MXPA00008825A - Device for measuring the forces generated by a rotor imbalance - Google Patents

Abstract

The invention relates to a device for measuring the forces which are generated by the imbalance of a rotor (1), especially of an automobile wheel. The device comprises a measuring shaft (2) which is mounted in such a way that it can rotate about its axis (23) and to which the rotor (1) is fixed in order to carry out the measurement, and a mounting arrangement (3) for mounting the measuring shaft (2) on a stationary frame (6). The mounting (3) has dynamometers (4, 5) and an intermediate frame (7) on which the measuring shaft (2) is supported by a first dynamometer (4) and at least one virtual bearing (24). The intermediate frame (7) is supported on the stationary frame (6) by another dynamometer (5). This results in reduced forced dynamics compared to conventional machines with a floating mounting.

Description

DISPERSION FOR MEASURING THE FORCES THAT ARE PRODUCED IN THE ROTOR Description of the invention [State of the art] The invention relates to a device according to the preamble of patent claim 1 , as is known from DE 33 32 978 A1. In such a device for measuring the forces that occur due to unbalance in a rotor, it is known to mount the measurement shaft so that it can rotate around its axis in two bearing units arranged axially spaced apart from each other, which by means of dynamometers are supported n a hollow bearing box. This mounting of the measuring shaft is supported by a stationary frame. From EP 0 343 265 A1 s it is known to mount on a balancing machine a supporting support extending axially with respect to the measuring shaft, so that it can oscillate with respect to a stationary bastidoip, and to arrange between the supporting support the stationary frame, dynamometers that are arranged axially spaced one from the other. From DE 33 30 880 A1 it is known to support the support housing the bearing assembly for rotary movement of the measuring shaft in a stationary frame, through converters REF .: 122885 dynamometers axially spaced apart from each other. In a device for balancing the wheels of motor vehicles known from EP 0 133 229 A1, the measuring shaft is supported on a stationary frame, in a mounting comprising dynamometers. In order to achieve a dynamic compensation of the unbalance, two support planes are provided for mounting the measuring shaft, in which the dynamometers are also arranged. EP 0 058 860 Bl discloses a balancing machine for rotating bodies in which the measuring shaft is mounted so that it can rotate about its axis on a flat elastically flexible element disposed prependicularly to the machine bed. For this purpose the bearing for rotary movement of the measuring shaft is provided on the upper edge of the flat element. Deviations from the position of the flat element are detected through an arm that extends at right angles to the flat element, by dynamometers whose force application directions extend perpendicular to each other. In this one of the dynamometers records the static ratio while the other dynamometer captures the forces resulting from the dynamic imbalance that cause a torsion of the perpendicular plane element elastically flexible about a central line. From DE-AS 16 98 164 an oscillation measuring system (ultracritical) is also known, comprising a mounting for the rotor on leaf springs placed diagonally to one another, whose extensions form a virtual intersection point in one of the compensation planes of the rotor to be balanced. Through an intermediate plate, both leaf springs placed diagonally to one another rest against a base plate on perpendicularly upright leaf springs, arranged parallel to each other. By means of oscillation converters, the oscillations of the leaf springs resulting from an imbalance of the rotor are detected and transformed into the corresponding measurement signals. From DE-AS 10 27 427 and DE-AS 10 44 531 it is known to form joints by means of deburring points in elastic rods or leaf springs forming mounts capable of oscillating in balancing machines. The dynamometers that are provided at the measurement sites of the bearing planes of the known devices provide dynamometric signals which are proportional to the centrifugal forces resulting from the unbalance of the rotor and which generate the reaction forces measured by the dynamometers in the planes of support or on the measurement sites. In normal conventional measurement systems for wheel balancing machines, a cantilever mounting is customary for the measuring shaft and the rotor that is clamped on it. The conversion to both rotor compensation planes for the dynamic compensation of the unbalance is made based on the laws of leverage moments of the statics. Therefore, the forces that measure the dynamometers in both support planes are a function of the respective distance of the rotor to the two dynamometers. Due to the different length of these distances, in the case of a variation of the sensitivity in one of the measuring converters due to various influences, for example due to temperature, aging, impact, overload, jerking during transport, influence of humidity and the like result in a disproportionate error in the compensation masses that are calculated for the respective compensation planes. [Task of the invention] The task of the invention consists in creating a device of the type under consideration in which a variation in the sensitivity of a measurement converter due to the dynamics of forces previously explained, only has an insignificant impact on the compensation of the mass to be made in the compensation plans, for example by the compensation weights to be applied. In accordance with the invention, this task is solved by the distinctive features of claim 1 of the patent. For this purpose, the intermediate frame of inflexible configuration on which the measuring shaft rests on a support plane comprising a dynamometer, is supported on the stationary frame by another dynamometer. Both dynamometers are therefore in two support systems for the collection of imbalance with force measurement, being that each dynamometer is associated with one of both support systems. Both support systems are between the measuring shaft and the rigid frame, for example of the balancing machine in which the unbalance measurement and the imbalance compensation of a motor vehicle wheel are carried out. For this, the dynamometers can be found in different support planes but they are in the area of the rigid intermediate frame, or in a common support plane. By means of the configuration of both support systems mentioned above, at least one additional support having the property of a virtual fulcrum in another support plane is provided for the measuring shaft. It is also possible to provide two support planes of this kind with virtual support points of this type. The virtual support points can be included on both sides of the rotor to be measured. However, it is also possible to provide only an additional support plane comprising a virtual, flat support point which is preferably between both compensation planes of the rotor or also between the plane in which the dynamometers and the rotor are located. Preferably, the two dynamometers are arranged in a common support plane that extends perpendicular to the axis of the measuring shaft. The forces applied to the dynamometers as reaction forces are of parallel alignment, in particular coaxial to one another, and are in the common support plane. However, the dynamometers can be found within different support planes within the area of the axial extension of the intermediate frame. A preferred embodiment consists in supporting the measurement shaft in the intermediate frame in a first support plane comprising the dynamometer and in a second support plane comprising the virtual support point, and the intermediate frame in one of the Support planes are supported on the stationary frame by the second dynamometer and are also articulated to the stationary frame by means of a parallel pillar. The support plane comprising the virtual support point can be found between the rotor, in particular the wheel of the motor vehicle and the support plane comprising both dynamometers, or preferably between both planes of compensation of the rotor, in particular of the wheel of the automotive vehicle. Through a pair of support and joint counter-levers, the intermediate frame can be supported on the stationary frame at the respective ends of the supporting counter-levers. The measuring shaft can also be supported on the intermediate frame by means of a pair of support and joint counter-levers at the ends of the levers. The axes of the respective joints extend perpendicular to that plane in which the forces applied to the dynamometers and the shaft of the measuring shaft are located. The pair of supporting counter-levers serving the intermediate support frame in the stationary frame can simultaneously carry out the parallel driving to the stationary frame of the intermediate frame. For this purpose, the supporting counterpanes extend parallel to one another. However, it is also possible to arrange the supporting counter-levers angularly to one another, the vertex of the angle being preferably located on the axis of the measuring shaft or in the vicinity of this axis of the measuring shaft. The articulations of the supporting counter-levers are then in the corners of a trapezoid of the plan arrangement of the supporting counter-levers. By means of this arrangement, the virtual support point that is found on the outer side of the rotor is created. The virtual support point of the measurement shaft in the intermediate frame inside the rotor, in particular between the compensation planes, can also be formed by support counter-levers arranged angularly to one another, whose articulations are at the corners of . a trapezoidal horizontal plane of the arrangement of the supporting counter-levers. Preferably, the support counter-levers are configured as rigid flat elements to flex, for example sheet metal parts, castings, laminated flat pieces or the like, which in conjunction with the joints ensure that the application is carried out. of force desired to the dynamometers, which develops, for example, substantially linear and coaxial. The arrangement of the supporting counter-levers that is formed by the flat elements can be manufactured in one piece, the pianos being rigidly flexurally constructed and only the intermediate joints being elastically flexible, which substantially extend in linear form. The joints may be formed by weak points, for example, clearances between the individual flat elements rigid to flexion. By this, elastically flexible hinge axes are formed between the planar elements that are rigid to bending. By means of the corresponding parallel or angular arrangement, the desired virtual support points, which form support axes that extend linearly in the respective bearing planes, are then created as described above. The virtual support points are also the measurement sites taken into account by the computer of the balancing machine frame, which represent virtual measurement sites. [Examples] The invention is explained in more detail with reference to the embodiment examples. Shows: Fig. 1 a first embodiment; Fig. 2 a second exemplary embodiment; Fig. 3 a third embodiment; Fig. 4: a fourth embodiment; Fig. 5: a fifth embodiment; Fig. 6: a sixth exemplary embodiment; Fig. 7: a plan view on a measurement and assembly arrangement for the measurement shaft, as can be applied in the case of the modalities of Figs. 1, 3 and 5; Fig. 8: a perspective representation of the measurement arrangement of Fig. 7 seen frontally from above; Fig. 9: a perspective representation of the measurement arrangement of Figs. 7 and 8 seen laterally from above; and Fig. 10: a seventh embodiment. In the figures, a rotor 1 is illustrated in a schematic representation, which for measuring the unbalance is fixed to a measuring shaft 2 in known manner by fastening elements which are not shown in detail. The measuring shaft 2 is mounted so that it can rotate about its own axis in a stationary frame 6. This can be the machine frame of a wheel balancing machine. The assembly is carried out with the help of an assembly 3 which will still be described in detail, which also comprises dynamometers 4, 5. The assembly 3 may comprise a bearing 26 for tubular rotary movement in which the measuring shaft 2 is mounted so that it can rotate about its axis . The bearing 26 for rotary movement accommodating the measuring shaft 2 is immobile supported in a first bearing plane 8 in an intermediate frame 7 via the dynamometer 4. Additionally, by supporting counter-levers 13, 14 forming a pair of supporting counter-levers and extending angularly to one another a virtual support point 24 is created in another support plane 9. The support point 24 acts as an oscillating axis that extends perpendicular to the axis 23 of the measuring shaft 2 and perpendicular to the application direction of the force to the dynamometer 4, of the reaction forces resulting from the measurement of the unbalance. The supporting counter-levers 13 and 14 are connected at their articulated ends (articulations 19 and 22) to the intermediate frame 7 and articulated (joints 20, 21) to the bearing 26 for rotary movement of the measuring shaft 2. The articulation axes of the articulations 19 to 22 extend parallel to the oscillating axis that is formed in the virtual support point 24. The virtual support point 24 can be found between the rotor 1 and the support plane 8 in which the dynamometers 4 and 5 are located (Figs 1 and 2). However, the virtual support point 24 can also be found in the area of the rotor, in particular between the compensation planes 27 and 28, in which the compensation of the unbalance is carried out, for example by the application of pressure weights. compensation (Figs 5 and 6). The intermediate frame 7 is supported on the stationary frame 6 by the dynamometer 5. The dynamometer 5 can be arranged in the support plane 8 which is perpendicular to the measuring shaft 2. However, it is also possible to arrange the dynamometer 5 on another support plane displaced in the axial direction of the measuring shaft 2. The intermediate frame 7 is further supported in the stationary frame 6 by a pair of support counter-levers (supporting counter-levers 11 and 12). At the ends, the supporting counter-elements 11, 12 are connected in an articulated manner (articulations 15, 16) to the stationary and articulated frame 6 (articulations 17, 18 in FIGS. 1, 3, 5, 10 and 7 to 9). or the articulations 19, 22 in Figures 2, 4 and 6) to the intermediate frame 7. The intermediate frame 7 is configured as a stationary support bar or as a stationary and rigid support frame when flexed. In the embodiments of Figures 1 and 2 as well as 5 to 9, the supporting counter-levers 11 and 12 extend substantially parallel to one another and parallel to the axis 23 of the measuring shaft 2. Therefore, the supporting counter-levers 11 and 12 form a guide of connecting rods parallel with respect to the direction of application of the force to the dynamometer 5, substantially perpendicular to the axis 23 of the measuring shaft 2, of the reaction forces resulting from the measurement rotation of the imbalance. In the embodiments of FIGS. 3, 4 and 10, both support counter-arms 11 and 12 are arranged at an acute angle to one another, the vertex of which lies on the axis 23 of the measuring shaft 2 or in the vicinity of the axis 23. This vertex forms another virtual support point 25 in a support plane 10 which extends perpendicular to the measuring shaft 2 and is located on the external side of the rotor 1. In the embodiment of FIG. 10, the virtual support point 25 and the support plane 10 are located in an extension of the measuring shaft 2 drawn to points and lines which, with respect to the assembly 3 of the measuring shaft 2, develops in the opposite direction to the longitudinal extension of the measuring shaft 2. The support point 25 and the associated support plane 10 are located on the side remote from the rotor 1, referring to the assembly 3. The virtual support point 25 also has the characteristic of an oscillating axis that is perpendicular to the axis 23 of the shaft 2 of measurement and perpendicular to the application direction of the application of force to the dynamometers 4 and 5. In the represented embodiments, this application of force occurs in the support plane 8. To form the oscillating axis characteristic at the respective virtual support point 24, 25, the articulation axes of the joints 15 to 22 extend parallel to each other and perpendicular to the axis 23 of the measuring shaft 2 as well as to the direction of application of force of the reaction forces to the dynamometers 4 and 5 in the support plane 8. In the embodiments of Figures 3 and 4 the support planes 9 and 10 are created with the virtual support points 24 and 25 on both sides of the rotor 2, specifically on the inner side, and on the outer side of the rotor. The virtual support points 24 and 25 have the characteristics of virtual measurement sites. The forces L associated with the inner support point 24 are applied to the dynamometer 5 and the forces R associated with the support point 25 are applied to the dynamometer 4. The dynamometers produce the corresponding dynamometer signals L 'and R'. The fact that the virtual measuring points 24 and 25 also create virtual measurement sites is due to the fact that when a centrifugal force resulting from the unbalance of the rotor attacks in the left support plane 9, the dynamometer 5 emits a signal L ' of measurement proportional to the magnitude of this centrifugal force, while the dynamometer 4 does not emit any signal. When a centrifugal force R resulting from imbalance of the rotor attacks in the right outer support plane 10, only the dynamometer 4 emits a proportional measurement signal R 'while the dynamometer 5 emits no signal. This results in a cantilevered assembly in which the compensation planes 27 and 28 of the rotor 1 are located between the virtual measurement sites or virtual measurement planes that coincide with the support planes 9 and 10, as shown in FIG. Figs. 3 and 4. In the case of an action of the force between the support planes 9 and 10 as a result of rotor imbalance, the active support forces in these planes (virtual measurement plane) are divided according to the distances of the supports to the action point, and the dynamometers 4 and 5 emit the corresponding dynamometric signals. In the embodiment shown in FIG. 10, the virtual support point 24 in which a centrifugal force L resulting from the unbalance of the rotor can be activated is located in the support plane 9 between the two compensation planes 27, 28, preferably about half between both compensation planes 27, 28. The other 25 point of virtual support is, in relation to the assembly 3 of the measuring shaft 2, on the other side in the extension of the measuring shaft. In this, a centrifugal force R resulting from imbalance of the rotor acts. As already explained in the foregoing, the dynamometers 4 and 5 emit measurement signals R 'and L' proportional to the centrifugal forces R and L. In the embodiments of Figures 1 and 2 as well as 5 to 9, the external virtual support point is at infinity or at a relatively large distance of a few meters, for example between approximately 3 to 20 m and more, since a substantially parallel conduction for the frame is obtained by means of the supporting counter-levers 11 and 12 intermediate. If in these embodiments, a centrifugal force (L in Figs 1 and 2, S in Figs 5) is applied in the support plane 9 (virtual measurement plane) to the virtual support point (virtual measuring site). and 6) resulting from the imbalance of the rotor, this force is only detected by the dynamometer 5, which emits a proportional signal L 'or S'. The dynamometer 4 does not emit any signal. Independently of the distance of the centrifugal force applied, the dynamometer 5 will only emit a signal proportional to the magnitude of the centrifugal force by virtue of the parallel conduction of the intermediate frame 7.

Instead the dynamometer 4 will emit a measurement signal M 'which is not only proportional to the magnitude of the centrifugal force and consequently to the magnitude of the imbalance, but also to the distance from the point of application of force to the support plane 9 or well to point 24 virtual support. In the embodiments of Figures 1, 3, 5 and 10 as well as of Figs. 7 to 9, the support of the intermediate frame 7 in the stationary frame 6 with the help of the pair of support counter-levers formed by the supporting counter-levers 11 and 12, and the bearing of the tubular-shaped bearing 26 for the rotational movement of the shaft 2 of measurement with the aid of the pair of support counter-levers formed by the supporting counter-levers 13 and 14 is carried out consecutively seen in the axial direction of the measuring shaft 2. The pairs of supporting counter-levers of the embodiments of FIGS. 3 and 4 are inclined in the same direction. In the exemplary embodiment 11, 12 the inclination direction is opposite to the inclination direction of the pair 13, 14 of supporting counter-levers. In the embodiments of Figures 2, 4 and 6 the support of the support frame 7 in the stationary frame 6 and of the bearing 26 for rotary movement of the measuring shaft 2 in the intermediate frame 7 is effected with the respective pairs 11, 12 and 13, 14 of supporting counterpanes side by side or superimposed. In this it is possible that the articulations 17, 19 and 18, 22 coincide in the common articulations 19 and 22 in the intermediate frame 7, as shown in Figs. 2, 4 and 6. The supporting counterparts 11 to 14 can be formed by flat elements that are designed immobile and rigid to flex. The planar elements can be formed in one piece, the joints being formed by weak points in a linear fashion, for example in the form of cut-outs. As can be seen from Figs. 7 to 9, a clamping plate 33 can also be formed from the part forming the flat elements for the supporting counter-elements 11 to 14, which is an integral part of the clamping device 29. The holding plate 33 is firmly attached to the bearing 26 for tubular rotary movement, for example by welding. As an integral part of the clamping device 29, an angle support 34 can additionally be additionally provided, which is also firmly connected to the clamping plate 33 and to the bearing 26 for rotary movement, for example by welding. The upper angle support 34 is shown in the Figures. It is also possible to provide a lower angle support. The upper and lower angle supports can also be constituted by an angle in which the bearing 26 for rotary movement passes through an opening and is firmly connected to the angle support, for example by welding. By this, between the two joints 20 and 21, an immobile and rigid connection to the bending of the clamping device 29 is created with the bearing 26 for rotary movement. The joints 20 and 21 are between the two supporting counter-levers 13 and 14 and the holding plate 33. From the same piece from which the planar elements for the supporting counter-levers 11 to 14 are formed, fixing plates 37, 38 and 40, 41 can additionally be formed. The fixing plates 37, 38 are firmly connected to the stationary frame 6, for example by means of screw connections or otherwise. The fixing plates 37 and 38 form the fixing points for the counter lever arm formed by the supporting counter-levers 11 and 12, with which the intermediate frame 7 is supported on the stationary frame 6. Between the fixing plates 37 and 38 and the flat elements forming the support counter-levers 11 and 12, the joints 15 and 16 formed by the linearly weak points or the de-grooves are provided. The weak points have a concave cross section, in particular of semicircular shape.

Furthermore, from this one piece the two fixing plates 40 and 41 are formed which are firmly connected to the lateral surfaces of the intermediate frame 7, for example by means of bolted connections, welding or the like. Between the two fixing plates 40 and 41 and the supporting counter-levers 11 and 12, the joints 17 and 18 are formed by the weak points or slits. Between the flat elements that form the supporting counter-levers 13 and 14, the articulations 19 and 22 are formed by weak points or de-grooves. In this way it is possible to manufacture virtually all of the assembly 3 from a single piece, with which the measuring shaft 2 rests on the stationary frame 6 and preset the virtual measuring points and support points. The parallel conduction of the intermediate frame 7 in the stationary frame is obtained substantially due to the fact that the base lines of the cutouts 15, 17 and 16, 18 concave on both sides of the supporting counter-levers 11 and 12 are approximately in planes 35 parallels in which the stile function of both support counterparts 11 and 12 is obtained. The respective slots 15, 17 and 16, 18 are located on opposite surfaces of the supporting counter-levers 11 and 12 forming the flat elements. The support counter-levers 11 and 12 are inclined towards one another at an extremely sharp angle, although the guide of parallel connecting rods is obtained, as already explained, by the function of the upright of the parallel planes 35 and 36. By this it is possible to obtain the measuring arrangements corresponding to Figures 1 and 5. To obtain a measurement arrangement corresponding to Figure 3 it is possible to tilt the supporting counter-levers 11 and 12 so that they enclose a correspondingly greater angle between them. In order to be able to carry out the embodiment shown in FIG. 10, the rear ends of the supporting counter-levers 11 and 12 are directed against each other in Figures 7 to 9 .. The posterior de-slits or joints 15, 16 are closer to the axis of the measuring shaft 2 that the de-slits or joints 17, 18 above. As can also be seen from Fig. 8, the two dynamometers 4, 5 are arranged in a line of action, the dynamometer 4 being arranged between the bearing 26 for rotary movement and the inner side of the intermediate frame 7 , and the dynamometer 5 between the external side of the intermediate frame 7 or fixing plate 41 (Fig. 9) and the stationary frame 6. To drive the measuring shaft 2 an electric motor 30 is provided, which drives the measuring shaft through a transmission 31 by belts. The motor is mounted in bearing to the bearing 26 of rotary movement through a protruding arm 32. By means of this assembly, the disturbances coming from the motor-drive do not influence the result of the measurement. Seen in axial direction a compact assembly 3 is created for the measuring shaft 2 in the stationary frame 6. From this, in relation to the reduced force dynamics, in particular in the case of the cantilever mounting of the measuring shaft 2, a reduction in the influence of the sensitivity variations of the force receptors is derived, for example as a result of the various effects of temperature, aging, impact, overload, jerking during transport and humidity, less need for replacement of the dynamometers, readjustment of the measuring arrangement after transport and installation of the machine, lower maintenance costs, greater precision of the measurement, lower requirements regarding the resolution of the AD converter during the digitization of the analog measurement signals, and a large virtual distance between the measurement planes despite the compact form of construction. Despite the horizontal mounting of the measuring shaft, a reduced force dynamic similar to that of a measuring arrangement with two bearing mounting points on both sides of the rotor is obtained.

. { List of reference symbols) 1 Rotor 2 Measuring shaft 3 Mounting 4 Dynamometer 5 Dynamometer 6 Stationary frame 7 Intermediate frame 8 Support plane 9 Support plane 10 Support plane 11 Support lever 12 Support lever 13 Support lever 14 Support lever 15 Articulation 16 Articulation 17 Articulation 18 Articulation 19 Articulation 20 Articulation 21 Articulation 22 Articulation 23 Measurement tree axis 24 Virtual support point 25 Virtual support point 26 Bearing for rotary movement 27 Compensation plan 28 Compensation plan 29 Fixing device 30 Electric motor 31 Belt drive 32 Extending arm 33 Holding plate 34 Angle bracket 35 Parallel plane 36 Parallel plane 37 Fixing plate 38 Fixing plate 40 Fixing plate 41 Plate Fixing

Claims (25)

1. CLAIMS 1. Device for measuring forces that are caused by an imbalance in a rotor, with a measuring shaft mounted on a bearing for rotary movement so that it can rotate around its axis, on which the rotor for fixing the rotor is fixed. measurement, and a mounting of the measuring shaft comprising dynamometers, in a stationary frame, wherein - the assembly comprises an intermediate frame in which the measuring shaft rests on a bearing plane comprising a dynamometer, characterized in that the frame intermediate is supported on the stationary frame by another dynamometer, and because in addition the measurement shaft rests on the intermediate frame and the intermediate frame on the stationary frame, respectively a virtual support point formed by supporting counter-levers. Device according to claim 1, characterized in that the dynamometers are arranged in support planes within the region of the inflexible intermediate frame. Device according to claim 1 or 2, characterized in that the dynamometers are in a common support plane. Device according to one of claims 1 to 3, characterized in that the intermediate frame is supported on the stationary frame and the measuring shaft on the intermediate frame so that the forces applied to the dynamometers are in a plane and aligned in parallel, in particular coaxially with each other. Device according to one of claims 1 to 4, characterized in that the virtual support points are located outside the compensation planes. Device according to one of Claims 1 to 5, characterized in that the virtual support points form virtual measurement sites at their points of intersection with the measuring shaft. Device according to one of Claims 1 to 6, characterized in that the virtual support points are designed in a linear fashion and extend perpendicular to the measuring shaft. Device according to one of claims 1 to 7, characterized in that the measuring shaft is supported on the intermediate frame by a second bearing plane comprising the virtual support point formed by the previous supporting counter-levers, and the intermediate frame is It supports the stationary frame with parallel conduction and in the support plane comprising the external dynamometer. Device according to one of claims 1 to 8, characterized in that the assembly only comprises a virtual support point. Device according to one of claims 1 to 9, characterized in that a virtual support point is located between the compensation planes. Device according to one of claims 1 to 9, characterized in that a virtual fulcrum lies between the rotor and the stationary frame. 12. Device according to. one of claims 1 to 7, characterized in that two virtual support points are provided on both sides of the rotor. Device according to one of claims 1 to 12, characterized in that a virtual fulcrum is approximately halfway between the two compensation planes. Device according to one of Claims 1 to 13, characterized in that the virtual support point formed by a first pair of support counter-levers is located in an extension of the measuring shaft which extends in the direction of the measurement shaft assembly. contrary to the longitudinal extension of the measuring shaft. Device according to one of Claims 1 to 14, characterized in that the support points are located at the points of intersection of the extensions of the supporting counter-levers of the respective pair of support counter-levers. Device according to one of Claims 1 to 15, characterized in that the intermediate frame is supported on the stationary frame by means of a first pair of supporting counter-levers and their articulations, and the measurement shaft in the intermediate frame by means of a second pair of support counter-levers and their articulations, and in that the axes of the respective articulations extend substantially perpendicular to the direction in which the forces applied to the dynamometers are active. , and they are perpendicular with respect to the measurement tree. Device according to claim 16, characterized in that the supporting counter-levers of the first pair of support counter-levers are arranged in parallel or at an angle whose vertex is substantially on the axis of the measuring shaft. 18. Device according to claim 16 or 17, characterized in that the supporting counter-levers are formed by flexural rigid elements which are arranged between the associated joints. Device according to one of Claims 16 to 18, characterized in that the surfaces of the flat elements forming the support counter-levers are in the same plane as the axes of the associated joints. Device according to one of Claims 16 to 19, characterized in that the supporting counter-levers and the joints are manufactured in one piece, the joints being designed as weak points of linear extension. 21. Device according to. one of claims 1 to 20, characterized in that at least one of the two virtual support points is displaced with respect to the axis of the measuring shaft to that side in which the respectively associated dynamometer is located. Device according to one of Claims 1 to 21, characterized in that the support of the measuring shaft in the intermediate frame and the support of the intermediate frame in the stationary frame are located one after another or side by side, seen in the direction axial of the measuring shaft. 23. Device according to one of the * claims 1 to 22, characterized in that the bearing for rotary movement is firmly connected to a clamping device rigid to the bending at an axial distance from the bearing plane in which the dynamometers are located, and because the clamping device rests on the intermediate frame through two supporting counter-levers arranged at an angle with respect to each other. Device according to one of Claims 1 to 23, characterized in that the weak points forming the joints have a concave cross-section. Device according to one of Claims 1 to 23, characterized in that the weak points forming the joints are designed as linear perforations.