GB2267157A

GB2267157A - Rolling test bed for motor vehicles

Info

Publication number: GB2267157A
Application number: GB9308309A
Authority: GB
Inventors: Johann Schilcher; Mathias Karrer
Original assignee: Renk GmbH
Current assignee: Renk GmbH
Priority date: 1992-05-21
Filing date: 1993-04-22
Publication date: 1993-11-24
Anticipated expiration: 2013-04-22
Also published as: FR2691539A1; GB9308309D0; GB2267157B; DE4216843A1; FR2691539B1; DE4216843C2

Abstract

A motor vehicle rolling test bed comprises at least one test axle (14), with each test axle having at least two axially spaced test rollers (1) for carrying two motor vehicle wheels of the front axle or the rear axle of a motor vehicle to be tested; a braking and/or driving machine (2) for the braking of the test rollers (1) when driven by the vehicle wheels or for driving the test rollers (1); a distributor gear (4) which comprises at least one planetary gear mechanism; and superimposing drive means (5). A first rotational part of the planetary gear mechanism is drivingly connected to the braking and/or driving machine (2), a second rotational part of the planetary gear mechanism is drivingly connected to one of the two test rollers (1), and a third rotational part of the planetary gear mechanism is drivingly connected to the superimposing drive means (5). The speed of rotation and direction of rotation with which at least one of the test rollers (1) are driven has superimposed thereon the speed of rotation and direction of rotation of the superimposing drive means (5), so that the speed of rotation and the direction of rotation of said at least one test roller is dependent upon both speeds of rotation and on both directions of rotation. <IMAGE>

Description

2267157 ROLLING TEST BED FOR MOTOR VEHICLES This invention relates to a

rolling test bed for motor vehicles. More particularly, it concerns a rolling test bed for motor vehicles comprising at least one test axle, each test axle having at least two axially spaced rollers for carrying two motor vehicle wheels of the front axle or the rear axle of a motor vehicle under test, and a braking and/or driving machine for braking the test rollers driven by the vehicle wheels or for driving the test rollers.

In the case of known rolling test beds for motor vehicles an individual braking and/or driving is machine is required for each rotating test roller.

It is an object of the present invention so to design the rolling test bed for motor vehicles that it is structurally simpler and less costly, yet nevertheless enables all essential motor vehicle travel situations to be simulated with a high quality of control.

This is achieved in accordance with the present invention, in a test bed of the type first referred to above, in that a distributor gear is provided which includes at least one planetary gear mechanism; and superimposing drive means is provided; wherein a first rotational part of the planetary gear mechanism is drivingly connected to the braking and/or driving machine, a second rotational part of the planetary gear mechanism is drivingly connected to one of the two test rollers, and a third rotational part of the planetary gear mechanism is drivingly connected to the superimposing drive means; and wherein the speed of rotation and direction of rotation with which at least one of the test rollers is driven has superimposed thereon the speed of rotation and direction of rotation of the superimposing drive means so that the speed of rotation and direction of rotation of said at least one test roller is dependent upon both speeds of rotation and on both directions of rotation.

By means of the rolling test bed for motor vehicles in accordance with the invention, accurately defined differential speeds of rotation can be introduced both between f ront axle and rear axle and also between left-hand driving side and right-hand driving side in the motor vehicle under test. In this way one has the possibility of simulating travel around bends f or example or monitoring the behaviour of the vehicle under different anti-skid situations.

is In order that the invention may be more fully understood, a number of preferred embodiments of rolling test bed in accordance with the invention will now be described by way of example and with reference to the accompanying drawings. In the drawings:

Fig. 1 is a plan view of a schematically illustrated rolling test bed for motor vehicles in accordance with the invention; Fig. 2 is a more detailed view of one test axle of the rolling test bed shown in Fig. 1; Fig. 3 is a detailed view of a further embodiment of a test axle of a rolling test bed for motor vehicles in accordance with the invention; Fig. 4 is a plan view of a schematically illustrated further embodiment of rolling test bed for motor vehicles in accordance with the invention; and, Fig. 5 is a detailed view of one test axle of the rolling test bed shown in Fig. 4.

The rolling test bed for motor vehicles in accordance with the invention which is illustrated in plan view in Fig. 1 comprises a pair of rolling test plan view in Fig. 1 comprises a pair of rolling test bed units 10 and 12, each with a theoretical test axle 14 and 16. Each rolling test bed unit can be used independently as a rolling test bed. In the embodiment shown in Fig. 1 the two rolling test bed units 10 and 12 together form a single rolling test bed by means of which two axles, for example a front axle and a rear axle, of a motor vehicle can be tested simultaneously.

The two rolling test bed units 10 and 12 are arranged set opposite each other on a foundation and the second rolling test bed unit 12 is adjustable relative to the first test bed unit 10 perpendicular to the longitudinal direction of the axles as indicated by a double-headed arrow 18. In this way the radial spacing of the two test axles 14 and 16 can be matched to the axle spacing between the front axle and rear axle of different motor vehicles.

Since the components in the two rolling test bed units 10 and 12 are identical, only the first rolling test bed unit 10 will be described in detail hereinafter. It comprises two test rollers 1 arranged axially spaced from each other on the test axle 14.

with the appropriate left-hand and right-hand wheels of the motor vehicle to be tested arranged to contact these test rollers; a braking and/or driving machine 2, which is a braking machine or functions as a braking machine when the test rollers 1 are driven by means of the contacting motor vehicle wheels from the engine of the motor vehicle under test, and which is a motor or functions as a motor if the machine 2 is to drive the test rollers 1, so that the test rollers 1 thus drive the motor vehicle wheels which are in contact with them; a torque-transmitting connecting member 3, for example in the form of a clutch; a distributor gear 4 drivingly connected by means of the connecting member 3 comprises at least one planetary gear mechanism and transmits the braking force from the two test rollers 1 to the braking machine 2 or transmits the driving force from the driving machine 2 to the two test rollers 1; and a superimposing drive means 5 by means of which, via the distributor gear 4, additional rotational speed in the direction of rotation or in the opposite direction can be superimposed on the test rollers 1.

The machine 2 can be an electrical machine which functions as a generator for the braking operation and which functions as a motor for the driving operation.

The rolling test bed unit 10 will now be described in detail with reference to Fig. 2. The distributor gear 4 comprises two planetary gear is mechanisms 22 and 24. a first bevel gear mechanism 26 with one small bevel-gear wheel 27 and a large bevel gear wheel 28, and a second bevel gear mechanism 30 having a driving bevel-gear wheel 32 and two driven bevel-gear wheels 33 and 34 located in meshing engagement therewith. The braking and/or driving machine 2 has an input or output shaft 36 which is arranged at right-angles to the test axle 14 and is connected by means of a coupling 38 to a bevel-gear wheel shaft 40, on the end of which remote from the coupling 38 is mounted for conjoint rotation the small bevel-gear wheel 27 of the first bevel gear mechanism 26. The large bevel-gear wheel 28 of the first bevel gear mechanism 26 is seated for conjoint rotation on a distributor shaf t 42 which extends axially up to the first test axle 14 and which at its ends is connected for conjoint rotation to a respective sun wheel 44 of each of the two planetary gear mechanisms 22 and 24.

Planetary gear wheels 46 are rotatably mounted in planetary carriers 48 and are in meshing engagement on the one hand with the sun wheel 44 and on the other hand with a hollow wheel 50. Each planetary carrier 48 is connected for conjoint rotation with a roller axle 54 by means of a coupling 52 The hollow wheels 50 are each connected for conjoint rotation with a respective gearwheel 58 arranged axially adjacent thereto. This gearwheel 58 of the first planetary gear mechanism 22 is in meshing engagement with a gearwheel 60 which is substantially smaller in diameter and which is arranged for conjoint rotation with a first so-called "neutral shaft 621' to which the driven bevel-gear wheel 33 is also connected for conjoint rotation. The gearwheel 58 which is connected for conjoint rotation with the hollow wheel 50 of the second planetary gear mechanism 24 is in engagement with a gearwheel 64 of is substantially smaller diameter,' with the latter being arranged for conjoint rotation with a second so-called neutral shaft 66 to which the second driven bevel-gear wheel 34 is also connected for conjoint rotation.

The superimposing drive means 5 has a take off shaft 67 which is arranged perpendicular to the test axle 14 and is connected by means of a coupling 68 to a shaft 70 on which the driving bevel-gear wheel 32 of the bevel gear mechanism 30 is arranged for conjoint rotation.

The superimposing drive means 5 is preferably a motor, for example an electric motor. The superimposing drive means 5 can however alternatively be a gear mechanism which is driven by means of a connecting gear mechanism (not shown) from the driving machine 2 or from another motor.

If the superimposing drive means 5 holds the two neutral shafts 62 and 64 stationary in a non rotating position, then the two test rollers 1 are driven at a speed and with a torque which is dependent upon the speed and the torque of the braking and/or upon the speed and the torque of the braking and/or driving machine 2 or the speed and the torque of the motor of the vehicle under test, which has its driving wheels on the test rollers 1.

If the superimposing drive means rotates the driving bevel-gear wheel 32 by means of its driving shaft 67 in a particular direction of rotation. then the two neutral shafts 62 and 66 are likewise driven by the driven bevel-gear wheels 33 and 34, but in opposite directions of rotation with reference to one another.

In this way, by means of the planetary gear mechanisms 22 and 24, the speed of rotation of the one test roller 1 is speeded up and the speed of rotation of the other test roller is slowed down. One can even achieve a is reversal of the directions of rotation of the two test rollers 1 in this way. This principle of power superimposition is known with tracked vehicles and there serves for the driving and for the steering of the vehicle tracks. In its application to the rolling test bed this principle has the advantage that even very small differences in speed between the speeds of rotation of the two test rollers 1 of the test axle 14 can be produced very accurately. Thus, one achieves a very high control accuracy for the test bed, which is substantially more accurate than the accuracy with which speeds of rotation and differences in speeds of rotation can be achieved at the braking and/or driving machine 2 or at the superimposing drive means 5. A further advantage is that for the two test rollers 1, only a single braking and/or driving machine 2 is needed. The speeds of rotation and torques are divided by means of the distributor gear 4 uniformly to both test rollers 1, although the transfer could be made wholly to only one or to the other of these two test rollers 1. While, during normal operation, the power the two rollers can be transferred to one roller without having to provide a doubly large braking and/or driving machine 2.

If speed superimpositions are only necessary for one of the two test rollers 1, then only the neutral shaft for the relevant other test roller needs to be omitted. In this case. the first bevel-gear wheel mechanism 30 can also be omitted and the superimposing drive means 5 can be coupled directly to the remaining neutral shaft. Such an arrangement is shown in Fig. 3 and there is provided with the same reference numerals as have been used in Fig. 2. The rolling test bed unit of Fig. 3 is shown rotated through 180' as compared with Fig. 2, and can form a is second rolling test bed unit in relation to the rolling test bed unit of Fig. 2, corresponding to the rolling test bed unit 12 of Fig. 1. Based upon this possibility, in Fig. 3 the rolling test bed unit is indicated by the reference numeral 12 and its test axle by the reference numeral 16. The hollow wheel 50 of the second planetary gear mechanism 22 is connected fixedly to a gear housing 74 and by this means is arranged to be non-rotating. The components provided in Fig. 3 with the same reference numerals as Fig. 1 are formed in the same way and have the same functions as in Fig. 2 and will therefore not be described again in detail.

In the embodiments shown in Figs. 1, 2 and 3 the distributor gear 4 is located in the intermediate space 76 between the two test rollers 1. The braking and/or driving machine 2 and the superimposing drive means 5 are likewise located in this intermediate space 76 or project into it. If because of the distributor gear 4 there is no space left. then these components.

corresponding to the superimposing drive means 5 shown corresponding to the superimposing drive means 5 shown in Fig. 2, can alternatively be located radially outside this intermediate space 76 between the two test rollers 1. This embodiment is very sparing of space if the distance between the test rollers 1 is sufficiently large for the distributor gear 4 to be arranged between these test rollers.

Figs. 4 and 5 show an embodiment in which the test rollers 1 are arranged axially so close to each other that there is no space for the distributor gear 4 to be positioned between them. Consequently. in this embodiment, the distributor gear 4 is divided into two distributor gear part units 4/1 and 4/2. As a consequence, the first planetary gear mechanism 22 with the hollow wheel 50 secured against rotation to the gear housing 74 is located axially on the side of the one test roller 1 which is remote from the other test roller 2. The second planetary gear mechanism 24 with the hollow wheel 50 rotatable by the superimposing gear means 5 is located axially on the outside of the other test roller 1 which is remote from the one test roller 1. No gear components are located between the two test rollers 1. The shaft 42 which connects the sun wheels 44 of the two planetary gear mechanisms 22 and 24 together for conjoint rotation extends through the two test rollers 1 but is not connected to these for conjoint rotation. The one test roller 1 is connected for conjoint rotation by means of couplings 52 to the planetary carrier 48 of the first planetary gear mechanism 22. The other test roller 1 is connected for conjoint rotation by means of other couplings 52 to the planetary carrier 48 of the second planetary gear mechanism 24. The embodiment shown in Fig. 5 functions in the same manner as the embodiment shown in Fig. 3.

Individual parts are therefore not described here again.

The rolling test bed unit of Fig. 5 is there indicated by the reference numeral 12/2. The whole motor vehicle rolling test bed can consist of two such units according to Fig. 5. wherein the other unit is arranged axially with respect to the one test axle 14, corresponding to Fig. 4. The two units 12/2 and 10/1 together form a motor vehicle rolling test bed by means of which one can simultaneously test the front axle and the rear axle of a motor vehicle and also the interaction between the two motor vehicle axles.

In an alternative embodimentr each planetary gear mechanism 22 and 24 could be provided with its own superimposing drive means 5.

Claims

CLAIMS:

1. Rolling test bed for motor vehicles comprising at least one test axle, with each test axle having at least two axially spaced test rollers for carrying two motor vehicle wheels of the front axle or the rear axle of a motor vehicle to be tested; a braking and/or driving machine for the braking of the test rollers when driven by the vehicle wheels or for driving the test rollers; a distributor gear which comprises at least one planetary gear mechanism; and superimposing drive means; wherein a first rotational part of the planetary gear mechanism is drivingly connected to the braking and/or driving machine, a second rotational part of the planetary gear mechanism is drivingly connected to one of the two test rollers, and a third rotational part of the planetary gear mechanism is drivingly connected to the superimposing drive means; and wherein the speed of rotation and direction of rotation with which at least one of the test rollers is driven has superimposed thereon the speed of rotation and direction of rotation of the superimposing drive means, so that the speed of rotation and the direction of rotation of said at least one test roller is dependent upon both speeds of rotation and on both directions of rotation.

2. Rolling test bed according to claim 1, in which a second planetary gear mechanism is provided, a first rotational part of the second planetary gear mechanism is drivingly connected to the braking and/or driving machine, a second rotational part of the second planetary gear mechanism is drivingly connected to a second test roller. and a third part of the second planetary gear mechanism is non-rotatable.

3. Rolling test bed according to claim 1, in which a second planetary gear mechanism is provided, a first rotational part of the second planetary gear mechanism is drivingly connected to the braking and/or driving machine, a second rotational part of the second planetary gear mechanism is drivingly connected to a second test roller, and a third rotational part of the second planetary gear mechanism is drivingly connected by means of the superimposing drive means to a second superimposing drive means.

4. Rolling test bed according to any preceding claim, in which the planetary gear mechanisms are arranged substantially in the axial intermediate space between the two test rollers.

5. Rolling test bed according to one of claims 1 to 3, in which the planetary gear mechanisms are arranged axially outside the two test rollers.

6. Rolling test bed according to one of claims 1 to 4, in which at least two test axles are provided, wherein for each test axle there is provided at least two test rollers. a distributor gear. a braking and/or driving machine and at least one superimposing drive means.

7. Rolling test bed according to any preceding claim, in which at least two test axles are provided and at least one test axle is adjustable relative to the other perpendicular to the longitudinal axes of the axles.

8. Rolling test bed for motor vehicles substantially as hereinbefore described with reference to any one of the Figures of the accompanying drawings.