DE102009043219A1 - A tire having a mechanical energy supply device, a method of providing the mechanical energy by means of the tire and using the mechanical energy - Google Patents

Abstract

A tire is provided with a device for providing mechanical energy. The tire is characterized in that the device has at least two arranged on an inner side of a tread of the tire, by a joint movement against each other movable leg, wherein a distance between the legs by the joint movement is variable. According to the method, the tire is deformed during a rolling movement such that it comes to the joint movement of the legs and thereby the mechanical energy is provided. The invention is used for self-sufficient energy supply of tire control systems.

Description

The The invention relates to a tire with apparatus for providing a mechanical energy. In addition, a method for providing the mechanical energy using the tire and a use indicated the provided mechanical energy.

sensors based on MEMS (Micro Electro Mechanical Systems) technology, are increasingly being used. Particularly interesting are here Sensor nodes and networks that are energy self-sufficient. Such Systems draw the necessary for the operation of individual components electrical energy not from a mains supply or a battery, but about a suitable energy converter from the environment.

One Significant field lies in the automotive industry, for example in connection with tire control systems (tire sensors). today Monitor tire pressure monitoring systems Pressure fluctuations in the car tire by changing pressure and temperature at certain intervals measure and wireless the results send a control unit. Therefore necessary electrical components (tire electronics) are over a Valve attached to a rim of the car tire. The for the operation the tire pressure monitoring system necessary energy is from a Battery delivered. The battery limits the life of the tire pressure monitoring system.

New Concepts require that the tire pressure monitoring system stop working on the rim, but directly on the inside of the tire lash (Footprint) is placed. In this way it is possible, in addition to pressure and temperature also physical properties between car tires and road surface to measure and derived data usable for a driving dynamics close. Such an expansion of the tire control system means but shorter Measurement and transmission intervals, a higher measurement frequency and thus a much shorter one Battery life.

Furthermore it is necessary to miniaturize the tire control system, so that its mass is significantly reduced and thus a running property of the car tire is not adversely affected (for example by major imbalance).

task The present invention is, in terms of energy self-sufficient Systems provide mechanical energy necessary for a tire control system to disposal can be made.

to solution The object is a tire with a device for providing indicated a mechanical energy. The tire is characterized in that the device comprises at least two on an inner side of a tread of the Tire arranged, by a joint movement against each other movable leg has, wherein a distance between the legs by the joint movement variable is.

to solution The object is also a method for providing mechanical Energy for a piezoelectric energy converter using the tire indicated, wherein the tire deformed during a rolling motion so is that it comes to the joint movement of the thighs and thereby the mechanical energy is provided.

At Any tire is conceivable here. Preferably, the Tire a tire of a motor vehicle, such as a passenger car or a truck.

The basic idea of the invention is that when unrolling a tire on a roadway occurring deformation of a Tire (Laces formation, entry into the laces) to provide of mechanical energy. These are the movable Thighs used. These legs act as pliers. The ready Asked mechanical energy is then for conversion into electrical Energy available.

In the case of the tire of a motor vehicle, the rolling movement over the roadway leads to the formation of a tire lash. The tire is designed so that when the formation of the tire lash, that is, in the deformation of the tire, the joint movement of the legs takes place. Conversely, when the deformation of the tire is reduced, that is to say when the tire lash dissolves, a joint movement likewise occurs. In both cases, the joint movement causes the distance between the legs to change. The change of the distance or the occurring mechanical energy can now be exploited to drive an electromechanical energy converter (generator). In this way, an energy self-sufficient system is accessible, with which electrical energy can be obtained, and with their help For example, a tire control system can be operated.

The Thighs are several mm long. Preferably, a leg length is off the range of 5 mm to 50 mm us especially from the field selected from 5 mm to 20 mm. For example, the legs are 10 mm long.

Preferably the legs have a rigid material. For example the rigid material is a metal. This ensures that mechanical Energy is not lost in a deformation of the thighs. Preferably For example, the material, such as the metal, has a high modulus of elasticity on and is elastic.

According to one special embodiment is called electromechanical energy converter a piezoelectric element is used. The electromechanical Energy converter has a piezoelectric element. Under exploitation the piezoelectric effect can be obtained here electrical energy become. For example, the piezoelectric transducer is also on the inside of the tread of the tire.

Of the Energy converter, in particular the energy converter with the piezoelectric Element has lateral dimensions ranging from a few microns up to a few mm. For example, is an area of the piezoelectric element of the energy converter 10 mm × 10 mm.

Incidentally, can on the inside of the tread of the tire, a variety of devices for providing the be arranged mechanical energy. The same applies to the electromechanical Converter. So it is possible, for example, that an electromechanical Energy converter several devices for providing a mechanical Energy are assigned. The reverse case is also conceivable that a device for providing a mechanical energy more electromechanical energy converters are assigned. In any case will do it taken care of that one for The electromechanical energy converter required mechanical energy efficiently provided.

Preferably is the electrical energy for used the operation of a tire control system.

• – Mechanische Energie kann innerhalb eines Reifens robust bereitgestellt werden.
• – Die Höhe der bereitgestellten mechanischen Energie ist unabhängig von der Fahrgeschwindigkeit, mit der der Reifen bewegt wird.
• – Zum Bereitstellen der mechanischen Energie wird im Gegensatz zu anderen elektromechanischen Energiewandlern keine seismische Masse benötigt.

In summary, the invention provides the following advantages:

• - Mechanical energy can be stably provided within a tire.
• - The amount of mechanical energy provided is independent of the speed at which the tire is moved.
• - To provide the mechanical energy, unlike other electromechanical energy converters, no seismic mass is needed.

Based an embodiment and the associated Figures, the invention is described in more detail below. The figures are schematic and do not represent true to scale illustrations represents.

1 shows the basic principle of the invention.

2 shows a detail 1 ,

3 and 4 show the geometry relations and definition of parameters.

5 shows a tire from the side.

Given is a tire 1 on the inside 3 that the tread 2 facing away from the tire, a device 10 for providing a mechanical energy. The device has a multiplicity of legs which are movable relative to one another by joint movements 4 on. The thighs are rigid. They are made of a metal.

The tire is the tire of a motor vehicle. By rolling the tire on a road 12 it comes to the formation of a tire gossip 11 ( 5 ). At formation of a tire gossip 11 it comes to a joint movement over which the leg distance 41 is reduced. In the further rolling of the tire and thus the redissolution of the tire lash the leg distance is increased again. In both cases, there is a joint movement 40 the two legs to each other or away from each other.

The legs form a tong-like device. A length of the legs is several mm. The leg The leg distance (opening diameter) changes from d ₀ to d _c when entering and exiting the lug. If an elastic element with spring constant k is deflected by the change in distance Δ _d = d ₀ -d _c , a mechanical force results: F _d = Δ _d · k (1)

These Force can now mechanical work z. B. perform on a piezoceramic. The piezoceramic in turn converts the coupled mechanical Energy into an electrical energy.

r_w

Reifenradius

s_l

Latschlänge

d₀

Zangenöffnung (Schenkelabstand) im Normalzustand

d_c

Zangenöffnung (Schenkelabstand) bei Ein-/Austritt Latsch

h_d

Zangen-Schenkellänge

In the following, the achievable distance change Δ _{d is} calculated. These are the in the 3 and 4 specified parameters are the following variables:

r _w

tire radius

s _l

shuffle length

d ₀

Pliers opening (leg distance) in the normal state

_c

Pincer opening (leg distance) at entry / exit Laces

h _d

Clamp arm length

h_β = r_d·cos( β / 2 ) – h_d (4) d_c = 2·r_d·sin( β / 2 ) (5) Δ_d = Δ_d(r_w, s_t, h_d, d₀) = d₀ – d_c = d₀ – 2·r_d·sin( β / 2 ) (6) The definitions given above result in the following relationships:

h _β = r _d * cos (β / 2) -h _d (4) d _c = 2 · r _d · sin (β / 2) (5) Δ _d = Δ _d (r _w , s _t , h _d , d ₀ ) = d ₀ -d _c = d ₀ -2 · r _d · sin (β / 2) (6)

The becomes mechanical energy released by the joint movement coupled into an electromechanical energy converter (generator), to gain electrical energy from the mechanical energy. According to one embodiment the electromechanical transducer is a piezoelectric energy converter. In the piezoelectric transducer, the mechanical energy is in coupled a piezoelectrically active layer. It happens for charge separation. The charge separation is used to electrical To produce energy.

Claims (9)

Tires ( 1 ) with at least one device for providing a mechanical energy, characterized in that the device has at least two arranged on an inner side of a tread of the tire, by a joint movement against each other movable leg, wherein a distance between the legs by the joint movement is variable. The tire of claim 1, wherein the tire is a tire of a motor vehicle. The tire of claim 2, wherein the legs are a rigid one Have material. Tire according to claim 3, wherein the rigid material a metal is. A method for providing mechanical energy to an electromechanical energy converter using the tire, wherein the tire is deformed during a rolling movement such that it causes the joint movement ( 40 ) The leg comes and thereby the mechanical energy is provided. Method according to claim 5, wherein the formation of a tire slipper ( 11 ) is caused and in the formation of the tire-Latsches the joint movement takes place. Use of the method according to claim 5 or 6 provided mechanical energy for converting the mechanical Energy in an electrical energy by coupling the mechanical Energy in an electromechanical energy converter. Use according to claim 8, wherein as electromechanical Energy converter is a piezoelectric element is used. Use according to claim 7 or 8, wherein the electrical Energy for the operation of a tire control system is used.

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