POWERTRAIN TEST BENCH WITH ADJUSTABLE TEST SPECIMEN SUPPORT

Description

[0001] The invention relates to a powertrain test bench according to the preamble of claim 1.

[0002] Transmission test benches or powertrain test benches for testing motor vehicle transmissions or entire motor vehicle powertrains are well known in the art. Such test benches are typically used to detect malfunctions in powertrains at an early stage through a series of stress tests. Furthermore, such test benches are also used in the development and continuous improvement of motor vehicle powertrains, and in particular motor vehicle transmissions. Typically, these test benches are designed for testing combustion-engine motor vehicle powertrains.

[0003] Test benches suitable for testing combustion-engine vehicle powertrains are typically not suitable for testing electric powertrains, as electric powertrains operate at significantly higher speeds of more than 10,000 rpm. Therefore, drivetrain test benches for electric vehicle drives have special requirements regarding rigidity and vibration damping. In addition, electric powertrains must be aligned very precisely due to the high speeds in the test bench.

[0004] In this context, DE 10 2016 224 142 A1 describes a modular powertrain test bench for electric vehicle drives that is particularly rigid and vibration-damping. At the same time, it allows precise alignment of the transmission to a drive unit of the test bench.

[0005] EP 3 081 915 A1 discloses a bearing testing machine comprising a testing machine shaft to which a bearing, which is a test piece, is attached. The testing machine shaft is a rotary shaft extending horizontally in the Y-axis direction. Furthermore, the bearing testing machine comprises a rotary drive unit configured to rotate the testing machine shaft, a test piece holding unit configured to elastically hold the test piece, and a plurality of axis drive units configured to move the testing machine shaft vertically in the Z-axis direction and horizontally in the X- and Y-axis directions, wherein the X-axis direction is orthogonal to the Y-axis direction. The shaft is also tiltable about the Z-axis and the X-axis.

[0006] DE 10 2018 127 572 A1 discloses a pivoting frame for a test bench for a drive train, comprising a support frame, a motor mount movable relative to the support frame, to which a drive motor can be mounted, and a front lifting device and a rear lifting device, relative to a main direction. The motor mount is supported by the front lifting device and the rear lifting device when moved relative to the support frame, wherein the motor mount can be pivoted relative to the support frame by the lifting devices about a front pivot axis and a rear pivot axis.

[0007] However, the known test benches for electric vehicle powertrains have the disadvantage that they have to be precisely adjusted for the respective powertrains to be tested, which is very time-consuming.

[0008] It is an object of the present invention to propose an improved powertrain test bench.

[0009] This object is achieved according to the invention by the powertrain test bench according to claim 1. Advantageous embodiments emerge from the subclaims.

[0010] The invention relates to a drive train test bench for testing an electric vehicle drive, comprising a drive module and an adjustable test specimen holder for a drive train test bench, wherein the test specimen holder and the drive module are connected to one another via a common base, wherein the drive module encloses an electric motor, wherein the test specimen holder has a first surface and a second surface parallel to the first surface, wherein the test specimen holder can be arranged on a base via the first surface, wherein a test specimen can be arranged on the second surface and wherein the test specimen holder is designed such that the second surface is adjustable relative to the first surface along a longitudinal axis, a height axis and a transverse axis.The test specimen holder is further designed such that the second surface can be tilted relative to the first surface at least about the height axis and the transverse axis, wherein the drive module comprises a flange, wherein the electric motor can drive the test specimen via the flange and the axes of the test specimen and the electric drive to be coupled can be aligned without offset.

[0011] A test specimen holder is therefore provided which is suitable as part of a powertrain test bench for holding a test specimen. The test specimen is preferably a vehicle transmission, in particular a vehicle transmission for an electrically powered vehicle. Such a vehicle transmission for an electrically powered vehicle differs from a vehicle transmission for combustion engine-powered vehicles primarily in that it is designed for significantly higher input speeds of over 10,000 rpm. In addition, a vehicle transmission for an electrically powered vehicle generally has comparatively fewer shiftable gears. However, the test specimen can also be not only the vehicle transmission but, for example, the vehicle transmission with connected output shafts and transfer cases right down to the individual wheel drive shafts.It is also conceivable and preferred for the test object to be exclusively an electric drive motor for an electrically powered vehicle. In this case, the electric drive motor can in particular be subjected to a so-called "back-to-back" test, i.e., a load test in which the electric drive motor for the electrically powered vehicle is directly coupled to a drive of the powertrain test bench. The drive of the powertrain test bench is also an electric motor. Because a coupling is used as the coupling element between the test object and the drive of the powertrain test bench, it is necessary to align the test object as precisely as possible to the drive. A coupling is advantageous for transmitting high speeds, as is common for electric powertrains, but requires offset-free alignment of the axles to be coupled.To ensure this alignment as precisely as possible, the invention provides not only adjustability of the second surface along the longitudinal axis, the vertical axis, and the transverse axis relative to the first surface, but also tiltability of the second surface about the vertical axis and the transverse axis relative to the first surface. This ensures a largely optimal alignment of the test specimen in a reliable and simple manner. In particular, the occurrence of undesirable vibrations due to insufficient alignment can be avoided.

[0012] The first surface and the second surface of the test specimen holder are preferably made of metal and are essentially flat. They can have slots or openings or large-area recesses. The first surface forms an underside of the test specimen holder, on which the test specimen holder can be placed. Slots or openings in the first surface are advantageously provided to enable attachment to a base for the test specimen holder. A comparatively large-area recess is also preferred, for example to reduce weight. The second surface forms an upper side of the test specimen holder, on which the test specimen can be arranged. Advantageously, a plurality of holders, in particular four holders, for clamping the test specimen can be arranged by means of the slots or openings in the second surface. The first and the second surface are preferably rectangular.

[0013] The longitudinal axis, the height axis and the transverse axis are three mutually orthogonal axes, where the longitudinal axis defines a direction along the long side edge of the first surface, the transverse axis defines a direction along the short side edge of the first surface and the height axis is perpendicular to the first surface.

[0014] According to a preferred embodiment of the invention, the second surface is adjustable relative to the first surface along the height axis by means of at least two displaceable wedges. The at least two wedges are preferably of identical design. They have a triangular cross-section and have two long side edges and one short side edge. This initially results in the advantage that the first surface and the second surface are connected to one another via the at least two wedges, with the first surface resting against one long side edge of the wedges and the second surface resting against the other long side edge of the wedges. Such comparatively large contact surfaces result in a vibration-damping and rigid connection between the first surface and the second surface.

[0015] Each wedge is preferably displaceable along the first surface or the second surface via a spindle thread, in particular displaceable along an incline of the first surface or the second surface, so that, depending on the position of the wedges, a displacement of the first surface along the height axis relative to the second surface results. By displacing the wedges, a comparatively fine adjustment of the height of the second surface relative to the first surface is thus made possible in a very simple manner. In particular, it is not necessary, as is often customary in the prior art, to set the desired height of the second surface relative to the first surface by means of shims.

[0016] According to a further preferred embodiment of the invention, the at least two wedges are arranged on a first intermediate plate, wherein the first intermediate plate in particular has a bevel on its upper side, which corresponds opposite to a bevel of the wedges such that an underside of the first intermediate plate and a respective long side edge of the at least two wedges are parallel to one another. By using the first intermediate plate, the advantage is that adjustment options or tilting options of the second surface relative to the first surface along other axes are not impaired.

[0017] According to a further preferred embodiment of the invention, it is provided that the at least two displaceable wedges are arranged in a displacement-proof manner on the first surface or on the second surface and are displaceable on the respective other surface on a slope provided for this purpose, such that displacement of the at least two wedges simultaneously leads to an adjustment of the first surface along the vertical axis and along the transverse axis or the longitudinal axis. By the at least two wedges being arranged in a displacement-proof manner either on the first surface or on the second surface, the first or the second surface moves accordingly together with the at least two wedges. As a result, displacement of the at least two wedges along the slope not only causes displacement along the vertical axis, but also along the transverse axis or the longitudinal axis.

[0018] According to a further particularly preferred embodiment of the invention, it is provided that the at least two wedges each have, on their side edge facing the second surface, a curvature extending over the side edge. The curvature can, for example, be designed as a circular arc in cross-section and extend over the entire length or a partial length of the side edge of the respective wedge. This results in the advantage that the second surface is not connected to each of the at least two wedges via two adjacent surfaces, but rather that there is only one contact line at which the second surface rests on each of the at least two wedges. It is also conceivable for the curvature to extend with interruptions over the side edge of the respective wedge facing the second surface; in particular, the curvatures can even be spherical segments.Thus, for example, when one or more wedges are moved, slight tilting of the wedges can be compensated with regard to the alignment of the second surface on the corresponding wedge.

[0019] According to another particularly preferred embodiment of the invention, a position of the at least two wedges can be detected by means of at least one depth caliper. Thus, the position of the at least two wedges can be easily detected. Since the displacement of the second surface relative to the first surface along the height axis is determined by the position of the wedges, the height of the second surface above the first surface can also be easily determined.

[0020] Preferably, a separate depth caliper is provided for each wedge.

[0021] According to a further preferred embodiment of the invention, the second surface is adjustable relative to the first surface along the longitudinal axis by means of a longitudinal spindle drive and along the transverse axis by means of a transverse spindle drive. Spindle drives allow precise and reliable displacement of the second surface relative to the first surface. The longitudinal spindle drive can be arranged, for example, between the first surface and the second surface along the longitudinal axis, and the transverse spindle drive can be arranged, for example, between the first surface and the second surface along the transverse axis.

[0022] According to a further preferred embodiment of the invention, the second surface is tiltable relative to the first surface about the transverse axis by means of at least one of the at least two wedges. For this purpose, only one of the at least two wedges is displaced, or the at least two wedges are displaced by different distances, so that the wedges create a different spacing between the first surface and the second surface and the second surface is correspondingly inclined relative to the first surface. If the at least two wedges are arranged and displaceable at a distance from one another along the transverse axis, tilting of the second surface along the transverse axis can thus be enabled.

[0023] According to a further preferred embodiment of the invention, the second surface can be tilted relative to the first surface about the vertical axis by means of a tilting spindle drive about a bearing point. The tilting spindle drive can be arranged, for example, at a longitudinal end of the test specimen holder. By adjusting the tilting spindle drive, the first surface can then be tilted about the vertical axis, with the bearing point being the pivot point.

[0024] According to a particularly preferred embodiment of the invention, the bearing point is provided as a pivot bearing between the first surface and a second intermediate plate or between the second surface and the second intermediate plate. By using the second intermediate plate, the adjustment or tilting options of the second surface relative to the first surface along other axes are not impaired.

[0025] According to a particularly preferred embodiment of the invention, the bearing point is arranged in an outer quarter of the length of the test specimen holder. Since the bearing point represents the pivot point around which the first surface is rotated, the pivot point is also located in an outer quarter of the length of the test specimen holder.

[0026] Preferably, the bearing point is arranged in an outer quarter of the length of the test specimen holder, facing away from the tilting spindle drive. This means that the test specimen holder is divided longitudinally or transversely into four imaginary quarters, with the bearing point arranged in one outer quarter. This quarter is facing away from the other outer quarter, on which the tilting spindle drive is arranged. This results in the advantage that the different length ratios of the test specimen holder around the bearing point, i.e., by reducing the rotation arm, enable particularly sensitive rotation of the side of the second surface facing away from the tilting spindle drive.

[0027] According to a further preferred embodiment of the invention, a set orientation of the second surface relative to the first surface can be fixed by means of clamping screws. This ensures, particularly during operation of the powertrain test bench, that the orientation of the test specimen holder does not change unintentionally due to vibrations or acting forces.

[0028] According to a further preferred embodiment of the invention, the test specimen holder further comprises a base on which the first surface is arranged in a displacement- and tilt-resistant manner. The base allows the test specimen holder to be arranged at a height essentially suitable for the powertrain test bench. Advantageously, the base is made of a comparatively stiff, heavy, and vibration-damping material, in particular a mineral cast, which is very well suited for vibration damping.

[0029] The invention is explained below by way of example with reference to embodiments shown in the figures.

[0030] They show: Fig. 1 shows, by way of example and schematically, a possible embodiment of a drive train test bench according to the invention, Fig. 2 shows, by way of example and schematically, a possible embodiment of a test specimen holder according to the invention, Fig. 3 shows, by way of example, another possible embodiment of a test specimen holder according to the invention, and Fig. 4 shows, by way of example and schematically, as a cross-section, a possible embodiment of a curvature which is arranged on a side edge of a wedge facing the second surface 3.

[0031] Identical objects, functional units, and comparable components are designated by the same reference symbols throughout the figures. These objects, functional units, and comparable components are identical in terms of their technical features, unless explicitly or implicitly stated otherwise in the description.

[0032] Fig. 1shows an example and schematically a possible embodiment of a drive train test bench 100 according to the invention. The drive train test bench 100 comprises a drive module 50 and a test specimen holder 1 according to the invention. The drive module 50 houses a Fig. 1 not shown electric motor, which has a flange 51 which also has a Fig. 1 The test specimen holder 1 and the drive unit 50 are connected to each other via a common base 10, resulting in a particularly rigid and vibration-damping connection. For example, the base 10 is made of a mineral casting. The test specimen holder 1 further comprises a first surface 5 and a second surface 3, each of which is made of steel and Fig. 1are arranged parallel and one above the other. The first surface 5 represents a bottom side of the test specimen holder 1 and is arranged on the base 10 in a displacement- and tilt-proof manner. By means of a plurality of slots and openings in the second surface 3, a plurality of Fig. 1 not shown holders for clamping the test piece on the second surface 3. The test piece holder 1 is designed such that the second surface 3 is adjustable relative to the first surface 5 not only along a longitudinal axis X, a height axis Z and a transverse axis Y, but is also tiltable relative to the first surface 5 about the height axis and the transverse axis. The different axes and directions of rotation are shown in Fig. 1 illustrated by the arrows X, Y, Z, B and C, where B indicates a rotation around the transverse axis Y and C indicates a rotation around the vertical axis Z.

[0033] Fig. 2shows an example and schematically a possible embodiment of a test specimen holder 1 according to the invention. In Fig. 2a a fully assembled test specimen holder can be seen, comprising the first surface 5, a second surface 3, a first intermediate plate 4, a second intermediate plate 2 and two wedges 6, 6', wherein the wedges 6, 6' are in Fig. 2a are obscured by the second surface 3. Fig. 2b shows only the first surface 2 and the two wedges 6, 6', which are held on the first surface 2 by screws. Since the screws are guided through longitudinal slots of the wedges 6, 6', the wedges 6, 6' are each movable along the transverse axis Y. In Fig. 2cThe first surface 5 and the first intermediate plate 4 are also shown. As can be seen, the second intermediate plate 2 is arranged on the first surface 5. The first intermediate plate 4 spaces the wedges 6, 6' from the second intermediate plate 2 without impairing the displaceability of the wedges 6, 6'. The wedges 6, 6' can be displaced over the surface of the first intermediate plate 4 according to the longitudinal slots in the wedges 6, 6'. The second surface 3 is then arranged on the wedges 6, 6', also without restricting the displaceability of the wedges 6, 6'. Depending on how far the wedges 6, 6' are displaced, the spacing between the second intermediate plate 2 and the second surface 3 increases due to the wedge shape of the wedges 6, 6'. The second surface 3 is therefore adjusted along the height axis Z relative to the first surface 5. Fig. 2dFinally, a view of the test specimen holder 1 from below is shown. Due to the selected view, only the first surface 5 and the second intermediate plate 2 are visible.

[0034] Fig. 3 shows an example of another possible embodiment of a test specimen holder 1 according to the invention. The test specimen holder 1 also consists in this case of the first surface 5, the second surface 3, the first intermediate plate 4, the second intermediate plate 2 and two wedges 6, 6', wherein the wedges 6, 6' are again covered by the second surface 3. In enlarged individual views, Fig. 3shown: A tilting spindle drive 7 for tilting the second surface 3 via the second intermediate plate 2 relative to the first surface 5 about a bearing point 8 about the height axis Z, wherein the bearing point 8 is arranged in an outer quarter in the longitudinal direction of the test specimen holder 1, facing away from the tilting spindle drive 7. Also visible is a longitudinal spindle drive 9 for adjusting the second surface 3 via the second intermediate plate 2 relative to the first surface 5 along the longitudinal axis X. A transverse spindle drive 10 enables the second surface 3 to be adjusted via the first intermediate plate 4 relative to the first surface 5 along the transverse axis Y. By means of two wedge spindle drives 11, two wedges 6, 6' can be moved along the transverse axis Y, so that the second surface 3 moves along the height axis Z relative to the first surface 5.By moving only one wedge 6 or 6' along the transverse axis Y, the second surface 3 can be tilted about the transverse axis Y relative to the first surface 5. By means of a position indicator 12, a tilt orientation about the height axis Z of the second surface 3 relative to the first surface 5 can be determined. Finally, a coordinate display 13 supports an operator of the test specimen holder 1 in adjusting the test specimen holder 1 by the coordinate display illustrating the individual coordinate axes and thus simplifying the assignment of the spindle drives 7, 9, 10, 11 to an adjustment along a specific axis or around a specific axis.

[0035] Fig. 4shows, by way of example and schematically in cross-section, a possible embodiment of a curvature 14, which is arranged on a side edge of a wedge 6 facing the second surface 3 and extends at least partially over the length of the side edge. The curvature 14 results in only a narrow contact line between the wedge 6 and the second surface 3, which, moreover, does not lead to a change in the orientation of the second surface even in the event of an unintentional and only slight lateral twisting or tilting of the wedge 6. Reference symbol

[0036] 1Test specimen holder 2Second intermediate plate 3Second surface 4First intermediate plate 5First surface 6, 6'Wedge 7Tilt spindle drive 8Bearing point 9Longitudinal spindle drive 10Transverse spindle drive 11Wedge spindle drive 12Position indicator 13Coordinate indicator 14Curvature 50Drive module 51Flange 100Powertrain test bench XLongitudinal axis YTransverse axis ZHelevation axis BRotation around the transverse axis CRotation around the vertical axis Reference symbol

[0037] 1Test specimen holder 2Second intermediate plate 3Second surface 4 6,First intermediate plate 5First surface 6'Wedge 7Tilt spindle drive 8Bearing point 9Longitudinal spindle drive 10Transverse spindle drive 11Wedge spindle drive 12Position indicator 13Coordinate indicator 14Curvature 50Drive module 51Flange 100Powertrain test bench XLongitudinal axis YTransverse axis ZHelevation axis BRotation about the transverse axis CRotation about the vertical axis

Claims

1. Drivetrain test bench (100) for testing an electric vehicle drive, comprising a drive module (50) and an adjustable test object holder (1) for a drivetrain test bench (100), wherein the test object holder (1) and the drive module (50) are connected to one another via a joint base (10), wherein the drive module (50) encloses an electric motor, wherein the test object holder (1) has a first surface (5) and a second surface (3) parallel to the first surface (5), wherein the test object holder (1) can be arranged on a base via the first surface (5), wherein a test object can be arranged on the second surface (3), and wherein the test object holder (1) is formed such that the second surface (3) is adjustable relative to the first surface (2) along a longitudinal axis (X), a vertical axis (Z), and a transverse axis (Y), and wherein the test object holder (1) is further formed such that the second surface (3) is tiltable relative to the first surface (2) at least about the vertical axis (Z) and the transverse axis (Y), wherein the drive module (50) comprises a flange (51), wherein the electric motor can drive the test object via the flange (51) and the axes to be coupled of the test object and of the electric drive can be aligned in an offset-free manner.

2. Drivetrain test bench (100) according to Claim 1, characterized in that the second surface (3) is adjustable relative to the first surface (5) along the vertical axis (Z) by means of at least two displaceable wedges (6, 6').

3. Drivetrain test bench (100) according to at least one of Claims 1 and 2, characterized in that the at least two displaceable wedges (6, 6') are arranged on the first surface (5) or on the second surface (3) in a displaceably fixed manner and are displaceable on the respective other surface (5, 3) on a slope provided for this purpose, so that a displacement of the at least two wedges (6, 6') simultaneously leads to an adjustment of the first surface (5) along the vertical axis (Z) and along the transverse axis (Y) or the longitudinal axis (X).

4. Drivetrain test bench (100) according to at least one of Claims 1 and 2, characterized in that the at least two wedges (6, 6') are arranged on a first intermediate plate (4), wherein the first intermediate plate (4) has in particular a bevel on its upper side, which corresponds oppositely to a bevel of the wedges (6, 6') such that a lower side of the first intermediate plate (4) and a respective long side edge of the at least two wedges (6, 6') are parallel to one another.

5. Drivetrain test bench (100) according to at least one of Claims 2 to 4, characterized in that the at least two wedges (6, 6') each have, on their side edge facing the second surface (3), a curvature (14) extending over the side edge.

6. Drivetrain test bench (100) according to at least one of Claims 2 to 5, characterized in that a position of the at least two wedges (6, 6') can be detected by means of at least one depth gauge.

7. Drivetrain test bench (100) according to at least one of Claims 1 to 6, characterized in that the second surface (3) is adjustable relative to the first surface (5) along the longitudinal axis (X) by means of a longitudinal spindle drive (9) and along the transverse axis (Y) by means of a transverse spindle drive (10).

8. Drivetrain test bench (100) according to at least one of Claims 1 to 7, characterized in that the second surface (3) can be tilted relative to the first surface (5) by means of at least one wedge (6, 6') of the at least two wedges (6, 6') about the transverse axis (Y).

9. Drivetrain test bench (100) according to at least one of Claims 1 to 8, characterized in that the second surface (3) can be tilted relative to the first surface (1) by means of a tilting spindle drive (7) about a bearing point (8) about the vertical axis (Z).

10. Drivetrain test bench (100) according to Claim 9, characterized in that the bearing point is provided as a pivot bearing between the first surface (5) and a second intermediate plate (2) or between the second surface (3) and the second intermediate plate (2).

11. Drivetrain test bench (100) according to at least one of Claims 9 and 10, characterized in that the bearing point (8) is arranged in an outer quarter of the length of the test object holder (1).

12. Drivetrain test bench (100) according to at least one of Claims 1 to 11, characterized in that a set alignment of the second surface (3) relative to the first surface (5) can be fixed by means of clamping screws.

13. Drivetrain test bench (100) according to at least one of Claims 1 to 12, characterized in that the test object holder (1) further comprises a base (12) on which the first surface (5) is arranged in a fixed manner in terms of displacement and tilting.