As the power to weight ratios of modern engines increase, crankshafts are becoming increasingly light. This has now brought about the phenomenon of rigid body vibrations of the crankshaft to thefore.These vibrations are not due to the twisting and un-twisting of the crankshaft, however they are the result of the flywheel and crankshaft nose being in the same phase (direction). These modes are present in the lower harmonics (usually 2nd and 4th). This results in a stop and go effect at the nose of the crankshaft. This overloads the (FEAD) auxiliary drives such as the belt & belt tensioners, power steering pump etc. To mitigate the negative effects of rigid body mode vibrations on front engine accessories, a device called the ISOLATOR is used, which essentially consists of a highly flexible torsional spring that is restrained to the torsional mode of motion. The stresses on the rubber in this product are especially stringent. Vibromech has experience in the design and high volume production of this complicated product that combines the latest in design, production methods and technology.
The DAMPOLATOR(TM) is the latest generation of crankshaft vibration reduction devices. It combines the functionality of both the isolator and the harmonic detuner (TVD). It is a comprehensive solution to all torsional modes of vibration of the crankshaft. It essentially consists of a harmonic detuner (TVD) that is integrated into an isolator. Thus it serves the functions of reducing both crankshaft twisting (high order torsional modes) and speed variations (low order rigid body modes). The harmonic detuner reduces vibration by modifying the mass elastic system of the crankshaft and the isolator isolates the front engine accessories from excessive speed variation. This product combines the functionality of two different and independent functions. The design and development of a dampolator is an involved task because it brings together greatly different requirements and technologies to engineer and manufacture the product. This is the high end of rubber damper design and Vibromech is capable of developing this product by the application of the latest in material forming, machining technology and design and validation methodologies.
Vibromech makes India's premier VISCOUS DAMPERS. Our technology been developed on the basis of years of research in mechanical vibration engineering. They work by dissipating energy that is generated during torsional vibration. Viscous dampers are essentially of two types, viscous shear dampers and paddle wheel dampers. Viscous shear dampers are used in medium duty applications such as trucks, tractors and generators. Sophisticated production processes are used in the manufacture of viscous dampers. Wide use proves product reliability. Vibromech Viscous Shear (Friction) Dampers are widely used in some of the leading makes of engines built worldwide. They are designed to offer the optimum level of vibration damping with minimum power loss in the transmission system, throughout the normal operating speed range. This is the top end of devices to mitigate torsional vibration and VESL has the capability to design and manufacture these products.
A patented process, using special high-resilience rubber, is used to manufacture Vibromech dampers. We are winners of the prestigious President's award for import substitution. This was for our pioneering efforts in developing the technology indigenously. We have been through several rounds of innovation in the product design and manufacturing methods. The rubber hysteresis damper works by modifying the mass elastic system of the engine and effectively cheats the engine from exhibiting high amplitudes of torsional vibration within the engine operating range. HARMONIC DETUNERS are a highly cost-effective means for torsional vibration reduction in low to medium power engines.
The preferred choice of OEMs, Vibromech Rubber Hyteresis type vibration Dampers not only ensure freedom from breakdown or failure of crankshafts but also prevent structural / mechanical damage to the engine system from vibrations, throughout the normal speed range.
The result Maximum operational efficiency and increased service life of the powertrain.
Paddle Wheel Type
Backed by the years of dedicated research in vibration engineering, Vibromech - paddle wheel dampers are internationally accepted.
Product Reliability In heavy duty engines like prime movers and railway traction engine is critical. Paddle wheel dampers are used for crankshafts and camshafts.
The Paddle Wheel Damper has four major components: A spider, an intermediate ring and the two outer rings. The spider forms the hub of the damper and mounts on the crankshaft. The gear profile of the spider fits into the intermediate ring gear profile. The spider vibrates in the gap formed between the two gear profiles, of the spider and the intermediate ring, thereby working on the high pressure oil contained in the damper. This results in damping of shaft vibrations.
The gears, made to close tolerance, ensure effective damping and are effective for the entire speed range.
High strength materials chosen for the different components ensure a long trouble-free working life.
The adoption of flow forming technology to manufacture pulleys is the result of regular reviews of globally evolving technology and the drive to bring the latest technology and value to our customers. The use of flow forming technology brings a competitive advantage in the design and manufacture of the torsional vibration damper. Flow formed pulleys can be applied practically anywhere there is a need for a poly groove or conventional groove pulley. The design saves weight and cost, which is a major objective for the modern designer. The process achieves very high productivity levels and is especially suited for high volume requirements. The process also shows a very high material recovery in comparison to conventional machined pulleys as the process is chip less.
The accuracies that can be achieved are comparable with a close tolerance machining process. Uninterrupted grain flow and an increase in mechanical strength is also achieved because of the process.
Advantages of a flexible marine coupling includes, reduction of torque fluctuations, damping of torsional vibrations, reduction of resonance symptoms, compensating of radial, axial & angular shaft displacements, isolation of vibration & noise transmission.Download PDF