Where should I use a Single-Flex (SC) versus a Double-Flex (SD) ServoClass Coupling?
Most applications will use the Double-Flex (SC) series of the ServoClass Coupling due to its misalignment capacity.The typical application for this is a 4-bearing system, as illustrated below:
With the 4 bearing systems, the shafts are fully supported and generally have some inevitable amount of misalignment and/or develop misalignment over time. The Double-Flex design readily accommodates any combination of parallel, angular, and axial misalignments and keeps reaction loads low on the connected components.
The Single-Flex (SD) series of the ServoClass Coupling is suited for use where support is needed for one shaft. The typical application for this is a 3 bearing “semi-floating shaft” application, as illustrated below:
The Single-Flex does not allow for parallel misalignment; however, it may also be used where a shorter length is required in an application with a very well piloted connection to eliminate parallel misalignment. Another use of the Single-Flex is to use two of them at either end of a customer-supplied shaft to make a Floating Shaft Coupling to accommodate a larger DBSE (distance between shaft ends).
Does Zero-Max provide a Floating Shaft version of the ServoClass Coupling?
No. Although a Floating Shaft is not available from the factory, many of our customers build their own Floating Shaft Coupling simply by using (2) Single Disc (SD) series couplings – one attached at each end to a customer-supplied intermediate shaft. This assembly arrangement offers a Floating Shaft Coupling to accommodate a larger DBSE (distance between shaft ends).
What is the maximum operating torque for the ServoClass Coupling?
The operating torque listed for the ServoClass Coupling is the maximum allowable torque for the coupling. Any peak torques or torque spikes anticipated in the application should be considered when sizing to the operating torque listed.
What is the minimum shaft engagement on a ServoClass Coupling hub?
Ideally, the shaft will engage the entire length of the hub (dimension “LB” in catalog). The shaft can also extend past the hub end into the disc-pack area as long as it does not come in contact with the disc-pack (check disc diameter dimension “K” in catalog) or the mating shaft or hub. If the shaft cannot engage the full length of the hub, it must still engage the entire flexing area of the hub for full torque transmission. This distance is approximately 2/3 - 3/4 of the overall hub length, depending on the size of the coupling. Please contact the factory if you have any questions.
Can I get a keyway on the hub bore?
Yes. Although the ServoClass Coupling is a keyless coupling in its standard form, keyways may be added per customer request at a nominal cost adder. Non-standard keyway sizes can also be accommodated in most cases.
Can I get custom bores or keyways?
Yes. Any inch bore sizes that fall on 1/16” increments and metric bore sizes that fall on a whole millimeter increments are standard for ServoClass Couplings. Zero-Max also offers custom bore sizes as well as non-standard keyways and custom tolerance bores and keyways to meet specific dimensional requirements.
Can I mount a non-keyed bore hub on a shaft with a keyway or flat?
Yes. The ServoClass Coupling hub can be mounted on a shaft with an empty keyway or a flat. The transmittable torque may be slightly reduced (due to the loss of the keyway/ flatted surface area for the clamp connection), but this is typically not a concern unless small bore sizes are used. Please contact the factory if you have any questions.
For optimal clamping force, we do recommend the keyway or flat is on the opposite side of the hub from the clamp screw. See diagram below for further details.
What if I have a tapered shaft in my application?
We offer tapered adaptors for some of the ServoClass Coupling sizes. The clamp-style hub itself does not allow for clamping onto the taper, however the tapered bore adaptor fits securely in the standard clamping hub bore and has an internal taper to secure it to the tapered shaft. The tapered adaptors have a 1:10 internal taper to match Fanuc servomotor shafts and other shafts having a 1:10 taper. The available tapered adaptor sizes are for an 11mm, 14mm, or 16mm major diameter of the taper.
Can I replace disc elements in the field?
No. Replacement discs are not available since the discs are not field-replaceable. Zero-Max uses purpose-built assembly fixtures at our factory to assemble ServoClass couplings with the concentricity required for optimal performance and life of the Coupling.
Can Zero-Max dynamic balance my ServoClass Coupling?
Yes. We can add dynamic balancing to the ServoClass Couplings as needed for applications. Typically, higher speed applications or equipment that is sensitive to vibrations (i.e. test equipment) may benefit from being dynamically balanced. Zero-Max has the technology required to do most coupling balancing jobs in-house, allowing us to offer an economical option with a faster turnaround.
Can I choose Style "A", "B", or "C" hub combination for my ServoClass Coupling?
No. The hub style combination used is based on the size of the coupling and the bore sizes required. Some ServoClass sizes have a reduced diameter hub for smaller bores that provides a higher clamping force to achieve optimal performance. Not all ServoClass Coupling sizes have a reduced diameter hub. The ServoClass Coupling sizes that have the reduced diameter hub are listed in the catalog, along with the range of bores that use this hub. Bore sizes larger than the maximum bore of the reduced diameter hub will utilize the standard diameter hub.
- Style "A" has (2) reduced diameter hubs
- Style "B" has (1) reduced diameter hub & (1) standard diameter hub
- Style "C" has (2) standard diameter hubs
Why choose a ServoClass Coupling versus a CD Coupling, or vice versa?
In most cases, the size of coupling needed for the application will determine where a ServoClass Coupling is used versus a CD Coupling. In general, the size range of the ServoClass Couplings handle the smaller applications in terms of torque, load, and shaft sizes, while the size range of the CD Coupling will handle larger applications. There are several coupling sizes that overlap between the ServoClass and CD Couplings. In those cases, which series is a better fit will depend on the application and requirements such as misalignment, torque, torsional stiffness, vibration, shock, delivery, cost, and more. Contact the factory to discuss your specific requirements.