FR2730312A1 - VEHICLE WHEEL BALANCING MACHINE. - Google Patents

Abstract

A rotating spindle (2) to receive a wheel (3), and a device for measuring the radii (R1, R2) and the axial distances with respect to the machine (C1, C2) of the surfaces (10, 11) provided on the wheel rim for applying balancing weights (12, 13) are provided on the machine. A light source (8) is arranged on a carriage (6) so as to be able to rotate around an axis (7) perpendicular to a plane containing the axis of rotation of the spindle (2) and to be able to move with the carriage (6) radially relative to the spindle (2) and in the aforementioned plane. The light ray (9) can be oriented on the wheel (3) parallel to the axis of rotation of the spindle (2) to measure the spokes (R1, R2), and by making an angle with it to measure the axial distances (C1, C2). The light source (8) is connected to position sensors producing signals corresponding to the distance of the light beam (9) to the axis of rotation of the spindle (2) and to the angular position.

Description

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  VEHICLE WHEEL BALANCING MACHINE

  The invention relates to a vehicle wheel balancing machine comprising a rotary spindle for each receiving a wheel and a measuring device for measuring the radii and the axial distances from the machine of the surfaces provided on the rim for applying the weights. balancing, the measuring device comprising position sensors to transform the quantities measured into

machine readable signals.

  DE 41 22 844 discloses a balancing machine of this type for motor vehicle wheels of various sizes and types, which can be fixed to a main shaft of the machine, in which there is provided, for measuring an unbalance relating to one or more balancing surfaces, an exploration device for entering the distances from the balancing surfaces to the machine and for entering the balancing radius. The balancing device comprises an exploration member which can be brought out in a common plane with the median longitudinal axis of the main shaft and provides electrical output signals corresponding to the values explored for an evaluation device in which the measured unbalance values obtained during one or more series of measurements are evaluated to determine the unbalance. The exploration member is produced in the form of an exploration lever which can pivot around one of its ends and parallel to the main shaft in its exploration extended position, comprising an exploration tip disposed at its free end. , and it is equipped with an angular measuring device, which measures an angular position proportional to the balancing radius to be entered. The exploration lever can be extended lengthwise or moved, with its end pivotally mounted on a travel path.

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  determined length parallel to the main shaft. For the measurement, the probe is placed at the place provided for the balancing weight and the pivot angle and the length of exit of the probe are entered. The values explored for the distances from the balancing surfaces and the balancing radius are entered into the electronic evaluation unit before the unbalance measurement to determine the unbalances to be balanced. The known exploration device has the disadvantage that the determination of the balancing radius by the pivot angle of the exploration lever is imprecise and is influenced by the measurement of the balancing surface. In addition, the exploration lever can be damaged if it comes from

  inadvertently in contact with the rotating wheel.

  Another device is known from EP O 565 320 A2 for supplying the geometrical quantities of a rim which are decisive for balancing, in which, by means of a lighting in the form of a slit, a light ray is oriented in the form ply perpendicular to the wheel and from the radius

  reflected, we optically grasp the rim outline.

  As determining quantities, the coordinates of the rim flange and / or of the transition between the rim and the tire are detected, a two-dimensional optical detector explores the image of the rim contour reflected and automatically supplies the coordinates. This device has the advantage that the operator does not have to activate a mechanical explorer, on the other hand, it involves a rim contour whose determining coordinates are sufficiently significant to be able to be "identified" without error by a two-dimensional optical detector . This known device is not suitable for rims having a surface parallel to the axis of the spindle for applying the balancing weights in two

balancing surfaces.

  The object of the invention is, with a balancing machine of the aforementioned type, to increase the precision of the measuring device and to eliminate the risk of deterioration of the measuring device by the rotating wheel. Furthermore, the data necessary for the calculation and application of balancing weights must be able to be measured on the fixed wheel, as far as possible, without disturbances and simply, and they must be reproducible for the application of

balancing weight.

  This object is achieved in accordance with the invention by the fact that a light source for producing a visible light ray similar to an index finger is arranged on a carriage so as to be able to rotate around an axis perpendicular to a plane containing the axis of rotation of the spindle and of being able to move with the carriage along a rectilinear guide track extending substantially radially with respect to the spindle and in the aforementioned plane, or that the light ray can be oriented on the wheel, parallel to the axis of rotation of the spindle to measure the spokes and, at an angle with this axis, to measure the axial distances, and the light source is connected to position sensors which produce signals corresponding to the distance from the light ray to the axis of rotation of the spindle and to

  the angular position of the light ray.

  It is possible by using a light beam instead of mechanical probes to place the moving parts of the measuring device provided for safe exploration and protected in or on the machine housing. During the unbalance determination, the light source can remain stationary in the position last set, because the light beam and the spinning wheel do not interfere with each other, so that in all cases a new adjustment of the light beam for the application of

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  balancing weight is unnecessary. The radial arrangement of the guideway allows direct and precise measurement of the balancing radii. In addition, angular zones are suitable for measuring the distances from the balancing planes using the pivot angle of the light source, since the measurement of the radii is not influenced by this. The embodiment according to the invention also allows, with the aid of the light beam, a precise characterization of the locations for the application of the balancing weights, the application itself not being

bothered by the light beam.

  Another advantageous solution of the above-mentioned aim may, according to the invention, consist in that a light source for producing one or two light rays similar to an index finger is placed on a carriage so as to be able to move along a rectilinear guideway extending substantially radially with respect to the spindle and in a plane containing the axis of rotation of the spindle, or parallel to it, that the light ray or rays can be oriented on the balancing planes , to measure the radii and the axial distances, at fixed angles different from each other, with respect to the guide track, and that position sensors are provided which produce signals corresponding to the distances between the source and the axis of rotation of the spindle. The light source can be mounted self-locking and adjustable by hand, but it can be adjustable by means of self-locking cylinders, for example a lifting cylinder. As position sensors preferably, potentiometers or

stepper motors.

  In another development of the invention, an electronic evaluation and storage unit is associated with the device for determining the quantities

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  geometric features. It is also possible to provide a keyboard by means of which it is possible to start, stop the actuating devices for adjusting the light source and / or trigger the transfer of the signals in the evaluation and storage unit. In order to better examine the balancing position and facilitate the application of the weights, the plane in which the light source can move

  and rotate, can extend horizontally.

  The balancing machine can be operated, according to the invention, so that the light source is brought into an angular position in which the light ray is parallel to the axis of the spindle, then, by radial displacement of the light source, the determining radius is obtained for the application of a balancing weight, which then the light source is moved towards the axis of the spindle in a determined position that by modifying the angular position, the light beam is oriented on a position on the vehicle wheel located in the balancing plane, and thus the appropriate angular position is obtained. To measure the angular position, one can also proceed as follows: the light source is brought into a position in which the light ray is perpendicular to the axis of the spindle, and the angular position of the light ray oriented on the balancing plane is obtained with respect to this position. After determining the radii and the distances, the unbalance can be determined, and then, using the quantities recorded, the light ray can be directed to the balancing position in which the balancing weight must be placed. Here, to apply the balancing weight, the wheel is stopped so that the balancing position is in the plane, preferably horizontal, in which the light ray can move. According to the invention, the position

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  correct balancing can be indicated by the fact that after the unbalance measurement, the light source does not turn on unless the wheel is in the position

  correct angle for applying weights.

  Other details will be explained in more detail below with the aid of exemplary embodiments of the invention shown in the drawing in which: FIG. I is a schematic representation of a balancing machine with a radius pivoting light and Figure 2 is a schematic representation of a balancing machine with two light rays

aligned at a fixed angle.

  Figure 1 shows a part of a balancing machine i comprising a spindle 2 on which is mounted a wheel 3. There is also shown a graduation 4 which extends along a guide track, and lighting which can pivot around an axis 7 mounted on a carriage 6 which can move along the guide track 5 and comprising a light source 8 which produces a light ray 9 of punctual section, similar to an index, formed by a beam of rays parallel. The light source 8 is shown in two different positions A and B. In the output position A, the light source 8 is oriented so that the light ray 9 extends parallel to the axis of the spindle 2. In this angular position of the light source 8, the radii Ru and R2 of the two surfaces 10, 11 of the wheel 3 can be determined, surfaces on which

  provision is made for the application of balancing weights 12, 13.

  For this purpose, the light source 8 is first moved with the carriage 6 radially inwards in position A ,, in which the light ray 9 touches the surface 10 where the balancing weight 12 must be applied. in plane E2 .. By pressing a key, the voltage signal corresponding to this

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  position of a position sensor connected to the carriage 6, is brought to an evaluation and storage unit and is recorded there. The same is done after displacement of the light source 8 in the position A2 for the plane E2 and the balancing weight 13. Next, the light source 8 with the carriage 6 is brought radially inwards in the end position B and a corresponding voltage signal from the position sensor is transmitted to the evaluation and storage unit. By calculating the values of the input signals, the distances are determined

  radials Dl, D2 and the resulting radii Ru, Rz.

  The movement of the carriage 6 with the light source 8 can be carried out either manually or by means of a

  cylinder that can be controlled by buttons.

  In position B, the light source 8 is moved along the guide track 5 in a terminal position close to the spindle, in which its distance from the axis of the spindle 2 takes a determined value, always remaining identical. To determine the distances from the machine Ca, Cz of the balancing planes El, E2, in which the balancing weights must be applied, the light source 8 is pivoted by a touch button which controls a servomotor. position B around the axis 7 until the light ray 9 indicates first on one, then on the other of the surfaces 10, 11 where the respective balancing plane must be E, E2. By actuating corresponding keys, or automatically, the voltage signals produced by an angular sensor connected to the light source 8 are transmitted to the evaluation and storage unit, which from there calculates the angles an, a2, and using

  of the recorded values Dl, D =, the distances Cl, C2.

  After having determined in this way the geometrical places, namely the circles, for the position of the balancing weights, we start the machine

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  balancing. After determining the unbalances, the balancing machine automatically stops the wheel in the position in which the location for the application of the balancing weight 12 of the plane El is in the pivoting zone of the light beam 9. We move then the lamp by hand, or automatically in the angular position a so that the light ray 9 indicates on the surface 10 the place where the balancing weight 12 must be placed. After application of the weight 12, the light source 18 is

  brought by hand or automatically to position a.

  and the wheel 3 is rotated until the balancing location for the application of the second balancing weight 13 is in the balancing plane Ez in the light beam 9. At this location the second balancing weight 13. To balance another identical wheel, it is not necessary to measure again the radii and the axial distances of the balancing planes, on the contrary, the determined values remain recorded until l balancing of another wheel size

  requires a new entry of measured values.

  Until then, the light source remains in the end position B and is only used each time to mark the balancing positions for the application of the weights.

  balancing as described above.

If the guideway is arranged

  horizontally, the unbalance balancing, i.e.

  say the application of balancing weights, is shifted

  of 90 compared to what has been practiced until then.

  Thanks to the appropriately programmed control, the wheel is not stopped for unbalance balancing, with the location not at the top, but on the contrary in the rear position, so that the operator can better examine the location for the application of

balancing weight.

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  In the exemplary embodiment of FIG. 2, the light source 19 emits two index-shaped light rays 20, 21, which make angles font, a4 with the guide track different from each other. To determine the distances CI, Cz and the radii RI, Rz sought, the light source 19 is moved

  exclusively along the guideway 5.

  By moving the light source 19 into position C, the light beam 20 touches the location of the wheel 3 for the balancing weight 12. Therefore, a distance sensor not shown determines the distance D3. The carriage with the light source 19 is then moved to the guide track 5 by hand or automatically using a motor, compressed air or hydraulic drive until, in position D, the light beam 21 touches the location for the balancing weight 12. The distance D4 thus determined, as well as the distance D3 determined previously, serve, after geometric conversion, to determine the quantities sought CI and RI. We obtain in the same way the quantities Cz and Rz for the

weight 13.

  As a variant of the exemplary embodiments shown in FIG. 2, it is also possible to provide a light source which, like the light source 8, produces only a single light ray in the form of an index and which can pivot in two fixed angular positions, in which the light ray is oriented once according to the angle a, and the other time according to the angle

  a4 on the space for the balancing weight.

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Claims (11)

  1. Machine for balancing vehicle wheels, comprising a rotary spindle for each time receiving a wheel and a measuring device for measuring the radii and the axial distances from the machine of the surfaces provided on the rim for applying the weights of balancing, the measuring device comprising position sensors for transforming the quantities measured into signals readable by the machine, characterized in that a light source (8) for producing a light ray (9) similar to an index is placed on a carriage (6) so as to be able to rotate about an axis (7) perpendicular to a plane containing the axis of rotation of the spindle (2) and to be able to move with the carriage (6) along a track rectilinear guide (5) extending substantially radially with respect to the spindle (2) and in the above-mentioned plane or parallel to it, in that the light ray (9) can be oriented on the wheel (3), parallel at axis d e rotation of the spindle (2) to measure the radii (RI, R2), and at an angle with it, to measure the axial distances (C1, C2), and in that the light source (8) is connected to position sensors, which produce signals corresponding to the distance of the light ray (9) from the axis of rotation of the spindle   (2) and at the angular position of the light ray.   2. Vehicle wheel balancing machine, comprising a rotary spindle for each time receiving a wheel and a measuring device for measuring the radii and the axial distances from the machine of the surfaces provided on the rim for applying the weights of balancing, the measuring device comprising position sensors for transforming the quantities measured into signals readable by the machine, characterized in that a source 11 2730312   light beam (19) to produce one or two light rays (20, 21) similar to an index finger is arranged on a carriage (6) so as to be able to move along a straight guide path (5) extending substantially radially with respect to the spindle (2), in that the light ray, or the light rays (20, 21) can be oriented on the balancing planes by making two different fixed angles from each other (a3 , a4) with the guide track (5) of the carriage (6) and that position sensors are provided which produce signals corresponding to the distances (D3, D4) from the light source (8) to the axis of rotation of the spindle (2).   3. Balancing machine according to one of   claims 1 or 2, characterized in that the source   light (8, 19) is mounted so that it can be adjusted to hand and self-locking.   4. Balancing machine according to one of   claims 1 or 2, characterized in that the source   light (8, 19) can be moved by self-locking cylinders. 5. Balancing machine according to one of   previous claims, characterized in that   provides potentiometers as position sensors.   6. Balancing machine according to one of   previous claims, characterized in that   associates with the device an evaluation and storage unit in which the signals from the   positions are processed and saved.   7. Balancing machine according to one of   previous claims, characterized in that   provides a keyboard (7) with keys for controlling the actuator to move the light source (8, 19) and / or keys for triggering the transfer of the signals in the evaluation and storage unit 8. Balancing machine according to one of   previous claims, characterized in that the 12 2730312   plane in which the light source (8, 19) and the light ray (9, 20, 21) can move is substantially horizontal.   9. Balancing machine according to one of   previous claims, characterized in that,   to apply the balancing weight (12 and / or 13), the light beam (9,20,21) can be moved to the angular position corresponding to the axial distance (C1, C2) from the balancing plane (E1, E2) and that the wheel (3) can be stopped in the position in which the balancing location is in the plane of displacement of the light ray (9).   10. Balancing machine according to one of   previous claims, characterized in that,   to apply the balancing weights (12, 13) the light source (8, 19), after the unbalance measurement, only lights up when the wheel is in the correct angular position to apply the weights balancing (12, 13).   11. Balancing machine according to one of   previous claims characterized in that   uses the laser as a light source (8, 19).