Since Australian Mining last reported on the Thompson Coupling, the Company now have advanced their unique invention into pilot production and testing.
The coupling, displaying the strength of a universal joint with all the attributes of true constant velocity promises to revolutionize drivelines in everything from motor vehicles and mining equipment to heavy machinery and industrial roller-mills.
One of the major hurdles in taking this ground braking technology to commercial production has been the lack of suitable test equipment and facilities. Because no previous coupling has been able to run under load at angles up to 20°, test equipment simply did not exist.
The Thompson Couplings Limited have purpose built a test facility in Orange NSW that will handle the demands of this new technology and provide critical data to design engineers.
Engineering director David Farrell gave the following overview to Australian Mining.
“In order to verify the design calculations we have constructed two special purpose engine/hydraulic dynamometers in our own premises,” he said.
These are designed to rotate the couplings at various speeds up to 3000rpm with a torque of 400 Nm. The power plant is a Nissan 6,9-L 180 Horsepower diesel engine. The Thompson coupling connects directly to the flywheel with the output connected to a hydraulic vane pump.
Hydraulic pressure created is controlled via a relief valve and its variable positioning allows any torque reaction to be imposed on the Thompson coupling up to the engines capacity. A specially designed cooling system keeps the oil flow at a constant 40°C in order to maximize performance.
The engine test facility is equipped with various safety devices including engine management and vibration control units.
The test facility allows for any articulation angle to be imposed on the Thompson Coupling up to its maximum design angle – currently 20°.
In operation the test facility will provide long-term fatigue results and endurance life figures for the Thompson Coupling bearings. Additionally competitor’s flexible couplings can be tested in the engine rig to provide direct comparisons with torque, speed and life.
Initial testing of the Thompson Coupling articulated at 15° and 50% full load resulted in bearing temperatures reaching no more than 32°C. A competitors CV joint articulated at the same angle and load conditions generated bearing temperatures of 298°C in just 11 minutes.
The operation of the engine test rig has been verified by Dr Kailash Sriram, managing director of IPACS, in Adelaide.
Using his latest triaxial vibration software, determination of the various signatures in the coupling, engine and pump were recorded. The software provides spectral, time signal and orbit analyses of the Thompson Coupling in part, his report stated:
The preliminary analysis of snapshot vibration spectra indicates that the Thompson constant velocity coupling has demonstrated its speciality and unique feature of absorbing very high input amplitudes from the driving unit, without generating frictional forces, and it does not raise the operating shaft or coupling temperature.
This should result in reduced maintenance, reduction of catastrophic failures and machine breakdowns. Due to its geometry of construction it seems to maintain constant velocity and dramatically reduces unbalanced forces that tend to disturb the operating vibration signature of ant drive train.
The inventors do have a highly enhanced product for both simple and complex machines.
The first pilot production models of the Thompson Coupling arrived at the Test Facility in December and will be thoroughly analysed during the early part of this year.
The Company are also interested in expressions of interest from anyone who would like to become involved in small scale field-testing. Thompson Couplings have the design capacity to tailor-make its couplings to suit one off applications such as large capacity pumps used extensively in the mining industry.
The main benefit of the coupling in this and many other applications is that it doesn’t rely on precision alignment between the driving source and the driven source, with up to 20° of angular misalignment possible. It means considerable savings in time and money at the installation stage and because reduced vibration maintenance is minimised.
Thompson Coupling Limited plans to establish itself as a design house rather than a manufacturing company.
As well as testing the coupling, the group is currently in the process of designing standard adapting flanges to allow the couplings to be retrofitted.