Loading device for a test bench and test stand

Abstract

Loading device (1) for a test stand (2) for testing a test specimen (17), in particular a transmission or an axle, in particular a switchable transmission, with at least two loading machines (3, 4), and a switchable clutch (8), wherein a first loading machine (3) comprises a first electric motor and a second loading machine (4) comprises a second electric motor, wherein the electric motors are each equipped for a predetermined load range and the load range of the first loading machine (3) differs from the load range of the second loading machine (4) respectively.the other load machines, wherein the load machines (3, 4) can be individually connected to the test specimen (17) and / or connected via a coupling for the transmission of a torque, whereby a test area of ​​the test specimen (17) to be tested is substantially completely covered, wherein the load machines (3, 4) can be connected and disconnected via the switchable coupling (8), wherein the first load machine (3) has a load range with low torques at high speeds and the second load machine (4) has a load range with high torques at low speeds, wherein the first load machine (3) is a high-speed asynchronous motor (7) and the second load machine (4) is a synchronous motor, in particular a low-speed torque motor (6), wherein the second load machine (4) is arranged predominantly within the first load machine (3).

Description

[0001] The invention relates to a loading device for a test bench for testing a test specimen, in particular a gearbox or axle, in particular a switchable gearbox, and to a test bench with a loading device.

[0002] Axles and transmissions are tested in test rigs with regard to their torque and speed characteristics, for example, for later use in a vehicle. In state-of-the-art test rigs, for example, an internal combustion engine or an electric motor is used as a load device, although the electric motor is only economical to operate up to a limited field weakening range.

[0003] DE 199 18 820 A1 discloses a drive machine for generating defined target rotary movements with higher frequency components.

[0004] EP 0 377 950 A2 discloses a drive current source for motor vehicle power transmission test equipment with motor.

[0005] A disadvantage here is that the test benches equipped with this technology are complex, prone to vibration, and require a lot of space.

[0006] The object of the present invention is to provide a loading device for a test bench that enables simple and reliable testing over a wide speed range.

[0007] The problem is solved by a loading device for a test bench for testing a test specimen, in particular a gearbox or axle, especially a switchable gearbox, comprising at least two loading machines and a switchable clutch, wherein a first loading machine comprises a first electric motor and a second loading machine comprises a second electric motor, wherein the electric motors are each equipped for a predetermined load range and the load range of the first loading machine differs from the load range of the second loading machine.the other load machines differ, wherein the load machines can be individually connected to the test specimen and / or connected via a coupling for the transmission of a torque, whereby a test area of ​​the test specimen is substantially completely covered, wherein the load machines can be connected and disconnected via the switchable coupling, wherein the first load machine has a load range with low torques at high speeds and the second load machine has a load range with high torques at low speeds, wherein the first load machine is a high-speed asynchronous motor and the second load machine is a synchronous motor, in particular a low-speed torque motor, wherein the second load machine is arranged predominantly within the first load machine.

[0008] The proposed load device for an axle and / or transmission test bench for driving and braking enables a controllable, low-noise, and energy-efficient test setup. The load device essentially operates as a direct drive. Transmissions with a wide gear ratio range can be tested. By combining the two motors, the drive power, and thus the overall power required for testing, can be significantly reduced. Maintenance-intensive components are eliminated, the footprint is reduced, and unwanted vibrations are minimized. The coordinated selection of load ranges for the load machines, each with different optimization priorities, allows for the coverage of broad torque and speed ranges. The load machine motors can be easily synchronized to the same speed during operation and then mechanically coupled or decoupled.For example, the field weakening range is now approximately 1:16 if, for instance, two motors with field weakening ranges of approximately 1:4 are used. The load device provides drives or brakes that cover the same power P=Mxn from high torques at low speeds to low torques at high speeds.

[0009] It is advantageous if the load machines operate in motor and / or generator mode, depending on the requirements of the test conditions. This allows the load device to be used flexibly, particularly as a drive or braking unit.

[0010] A simple, quiet and stable device exists when the load machines are connected with a rigid coupling and electrical separation is carried out as needed via an associated inverter.

[0011] A very large testing range can be variably covered if the load devices can be connected and disconnected via a switchable coupling.

[0012] It is advantageous if the load machines include a synchronous motor or an asynchronous motor, with the load ranges being predefined for the test area.

[0013] A very wide test range is covered when the first load machine operates with low torques at high speeds and the second load machine operates with high torques at low speeds. The test setup thus achieves optimal load conditions in all test ranges, enabling the testing of various types of transmissions, particularly those in cars and commercial vehicles.

[0014] It is advantageous if the load machines can be connected in parallel and / or in series with the test specimen.

[0015] A compact, space-saving design is achieved when one of the loading machines is arranged inside another loading machine.

[0016] Fast, individually adjustable and safe control is possible if each load machine has its own inverter and, in particular, a pulse width modulator.

[0017] A comprehensive test, particularly in the automotive sector, is possible if the first load machine is a high-speed asynchronous motor and the second load machine is an asynchronous motor with a low corner point.

[0018] It is also advantageous if the first load machine is an asynchronous motor with a high corner point and the second load machine is an asynchronous motor with a low corner point.

[0019] A safe testing of a wide torque / speed range for motor vehicle and commercial vehicle testing is possible if the first load machine is a high-speed asynchronous motor and the second load machine is a synchronous motor, in particular a low-speed torque motor.

[0020] It is also advantageous if the first load machine is a synchronous motor with a high corner point and the second load machine is a synchronous motor, especially a slow-running torque motor. This allows even very powerful commercial vehicle transmissions to be easily tested.

[0021] The problem is also solved by a test rig with a loading device according to any one of claims 1 to 4, wherein the loading device can be used as a drive device for a test specimen and / or as a braking device. The loading machines can be flexibly used as drive devices and braking devices, thus benefiting from the advantages of the various combinations.

[0022] Further features and advantages of the invention will become apparent from the claims and the following description, in which exemplary embodiments of the subject matter of the invention are explained in more detail in conjunction with the drawings.

[0023] They show: Fig. 1 a test bench for testing a test specimen, Fig. 2 a part of a test bench with two load machines and switchable clutch, Fig. 3 a part of a test bench with two load machines and rigid coupling, Fig. 4 a part of a test bench with two load machines and switchable clutch, Fig. 5 a part of a test bench with two load machines and switchable clutch, Fig. 6 a part of a test bench with two load machines and switchable clutch, Fig. 7 a part of a test rig with two load machines and rigid coupling and Fig. 8 a schematic torque-speed diagram.

[0024] Fig. Figure 1 shows a test rig 2, in particular a gearbox test rig, for testing a test specimen 17, in particular a gearbox, with two load machines 3, 4 used as a braking device for braking the test specimen 17 and an electric drive 14 for driving the test specimen 17. The drive 14 is, for example, a controllable electric motor or, for example, a corresponding internal combustion engine. Advantageously, particularly in the case of axle drives, it can, however, comprise a load device according to the invention with two load machines 3, 4, wherein this is in Fig. 1 is not shown. The following Fig. 2 to 7 can be both a drive device 14 and a brake device of the test bench.

[0025] The first load machine 3 preferably comprises a high-speed electric motor, for example, an asynchronous motor. The second load machine 4 preferably comprises a low-speed electric motor with high torque, for example, a synchronous motor, and in particular a torque motor. The electric motors can be used in both motor operation and generator operation, especially for braking. The transition occurs, for example, when a synchronous speed is reached in asynchronous motors.

[0026] Further examples of load-machine combinations are found in the Fig. 2-7 are shown in the example from Fig. In the second load machine 4, a hollow shaft 15 is provided, allowing a shaft 16 of the first load machine 3, located behind the second load machine 4, to extend through the hollow shaft 15 to a coupling, for example, a switchable coupling 8. The two load machines can thus be easily coupled. The second load machine 4 is preferably used at low speeds, while the first load machine 3 is used at higher speeds. Depending on the design of the second load machine 4, it can either run alongside the first load machine 3 without being driven itself, or be mechanically or electrically decoupled by means of the corresponding frequency converter (not shown).Depending on the design, the first load machine 3 can also run alongside the second load machine 4, even at low speeds, with or without a load. This synchronous running is particularly possible when the first load machine 3 is an asynchronous motor and the second load machine 4 is a synchronous or asynchronous motor. To coordinate the torques between the drive 14, the test specimen 17, and the load machines, a torque measurement device 18 is used, for example, to measure the torque delivered by the drive. Furthermore, a measuring device for the rotational speed can also be installed.

[0027] Fig. Figure 2 shows part of a test rig 2 with two load machines 3, 4 and a switchable clutch 8. The first load machine 3 comprises a high-speed asynchronous motor 7, the second load machine 4 comprises a low-speed asynchronous motor 12, which has a transition speed between a speed range with constant torque and a speed range with constant power. The device is particularly advantageous for use in testing motor vehicle transmissions.

[0028] Fig. Figure 3 shows part of a test rig with two load machines 3, 4 and a rigid coupling 10. The first load machine 3 comprises an asynchronous motor 13 with a high corner point, the second load machine 4 comprises an asynchronous motor 12 with a low corner point, each with an exemplary fan 19. The devices from Fig. 2 and Fig. 3 are advantageous to use in the field of motor vehicle testing.

[0029] Fig. Figure 4 shows part of a test rig 2 with two load machines 3, 4 and a switchable clutch 8. The first load machine 3 comprises a high-speed asynchronous motor 7, the second load machine 4 comprises a synchronous motor.

[0030] Fig. Figure 5 shows part of a test rig 2 with two load machines 3, 4 and a switchable clutch 8. The first load machine 3 comprises a high-speed asynchronous motor 7, the second load machine 4 comprises a synchronous motor, in particular a torque motor. The second load machine 4 is arranged predominantly within the first load machine 3, thereby achieving a significantly more compact design while maintaining the full power output of the motors. The devices from Fig. 4 and Fig. 5 are advantageous to use for motor vehicle and / or commercial vehicle testing.

[0031] Fig. Figure 6 shows part of a test rig 2 with two load machines 3, 4 and a switchable clutch 8. The first load machine 3 comprises a high-speed synchronous motor 5, the second load machine 4 comprises a synchronous motor 6 in the form of a torque motor.

[0032] Fig. Figure 7 shows part of a test rig 2 with two load machines 3, 4 and a rigid coupling 10. The first load machine 3 comprises a synchronous motor 11 with a higher corner speed, the second load machine 4 comprises a synchronous motor 6 in the form of a torque motor. During operation at higher speeds, the second load machine 4 with the lower corner speed can be electrically disconnected from the corresponding inverter (not shown) to prevent overvoltages in the inverter. The mechanical coupling can be retained by this method, so that the second load machine 4 rotates even without current at higher speeds. The devices from Fig. 6 and Fig. 7 are advantageous to use in areas of commercial vehicle testing, taking into account the speed ranges.

[0033] Fig. Figure 8 shows a schematic torque-speed diagram of a loading device consisting, by way of example, of two loading machines 3 and 4, although more loading machines can also be used together. The illustrated test range includes, by way of example, the test range of an axle output of a commercial vehicle, whereby for passenger car transmissions the test range would extend up to approximately 10,000 Nm at approximately 10,000 rpm, although larger ranges could also be tested if corresponding loading machines were assembled according to the invention. The torque-speed characteristic 22 of the first loading machine has a high peak, whereby the provided torques are lower than those of the second loading machine, but can be delivered up to a higher speed range. The torque-speed characteristic 23 of the second loading machine has a low peak.The possible torques, according to their absolute values, are higher than those of the first load machine, but can only be provided in a lower speed range. Through the combination of the torque-speed characteristics 22, 23 of the two load machines 3, 4 according to the invention, a significantly larger range can be represented, the torque-speed characteristics of which 21 are in . Fig. Figure 8 shows the entire requirement for covering an exemplary test range 20. Depending on the currently required speed, the load machines can be operated coupled together or separately via the coupling or the inverter. REFERENCE MARK LIST 1 Loading device 2 Test bench 3 first load machine 4 second load machine 5 high-speed synchronous motor 6 Torque motor 7 high-speed asynchronous motor 8 switchable clutches 9 Connection flange 10 rigid coupling 11 Synchronous motor with higher corner point 12 Low-angle asynchronous motor 13 High-angle asynchronous motor 14 Drive device 15 Hollow shaft 16 wave 17 examinees 18 Torque measurement 19 fans 20 Test area 21 Torque-speed behavior 22 Torque-speed behavior 23 Torque-speed behavior

Claims

[1] Loading device (1) for a test stand (2) for testing a test specimen (17), in particular a transmission or an axle, in particular a switchable transmission, with at least two loading machines (3, 4), and a switchable clutch (8), wherein a first loading machine (3) comprises a first electric motor and a second loading machine (4) comprises a second electric motor, wherein the electric motors are each equipped for a predetermined load range and the load range of the first loading machine (3) differs from the load range of the second loading machine (4) respectively.the other load machines, wherein the load machines (3, 4) can be individually connected to the test specimen (17) and / or connected via a coupling for the transmission of a torque, whereby a test area of ​​the test specimen (17) to be tested is substantially completely covered, wherein the load machines (3, 4) can be connected and disconnected via the switchable coupling (8), wherein the first load machine (3) has a load range with low torques at high speeds and the second load machine (4) has a load range with high torques at low speeds, wherein the first load machine (3) is a high-speed asynchronous motor (7) and the second load machine (4) is a synchronous motor, in particular a low-speed torque motor (6), wherein the second load machine (4) is arranged predominantly within the first load machine (3). [2] Loading device (1) according to claim 1, characterized by , that the load machines (3, 4) operate in motor and / or generator mode depending on the requirements of the test conditions. [3] Loading device (1) according to one of claims 1 to 2, characterized by , that the load machines (3, 4) comprise a synchronous motor or an asynchronous motor, wherein the load ranges are each predetermined to complement each other on the test range. [4] Loading device (1) according to one of claims 1 to 3, characterized by , that each load machine (3, 4) has a converter and in particular a pulse width modulator. [5] Test rig (2) with a loading device (1) according to one of the preceding claims 1 to 4, wherein the loading device (1) and / or individual loading machines (3, 4) are to be used as a drive device (14) of a test specimen (17) and / or as a braking device.

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