Coupling Resists Leakage In Solar Panel Capacitor
August 26, 2010 by CouplingTips
Filed under Flexible, Linear
Huco Dynatork has supplied its Multi-Beam coupler for use in a solar panel high-voltage capacitor manufactured by a Japanese consumer electronics company.
The flexible misalignment coupling is used to connect the drive from the gearbox to a lead screw and had to be able to resist any current leakage.
It is ideal for a variety of precision motion applications that require torsional stiffness and zero backlash, but had to be manufactured from a non-standard material to prevent current leakage across the drive.
To achieve the required high resistance, Huco Dynatork selected Victrex Peek.
This polymer offers high mechanical strength in high temperatures, and good chemical resistance and electrical insulation properties.
Shoulder Couplings Ideal For Abrasive Surfaces
July 13, 2010 by CouplingTips
Filed under Beam, Linear
Victaulic now offers a new line of products for joining standard shouldered steel pipe. The product line features the Style SC77, a flexible coupling featuring Victaulic patented installation-ready technology, and a variety of prefabricated shouldered fittings designed to make pipe joining even more efficient. The product line is ideal for abrasive services, particularly in the mining industry, where maintaining full pipe-wall thickness is important.
Six factors to remember about couplings in a motion system
Physical values such as torque, torsional rigidity, spring stiffness, moment of inertia, imbalance, and zero-backlash play a major role in coupling design. Here are a few facts to keep in mind when you design your motion system.
Torque (Nm): is the product of an acting force and the effective length of the acting force’s lever arm.
T = Fxr
T = Torque (Nm)
F = Force (N)
r = Lever arm (m)
With a force of 100 N and a 1 m long lever arm, you can generate a torque of 100 Nm. Or, you can generate a torque of 100 Nm with a force of 1000 N and a 0.1 m long lever arm. For couplings, a specific amount of torque can be achieved with a large outer diameter of the coupling and a correspondingly low acting force or with a small outer diameter and a correspondingly high acting force.
Torsional rigidity (Nm/rad): refers to the rigidity of a coupling when it is subjected to a torsional load. If the torque exceeds the maximum torsional value of the coupling, the coupling will no longer be strong enough to transmit the acting rotational force. Ex: If a coupling with a torsional rigidity of 10 000 Nm/rad is subjected to 10 Nm, the connection element will twist by 1/1000 rad. That is equal to an angle of twist of about 0.057 degrees (1 rad = 57°17’44.8”). For a torsionally rigid or vibration damping coupling, this angle of twist may still be within the admissible range. In practice, torsionally rigid couplings normally have a maximum angle of twist of less than 0.05 degrees and vibration damping couplings have a maximum angle of twist of less than 5 degrees.
Spring Stiffness (N/mm): is the counterforce exerted by the coupling in case of differentiated position of the axes in an axial, radial, and lateral direction. Ex: If the axial spring stiffness of a coupling is 30 N/mm, the coupling will exert a force of 30 N in the case of an axial displacement of 1 mm. These forces are important in a design with couplings, particularly when selecting bearings or other drive system components.
Moment of inertia: is the moment resistance when the rotational speed is changed. Normally, the lower the total weight and the smaller the outer diameter of the coupling body, the lower the moment of inertia. The reverse is also true, the higher the weight and larger the outer diameter, the higher the moment of inertia. This feature is important in highly dynamic applications because the drive has to generate sufficient torque to overcome a body’s moment of inertia to accelerate and decelerate.
Imbalance: in a drive system, imbalance should be as low as possible for smooth operation. Caused by asymmetries in the drive system where mass is distributed unevenly, it affects centrifugal forces on the entire drive system. It can be rectified by “balancing bores,” which are normally drilled directly into the location of the disproportionally high concentration of mass.
Zero backlash: is a lack of empty space or “play” when the rotational speed, direction of rotation, or torque changes. It does not mean that there is no angle of twist. Backlash is an important factor in predicting bearing life.
Information courtesy of R+W America
EZV Series Adjustable Line Shafts from R+W America
February 18, 2010 by CouplingTips
Filed under Beam, Bellows, Linear
A convenient location for manual phase adjustment along a mechanical drive system is now available in the EZV series adjustable line shafts. Making use of a high strength intermediate collar between two telescoping sections of precision tubing, the EZV naturally places the location for phase adjustment in an easily accessible, open space. Due to the relatively large outside diameter of the drive tubing, the EZV also provides for a more secure clamping connection than would exist when clamping over standard diameter motor and gearbox shafts.
Length adjustability also results from this design, making the EZV reusable in different machine layouts, and easier to install, especially with certain alternate hub designs, like EK7 expanding mandrels and EK6 high strength conical clamp ends. For any size the EZV can also be made with ZAE torsionally rigid bellows couplings, or with integral ES2 mechanical torque limiters.
R+W America
www.rw-america.com
