7 Reasons to Consider Oldham Couplings
1. Zero-Backlash OperationOldham couplings are a three-piece assembly comprised of two lightweight aluminum or corrosion resistant stainless steel hubs and a center disk. The tenons on the hubs mate to the slots in the disk with a slight press fit, allowing the coupling to operate with zero-backlash. Oldham couplings are commonly used in servo-driven systems that require precise motion control and a low inertia, balanced design. |
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2. Application FlexibilityHubs with the same outside diameter can be clamp or set screw with bores that are keyed or keyless and inch or metric, allowing for a high variety of pairing options. Disks are available in acetal for zero-backlash and high torsional stiffness, nylon for dampening, and PEEK for high temperature. |
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3. High Parallel Misalignment CapabilitiesOldham couplings are capable of accommodating parallel misalignment up to 10% of their OD with low bearing loads. This can be done because the only resistance is the friction of the disk sliding over the hub tenons. This parallel misalignment is significantly higher than what other servo couplings are capable of and allows oldham couplings to be used in applications with otherwise prohibitive shaft misalignment. |
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4. Blind AssemblyOldham couplings can be used in systems where shaft access is limited due to their three-piece design. This saves a significant amount of time during repair or installation as the entire system assembly does not need to be taken apart. Oldham disks are easy to remove without the use of tools. |
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5. Electrical IsolationNo metal to metal contact allows for electrical isolation capabilities protecting delicate instruments such as encoders from electrical currents that may cause inaccurate data readings or damage. This is invaluable in many of the applications in which oldham couplings excel. Designers should test the coupling during the prototype stage to ensure they have a proper PM schedule. When the disk fails there is risk of an arc between the hub tenons if the voltage is high enough. |
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6. Fail Safe DesignIn a torque overload situation the disk will fail, immediately stopping power transmission. Some systems are likely to suffer damage from continued, compromised operation. Broken oldham disks are inexpensive, easy to replace, and their ability to function as a mechanical fuse is an excellent alternative to causing more expensive system components premature wear or failure. |
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7. Low Replacement CostWhen an oldham coupling fails the disk breaks and is generally the only item that needs replacement. Doing so is inexpensive compared to couplings with single piece designs. Additionally, installing a replacement disk can be done quickly and easily, reducing system downtime. |
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