Coupling Resists Leakage In Solar Panel Capacitor

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.

Explosion proof couplings

Flexible couplings are a critical component for applications involving potentially explosive materials found in automotive paint and cleaning stations, chemical plants, and powder mixing areas.  A lack of radially flexible elements in shaft linkage can result in high radial loads on shaft bearings, eventually leading to heat generation and bearing failure, making flexible shaft couplings essential to machine drive design in these cases.  Even more critical is that the potential for sparks must be eliminated.  For use in explosive environments R+W has developed a full range of ATEX certified “explosion proof” couplings in accordance with the European directives, ATEX 95 and ATEX 137.

These special couplings are precision machined with a thermally and chemically stable, wear resistant, polyurethane insert press fit between the two for zero backlash.  A smooth fit between the insert and the hubs helps the insert to compensate for lateral, angular and axial shaft misalignment.  The insert is impregnated with graphite, giving it electrically conductive properties, eliminating the potential for any charges arcing from one hub to the other.  Official serialized markings including the part number are required by the directive and are clearly visible on each unit.

These precision couplings are available in a variety of mounting configurations, and can include torque overload protection.  There are nine total sizes ranging from torque ratings of 2 – 2150 Nm (17 to 19,000 in-lbs).  Both English and metric bore diameters are available in a range from 3 – 80 mm (1/8 to 3.125 in.) with or without keyways.

R+W America
www.rw-america.com

Candy Coup-link Line of Zero Backlash Flexible Shaft Couplings

Coup-Link is a full line of zero backlash flexible shaft couplings including Beam, Bellows, Jaw, Disc and Oldham.  All are available in a variety of mounting options including set screw, keyway, clamp, conical and shrink disc configurations.

Beam, Disc, Jaw, Bellow, Encoder and Oldham couplings

Motors, reducers, encoders, shafts and other rigid elements often fail prematurely. Many times this is from misalignment, which often leads to bearing, shaft or seal failure. Zero backlash, flexible shaft couplings  accommodate parallel and angular misalignment and shaft endplay.

Properly selecting a Candy Coup-Link provides the flexibility to handle many types of misalignment and may offset problems such as minor design errors or improper assembly.

Candy Mfg. Co.
www.candycontrols.com

GERWAH® Product Line

The GERWAH® line of products consists of magnetic couplings, metal bellows couplings, servo-insert couplings, line shafts, RING-flex® couplings and safety couplings. These couplings are available in a range of sizes and torque capacities to 3,800 lb-ft. The low mass of the lightweight construction helps increase machine performance and reduce energy costs.

Ringfeder Power Transmission USA Corporation markets a range of power transmission components and keyless shaft/hub technology.  Other power transmission products include shock absorbing devices, flexible elastomeric couplings, flexible disc couplings and torque limiters along with other specialty and custom made products.

RINGFEDER

www.ringfeder.com

Elastomer couplings with higher torque handling capacity

The growing popularity of curved jaw (elastomer) style couplings for precision applications has driven the need for couplings that handle more than the traditional torque capacity of 2,150 Nm up to a maximum torque of 25,000 Nm.

Available with split clamping collars or keyway and set screw connections, the three new body sizes allow for backlash free, vibration damping power transmission, paired with strong torque density. Dual flexture and jack shaft versions are also available for spanning longer distances and compensating for larger misalignments. Unlike the pre-existing range of R+W elastomer couplings, which use a single spider element between the new hubs, the new larger sizes will use individual vibration damping compensation elements to fit between each mating set of coupling teeth. These couplings are available in English and metric bore diameters up to 170 mm.
R+W America
www.rw-america.com

Low Inertia Aluminum Couplings Reduce Cycle Time

The aluminum CD® model is a low inertia, lightweight coupling with high torsional stiffness for servo motor applications. It is available in single and double flex versions.

“We surveyed design engineers to find out what was the most desirable feature when specifying couplings for servo motor applications,” reports Robert Mainz, Zero-Max sales manager. “Low inertia was the most important.” These engineers said they continually look for ways to reduce cycle time and improve system productivity. A lightweight yet high strength coupling design will let you increase the speed of the actuator. Lightweight couplings will also have an effect on the energy consumption in their designs.

The working part of the CD® coupling is made of a special composite material. The composite disc design withstands the stresses of a servomotor’s high acceleration rates and high torque capacity better than other coupling designs. This results in lower energy requirements, and longer life of the motor and other operating components while ensuring uninterrupted system operation.

Zero-Max CD couplings are available in single and double flex models with or without keyways. The double-flex version is for precision applications requiring misalignment capacity greater than the single flex design. The single flex models have a torque capacity range from 40 Nm to 1436 Nm and beyond with speed ratings from 4400 RPM to 17,000 RPM.

Zero-Max
www.zero-max.com

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

Rw-america.com

Schmidt 5D Couplings Handle Axial, Angular And Parallel Shaft Misalignments

Schmidt 5D Couplings suit applications requiring large axial, angular and parallel shaft misalignments. This “all-in-one” coupling design will handle all shaft displacements providing low backlash for precision high torque applications such as roll forming and similar heavy duty fabricating equipment.

Designed to fill an important need in the Zero-Max family of torque-rigid couplings, these couplings allow for easy adjustment to any possible misaligned shaft position without imposing heavy side loads on shafts, bearings or other machine equipment. The coupling can accommodate up to 5 degrees of angular misalignment and as high as 1.5 in. parallel misalignment while maintaining undisturbed power transmission at constant angular velocity. Acting forces within the coupling can be precisely calculated, assuring reliable, trouble-free system operation. This unique design will tolerate high shock and reversing loads with minimal or no maintenance required.

Additional features include: space-saving design and easy installation — couplings can be mounted to shaft hubs or directly to existing machine flanges (no need to reposition either shaft being coupled). Available in standard and inverted hub configurations in bore sizes from 1.500 in. to 6.375 in. or 38 mm to 160 mm. Custom designs can take this coupling design beyond the catalog specifications. The ten different model sizes handle speeds up to 1000 RPM and torque from 2800 to 500,000 in-lb. Special design modifications are available.

“The 5D coupling has very robust design features for use in applications such as roll drive systems used in converting machinery. The unique and flexible design allows for a range of movement to improve the quality of the end product.” reports Robert Mainz, Zero-Max sales manager. “They do a very good job of handling shaft misalignments and protecting drive train components in these high performance systems.”

Zero-Max
www.zero-max.com

For safety, electronics may not be the best choice

The trend of replacing mechanical systems with electrical systems continues. Even developers of hydraulic and pneumatic systems are following it. But, as is becoming evident through the latest unintended acceleration issues, electronic components can have a few drawbacks that should not be overlooked in a design.

When in comes to designing a system for safety, specifically when considering whether to choose a mechanical component such as a coupling, or to go electronic, remember this: Electronic safety components have two major disadvantages compared to mechanical safety components.

1. Reaction time. Assume a machine crashes and causes an overload. According to engineers at R+W America, a signal from the monitoring circuit does not reach the motor controller until 5 to 7 ms following a sharp increase in torque. During this period of latency, the controller attempts to further increase torque to reach the setpoint value. Most likely, another 10 ms will pass before the motor is shut off. Depending on the drive train’s moments of inertia, more time can pass before the electronics brings the whole system to a stop.
2. Multiple potential failure sources. Electronic monitoring systems need multiple sensors for data. Between the monitoring system and all of its sensors and other components, you have a system with multiple possible points of failure.

A mechanical safety coupling, on the other hand, completely disconnects the drive from the load within 3 to 5 ms; 1/3 of the time needed by an electronic cut-off. Noted engineers at R+W America, “electronic machine monitoring is not suitable for high speeds due to the large centrifugal mass of the rotating parts.”

Also with a mechanical safety coupling, you have one component per axis, reducing the number of possible points of failure.

Safety couplings must demonstrate two clear behaviors:

1. Upon overload, separation of drive train and load should occur within a few milliseconds.
2. After the coupling has disengaged, residual friction should not be excessive so as not to damage coupled components that continue to be driven due to mass moments of inertia.

According to R+W, safety couplings can be subdivided into five classes:

1. Rigid safety couplings used in indirect drive applications.

2. Torsionally rigid safety couplings for use between two shafts or flanges. These couplings resist twisting and can be subdivided into two groups.

A. Single-piece torsionally rigid safety couplings.

B. Press-fit couplings.

3. Vibration-damping safety couplings are fitted with an elastomer insert that damps incurred drive vibration.

4. Economy safety couplings suit applications requiring simple overload protection and functions as a variation of the ball-detent principle.

5. Torque-limiting line shafts, which span long distances between shafts.

(Some material, courtesy of R+W America.)

Machined Spring Features HELI-CAL Flexure

SANTA MARIA, CA—The HELI-CAL® Flexure is a flexible helix (curved beam) machined into a unique configuration that incorporates special design requirements, performance features and/or characteristics. The material is basically unlimited.

When used as a spring, the multi-functional flexure provides desired and predictable elastic performance in compression, extension, torsion, lateral bending and lateral translation modes.

One huge advantage of this technology—it enables customer specified end-attachments, such as tangs, clamps, flanges or threaded ends to be integrated into a single multi-functional component.

Helical Products Company, Inc.
www.Heli-Cal.com

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