Configuration for a rotating test bench

Abstract

In a configuration for a rotary test bench (1) having a shaft (4) which can be coupled in a rotationally fixed manner to a drive (3) via bearing elements (5) and a clamping holder (6) which is intended to receive a rotor (2) to be tested and which can be coupled in a rotationally fixed manner to the shaft (4), the invention proposes providing flexible spring elements (8) between the drive (3) and the shaft (4) and between the shaft (4) and the rotor (2). This design compensates for bending forces which are caused by vibrations of the rotor (2) and which act on the shaft (4) and / or the clamping holder (6).

Description

[Technical Field]

[0001] The present invention relates to an arrangement for a rotary test bench in which a rotor to be tested is driven in rotation on a flexible shaft. [Background technology]

[0002] To test the durability of rotors, rotationally symmetric structural components are typically subjected to a test procedure carried out on a rotating test bench in which a test sample is rotated up to a burst speed or another predetermined speed. In addition, the rotor may be subjected to, for example, cyclic speed changes or temperature fluctuations. Such a test bench is known from German Patent Publication No. 1 125 206 A.

[0003] The rotor can be suspended from a thin elastic shaft, for example by a shaft journal, and accelerated. The rotor then rotates about its inertial axis rather than its geometric axis, and therefore moves with virtually no unbalanced forces. Since the elastic natural frequency of the shaft is usually exceeded and large deflections can occur, dampers are often used to limit the shaft deflection and can limit the amplitude of the centrifugal shaft.

[0004] Damping systems are known from DE 102 06 950 A1, which for example discloses a vertically configured rotary test device in which a shaft is mounted on both the drive side and the component side and is coupled to a damping system on the component side.

[0005] German Patent No. 10 2011 087 909 B3 discloses an arrangement for a component test bench, which comprises a shaft for transmitting torque from a rotary drive to the component to be tested, the shaft being rotatably mounted in bearings on the component side and the drive side, the bearing on the component side being connected in a hexapod arrangement to a damping system so that vibrations caused by imbalance are damped.

[0006] Furthermore, German Publication No. 28 35 962 A discloses a separator with a vertically extending rotating shaft for the centrifuge basket. The rotating shaft is rotatably supported in fixed bearings on both sides and is further supported under tension by a ring rubber spring on the centrifuge basket side. In this way, the resonance position of the centrifuge basket is shifted to a harmless range during operation due to residual imbalance.

[0007] German Publication No. 693 08 430 T2 discloses a centrifuge having a rotor drive shaft formed by a flexible shaft surrounded by a sleeve, the shaft and the sleeve being non-rotatably connected to one another at one end, while the other end of the flexible shaft protrudes beyond the other end of the sleeve and holds a head that serves to hold the rotor of the centrifuge. Means are provided for internal damping to compensate for any axial misalignment caused by assembly errors. This damps radial movement of the shaft relative to the rotating sleeve. However, this does not cause any external damping relative to the stationary housing. Furthermore, the centrifuge is equipped with a flexible coupling including a tubular element made of silicone, into which a pin projects for non-rotatably coupling the motor shaft of the drive unit to the shaft.

[0008] A device for damping rotor vibrations is known from DE 694 04 161 T2.

[0009] In some cases, the structural component being tested, e.g., the rotor, must be spun at high speeds (up to around 30,000 rpm) at the end of the manufacturing process so that the individual rotor components are clamped together by centrifugal force. This clamping process is followed by a final balancing process, during which any imbalance present in the rotor can be corrected. However, if the rotor already contains excessive imbalance before the clamping process, this imbalance could cause damage to the rotating test bench. To prevent this, unbalance correction can be performed before the clamping process, but this does not eliminate the need for imbalance correction after the actual clamping process.

[0010] This is particularly problematic when the structural component being tested contains a high level of unbalance, as failure may occur due to stresses or forces in the shaft or component holder. Another drawback of the prior art is that rotors with large unbalances need to be balanced before the fixturing process, which means that several time-consuming work steps need to be performed. [Prior art documents] [Patent documents]

[0011] [Patent Document 1] German Publication No. 1 125 206 A [Patent Document 2] German Publication No. 102 06 950 A1 [Patent Document 3] German Patent No. 10 2011 087 909 B3 [Patent Document 4] German Publication No. 28 35 962 A [Patent Document 5] German Publication No. 693 08 430 T2 [Patent Document 6] German Publication No. 694 04 161 T2 Summary of the Invention [Problem to be solved by the invention]

[0012] The invention is based on the problem of realizing a means to prevent damage to the shaft or other components, especially in the case of large imbalances, and to eliminate the need for imbalance correction before the fixing process. [Means for solving the problem]

[0013] The above problem is solved by the features of claim 1. Preferred embodiments are set forth in the dependent claims.

[0014] According to the present invention, the above-mentioned problem is solved by providing an arrangement or device for a rotation test bench, which comprises a shaft that can be rotationally fixedly fixed to a drive unit via bearing elements, and a clamping holder that is provided for holding a rotor to be tested and can be coupled to the shaft in a rotationally fixed manner, characterized in that bending elastic spring elements are present between the drive unit and the shaft, and between the shaft and the rotor, in each case, designed to compensate for bending forces acting on the shaft and / or the clamping holder due to rotor vibrations. The spring element design absorbs any forces and stresses that could potentially cause damage to the shaft or the clamping holder. This means that even rotors with large imbalances can be tested on the rotation test bench without prior compensation, and the extra process of fixing rotor components during the rotation process is no longer necessary.

[0015] Another advantage of the present invention is that an elaborately constructed rotating test bench is not required and no large unbalance forces are generated. Furthermore, this solution prevents vibrations from being emitted into the environment by an unbalanced rotor in the form of structure-borne noise.

[0016] The spring element is advantageously designed in such a way that deformation of the spring element in the direction of the acting bending force is possible, which makes it possible to absorb and compensate for bending forces acting on the shaft or clamping holder, which in particular prevents damage to the shaft or clamping holder.

[0017] In one embodiment, the clamping holder is adapted to be at least partially flexible. Depending on the application, it may be advantageous to design the clamping holder itself at least partially as a bending-elastic spring element. This can be achieved, for example, by the clamping holder comprising a structural component that is coupled to the shaft in a force-transmitting manner and has slots, recesses, or similar bending-elastic elements that absorb bending forces acting on the shaft or the clamping holder. A similar arrangement can be provided for the bearing element, so that the bearing element is at least partially adapted to be bending-elastic and comprises slots or recesses.

[0018] Alternatively, the bending or flexible conformable spring element may be one that can be coupled to the clamping holder and bearing element, in other words, this preferred embodiment is not a structural component of the clamping holder or bearing element, but a separate, appropriately designed structural component that has the desired physical properties and that can be reversibly or irreversibly coupled to the bearing element and clamping holder.

[0019] Preferably, the bearing element and clamping holder as well as the spring element are provided with connection means which allow a structural connection, in particular a force-transmitting connection, with the spring element being manufactured as a separate structural component.

[0020] The spring element can be designed, for example, as a sleeve-like element mounted in a force-transmitting manner between the clamping holder and the shaft or between the shaft and the bearing element, the sleeve being designed to be flexible or at least to have a flexible section, which can be achieved, for example, by recesses, slots or integrated springs that absorb bending forces acting on the shaft, the clamping holder or the bearing element.

[0021] In one embodiment, the bearing element and / or clamping holder each comprises a spring element coupled to the shaft in a force-transmitting manner and extending or expanding radially from the shaft axis. The spring element can be provided, for example, as a circularly shaped, radially extending or expanding diaphragm or membrane, in particular with a central sleeve-shaped shaft bushing. In particular, the diaphragm or membrane is made of flexible metal.

[0022] The present invention further relates to a rotating test bench for testing rotors, comprising the above-mentioned configuration. The above-mentioned advantages and embodiments apply equally to the rotating test bench. Due to the advantageous design of the rotating test bench, rotors with imbalances can be rotated. The rotating test bench may also be called a component test bench in the sense of the present invention.

[0023] The present invention will now be described in detail with reference to an embodiment of the present invention shown in the drawings. [Brief explanation of the drawings]

[0024] [Figure 1] 1 is a schematic diagram of a rotary test bench according to the prior art; [Figure 2] 1 is a schematic diagram of a rotation test bench illustrating one embodiment of an arrangement according to the present invention; [Figure 3] FIG. 10 is a cross-sectional view of an embodiment of a configuration having additional structural components. [Figure 4] FIG. 1 is a cross-sectional view of an embodiment of a bearing element. [Figure 5] FIG. DETAILED DESCRIPTION OF THE INVENTION

[0025] FIG. 1 shows a schematic diagram of a prior art rotary test bench 1 on which a rotor 2 can be mounted as a test object to test, for example, the durability of the rotor 2 under rotational load. In addition to a housing (not shown), the rotary test bench comprises a drive 3 for supplying torque. The drive 3 can be designed, for example, as an electric motor. The torque of the drive 3 is transmitted to a vertically extending shaft 4 by coupling the shaft 4 to the drive 3 on the drive side via a torque-transmitting bearing element 5. The bearing element 5 can be, for example, a bearing, a coupler, or the like, in which a shaft journal of the shaft 4 engages.

[0026] The rotor end of the shaft 4 opposite the drive 3 is coupled to the rotor 2 in a torque-transmitting manner. The rotor 2 is held in a clamping holder 6 and clamped so that it cannot rotate. The clamping holder 6 can be designed in various ways depending on the shape and structure of the rotor 2. In this case, an exchangeable clamping holder 6 is advantageous in that it can be replaced depending on the test object. The clamping holder 6 can be coupled to the shaft 4 in a non-rotatable manner by a flange connection.

[0027] The damping system 7 is arranged on the shaft 4 between the bearing element 5 and the clamping holder 6 and is operably coupled to the shaft 4 in a housing-fixed manner. When the rotor 2 rotates, vibration excitation movements to be damped act on the shaft 4, thereby causing vibrations of the shaft 4 in the direction of the rotation radius. These vibrations can be damped by the damping system 7.

[0028] Due to the design of the rotating test bench 1, the axis of rotation of the rotor 2 being tested is not fixed. Due to the inherently freely suspended bearing, the rotor 2 is free to move so that it can freely choose its axis of rotation. This means that an unbalanced rotor 2 rotates around its axis of inertia instead of its geometric axis, which means that essentially no unbalance forces arise. Larger unbalances can lead to damage due to stresses and forces in the shaft 4 and clamping holder 6.

[0029] FIGS. 2 and 3 show an embodiment of the present invention, while FIGS. 4 and 5 show detailed views of the bearing element and clamping holder. Here, the rotary test bench 1 is shown without its housing, and the components are shown diagrammatically. According to the present invention, the known rotor motion model shown in FIG. 1 is extended by two bending or flexible elastic spring elements 8, one between the drive 3 and the shaft 4 on the drive side and the other between the shaft 4 and the rotor 2 on the component or rotor side. The elastic spring element 8 on the drive side can be provided as a metallic diaphragm or membrane 9 within the bearing element 5. The diaphragm 9 can be plate-shaped and extend or expand radially from the shaft axis. The diaphragm 9 merges into a tubular region 10 and supports the shaft 4 in a manner that transmits forces axially along the shaft axis. The diaphragm 9 can be, for example, flange-mounted on the bearing element 5. That is, the spring element 8 can be attached to the bearing element 5 by a flange connection. Deformations caused by large imbalances of the rotor 2 and transmitted from the shaft 4 to the bearing elements 5 are intentionally allowed so that low loads on the bearing elements 5 are achieved.

[0030] A similar or equivalent design can be chosen between the rotor 2 and the shaft 4, i.e. on the rotor side, in which case the spring element 8 can also be designed as a diaphragm and attached to the clamping holder 6 by means of a flange connection or the like.

[0031] However, it is also possible to design the spring element 8 as a component of the bearing element 5 or the clamping holder 6. For example, the clamping holder 6 for the holder of the rotor 2 can itself be designed to be at least partially flexible and thus provided as a spring element 8. An example of this design are recesses or slots 11 which extend transversely or perpendicularly to the shaft axis and which can be incorporated, for example, into the casing of the clamping holder 6 and which can give the clamping holder 6 bending elastic or flexible properties. Alternatively, the clamping holder 6 can be reversibly or irreversibly connected to the spring element 8.

[0032] The spring elements 8 are advantageously coupled to the shaft 4 in a structural and force-transmitting manner and absorb bending forces acting on the shaft 4. The defined stiffness of the spring elements 8 is advantageous. The use of the spring elements 8 according to the invention makes it possible, in particular, to rotate rotors 2 with large imbalances without internal stresses and forces arising in the flexible shaft 2 and / or without the clamping holder 6 reaching unacceptable values ​​and causing damage. The spring elements 8 do not have damping properties. Instead, the spring elements 8 according to the invention and their positioning ensure that deformations of the rotor 2 are accommodated, since the rotor 2 is self-aligned around the center of its gravity axis. For this reason, it is advantageous to design the system to be flexible enough to achieve low loads on the bearing elements 5 and the clamping holder 6. [Explanation of symbols]

[0033] 1 Rotating test bench 2 rotors 3. Drive unit 4 shafts 5 Bearing elements 6 Clamping holder 7. Damping System 8 Spring Elements

Claims

1. 1. An arrangement for a rotary test bench (1) comprising a shaft (4) which can be rotationally fixedly coupled to a drive (3) via bearing elements (5) and a clamping holder (6) which is provided for holding a rotor (2) to be tested and which can be rotationally fixedly coupled to said shaft (4), A configuration characterized in that there are bending elastic spring elements (8) between the drive device (3) and the shaft (4) and between the shaft (4) and the rotor (2), respectively, designed to compensate for bending forces acting on the shaft (4) and / or the clamping holder (6) due to vibrations of the rotor (2).

2. 2. The arrangement according to claim 1, wherein an adapted elastic spring element (8) is connectable to the clamping holder (6).

3. 2. The arrangement according to claim 1, wherein the bearing element (5) is connectable to a spring element (8) adapted to bend.

4. 2. The arrangement according to claim 1, wherein the bearing element (5) is adapted to be at least partially flexurally elastic.

5. 2. The arrangement according to claim 1, wherein the clamping holder (6) is adapted to be at least partially flexible.

6. 4. The arrangement according to claim 1, wherein each of the bearing element (5) and / or the clamping holder (6) comprises a spring element (8) coupled to the shaft (4) in a force transmitting manner, extending radially from the axis of the shaft and adapted to be axially flexible.

7. 7. An arrangement according to claim 6, wherein the spring element (8) is provided in the bearing element (5) as a circularly fitted diaphragm with a central tubular shaft through-hole.

8. The arrangement of claim 7 , wherein the diaphragm is formed from a flexible metal.

9. 6. An arrangement according to claim 5, wherein the flexurally elastic area of ​​the clamping holder (6) comprises recesses or slots (11) extending transversely to the axis of the shaft.

10. An arrangement according to any one of claims 1 to 9, wherein the spring element (8) is designed in such a way that deformation of the spring element (8) in the direction of the acting bending force is possible.

11. A rotating test bench for testing rotors, comprising the arrangement according to any one of claims 1 to 10.

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