WO2008061770A1

WO2008061770A1 - Device for measuring the tread depth of motor vehicle tyres

Info

Publication number: WO2008061770A1
Application number: PCT/EP2007/010157
Authority: WO
Inventors: Konstantinos Tsiberidis
Original assignee: Kt Projektentwicklungs Gmbh
Priority date: 2006-11-22
Filing date: 2007-11-22
Publication date: 2008-05-29
Also published as: DE102006055059A1

Abstract

The invention relates to a device for measuring the tread depth of motor vehicle tyres, said device comprising at least one sensor unit for detecting the tread depth of a motor vehicle tyre. According to the invention, in a motor vehicle (1), especially a landcraft, aircraft and watercraft, at least one sensor unit (3) for detecting the tread depth of the motor vehicle tyre (2) and/or the arrangement thereof is associated with each motor vehicle tyre (2).

Description

Device for measuring the tread depth of motor vehicle tires

The invention relates to a device for measuring the tread depth of motor vehicle tires with at least one sensor unit for detecting the tread depth of a motor vehicle tire.

Nowadays, almost all motor vehicles use gas-filled motor vehicle tires which are equipped with different profiles. For different weather conditions there are motor vehicle tires with different profiles. In all profiles, however, a sufficient tread depth must be present, as this decides on the adhesion of the tires in different weather conditions, such as rain, snow, black ice, sand or off-road driving. If the tread is too worn or if the tread depth is too low, the vehicle tire will more easily lose traction, so that accidents involving property and personal injury may occur.

Many devices and methods for determining the tread depth of a motor vehicle tire are known from the prior art.

For example, DE 4316984 A1 describes a method and a device for automatically determining the tread depth of motor vehicle tires. In this case, a measuring station is arranged in the bottom of a partially transparent measuring plate. Below the measuring plate is a measuring head, which has a laser and an image-resolving sensor as a triangulation unit. To measure the tread depth of a motor vehicle tire, the measuring plate is rolled over by the tire or the tire is parked on the measuring plate. The laser then creates a spot of light on the tread surface of the tire. The position of the light spot is observed by the sensor, the output signals of the sensor being transferred to an evaluation unit which determines the extent of the tire profile. The measuring head is arranged on a carriage and movable transversely to the rolling direction of the tire.

Furthermore, DE 19705047 A1 discloses a device in which the motor vehicle tire whose profile depth is to be measured can be turned off on a device which has two rollers through which the motor vehicle tire is rotated during the measurement. In this prior art, it is contrary to Although the device according to DE 4316984 Al possible to determine with her the tread depth during rotation of the motor vehicle tire and thus over the entire tread of the motor vehicle tire. However, this device also represents its own test stand on which the vehicle must be placed to determine the tread depth of the motor vehicle tire.

In contrast, the invention has for its object to provide a device for measuring the tread depth of motor vehicle tires according to the preamble of claim 1, wherein a continuous measurement of the tread depths of the vehicle tires during operation of the motor vehicle is possible and thus independent of a test bench.

This object is achieved by a device having the features of claim 1. Advantageous embodiments of the invention can be found in the UnteranSprüchen.

Since at least one sensor unit for detecting the tread depth of the motor vehicle tire is assigned to each motor vehicle tire in a motor vehicle, the measurement and control of the tread depth of the motor vehicle tire of the motor vehicle is independent of a separate test bench. To control the tread depth, it is no longer necessary according to the invention to go to a separate test stand. The determination of the tread depth of the motor vehicle tires can be carried out continuously during operation at predetermined time intervals during operation or else triggered manually by the driver of the motor vehicle during operation of the motor vehicle.

To measure the tread depth of the motor vehicle tire different, in particular optical distance measurements can be used to determine the distance between the sensor unit and the tread or the profile of the motor vehicle tire. Triangulation, interferometry, phase modulation and transit time measurement are particularly suitable for this purpose. Since these measuring methods are generally known methods, a detailed description of the distance determination by these methods is omitted here.

According to a first advantageous embodiment of the invention, each sensor unit has at least one sensor. By this measure, each sensor unit is associated with a sensor, with which the profile depth of the respective sensor unit assigned motor vehicle tire can be determined. By using a sensor for each sensor unit, it is possible to make the sensor unit compact, that is to say small-sized, so that it can be disposed inconspicuously on the motor vehicle.

Of course, it is also possible to provide each sensor unit with two or more sensors. In this case, each sensor can be assigned a specific region of the tread transversely to the rolling direction of the motor vehicle tire. The respective sensor then determines the tread depth of the motor vehicle tire in this tread area over the entire circumference of the motor vehicle tire. Of course, it is also possible that each sensor scans the entire tread over the entire circumference of the motor vehicle tire and supplies the data for the determination of the tread depth over the entire transverse extent of the tread of the motor vehicle tire. In this case, two or more sensors serve as redundancy for the possibility that a sensor for detecting the tread depth fails.

Furthermore, it has proved to be useful to assign each sensor unit to a transmission unit, which forward the data determined by the sensor unit to a central or higher-order processor unit arranged in the motor vehicle. The transmission unit can be designed as a radio transmitter and possibly also as a radio receiver, which communicates wirelessly with the central or higher-level processor unit. By means of the processor unit, the data detected by the sensor unit and forwarded by the transmission unit are further processed by means of a corresponding software program into the profile depths of the individual motor vehicle tires that are correlated to the data.

The sensor units can be designed such that they continuously determine the data for calculating the tread depths of the individual motor vehicle tires. Alternatively, the sensor units can of course also determine the data for calculating the tread depth of the motor vehicle tires at predetermined time intervals. It is also possible that the sensor units determine the data for calculating the tread depth of the motor vehicle tires only on the instruction of an operator or the driver of the motor vehicle. For this purpose, it is of course necessary that an operating element for starting a measuring operation is provided for the operator or the driver of the motor vehicle, preferably in the passenger compartment. Thus, the acquisition of data for calculating the tread depth of the vehicle tires can be done in a simple manner, it has proven to be advantageous to arrange the sensor units in the wheel arches or in the mudguards of the respective vehicle tires whose tread depth is to be determined. By this measure, the 5 sensors are arranged in close proximity to the motor vehicle tire, so that the methods for distance measurement can be applied in a simple manner.

In order to further increase the redundancy of the entire acquisition of the data, it is provided that at least three sensor units should be assigned to each motor vehicle tire.

According to a further advantageous embodiment of the invention, the sensor consists of a transmitter and a receiver for electromagnetic waves. These may in particular be electromagnetic waves in the visible or invisible range, preferably laser beams. Such electromagnetic radiation is particularly well suited for distance measurement with the already mentioned methods.

Alternatively, it is of course also possible that the sensor consists of a transmitter and a 2o nem receiver for pressure waves, in particular a transmitter and a receiver for ultrasonic waves. Such ultrasonic waves are also suitable for use in the already mentioned methods.

According to a particularly advantageous embodiment of the invention, the transmitter for 5 electromagnetic waves as a laser, in particular as a photo or laser diode, and the receiver for electromagnetic waves as image-resolving sensor, in particular as at least one photocell, is formed. This design of the transmitter and receiver is particularly suitable for determining the data for calculating the tread depth of motor vehicle tires in the above-mentioned procedural ren.

It has proven to be advantageous that the sensor unit is designed to detect the tread depth of the motor vehicle tire over the entire tread. By this measure, not only the tread depth is determined selectively on the tread des5 motor vehicle tire, but can be determined separately at each point of the tread. It has proven to be particularly advantageous in this case that the sensor unit is designed as a rail system in that the at least one sensor can be moved back and forth in order to determine the data for determining the tread depth of the motor vehicle tire over its entire running surface.

Alternatively, it is of course possible to design the sensor unit as a system which has at least two sensors in order to determine the data for determining the tread depth of the motor vehicle tire over its entire tread. The at least two sensors can be arranged stationary in the sensor unit. However, it is also conceivable that the at least two sensors can be moved back and forth in the sensor unit designed as a rail system.

Since it can not be ruled out in normal motor vehicle operation that the individual sensors or the sensor unit are contaminated, depending on the environment in which the motor vehicle is operated, at least one cleaning device is provided for the at least one sensor or for the sensor unit. The cleaning device can have at least one brush. In this case, the brush can be arranged stationarily on the sensor unit, with the individual sensors being able to be moved back and forth via the brush in the sensor unit designed as a rail system, so that cleaning takes place. Alternatively, it may of course be provided that the brush can also be moved back and forth via the sensor unit designed as a rail system, thereby cleaning both the sensor unit itself and the sensors arranged thereon.

According to another aspect of the invention, it is provided that the tread of the motor vehicle tire is at least selectively marked in color when worn to a predetermined tread depth, wherein the color coding is detected by means of the sensor unit. Also by this measure is determined when the motor vehicle tire was worn down to a predetermined tread depth. For example, one or preferably a plurality of colored inclusions arranged distributed over the circumference of the tire may be present in the running surface of the individual tires, which are exposed when the tire tread is worn accordingly. For example, in the new condition of the tire, invisible red inclusions (color markings) may be integrated into the tire tread, the surface of which is exposed upon reaching a minimum permissible tread depth. The then visible on the tire surface red marks can be detected easily and reliably by a responsive to the color red sensor unit, without complicated Calculation methods such as triangulation etc. must be performed. The shape of such color markings may be round, strip-shaped or otherwise, it is only important that in a certain wear condition of the tire, the color mark on the surface of the tire tread is visible.

According to a further development, differently colored markings can be integrated in different depths of the tire tread. A particular first color may then be e.g. indicate a tire with enough profile, a second color disposed deeper in the tire tread may indicate a tread depth indicative of a soon to be due tire change, and a third color located deepest in the tire tread may have a worn, Mark tires worn to the minimum permissible depth permitted by law. The markers with the different colors may be integrated separately into the tire tread, so that only marks of a color are visible on the surface according to the tire wear condition. The sensor unit must be designed in the presence of color markers with different colors so that they can distinguish the different colors and thus clearly detect. Of course, more or less than the aforementioned three different colors can be used depending on the desired accuracy with which a still existing tread depth is to be determined. It is also possible to use colors whose differences are not recognizable to the human eye. For example, different colors may be used which are only illuminated when illuminated with e.g. Infrared light can be seen as different (for a sensor sensitive to infrared light). In this way, color markings can be provided in the tire tread, which are invisible to the human eye, so that a uniform appearance of the tire tread remains guaranteed.

For even more exact profile depth determination by means of color coding, it is provided that the color coding changes continuously as the motor vehicle tire wears. This continuous change of the color coding can be determined by a suitable sensor and the color coding can be assigned a corresponding tread depth.

Furthermore, a display element is provided, which indicates the determined tread depth or wear of the motor vehicle tire to a predetermined profile depth a visual and / or audible warning. Alternatively it is Of course, it is possible to permanently display the tread depth of the individual motor vehicle tires of the motor vehicle permanently in the passenger compartment, for example in the instrument panel of the motor vehicle or via a display unit of an on-board computer or at predetermined intervals.

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To protect the sensors from external influences when they are not in measuring mode, a protective device is provided for each sensor. This protective device is as at least one folding and / or rotatable Schutzbzw. Cover panel formed. Alternatively, it is of course possible for the sensor unit to have a protective plate that is permeable to electromagnetic wave as a protective device.

Furthermore, it is also possible to change the camber settings of the individual wheels of the motor vehicle automatically, for example by a central processor unit, to i5 if it is determined by the device according to the invention that an uneven departure of the individual tires has taken place.

Also, with the device according to the invention, a bar code applied on the tread of the tire can be read. This bar code may, for example, contain information about the tire itself, so that it is pointed out which tire is mounted on the respective rim. Thus, the driver or the service personnel may be advised that the tire is unsuitable for the respective vehicle. Other objects, advantages, features and applications of the present invention will become apparent from the following description of the embodiments with reference to the accompanying diagrammatic drawings. All described and / or illustrated features alone or in any meaningful combination form the subject matter of the present invention, independently of their summary in the claims or their dependency. It shows:

1 shows a car with arranged in the wheel arches embodiments of the device according to the invention, 2a and 2b show an enlarged view of a passenger car in the region of a wheel house with exemplary embodiments of several devices according to the invention,

3 shows a two-wheel with several embodiments of the inventive device,

FIG. 4 shows a detailed view of a device according to the invention during a measuring process,

Figure 5 shows another embodiment of a device according to the invention during a measuring operation, and

FIG. 6 shows cross-sectional representations of inventive devices according to FIGS. 4 and 5 with a protective device arranged thereon.

FIG. 1 shows a passenger vehicle 1 in whose wheel arches 7 different sensor units 3 for collecting data are arranged, with the aid of which the tread depth of the motor vehicle tires 2 is determined.

FIGS. 2a and 2b show enlarged representations of such wheel arrays 7 provided with sensor units 3. In order to compensate for failures of individual sensors 4 and thus provide a redundant system, three sensor units 3 according to the invention are arranged in the wheel arches 7 according to FIGS. 2a and 2b. net, each independently determine the data for determining the tread depth of the motor vehicle tire 2. But it is also possible to equip each wheel housing 7 with more or less than three sensor units 3.

The structure of an embodiment of a device according to the invention is shown in Figures 4 and 5. The sensor unit 3 has two (FIG. 4) or three (FIG. 5) sensors 4, which are each equipped with a transmitter designed as a laser diode 9 and a receiver designed as a photocell 10 for electromagnetic waves or laser radiation. The radiation emitted by the laser diode expands in the direction of the running surface 11 and the profile grooves 16 of the motor vehicle tire 2 and is reflected from there in part again in the direction of the sensor unit 3. This reflected radiation is detected by the receiver designed as a photocell 10. Based on the properties of detected radiation, such as wavelength, phase shift or the like, the distance between the sensor unit 3 and the tread 11 and the profile grooves 16 of the motor vehicle tire 2 can be determined by means of appropriate algorithms. Based on the difference between distance (sensor unit 3 - tread 11) and distance (sensor unit 3 - profile groove 16) can then be determined exactly the tread depth of the motor vehicle tire. In order to be able to determine the distance (sensor unit 3 - running surface 11) and the distance (sensor unit 3 - profile groove 16), the sensors 4 can be moved back and forth transversely to the rolling direction of the motor vehicle tire 2. As a result, the profile depth over the entire running surface 11 of the motor vehicle tire 2 can be determined by each sensor 4 of the sensor unit 3. By using a plurality of sensors 4 in a sensor unit 3, a redundancy is already given within this sensor unit 3.

To further process the data determined by the sensor 4, a transmission unit 5 is provided, which forwards this data to a central processor unit 6. The transmission can be wireless, for example via radio. Alternatively, of course, the transmission unit 5 may also be wired to the processor unit 6. In the processor unit 6, the data determined by the sensors 4 are converted into the tread depth of the motor vehicle tire 2.

In order for the power supply of the sensor unit 3 with its sensors 4 and the transmission unit 5 to be ensured, a power supply device 15 is provided. This power supply device 15 may be connected directly to the car battery. Of course, there is also the possibility that separate energy supply devices 15 are provided, which may consist for example of accumulators, batteries or solar panels.

The profile depth of the motor vehicle tire determined by the processor unit 6 can be displayed to the driver or the maintenance personnel in the passenger compartment, for example in the instrument panel or via a display of the on-board computer.

It is provided that the driver an acoustic and / or visual warning signal is displayed when the tread depth has reached a previously entered into the on-board computer or the central processing unit 6 border area. The warning can also be that the driver is asked to make a change of the vehicle tire 2 within a certain distance. In the figure 6 further embodiments of a device according to the invention are shown schematically. The local sensor units 3, however, operate on the same principle as the embodiments shown in FIGS. 4 and 5 and described above. In the two exemplary embodiments of the sensor units 3 shown in FIG. 6 in the upper 5 region, which each have only one sensor, a protective device 14 for the sensors 4 is provided. In the local upper example of a sensor unit 3, a hinged by means of a hinge, designed as a protective shield protection device 14 is provided. This protective device 14 is only opened when a measuring operation takes place. In all other cases, the protective device 14 covers the sensor unit 3 in such a way that the sensors 4 are protected against external influences. In FIG. 6, a plurality of cross sections of such a foldable protective device 14 are shown in the left-hand area.

The lower example of a sensor unit 3 in FIG. 6 has a different protective device 14. This consists of a material permeable to electromagnetic waves and thus protects the sensors 4 located in the sensor unit 4.

FIG. 3 shows a motor vehicle 1 in the manner of a motorcycle. The motorcycle has in its fenders devices according to the invention, wherein the Ar

2o beitsweise the previously described corresponds. Here too, the sensor units 3 have corresponding sensors 4, which determine data for determining the tread depth of the motor vehicle tire 2. This data is transmitted again in this embodiment by means of a transmission unit 5 to a central processing unit 6, which determines the profile depth of the motor vehicle tire 5 2 from these data.

However, the present invention is not limited to the field of land vehicles equipped with motor vehicle tires. Rather, the invention can also be used for watercraft and aircraft, which should also be equipped with corresponding 0 vehicle tires. These can be, for example, amphibious vehicles and also airplanes. LIST OF REFERENCE NUMBERS

1 motor vehicle

2 motor vehicle tires

3 sensor unit

4 sensor

5 transmission unit

6 processor unit

7 wheel arch

8 fender

9 laser diode

10 photocell

11 tread

12 cleaning device

13 brush

14 protective device

15 energy supply

16 profile n ut

Claims

claims

5 1. A device for measuring the tread depth of motor vehicle tires with at least one sensor unit for detecting the tread depth of a motor vehicle tire, characterized in that in a motor vehicle (1), in particular in a land, air and water vehicle, each motor vehicle tire (2) at least one Sensor unit (3) for detecting the tread depth of the motor vehicle tire (2) and / or lo whose change is associated.

2. Apparatus according to claim 1, characterized in that each sensor unit (3) has a sensor (4).

3. Device according to one of the preceding claims, characterized in that each sensor unit (3) is assigned a transmission unit (5) which forwards the data determined by the sensor unit (3) to a central processor unit (6) arranged in the motor vehicle ,

20 4. Device according to one of the preceding claims, characterized in that the sensor units (3) continuously determine the tread depth of the motor vehicle tire (2).

5. Device according to one of claims 1 to 3, 5 characterized in that the sensor units (3) determine the tread depth of the motor vehicle tire (2) at predetermined time intervals.

6. Device according to one of claims 1 to 3, characterized in that the sensor units (3) determine the tread depth of Kraftfahr- 0 zeugreifens (2) on the instruction of an operator.

7. Device according to one of the preceding claims, characterized in that each sensor unit (3) has at least two sensors (4). 5

8. Device according to one of the preceding claims, characterized in that the sensor units (3) in the wheel arch (7) relate approximately on the mudguard (8) of the motor vehicle tire (2), whose tread depth is to be determined, is arranged.

9. Device according to one of the preceding claims,

5 characterized in that each motor vehicle tire (2) are associated with three sensor units (3).

10. Device according to one of the preceding claims, characterized in that the sensor (4) consists of a transmitter and a receiver for electromagnetic electromagnetic waves GE.

11. Device according to one of claims 1 to 9, characterized in that the sensor (4) consists of a camera.

12. Device according to one of claims 1 to 9, characterized in that the sensor (4) consists of a transmitter and a receiver for pressure waves.

13. Device according to claim 10,

20, characterized in that the transmitter for electromagnetic waves as a laser, in particular as a photo or laser diode (9), and the receiver for electromagnetic waves as image-resolving sensor, in particular as a photocell (10) is formed. 14. Device according to one of the preceding claims, characterized in that the sensor unit (3) for detecting the tread depth of the motor vehicle tire (2) over its entire running surface (11) is formed.

15. Device according to one of the preceding claims, 0 characterized in that the sensor unit (3) is designed as a rail system in which the at least one sensor (3) is movable back and forth or pivotable about the tread depth of the motor vehicle tire (2) to determine its entire running surface (11). 5

16. Device according to one of claims 1 to 15, characterized in that the sensor unit (3) is designed as a system which has at least two sensors (4) to the tread depth of the motor vehicle fens (2) over its entire tread (11) to determine.

17. The apparatus of claim 15 or 16, characterized in that the sensor unit (3) has at least one cleaning 5 direction (12) for the at least one sensor (4).

18. The apparatus according to claim 17, characterized in that the cleaning device (12) has at least one brush (13).

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19. Device according to one of the preceding claims, characterized in that the running surface (11) of the motor vehicle tire (2) is at least selectively colored when worn to a predetermined tread depth, wherein the color coding is detected by means of the sensor unit (3) i5.

20. The apparatus according to claim 19, characterized in that the running surface (11) of the motor vehicle tire (2) in different profile depths at least selectively colored differently marked 20 is characterized, wherein the different color coding detected by the sensor unit (3) and assigned to a tread depth become.

21. The apparatus of claim 19 or 20, characterized in that for color identification at least one pin with 5 over its longitudinal extent changing color is embedded in the motor vehicle tire.

22. Device according to one of the preceding claims, characterized in that a display element is provided, which indicates the ermit- telded tread depth or at wear of the motor vehicle tire (2) to a predetermined tread depth warning.

23. Device according to one of the preceding claims, characterized in that a power supply (15) for the sensor unit (3) 5 and / or the transmission unit (5) is provided.

24. Device according to one of the preceding claims, characterized in that for each sensor (4) a protective device (14) is provided, which protects the sensor (4) against external influences when it is not in the measuring mode.

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25. The apparatus according to claim 24, characterized in that the protective device (14) is designed as at least one folding and / or rotatable protective or cover panel.

26. Device according to one of claims 3 to 25, characterized in that the transmission unit (5) wirelessly, for example via radio, with the central processor unit (6) communicates.

27. Device according to one of claims 3 to 25, i5 characterized in that the transmission unit (5) for communication with the central processor unit (6) with this cabled.