes 414 made of reinforced rubber. The spokes 414 can be divided in two sets:
The spokes 414 of the first and second sets are slanted with respect to the tire axis. The spokes 414 are arranged in a V-shaped configuration. In the illustrated embodiment, in circumferential direction around the tire axis, the spokes of the first set alternate with the spokes of the second set. However, since the spokes do not cross, the first and second spokes could also pairwise be arranged axially facing each other. In the illustrated embodiment, there are 36 spokes 414 in total, including 18 first spokes 414a and 18 second spokes 414b. The spokes are uniformly distributed in circumferential direction and the angular separation α between two neighboring first spokes 414a or between two neighboring second spokes 414b amounts to 20°.
As in the embodiment of
The rim drum 424 comprises a series of axially oriented inside threaded holes 431 distributed along the lateral circumferential edges of the rim drum 424. The first and second flanges 428a, 428b comprise corresponding bores 438 that are aligned with the threaded holes 431 in the rim drum, such that the first and second flanges 428a, 428b may be fixed on the rim drum 424 by bolts 340.
The first and second base rings are clamped between the respective clamping jaws and flange with bolts 340.
In the illustrated embodiment, both flanges 428a and 428b are removable. The tire may be slid on the rim 422 when at least one of the flanges 428a, 428b is removed. The median rim ring 429 is arranged between the base rings 410a, 410b before the tire is placed on the rim drum 424. The base rings 410a, 410b and the median rim ring 429 are then slid into abutment with one of the flanges 428a or 428b. Finally, the other flange is mounted, in such a way that the base rings 410a, 410b and the median rim ring 429 are clamped between the flanges 428a, 428b.
In any of the above-described embodiments, the cores of the support and base rings could be made from metal, e.g., steel, aluminum, etc., from reinforced rubber, from plastic, or from a composite material (e.g., reinforced rubber, fiber-reinforced plastic, etc.) The reinforcement of the rubber spokes, the support bands, etc. may be made of steel cords and/or cords formed from nylon fiber, polyester fiber, fiber glass, carbon fiber, aramid fiber, glass fiber, polyethylene fiber, polyethylene terephthalate fiber, or other reinforcement materials. Different reinforcement materials could be combined. It is worthwhile noting that a “cord” may include one or plural strands. The configuration of the tire structure, in particular the base rings, the spokes, the support rings and the support band, as well as the choice of materials may depend on the envisaged use of the tire and, in particular, the intended load-bearing capability.
Variations in the present invention are possible in light of the description of it provided herein. While certain representative embodiments and details have been shown for the purpose of illustrating the subject invention, it will be apparent to those skilled in this art that various changes and modifications can be made therein without departing from the scope of the subject invention. It is, therefore, to be understood that changes can be made in the particular embodiments described which will be within the full intended scope of the invention as defined by the following appended claims.
