DE102020214884B4 - Drive unit for a powertrain test bench and powertrain test bench - Google Patents

Abstract

Drive unit (2) for a drive train test stand for testing electrical motor vehicle drive trains, comprising an electric motor (1) with a housing (3) and a support device (4) for supporting the electric motor (1), the housing (3) having a front end shield ( 5) of the electromor (1) comprising a mechanical front yoke (6) integrally connected and a mechanical rear yoke integral with a rear bearing plate of the electromor (1), the front yoke (5) and the rear yoke being located respectively above the electric motor ( 1) stretching in both lateral directions from the electric motor (1), the support device (4) supporting the electric motor (1) via the front yoke (6) and the rear yoke, so that free spaces are formed below and to the side of the electric motor (1), and wherein the drive unit (2) further comprises at least one support module (8, 8', 8'', 8''') which additionally supports the housing (3) against the supporting device (4), characterized thereby net, that the at least one support module (8, 8', 8'', 8''') is designed as a vibration damper and that the at least one support module (8, 8', 8'', 8''') is screwed by means of a screw thread a spring or can be clamped by insertable wedges.

Description

The invention relates to a drive unit for a drive train test stand for testing electric motor vehicle drive trains according to the preamble of claim 1 and a corresponding drive train test stand for testing electric motor vehicle drive trains.

Transmission test benches or drive train test benches for testing motor vehicle transmissions or complete motor vehicle drive trains are known from the prior art. Such test benches are used on the one hand to detect malfunctions in the drive train immediately after they have been manufactured as part of a so-called end-of-line test using a series of load tests. Typical malfunctions are caused, for example, by components that are subject to play, e.g. B. gears, synchronizing rings, synchronizing bodies, multi-plate clutch disks and shafts, which can be deflected or even excited to vibrate. As part of the functional testing, the acoustic behavior and the shift quality are usually also checked. On the other hand, however, such test benches are also used in the development for the continuous improvement of motor vehicle drive trains. Such drive train test benches usually include an electric motor as the drive.

In this context, describes the DE 10 2012 018 359 A1 a transmission test stand with a first servomotor serving as a drive motor and a second servomotor serving as a brake motor. The drive motor is connected via a clutch to the drive shaft of a motor vehicle transmission to be tested and its speed is controlled by a PC, with any speed curves being simulatable. The brake motor is connected to an output shaft of the motor vehicle transmission to be tested via a further clutch. The speed of the second motor is also controlled via the PC. The speed curves simulated by the PC are speed curves measured in real driving tests.

In addition, electric motor vehicle drive trains are increasingly appearing in the prior art, the structure of which differs in various respects from that of a drive train driven by an internal combustion engine. In particular, an electric motor vehicle drive train must be designed for significantly higher input speeds, which places special demands on the noise behavior at very high speeds and, in particular, vibration damping. Accordingly, a drive train test stand for an electric motor vehicle drive train must be able to provide high speeds and also have a drive unit that generates only minimal mechanical vibrations or introduces them into the test object even at high and very high speeds. Another important criterion for an electric powertrain test bench is the ability to test electric, axis-parallel axle drives, in which at least one shaft must be guided below or close to the side of the drive motor of the test bench. Accordingly, sufficient free installation space must be provided on the side and below the drive motor of the drive unit.

From the DE 19 15 896 A1 an electrical machine is known in which the stator laminations are stamped in such a way that a supporting structure of the electrical machine or at least parts thereof are also obtained from the same sheet metal. The electric machine can be supported by this support structure in such a way that there is a free space underneath the electric machine.

From the CN 1 10 635 612 B a high-speed motor for electric vehicles is known. The motor is placed in a housing via a bearing and surrounded by sound-absorbing material. The housing is connected via spring shock absorbers to support struts which support the housing.

The DE 10 2016 224 138 A1 describes an electric motor for a drive unit of an electric powertrain test bench in which the housing can be supported via a mechanical front yoke and a mechanical back yoke. Starting from the upper area of the housing, the yoke arms extend radially to the side, so that there are free spaces below and to the side of the motor, through which, for example, output shafts of a test specimen can be routed past the electric motor. The front yoke is designed in one piece with a front bearing plate of the electric motor and the rear yoke is designed in one piece with a rear bearing plate of the electric motor. Since the bearings of the motor shaft are connected very firmly and rigidly to the suspension of the electric motor, there is an excellent damping effect on vibrations that occur, especially at very high motor speeds, as are required for testing electric motor vehicle drive trains.

The CN 2 09 627 127 U describes a centrifuge motor arranged on a first plate, the first plate being connected to a second plate via three vibration dampers. This can prevent the occurrence of resonance vibrations in the centrifugal motor.

The U.S. 2005/0 046 733 A1 shows a scanner motor assembly with a scanner motor for rotating a polygon mirror, a frame with a plurality of support members that support the scanner motor, a plurality of anti-vibration members that are arranged between the scanner motor and the frame to prevent transmission of vibrations of the motor to the frame to prevent, and a variety of fasteners that attach the scanner motor to the frame motor.

However, the known drive train test benches are disadvantageous in that they still tend to a certain extent to the occurrence of vibrations from the electric motor at increasingly high speeds, which are then transmitted to the test specimen and can adversely affect the test result.

It is an object of the present invention to propose an improved drive unit for a drive train test stand for testing electrical motor vehicle drive trains.

According to the invention, this object is achieved by the drive unit for a drive train test stand for testing electrical motor vehicle drive trains according to claim 1 . Advantageous configurations result from the dependent claims.

The invention relates to a drive unit for a drive train test bench for testing electrical motor vehicle drive trains, comprising an electric motor with a housing and a support device for supporting the electric motor, the housing having a front end plate of the electromor connected in one piece with a mechanical front yoke and a rear end plate of the electromor integrally connected mechanical rear yoke, wherein the front yoke and the rear yoke each extend above the electric motor in both lateral directions from the electric motor, and wherein the support device supports the electric motor via the front yoke and the rear yoke, so that there are clearances below and to the side of the electric motor are formed. The drive unit according to the invention is characterized in that the drive unit also includes at least one support module, which additionally supports the housing against the carrying device.

The invention thus relates to a drive unit for a drive train test stand, the drive train test stand being designed for testing electrical motor vehicle drive trains. The test object to be tested is therefore an electric motor vehicle drive train. Electric motor vehicle drive trains differ from conventionally driven motor vehicle drive trains in particular by the much higher input speed, which in turn places comparatively higher demands on the vibration damping or rigidity of the motor vehicle drive train and on the noise behavior of the motor vehicle drive train.

In addition to the drive unit, such a drive train test stand typically also includes a holder for holding the test specimen and, if necessary, one or more drive units, which can generate an adjustable load on the test specimen relative to the drive unit.

The drive unit provided according to the invention in turn comprises an electric motor with a housing, with the electric motor being able to apply an input speed and an input torque to the test object in accordance with a control of the electric motor. The housing consists of a casing body and a front and a rear bearing plate, with the front and the rear bearing plate closing off the casing body axially. The front and rear end shields are therefore part of the housing. The front end shield also holds a front bearing of the motor shaft and the rear end shield holds a rear bearing of the motor shaft accordingly. The motor shaft is therefore supported on the front or rear end shield via the front or rear bearing.

The front end shield is designed in one piece with a front mechanical yoke, which is located above the electric motor and stretches symmetrically in both lateral directions from the electric motor. Likewise, the rear end shield is formed in one piece with a rear mechanical yoke, which is also located above the electric motor and also extends symmetrically in both lateral directions from the electric motor. This design has the advantage that the connection of the front and rear yoke to the electric motor is designed to be particularly stiff, which promotes improved vibration damping and, associated with this, improved accuracy in testing the test object.

The support device serves to support the electric motor via the front and rear yokes and has suitable bearing surfaces for this purpose. Advantageously, the front and the rear yoke can be screwed or clamped to the supporting device on the bearing surfaces, so that a particularly strong and particularly vibration-damping connection results. It is also preferably provided that the support device is at least partially made of mineral concrete, polymer concrete or a similar, highly damping material Material is, which is also very good for vibration damping. Such a suitable material is known, for example, under the protected designation "Hydropol". The carrying device particularly preferably also has a metal skeleton which is surrounded, in particular cast, by the vibration-damping material. Thus, the support device itself is designed to be vibration-damping. Due to the very high speeds typical of electric motors compared to internal combustion engines, the vibration damping of the drive unit according to the invention is of great importance, since otherwise vibrations generated by the electric motor are propagated to the test object and have an unfavorable effect on its test behavior.

The front and the rear yoke of the electric motor are preferably made of metal and are solid, in particular made of steel or a steel alloy. Alternatively, preferably, the front and rear yokes are formed of aluminum or an aluminum alloy. The front and rear yokes are further configured to support the electric motor on the support. Like the carrying device, the front and rear yoke particularly preferably consist of a metallic skeleton surrounded by mineral concrete, polymer concrete or a similar, highly damping material, in particular “hydropole”.

Because the electric motor is supported on the support device via the front and rear yoke, in particular via the laterally outer ends of the front and rear yoke on the support device, comparatively large free spaces are created below and to the side of the electric motor, through which, for example, output shafts of the test specimen can be guided past the electric motor. Due to their design as axle drives or as so-called axle-parallel drives with an electric drive arranged parallel to the axle, this is a requirement that frequently occurs in connection with the testing of electric motor vehicle drive trains. In the case of electric motor vehicle drive trains constructed parallel to the axis, the output shaft is arranged outside of the electric drive, namely parallel to the axis of the motor shaft of the electric drive.

According to the invention, it is now provided that the drive unit further comprises at least one support module, which additionally supports the housing against the carrying device. By additionally supporting the electric motor via its housing against the support device, the support module enables further stiffening of the drive unit and thus more precise testing of the test specimen, especially at very high speeds and at speeds of electric motor vehicle drive trains that will continue to increase in the future.

Provision is preferably made for the drive unit to be designed in such a way that a first natural frequency of the drive unit is above the first rotational order of the electric motor. At an engine speed of 15,000 rpm, the natural frequency of the drive unit is above approx. 350 Hz. This has proven to be particularly suitable for testing high-speed electric motor vehicle drive trains.

According to the invention, it is provided that the at least one support module is designed as a vibration damper. For this purpose, the at least one support module is advantageously designed as a cylinder-piston module, which comprises a damping medium in the cylinder that flows past the piston or through the piston. Thus, despite the high rigidity of the drive unit, any vibrations that do occur can be particularly effectively damped.

According to the invention, it is also provided that the at least one support module can be clamped by means of a screw thread, by means of a spring or by means of wedges that can be inserted. This results in the advantage that the at least one support module stiffens the electric motor against the support device with an adjustable or predetermined prestressing force. If the screw thread is used, the length of the at least one support module can be adjusted by screwing in or unscrewing a foot of the at least one support module, so that the at least one support module can be arranged between the electric motor and the carrying device and then the foot of the at least one support module can be unscrewed by means of the screw thread so far that the at least one support module has the desired prestressing force between the electric motor and the supporting device and is held due to the prestressing force between the electric motor and the supporting device. If the spring is used, the prestressing force is predetermined by the strength of the spring, which wants to urge the foot of the at least one support module into an end position. By compressing the spring, the at least one support module can be arranged between the electric motor and the support device. When the spring is no longer compressed, the at least one support module is clamped between the electric motor and the support device. The spring is preferably a spiral spring. If the at least one support module by insertable wedges between the housing and the Carrying device is to be clamped, a required number of wedges can be inserted, for example, in a receptacle provided for this purpose of the at least one support module, so that axial ends of the at least one support module are spread apart. It is also conceivable and preferred to arrange the wedges between the housing and the at least one support module or between the carrying device and the at least one support module in order to achieve firm clamping in this way. In both cases the wedges can be placed, for example, by means of short and well-aimed blows with a hammer or a similar tool.

According to a further preferred embodiment of the invention, it is provided that the at least one support module can be screwed to the housing and the carrying device by means of threaded bores provided for this purpose. The threaded holes are advantageously located in the housing and in the support device. The at least one support module can thus be held reliably in the position provided for this purpose and is secured against loosening or slipping, in particular even when vibrations occur.

According to a further preferred embodiment of the invention, it is provided that the at least one support module bears against the front or the rear bearing plate. Since the bearings of the motor shaft are held by the front and rear bearing plates of the electric motor and vibrations caused by the rotation of the motor shaft are introduced directly into the bearings, the vibration damping of the electric motor can be improved particularly efficiently by the electric motor against the support device in the area of the bearing plates is further stiffened. In addition to the already mentioned advantageous increase in stiffening due to the at least one support module, arranging the at least one support module on the front or rear bearing plate has the additional advantage that the power flow of the mechanical vibrations of the electric motor is idealized in such a way that these are transmitted via the at least a support module can be derived directly from the respective storage, i.e. the place where the vibration occurs, into the carrying device. This leads to an additional improvement in the vibration behavior.

According to a further preferred embodiment of the invention, it is provided that the at least one support module rests against the housing either exactly horizontally or exactly vertically. This has proven to be advantageous with regard to the ability to support the at least one support module against the support device, since this is usually dominated by horizontal and vertical surfaces. The at least one support module can thus generate a comparatively greater prestressing force between the electric motor and the support device due to the better supportability, which in turn contributes to a correspondingly greater improvement in the rigidity of the drive unit according to the invention.

According to a further preferred embodiment of the invention, it is provided that at least one support module rests against the front or the rear bearing plate. The improvements mentioned in the rigidity and vibration damping of the drive unit according to the invention are thus achieved at both axial ends of the electric motor, which in total leads to even greater rigidity and even better vibration damping. Another great advantage that results from the application of more than just one support module on the front bearing plate and on the rear bearing plate is the fact that pressing forces acting on the housing from the support modules do not lead to an elastic deformation of the housing, since the support modules are preferably arranged on the front or on the rear bearing plate in such a way that the pressing forces emanating from them are directed in opposite directions and thus no resulting bending force acts on the housing. The housing thus remains essentially unstressed, so that even with very high pressing forces, there is no misalignment of the front bearing with respect to the rear bearing, which would result in increased friction, increased wear and also increased occurrence of vibrations. Due to the very high speeds of the electric motor, it is necessary to align the two bearings to one another with an accuracy of a few micrometers.

According to a further preferred embodiment of the invention, it is provided that two support modules rest against the front and the rear bearing plate. This leads to a further improvement in the rigidity of the drive unit and a further improvement in the vibration damping of the drive unit.

According to a further preferred embodiment of the invention, it is provided that three support modules rest against the front and the rear bearing plate. This leads to an even further improvement in the rigidity of the drive unit and to an even further improvement in the vibration damping of the drive unit.

According to a further preferred embodiment of the invention, it is provided that the drive unit also has a terminal box includes, wherein the terminal box rests flush on a top of the front yoke and on a top of the rear yoke and wherein the terminal box has additional stiffening struts. The use of a so-called. However, since the terminal box contains additional stiffening struts, which are in particular solid and made of steel and rest flush on the tops of the yokes, there is an additional vibration-damping effect and a further stiffening of the drive unit.

According to a further preferred embodiment of the invention, provision is made for the front yoke and/or the rear yoke to have fluid bearing cooling. The fluid bearing cooling can effectively dissipate waste heat generated in the front and rear bearing of the motor shaft and thus reduce the wear of the respective bearing. The fluid used for cooling is preferably a liquid, for example water or an oil.

According to a further preferred embodiment of the invention, it is provided that the housing has a radial diameter of less than 270 mm. This results in the advantage that the electric motor is designed to be comparatively slim in order to ensure as much free space as possible below and to the side of the electric motor. In particular, this further benefits the testing of electric motor vehicle drive trains that are constructed with parallel axes, above all without an additional deflection gear.

According to a further preferred embodiment of the invention, it is provided that the electric motor is designed to reach speeds of up to 25,000 rpm. The electric motor is particularly preferably designed to achieve speeds of more than 15,000 rpm and up to 25,000 rpm, and the electric motor is very particularly preferably designed to achieve speeds of more than 20,000 rpm and up to 25,000 rpm . Such speeds correspond to the speeds that are generated during operation of an electric motor vehicle drive by its electric drive, ie by its electric motor. This enables a realistic test of the electric motor vehicle drive.

The electric motor can also be designed to achieve speeds of more than 25,000 rpm.

The invention further relates to a drive train test stand for testing electric motor vehicle drive trains, comprising a drive unit according to the invention. Thus, the advantages mentioned in connection with the drive unit according to the invention also result for the drive train test stand according to the invention.

The invention is explained below by way of example using the embodiments shown in the figures.

• 1 beispielhaft und schematisch eine mögliche Ausbildungsform einer erfindungsgemäßen Antriebseinheit für einen Antriebsstrangprüfstand zum Prüfen elektrischer Kraftfahrzeugantriebsstränge,
• 2 beispielhaft und schematisch eine weitere mögliche Ausbildungsform einer erfindungsgemäßen Antriebseinheit,
• 3 beispielhaft und schematisch eine nochmals weitere mögliche Ausbildungsform einer erfindungsgemäßen Antriebseinheit und
• 4 beispielhaft und schematisch eine nochmals weitere mögliche Ausbildungsform einer erfindungsgemäßen Antriebseinheit.

Show it:

• 1 exemplary and schematic of a possible embodiment of a drive unit according to the invention for a drive train test bench for testing electric motor vehicle drive trains,
• 2 exemplary and schematic of a further possible embodiment of a drive unit according to the invention,
• 3 by way of example and schematically another possible embodiment of a drive unit according to the invention and
• 4 by way of example and diagrammatically another possible embodiment of a drive unit according to the invention.

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

1 shows a possible embodiment of a drive unit 2 according to the invention for an in 1 drive train test bench, not shown, for testing electric motor vehicle drive trains. The drive unit 1 comprises an electric motor 1 with a housing 3 and a support device 4 for supporting the electric motor 1. The housing 3 in turn comprises a mechanical front yoke 6 which is integrally connected to a front bearing plate 5 of the electromotor 1 and a mechanical front yoke 6 which is connected to a rear bearing plate (not shown in the perspective of 1 ) of the electromor 1 integrally connected mechanical rear yoke (also not shown in the perspective of 1 ). As can be seen, the front yoke 6 extends above the electric motor 1 in both lateral directions from the electric motor 1 . Likewise, that also stretches in 1 not shown rear yoke above the electric motor 1 in both lateral directions from the electric motor 1. With the axial ends of the front Yoke 6 and the rear yoke is the electric motor 1 on the support device 4, so that the support device 4 carries the electric motor 1 so. According to the example, the axial ends of the front yoke 6 and the rear yoke are connected to the supporting device 4 via screw connections. By the electric motor 1 as in 1 is carried by the carrying device 4 via the front yoke 6 and the rear yoke, free spaces are formed below the electric motor 1 and on both sides of the electric motor 1, through which, for example, an output shaft of a test specimen (not shown in 1 ) can be guided past the electric motor. Also visible is the terminal box 7 which, for example, rests flush on an upper side of the front yoke 6 and on an upper side of the rear yoke and has additional stiffening struts inside.

Also seen in 1 is a support module 8, which rests exactly horizontally on the front bearing plate 5. By means of a screw thread of the support module 8, the support module 8 can be clamped between the electric motor 1 and the support device 4 with a preload force that can be adjusted via the screw thread. This further increases the rigidity of the drive unit 2 . Since the support module 8 can be removed and repositioned on the drive unit 2 relatively easily, it can be arranged in a free space below or to the side of the electric motor 1, depending on the individual installation space requirements of the test specimen to be tested, which space is not required by the test specimen .

According to the invention, the support module 8 is designed as a vibration damper, consisting of a cylinder-piston module and a damping medium in the cylinder.

2 shows an example and schematically another possible embodiment of a drive unit according to the invention 2. The embodiment of 2 differs from the in 1 exemplary embodiment shown in that a further support module 8 'is provided. According to the example, this further support module 8 ′ is identical to the support module 8 and is arranged on the side of the electric motor 1 opposite the support module 8 . This results in a further improvement in vibration damping and a further increase in the rigidity of the drive unit 2. In addition, unwanted distortion of the housing 3 can advantageously be avoided, since the pressing forces generated by the support modules 8 and 8' are directed in opposite directions, so that no bending force is exerted on the Housing 3 acts.

3 shows an example and schematically yet another possible embodiment of a drive unit according to the invention 2. The embodiment of 3 differs from those in 1 and 2 Forms of embodiment shown by way of example in that another support module 8" is provided. This further support module 8" is identical to the support modules 8, 8" and is arranged on the underside of the electric motor 1. This results in even further improved vibration damping and an even further increased rigidity of the drive unit 2.

4 shows an example and schematically yet another possible embodiment of a drive unit according to the invention 2. The perspective view of FIG 4 the support module 8''' can be seen, which rests exactly horizontally on the rear bearing plate of the electric motor 1

Reference List

1

electric motor

2

drive unit

3

Housing

4

carrying device

5

front bearing plate

6

front yoke

7

terminal box

8th

support module

8th'

support module

8th''

support module

8th'''

support module

Claims (13)

Drive unit (2) for a drive train test rig for testing electrical motor vehicle drive trains, comprising an electric motor (1) with a housing (3) and a carrying device (4) for carrying the electric motor (1), the housing (3) having a front end shield ( 5) of the electromor (1) comprises a mechanical front yoke (6) integrally connected and a mechanical rear yoke integral with a rear bearing plate of the electromor (1), the front yoke (5) and the rear yoke being located respectively above the electric motor ( 1) stretch in both lateral directions from the electric motor (1), the support device (4) carrying the electric motor (1) via the front yoke (6) and the rear yoke, so that below and to the side of the electromo tors (1) free spaces are formed, and wherein the drive unit (2) further comprises at least one support module (8, 8', 8'', 8'''), which additionally supports the housing (3) against the carrying device (4). characterized in that the at least one support module (8, 8', 8'', 8''') is designed as a vibration damper and that the at least one support module (8, 8', 8'', 8''') is screw-threaded , Can be clamped by means of a spring or by means of insertable wedges. Drive unit (2) after claim 1 , characterized in that the at least one support module (8, 8', 8'', 8''') can be screwed to the housing (3) and the carrying device (4) by means of threaded bores provided for this purpose. Drive unit (2) according to at least one of Claims 1 and 2 , characterized in that the at least one support module (8, 8', 8'', 8''') rests against the front or the rear bearing plate (5). Drive unit (2) according to at least one of Claims 1 until 3 , characterized in that the at least one support module (8, 8', 8'', 8''') rests against the housing (3) either exactly horizontally or exactly vertically. Drive unit (2) according to at least one of Claims 1 until 4 , characterized in that at least one support module (8, 8', 8'', 8''') rests against the front or the rear bearing plate (5). Drive unit (2) according to at least one of Claims 1 until 5 , characterized in that two support modules (8, 8', 8'', 8''') rest against the front and the rear bearing plate (5). Drive unit (2) according to at least one of Claims 1 until 6 , characterized in that three support modules (8, 8', 8'', 8''') rest against the front and the rear bearing plate (5). Drive unit (2) according to at least one of Claims 1 until 8th , characterized in that the drive unit (2) further comprises a terminal box (7), wherein the terminal box (7) rests flush on an upper side of the front yoke (6) and on an upper side of the rear yoke and wherein the terminal box (7) additional Has stiffening struts. Drive unit (2) according to at least one of Claims 1 until 8th , characterized in that the front yoke (6) and/or the rear yoke has fluid bearing cooling. Drive unit (2) according to at least one of Claims 1 until 9 , characterized in that the housing (3) has a radial diameter of less than 270 mm. Drive unit (2) according to at least one of Claims 1 until 10 , characterized in that the electric motor (1) is designed to achieve speeds of up to 25000 rpm. Drive unit (2) according to at least one of Claims 1 until 11 , characterized in that the supporting device (4) and/or the front yoke (6) and/or the rear yoke consists at least partially of a mineral concrete or a polymer concrete surrounding a metallic skeleton. Drivetrain test bench for testing electric motor vehicle drivetrains, comprising a drive unit (2) according to at least one of Claims 1 until 12 .

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