MXPA98005901A - Device to test plains - Google Patents

Abstract

A tire testing device comprising an air pressure control element for changing the tire pressure of a wheel, a test head and a computer, which before and after a change in air pressure respectively with radiation coherent produces an interferogram of the surface of the rim and converts the interferogram into a module-2 (PI) image, which in turn is processed to give an image of gray values, and in which from a comparison of images of gray values information is obtained about the defects present in the rim, a positioning element for the test head, with which the test head is going to be placed to produce interferograms at a predetermined distance from the rim, and a control element for rotating the wheel in increments by an amount equal to a test segment, when the examination of the previous test segment ends, in which an elemnt meets device for producing the interferograms, an electronic control element for the optical element and the air pressure control element in the test head and in which a sequence control element for the rim and element verification apparatus is provided to evaluate the interferogram in the computer. If the wheel drive control element serves for the operation of a blanking machine for further rotation segment by wheel segment, the computer of the rim verifying apparatus is integrated into the computer of the balancing machine. If a pulse roller set of a brake test dynamometer is used, on which the motor vehicle with the wheel bearing the rim to be checked, for rotation by segments of the wheel, the computer of the apparatus of the tire is integrated into the computer of the brake test denamometer

Description

DEVICE TO TRY TIRES The invention relates to a tire testing device comprising an air pressure element for changing the pressure of a tire, a test head, a computer, which before and after a change in air pressure respectively with coherent radiation produces an interferogram of the surface of the rim and converts the interferogram into a 2p module image, which is processed on its part to produce an image of gray values, and in which from a comparison of the gray values it is they obtain the information images about any defect present in the rim and a control element in order to turn the increasing wheel in an amount equal to a test segment, where the examination of the preceding test segment ends. German Patent Publication 4,231,578 Al discloses a method for determining the structural strength of the rims, in which case a coherent light shines on the rim, the radiation reflected by the rim is divided into two parts of rays in a dual-beam interferometer, in the dual-ray interferometer one of the two ray parts is tilted relative to the other ray part '(trimming), in the ray interferometer one of the two parts of the radiation is shifted by phase increments, one component which represents the radiation due to the reflectance from the test object, which is divided into two parts of rays, recombines in the dual-beam interferometer and components that form an image of the surface of the rim with a large aperture, to an electronic image sensor system and the signals at the output of an image sensor system are digitized and subsequently processed in an image processing system to give an image of module-27T, and the image of module-2p is confirmed as the image of output gray values. According to the publication of the German patent 19,502,073 Al the above-mentioned method is further developed by partially differentiating both the output gray values image that produces a second gray value image, identical to the gray output value image and it is shifted geometrically in relation to the output gray value image in the direction of the cut it modifies by a gray value, which is constant over the entire range of the image and the second gray value image, manipulated in this way , it is subtracted from the output gray value image so that the resulting gray value image is produced, in which any defect in the rim that may occur can be recognized. When it is considered that a structural damage to the automobile rims, more particularly in the carcass including the band, can substantially reduce the safety of the motor vehicle, it will be desirable to perform a tire check at regular intervals. In the patent application of the German patent publication P 197 24 463 5, which is hereby incorporated by reference, there is the purpose of verifying a rim by mounting the wheel, which holds the rim to be verified, in a Rolling wheel machine and moving the test head until the rim is at a previously determined verification distance to produce an interferogram. The verification of defects in the rim is made in a first segment of the rim. Then the wheel is rotated further by the balancing machine in an amount equal to the verified segment and the last mentioned steps are repeated until all the has been verified. tire. The test device, accordingly, comprises a balancing machine, in which the wheel supporting the rim to be checked is mounted, a positioning element for a test head with which the test head can be moved up to the rim as well as a previously determined distance of verification or test to produce an interferogram, and a control element for the balancing machine in order to rotate the wheel an amount equal to a verification segment. In the patent application of German patent publication P 197 24 463.5, which is incorporated herein by reference, there is a purpose of verifying a rim by mounting the wheel, which holds the rim to be verified, on a set of rollers driven. The tire verification includes an air pressure element to change the pressure of the tire and also a test head and a computer. In addition, the apparatus comprises at least one driven roller assembly in which the motor vehicle with the wheel, which holds the rim to be verified is driven, a positioning element for the test head with which the head of Test can be moved towards the rim to be at a predetermined distance from it to produce interferograms and a control element for the set of rollers in order to make it rotate an amount equal to the size of a verification segment, when complete the verification of the preceding segment. An object of the invention is to create a tire verification apparatus, which allows the verification of the tires as part of the service operations on the wheels of a motor vehicle or as part of a general technical examination of a motor vehicle, which must be done from time to time, and in this respect the computation and evaluation operations can be carried out as quickly as possible and with the minimum complexity of structural hardware.

For this purpose, the tire verification apparatus of the invention is characterized in that an optical element for producing the interferograms, an electronic control element for the optical element and the pressure control element are brought together in the test head and because a sequence control element for the verification apparatus and an element for evaluating the interferogram are provided on the computer. As far as this division is concerned, even the optical and electronic units in the test head and in the main computer (PC) achieve a rapid evaluation with a relatively small amount of structural and hardware complexity. According to an advantageous development of the verification apparatus of the invention, the test head comprises a central processing unit (CPU), the electronic control element for the optical element and the air pressure control element and the same it is connected via an interface with the computer. According to the above, all functions in the test head can be coordinated using a single serial interface, such as an RS-232 inferred, with the computer element (PC). According to another advantageous development, the tire verification apparatus of the invention, wherein the optical element comprises a video camera, laser diodes and a piezoelectric element, is characterized in that the electronic control element controlled by the computer for the optical element it comprises a laser diode control element and a control element or impeller of the piezoelectric element. Another preferred embodiment of the invention is characterized in that the air pressure control element comprises an air pressure sensor and a valve driver, the solenoid valve being controllable both with respect to the size of its opening and the opening time. In this respect it is more an advantage for the air pressure control element to reduce the pressure of the rim during each step of verification during a step and after the completion of the verification return it to the nominal pressure. In an advantageous mode, the structural complexity is further reduced by checking the rims according to the invention because an electric power source for the electronic units of the head is integrated in the test head. A further advantageous development of the invention is characterized in that a busbar system, preferably an I2C busbar, is provided for the connection of the test head units. With respect to the speed of operation of the test head, it is an advantage for the electric units of the test head to be assembled in a board, which preferably also comprises the source of electrical energy. A further advantageous development of the invention is characterized in that a busbar of the system, preferably an I2C busbar, is provided for the connection of the central processing unit with the control element of the piezoelectric element of the test head. An advantageous additional design of the tire verification apparatus of the invention, wherein the pulse control element of the wheel of a balancing machine serves for the rotation by segment increments of the wheel is characterized in that the computer of the verification apparatus The tire is integrated into the computer of the balancing machine. In other words, the computer performs its function both during the rolling of the wheels and also during the verification of the tires. In the case of the aforementioned modality it is an advantage for the synchronization to be connected to the arrow of the balancing machine to detect the additional rotation of the arrow and make the computer respond to it, which then turns off the motor impulse. , when the wheel rotated more than one segment of verification. This synchrony is present in any case in conventional balancing machines so that structural complexity does not increase. Yet another advantageous design of the tire verification apparatus of the invention, wherein at least one set of driving rollers of the brake test dynamometer, in which the motor vehicle is to be driven having a wheel, which holds the rim to be verified, serves for the rotation in increments by Wheel segments are characterized because the computer of the tire verification device is integrated into the brake test dynamometer computer. In the embodiment of the invention mentioned above it is an advantage that the sensor roller is provided, which detects rotation by increments of the tire and via synchronization causes the computer to respond to that rotation, turning off that computer the motor impulse, when the rim has rotated more or has rotated along a segment of verification. Consequently, the roller set of the brake test dynamometer is adapted to the requirements of the tire verification with a minimum of complexity. Finally, an advantageous development of the verification apparatus of the invention is characterized in that the motor for the incremental rotation of the wheel is driven via a frequency converter, which can be controlled by the computer. A further understanding of the nature and advantages of the present invention will be obtained with reference to the remaining portion of the specification and the drawings. Figure 1 is a diagrammatic plan view of a balancing machine as a first working mode of the tire verification apparatus of the invention. Figure 2 is a front view of one end of the test head of the verification apparatus as in Figure 1. Figure 3 shows a block diagram of the tire verification apparatus according to the first embodiment. Figure 4 is a diagrammatic plan view of a roller assembly of a brake test dynamometer as a second embodiment of the tire testing apparatus of the invention. Figure 5 is an end front view, diagrammatically, of the apparatus according to Figure 4. Figure 6 is a block diagram of the tire verification apparatus according to the second working mode. Figure 7 is a block diagram of the optical and electronic units of a test head. Figure 1 shows a balancing machine 2 with a keyboard 4 and a monitor 6, which are accommodated in a housing 8. A wheel 10 with a rim 11 is mounted on an axis of the balancing machine 2 by means of an element of fast release grip 14, which engages a hub 13 (Figur 2) of a wheel 10. In the housing 8 of the balancing machine 2 s a test head 16 is attached by means of two parallel arms links 18 and 20. The arm 20 has one end pivoted in a holder 22 in the housing 8. A joint 24 connects the arm 20 to the arm 18 and the arm 18 is connected via a joint 26 to the test head 16. Accordingly, the The test head 16 can be pivoted from a position (not shown) where it is turned outwardly on the housing 8, in a verification position (Figure 1), where it is opposite to the wall of the rim 11 in the position of check. A handle is provided on the test head 16 and has a push-button switch (not shown), by which the positioning element (parallel links or arms 18 and 20) can be stopped, when the test head 16 reached the verification or test position. The air pressure element comprises a pressure hose 40 and a valve 42 with an air pressure sensor, the valve 42 being adapted to be mounted on the valve of the rim. A control element for the air pressure element is provided in the test head 16. The control element in the test head 16 is connected via a cable 30 to the valve which is designed in the form of a solenoid valve, and to the air pressure sensor d, which is integrated into the valve. The valve 42 can be adjusted both with respect to its opening (setting the delivery rate per time unit) and also to open and close it so that a change in the pressure is established in the rim both by the opening degree of the valve as well as the opening time of the valve. The test head 16 can be seen in figure e as an end front view and the laser diodes 44, which serve to produce interferograms, will be seen. In addition, two diodes 46 and 48 are provided, which serve to establish the distance between the test head 16 and the sidewall of the rim 11 during the test. To this end, the two laser diodes 46 and 48 are set obliquely in the visible range in which the laser beams thereof are at an angle against each other and intersect at that point, which corresponds to the test distance between the test head and the side surface of the rim. When the test head 16 moves towards the rim 11, the verification distance will be reached, when the two laser beams collide at a point on the side wall of the rim 11. Subsequently, a target 45 of a camera is plotted. , which takes images of the tire that is going to be verified. The speed of rotation of the motor of the balancing machine is thus controlled by a variable frequency converter that the motor runs at a relatively low, constant rotation speed. A synchronization on axis 12 detects the speed of the axis and produces an output signal, which corresponds to the amount, by which the tire has rotated. The synchronizer output signal is used in the computer to shut down the drive motor, when the tire has rotated in increments along a verification segment. In the case of the working mode illustrated in Figure 2, a verification segment is equal to 1/8 of the total periphery of the rim so that the rim must be rotated seven more times to verify the rim completely. The test head 16 is connected to a conductor for the power supply to the test head and a data line which is conducted to the counting unit. The motor to drive the axis of the balancing machine and the synchronizer on the axis of the balancing machine are also connected to the computing unit, those connection conductors and the computing unit are omitted in order to make the drawings more clear. A central computing unit is provided for controlling the functions of the tire verification apparatus, the computer unit being integrated with the computer of the balancing machine so that the complexity of the hardware does not increase. In addition, the monitor to display the results of the measurement is also used for the balancing and for the verification of the rim, the information on both verification operations being shown on the same monitor. Figure 3 shows a block diagram of the first modality of the tire verification apparatus. The central computing unit 50, which is illustrated in the form of a PC, conventionally has several "com" ports. A mouse 52 connects to the port com 1. The port com 2 is used for a control element of the balancing machine 54, which essentially comprises the control for the drive motor of the balancing machine and is also responsible for the rotation by increments segment by segment of the wheel during the verification of the same. The test head 16 is connected to the com port 3, while the video camera present in the test head is connected via a conductor 56 to the frame clamp 58 in the computation unit 50. The design of the head of the head test 16 will be described later, while connections for the keyboard and monitor of the computing unit 50 are omitted in order to make the drawing clearer. The manner of operation of the tire verification apparatus is as follows. First the wheel that holds the rim to be checked is mounted on a balancing machine, the arrow of the balancing machine being able to rotate under the control of a computer both for the rolling of the wheel and also for the verification of tires at different speeds of rotation. The next step is for a test head to move towards the rim as much as a previously determined verification distance to produce interferograms and stop at this position. After mounting the rim on the balancing machine, the air pressure valve connects to the rim. Before carrying out the first verification sequence, the specific information of the wheel and, respectively, the information for the incremental rotation of the axis of the balancing machine, such as the duration of the pulse at constant speed of rotation, which depends of the dimensions of the wheel that are supplied to the computer or obtained from a look-up table. Then verification is made on a first segment of the rim according to the method as initially mentioned. After the first verification segment was examined, the wheel is rotated incrementally according to the size of a verification segment using the axis of the balancing machine, the axis of the balancing machine being controlled via a computer. a way dependent on the output signals of a synchronizer on the axis of the balancing machine. When the next segment of the rim is brought to its position, the test head is activated in order to verify the next segment.

After which, as many verification sequences as incremental rotation movements are made, it is necessary to verify the complete rim. In each verification sequence there is, as indicated above, a reduction in pressure between a first series of interferograms and a second series, that reduction in pressure is also controlled by the computation unit. The reduction in pressure is carried out in accordance, in steps, by starting the pressure at the nominal pressure that is reduced by one step in each verification sequence. After the conclusion of the air pressure check the rim is returned to the nominal pressure, the valve and the control elements connected with it are also used. With reference to Figures 4 to 6, a second working mode of the tire verification apparatus of the invention will now be described. Illustrated is a roller assembly with two rollers 64 and 66 of a brake test dynamometer 62 of which the roller 64 is driven by a motor 68. The other roller 66 rotates freely. A respective sensor roller 76 is disposed between the rollers of the roller assembly. The sets of rollers and the driving motors of the brake test dynamometer are arranged in a cavity in the floor. A vehicle is driven in the direction of the arrow F on the roller assemblies so that for example its front wheels are arranged in the two sets of rollers. In Figure 4 a front wheel 78 of a motor vehicle is indicated, whose wheels are to be checked. Figure 4 further shows a front wheel 80, which has a diameter smaller than the wheel 78 and belongs to another motor vehicle. The different sizes of wheels 78 and 80 only serve to explain the manner of operation of this embodiment of the invention. A test head 90 is mounted by two pivoting arms 94 and 96 on a column Z 92 capable of moving in the direction of arrow Z 92 in Figure 5 vertically. Accordingly, the test head 90 can be easily moved in the position with the correct verification distance from the side surfaces of the rim 78. Then the pivoting arms 94 and 96 and also the column Z are stopped. The air pressure element comprises, as in the first embodiment, a pressure hose and a solenoid valve, which can be mounted on the valve of the rim. The valve can be adjusted both with respect to its opening (setting the amount of supply per unit of time) as well as opening and closing it so that the change in tire pressure can be as much. by the degree of opening of the valve as well as by the time during which the valve is open. The air pressure control element in the test head 90 is connected via a cable (not shown) to the air pressure sensor and the solenoid valve. A handle 97 is provided on the test head 90 and with it the test head can be moved manually along three axes until the verification position is reached, when the verification position is reached, the stop elements of the three slides are activated using a push button switch, which is provided on the handle 97. The test head 90 disposed on the column 92 is shown in Figure 5 in a front end view and the laser diodes will be seen 98 which are used to produce the interferograms. In addition, two diodes 100 and 102 are provided, which serve to establish the correct distance between the test head 90 and the side wall of the rim 78. To this end the two laser diodes 100 and 102 are set obliquely in the visible range in which are the spokes of the same at an angle to each other and intersect at that point, which corresponds to the test distance between the test head and the side wall of the rim. When the test head 90 moves towards the rim 78, the verification distance will be reached, when the two laser beams form a point on the side wall of the rim 78. Subsequently a lens 104 of a camera diagrammatically represented, which takes images of the rim to be verified. The rotation speed of the motor 68 is thus controlled by a variable frequency converter (not shown) from the central counting unit of the tire checking apparatus that the motor runs at a constant, relatively low rotation speed. The sensor roller 76 engages the rim in order to produce, via the synchronizer, an output signal, which is equal to the amount by which the rim has rotated. The synchronizer output signal of the sensor roller 76 is used in the computer to shut down the drive motor when the rim has rotated incrementally along a check segment. In the case of the working mode illustrated in Figure 5, a verification segment is equal to 1/8 of the total periphery of the rim, so that the rim must rotate seven times more in order to verify the rim completely . The position of the test head 90 'is indicated in dotted lines and is provided with the reference numerals 90', 94 'and 96' .. As shown in Figure 4 it is possible to move the test head 90 in the position at the correct distance both in the case of large wheels such as the wheel 78 and also in the case of small wheels such as the wheel 80. A central counting unit is provided to control the functions of the tire checking apparatus, the latter being integrated computer unit with the computer of the balancing machine so that here also the complexity of the hardware is kept low. In addition, the monitor to display the results of the measurement is also used for the brake test and to verify the tire, the information on both verification operations is displayed on the same monitor. The manner of operation of the working mode described above of the tire tester apparatus of the invention in a brake test dynamometer is analogous to the manner of operation of a tire tester apparatus of the invention in a balancing machine as described previously. The difference is that the two sets of rollers of a brake test dynamometer can run under the control of the computer both to perform the brake test and also to test the tires with different speeds of rotation. Figure 6 shows a block diagram of the second working mode of the tire checking apparatus. The central computing unit 50, which is represented as a PC, conventionally has a plurality of "com" ports. A mouse 52 connects to port com 1. The port com 2 is connected to a brake test dynamometer 93 control element, which essentially comprises the control for the driving motor of the brake test dynamometer is also responsible for the rotation by increments of the wheel during the verification of the rim. The test head 90 is connected to the com port 3, while the video camera present in the test head is connected to a connector 105 with the frame clamp 58 in the computation unit 50. The design of the head of test 90 will be described in more detail below, while connections for the keyboard and monitor of the computing unit 50 are omitted in order to make the drawing clearer. A second test head 91 is connected by means of a connector 106 to the frame clamp 58. In this working mode the frame clamp 58 is used to process the output signals of both test heads 90 and 91. FIG. 7 shows a block diagram of the optical and electronic units of the test head, such as, for example, the test head 16 or the test head 90 and 91. An optical element 110 is provided in the test head 16 to produce the interferograms, which comprises a video camera 112, the laser diodes as well as the piezoelectric element 116. In the optical element the light diffusely reflected back from the rim goes to the objective of a video camera. The light that passes through a Michelson interferometer, in which the ray of light is first split with a slit of the ray in two parts of rays. After reflection in the mirrors, the ray portions are recombined before passing to the objective of the video camera 112. In the Michelson interferometer, using a fixation element it is possible for one part of the image to be tilted in relation to the other part. of image. This leads to two mutually displaced images of the side wall of the rim. With the help of a piezoelectric element it is possible that the second part of rays moves in a minimum of steps. This function is used to determine the phase relationship of the reflected light diffusely and in accordance with this for the determination of the deformation. The signal from the video camera 112 (CCD camera) is supplied via the BNC connection 114 (Figure 7) to the frame clip 58, which is provided in the counting unit 50. An electronic control element for the optical element 110 it comprises a diode control element 116 and a piezoelectric control element 118. The air pressure control element includes an air pressure sensor 120 and a solenoid valve driver 122. Finally, Figure 7 shows a supply of energy 124 for the electronic units in the test head. The electrical units are controlled by a central processing unit computer 126, which is connected by means of an RS-232 controller 128 to the computing unit (PC) 50, in which a sequence control element of the verification apparatus of tires is provided together with elements to evaluate the interferograms. Each of the test heads 16, 90 and 91 operates as an autonomous system. The control is obtained from the counting unit 50 through a series inferium and the RS-232 controller 128. According to the above the piezoelectric element 116 to produce special images (wavelength shifts), the diodes laser 44 and 98 for illuminating the side walls of the rim, the laser diodes 46, 48, 100 and 102 to set the distance of the tire test heads, the video camera 112 to produce an image, the air pressure sensor 120 to check the tire pressure, the solenoid valve controller 122 for solenoid valve 42 control and a serial interface are to be operated via controller 128. The system is thus designed via a busbar of the series system 117, preferably an I2C busbar, the groups of individual components can be controlled via the central processing unit 126. The elements related to security of the verification apparatus, as for example the condition that the lighting laser diodes, for example the diodes 44, can only turn on when a rim is in opposition to the test head, consequently they are not under the control of the unit of computation 50, since the elements of the computing unit are secured by software and hardware independently of the computing unit 50. Due to the architecture of the system and series it is also possible, that future options are adopted if problems. Upward expansion up to a maximum of 128 component groups is possible. For example, LCD displays, infra-red remote control elements, LED display elements, relay outputs, semiconductor outputs, additional analog and digital outputs and more key areas are possible. Due to the architecture of the system it is more possible especially to operate all the component groups in the test head, including the control of the air pressure, using a single interface. Each test head is connected by commercially available assembly cable to the main power supply. It can be operated in a voltage range of 90 to 260 V at a frequency of 40 to 400 Hz without change elements. Following internally the power supply 124 all the component groups including the video camera 112 and the piezoelectric element 116 are supplied with 12 V DC. The system, consequently, it is safe to the touch. The high voltage for driving the piezoelectric element 116 is locally produced in the piezoelectric control element The component groups of the individual system component are connected together by a flat cable in busbar technology, ie, via the busbar of the system 117 The wiring is, therefore, extremely simple. Another advantageous feature is possible if the power supply 124 and the remaining component groups 116, 118, 120, 122 126 and 128 are put together in a board, a busbar of the system, preferably an I2C busbar being provided only for driving an amplifier piezoelectric in the control element 188 for the piezoelectric element. This means that there is a further simplification of the tire verification apparatus of the invention with respect to structural and hardware complexity. It should be understood that the foregoing description is intended to be illustrative and not restrictive. Many modalities will be apparent to those skilled in the art after reviewing the above description. Those skilled in the art will recognize as an equivalent or alternative method of tire testing and the combination of a tire testing machine with a wheel balancing machine. The scope of the invention should therefore be determined not by reference to the foregoing description, but instead, should be determined with reference to the appended claims throughout the full scope of equivalence to which claims are entitled.

Claims (17)

1. CLAIMS l. A tire test device comprising an air pressure element for changing the tire pressure of a wheel, a test head and a computer, which before and after a change in air pressure respectively with coherent radiation produce an interferogram of the surface of the rim and convert the interferogram into a module-27r image, which in turn is processed to produce an image of values in gray, and in which from a comparison of the values in gray it is they obtain images of information about the defects present in the rim, a positioning element for the test head, with which the test head is to be placed to produce interferograms at a predetermined distance from the rim, and an element of control in order to rotate the wheel in increments by an amount equal to a test segment, when the examination of the previous test segment ends, where a) an In order to produce the interferograms, an electronic control element for the optical element and the air pressure control element are brought together in the test head and where b) a sequence control element for the verification apparatus and An element to evaluate the interferogram are provided in the computer.
2. 2. The apparatus as claimed in claim 1, wherein the test head comprises a central processing unit that is provided for the electronic control of the optical element and the air pressure control element and is connected via an interphase. With the computer.
3. 3. The apparatus as claimed in claim 1, wherein the optical element comprises a video camera, laser diodes and a piezoelectric element, wherein the electronic control element controlled by the computer for the optical element comprises a control element. of the laser diodes and a control element of the piezoelectric element.
4. The apparatus as claimed in claim 1, wherein the air pressure control includes a pressure sensor and a solenoid valve driver.
5. The apparatus as claimed in claim 1, comprising a valve that can be controlled both with respect to the size of its opening and with respect to the opening time.
6. 6. The apparatus as claimed in the claim 5, which comprises an air pressure control element for controlling the pressure in the rim, the pressure in the rim being reduced during each step of verification in one step and after the conclusion of the verification is returned to the nominal pressure.
7. 7. The apparatus as claimed in claim 1, wherein a power supply is integrated into the test head to supply it to the electronic units of the test head.
8. 8. The apparatus as claimed in the claim 1, wherein a busbar of the system is provided, preferably an I2C busbar for connecting the electronic units of the test head.
9. 9. The apparatus as claimed in claim 1, wherein the electronic units of the test head are mounted together on a board.
10. 10. The apparatus as claimed in the claim I, where the electronic units of the test head as well as a power supply are integrated into the test head to supply it to the electronic units of the test head are mounted together on a board.
11. The apparatus as claimed in claim 3, wherein a busbar of the system for connecting the central processing unit to the control element of the piezoelectric element of the test head is provided.
12. 12. The apparatus as claimed in the claim II, wherein the busbar of the system is an I2C busbar
13. 13. The apparatus as claimed in claim 1, wherein the driving element of the wheel of a balancing machine serves for the rotation in increments by segments of the wheel, where the computer of the tire verification device is integrated into the computer of the balancing machine.
14. 14. The apparatus as claimed in the claim 13, where a synchronizer is connected to the axis of the balancing machine, which detects rotation by increments of the balancing machine and feeds information about the rotation to the computer, which stops the additional rotation of the driving motor, when the wheel has rotated in a verification segment.
15. 15. The apparatus as claimed in claim 1, wherein at least one set of driven rollers of a brake test dynamometer, on which the motor vehicle having the wheel is driven, which holds the rim that is will verify, serves for rotation by increments by segments of the wheel, where the computer of the tire tester is integrated into the computer brake test dynamometer.
16. 16. The apparatus as claimed in the claim 15, which comprises a sensor roller which detects the rotation by increments of the rim and via a synchronizer causes the computer to respond to that rotation, turning off the computer the drive motor, when the rim has passed a test segment.
17. 17. The apparatus as claimed in claim 1, wherein the engine during segment rotation of the wheel is operated using a frequency converter, which can be controlled by the computer. SUMMARY A tire testing device comprising an air pressure control element for changing the rim pressure of a wheel, a test head and a computer, which before and after a change in air pressure respectively coherent radiation produces an interferogram of the surface of the rim and converts the interferogram into a module-2p image, which in turn is processed to give an image of gray values, and in which from a comparison of the images of gray values you get information about the defects present in the rim; a positioning element for the test head, with which the test head is to be placed to produce interferograms at a predetermined distance from the rim, and a control element for rotating the wheel in increments by an amount equal to one test segment, when the examination of the previous test segment, in which an optical element to produce the interferograms, an electronic control element for the optical element and the air pressure control element in the test head meet and wherein a sequence control element for the tire verification apparatus and elements for evaluating the interferogram in the computer is provided. If the wheel drive control element serves for the operation of a rolling machine for additional rotation segment by wheel segment, the computer of the tire checking apparatus is integrated into the computer of the rolling machine. If an impulse roller set of a brake test dynamometer is used, on which the motor vehicle with the wheel bearing the tire to be checked, for rotation by segments of the wheel, the computer of the apparatus The tire check is integrated into the brake test dynamometer computer.