The Torque measuring shaft is a special one sensor technology for measuring torque in rotating systems such as drive shafts, Engines or gearboxes. They are used in automobiles and industrial drives. Our article presents the latest developments and technologies that make these measurement waves more efficient and user-friendly.

Contents

• First wireless torque measurement for drive shafts
• Torque measuring shaft determines four measured variables simultaneously
• Bearingless torque measuring shaft for the small torque
• FAQ

First wireless torque measurement for drive shafts

15.01.2024/XNUMX/XNUMX | With the Kitorq DS Kistler developed the first torque measuring system for vehicle axle shafts with wireless data transmission. The transmitter is located above the strain gauge sensor and can be attached to the drive shaft using an adapter. This means the unit can be easily removed, for example if you B. the Batteries change or charge or change the transmitter to another one Vehicle would like to attach.

The receiving unit processes the input signals from two transmitters and also receives the signal from the CWPT type wheel pulse generator. This means that wheel speed and acceleration can be measured directly Vehicle performance to calculate.

When developing Electric Cars allow engineers to measure torque on drive shafts, including the efficiency of the entire drive train recuperation better to calculate. Kistler's new solution significantly simplifies these measurements.

The cableLoose torque measuring system consists of two transmitting units and one receiving unit. With the special design, two half shells enclose the drive shaft. While the telemetry half-shell sends the data to the integrated evaluation electronics, the replaceable battery is located in the second shell.

Adapter allows reuse of the transmitter unit

With an innovative adapter sleeve, the system offers quick and easy installation on different drive shafts, making it reusable for multiple vehicles - a clear advantage over conventional disposable solutions. The six basic variants half shells cover most drive shaft diameters of modern cars, regardless of the drive concept.

The precise adaptation of the adapter to the respective drive shaft ensures safety perfect fit the transmitter unit and enables the automatic detection of the waves to be measured. In addition, the system ensures a power failure bridging of up to 30 s and offers various digital data outputs, including CAN, DTI and Ethernet.

The compact receiver unit processes torque and temperature signals from up to two transmitters, while a total of six transmitter units can be used for simultaneous measurements on up to six shafts.

Torque measuring shaft determines four measured variables simultaneously

July 06.05.2021, XNUMX | KTR Systems has one Torque measuring shaft which for the first time determines the angle and direction of rotation in addition to torque and speed. The Dataflex series covers a measuring range from 50 to 20.000 Nm. It is based on a measuring principle using strain gauges and is equipped with the latest electronic components. With a sampling rate of 10 kHz, the transducer enables the measurement of dangerous torque peaks in a highly dynamic manner Drives.

The insensitive to interference Data transmission the torque transducer works digitally with a resolution of 24 bits and has a measurement inaccuracy of only 0,1% of the final value. The signal output is extremely low-noise. To measure the speed, an encoder delivers two signals phase-shifted by 90 degrees with a resolution of 360, 450 or 720 pulses per revolution. The practical transducer is not an optional extra but is included in the standard scope of delivery.

Shaft coupling for backlash-free torque transmission

Due to the high resolution, the speed signal of the torque measuring device is also suitable for determining the current Angular position the wave. An integrated f / U converter ensures that a DC voltage signal is output in addition to the usual square-wave signals. Another output shows the direction of rotation of the drive shaft.

Torque measuring shafts for integration into the drive

For integration in the drive, the Dataflex comes with the torsionally rigid servo as standard Multi-disc clutches Radex-NC combined. This connection is particularly suitable for drives in which highly dynamic torque peaks occur. It is also possible to combine them with others Couplings like the backlash-free Rotex GS shaft coupling.

Rigid coupling for different shaft diameters

The can be used to connect external devices Torque transducer Simply combine it with the DF2 connection housing. The torque output can be filtered in five levels so that short torque peaks on the display can be reduced. On the connection housing there are connections for speed measurement, direction of rotation signal and DC speed signal. All outputs on the sensor are compatible with measurement data acquisition cards as well as PLC controls.

Versions of the torque measuring shaft

There are currently five versions of the torque sensors:

• Dataflex 16 for torques up to 50 Nm
• Dataflex 32 for torques up to 500 Nm
• Dataflex 42 for torques up to 1000 Nm
• Dataflex 70 for torques up to 3000 and 5000 Nm
• Dataflex 110 for torques up to 20.000 Nm

Bearingless torque measuring shaft for the small torque

April 21.04.2021, XNUMX | Manner offers a bearingless standard Torque measuring shaft Assortment. Compared to the classic slip ring torque measuring shaft, these torque sensors measure the torque in the drive train without any wear or shunted forces. Even a speed of up to 160.000 min^-1 can thus be implemented - without any annoying noises Warehouse.

Especially when it comes to accuracy, the bearingless shaft clear advantages over a mounted measuring shaft. The basic accuracy of Manner's measuring shafts is better than 0,05%. In addition, further compensations can optionally be integrated. In this way, influences such as the modulus of elasticity on the torque can be eliminated.

Measuring torque with sensors inside the transmission

The torque transducer also has a small moment of inertia and can be easily inserted into the Wave strand embed. By default, this can be done via inexpensive clamping Couplings take place. Expensive storage is no longer necessary. The structure for test benches is simplified. That saves costs.

Torque measuring shaft for the test bench

The torque transducer therefore offers enormous advantages for measurements on the test bench. Manner would like to go into two versions of the torque sensors in particular: the standard torque measuring shaft and the customer-specific one Test stand shaft for particularly small torques.

In the standard range there is the torque measuring shaft from 1 Nm to 1000 Nm with extremely low moment of inertia and high speed strength. The integration into the shaft train takes place here by inexpensive Clamping couplings or via bellows couplings.

Optionally, a Speed ​​acquisition can be integrated with high resolution. In another standard variant, the torque is transmitted at both shaft ends via a feather key. The basic accuracy of the Measurement Technology is 0,05% based on the measuring range value. Depending on the version, the measurement technology is up to 156.000 min^-1 and can be used for temperature measuring ranges from -40 ° to +160 ° C.

If the integration of a standard torque measuring shaft is impossible, Manner offers customer-specific components. The construction and layout of the measuring point as well as the Production the torque measuring body is done in-house. With this solution, complex integrations into the shaft train that are unfavorable for measurements can be avoided.

Technology of torque transducers

The transducers work inductively with a patented transmission process. High data rates are safely inductive even with frequently occurring electrical interference fields Engines transfer. 

The torque signal delivers the tried and tested Strain gauges (DMS) technology. A high-precision, digital and remotely programmable measuring amplifier on the shaft amplifies, conditions and digitizes the measurement data with 16-bit resolution. The speed is measured with a Hall sensor or Laser sensor detected.

Inductive sensor detects carbon for the first time in the world

This allows large distances between the measuring shaft and Speed ​​sensor. The torque and speed data can be sent in analogue via frequency, voltage or current output as well as digitally by means of CAN, Ethercat, Ethernet or USB output. The contactless transmission is characterized by an antenna gap of up to 10 mm (optionally 25 mm). As a result, assembly is absolutely problem-free even in the radial and axial directions. There are no collisions due to vibrations. 

FAQ

What is a torque measuring shaft?

An Torque measuring shaft is a precision instrument used to measure torque (rotational force) directly in a shaft. It is equipped with sensors that detect the torsion or distortion of the shaft under load and thereby determine the torque transmitted.

When do I use torque measuring shafts and when do I use torque measuring flanges?

Während measuring waves offer an integrated, space-saving solution for dynamic and high-speed systems measuring flanges Robust and flexible for use in a wide range of stationary applications where direct integration into the shaft is not possible or desired. Whether you use a torque measuring shaft and a torque measuring flange depends on the application, the installation conditions and the expected loads:

Torque measuring shafts:

• Application: Ideal for applications where available space is limited or the measurement needs to be integrated directly into the shaft.
• Advantages: They provide precise, direct measurement of torque within the shaft and are suitable for applications with dynamic loads and high speeds.
• Examples of use: Common in automotive development, test benches or applications where shaft dynamics are critical.

Torque measuring flanges:

• Application: Suitable for applications where installation between two machine parts is possible, such as between the engine and gearbox.
• Advantages: Measuring flanges are robust and offer high accuracy. They are particularly suitable for stationary applications or for monitoring machines.
• Application examples: Commonly used in industrial plants, manufacturing processes or test facilities where reliable monitoring of torque is required.

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