EP4048998A1

EP4048998A1 - Test rig and method for testing vehicle tyres

Info

Publication number: EP4048998A1
Application number: EP20793676.6A
Authority: EP
Inventors: Roland BÖSL
Original assignee: ZF Friedrichshafen AG
Current assignee: ZF Friedrichshafen AG
Priority date: 2019-10-22
Filing date: 2020-10-20
Publication date: 2022-08-31
Also published as: US20240060859A1; DE102019216215A1; US12158392B2; CN114556073A; WO2021078734A1

Abstract

The invention relates to a test rig (1) for testing vehicle tyres, comprising a revolving drum (2) on a drum axis (3) and force transducers (4, 5, 6) for measuring a radial force acting on the drum axis (3) and a lateral force acting on the drum axis (3). The test rig (1) according to the invention is characterized in that the test rig (1) comprises three uniaxial force transducers (4, 5, 6), with a first and a second force transducer (4, 5) being disposed to measure a radial force, with a third force transducer (6) being disposed to measure a lateral force, and with the first force transducer (4) being coupled to the third force transducer (6). The invention further relates to a method for testing vehicle tyres.

Description

Test bench and procedure for testing vehicle tires

The present invention relates to a test stand for testing vehicle tires according to the preamble of claim 1 and a method for testing vehicle tires according to the preamble of claim 9.

In the prior art, so-called “Low Speed Uniformity” test stands for determining the synchronization properties of vehicle tires are known. The synchronization properties in low-speed uniformity measurements primarily include the recording and evaluation of forces when the vehicle tire rolls comparatively slowly, for example at around 60 tire revolutions per minute. The commonly used test stands each have two biaxially designed force transducers for a vehicle tire to be tested, each of which can detect forces along two spatial directions. This can lead to an undefined crosstalk of forces between the two force detection channels assigned to the different spatial directions.

A wheel force dynamometer for measuring tire forces is known from DE 10260000 B4, a vehicle wheel being able to be fastened to a wheel axle which is mounted in a hollow shaft via roller bearings. The hollow shaft is hydrostatically supported in a housing that is fixed to the frame. The wheel force dynamometer comprises at least two uniaxial force sensors assigned to the wheel axle, a first force sensor being provided for detecting a wheel load component and a second force sensor being provided for detecting a tangential force component. The force sensors are not coupled to one another.

When measuring tire forces by means of the known test stands, measurement errors can occur which are caused by the design of the test stands.

It is an object of the invention to propose an improved test stand for testing vehicle tires. This object is achieved according to the invention by the test stand for testing vehicle tires according to claim 1. Advantageous refinements and developments of the invention emerge from the dependent claims.

The invention relates to a test stand for testing vehicle tires, comprising a running drum on a drum axis and force transducers for detecting a radial force acting on the drum axis and a lateral force acting on the drum axis. The test stand according to the invention is characterized in that the test stand comprises three uniaxial force transducers, a first and a second force transducer being arranged to detect the radial force, a third force transducer being arranged to detect the lateral force, and the first force transducer and the third force transducer are coupled.

According to the invention, a test stand for testing vehicle tires is therefore provided which comprises a running drum arranged on a drum axle. The drum represents the rolling surface for the vehicle tires to be tested. Radial forces and lateral forces that act between the drum and the vehicle to be tested are recorded by three load cells on the test bench. The three force transducers are three each uniaxial force transducers, ie force transducers that are designed to detect forces exclusively along one spatial direction. This has the advantage, for example, that the force transducer can be calibrated individually. The force sensors can, for example, be force sensors that work according to the piezo principle. Two of the force transducers, namely the first and the second force transducer, are arranged on the test stand or are in contact with the drum axis in such a way that they can detect a radial force acting on the drum axis. The third force transducer is arranged on the test stand or is in contact with the drum axis in such a way that it can detect a lateral force acting on the drum axis. Furthermore, the first force transducer, which can detect a radial force, and the third force transducer, which can detect a lateral force, are coupled to one another, so that when a force is applied to one of the two force transducers, a targeted crosstalk to the other force transducer takes place. When a radial force occurs, which among other things is determined by the first force transducer is grasped, so there is crosstalk to the third force transducer, so that this also detects a force. Conversely, when a lateral force occurs, which is detected by the third force transducer, there is crosstalk to the first force transducer, so that the latter also detects a force.

This has the advantage that a very precise determination of the recorded forces is carried out with only three force transducers, since the coupling of the first force transducer with the third force transducer and the crosstalk set in this way provides additional information about the first and third force transducers detected force is present. This is particularly advantageous for recording the radial force, which is recorded equally by the first and second force transducers. The additional information obtained through the specifically set crosstalk can be used, for example, to computationally compensate for temperature influences on the measurement data of the first force sensor. In the prior art, on the other hand, there is often also crosstalk between force transducers for different force directions or between different force detection directions of a multi-axis force transducer, but this effect is undesirable in the prior art because it occurs in an undefined manner and therefore does not provide any usable information. The test stand according to the invention, however, allows a largely exact Kalibrie tion of each force transducer and a calibration of the crosstalk from the first force transducer to the third force transducer and vice versa.

Since only a single force transducer, namely the third force transducer, is provided for recording the lateral force, the influence of temperature changes on the measurement result with regard to the lateral force can also advantageously be completely eliminated.

It is preferably provided that the first force transducer is assigned to a first axial end of the drum axis or is in contact with a first axial end of the drum axis and that the second force transducer is assigned to a second axial end of the drum axis or with a second axial end of the Drum axis is in contact. Thus, radial forces acting on the running drum can be recorded and recorded particularly reliably. The radial forces usually arise in that the vehicle tire to be tested is brought into contact with the tread drum with a predeterminable application of force in the radial direction, that is to say with the radial force.

According to a preferred embodiment of the invention, it is provided that the first force transducer is in contact with a first axial end of the drum axle via a first coupling link and that the second force transducer is in contact with a second axial end of the drum axle via a second coupling link. This enables a largely optimal introduction of radial forces acting on the drum axis in the first and second force transducers. Due to the preferred, essentially flat cuboid design of the coupling links, torques can also be recorded which arise due to radial forces acting at different positions on the drum axis.

According to a particularly preferred embodiment of the invention, it is provided that the first coupling link is in contact with the first axial end of the drum axis by means of releasable screw connections and that the second coupling arm is in contact with the second axial end of the drum axis by means of releasable screw connections. This results in the advantage that both the first coupling link and the second coupling link can be easily detached from the first axial end and the second axial end, for example, to be exchanged or replaced or to change the test bench structure. Nevertheless, the screw connections guarantee that the first and second coupling links are reliably held at the first and second axial ends, respectively. In addition, a hysteresis which often occurs in the prior art can be avoided as a result, since the screw connections are free of play.

According to a further preferred embodiment of the invention, it is provided that the third force transducer is in contact with the first axial de of the drum axis via a coupling rod. This results in the advantage that the third force transducer can be flexibly adjusted with a predeterminable distance to the drum axis. can be ordered, but is still in contact with the drum axis so that it can detect the lateral force acting on the drum axis.

The coupling rod is preferably arranged at the first axial end of the drum axis coaxially to the drum axis. This arrangement enables a largely optimal transfer of the lateral force acting on the drum axis to the third force transducer.

According to a further particularly preferred embodiment of the invention, it is provided that the third force transducer is in contact with the first coupling link via the coupling rod. This has the advantage that a targeted crosstalk from the force transducer to the third force transducer can be set via the coupling rod and the coupling link, and vice versa.

The coupling link preferably has an opening through which the coupling rod is guided largely free of play. Thus, the coupling stage can be in contact with the first axial end on the one hand and with the coupling link on the other hand without play and thus without the occurrence of hysteresis effects.

According to a further particularly preferred embodiment of the invention, it is provided that the test stand is designed to set a defined over-speaking of the radial force on the third force transducer by means of a predeterminable length and / or a predeterminable rigidity of the coupling rod. This has the advantage that the extent of the crosstalk from the first force transducer to the third force transducer and vice versa can be adjusted in a targeted manner and as required. The shorter and the stiffer the coupling rod, the more pronounced the crosstalk from the first force transducer to the third force transducer and vice versa.

The defined crosstalk is preferably set additionally by a predeterminable length and / or a predeterminable rigidity of the first coupling link. According to a further preferred embodiment of the invention, it is provided that the test stand is designed to set a fall of the running drum by means of first and / or second coupling links of different lengths. Over a length of the coupling arm, in particular over a different length of the first coupling arm and the second coupling arm, a fall of the drum axis relative to the axis of rotation of the vehicle tire to be tested can thus be set in a simple manner. This has the advantage that the vehicle wheel to be tested can be subjected to different test scenarios in a simple manner.

According to a further preferred embodiment of the invention, it is provided that the test stand is designed to set a skew direction of the running drum by offsetting the first and / or the second force transducer. This results in the advantage that a skewing direction of the drum axis with respect to an axis of rotation of the vehicle tire to be tested can be set in a simple manner.

The invention further relates to a method for testing vehicle tires, a radial force acting on a drum axis of a running drum and a lateral force acting on the drum axis of the running drum being detected by means of force transducers. The method according to the invention is characterized in that the radial force is detected by means of a first and a second uniaxial force transducer, the lateral force being detected by means of a third uniaxial force transducer and a defined crosstalk of the radial force to the third force transducer being set. The method according to the invention thus describes a test of a vehicle tire in a test stand according to the invention, which leads to the advantages already described.

According to a preferred embodiment of the invention, it is provided that the first force transducer and / or the second force transducer and / or the third force transducer are individually calibrated. This has the advantage that e.g.

Changes in temperature in the test environment, which also affect the third force transducer, cannot change the test results of the force transducers. The invention is explained by way of example with the aid of embodiments shown in the figures.

Show it:

Fig. 1 exemplarily and schematically a possible embodiment of a test stand according to the invention,

Fig. 2 by way of example and schematically a possible embodiment of a Kop pelungslenkers and

3 an example and schematically shows a drum axis of a test stand according to the invention.

The same objects, functional units and comparable components are denoted by the same reference symbols across the figures. These objects, functional units and comparable components are identical in terms of their technical features, unless the description explicitly or implicitly indicates otherwise.

1 shows, by way of example and schematically, a possible embodiment of a test stand 1 according to the invention. The test stand 1 comprises a running drum 2, which is arranged on a drum axis 3. The drum axis 3 has three translational and three rotational degrees of freedom of movement. A vehicle tire to be tested (not shown in FIG. 1) rolls on a surface of the drum 2 during its test. Furthermore, the test stand 1 comprises a first force transducer 4, a second force transducer 5 and a third force transducer 6. The first force transducer 4 is in contact with a first axial end 3 'of the drum axis 3 via a first coupling link 7 and the second force transducer 5 is in contact with a second coupling link 8 with a second axial end 3 ″ of the drum axis 3 in contact. The first coupling arm 7 is in contact with the first axial end 3 'of the drum axis 3 by means of releasable screw connections and the second coupling arm 8 is in contact with the second axial end 3 ″ of the drum axis 3 by means of releasable screw connections. Since the connection between the first and second coupling links 7, 8 with the first th or second axial end 3 ', 3 "is therefore backlash-free, hysteresis effects that falsify the test can be avoided. Due to the arrangement shown of the first force transducer 4 and the second force transducer 5 at the first axial end 3 ′ and at the second axial end 3 ″, these can each detect a radial force acting on the drum axis 3. Any tangential force that may occur on the drum 2 can also be detected via the flat cuboid-shaped coupling rods 7, 8, in particular in connection with the coupling rod 12 and the third force transducer 6. The third force transducer 6 is arranged at right angles to the first force transducer 4 and is in contact with the first axial end 3 ′ of the drum axis 3 via a coupling rod 12. The third force transducer 6 can thus detect a lateral force acting on the drum axis 3. In addition, the third force transducer 6 is also in contact with the first force transducer 4 via the coupling rod 9 and the first coupling link 7, so that targeted crosstalk from the first force transducer 4 to the third force transducer 6 and vice versa can take place. Due to the arrangement of the third Kraftaufneh mers 6 shown, it can detect a lateral force acting on the drum axis 3. The first force transducer 4, the second force transducer 5 and the third force transducer 6 are each designed as uniaxial force transducers, whereby they are comparatively inexpensive and, above all, can be calibrated comparatively easily. Undesired and undefined crosstalk between force detection channels of a multi-axis force transducer can thus be avoided from the outset. The test stand shown in FIG. 1 is suspended from a support frame 13.

Fig. 2 shows an example and schematically a possible embodiment of a Kop pelungslenkers 7, as it is preferably used for a test stand according to the invention. As can be seen, the coupling link 7 has a series of bores 9 at both axial ends, which are used to receive screws 10 to attach the coupling link by means of screw connections on the force transducer 4 and on the first axial end 3 'of the drum axle 3 (not shown in FIG Fig. 2) to be releasably strengthened. Furthermore, the coupling link 7 has a central opening 11 through which the coupling rod 12 can be passed, in order to enable a targeted talk from the first force transducer 4 to the third force transducer 6 and vice versa. The strength of the crosstalk depends on the length and the rigidity of both the coupling rod 12 and the length and rigidity of the coupling link 7.

Fig. 3 shows by way of example and schematically a drum axis 3 of a test stand according to the invention. The running drum 2 is also indicated by dashed lines. An arrow 14 represents a lateral force acting on the drum axis, which can be detected by the third force transducer via the coupling rod 12. Arrows 15, 15 'and 15 ″ represent radial forces which can be detected by the first and second force transducers 4, 5 via the first and second coupling links 6, 7. Since the arrows 15, 15 ′, 15 ″ or the assigned radial forces act on the drum axis 3 at three different positions, a torque also arises which also acts on the drum axis 3. This torque can in turn be recorded by the first and second force transducers 4, 5 via the first and second coupling links 6, 7 and, due to the coupling of the first coupling link 6 with the coupling rod 12, also by the third force transducer 6. Arrows 16, 16 'represent tangential forces , which can also be detected by the first and second force transducers 4, 5 due to the flat quaderförmi gene formation of the first and second coupling link 6, 7.

Reference symbol

test bench

Drum

Drum axis first axial end of the drum axis second axial end of the drum axis first force transducer second force transducer third force transducer first coupling link second coupling link

drilling

screw

opening

Coupling rod

Support frame

Lateral force, 15 ‘, 15 radial force, 16 'tangential force

Claims

1. Test stand (1) for testing vehicle tires, comprising a running drum (2) on a drum axis (3) and force transducers (4, 5, 6) for detecting a radial force acting on the drum axis (3) and a radial force acting on the drum axis (3) acting lateral force, characterized in that the test stand (1) comprises three uniaxial force transducers (4, 5, 6), a first and a second force transducer (4, 5) being arranged to detect the radial force, with a third force transducer (6) is arranged for detecting the lateral force and wherein the first force transducer (4) and the third force transducer (6) are coupled.

2. Test stand (1) according to claim 1, characterized in that the first force transducer (4) is in contact via a first coupling link (7) with a first axial end (3 ') of the drum axis (3) and that the second force transducer ( 5) is in contact with a second axial end (3 ”) of the drum axle (3) via a second coupling link (8).

3. test stand (1) according to claim 2, characterized in that the first coupling arm (7) by means of releasable screw connections with the first axial end (3 ') of the drum axis (3) is in contact and that the second coupling arm (8) by means of releasable Screw connections with the second axial end (3 ”) of the drum axis (3) is in contact.

4. Test stand (1) according to at least one of claims 1 to 3, characterized in that the third force transducer (6) is in contact with the first axial end (3 ‘) of the drum axis (3) via a coupling rod (12).

5. Test stand (1) according to claim 4, characterized in that the third force transducer (6) is in contact with the first coupling arm (7) via the coupling rod (12).

6. Test stand (1) according to claim 5, characterized in that the test stand (1) is designed to produce a defined crosstalk of the radial force on the third force transducer (6) by means of a predeterminable length and / or a predeterminable rigidity of the coupling rod (12) to be set.

7. Test stand (1) according to at least one of claims 1 to 6, characterized in that the test stand (1) is designed to prevent the running drum (2) from falling by means of first and / or second coupling links (7, 8) of different lengths ).

8. Test stand (1) according to at least one of claims 1 to 7, characterized in that the test stand 81) is designed to shift the first and / or the second force transducer (4, 5) to a skew direction of the drum (2 ).

9. A method for testing vehicle tires, whereby a radial force acting on a drum axis (3) of a running drum (3) and a lateral force acting on the drum axis (3) of the running drum (2) are recorded by means of force transducers (4, 5, 6), characterized in that the radial force is detected by means of a first and a second uniaxial force transducer (4, 5), the lateral force being detected by means of a third uniaxial force transducer (6) and a defined over-speaking of the radial force on the third force transducer (6) is set.

10. The method according to claim 9, characterized in that the first force transducer (4) and / or the second force transducer (5) and / or the third force transducer (6) are individually calibrated.