When it comes to gearbox test rigs deployed in the automotive and aerospace industries, one thing is certain - there is no margin for failure. A test rig or system that is unreliable or produces erroneous results can have serious consequences to development programmes where designers and research and development engineers are under intense pressure to deliver next-generation solutions to a demanding customer base.
Gearbox test rigs come in many different configurations, depending on the type of transmission being tested. However, most share a common requirement, namely the need for electromechanical components such as high-speed servomotors, inverters and linear motors.
A case in point can be seen at BIA, a French-based industry leader in the design, development and manufacture of test equipment and systems for customers in the aerospace, industrial and automotive sectors. The company has been collaborating with specialists at Parker for a number of years, with the outcome that BIA is now able to combine specific elements and components of its test rigs into completely bespoke, integrated systems that offer higher reliability and performance.
“We very much benefit from Parker’s wide product offering that helps us to efficiently source high quality and reliability components and systems, which finally contribute to BIA’s global success. We appreciate the very constructive spirit with which the dialogue with Parker is conducted."
Olivier Carlier. project leader at BIA
Parker works closely with customers such as BIA to help define the components required for each individual simulation and test system. Here, the company’s extensive portfolio assists in sourcing high quality, reliable products and systems. Products such as Parker’s high-speed servomotors, for example, are adopted widely in gearbox test rigs for the efficiency of their cooling systems, as are Parker linear motors, chiefly as a result of their positioning accuracy.
Beginning with Parker’s brushless, permanent-magnet, high-speed MGV servomotors, these offer the capability to simulate a combustion engine in conjunction with a vehicle’s manual gearbox. Of particular note, MGV motors benefit from water cooling, which in turn permits their dimensions and operating noise to be minimised. Furthermore, the low inertia of the MGV allows for highly dynamic acceleration and deceleration, while in order to achieve maximum precision, motor speed and torque are controlled in a closed loop, permitting the servomotor to be used for simulations in both urban traffic and race conditions.
Parker MS asynchronous motor are also popular for gearbox testing applications. The reason stems from the fact that the MS can deliver 10,000 rpm at 500 kW, which is ideal for gearbox duration testing – a task which requires a constant, medium speed without acceleration.
On the subject of transmission endurance tests, Parker ETT linear motors are often deployed (including at BIA) to actuate the gear lever and engage gears. Here, the rectangular rod configuration connected to ETT cylinders simulates movement through the standard H-slots of the gear lever. ETT linear motors have a high positioning accuracy of 0.5 mm, along with repeatability of 0.05 mm.
Also worthy of mention, Parker AC890 inverters have been developed to achieve optimum performance levels with both asynchronous motors (MS) and synchronous servomotors (MGV), and are able to operate in both motor and generator modes. This functionality can be exploited during gearbox tests: one motor can be connected to the gearbox input, just like a diesel engine, while two other motors (operating in generator mode) can be linked with the output of the gearboxes to simulate rotating wheels. This power generation gives full grid energy recuperation and can enable significant energy savings too.
Article contributed by Michel Finck, market development manager, Electromechanical & Drives Division Europe.