EP1910104A1

EP1910104A1 - Optimized support element

Info

Publication number: EP1910104A1
Application number: EP06764206A
Authority: EP
Inventors: Jean-Charles Lacour; Sébastien RIGO; Denis Morin
Original assignee: Michelin Recherche et Technique SA Switzerland; Michelin Recherche et Technique SA France; Societe de Technologie Michelin SAS
Current assignee: Michelin Recherche et Technique SA Switzerland; Michelin Recherche et Technique SA France; Societe de Technologie Michelin SAS
Priority date: 2005-07-19
Filing date: 2006-07-19
Publication date: 2008-04-16
Also published as: FR2888778A1; US20080295942A1; CN101223044A; WO2007010003A1; JP2009501668A

Abstract

The invention relates to a support element to be mounted on a rim inside a tire on a vehicle for supporting the tread of this tire in the event of a loss in filling pressure. The support element comprises, a base, a top and an annular body in which each support wall of the annular body has a slanted parallelepiped shape with two circumferentially oriented outer faces placed on both sides of the support element and two faces that are slanted in relation to the circumferential direction of an angle a, two adjacent support walls forming a V-shaped pattern, and at the base of V, two adjacent support walls are separated by a narrow lateral slit radially extending over the entire annular body.

Description

OPTIMIZED SUPPORT SUPPORT

The present invention relates to the support supports for vehicle tires, intended to be mounted on their rims inside the tires to support the load in case of tire failure or abnormally low pressure.

WO2005 / 044598 discloses a support support intended to be mounted on a rim inside a tire fitted to a vehicle, to support the tread of the tire in case of loss of inflation pressure, comprising:

a substantially cylindrical base intended to fit around the rim,

a substantially cylindrical vertex intended to come into contact with the inner part of the tire situated under the tread in the event of loss of pressure and leaving a guard with respect thereto at the nominal operating pressure of the tire, and

an annular body connecting the base and the top, said body being constituted by a plurality of generally radial supporting partitions distributed over the circumference of the support and extending axially substantially on either side of the support, wherein the support partitions have in their central portion two axially offset segments circumferentially offset and connected by an inclined segment and are connected in pairs by connecting elements extending substantially circumferentially and interrupted by axial slots of very small width, slots designed to facilitate the buckling of the bulkheads during a chicken nest or sidewalk shock.

The invention relates to a similar support support in which the operation during a shock is further improved without degrading its running flat performance.

The support support according to the invention is characterized in that: each support partition has an oblique parallelepipedal shape with two circumferentially oriented outer faces disposed on either side of said support and two faces inclined relative to the circumferential direction of an angle α,

in that two adjacent support partitions form a V-shaped pattern, and

in that two adjacent support partitions are separated at the base of the V by an axial slot of small width extending radially over the entire annular body.

The support according to the invention has the advantage of having a behavior during a hen-type or sidewalk type shock, that is to say during a localized shock on a substantially axially oriented indenter , a behavior much more regular than the support of the document WO2005 / 044598. Indeed, when such a shock falls on the central part of a wall of the support of this document, the buckling resistance is very strong and when the impact falls on an axial slot, the resistance is much more iàible.

By small width is meant that the width in the circumferential direction separating two adjacent partitions is very significantly less than the radial height of an annular body. This ensures that when running at low pressure or at zero pressure, the partitions abut against each other.

According to a preferred embodiment, the support according to the invention is such that each support partition has a central portion in the form of an oblique parallelepiped extended by two lateral portions of rectangular trapezoidal shape with an axial face, of axial width. said shoulder face and intended to abut against a similar shoulder face of the lateral part of the circumferentially adjacent support partition, a circumferential outer face and an inclined face relative to the circumferential direction of an angle α and extending the inclined face of the central portion of said support partition.

This embodiment makes even more homogeneous the behavior of such support during a shock regardless of the azimuth of the shock. It also has the advantage of providing a contact pressure between the top of the support and the top of the tire more homogeneous during a flat run. This makes it possible to prevent the lubricants arranged in Ia cavity formed by the tire and the rim to facilitate the run flat are expelled from the pneumatic interface / top of the support run flat.

Each partition may also have at least one lateral portion extended axially by a substantially parallelepiped-shaped complementary portion with a shoulder face which extends the shoulder face of the adjacent lateral portion and a circumferential outer face of identical section. to the outer face of said adjacent side portion.

This complementary lateral part makes it possible to prevent the circumferential width of the outer faces of the partitions from becoming too low, which would deprive the lateral parts of a sufficient load bearing capacity.

Advantageously, the thickness of the central part of the partitions being e, the circumferential width of the outer faces / is such that:

3

And, the thickness of the central part of the partitions being e, the axial width of said shoulder faces L is such that:

These values make it possible to optimize the geometry of the partitions so that they have a sufficiently homogeneous response during shocks but also when running flat.

It is advantageous for the partitions to resist in a unitary manner to shocks but always in a coordinated manner during a run flat that the width (d) in the circumferential direction of the slots remains greater than two millimeters and less than 3 millimeters .

Preferably, each slot being defined geometrically by a transverse profile obtained by cutting the slot by a cutting plane substantially transverse to the mean direction of the slot, the transverse profile has at its radial ends curvatures (p) greater than one (1) mm. The fact that the slots have at their or their radial ends a transverse profile with a curvature greater than 1 mm provides excellent fatigue behavior of these ends. Indeed, it has been found that with lower curvatures, for example of the order of 0.5 mm, cracks can gradually appear when running flat at these radial ends of the slots or during repeated impacts on corners by example.

It is advantageous that these curvatures are between: d

in which d is the transverse width of the slots.

The support supports according to the invention are intended to be mounted (and disassembled) around a rim having a bearing surface by being pushed axially by a rotary mounting roller of given diameter, the wheel assembly, pneumatic and support being rotated. An example of such a mounting tool and the mounting method are described for example in the application EP 1351832 B1. To facilitate this assembly and disassembly, it is advantageous that the axial distance separating the outer faces arranged in the same plane meridian of two adjacent partitions is less than the diameter of the mounting roller. A typical mounting roller diameter value is 40 mm. When the support has openings of circumferential length greater than 40 mm, the mounting roller can enter these openings and thus fail to make a regular displacement of the support on the bearing surface of the rim.

To facilitate the production of a support according to the invention, the shape of the partitions, blocking walls and slots is advantageously adapted so as not to include any part against undercut opposed to an axial demolding of the support support.

The constituent material of a support support according to the invention may be a rubbery elastic modulus mixture of between 10 and 40 MPa. He can be also a polyurethane elastomer with a modulus of elasticity of between 20 and 150 MPa. Another preferred material is a thermoplastic elastomer with a modulus of elasticity of between 20 and 150 MPa.

According to a second embodiment of the support support according to the invention, this support is such that it comprises an additional blocking portion with a top, a base and an annular body axially extending on one side the the base, the base and the annular body of the support and such that the annular body of the locking portion comprises a plurality of locking partitions extending axially a fraction of the supporting support partitions.

Such a support support is particularly adapted to be disposed on a wheel rim so that the locking portion cooperates with the geometry of one of the seats to lock on its seat one of the beads of the tire.

According to an advantageous embodiment, the V support and blocking partitions form patterns of general shape Y.

The invention also relates to an assembly consisting of a support as previously described and a wheel with a wheel rim having a first rim seat of maximum diameter Φsim _a x, and a second rim seat of maximum diameter Φs2maχ greater than the maximum diameter of said first seat Φsimax, said second seat being extended axially towards the first seat by a circumferential groove and a bearing surface whose outer diameter is substantially equal to the maximum diameter of the first seat Φsim _a x, characterized in that said wheel comprises a rim and a disc connected to said rim on the side of said second seat.

This set has the advantage over similar sets known to offer additional gain in terms of anti-intrusiveness related to the increase of the guard between support and tire when we keep the same maximum diameter of the wheel. Other features and advantages of the invention appear from the description given hereinafter with reference to the accompanying drawings which show, by way of non-limiting examples, embodiments of the subject of the invention:

- Figure 1 is a side view of a support support;

- Figure 2 is an axial sectional view of a wheel rim and the support of Figure 1;

FIG. 3 is a section AA as indicated in FIG. 1 of a support support according to the invention;

- Figure 4, similar to Figure 3, shows a section of a variant of a support support according to the invention;

- Figure 5, similar to Figure 3, shows a section of a second variant of a support support according to the invention;

FIG. 6, similar to FIG. 3, shows a section of a second embodiment of a support support according to the invention;

- Figure 7 shows a cross section of the radial end of a slot;

- Figure 8, similar to Figure 2, presents in axial section a support according to Figure 6 mounted on a wheel;

- Figure 9 shows, in partial perspective view, a section AA of a support support similar to that shown in Figure 5; and

FIG. 10 presents a diagram comparing the forces recorded at the wheel center, as a function of the displacement, of a wheel and support support assembly according to FIG. 9 on a plane and on a representative indenter.

Figure 1 shows a side view of a support support 1 according to the invention. This support consists essentially of three parts:

a base 2, of generally annular shape;

a vertex 3, substantially annular; and

an annular body 4 connecting the base 2 and the vertex 3.

By generally or substantially annular, it is meant that the base and the top may comprise elements such as mounting wedges or carving elements (pavers, ribs, ribs) which locally make the geometry of the support n 'is not annular, while being made to fit around an annular bearing surface of the wheel.

This support 1 is intended to be mounted around a wheel 5 with a preferred rim 6 as shown in Figure 2 and inside the cavity of a tire. Such a rim is described in particular in document EP 1 206 357. This rim 6 comprises an outer seat 8 and an inner seat 9. The two seats are of unequal diameters and the seat of smaller diameter is disposed on the outer side of the rim , that is to say adjacent to the connection zone between the disc and the rim. The rim also comprises a bearing surface 10 in which the support 1 is disposed. The bearing surface comprises a circumferential groove intended to cooperate with a plurality of blocking wedges 12 of the support 1 to block the support in use. on its reach 10.

In Figure 3 is shown an annular body 20. This figure is a sectional view AA as indicated in Figure 1. The annular body 20 consists of oblique parallelepipedal partitions 21.

The partitions 21 extend laterally on either side of the circumferential mid-plane P and are regularly distributed over the circumference of the support. These partitions 21 are inclined relative to the circumferential direction by an angle α between 70 and 85 degrees depending on the axial width of the support support. Their thickness e is constant. Two adjacent partitions have an opposite inclination relative to the axial direction and form a V-shaped pattern. The partitions 21 comprise two inclined faces 23, of inclination α relative to the circumferential direction and two outer faces 24 of circumferential orientation. Two adjacent outer faces are separated from one axial side of the support by a slot 22, this slot has a circumferential distance d of between 2 and 3 mm; on the other side, two adjacent outer faces 24 are separated at most a circumferential distance D so that the support supports can be mounted around the bearing surface 10 without problems. Indeed, during this assembly, the support is pushed axially by a rotary mounting roller of given diameter. Such mounting rollers usually have a diameter of the order of 40 mm and this circumferential distance must be at most 40 mm. mm to avoid that during assembly the roller will not penetrate between two adjacent partitions and thus may damage these partitions and support. As a result, the inclination of the partitions is variable depending on the number of partitions and the axial width of the support support.

The sizing of the partitions 21 is mainly made according to the load that must bear the support and the acceptable boom to carry this load. The number of partitions also intervenes. This number plays directly on the buckling load of the partitions for a given stiffness. It is the volume of the partitions which thus determines the rigidity of crushing on a plane floor of the support.

Another test intervenes for the optimization of the geometry of the support supports. It is the crushing rigidity of the support mounted on its bearing surface against a half-cylindrical shaped indenter with a diameter of 80 mm. It has been found that such an indenter is representative of the crushing of a complete pneumatic support and wheel assembly during an impact on a transverse indenter such as a sidewalk or a pothole.

To optimize the geometry of a support support, it is sought to increase the ratio between the crush stiffness on a flat ground and the crush stiffness on this representative indentor, the latter crush rigidity being taken in the most unfavorable conditions, that is to say that one retains the maximum rigidity according to the azimuth of the support.

The support shown in Figure 3 has a K ratio substantially greater than 2.10. This support, however, has a behavior that is not regular enough depending on the azimuth.

Figure 4 shows an annular body 30 the partitions have an oblique central parallelepipedal portion 21 as previously extended on either side of the two outer faces 24 by side portions 31 of substantially rectangular trapezoidal shape. These lateral portions 31 comprise a face identical to the face 24, an outer face 34 of circumferential orientation, a face 32 of axial orientation called shoulder face and an inclined face 33 which lies in the extension of the face. 23. As previously, two adjacent partitions are separated on one axial side by a slot 35 whose circumferential distance is between 2 and 3 mm, and on the other by a circumferential distance D less than or equal to the diameter of a roller usual mounting.

The addition of the rectangular trapezoidal side portions has two main advantages. This improves the run-flat behavior by allowing good support from one pattern to the other because the shoulder faces are large enough. It also improves the regularity of the behavior under a transverse shock.

The axial distance / outer faces 34 should preferably remain such that:

3 in which e is the thickness of the partitions in their central part.

Compliance with this limit allows to give and keep the side parts an effective complementary role of carrying the load.

Likewise, the axial length L of the shoulder faces 32 must be such that:

L ≥ * e

3

This makes it possible to obtain good behavior in flat running.

The optimized annular body of Figure 4 allows the corresponding support support to significantly improve the value of the ratio K between crushing rigidities on planar ground and representative indentor. With a support mainly made with a rubbery material, it is possible to reach and exceed a factor of 2.5.

A support support which has such a high factor has the advantage, for a given dimensioning load, strongly limit the forces transmitted to the wheel center during a violent impact load capacity in flat rolling given. Figure 5 shows an annular body similar to that of Figure 4 wherein the side portions are extended by a complementary portion 41 in the form of parallelepiped. These complementary lateral parts comprise an outer face 44 of identical section to the face 34, a complementary shoulder face 42 which axially extends the face 32 and a face 43 parallel to 42 and disposed in the extension of the face 33. The interest of this complementary lateral portion 41 is to allow to respect the preceding limits for / and L in certain configurations of thickness, inclination and axial width of the partitions and the support.

[0044] A second embodiment of a support according to the invention is shown in Figures 6 and 8. These figures have a support 130 comprises a portion 132 of the load support and an additional portion 134 of the bead of the tire lock . This support 130 comprises an annular body 50. This annular body is shown in Figure 6. It consists of partitions similar to those of Figure 4 supplemented axially on one side of the support by axial partitions 51. These axial partitions 51 have a thickness substantially smaller than that of the partitions 21. Their function is to allow to connect the top to the base by providing sufficient axial rigidity to be able to cooperate with a safety boss to lock in position a tire bead and disassemble the support by pushing a mounting roller. This part of the annular body has only a marginal contribution to the carrying of the load. The patterns of the partitions of the annular body 50 thus have a general shape of Y.

FIG. 8 illustrates a second set 100 tire 102, wheel 110 and support 130 according to the invention. The wheel 110 of this set has the same as that of Figure 2 two seats of maximum diameters Φsim _a x and different. It differs from the wheel 5 of Figure 2 in that the connection area between the disk 114 and the rim 112 is disposed on the side of the seat 116 of larger diameter Φs2maχ- The tire 102 comprises a tread 104, two flanks 106 and two beads 108 of different diameters adapted to rest on the seats 116 and 118 of the rim 112. The rim 112 comprises a bearing surface 120 around which substantially rests the support portion 132 of the support 130 and between the seat 116 and the bearing surface 120, a circumferential groove 122. This circumferential groove 122 serves to accommodate the wheel valve and to allow the assembly and disassembly of the bead 108 of the tire on the seat 116. The locking portion 134 of the support 130 abuts against the flank 126 of the circumferential groove 124 to cooperate with the safety boss 128 of the seat 116 to lock in position the bead 108 of the tire 102.

Figure 7 shows an advantageous form of the transverse profile of the radial ends of the slots 35 and 45. This transverse profile is obtained by cutting the slot by a cutting plane substantially transverse to the mean direction of the slot.

In Figure 7 as in the previous figures, we see that the transverse width d of the slot is substantially constant over the entire radial height of the slot. This transverse width d is here of the order of 2 to 2.5 mm. This profile has at its radial end a bulge of width greater than d. At this end, the transverse profile has curvatures p greater than one millimeter. In the example of Figure 7, the bulge is toroidal shape with a radius of about two mm.

As the slots 35, 45 extend over the entire radial height of the annular bodies, this bulge is located at both inner and outer radial ends of the slot.

The presence of these bulges can significantly improve the rolling resistance of the support while maintaining excellent behavior during a shock on a corner for example.

Figure 9 shows a partial perspective view a section AA of a support support similar to that of Figure 5. The annular body 30 of this support comprises inclined oblique partitions 21 extended on either side by complementary parts in the form of rectangle trapezium 31. This figure also includes the base 2 of the support. This base 2 has the same axial dimension as the partitions of the annular body.

FIG. 10 illustrates the behavior of the optimized support of FIG. 9 during a flat plane crash at 80 ° C. (curve a) and on a half cylindrical indenter of FIG. diameter 80 mm at 23 ° C (curve b). The crushes are carried out the support being mounted on its service rim. The two curves a and b have a first substantially linear portion followed by a maximum which corresponds to the buckling of the partitions.

The support is sized to crash on a flat ground with an arrow / _N under its service load Q _N This design on ground plane is preferably carried out considering the support at its operating temperature in running at dish. This temperature is of the order of 80 ° C or more. When the support is crushed on the cylindrical mi indenter, for the same arrow fy it is subjected to a load Q _c . The ratio Q _N IQ _C corresponds to the ratio of the ground plane / indent rigidities. The indenter crash tests are carried out at room temperature. The ratio of the rigidities considered thus takes into account the evolution of the modulus of the material constituting the support between the ambient and operating temperatures. This significantly penalizes the values obtained from these reports.

The ratio of plane / indent rigidities here is greater than 2.5 in the case of a support made with a rubbery mixture.

This support support is thus optimized due to the fact that the areas of the walls impacted during a transverse (or axial) impact are minimal and very regular depending on the azimuth, the support has a high rigidity axial which allows excellent behavior and distance D between two adjacent partitions allows easy assembly (and disassembly).

The invention is not limited to the examples described and shown and various modifications can be made without departing from its scope only limited by the following claims.

Claims

1. Support support intended to be mounted on a rim inside a tire fitted to a vehicle, to support the tread of this tire in the event of loss of inflation pressure, comprising:

a substantially cylindrical base intended to fit around the rim,

an annular body connecting the base and the top, said body being constituted by a plurality of generally radial support partitions distributed over the circumference of said support and extending axially substantially on either side of said support, characterized in that :

each support partition has a central portion in the form of an oblique parallelepiped with two circumferentially oriented outer faces disposed on either side of said support and two faces inclined relative to the circumferential direction of an angle α,

in that two adjacent support partitions form a V-shaped pattern,

in that two adjacent support partitions are separated at the base of the V by an axial slot of small width extending radially over the entire annular body, and

in that the central portion of each oblique parallelepiped-shaped support partition is extended by two lateral portions of rectangular trapezoidal shape with an axial face, of given axial width, referred to as the shoulder face, intended to be supported against a similar shoulder face of the lateral portion of the circumferentially adjacent support partition, a circumferential outer face and a face inclined relative to the circumferential direction of an angle α and extending the inclined face of the central portion of said support partition. .

2. Support support according to claim 1, wherein each partition has at least one lateral portion extended axially by a complementary portion of substantially parallelepiped with a shoulder face which extends the shoulder face of the adjacent side portion and a circumferential outer face of identical section to the outer face of said adjacent side portion.

3. support support according to one of claims 1 and 2, wherein, the thickness of the central part of the partitions being e, the circumferential width of said outer faces / is such that:

4. support support according to one of claims 1 to 3, wherein, the thickness of the central portion of the partitions being e, the axial width of said shoulder faces L is such that:

5. support support according to one of claims 1 to 4, such that the width (d) in the circumferential direction of the slots is between two and three mm.

6. Support support according to one of claims 1 to 5, wherein, each slot being geometrically defined by a transverse profile obtained by cutting the slot by a cutting plane substantially transverse to the mean direction of the slot, the transverse profile has at its radial ends curvatures (p) greater than one (1) mm.

Support support according to claim 6, wherein the curvatures (p) are between: ^d

in which d is the transverse width of the slots.

8. Support according to one of claims 1 to 7, wherein, said support being intended to be mounted on the bearing surface of a wheel by means of a mounting roller of given diameter, the axial distance separating the outer faces disposed in the same meridian plane of two adjacent partitions is smaller than the diameter of said mounting roller.

9. Support according to one of claims 1 to 8, such as the shape of the partitions, blocking walls and slots is adapted to include no undercut portion opposing an axial release of the support Support.

10. Support according to one of claims 1 to 9, such that the material constituting said support support is a rubber mix of modulus of elasticity of between 10 and 40 MPa.

11. Support according to one of claims 1 to 9, such that the material constituting said support support is a polyurethane elastomer modulus of elasticity between 20 and 150 MPa.

12. Support according to one of claims 1 to 9, such that the material constituting said support support is a thermoplastic elastomer modulus of elasticity between 20 and 150 MPa.

Support support according to any one of claims 1 to 12, such that said support comprises an additional locking portion with a crown, a base and an annular body axially extending on one side the vertex, the base and the body annular of said support and such that the annular body of the locking portion comprises a plurality of blocking walls extending axially a fraction of the support partitions of said support.

The support of claim 13, wherein the V-shaped and blocking support partitions form patterns of general shape Y.

15. Support according to one of claims 13 and 14, intended to be threaded around a wheel rim having a first rim seat of maximum diameter Φsim _a x, and a second rim seat of maximum diameter Φs2m _a χ upper at the maximum diameter of said first seat Φsim _a x, said second seat being extended axially towards the first seat by a circumferential groove and a bearing surface whose outer diameter is substantially equal to the maximum diameter of the first seat Φsim _a x, wherein said support portion of said support is adapted to be disposed around said bearing surface and said locking portion is adapted to be disposed radially outwardly relative to said circumferential groove.

16. Support according to claim 15, wherein said second seat being extended towards the first seat by a flank of said circumferential groove, said locking portion of said support is adapted to abut against said side of said groove.

17. Support according to one of claims 15 and 16, wherein said wheel comprises a rim and a disc connected to said rim on the side of said second seat.

18. Assembly consisting of a support according to one of claims 1 to 17 and a wheel with a wheel rim having a first rim seat of maximum diameter Φsimax, and a second rim seat of maximum diameter Φs2maχ greater than the maximum diameter of said first seat Φsim _a x, said second seat being extended axially towards the first seat by a circumferential groove and a bearing surface whose outer diameter is substantially equal to the maximum diameter of the first seat Φsim _a x, characterized in that said wheel comprises a rim and a disk attached to said rim on the side of said second seat.