Pneumatic tire comprising a device for measuring a mechanical force and use of the device

Abstract

The invention relates to a tire comprising an apparatus, wherein the apparatus comprises a first, second, third, fourth and fifth layer, the third layer being optional, characterized in that: a) the first layer comprises a first electrode material, b) the second layer comprises a first intermediate material, c) the third layer comprises an insulation material, d) the fourth layer comprises a second intermediate material, and e) the fifth layer comprises a second electrode material, wherein the second or fourth layer has a layer thickness in the range from 10 to 1000 μm, the first intermediate material of the second layer and the second intermediate material of the fourth layer are different, and the four or five layers are arranged one above the other according to the above sequence. The invention also relates to uses of the apparatus.

Claims

1. A tire comprising: a tire tread and; an apparatus mounted in the tire tread for measuring mechanical forces of the tire during travel without additional electrical power, the apparatus comprising: a first layer, a second layer, a third layer, a fourth layer and a fifth layer, wherein: a) the first layer comprises a first electrode material; b) the second layer comprises a first intermediate material; d) the fourth layer comprises a second intermediate material and the third layer is between the second layer and the fourth layer and comprises an insulative material; and, e) the fifth layer comprises a second electrode material; the second or the fourth layer has a layer thickness in the range from 10 to 1000 μm; the first intermediate material of the second layer and the second intermediate material of the fourth layer are different, the layers and are arranged in order one on the other of the first layer, the second layer, the optional third layer, the fourth layer and the fifth layer, and wherein at least one of the second and the fourth layer further comprises at least one filler; the fourth layer is above the fifth layer, the second layer is above the fourth layer and the first layer is above the second layer; the first intermediate material is a terpolymer of epichlorohydrin, ethylene oxide and allyl-glycidyl ether; the second intermediate material is polydimethylsiloxane; the first and fifth layers configured to generate a voltage between them based on a mechanical force applied to the tire; a voltmeter for measuring the voltage; and a power storage charged by the voltage; a transmitter to generate a radio frequency (RF) signal from the voltage; and a control unit to evaluate the signal and determine a height of the voltage from the RF signal, the control unit mounted external from the apparatus and the tire.

2. The tire according to claim 1, further comprising an accumulator attached to a wheel and charged by the voltage.

3. The tire according to claim 1, wherein the second and the fourth layer have a layer thickness in the range from 10 μm to 1000 μm.

4. The tire according to claim 1, wherein the second and the fourth layer comprises at least one additional filler material.

5. The tire according to claim 4, wherein the at least one additional filler is a carbon black and a silica, wherein the silica of the second layer, is incorporated in an amount in the range of 0.1% to 50% by weight as a proportion of the total mass of the first layer.

6. The tire according to claim 4, wherein the at least one additional filler is incorporated in an amount in the range from 0.1% by weight to 50% by weight based on the total mass of the first and/or fifth layer of the apparatus.

7. The tire according to claim 1, wherein the first intermediate material of the second layer has a dielectric conductivity ε.sub.r of greater than 10 F.Math.m.sup.−1 and the second intermediate material of the fourth layer has a dielectric conductivity ε.sub.r of greater than 10 F.Math.m.sup.−1.

8. The tire according to claim 7, wherein a difference between specific triboelectric affinity of the first intermediate material of the second layer and specific triboelectric affinity of the second intermediate material of the fourth layer is at least 20 nC/J, measured at 20° C. and at 35% relative humidity.

9. The tire according to claim 1, wherein the third layer has a specific electrical conductivity of less than 10.sup.−1 S.Math.cm.sup.−1 at 20° C.

10. The tire according to claim 1, wherein the third layer comprises a support border formed of a vulcanized rubber or a thermosetting plastic, wherein a mixture is present in the support border, the mixture comprising one or more gases and/or particles of an insulating material, wherein the support border has a thickness of up to 200 μm and an electrical conductivity of up to 10 μS/m, or—as an insulating material, a liquid with a viscosity at 20° C. in the range from 0.1 mPa.Math.s to 10.sup.6 mPa.Math.s as measured using a rotary viscometer in accordance with DIN EN ISO 3219.

11. The tire according to claim 1, wherein a central axis of the apparatus extends in a radial direction and runs in a direction of rotation of the tire.

12. The tire according to claim 1, wherein the apparatus generates an electrical voltage and measures a mechanical force along the direction of rotation or the axial direction of the tire.

13. The tire according to claim 1, the apparatus comprising a first state where the second and fourth layers are separated, a second state where the second and fourth layers are in contact, a third state to keep electrons transferred in the second state separate and generate the voltage.

14. The tire according to claim 1, wherein a central axis of the apparatus extends in an axial direction.

Description

DESCRIPTION OF FIGURES

(1) FIG. 1 Cross section through a schematic apparatus according to the invention in a first state before application of a mechanical force, with the plane of intersection of the cross section running parallel to the central axis of the apparatus;

(2) FIG. 2 Cross section through a schematic apparatus according to the invention in a second state during application of a mechanical force, with the plane of intersection of the cross section running parallel to the central axis of the apparatus;

(3) FIG. 3 Cross section through a schematic apparatus according to the invention in a third state after application of a mechanical force, with the plane of intersection of the cross section running parallel to the central axis of the apparatus;

(4) FIG. 4 Cross section through a schematic tire according to the invention, with the plane of intersection of the cross section running at right angles to the axial direction of the tire;

(5) FIG. 5 a schematic representation of a measuring device for determining the electrical power of an apparatus according to the invention.

(6) FIG. 1 shows a schematic diagram of an apparatus 6 according to the invention, comprising five layers 1, 2, 3, 4, 5, a voltmeter 13 and a stabilization shell 7 in one embodiment. FIG. 1 shows a cross-sectional view of the apparatus 6 according to the invention, with the plane of intersection of the cross section running parallel to the central axis 19 of the apparatus 6. The central axis 19 of the apparatus 6 runs parallel to the transverse extent 18 of the various layers and through the geometric center 23 of the third layer 3 of an apparatus 6 according to the invention, and at right angles to the longitudinal extent 17 of the various layers (only the longitudinal extent 17 of the first layer 1 is shown in FIG. 1). FIG. 1 also shows the longitudinal faces 20 of the fourth layer 4 and the longitudinal faces 21 of the fifth layer 5 in schematic form in cross section. In addition, FIG. 1 shows, in schematic form, that the third layer 3, as described above, comprises a compressible compound 9 having a compression modulus and as an example of an insulation material. The apparatus 6 shown in FIG. 1 is in a first state, with no external mechanical force acting on the apparatus 6 according to the invention. In this first state, the third layer 3 separates the second layer 2 from the fourth layer 4. Since there is no contact between the second layer 2 and the fourth layer 4 in the first state of the apparatus 6 according to the invention, no electrons can be transferred between the second layer 2 and the fourth layer 4.

(7) FIG. 2 shows a schematic diagram of an apparatus 6 according to the invention, comprising five layers 1, 2, 3, 4, 5, a voltmeter 13 and a stabilization shell 7 in a further embodiment. FIG. 2 shows a cross-sectional view of the apparatus 6 according to the invention, with the plane of intersection of the cross section running parallel to the central axis 19 of the apparatus 6. The central axis 19 of the apparatus 6 runs parallel to the transverse extent of the five layers 1, 2, 3, 4, 5 and at right angles to the longitudinal extent 17 of the five layers 1, 2, 3, 4, 5, and through the geometric center 23 of the third layer 3 of an apparatus 6 according to the invention. FIG. 2 shows, in schematic form, that the third layer 3 is compressed, since a mechanical force 12 is acting on the apparatus 6 according to the invention. The apparatus 6 shown in FIG. 2 is therefore in the second state, which follows on from the first state in the time sequence, with the mechanical force 12 acting on the apparatus 6 according to the invention from above and below in the example shown in FIG. 2. In this second state, the second layer 2 and the fourth layer 4 are in contact with one another. The contact between the second layer 2 and the fourth layer 4 in the second state of the apparatus 6 according to the invention enables transfer of electrons 11 from the second layer 2 to the fourth layer 4, and hence enrichment of the fourth layer 4 with additional negative charges 11 in the form of transferred electrons. This does not yet enable the development of an electrical voltage between the first and fifth layers, and this only occurs on removal of the second layer 2 and the fourth layer 4 from one another.

(8) FIG. 3 shows a schematic diagram of an apparatus 6 according to the invention, comprising five layers 1, 2, 3, 4, 5, a voltmeter 13 and a stabilization shell 7 in a further embodiment. FIG. 3 shows a cross-sectional view of the apparatus 6 according to the invention, with the plane of intersection of the cross section running parallel to the central axis 23 of the apparatus 6. The central axis 23 of the apparatus 6 runs parallel to the transverse extent of the five layers 1, 2, 3, 4, 5 and at right angles to the longitudinal extent of the five layers 1, 2, 3, 4, 5, and through the geometric center 23 of the third layer 3 of an apparatus 6 according to the invention. FIG. 3 also shows, in schematic form, the longitudinal faces 22 of the third layer 3. In addition, FIG. 3 shows, in schematic form, in cross section, that the third layer 3 comprises a compressible compound 9 having a compression modulus as described above. The apparatus 6 shown in FIG. 3 is in a third state which differs from the first state of an apparatus 6 according to the invention merely in that the distribution of the electrons between the first, second, fourth and fifth layers 1, 2, 4, 5 is different compared to the first state.

(9) In this third state, the third layer 3 separates the second layer 2 from the fourth layer 4, with the second layer 2 comprising fewer electrons, i.e. lacking negative charges 10, compared to the first state of the apparatus 6 according to the invention. The fourth layer 4 then additionally comprises the transferred electrons 11 compared to the first state of the apparatus 6 according to the invention. In order to compensate for this electrical charge differential, electrons can then flow from the fifth layer 5 into the first layer 1. The further the second layer 2 and the fourth layer 4 are removed from one another, the higher the voltage between the fifth layer 5 and the first layer 1. The distribution of charge between the fourth layer 4 and the second layer 2 remains the same in terms of magnitude.

(10) This flow of the electrons is reversed as soon as the fourth layer 4 and the second layer 2 approach one another again until they touch, i.e. go back into the second state as shown in FIG. 2. The apparatus 6 according to the invention can thus then be converted from the second to the third state or from the third to the second state as often as desired by applying a mechanical force, and hence the electrons, as described above, can be shifted in an ever-alternating manner from the fifth layer 5 into the first layer 1 and vice versa.

(11) FIG. 4 shows a schematic diagram of a tire 24 according to the invention, comprising three apparatuses 6 according to the invention for measuring a mechanical force in a further embodiment in cross-sectional view, with the plane of intersection of the cross section running at right angles to the axis of rotation 14 of the tire 24. The three apparatuses 6 according to the invention are arranged in the tread 25 or on the inner liner 28 of the tire 24 according to the invention, with the central axis 19 of one apparatus 6 according to the invention running parallel to the circumferential direction 15 or parallel to the radial direction 16 of the tire 24 according to the invention. According to the direction in which the central axis 19 of an apparatus 6 according to the invention runs in the tread 25 of a tire 24 according to the invention, it is possible in a particularly efficient manner to measure those mechanical forces that run parallel to the central axis 19 of the apparatus 6 according to the invention. Thus, if the central axis 19 of the apparatus 6 according to the invention runs parallel to the circumferential direction 15, it is possible in an especially efficient manner to measure the braking and acceleration forces while driving with a tire 6 according to the invention. If the central axis 19 of the apparatus 6 according to the invention runs parallel to the axis of rotation 14, it is possible in an especially efficient manner to measure the lateral forces that arrive when cornering with a tire 6 according to the invention. If the central axis 19 of an apparatus 6 according to the invention runs parallel to the radial direction 16 of the tire 6 according to the invention in the tread 25, there are particularly strong mechanical forces acting on the apparatus 6 according to the invention whenever the apparatus 6 according to the invention is in the part of the tread 25 that constitutes what is called the footprint of the tire 6 according to the invention.

(12) FIG. 5 shows a schematic representation of a measuring device 29 for determining the performance of an apparatus 1 according to the invention in a further embodiment, wherein the measuring device comprises an apparatus according to the invention 1, a flywheel 30 with a piston 31, and a stabilization shell 7 with a polycarbonate stamp 34 and a polycarbonate base 35. The stabilization shell 7 also comprises a polycarbonate border 38 with holes. The holes in the border 38 are used to allow a smooth escape and filling of the interior of the border 38 with air during the rotation of the flywheel 30. The rotation of the flywheel 30 causes the upper part 32 of the measuring device 29 to be moved up and down with the stamp 34 and the first and second layers 1, 2. Unless otherwise stated, the rotation took place at a frequency of 5 Hz, i.e. 5 revolutions per second. An oscilloscope 39 connected to the first and second electrode layer 1, 5, i.e. to the first and fifth layers 1, 5 of the apparatus 6 according to the invention, was used to determine the no-load voltage between the first and second electrode layer 1, 5 via the formula V.sub.0=V.sub.L/(R.sub.S+R.sub.L) and the associated no-load current. The circuit of the oscilloscope 39 is shown schematically in FIG. 5 with the voltage source V.sub.L and the resistors R.sub.S and R.sub.L, wherein the contacts to the indicated electrical circuit are connected to the first layer 1 and to the fifth layer 5 of the apparatus 1 according to the invention.

EXPERIMENTAL EXAMPLES

(13) Test Methods

(14) 1. Surface roughness R.sub.a

(15) The results were ascertained in accordance with the

(16) DIN EN ISO 4288:1998 method.

(17) 2. Electrical measurement in open-circuit conditions

(18) The values for the open-circuit voltage and the no-load current were measured using the oscilloscope “Rigol Oscilloscope DS 4014” using the measuring device shown in FIG. 5 with a rotation frequency of the flywheel of 5 Hz. The diameter of the flywheel was 4 cm and the maximum distance between the second and fourth layers during rotation was 2.5 cm and the minimum distance was 0 cm. The oscilloscope had the following settings: Attenuation ratio: 10:1 Input resistance: 10 MΩ±2% Input capacitance: 13 pF±3 pF Maximum input CAT II 300 VAC Compensation range: 6 pF-24 pF.

(19) By the rotation of the flywheel, the second and fourth layers were periodically pressed against one another and removed from one another again. Thus, measurable voltages between the electrodes, i.e. between the first and fifth layers, are measured and from these corresponding current flows for the no-load or open circuit condition are determined, also called no-load current flows. These measurable no-load voltages and the resulting no-load current strengths were recorded by the oscilloscope in the form of periodic peaks, the period of the peaks corresponding to the frequency of rotation of the flywheel. The values recorded in Tables 2 to 4 for the open-circuit voltage and the open-circuit current level correspond in each case to the value of the difference between the maximum and the minimum of the measured peaks. Corresponding tests in which an apparatus according to the invention was used without a third layer as described above, i.e. in which the second and fourth layers were continuously touching one another and only the force acting on the second and fourth layers was changed, produced the same trends as the test results shown below.

(20) Production:

(21) TABLE-US-00001 TABLE 1 Compositions of the second and fourth layers used in the apparatus according to the invention: 2nd 3rd 4th material quantity layer layer layer GECO phr — — 100  PDMS phr 100 — — Filler phr — — see Table 2 ZnO phr — — 3 Stearic acid phr — — 2 TMTD phr — —   2.5 MBTS phr — — 1 Dicumyl phr    0.2 — — Peroxide Sulfur phr — — 1 Air % by — 100 — wt. *GECO = terpolymer of epichlorohydrin, ethylene oxide and allyl-glycidyl ether; ** PDMS = polydimethylsiloxane

(22) The second layer of PDMS and the fourth layer of GECO are produced according to a standard prior-art production process, which included the steps of mixing, rolling and vulcanizing the respective rubber mixture according to Table 1 for the second and fourth layers. The mixing of the respective rubber mixture was carried out after adding the components into a Banbury mixer at 70° C. with a rotor speed of 60 rpm for 8 minutes. The rolling was carried out with a two-roll mill for 10 minutes, so that a layer thickness of 120 μm was obtained in the finished vulcanized layer (with the exception of the fourth layer in the E7 and E8 experiments in Table 4). The vulcanization was performed in a rectangular vulcanizing mold at the standard temperatures of 120° C. for 10 minutes. The layers produced in this way had a length of 100 mm and a height of 30 mm.

(23) For the roughened surfaces of the fourth layers of examples E5 and E6, a mold segment of the vulcanizing mold which was roughened by sandblasting was used in their vulcanization. The sandblasting on the corresponding mold segment is carried out in such a way that surface roughnesses R.sub.a of 5 μm according to method DIN EN ISO 4288:1998 were achieved on the side facing the third layer.

(24) Measurement Results:

(25) Filler Content:

(26) TABLE-US-00002 TABLE 2 Experimental data for the apparatus according to the invention with varying filler components: Exp. Exp. Exp. Exp. Exp. Property Units V0 E1 E2 E3 E4 Materials used in the layers of an apparatus according to the invention 1st layer Copper Copper Copper Copper Copper 2nd layer PDMS PDMS PDMS PDMS PDMS 3rd layer Air Air Air Air Air 4th layer GECO GECO GECO GECO GECO 5th layer Copper Copper Copper Copper Copper Thickness/ μm 120 120 120  120 120  transverse extent of the 2nd and 4th layer Filler type in — Silica.sup.1 Silica.sup.1 Carbon Carbon the 4th layer black.sup.2 black.sup.2 (GECO) Filler weight in phr  0  10 40  5 15 the 4th layer as a percentage of the total weight of the fourth layer Results No-load voltage V 125 185 63 153 97 measured from peak-to-peak No-load current μA  11  24  9  18 20 measured from peak-to-peak .sup.1Ultrasil 7000GR, Surface area - 175 m.sup.2/g .sup.2Conductive Carbon Black (CCB), Printex XE2, Particle size, <30 nm, surface area 950 m.sup.2/g

(27) Table 2 shows that optimal performances can be achieved with filler contents from 5 to 40 phr. This shows that proportions from 0.1% by weight to 50% by weight, as a proportion of the total mass of the second intermediate layer (i.e. the fourth layer) of an apparatus according to the invention, performs well. Particularly high performances were achieved in the range from 1% by weight to 10% by weight (cf. experiments E0 without filler, E1 with 10-phr silica and E3 with 5-phr carbon black).

(28) Surface Roughness R.sub.a:

(29) TABLE-US-00003 TABLE 3 Experimental data for the apparatus according to the invention with varying surface roughnesses Exp. Exp. Exp. Exp. Exp. Property Units V0 E1 E5 E3 E6 Materials used in the layers of an apparatus according to the invention 1st layer Copper Copper Copper Copper Copper 2nd layer PDMS PDMS PDMS PDMS PDMS 3rd layer Air Air Air Air Air 4th layer GECO GECO GECO GECO GECO 5th layer Copper Copper Copper Copper Copper Filler type in — Silica.sup.1 Silica.sup.1 Carbon Carbon the 4th layer black.sup.2 black.sup.2 (GECO) Thickness/ μm 120 120 120 120 120 transverse extent of the 2nd and 4th layer Filler weight phr 0 10 10 5 5 in the 4th layer as a percentage of the total weight of GECO Surface μm 0.3 0.3 3 0.3 3 roughness R.sub.a of the 4th layer Results No-load V 125 185 181 153 237 voltage measured from peak-to-peak No-load μA 11 24 35 18 38 current measured from peak-to-peak .sup.1Ultrasil 7000GR, Surface area - 175 m.sup.2/g .sup.2Conductive Carbon Black (CCB), Printex XE2, Particle size, <30 nm, surface area 950 m.sup.2/g

(30) Table 3 shows that optimal performances can be achieved with surface roughnesses R.sub.a in the range from 0.1 to 5 μm. This also applies to the surface roughnesses R.sub.a of the second layer and to the range from 5 μm to 100 μm, in particular as shown in Table 3 for the range from 0.3 to 3 μm.

(31) Layer Thicknesses of the Fourth Layer

(32) TABLE-US-00004 TABLE 4 Experimental data of the apparatus according to the invention with varying thickness of the second layer Exp. Exp. Exp. Property Units V0 E7 E8 Materials used in the layers of the apparatus 1st layer Copper Copper Copper 2nd layer PDMS PDMS PDMS 3rd layer Air Air Air 4th layer GECO GECO GECO 5th layer Copper Copper Copper Filler type in the 4th layer — — — Thickness/transverse μm 120 60 250 extent of the 2nd layer Thickness/transverse μm 120 120 120 extent of the 4th layer Results No-load voltage measured V 125 61 63 from peak-to-peak No-load current measured μA 11 5 5 from peak-to-peak

(33) Table 4 shows that optimal performance can be achieved with layer thicknesses in the range from 60 to 250 μm, especially with a layer thickness of 120 μm. This also applies to the layer thickness of the fourth layer. The layer thickness corresponds to the transverse extent of a layer of an apparatus according to the invention.

LIST OF REFERENCE SIGNS

(34) 1 first layer 2 second layer 3 third layer 4 fourth layer 5 fifth layer 6 apparatus 7 stabilization shell 8 contacts between the electrode materials and the means of measuring the voltage 9 insulation material; compressible compound 10 lack of negative charges 11 additional negative charges; transmitted electrons 12 mechanical force 13 means of measuring the voltage between the first and fifth layers of the apparatus; voltmeter 14 axis of rotation; axial direction 15 circumferential direction 16 radial direction 17 longitudinal extent 18 transverse extent 19 central axis of the apparatus 20 longitudinal faces of the fourth layer 21 longitudinal faces of the fifth layer 22 longitudinal faces of the third layer 23 geometric center of the third layer 24 tire 25 tread 26 belt 27 carcass 28 inner liner 29 measuring device for determining the performance of an apparatus according to the invention 30 flywheel for upward and downward movement of the first layer (i.e. copper electrode) and second layer (i.e. first intermediate layer) of the apparatus according to the invention 31 piston for connecting the flywheel to the upper part of the measuring device 32 top part of the measuring device comprising the first and second layer of the apparatus according to the invention 33 bottom part of the measuring device comprising the fourth and fifth layer of the apparatus according to the invention 34 polycarbonate stamp 35 polycarbonate base for fastening the fourth and fifth layer of the apparatus according to the invention 36 distance between the surfaces of the first and second layer 37 diameter of the flywheel 38 polycarbonate border with holes for escape and filling the interior of the border with air 39 oscilloscope