Patent Application
20230273096
The present invention relates to a revolving drum arrangement, a tire testing stand, and a method for testing vehicle tires.
From the prior art tire testing stands are known, by means of which vehicle tires can be subjected to numerous different testing processes. Known design forms of tire testing stands are, for example, so-termed half-axle testing stands, tire characteristic testing stands, and rolling resistance testing stands. In many different testing methods for vehicle tires forces are simulated, such as those occurring during actual driving operation between the vehicle tires and the road. During this, as a stand-in for the road, a revolving drum is usually used.
In a so-termed balance testing process, for example, the test is carried out without contact with a revolving drum, whereas in contrast, in a so-termed uniformity testing process, the test is carried out with contact between the tire and a revolving drum. Both testing methods can be combined in a single tire testing stand in one testing cycle. For that, for the uniformity test procedure the non-driven rotating drum is accelerated from rest against the tire acting as a friction wheel. Then, after the test the rotating drum coasts down to rest.
In the known tire testing stands, to avoid tire abrasion or tire wear and the resulting pollution, it is usual to bring the vehicle tires to be tested and the rotating drum into contact only when their rotation speeds are identical.
In this connection DE 10 2006 011 703 A1 describes a testing device for a vehicle wheel with a wheel test spindle which supports the wheel, and a tire fitted onto the wheel while they rotate. A road simulation drum with an outer surface is in contact with the tire during the test.
DE 299 23 728 U1 describes a revolving drum for a vehicle-testing or tire-testing stand, wherein a segment of the running surface can be removed and an obstacle with negative radial elevation can be used. A flat-machined carrier plate is welded into the outer surface of the cylindrical revolving drum, onto which various obstacles and the removable original running surface section can be screwed.
From DE 10 2017 217 816 A1 a revolving drum arrangement with a drum body for a testing stand is known. The drum body is arranged on a base frame and can be driven by a friction wheel drive.
However, the known tire testing stands share the disadvantage that revolving drums of the known tire testing stands are as a rule not driven and yet, owing to their diameter typically of more than one meter and their metallic structure, they have a comparatively large moment of inertia. Since after each test run the revolving drums coast to a stop, correspondingly long waiting times are needed in order to reach a synchronization of the running speed of the revolving drum with the vehicle tire to be tested. But such tedious synchronization processes influence the cycle time of the tire testing stand unfavorably. Yet, if a drive for accelerating or braking the revolving drum is provided, then during a test cycle this has an adverse effect on the rolling behavior of the revolving drum and thus also on the rolling behavior of the vehicle tire to be tested.
A purpose of the present invention is to propose an improved revolving drum arrangement for a tire testing stand.
According to the invention, this objective is achieved by the revolving drum arrangement for a tire testing stand according to claim 1. Advantageous design features and further developments of the invention emerge from the dependent claims.
The invention relates to a revolving drum arrangement for a tire testing stand having a drum body and a friction wheel drive, wherein on its outer circumference the drum body has a running surface for making contact with a vehicle tire and is arranged to rotate about its running axle, and wherein the friction wheel drive is designed to drive the drum body when it is in contact with the drum body. The revolving drum arrangement according to the invention is distinguished in that the friction wheel drive is arranged on a friction wheel carriage, such that the friction wheel carriage is designed to move the friction wheel drive along an infeed direction so that the friction wheel drive can be brought into contact with the drum body.
Thus, a revolving drum arrangement is provided which is suitable for use in a tire testing stand. The revolving drum arrangement serves in particular for road simulations for a vehicle tire.
For that purpose, the revolving drum arrangement comprises a drum body, which in the course of road simulations represents the running surface for the vehicle tire. Preferably, the drum body has a cylindrical shape and its outer surface is designed as the running surface for the vehicle tires. Advantageously, the running surface is formed by the cylindrical outer envelope surface of the drum body.
The drum body is arranged in the revolving drum arrangement in such manner that it can rotate about its running axle. Advantageously, the revolving drum arrangement comprises for example a base frame on which the drum body is arranged so that it can rotate. The running axle of the cylindrical drum body is preferably identical with its longitudinal axis.
Furthermore, the revolving drum arrangement comprises a friction wheel drive which can drive the drum body and in particular also can brake the drum body. For that purpose, the friction wheel drive has a friction wheel which allows a frictional or force-locking connection to the drum body when it is in contact with the drum body, in particular in contact with the running surface of the drum body.
According to the invention, it is now provided that the friction wheel drive is arranged on a friction wheel carriage which is part of the revolving drum arrangement, this friction wheel carriage being designed to move the friction wheel drive along an infeed direction so that the friction wheel drive can be bought into contact with the drum body. For that purpose, the friction wheel carriage, for example, can be arranged on rails provided for the purpose.
This advantageously enables the friction wheel drive to be brought into contact with the drum body as necessary, in particular into contact with the running surface. Likewise, the friction wheel drive can be withdrawn again from the drum body or its running surface when no further drive torque or braking torque on the drum body is required.
In a typical tire testing cycle, various speed intervals are driven through and thereby the rolling behavior of the vehicle tire to be tested is investigated. To be able more rapidly to reach the necessary synchronization of the running speed of the revolving drum with that of the tire being tested when, for example, the tire to be tested is changed, it is advantageous to adjust the speed of the drum body by means of the friction wheel drive while the next tire to be tested is being fitted and prepared for the testing process.
During the actual testing process the friction wheel drive can then be withdrawn again from the drum body, so that the rolling behavior of the vehicle tire is not indirectly influenced by the friction wheel drive.
In that way qualitatively high-grade test data can be obtained in comparatively short cycle times.
In the context of the invention the term “running speed” is understood to be that translational speed which a cylindrical body such as the drum body or the vehicle tire would have if it were actually rolling over a subsurface at the rotation speed set in each case. Since as a rule the revolving drum has a substantially larger diameter than the vehicle tire, at correspondingly lower rotation speeds it already reaches the same running speed as a vehicle tire rolling against it.
According to a preferred embodiment of the invention it is provided that the friction wheel drive can be brought into contact with the outer circumference of the running surface or into contact with an inner circumference of the running surface. Depending on whether the friction wheel drive can be brought into contact with the outer circumference or the inner circumference of the running surface, the friction wheel drive with the friction wheel carriage is advantageously arranged outside or inside the drum body. An arrangement outside the drum body offers the advantage of comparatively good accessibility and simple assembly, whereas an arrangement inside the drum body makes for a comparatively space-saving and compact structure of the revolving drum arrangement.
According to a further preferred embodiment of the invention it is provided that the friction wheel drive comprises a friction wheel motor, the said motor being designed to set and adjust a rotation speed of the friction wheel drive. The friction wheel motor is preferably an electric motor and drives the friction wheel directly, or indirectly by way of a gear ratio step.
Preferably, it is provided that the friction wheel drive also comprises a brake that can reduce the rotation speed of the friction wheel drive. The brake can be, for example, a mechanical friction brake, or a no-contact eddy-current brake.
According to a further preferred embodiment of the invention, it is provided that the friction wheel drive is designed to set or adjust a rotation speed of the drum body about its running axle. This means that the friction wheel drive, particularly in relation to its mechanical performance, i.e. torque and rotation speed, but also in relation to its ability to form a driving connection to the drum body, is suitable for setting the rotation speed of the drum body about its running axle. Thus, by means of the friction wheel drive the drum body can be adjusted to the desired rotation speed in a simple manner. The electric motor in this case enables the rotation speed of the drum body not only to be increased, but also to be reduced.
In a further preferred embodiment of the invention, it is provided that the drum body is made of metal. This makes for great durability and only little wear, in particular of the running surface of the drum body, even when used continually and under high loads. However, by virtue of its metallic structure the drum body has a comparatively high moment of inertia, which in turn would result in comparatively tedious acceleration and braking processes were it not, in particular, for the friction wheel drive provided in accordance with the invention.
According to a further preferred embodiment of the invention, it is provided that the outer circumference has a diameter of at least 1.5 m and the running surface a width of at least 0.5 m. Thus, the revolving drum arrangement is particularly suitable for a tire testing stand for testing utility vehicle tires.
The invention also relates to a tire testing stand for testing vehicle tires. The tire testing stand according to the invention is distinguished in that the tire testing stand comprises a revolving drum arrangement according to the invention. Thus, the advantages already mentioned in connection with the revolving drum arrangement according to the invention also apply to the tire testing stand according to the invention.
According to a preferred embodiment of the invention, it is provided that the tire testing stand also comprises a wheel spindle for holding a vehicle tire. In that way, a vehicle tire to be tested can be fitted, tested and set aside again while maintaining comparatively short cycle times.
In the context of the invention the vehicle tire itself is not part of the tire testing stand.
According to a further preferred embodiment of the invention, it is provided that the tire testing stand also comprises a drum carriage such that the revolving drum arrangement is arranged on the drum carriage and the drum carriage is designed to bring a running surface of the revolving drum arrangement into contact with the vehicle tire. This has the advantage that by means of the drum carriage the revolving drum arrangement can be moved toward the vehicle tire which is fitted on the tire spindle and is to be tested, and the running surface of the revolving drum can be brought into contact with the vehicle tire. Likewise, at the end of the testing process the revolving drum arrangement can be withdrawn again from the vehicle tire by means of the drum carriage. Thus, a desired rotation speed of the revolving drum can be set before the revolving drum comes into contact with the vehicle tire.
In a further preferred embodiment of the invention, it is provided that the tire testing stand also comprises a spindle motor, which is designed to set a rotation speed of the wheel spindle. Thus, for example, during the testing process an acceleration behavior and a deceleration behavior of the vehicle tire can be tested. The spindle motor is preferably an electric motor.
According to a further preferred embodiment of the invention, it is provided that the tire testing stand comprises synchronization means, the synchronization means being designed to synchronize a running speed of the vehicle tire and a running speed of the drum body of the revolving drum arrangement. Thus, the synchronization means match the running speed of the drum body and the running speed of the vehicle tire so that they are identical and the revolving drum with its running path can be brought into contact with the vehicle tire in order to carry out a testing process.
The synchronization means preferably comprise rotation speed measurement means for the tire spindle, for the revolving drum and in particular also for friction wheel drive. In addition, the synchronization means advantageously comprise calculation means for calculating a running speed of the revolving drum and the vehicle tire, with reference to the rotation speeds measured.
In a further preferred embodiment of the invention it is provided that an infeed axis of the drum carriage is parallel to an infeed axis of a friction wheel carriage of the revolving drum arrangement.
Finally, the invention also relates to a method for testing vehicle tires using a tire testing stand according to the invention, the said method comprising the following steps:
The distinguishing feature of the method according to the invention is that the friction wheel drive is withdrawn from the drum body by a friction wheel carriage before the vehicle tire test is carried out. Thus, the method according to the invention enables a vehicle tire test to be carried out on a tire testing stand according to the invention, making full use of the advantages already described.
In the context of the invention, “accelerating the rotation speed of the vehicle tire” and “accelerating the rotation speed of the drum body” should be understood to mean not only a positive acceleration in the sense of a rotation speed increase, but also a negative acceleration in the sense of a rotation speed reduction.
Below, an example of the invention is explained with reference to embodiments illustrated in the FIGURES, which show:
The same objects, functional units and comparable components are denoted by the same indexes in all the figures. These objects, functional units and comparable components are of identical design as regards their technical features, unless explicitly stated otherwise in the description or implied therein.
On the wheel spindle 3 is arranged, for example, a vehicle tire 4, in this case a utility vehicle tire 4. The vehicle tire 4 is not part of the testing stand 3 and serves in
The revolving drum arrangement 2 comprises a drum body 5 and a friction wheel drive 6, these being arranged on a drum carriage 7 of the revolving drum arrangement 2. On its outer circumference 9 the drum body 5 has a running surface 9 for making contact with the vehicle tire 4 and is arranged to rotate about its running axle.
The drum carriage 7 can be moved along rails 8 so that it can bring the drum body 5 into contact with the vehicle tire 4.
The friction wheel drive 6 can be driven by a friction wheel electric motor (not shown in
As an example, the tire testing stand 1 is a testing stand 1 for utility vehicle tires with a drum body 5 made of metal. For example, the drum body 5 has a diameter of 1.6 m and the running surface 9 has a width of 0.6 m.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10 2020 209 547.7 | Jul 2020 | DE | national |
This application claims the benefit under 35 U.S.C. § 371 as a U.S. National Phase Application of application no. PCT/EP2021/070860, filed on 26 Jul. 2021, which claims benefit of German Patent Application no. 10 2020 209 547.7 filed 29 Jul. 2020, the contents of which are hereby incorporated herein by reference in their entireties.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/EP2021/070860 | 7/26/2021 | WO |
