WO2017097899A1

WO2017097899A1 - Device for laser measurement system

Info

Publication number: WO2017097899A1
Application number: PCT/EP2016/080247
Authority: WO
Inventors: Michael Wirtz; Uwe Oehme; Tobias KURTE
Original assignee: Horiba Europe Gmbh
Priority date: 2015-12-09
Filing date: 2016-12-08
Publication date: 2017-06-15
Also published as: EP3387396A1

Abstract

The invention relates to a device for a laser measurement system (1) comprising a housing (3) that at least partially surrounds the laser measurement system (1). The housing (3) at least partially has a temperature insulating wall. The housing (3) can be ventilated. A fan unit is provided for the ventilation of the housing (3). The housing (3) can have a special glazing (5) in at least one part of the wall. The special glazing (5) can be an optical glass in order to allow laser beams (4) to pass unhindered and unchanged. The housing (3) can be arranged on a moving console (10). The device can be used in particular in a brake test stand.

Description

Device for laser measuring system

The invention relates to a device for a laser measuring system, in particular for a brake tester.

Braking systems behave differently with regard to their vibrations depending on the vehicle. Therefore, the brake system including its components is already measured during development on a brake test bench with a so-called laser vibrometer (laser measuring system), with which in particular the vibration behavior of the brake during operation can be measured. The vibration characteristics of the vehicle brake are temperature-dependent. For this reason it is known to realize different climatic conditions on the brake test bench with the help of environmental simulation systems.

Laser measurement at temperatures above 0 ° C is possible within the test booth of the brake test bench. In this case, the laser vibrometer can thus be constructed directly in the test cabin.

At negative temperatures (temperatures below 0 ° C), the o.g. Measurement no longer take place within the test bench, since the laser vibrometer is destroyed at temperatures at very low temperatures, or at least can not work reliably.

In order nevertheless to obtain corresponding measurement results, the laser measuring system is usually placed with the test hood open, ie with the test chamber open, outside the test station and from there set up on the vehicle brake to be measured. Often, however, the distance to the measurement object (braking system) is too large to produce a high-quality measurement result, since the distance from the laser system to the built-in vehicle brake in the test bench is too large. The test stand can be subsequently conditioned with the test hood closed to negative temperatures, ie cooled down. If the brake system to be measured has reached the specified low or negative temperature, the test hood and thus the test booth are opened, and the actual laser measurement with the previously aligned laser measuring system can begin. However, there remains only a short time window for the laser measurement, since the test station heats up very quickly with the test hood open. The entire process is very cumbersome, time-consuming and therefore expensive. Laser measuring methods are also known in other industrial fields, in which the measured objects to be measured or tested have very low temperatures, which are in some cases significantly below 0 ° C., and in which, in particular, the sensitive laser measuring instruments have to be protected from these low temperatures.

The invention is therefore based on the object to provide a laser measuring system that works reliably even at very low test temperatures and delivers high-quality measurement results.

The object is achieved by a device having the features of claim 1. Advantageous embodiments are specified in the dependent claims. In particular, the device can advantageously be used for a laser measuring system for a brake test stand. Furthermore, a brake tester is specified, in which the device is used.

With the present invention it will be possible to carry out the laser measurement explained above in connection with the prior art also within the test chamber, independently of the temperature simulated by the air conditioning system.

It is a special housing provided with a housing device for installing the laser metrology. The housing device has a housing which may be temperature-insulated and ventilated. In addition, it may have a special glazing in at least one area.

The actual laser measuring technology is built into the ventilated housing, so that on the one hand the heat of the e.g. three laser heads can be dissipated, and on the other hand, the housing can be kept at the temperature level, which is outside the test bench in the respective hall (positive temperature, about 20 ° C). This is done with a fan connected to the housing with a supply and exhaust hose. The interior of the housing can thus be kept at ambient temperature (hall temperature).

The housing is temperature-insulated and can also be used at temperatures down to -30 ° C or -40 ° C. On the front of the case a special glass is used. The size of the special glass should be such that the laser beams required for the laser measurement can pass unhindered through the special glass. The special glass can be eg a special optical glass. The reflectance of the special glass is exactly matched to the wavelength of the laser beams. Thus, the laser beams can measure almost unhindered through the special glazing, and thus measurements are made possible at an optimal distance to the measurement object. The laser heads can be arranged unchanged, ie, as at higher temperatures, relatively close to the measurement object, ie the brake to be measured.

The frame of the test bench can be equipped with a rail system. On this rail system, a console can be added later, on which the housing for laser metrology can be placed. In this way, the console can be moved with the housing respectively when needed to the test stand. The laser can always be placed in the same place using markers to obtain reproducible measurement results with high quality. This saves about a full day of time for an engineer to set up the system.

The device allows in the first place measurements at negative temperatures in the brake tester or on other test objects. Without this hous- ing or housing, it is only possible to measure outside the test cabin at negative temperatures. This is complicated, time consuming, and produces only poor quality measurement results.

The device with the housing can thus fulfill the following essential functions:

1) Insulation of the housing for use at up to -30 ° C or -40 ° C

2) Ventilate the housing to remove the heat and keep the temperature constant at a positive level.

3) Use of special glazing through which the laser can measure. Thus, a measurement is realized at an optimal distance to the measurement object.

4) Marking / anchoring or fixation of the laser on a mobile console that can drive at the Prüfstationsrahmen. The invention relates to a device for a laser measuring system, comprising a housing which at least partially surrounds the laser measuring system, wherein the laser measuring system has at least one laser device for generating a laser beam directed onto a measuring object, the laser device being arranged in the housing, the housing being at least partially having a temperature-insulating wall, and wherein the housing is vented.

The device can be designed as a device for a brake test stand, wherein the laser measuring system has at least one laser device for generating a directed onto a brake disc of a brake to be tested laser beam.

The device can also be used for other industrial applications in which very high or very low temperatures, which could damage the sensitive laser measuring devices, are applied to the measurement object. For example, an application in an air-conditioner vehicle test bench and / or in a climate wind tunnel is conceivable in which the vehicle is to be exposed to extreme climatic conditions. An application for air-conditioned engine test stands is also conceivable. The laser measuring system works in a manner known per se and can have a laser vibrometer.

A laser vibrometer (also known as a short form for laser Doppler vibrometer) is a measuring instrument for the quantification of mechanical vibrations. It can be used to measure vibration frequency and amplitude. Vibrometers contain a laser which is focused on the surface to be measured (in this case, for example, the brake or the brake disk or another test object). Due to the Doppler effect, the frequency of the backscattered laser light shifts as the surface to be measured moves. This frequency shift is evaluated in the vibrometer by means of an interferometer and output as a voltage signal or digital data stream. A scanning vibrometer allows an areal measurement of vibrations.

The laser device can be arranged in the housing.

The housing may at least partially have a temperature-insulating wall. The housing can be ventilated. For this purpose, a fan device may be provided for ventilating the housing.

The housing may have a special glazing in at least part of the wall.

The special glazing can be an optical glass to allow laser beams to pass unhindered and unchanged. The housing may be mounted on a mobile console, e.g. be arranged a carriage. The console can be positioned between an operating position in which the housing with the laser measuring system accommodated therein is in a measuring position in order to detect vibrations of a brake or perform another measuring or testing task, and a rest position in which the housing is connected to the laser scanner. Measuring system are arranged outside the brake tester to be moved.

A brake test bench is provided, comprising a brake mount for receiving a brake to be tested, a drive device for applying a brake load to the brake, measuring devices for detecting test and measurement parameters of the brake, and a housing device specified above.

The test and measurement parameters of the brake can be the parameters that are usually relevant for testing a brake. These include the drive power of the drive device, the braking power, the support torque of the brake, the speed, the braking force, the temperature development, vibrations, etc.

The device can therefore be used particularly advantageously in a brake tester. Likewise, it is also possible to use the device in other measuring or testing tasks, in which in particular the measurement or test object must be air-conditioned in a special way that deviates considerably from the room temperature. This does not only apply to the temperature (especially low or high temperatures) or humidity, but also to the gas composition in the test chamber (gas in the test chamber may be different from the gas composition of air, eg toxic or otherwise harmful components) , These and other advantages and features will be explained in more detail below with the aid of the accompanying figures with reference to an example. Show it

Figure 1 is a perspective view of an apparatus for a laser measuring system in a brake tester; and

Figure 2 is a perspective view of a console, by means of which the device between a rest position and an operating position is movable.

Figure 1 shows a perspective view of the structure of the device in a brake tester.

The device has a laser measuring system 1 with three laser measuring heads 2, which are enclosed by a ventilated housing 3 and serve to generate laser beams 4. The three laser measuring heads 2 enable a three-dimensional recording of the measuring events with appropriate control and evaluation.

To the housing 3 air is supplied via a supply air, not shown, and discharged via an exhaust duct, also not shown. For this purpose, a blower device, also not shown, is provided. The ventilation of the housing 3 makes it possible to temper the interior of the housing 3 in the manner described above in such a way that the most sensitive laser measuring heads 2 arranged in the housing 3 can be operated in the temperature range predetermined for them. This makes it possible to make measurements with the laser measuring heads 2 on objects whose temperature is outside the predetermined temperature range for the operation of the laser measuring heads 2.

The housing 3 is temperature-insulated, in order to possibly. Also large temperature gradients between the temperatures inside the housing 3 and the outside (and thus the interior of the test cabin 6) to allow. For this purpose, the wall of the housing 3 can carry a corresponding thermal insulation.

At least on the side facing the brake test specimen, a special glazing 5 is provided in order to allow unimpeded passage of the laser beams 4. The special glazing 5 should have optical properties which have already been explained above. In particular, the special glazing 5 should have an optical glass in order to allow the laser beams 4 to pass unhindered and unchanged The housing 3 is installed inside a test cabin 6 of a brake test stand. In the test cabin 6, a brake 7 is constructed of a corresponding and, in such brake test benches, conventional brake mount 8 as a test object. The brake 7 can be driven by a drive device 9 for applying a brake load in a known manner.

In addition, measuring devices are provided for recording testing and measuring parameters of the brake. Likewise, a ventilation device can be provided with which the brake 7 can be ventilated during test operation and thus cooled. There may also be an air conditioning device which serves to suitably condition the air inside the test cabin 6 (for example, in terms of temperature, humidity, etc.). For purposes of illustration, however, not all components are shown in FIG. 1, which are required for the operation of a brake tester.

Figure 2 shows a console 10 on which the housing 3, not shown in Fig. 2 can be arranged. In particular, the housing 3 can be fastened on the bracket 10 in such a way that it forms a movable or displaceable unit together with the bracket 10.

The console 10 can be moved between a parking position in which the housing 3 with the laser measuring system 1 incorporated therein is not used, and an operating position in which the housing 3 is displaced into the interior of the test cabin of the brake test bench. FIG. 1 shows the housing 3 in the operating position.

For the mobility of the console 10 with the housing 3, a corresponding guide means, e.g. a longitudinal guide may be provided. The guide device can be configured such that the console 10 can be moved with the housing 3 in a parking position, which is located far away from the operating position and thus the cold measuring range.

Claims

claims

1 . Device for a laser measuring system (1), with

a housing (3) at least partially enclosing the laser measuring system (1); in which

- The laser measuring system (1) at least one laser device (2) for generating a directed onto a measuring object (7) laser beam (4);

the laser device (2) is arranged in the housing (3);

the housing (3) at least partially has a temperature-insulating wall; and where

- The housing (3) is vented.

2. Device claim 1, wherein a blower device for ventilating the housing (3) is provided.

3. Device according to one of the preceding claims, wherein the housing (3) in at least part of the wall has a special glazing (5).

4. Device according to one of the preceding claims, wherein the special glazing (5) is an optical glass to let laser beams pass unimpeded and unchanged.

5. Device according to one of the preceding claims, wherein the housing (3) is arranged on a movable bracket (10).

6. Device according to one of the preceding claims, wherein

the device is designed as a device for a brake tester; and where

the laser measuring system (1) has at least one laser device (2) for generating a laser beam (4) directed onto a brake disk of a brake (7) to be tested.

7. Brake test stand with

a brake mount (8) for receiving a brake (7) to be tested; a drive device (9) for applying a braking load to the brake (7);

Measuring devices for detecting testing and measuring parameters of the brake (7); and with a device according to any one of the preceding claims.