Motors

Ruland rigid couplings have the greatest torque capability and torsional rigidity of any Ruland coupling. This makes them ideal for motor applications with high torque and accuracy requirements. Rigid couplings have no flexible element and can not accommodate any type of shaft misalignment. Ruland precision hones straight bore rigid coupling to remove any residual distortions from the manufacturing process ensuring bores are collinear and will not introduce any misalignment or excess vibration into the system.

Ruland rigid couplings come with screws treated with proprietary Nypatch® anti-vibration coating. This coating prevents galling and allows for even seating of the screw and repeated screw installations. No additional screw treatment is needed saving a significant amount of time in assembly. Rigid couplings are available in set screw and one- and two-piece clamping styles and manufactured in 1215 lead-free steel with a black oxide finish for the highest holding power, lightweight 2024 aluminum for low inertia, and 303 stainless steel for corrosion resistance. Bore sizes are available from 1/8” to 2” and 3mm to 50mm.

Beam couplings from Ruland are manufactured with multiple spiral (helical) cuts allowing for zero-backlash and greater torque, torsional stiffness, and misalignment capabilities when compared to standard single beam couplings. The 4-beam style (P- and MW-Series) have two sets of two beams allowing for greater flexibility and more compact lengths than 6-beam couplings, making them an ideal encoder coupling. The 6-beam style (F-series) has two sets of three beams for increased torque and torsional stiffness capabilities when compared to 4-beam style. They are best suited for light duty power transmission applications such as coupling a motor and lead screw.

Most motor designers start with aluminum beam couplings for their cost effectiveness and low inertia. Stainless steel beam couplings are designed for motor applications with higher torque than an aluminum coupling can accommodate, but designers must be careful when using one, as they have significantly greater inertia than aluminum types. Ruland manufactures beam couplings with a balanced design for smooth operation up to 6,000 RPM. They are available in clamp and set screw styles with bores in sizes from 3/32” to ¾” and 3mm to 20mm.

Bellows couplings are zero-backlash and constructed of two anodized aluminum hubs and a stainless steel bellows that serves as the flexible element. This design results in a low inertia zero-backlash coupling that is a good choice for motors coupled to ball screw driven actuators in precision applications. The thin walls of the bellows allow the coupling to flex under misalignment conditions and remain rigid under torsional loads. Bellows couplings have the highest size-for-size torque and torsional stiffness of all Ruland flexible couplings and are preferred in applications where the highest level of accuracy and responsiveness is required.

Ruland bellows coupling have a balanced design for reduced vibration at speeds up to 10,000 RPM. Bore sizes are available from 1/8” to 1” and 3mm to 25mm and hubs are manufactured in clamp and set screw styles with and without keyways.

Ruland zero-backlash disc couplings have high torque and torsional stiffness capabilities and a balanced design. They are manufactured in single and double disc styles. Single disc couplings are comprised of anodized aluminum hubs and stainless steel disc springs. This style is good for space constrained applications, but cannot support parallel misalignment. Double disc couplings are comprised of anodized aluminum hubs, an anodized aluminum or electrically isolating acetal spacer, and stainless steel disc springs. The double disc style can accommodate greater amounts of all types of misalignment, including parallel misalignment.

As lightweight, high-performance couplings, disc couplings have comparable performance characteristics to bellows couplings. They have slightly less torsional stiffness and torque capacity than bellows couplings, but offer better misalignment accommodation. They are well-suited for servo motors that will be used for precise positioning applications such as those found in semiconductor, solar, and robotics. Ruland disc couplings are manufactured in clamp or set screw style, with or without keyways, in bores sizes from 1/8” to 1-1/4” and 3mm to 32mm.

Ruland zero-backlash jaw couplings have high dampening capabilities and can accommodate all forms of misalignment, making them well suited for applications with high acceleration and deceleration curves that couple a motor with a screw driven actuator or gearbox. Ruland jaw couplings are made up of two aluminum hubs and an elastomeric insert called the spider. They give motor manufacturers and integrators a standard coupling with a high level of customization. Hubs can be easily interchanged between clamp and set screw, with or without keyway and spiders have three durometers to choose from. This flexibility allows designers to specify an outer diameter with a variety of inch and metric bore sizes will match joined components such as lead screws, ball screws, and gearboxes.

Ruland hubs are manufactured with a proprietary curved jaw profile that ensures zero-backlash operation for fine positioning. Designers can select from three different spider durometers, enabling them to balance dampening, torque, and torsional rigidity based on the needs of their application. The spider serves as an inexpensive wear element that restores the coupling’s performance characteristics when replaced, saving maintenance costs when compared to couplings that must be entirely replaced. In the event of failure, the hub tenons will interlock for continued power transmission to allow the system to be shut down safely.

Zero-backlash jaw couplings are manufactured by Ruland with bores sizes ranging 1/8” to 1-1/4” and 3mm to 32mm.

Ruland oldham couplings are comprised of two anodized aluminum hubs and a center disk. Oldham couplings offer the greatest parallel misalignment accommodation of all Ruland servo couplings as well as low inertia and electrical isolation, making them a fit for a variety of motor systems. They are manufactured with a proprietary machining process for smooth interaction between the hub tenons and disk allowing for the longest service life in the industry. Ruland oldham couplings have a balanced design for reduced vibration at speeds up to 4,500 RPM.

Oldham couplings are highly versatile because of the variety of hub and insert materials available. Acetal, Nylon, and PEEK disks offer a balance between torque, torsional rigidity, and environmental compliance. Aluminum oldham coupling hubs are lightweight, cost effective, and offer low bearing loads. Stainless steel oldham couplings can be used in corrosive, cleanroom, and vacuum environments when paired with a PEEK disk. This combination is useful for motors in food processing applications. The multitude of standard options makes oldham couplings a good starting choice for motor manufacturers or integrators that package systems with lead screws, ball screws, or gearboxes. The same base oldham coupling hub can be specified with the motor while the disk and second hub change depending on the joined component.

Ruland manufactures oldham coupling in our Marlborough, MA factory with bore sizes ranging from 1/8” to 1-1/8” and 3mm to 30mm. They are zero-backlash when used with an acetal or PEEK disk.

Controlflex couplings are a multi-piece assembly made up of two aluminum hubs joined together by one or two center inserts called frogs. Controlflex is a good starting point for light duty applications such as those with stepper motors or as encoder coupling for a servo motor becausy they are electrically isolating, capable of speeds up to 25,000 RPM, and designed to accommodate all forms of misalignment. Controlflex couplings with a single frog have higher misalignment capabilities and fit in space constrained applications. The double insert style offers higher torque and torsional stiffness. The frogs are designed to remain rigid while flexing under misalignment conditions.

The multi-piece design offers a great amount of flexibility when specifying a controlflex coupling. Designers can use the same coupling outer diameter on each design and fit the rest of coupling based on the performance requirements of the system. Controlflex has a wide range of shaft size accommodation within a given outer diameter, typically a 3:1 ratio of large bore to small bore. This is critical in servo motors where an encoder is generally used to maintain position. Often there is a large step in shaft size between the desired encoder and the motor. Other coupling styles would require special designs to accommodate these differences, whereas controlflex can accommodate this step in shaft sizes with standard off the shelf hubs.

Controlflex couplings are manufactured by Schmidt Kupplung in Germany and stocked and bored to size by Ruland in our Marlborough, MA factory. They are available in bore sizes from 1/8” to 1-1/2” and 3mm to 40mm.

Slit couplings are manufactured from a single piece of 7075 aluminum alloy and their balanced design provides smooth transmission of motion, low bearing loads, high torsional stiffness, and long life. They support speeds up to 70,000 RPM and accommodate all forms of misalignment, making them a good choice for high precision systems such as those found in medical, semiconductor, and robotics. A proprietary slit pattern with radiused edges reduces stresses that build up during misalignment conditions and torque loads allowing for reduced wear and stress on the coupling.

Slit couplings have a high-performance design that balances torque, misalignment, and torsional stiffness capabilities. Their torque capacity is comparable to a single disc coupling while their torsional stiffness is similar to a stainless steel beam coupling. Slit couplings offer misalignment accommodation most similar to an aluminum beam coupling. As a result, slit couplings are well balanced and ideal for demanding motor applications with high misalignment. Ruland offers slit couplings in RL- and RS-series. The longer length RL-series couplings allows for greater parallel misalignment capabilities and increased torsional stiffness. In comparison, RS-series couplings are shorter and designed to fit in compact spaces and offer parallel misalignment capabilities, which is an advantage over comparable single disc couplings.

Slit couplings are available in clamp screw and set screw designs with inch, metric, and inch to metric bore sizes ranging from 1/8” to 3/8” and 1.5mm to 12mm. They are manufactured by Reliance Precision Ltd. in their Cork, Ireland factory. Ruland stocks and bores to size slit couplings in our Marlborough, MA factory.

Ruland shaft collars offer high holding power and precise face to bore perpendicularity making them ideal for the precise location of motor components, such as bearings. They can also be used for spacing, stopping, guiding, and mounting depending on the design of the motor. Ruland clamp type shaft collars are ideal for motors as they do not the mar the shaft, are infinitely adjustable, and have high holding power. Clamp type shaft collars wrap evenly around the shaft allowing for consistent clamping forces and a more precise fit when compared to set screw collars. Ruland offers one- and two-piece shaft collars in a variety of styles to match the varied needs of motor manufacturers. Two-piece shaft collars are mated throughout the manufacturing process for proper fit, alignment, and to maintain high holding power. Two-piece shaft collars have standard options with a balanced design which is suitable for high speed motors where the collar will be used on a rotating shaft.

Ruland manufactures shaft collars for motors from select North American bar stock in 1215 lead-free steel with a black oxide finish for high holding power, 303 & 316 stainless steel for corrosion resistance, and lightweight 2024 aluminum for low inertia. They are available in bore sizes from 1/8” to 6” and 3mm to 150mm.