A flexible torsional compliant coupling is required in most engine testing applications. A properly sized torsional elasticity coupling will keep the main driveline resonance speeds below the idling speed (hypercritical operation). Furthermore the coupling provides a damping capacity in order to keep vibrations to a minimum.
The design developed by Voith (previously Küsel) uses a rubber mixture selected to achieve a highly flexibility torsional coupling to control engine testing vibrations. The advantage of the highly flexible couplings is that resonance speeds can be placed in a low speed range between engine start and low idle. The flexibility of the coupling also minimizes the shock associated with the engine firing. Components downstream from a properly sized coupling tend to have a longer life.
The highly flexible coupling is designed for connection to universal joint shafts; are characterized by their extremely short and simple construction; as well as by their insensitivity to larger bending angles of the universal joint shaft. The coupling design incorporate pilots on both sides to simplify attachment and to maintain rotational balance.
A typical engine test cell driveline arrangement is for the Voith Torsional coupling to be mounted to the engine flywheel. The other side of the coupling has the driveshaft. The driveshaft is mounting to the dynamometer. From this simple setup hundreds of driveling modifications are possible. Typical driveline modifications are to accommodate; engine overhung weight requirements; inline torque sensors; engine quick disconnects for end of line testing; bearing blocks to isolate the inertia mass; mounting the coupling on the dynamometer; etc.
For simpler systems a static resonance analysis predicts the first natural frequency. Using the basic resonance analysis and the stiffness associated with a coupling a robust driveline system can be developed. For other systems with multiple components, AEI in conjunction with Voith, can perform a specific Finite Element Analysis called a Torsional Vibration Analysis (TVA). The TVA shows both the predicted resonance frequency and any phase shifts in any of the components as the system speed changes. Component phase shift is associated with a high torsional stress driven by system resonance typically at a harmonic of the natural frequency.
In the attached PDF, “VOITH Technical Coupling Information
” outlines the engineering associated with how the torsional coupling manages the frequency and items that effect it’s function. For sizing of the coupling please fill out “VOITH Questionnaire
” and contact Application Engineering
, or call 269-639-7229 ext 260. If you would like to see the different styles of couplings to see which mounting attachments will fit within your driveline, AEI can send you an electronic version or a physical catalog.
The final determination of the suitable coupling demands a torsional vibration calculation and verification by Voith. Once Voith verifies all parameters are within limits, they will provide an engineering solution that will last the terms of the warranty.
Driveline component questionnaire - PDF