Apparatus and method for aligning a test specimen axis with respect to a test stand axis

Abstract

The present invention relates to an apparatus (2) for aligning the axis (9) of a test specimen (3) with the axis (6) of a test stand (1). The apparatus includes a first plate (11) for fixing to a mounting plate (7) of the test stand (1) and a second plate (12) for fixing the test specimen (3). The first plate (11) and the second plate (12) are positioned planarly relative to each other and fastened by a fastening device (18), which can assume at least two fastening states, specifically an aligned state and a fixed state. In the aligned state, the two plates (11, 12) can be displaced parallel to each other, and in the fixed state, the two plates (11, 12) are fixed relative to each other. An adjustment device (22) is also provided for displacing one of the two plates (11, 12) parallel to the other plate (11, 12) in the aligned state.

Description

[Technical Field]

[0001] The present invention relates to an apparatus and method for aligning the axis of a test specimen relative to the axis of a test stand. [Background technology]

[0002] With the increasing use of electric motors as a driving source for automobiles and other vehicles, it has become necessary to test and evaluate the driving behavior of electric motors on a test bench, just as is the case with internal combustion engines. To minimize interference, the motor axis of the electric motor (specimen) under test must be precisely aligned with the axis of the test bench. The motor axis is the geometric center axis or axis of rotation of the motor shaft. The test bench axis is therefore the geometric center axis or axis of rotation of the test bench shaft. The term "axis" should therefore be understood as a geometric element that defines the respective position and arrangement of the associated shafts.

[0003] For example, inaccurate alignment of the two axes due to parallel or angular offset of the specimen axis relative to the test stand axis can lead to vibrations in the subsequent test procedure, causing measurement errors and damage to the specimen or test stand.

[0004] Therefore, the electric motor to be tested must be installed on the test stand with extremely high precision, which requires repeated measurements and alignment corrections when installing the electric motor, requiring a great deal of effort.

[0005] During specimen assembly and alignment, the test bench is occupied and cannot be used for other testing operations. Summary of the Invention [Problem to be solved by the invention]

[0006] SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a method for easily and conveniently aligning the shaft of an electric motor serving as a test specimen with the shaft of a test stand. [Means for solving the problem]

[0007] The object according to the invention is achieved by an apparatus having the features of claim 1 and a method according to the independent claims. Furthermore, a test stand system is defined in which the apparatus can be advantageously used. Advantageous embodiments are defined in the dependent claims.

[0008] An apparatus for aligning the axis of a test specimen relative to the axis of a test stand is provided, the apparatus comprising a first plate configured to be fastened to a mounting plate of the test stand and a second plate configured to fasten the test specimen, the first plate and the second plate being arranged parallel to each other and fastened to each other by a fastening device, wherein the fastening device has at least two fastening states, i.e., an aligned state and a fastening state, in which the two plates can be displaced parallel to each other in the aligned state and the two plates can be fastened to each other in the fastening state, and an adjustment device is provided for displacing one of the two plates parallel to the other plate in the aligned state.

[0009] The device is therefore suitable for aligning the axis of the test specimen with the axis of the test stand. In particular, if the test specimen comprises an electric motor with a motor shaft and, on the test stand side, a dynamometer with a dynamometer shaft, this can correspond to the (geometric) axes of the respective shafts. The two axes, and therefore the shafts, need to be aligned as precisely as possible with respect to one another in order to minimize axial or parallel offsets on the one hand and angular offsets on the other hand.

[0010] This device does not constitute the test stand or the test specimen itself; rather, it serves as a kind of adapter, connecting the test specimen and the test stand in order to secure the test specimen to the test stand in a simple manner. In particular, this device allows the test specimen to be aligned before being attached to the test stand. As will be explained later, this makes it possible to first secure the test specimen to the device and then align the specimen relative to the device. The aligned specimen can then be secured to the test stand together with the device, without the need for further readjustment.

[0011] In particular, the test specimen can be secured to a second plate of the apparatus, which can then be aligned with the second plate relative to the first plate. The first plate, along with the second plate and the test specimen carried thereon, is then secured (mounted) to the test stand. Once aligned, the entire apparatus, with the already mounted and aligned test specimen, can be secured as a unit to the mounting plate of the test stand. Subsequent readjustment is no longer necessary, as the specimen is now optimally positioned with its axis aligned with the axis of the test stand.

[0012] The first and second plates are in flat contact with each other, i.e., across the entire contact plane, but the plates do not have to be perfectly flat. They may have different contours, particularly different depths.

[0013] The displacement of the two plates relative to one another by the adjusting device, especially the translational or rotational displacement required for alignment, is only possible when the fastening device is in alignment. Otherwise, the fastening device secures the two plates to one another and no relative displacement of the plates is possible.

[0014] The displacement of the two plates relative to each other occurs at the interface, i.e., the contact area where the two plates come into contact with each other. This displacement consists of both a linear or parallel displacement and a torsion, where the two plates rotate relative to each other within the plane of their surfaces.

[0015] The test specimen is first attached to the second plate. If the test specimen is an electric motor, the motor can be fastened to the second plate via its front flange, particularly by screw fastening. The second plate can then be connected to the first plate, and the two plates can be fastened to each other by a fastening device. Once the test specimen is mounted and aligned, the first plate can be fastened to the mounting plate of the test stand.

[0016] The fastening device can have at least one threaded connection acting between the first and second plates. The threaded connection is tightly fastened in the locked state and loosened in the aligned state to allow the two plates to move relative to each other. In other words, the threaded connection presses the plates tightly together in the locked state, preventing them from moving relative to each other, so the plates are always held flat and adjacent to each other. In the aligned state, the threaded connection is loosened enough to allow the two plates to move relative to each other. Of course, some friction must remain between the two plates to prevent them from moving apart. Accurate alignment requires that the plates always be in flat contact and have a certain amount of friction between them. Loosening or lifting the plates should be avoided, as this could cause the plates to tilt relative to each other, making their translation impossible.

[0017] The adjustment device can be configured to generate a force between the first plate and the second plate due to the relative displacement of the two plates. In particular, it can generate a force that extends parallel to the contact surface between the two plates. The adjustment device can be supported on one plate and exert a force on the other plate. This allows one plate to be displaced relative to the other plate. The displacement can consist, for example, of a parallel displacement and / or a rotation of the two plates relative to each other.

[0018] The adjusting device can have multiple screw devices, at least one of which has a screw mount fixed to one of the plates, and a screw bolt can be screwed into the screw mount. An end face of one of the screw bolts acts on one of the two plates to which the screw mount is not fixed, thereby applying a force to that plate. The screw bolt is screwed into the thread of the screw mount and can be rotated in this thread, in particular like a screw. Rotating the screw bolt causes axial movement.

[0019] When the screw bolt is in contact with the plate it acts on, a force is applied to the plate at the end face of the screw bolt, displacing the plate relative to the other plate.

[0020] The screw mounts and / or the screw bolts that can be screwed into the screw mounts can be positioned on the side of each plate, with the side perpendicular to the contact surface where the two plates rest flat against each other, so that the force exerted by the screw bolts acts transversely on the plates, i.e., parallel to the contact surface of the two plates.

[0021] The first and second plates each have a rectangular parallelepiped shape with two parallel plate faces and four side faces connecting the two plate faces. The adjustment device can have eight screw devices, two of which are respectively located at a distance from each other on the side faces of the plate. In each case, one of the plate faces is a contact surface for the respective contact surface of the opposite plate.

[0022] The shape of the plates need not be strictly cubic; for example, they can be approximate cubes with recesses or sawtooth. The important factor is that the plates have four sides that are perpendicular or parallel to each other, and that screw devices located there allow one plate to move relative to the other in a plane. Thus, using a coordinate system, the plates can be linearly displaced or rotated in the x and y directions, but not in the z direction (which means the two plates lift away from each other).

[0023] Typically, the test specimen may be an electric motor, which may have a flange or a front flange for fixing the electric motor to the second plate.

[0024] A support frame may be provided that is fixed to the second plate. The support frame may serve to stiffen the entire arrangement of the first and second plates. In particular, the support frame may serve to transport the apparatus with the test specimen attached thereto. Furthermore, the support frame may be configured to support the test specimen to avoid bending or lateral moments on the specimen housing or the specimen shaft.

[0025] To support the test specimen fixed to the second plate, support elements may be provided on the support frame, which may be formed, for example, by support bolts or support columns, and which support the test specimen, particularly on its underside, in order to hold and secure the test specimen securely on the support frame.

[0026] The device can be used particularly advantageously as an alignment device for aligning and fixing test specimens in test stand systems known per se.

[0027] The present invention provides a test stand system comprising an electric motor to be used as a test specimen, a test stand for testing the electric motor, a shaft of the test stand to which the shaft of the electric motor can be fixed in order to transmit the motion of the electric motor to the test stand, and a mounting plate provided on the test stand, the test stand system comprising a device of the aforementioned type as an alignment device for fixing and aligning the electric motor to the mounting plate.

[0028] Such test stands, which do not have the aforementioned (alignment) device, are known per se. As a rule, they have a drive or load device, such as a dynamometer, whose shaft corresponds to the test stand shaft. The test stand shaft is a component of the test stand and can be connected, for example, by a suitable coupling, to the shaft of the test specimen (here, the shaft of the electric motor). In this way, the movements of the test specimen and the load or drive device are precisely coordinated with each other. In particular, a dynamometer can be operated as a load device, thereby exerting a load torque on the electric motor. In this way, standard driving situations can be simulated with the electric motor.

[0029] Additionally or alternatively, the dynamometer can be operated as a drive device, with a drive torque acting on the electric motor, which is not driven in this case. In this way, a free-running mode can be realized. Of course, the electric motor of the test specimen can also be operated as a generator to investigate the braking load on the driving dynamometer. In this way, the braking behavior of the test specimen can be investigated in free-running mode.

[0030] In particular, the electric motor and dynamometer can be operated as motors or generators in different combinations (motor-motor, motor-generator, generator-motor, generator-generator), enabling so-called four-quadrant operation.

[0031] The test stand includes a mounting plate to which the electric motor can be coupled. Therefore, by using the alignment device described above, the electric motor can be optimally aligned before being attached to the mounting plate. Therefore, the electric motor is fixed to the mounting plate together with the alignment device, and no further adjustment or alignment is required.

[0032] The mounting plate may be plate-like, but may also be designed as a block or frame. It is expedient for the mounting plate to have a mounting surface on which an alignment device with an electric motor can be fixed.

[0033] In the alignment device, the first plate, the second plate, the electric motor fixed to the second plate, and the support frame may form a pre-assembled single unit and be fixed to the mounting plate as a single unit. Thus, as already described above, the electric motor can be first fixed to the second plate. Then, the relative position of the second plate to the first plate is adjusted, and the motor shaft, i.e., the axis of the electric motor, is accurately aligned to the desired position (parallel position, angular position) relative to the first plate to minimize the offset from the test stand later. The relative position of the two plates can be adjusted using a high-precision three-dimensional measuring device.

[0034] The first plate and the second plate with the electric motor attached are secured to the support frame to form a compact pre-assembled unit, which is then aligned, adjusted and secured to the mounting plate.

[0035] In particular, the first plate of the unit can be fixed to a mounting plate. For this purpose, a centering device can be provided for centering the first plate relative to the mounting plate. The centering device can, for example, have a centering pin so that the first plate can be accurately fixed to the mounting plate of the test stand.

[0036] The shaft of the electric motor is precisely aligned with the first plate in advance, so that the shaft of the electric motor is positioned accurately with respect to the shaft of the test stand with as little offset or error as possible.

[0037] A method for aligning the axis of the test specimen with the axis of the test stand is specified, the method comprising: providing a first plate and a second plate; placing a first plate and a second plate with their respective flat surfaces overlapping one another; securing the test specimen to a second plate; measuring the axis of the test specimen and comparing the position of the axis with a predetermined reference position (position, angle) relative to the first plate; aligning the axis of the test specimen with respect to the first plate by displacing a second plate supporting the test specimen relative to the first plate to minimize deviation of the axis position from a reference position; fastening the first plate and the second plate; securing the support frame to the second plate such that the first plate, the second plate, the test specimen, and the support frame form a single unit; and securing the unit to a mounting plate on a test stand.

[0038] These advantages and features of the invention are explained in more detail in the following text on the basis of examples using the attached figures. [Brief explanation of the drawings]

[0039] [Figure 1] 1 is a schematic side view of a test stand system showing a test stand shown schematically and an alignment device supporting a test specimen in cross section. [Figure 2] FIG. 2 is a perspective view of the alignment device and test piece of FIG. 1 as seen from above. [Figure 3]3 is a perspective view of the alignment device of FIG. 2 together with a test piece, seen from below. [Figure 4] 3 shows the alignment device of FIG. 2 without the test specimen. DETAILED DESCRIPTION OF THE INVENTION

[0040] 1 shows a side view of a schematic setup of a test stand system comprising a test stand 1 shown schematically and an alignment device 2 according to the invention to which an electric motor 3 serving as a test specimen is fixed. The alignment device 2 serves not only to align the electric motor 3 relative to the test stand 1 but also to pre-assemble and subsequently fix the electric motor 3 to the test stand 1.

[0041] Test stand 1 includes as load and driver a dynamometer 4, which is only symbolically depicted in Figure 1. Dynamometer 4 is, for example, an electric motor operable as a generator and motor, with the motor shaft forming test stand shaft 5. Dynamometer 4 and test stand shaft 5 are not drawn to scale in Figure 1 and are only for the purpose of illustrating the test stand system.

[0042] The position of the dynamometer 4 and the test stand shaft 5 also defines a test stand axis 6 which corresponds to the centre or axis of rotation of the test stand shaft 5 .

[0043] The elements of the test stand 1 also include a mounting plate 7 to which the electric motor 3 is fixed for the test procedure.

[0044] The electric motor 3 has a motor axis 8 which defines a geometric specimen axis 9 .

[0045] During the test procedure, the motor axis 8 of the test specimen (electric motor 3) is connected to the axis 5 of the test stand of the dynamometer 4, for example via a suitable coupling. During this process, it is particularly important that the axis 9 of the test specimen and the axis 6 of the test stand are precisely aligned with each other. Any offset, whether parallel or angular, will cause out-of-roundness during the test run and impair the measurement results. In the worst case, if the alignment error is too large, the specimen and / or the test stand may be damaged.

[0046] The alignment device 2 is provided to facilitate alignment and simplify the work process on the test bench.

[0047] The alignment device 2 comprises a support frame 10 , a first plate 11 and a second plate 12 .

[0048] The alignment device 2 is shown in different views in Figures 2 and 3 together with the electric motor 3. In Figure 4 the alignment device 2 is depicted without the electric motor 3. Figures 1 to 4 each show the same alignment device 2 and the following description refers to all figures.

[0049] The support frame 10 is designed as a stable angular body, and is composed of a bottom plate 13, support walls 14 that are vertical when installed on the test stand 1, and reinforcing ribs 15. Each element of the support frame 10 may be formed, for example, as a welded structure or may be machined from solid material. In particular, the underside of the bottom plate 13 must be machined with high precision, since the support frame 10 slides on a corresponding holder on the test stand 1, for example, on a support base provided on the test stand 1. Spring elements 16 are provided to accurately guide the support frame and can be inserted into corresponding groove recesses (not shown) provided on the support base of the test stand 1.

[0050] The second plate 12 is fixed to an end face of the support frame 10, in particular to an end face of the support wall 14, for example by a screw connection. The first plate 11 is arranged planarly on the second plate 12. The first plate 11 and the second plate 12 are connected to each other by screws forming a fastening device, which can be screwed firmly together.

[0051] The electric motor 3 is fixed to the second plate 12, for example, via a front flange present on the end face of the housing of the electric motor 3. Furthermore, in particular the rear part of the electric motor 3, remote from the second plate 12, is supported on the bottom plate 13 by a support element 17. This ensures that the electric motor 3 is securely fixed to the support frame 10 and the second plate 12 during operation of the test stand, where vibrations and force loads can occur at high speeds.

[0052] The support frame 10, the first plate 11 and the second plate 12, together with the electric motor 3 fixed thereto, form a compact single unit.

[0053] To align the test specimen axis 9 of the electric motor 3, the second plate 12 can be displaced in a plane relative to the first plate 11. To do this, the fastening device 18 must first be loosened. To do this, the screws connecting the first plate 11 and the second plate 12 must be loosened, but the screws can only be loosened enough to allow the first plate 11 and the second plate 12 to move relative to each other at their contact surfaces. During this process, the first plate 11 and the second plate 12 must not move apart. What is important is that they can be displaced relative to each other.

[0054] On the end faces of the first plate 11 and the second plate 12, each screw device 19 is provided with a screw mount 20 and a screw bolt 21 that can be screwed into the inside thereof, which together form part of an adjustment device 22.

[0055] A total of eight such screw devices 19 are arranged on the outer periphery of the first plate 11 and the second plate 12, two on each side, and these together form an adjustment device 22.

[0056] In this case, the screw mounts 20 are fixed to the first plate 11 and can support the screw bolts 21. By rotating the screw bolts 21, a force can be applied to the side surface of the corresponding second plate 12 via the end face of the screw bolt 21. In other words, in response to the rotation of the screw bolts 21, the second plate 12 is displaced relative to the first plate 11 with high precision. In response to this, the electric motor 3 fixed to the second plate 12 is also displaced.

[0057] During this displacement, the position of the motor shaft 8, and therefore the position of the test specimen shaft 9, relative to the reference position of the first plate 11 can be measured multiple times using high-precision measuring equipment. Once the test specimen shaft 9 is in a precise relative position to the first plate 11 and no deviation from the reference position (angle) defined by the first plate 11 is detected, the fastening device 18 can be closed by tightening the connecting screw between the first plate 11 and the second plate 12, and relative displacement between the first plate 11 and the second plate 12 is no longer possible.

[0058] In this case, the first plate 11, the second plate 12, together with the support frame 10 and the electric motor 3, form a compact and stable single unit, and the axis 9 of the test specimen is accurately positioned at a predetermined position (reference position). When this compact unit is then fixed to the mounting plate 7 of the test stand 1 via the first plate 11, the axis 9 of the test specimen and the axis 6 of the test stand are accurately aligned with each other. In this way, parallel offset and angular offset can be substantially eliminated.

[0059] Pre-assembly and alignment of the electric motor may, for example, consist of the following steps: In a pre-assembly workshop (not shown), the second plate 12 is placed horizontally on top of the first plate 11 . The test specimen (electric motor 3) is placed on the second plate 12. In this case, the motor shaft 8 projects vertically downward. A highly accurate three-dimensional measuring device is used to measure the position (condition, direction) of the motor shaft 8 and, in turn, the axis 9 of the test stand. By horizontally or parallelly displacing the second plate 12 on the first plate 11, the motor shaft 8 and thus the axis 9 of the test specimen are aligned. Fastening devices 18 are used to secure the first plate 11 to the second plate 12 . The entire apparatus (including the support frame 10 fixed to the second plate 12) is rotated 90°. The spring elements 16 present on the support frame 10 are placed on the corresponding support bases of the test stand 1, and the support frame 10 is slid over the support bases, guiding the spring elements 16 into the corresponding grooves of the support bases. The support frame 10 is moved together with the first plate 11 and the second plate 12 until the first plate 11 contacts the mounting plate 7 of the test stand 1. Afterwards, the first plate 11 and the second plate 12 are connected to the mounting plate by means of screw connections.

[0060] In order to position the first plate 11 correctly on the mounting plate 7, suitable centering elements must be provided, for example at least two centering bolts.

[0061] In the example shown, centering is achieved by a ring centering with a cylindrical shoulder 23 on the first plate 11. A corresponding hollow cylindrical recess (not shown) is provided in the mounting plate 7 corresponding to the shoulder 23.

Claims

1. A device (2) for aligning an axis (9) of a test specimen (3) with an axis (6) of a test stand (1), comprising: a first plate (11) configured to be fixed to the mounting plate (7) of the test stand (1); a second plate (12) configured to fix the test piece (3); The first plate (11) and the second plate (12) are arranged flat in contact with each other and fastened together by a fastening device (18); the fastening device (18) has at least two fastening states, namely an aligned state and a locked state, in which the two plates (11, 12) are displaceable parallel to each other in the aligned state and in which the two plates (11, 12) are locked to each other in the locked state; The device comprises an adjustment device (22) for displacing one of the two plates (11, 12) parallel to the other plate (11, 12) in the aligned state.

2. the fastening device (18) comprises at least one threaded connection acting between the first plate (11) and the second plate (12); 2. The device according to claim 1, wherein the screw connection is tightly fastened in the fixed state and loosened in the aligned state so that the two plates (11, 12) are displaceable relative to each other.

3. 10. The device according to claim 1, wherein the adjusting device (22) is configured to generate a force between the first plate (11) and the second plate (12) due to a relative displacement of the two plates (11, 12).

4. The adjustment device (22) has a plurality of screw devices (19), At least one of the screw devices (19) comprises a screw mount (20) fixed to one of the two plates (11, 12); A threaded bolt (21) is screwed into the inside of the screw mount (20), 10. The device according to claim 9, wherein one end face of the screw bolt (21) acts on the plate (11, 12) of the two plates (11, 12) to which the screw mount (20) is not fixed, thereby allowing a force to be applied to that plate (11, 12).

5. the screw mounts (20) and / or the screw bolts (21) that can be screwed into the inside of the screw mounts (20) are arranged on the sides of the respective plates (11, 12); 10. A device according to any one of the preceding claims, wherein the side surfaces are perpendicular to the contact surface where the two plates (11, 12) meet flatly.

6. the geometric shape of the first plate (11) and the second plate (12) each corresponds to a rectangular parallelepiped plate having two parallel plate faces and four side faces connecting the two plate faces; 10. The device according to claim 1, wherein the adjusting device (22) comprises eight of the screw devices (19), two of which are arranged on each side of the plate at a distance from each other.

7. 10. An apparatus according to any one of the preceding claims, wherein the test piece is an electric motor (3).

8. 10. An apparatus according to any one of the preceding claims, comprising a support frame (10) fixed to said second plate (12).

9. 10. An apparatus according to any one of the preceding claims, wherein the support frame (10) is provided with support elements (17) for supporting the test specimen (3) fixed to the second plate (12).

10. 1. A test stand system comprising: an electric motor (3) serving as the test piece; a test stand (1) for testing the electric motor (3); a test stand shaft (5) for fixing the shaft (8) of the electric motor (3) and transmitting the movement of the electric motor (3) to the test stand (1); a mounting plate (7) provided on the test stand (1); and a device (2) according to any one of the preceding claims as an alignment device for fixing and aligning the electric motor (3) with the mounting plate (7).

11. 11. The test stand system of claim 10, wherein the first plate (11), the second plate (12), the electric motor (3) fixed to the second plate (12), and the support frame (10) constitute a pre-assembled unit that can be fixed as a single unit to the mounting plate (7).

12. 12. A test stand system according to claim 10 or 11, wherein the first plate (11) of the unit is fixable to the mounting plate (7).

13. 13. A test stand system according to any one of claims 10 to 12, comprising a centering device (23) for centering the first plate (11) relative to the mounting plate (7).

14. A method for aligning an axis (9) of a test specimen (3) with an axis (6) of a test stand (1), comprising the steps of: providing a first plate (11) and a second plate (12); placing the first plate (11) and the second plate (12) with their respective flat surfaces overlapping each other; Fixing the test specimen (3) to the second plate (12); measuring the axis (9) of the test piece (3) and comparing the position of the axis (9) with a predetermined reference position relative to the first plate (11); aligning the axis (9) of the test specimen (3) with respect to the first plate (11) by displacing the second plate (12) supporting the test specimen (3) relative to the first plate (11) to minimize deviation of the position of the axis (9) from the reference position; fixing the first plate (11) and the second plate (12); fixing the support frame (10) to the second plate (12) so that the first plate (11), the second plate (12), the test specimen (3) and the support frame (10) form a single unit; and fixing said unit to a mounting plate (7) of said test stand (1).

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