DE19959995A1 - Torque measuring system especially for use as static-dynamic torque measurement simulator - Google Patents

Abstract

The system has a drive shaft (4) with a brake disc (5), which is rotationally fitted on a bearing block (2). Torque can be applied to the drive shaft. At least one lever arm end is fixed to a force measuring cell (16,17), and supported in the hinge direction of a brake lever (14) hinged to the bearing block or the drive shaft. A brake unit (23) is fixed to the lever arm, for controlled dynamic and static braking of the brake disc. The brake disc is nonrotatably coaxially-connected to the drive shaft. The brake lever is preferably hinged coaxially to the drive shaft, The brake lever is at least one-sided. The braking force can be transmitted from the lever arm, as a reaction force, and is supportable at a pressure measuring cell, corresponding to the respective rotational direction as a pressure or a strain force. An indicating and evaluating unit is connected to the force measuring cell. The force measuring cell is preferably fixed to the bearing block.

Description

The invention relates to a torque measuring device as static / dynamic shear torque measurement simulator, especially for high torques Simulation of the screwing process of large screws and for testing and Calibration of torque setting for screwdrivers.

Screw connections, especially heavy screw connections must be tightened regularly with a specified torque. To a number of screwing devices are known.

Power wrenches with hydraulic motors or pneumati are generally known drives. A torque determination of the current tightening torque here takes place via a pressure and / or volume measurement in the drive system, whereby after a certain adjustable threshold is exceeded automatically according to a predetermined torque of the power wrench switches off.

A known power wrench (EP-OS 0 042 548) used for torque determine a separate, deformable component that coaxially off surrounds the power shaft of the power wrench. This torsionally flexible connection piece is made during the screwing process with increasing screw torque ment increasingly twists and turns a switch when a certain one  Deformation amplitude according to a certain tightening torque is reached. Electronic torque limiters are also connected with torsion shafts known, which by means of strain gauge arrangements in a bridge circuit work.

A well-known power wrench with electronic torque limitation (DE 43 07 131 A1) contains a drive unit with one of the drive units downstream planetary gear. This consists of an outer Ge gear housing and a planet carrier mounted therein, the tarpaulin ten gears in an inner ring gear of the gear housing as a sun gear intervention. The gearbox is open via a protruding support foot reaction forces can be supported externally. The power wrench is with one Strain gauge arrangement for detecting an at the output shaft part applied torque with a downstream, adjustable ejector teelektronik and a switch-off device for the drive unit.

It is necessary to use such screwdrivers for both type tests and Test individual devices before delivery, calibrate them and, if necessary, check them librate. For example, breakage tests are made regarding the durability of the Gear components carried out. It is also necessary to have calibrations for the Torque setting or shutdown. For this, test Stands used with torque measuring devices to which such Screwdrivers can be connected.

Known measuring devices and test benches contain a pre-calibrated one Torque measuring shaft, in connection via a torsion measurement a measurement signal is obtained with a strain gauge arrangement. Sol Measuring and testing devices are simple for smaller torques and can be produced in a functional manner. For larger torques increases due to the Torsionsmeßsystems the effort considerably and from a certain Such measuring and testing devices are practically not a torque  more usable.

The object of the invention is to provide a torque measuring device, which is easy to set up and works well, especially for the dyna mixed / static measurement of high torques is suitable.

This object is achieved with the features of claim 1.

According to claim 1, a drive shaft with a is on a bearing block rotatably, coaxially connected brake disc rotatably, being on the Drive shaft, the torque to be measured can be applied. At least one-sided brake lever is on the drive shaft or axially parallel to the drive shaft, preferably coaxial, pivotally mounted on the bearing block. The we at least one lever arm end is fixed in the swivel direction of the Brake lever supported force, preferably attached to the bearing block load cell connected. At least one lever arm is controllable Braking device for controlled dynamic and static braking of the attached by the drive shaft rotatably driven brake disc. The Braking force is pivoted as a reaction force by the at least one The lever arm can be extended and connected to the assigned load cell according to the respective direction of rotation as compressive force or tensile force for generation an assigned measurement signal can be supported. At least one force load cell, a display and evaluation unit is connected. The brake Force on the swiveling lever arm is a measure of that on the drive shaft applied torque, which is detected by the load cell and is represented by the connected display and evaluation unit.

This dynamic / static detection of the torque can be advantageous a screwing process of a nut until the Screw can be simulated. This is a customized test and an appropriate one suitable calibration for a screwdriver according to the actual on  possible with one screwing operation. The transition from dynamic up to the static measurement is by a time and pressure controlled braking the brake disc is reached.

Screwing operations with large required tightening and unscrewing torque elements are particularly needed in heavy engineering and power plant construction necessary, here there are safety-critical screw connections gene can, the exact adherence to a calculated and predetermined Tightening torque required. With the torque Measuring device is a screwing process, for example, up to a tightening Torque of 200,000 Nm can be simulated and a torque switch-off of a screwdriver can be precisely calibrated to a certain switch-off value.

The structure of the torque measuring device is simple and manageable. The torque measurement and thus a calibration of a screwdriver can be carried out with high accuracy, because on the one hand highly precise, pre-calibrated load cells are offered on the market and on the other hand a Recalibration of the torque measuring device in particular by opening bring a known weight, for example from 200 t to a force load cell instead of the brake lever load is easily possible.

Through the connected display and evaluation unit are off print measurement documentation possible. This unit can also be used for tax purposes measurement and, for example, automatically control a screwdriver and carry out measuring cycles and endurance tests according to prepro Perform programmable test conditions.

Basically, a torque measuring device is a single-armed lever order executable. The execution according to An is much more expedient Say 2 with a two-sided, preferably equal arm brake lever, at the radially protrude the lever arm ends of the brake disc and each with  connected to a load cell. Furthermore, each lever arm should have its own preferably have the same braking device.

This ensures that with a certain direction of rotation of the brake disc on a lever arm side the assigned load cell under pressure and the opposite load cell assigned to the other lever arm Train is claimed. The pressure measurement and tension measurement are different from each other independently, so that they are independently measured results can be evaluated and thus there is control and redundancy. At a mutually identical design of the lever arms and the brake device gen is the absolute value of the respective compressive and tensile forces equal. In addition, with a double-sided brake lever training an up construction achieved in the manner of a beam scale and the pivot bearing load reduced graces. The brake lever arrangement is preferably horizontal.

According to claim 3, a free end of the drive shaft comprises a connection part for connecting the output shaft of a screwdriver. The free end of the The drive shaft protrudes from the bracket so that the output shaft of the screwdriver can be connected quickly and easily. Further the bearing block preferably has in the region of the free end of the drive shaft a holder for the screwdriver and a reaction force support tongue on. This reaction force support is preferably as a stop trained to support a reaction force foot of the planet gearbox of a power wrench is adapted. The reaction force support is advantageously attached to the bracket so that high reaction moments can be supported in a simple and safe manner.

In principle, any braking system is suitable as a braking device that the Brake disc controlled braking dynamically and statically. In particular friction brake systems are suitable for this. So in one according to claim 4 preferred embodiment, the braking device a disc brake  storage device in which the brake lever arms of the braking device according to An Say 5 the brake disc on both sides in the manner of a brake caliper spread. Here are on the caliper legs in the direction of the Brake disc controlled removable brake pad attached.

According to claim 6, the brake disc is a total of approximately kas ten-shaped rectangular frame added. The long sides of this right Corner frames form this rectangular frame together with on the narrow sides Mens extensions arranged the lever arms of a two-sided Lever arrangement. Here are on the inside of the long sides Rectangular frame arranged the brake pad disks. They are further Long sides of this rectangular frame on the drive shaft swivel gela device. Overall, this results in a compact construction of the torque Measuring device with good accessibility and easy operation nung.

Basically, the braking device can be controlled in a variety of ways. According to claim 7, the braking device is hydraulic and / or pneumatic and / or electrically continuously by hand and / or by a control direction of the evaluation unit from a dynamic braking with increasing braking force can be controlled up to static braking.

In an advantageous further development according to An depending on the circumstances saying 8 is at least a section in the power flow of the drive shaft as kali combustible torque measuring shaft. So that's the application spectrum of the torque measuring device expanded again. For example It can be a dynamic / static detection of the torque and thus a Simulation of a screwdriving process using only the torque Measuring shaft are carried out without the brake lever on the Load cells occurring measured values are observed. This is in use a standard torque measuring shaft up to torques of  approx. 50,000 Nm possible. On the other hand, for very accurate calibrations both the measured values from the two load cells as well as from the rotation torque measuring shaft can be used at the same time, here a triple Check by comparing three independently generated measurements valuation is possible. For high torques with the torque measurement wave may no longer be detectable, then the detection is over the pivoting lever arrangement and the load cells knows in any case ter available.

In a multi-part embodiment of a drive shaft according to claim 9 it is simply possible to use a commercially available torque measuring shaft as a shaft part use. A simple, compact arrangement results when a Flange connection is made directly to the brake disc, before preferably the connecting flange as twistable and metrologically in its shape change detectable measuring flange is used.

In a manner known per se, the torque Measuring shaft as a torsion shaft and / or in particular for larger torques the connecting flange are designed as a measuring flange, with a gate sion is preferably detectable via a strain gauge arrangement. The torsion measurement data can easily be measured by a two-part measuring circuit from a first circuit part on the rotating torsion shaft to one Transfer the stationary circuit part attached to the bearing block without contact be. The measurement data available there can then be one Evaluation and control circuit are supplied.

The invention is explained in more detail with reference to a drawing.

Show it:

Fig. 1 is a schematic front view of a torque measuring device,

Fig. 2 is a schematic plan view of the torque measuring device of Fig. 1,

Fig. 3 is a schematic sectional view taken along line AA of Fig. 1, and

Fig. 4 is a view corresponding to Fig. 3 with additional torque measuring shaft.

In FIG. 1, a torque measuring device is schematically illustrated 1, the large for simulating the Anschraubvorgangs screws and used for test and calibration of the torque setting of screwing devices as a static / dynamic torque measurement simulator for large torques.

These torque measuring device 1 comprises a bracket 2, which is designed as identical parts in a central area two, one after the other spaced apart bearing leg 3 has. In these bearing legs 3 , as shown in FIG. 3, which shows a section along the line AA of FIG. 1, a drive shaft 4 is rotatably supported via ball bearings 6 . With this drive shaft 4 , a brake disc 5 is non-rotatably and coaxially connected, the brake disc 5 being spaced from the bearing legs 3 between them. The diameter of the brake disc 5 is approximately 85 cm.

As can be seen in particular from FIG. 2, which shows a top view of the torque measuring device 1 , the brake disc 5 is accommodated in a box-shaped rectangular frame 7 . The long sides 8, 9 of this rectangular frame 7 together with the narrow sides 10, 11 of the rectangular frame 7 lever arms 12 formed, 13 is a two-sided lever fourteenth The long sides 8 , 9 of the rectangular frame 7 are, as can be seen from FIG. 3, pivoted on the drive shaft 4 via ball bearings 15 . Thus, the brake lever 14 is also pivotally mounted on the drive shaft 4 .

The two lever arms 12 , 13 designed as identical parts each extend away from the brake disc 5 to a load cell 16 , 17 , which are connected to the bearing block 2 at the edges in the illustration in FIG. 1. The length of the lever arms 12 , 13 from the drive shaft 4 to the load cells 16 , 17 is approximately 1 m. The two lever arm ends 18 , 19 are each connected in a fixed manner in the pivoting direction of the brake lever 14 to the corresponding load cell 16 , 17 . The load cells 16 , 17 can absorb forces up to 200 t.

As shown in FIG. 2, the lever arm ends 24 , 25 of the lever arms 12 , 13 on the brake disc side overlap the brake disc 5 on both sides in the manner of a brake caliper, with the lever arm ends 24 , 25 being displaceable in a controlled manner in the direction of the brake disc 5 on the brake caliper legs Brake pad disks 20 of a disk brake pad device 23 are attached. The disc brake lining device 23 , which is only shown in broken lines in FIG. 1, can be controlled manually by means of a hydraulic system 26 .

As can be seen in particular from FIGS. 2 and 3, a free end of the drive shaft 4 comprises a connection part 27 for the coaxial connection of the output shaft 28 of a screwing device 29 . As can be taken ent only in FIG. 3, the bearing bracket 2 is a holder 30 for the screw device 29 and attached to the bracket 31 a stop action force for supporting a foot 32 of the Re Schraubgeräts 29.

The operation of the torque measuring device 1 as a static / dynamic torque measuring simulator is described below with reference to FIGS . 1 to 3:
At the beginning of the measurement, a torque of up to 200,000 Nm to be measured is applied to the drive shaft 4 of the torque measuring device 1 and thus the brake disc 5 via the output shaft 28 of the screwing device 29 .

To measure the torque, the brake disk 5 is then braked with the braking force to be increased by actuating the brake lining device 23 via the hydraulics 26 . The braking force is reacted as a reaction force by pivoting the lever arms 12 , 13 of the brake lever 14 and supported on the associated load cells 16 , 17 , where the torque can be detected both dynamically and statically.

Depending on the direction of rotation of the drive shaft 4 and the brake disc 5 , the reaction force is supported on the load cell 16 or 17 as a compressive force or tensile force, as shown in FIG. 1 by the arrows 33 pointing in the direction of pull or the arrows 34 pointing in the direction of pressure . To the load cells 16 , 17 , a display and evaluation unit (not shown here) is also connected, with which an evaluation of the measured torques is possible.

In FIG. 4 is a development, the only torque shown in FIGS. 1 to 3 ment measuring apparatus 1 shown integrated in the in the drive shaft 4 is a Drehmo ment measuring shaft 36 and is connected by means of a measuring flange 37 with the brake disc 5.. Specifically, the drive shaft 4 consists of the brake disc 5 with a connected bearing journal to the rear bearing and a measuring flange 37 as a connecting flange with a connected bearing journal with a connecting part 27 at the end . The torque measuring shaft 36 comprises, in a manner known per se, the measuring flange 37 , the torsion of which is detected electrically when a torque is applied via a strain gauge arrangement (not shown). For this purpose, a measuring circuit 38 is provided, which consists of a first, with the torsion shaft rotating scarf device part 39 and from a stationary arranged on the bearing block 2 scarf device part 40 . A contactless data transmission takes place between the two circuit parts 39 , 40 . From the stationary circuit part 40 , the acquired torque data are forwarded by means of a connecting line 41 to an evaluation and control circuit, not shown. In this embodiment, a further integrated torque detection system is therefore available as a torque measuring shaft for a separate or for a combined use with the lever measuring system.

Claims (10)

1. Torque measuring device, in particular as a static / dynamic torque measuring simulator for large torques for simulating the screwing-on process of large screws and for testing and calibrating the torque setting of screwing devices,
characterized by
that a drive shaft ( 4 ) with a rotationally fixed, coaxially connected brake disc ( 5 ) is rotatably mounted on a bearing block ( 2 ), the torque to be measured being able to be applied to the drive shaft ( 4 ),
that an at least one-sided brake lever ( 14 ) is pivotably mounted on the bearing block ( 2 ), preferably coaxially with the drive shaft ( 4 ), or on the drive shaft ( 4 ),
that the at least one lever arm end ( 24 , 25 ) is connected to a load cell ( 16 , 17 ) which is supported in a stationary manner in the pivoting direction of the brake lever ( 14 ) and is preferably attached to the bearing block ( 2 ),
that on the at least one lever arm ( 12 , 13 ) a controllable braking device ( 23 ) for controlled dynamic and static braking from the by the drive shaft ( 4 ) rotatably driven brake disc ( 5 ) is attached, the braking force as a reaction force by the at least one pivotable Lever arm ( 12 , 13 ) can be extended and supported on the associated load cell ( 16 , 17 ) according to the respective direction of rotation as a compressive or tensile force, and
that a display and evaluation unit is connected to the at least one load cell ( 16 , 17 ). 2. Torque measuring device according to claim 1, characterized in that a two-sided, preferably equal arm brake lever ( 14 ) is used, both lever arm ends ( 24 , 25 ) project radially beyond the brake disc ( 5 ) and each with a load cell ( 16 , 17 ) are connected and both lever arms ( 12 , 13 ) each have a preferably identical braking device ( 23 ). 3. Torque measuring device according to claim 1 or claim 2, characterized in that
that a free end of the drive shaft ( 4 ) comprises a connecting part ( 27 ) for the coaxial connection of the output shaft ( 28 ) of a screwing device ( 29 ), and
that the bearing block ( 2 ) has a holder ( 30 ) for the screwing device ( 29 ) and a reaction force support, preferably a stop ( 31 ) for supporting a reaction force foot ( 32 ) of the planetary gear of a power wrench. 4. Torque measuring device according to one of claims 1 to 3, characterized in that the braking device is a disc brake lining device ( 23 ). 5. Torque measuring device according to claim 4, characterized in that the brake lever arms ( 12 , 13 ) overlap the brake disc ( 5 ) on both sides in the manner of a brake caliper and controlled on the brake caliper legs in the direction of the brake disc ( 5 ) as a braking device relocatable brake pad disks ( 19 , 20 , 21 , 22 ) are attached. 6. Torque measuring device according to claim 5, characterized in that
that the brake disc ( 5 ) is received in a box-shaped rectangular frame ( 7 ) whose long sides ( 8 , 9 ) together with extensions on the narrow sides ( 10 , 11 ) form the lever arms ( 12 , 13 ) of a two-sided lever arrangement,
that the brake lining disks ( 19 , 20 , 21 , 22 ) are arranged on the inner sides of the long sides ( 8 , 9 ), and
that the longitudinal sides ( 8 , 9 ) are pivotally mounted on the drive shaft ( 4 ). 7. Torque measuring device according to one of claims 1 to 6, characterized in that the braking device ( 23 ) hydraulically and / or pneumatically and / or electrically continuously by hand and / or by a control device of the evaluation unit from a dynamic braking with increasing Braking force is controllable up to a static braking. 8. Torque measuring device according to one of claims 1 to 7, characterized in that at least one section in the power flow of the drive shaft ( 4 ) is ausgebil det as a calibratable torque measuring shaft ( 36 ). 9. Torque measuring device according to claim 8, characterized in that the drive shaft ( 4 ) is formed axially in several parts, of which a shaft part is the torque measuring shaft ( 36 ) with a bearing journal, which is connected to the brake disc by means of a flange ( 37 ) ( 5 ) is connected and the other shaft part is formed by the brake disc with an attached journal. 10. Torque measuring device according to claim 8 or claim 9, characterized in that
that the torque measuring shaft ( 36 ) is designed as a torsion shaft and / or the connecting flange ( 37 ) to the brake disc is designed as a twistable measuring flange, wherein a torsion can preferably be detected via strain gauges in a bridge arrangement, and
that an electronic measuring circuit ( 38 ), which preferably interacts with the strain gauge arrangement, consists of a first circuit part ( 39 ) rotating with the drive shaft ( 4 ), which provides measurement data and a stationary, preferably connected to the bearing block ( 2 ) second circuit part ( 40 ), with which measurement data from the first circuit part ( 39 ) can be received wirelessly, which data can then be fed to an evaluation and control circuit.