DE2742247A1 - Measuring device operating by reflected light - depends on coordinate axes with darkened quadrants projected on screen and scanned - Google Patents

Abstract

The device measures camber and alignment of a motor vehicle wheels. A light source projects coordinate axes or the like. A mirror is connected to the adjustable workpiece to be measured, deflected from its normal position in accordance with the measured variable, and reflecting the light beam. A projection surface for the light beam and a series of opto electric transducers is placed parallel to the coordinate axis, for automatic scanning of the projected image. At least one quadrant in the image of coordinate axes is darkened, and the rows of opto electric transducers are designed for sequential interrogation of the light-darkness boundary.

Description

Measuring arrangement working according to the reflection method

The invention relates to a dom reflection method working measuring arrangement, with an image of a cross or the like as a measuring beam projecting radiation source and with one with the adjustable to be measured Workpiece connected, according to the measurement.

size deflectable from a normal position, reflecting the measuring beam Mirror as well as with a projection surface for the measuring beam and with one each Row of optoelectrical transducers arranged parallel to the coordinate axes for automatic position scanning of the point of impact of the measuring beam, in particular Arrangement for measuring camber and toe on the wheels of a motor vehicle.

A measuring device for measuring the axles on motor vehicles is known (DT-AS 1 943 463), with one to one. A mirror attached to the wheel of the axle Axis on a screen with a fixed axis cross projected, which at defined points optoelectrical components ur detection of deviations of the projected axbox from the fixed axbox, each optoelectronic component being assigned to a vert of the deviations and the optoelectronic components with a digital display driving Coupling matrix are connected and where the width of the axes of the projected axbox greater than the distance between adjacent optoelectrical components is.

However, this measuring device has the disadvantage that if one fails individual photocell the measured value cannot be clearly determined. Also is not clearly identifiable when the projection area is exceeded, in which direction this is crossed.

The object of the invention is that if a photodiode fails in each If at least an approximate measurement is possible and that if it is exceeded the projection surface can be clearly seen that the projection surface is actually exceeded (not for example failure of a photodiode) and in which direction this is exceeded.

This object is achieved according to the invention in that at least a quadrant of the cross-section of the measuring beam is light-guiding and that the optoelectrical Converter rows are designed for sequential interrogation of the light-dark transition.

By sequential interrogation of the opto-electrical converter can be series the transition from light to dark can also be determined electrically. The wanted The measured value is where an illuminated transducer is followed by a non-illuminated transducer.

Is z. B. a converter is defective, so appear in an interrogation cycle two light-dark transitions one behind the other, so that any error is recognized immediately will. The number of illuminated transducers is therefore a measure of the position of the light-dark transition and thus a measure of the measured values sought for camber and toe.

If the projection area is exceeded, it is through the position of the darkened quadrants clearly identifiable in which direction the projection surface exceeded In the sequential query, on the one hand, all opto-electrical Converter illuminated - if exceeded in the other direction, all unlit.

According to a further feature of the invention, an electrically controllable Coordinate writer, such as B. an oscilloscope, an x-y mirror galvanometer od. Like., Preferably arranged in the field of vision of the fitter adjusting the workpiece and it can be the coordinate recorder through the queried position of the axbox corresponding electrical value pairs can be controlled.

By transferring the measured values to another display area, a more precise determination of the position of the measuring beam, especially in the zero point range, possible. The projection surface has a breakthrough in the zero point area (light beam output).

Furthermore, on the projection surface or on the display surface of the Coordinate writer at least one an excellent point preferably through the display point (zero point) corresponding to the normal position of the workpiece running line as a geometric location of the display when presented at only one - the corresponding - the adjustment points of the workpiece (adjustment line) attached be.

B.i adjustment of one of the adjustment points changes at the same time also the position of the other adjustment point in an unequal relationship. The geometric one Place of all adjustments of only one adjustment point thus forms a curve that depends on Vehicle type can be different. If the other adjustment point is changed first, another curved alignment line is created, which the former in the Crosses the zero point. So both adjustment lines can be attached to the display area be.

When adjusting the head and track, it moves in such a way that only an adjustment point is changed until the measuring beam is on the adjustment line lies. The other adjustment point is then changed until the MoD beam is at the zero point the display area comes to rest In addition, the alignment lines be exchangeable (type change).

Furthermore, the position of the axbox in the coordinate recorder be indicated by a point of light or the like.

In addition, the quadrants of the axbox can be darkened in white these be arranged diagonally opposite one another.

This has the advantage that the projection surface only has two rows opto-electrical converter is sufficient to stop when the projection area is exceeded to be able to see in which direction this has been exceeded.

With a measuring arrangement for toe and camber measurements on the wheels of motor vehicles with pairs on both sides of the motor vehicle in defined Position transverse to the longitudinal axis of the felt, radiation sources fixed at the measuring station with projection surface, each of the two radiation sources can point to the zero point of the be aligned opposite projection surface.

This means that there is an automatic zero point monitoring in the measuring pauses given, i.e. when there is no vehicle in the measuring station.

According to a further feature of the invention, the excellent Point through which the adjustment line runs, that of the target track and the target camber corresponding point and the mirrors can be attached parallel to the wheel plane This has the advantage that the mirrors are attached directly to the wheels can be, the circumferential position of the mirror and the wheel can be arbitrary be.

In order to simultaneously carry out follow-up measurements in the same work step (without Steering angle), the marked point can be the zero point and the mirrors can be in a defined circumferential position relative to the axis of rotation of the wheel and in a defined around the target track and the target camber from the parallel position inclined position deviating from the wheel plane.

Furthermore, a holding device for measuring aids, in particular be provided for mirrors that are at least three circumferentially tired when the wheel is dismantled defined arranged points at the respective belonging to the wheel parallel to Brake anchor plate lying on the wheel plane is supported, whereby the od in the form of pins. Like. trained support points in defined locking points of the brake anchor plate intervention.

Finally, a gravity inclinometer can be attached to the holding device for measuring the circumferential position of the holding device relative to the horizontal be appropriate, which measurement as a measure of the caster angle of the associated wheel serves.

This embodiment of the invention is used to measure the caster angle and also has an independent meaning apart from the toe and camber measurement.

Due to the manufacturing process, they have three attachment points a precisely defined position on the brake anchor plate relative to the steering axis, see above that their inclination to the perpendicular is a measure of the caster of the chassis.

The caster is measured when the chassis is in the straight ahead position, So without steering deflection, and if the axle adjustment of camber and toe is the desired Has setpoints based on a game Ausführungsbei shown in the drawing the invention is to be explained in more detail. It shows Fig. 1 the basic structure a measuring arrangement, FIG. 2 shows an embodiment of a measuring plate, FIG. 3 shows a display surface with drawn adjustment lines.

The measuring arrangement shown in FIG. 1 consists of a projector 1, which a measurement image on a mirror 2, which is attached to the wheel 3, on a Projection area 4 projected. The measuring beam 5 emerging from the projector 1 passes a four-sector diaphragm G, the mirror 2 is at an angle of 2 α are deflected, projected onto the projection surface 4, an axis cross x ' - y '.

The projection surface 4 is also due to the coordinates x-y divided into four sectors and carries a vertical and a horizontal row of opto-electric Converter 7 and 7 '. The other free vertical and horizontal is each with a scale 8 and 8 'provided. The division of the scales 8, 8 'depends on the geometric dimensions the system and results from the definition = 1/2 arctan (h / l).

The opto-electrical converters 7, 7 'are partially in the bright and partly in the dark zone of the measurement image projected onto the projection surface 4. The number of illuminated transducers 7, 7 'is a measure of the position of the semi-dark transition and thus a measure of the measured values sought. The transition between light and dark is made by soquential Queries of the Wandlor 7, 7 'determined, beginning on the right and lower part of the Converter rows. The measured value you are looking for is where there is an illuminated one and an unilluminated one Converter 7, 7 'follows. To a broken one Converters 7, 7 'close immediately recognize, it is also checked whether there is only one light-dark transition during a query cycle is detected. Should a converter 7, 7 'be defective, so that it is in the unlit State the signal emits one illuminated, or vice versa, two appear Light-dark transitions in one interrogation cycle and the foal is recognized immediately and displayed.

When measuring the camber and toe, a clear indication of the Wheel position must be ensured even when the measuring ranges are exceeded. This is achieved by the choice of the gate valve 6 (Fig. 2). If o in measuring range is exceeded, whodon all Wantllor 7, 7 'are illuminated, if it is not reached on the other hand, none of the lights are lit, so full deflection or zero position are displayed.

In order to be able to achieve precise measurements, the mirror 2 must be very precise lie parallel to the Radobeiie. Therefore permanent magnets are provided, the same Hold firmly and form-fit against the wheel hub.

Since the measured values are available in electrical form, the display devices be provided where they can be read conveniently. The measured values can still checked for correctness, registered or otherwise evaluated, e.g. B. to control actuators for automatic suspension adjustment.

The basic setting of the camber-to-track measuring system can be done automatically to be checked. If there is no vehicle on the test bench, the mebbild a provector 1 shown on the opposite projection surface l at Proper adjustment can indicate camber and O toe. This kanii observed visually and based on an electronic check of the eloitric fall-to-track measured values been verified.

The display area 9 shown in FIG. 3 oinos Xoordinatenschreiber is used in particular to adjust toe and camber. The display surface 9 has two curve-shaped adjustment lines lo, 11, which intersect at zero point 12. The adjustment lines lo, 11 steal the geometric location of the display during adjustment at only one - the corresponding - adjustment point of the workpiece. One on the Display area 9 of the coordinate recorder indicated display point 13 gives the dio MeD values for the camber and track of a workpiece. Becomes only one of the adjustment columns adjusted, the display point 13 moves to the adjustment line 10 or 11. As soon as this is reached, is achieved by presenting the other adjustment point accordingly, that the display point moves along the adjustment line to zero point 12. As soon If this is reached, the camber and toe show the target values.

The lag of the Falirwerkes is defined as the angular deviation between a plumb line on the roadway in the middle of the wheel contact area and the projection of the steering axis onto a vertical plane parallel to the longitudinal axis of the drop vehicle. The measurement is carried out with an electronic inclinometer, which is preferably is attached to the brake anchor plate at droi points. These three points of defense Due to the manufacturing process, te have a precisely defined position opposite the steering axis, so that its alignment with respect to the perpendicular one time for the caster angle of the vehicle is. Dor Naciilauf is measured if there is a camber during the axle adjustment and lane have the desired setpoints, i.e. without in the straight-ahead position Steering angle.

A landing gear measuring station according to the invention consists of two projection surfaces 4 for lintel and trail, the projectors 1 and mirrors 2 as well as the tracking measuring devices with inclinometers. The six readings are stored in an electronic, not shown Facility processed, checked for correctness and displayed in a suitable manner.

Claims (11)

Claims measuring arrangement working according to the reflected light method, with a radiation source projecting an image of an axis cross or the like as a measuring beam and connected to an adjustable workpiece to be measured, according to the specifications the measured variable from a normal position deflectable mirror reflecting the measuring beam1 as well as with a projection surface for the measuring beam and with one parallel each to the coordinate axes arranged row of opto-electrical converters for automatic Position scanning of the point of impact of the measuring beam, in the special arrangement for Measurement of camber and toe on the wheels of a motor vehicle, d a d u r c h g e -k e n n n n e i c h n e t that at least one quadrant in the image of the axbox (x'-y ') or the like of the measuring beam (5) is darkened and that the optoelectrical Transducer rows (7, 7 ') designed for sequential removal of the He dark transition are. 2. Measuring arrangement according to claim 1, d a d u r c h g e -k e n n z e i c h n e t that an electrically controllable coordinate recorder, such as a Oscillograph. an x-y mirror galvanometer or the like, preferably in the field of vision of the fitter adjusting the workpiece is arranged and there is the coordinate recorder corresponding electrical position (x'-y ') queried by rlu Value pairs can be controlled. 3. Measuring arrangement according to claim 1 or 2, d a d u r c h g k e n n z e i c h e t that on the projection surface (4) or on the display surface (9) of the coordinate recorder at least one excellent point, preferably through the display point (12) (zero point) corresponding to the normal position of the workpiece line running through it as the geometric location of the display during adjustment only one - of the corresponding - of the adjustment points of the workpiece (adjustment line) is appropriate. 4. Measuring arrangement according to claim 3, d a d u r c h g e -k e n n z e i Not that the adjustment lines (io, ii) are attached interchangeably (type change). 3. Measuring arrangement according to claims 2, 3 or 4, d a -d u r c h g e k n n z e i c h n e t that the position of the axbox (x'-y ') in the coordinate recorder is indicated by a point of light (13) or the like. 6 measuring arrangement according to claim 1, d a d u r c h g e -k e n n z e i c n e t, that with two darkened quadrants of the axbox (x'-y ') this are arranged diagonally opposite one another. 7. Measuring arrangement for toe and camber measurements on the wheels of motor vehicles with pairs on the boid side of the motor vehicle in a defined position quor to the longitudinal axis of the vehicle radiation sources with projection surfaces fixed at the measuring station, d a d u r c h g e -k e n n z e i c h n o t, that each of the two radiation sources is at the zero point the opposite projection surface is aligned. (Y measuring arrangement according to claims 3 and 7, d a d u r c Ii g e k Note that the marked point through which the adjustment line runs, which is the target track and the target camber corresponding point and that the Mirror (2) are attached parallel to the wheel plane. 9. Measuring arrangement according to claims 3 and 7, d a d u r c h g e k e n n z e i c h n e t that the marked point is the zero point (13) and that the mirror (2) in a defined circumferential position relative to the axis of rotation of the wheel (3) and in a defined around the target track and the target camber from the parallel position to Wheel plane deviating inclination are attached. 1o. Measuring arrangement according to claims 8 or 9, d a d u r c h g e k It is noted that a line device for measuring aids, in particular for mirror (2) is provided, which is at least with dismantled wheel (3) three circumferentially defined defined points at each associated with the wheel brake anchor plate lying parallel to the wheel plane, with the in the form of Pins or the like formed support points in defined snap-in points of the Bre.sanksrplatte intervention. 11. Measuring arrangement, in particular according to claim 10, d a -d u r c h g It is not clear that there is a gravity inclinometer on the holding device for measuring the circumferential position of the holding device relative to the horizontal which measurement is appropriate as a measure for the caster angle of the associated wheel (3) serves.