HBM launch speed and torque measuring flange

Citation

(1999), "HBM launch speed and torque measuring flange", Industrial Robot, Vol. 26 No. 4. https://doi.org/10.1108/ir.1999.04926dad.002

HBM launch speed and torque measuring flange

HBM launch speed and torque measuring flange

Keywords Torque

HBM UK has launched a combined speed monitoring and torque measurement flange that is used to accurately measure torque, angular velocity and position in specialised automotive and industrial testing applications (see Plate 2).

Plate 2 HBM UK has launched a combined speed monitoring and torque measurement flange that is used to accurately measure torque, angular velocity and position.

The space­saving flange benefits engine, motor and gearbox test-rigs that operate with hydraulic or eddy current dynamometers. It is also suitable for testing and optimising pumps, by comparing the power fed into the pump with the throughput or head produced.

The device incorporates a slotted metal disk and an infrared transmitter that is capable of relaying both speed and directional information. The disk has 720 mechanical increments, which can be interpolated to 0.1 degrees accuracy.

The flange consists of an inner and an outer ring that are connected by four "I"­section spokes and housed inside a free-standing split-ring stator. The "I"­section spokes make the device up to 30 times stiffer than conventional torsional shaft transducers.

This high transverse strength means that the flange can also withstand large shear and bending forces from items that are attached directly to it. For example a pulley can be mounted directly to the torque flange for monitoring power transfer in a belt drive. This virtually eliminates the need for complex support bearings and expensive couplings, which makes for easy installation and quick set-up changes.

The output from a machine under test is applied to the inner ring and the outer ring is attached to a driver motor. Once under load, the outer ring is radially displaced relative to the inner ring. This displacement is proportional to the torque applied and is measured by strain gauges on the sides of the spokes.

An inductive telemetry system transmits the signals from the strain gauges to an amplifier and signal conditioning unit built into the base of the stator. This carrier frequency measurement and transmission arrangement eliminates interference effects from cables and mains hum and ensures a maintenance free lifetime of operation.

The device can be supplied in a number of different configurations including one simple variation that allows the user to provide 18-30V DC to the input and monitor the full range of torque by a +-10V DC output. This makes the unit less costly to set up with testing laboratories' existing hardware and software.

The flange has a bandwidth of 1,000Hz making it ideally suited to monitor dynamic signal transients. A typical dynamometer with a reaction arm torque measurement device on the other hand has a bandwidth of around 25Hz and is unresponsive to fast transient torques.

The new device is the latest addition to HBM's T1OF range of torque measurement flanges, now capable of measuring torque between 50Nm and 10,000Nm. The maximum permissible speed extends to 15,000 rpm, depending on the measurement range, and the unit can be supplied with fitted couplings on request.

For further information contact: Mike Johnson, HBM UK, Harrow Weald Lodge, 92 Uxbridge Road, Harrow Weald, Middlesex, HA3 6BZ. Tel: +44 (0) 181 420 7170; Fax: +44 (0) 181 420 7336; E-mail: mikej@.hbm-uk.co.uk; Web site: http://www.hbm.de