The WH Type Oldham Coupling delivers parallel offset compensation, shock absorption, and cushioning in a single assembly. Nominal torque 16–5,000 N·m, speed up to 10,000 r/min, working temperature -20°C to +70°C. 10 sizes (WH1–WH10), Y-type and J1-type shaft ends available. Stocked and shipped globally by RP.
The WH Type Oldham Coupling is engineered for torque transmission applications where shaft misalignment compensation, vibration damping, and compact dimensions all matter. With a nominal torque range of 16 to 5,000 N·m and allowable speeds reaching 10,000 r/min on the smallest frame, the WH series fills the space between rigid couplings and fully elastomeric designs — delivering the constant-velocity characteristic of a sliding-disc Oldham with the added benefit of cushioning and shock attenuation from its intermediate element. Operating temperature: -20°C to +70°C.
An Oldham coupling is a three-piece mechanical power transmission device designed to connect two parallel shafts that share a common axis but are offset from one another. The assembly consists of two outer hubs — each bored and keyed to one of the rotating shafts — and a central intermediate disc (the slider) that engages both hubs via perpendicular tongue-and-slot interfaces on each face. As the assembly rotates, the intermediate disc slides within these slots to accommodate the lateral offset, transmitting torque with a constant 1:1 velocity ratio regardless of the misalignment present.
The engineering problem the Oldham design resolves is fundamental to rotating machinery: perfect shaft alignment is rarely achieved or maintained in practice. Motor mounting tolerances, thermal expansion, structural deflection under load, and cumulative assembly errors all introduce some degree of parallel offset between connected shafts. A rigid coupling transmits this offset as a bending moment directly into shaft bearings, seals, and couplings — accelerating wear and shortening service life. An Oldham coupling intercepts the offset kinematically at the floating disc, keeping the bearing force path clean.
The WH Type Oldham Coupling extends the classic Oldham concept by selecting an intermediate disc material that also provides vibration damping and cushioning. This makes the WH series distinctly different from purely rigid Oldham designs: it can attenuate shock loads, absorb minor torsional impulses, and reduce noise transmission through the drivetrain. The result is a coupling that performs well in servo-driven systems where start-stop cycling introduces repeated torque spikes, and in automation lines where adjacent machine vibration would otherwise propagate through a rigid coupling into sensitive instrumentation.
The three-piece kinematic mechanism works as follows. Each hub face carries a single raised rectangular tongue machined to close tolerances. The intermediate disc carries two perpendicular slots — one on each face — that receive these tongues as a sliding fit. When the input hub rotates, its tongue pushes the disc in one linear direction. The disc simultaneously slides in the perpendicular direction relative to the driven hub. The net output is pure rotation transmitted at a constant velocity ratio of exactly 1:1.
The WH Type achieves higher allowable speeds than many heavy-duty Oldham designs because its compact geometry keeps the disc mass and orbit radius small — the WH1 operates at up to 10,000 r/min. The intermediate disc material selected for the WH series is engineered to balance sliding wear resistance, shock attenuation, and dimensional stability under repeated thermal cycling across the rated temperature range of -20°C to +70°C.
For applications in servo positioning systems, encoders, and CNC spindle auxiliaries, the constant velocity ratio is particularly important. Any elastic element in the torque path introduces torsional windup — a phase lag between input position command and output shaft position. This appears as a tracking error in closed-loop control systems and limits achievable positioning accuracy. The WH Type's rigid torque path through the tongue-and-slot interface maintains a fixed angular relationship between input and output, preserving positioning fidelity.
All published performance parameters and dimensional data for the WH series are shown in the tables below. Use these for initial coupling selection; our engineering team can verify suitability based on your duty cycle, start-up torque profile, and installation envelope.
| Type | Nominal Torque Tn (N·m) | Allowable Speed [n] (r/min) | Bore Dia. d (mm) | Hub Length L (mm) | Dimensions (mm) | Weight (kg) | ||||
|---|---|---|---|---|---|---|---|---|---|---|
| Y-Type L | J1-Type L | D (mm) | D1 (mm) | B (mm) | C (mm) | |||||
| WH1 | 16 | 10000 | 10–14 | 25–32 | 22–27 | 40 | 30 | 52 | 17 | 0.6 |
| WH2 | 31.5 | 8200 | 12–18 | 32–42 | 27–30 | 50 | 32 | 56 | 22 | 1.5 |
| WH3 | 63 | 7000 | 18–22 | 42–52 | 30–38 | 70 | 40 | 60 | 22 | 1.8 |
| WH4 | 160 | 5700 | 20–28 | 52–62 | 38–44 | 80 | 50 | 64 | 22 | 2.5 |
| WH5 | 280 | 4700 | 25–32 | 62–82 | 44–60 | 100 | 70 | 75 | 27 | 5.8 |
| WH6 | 500 | 3800 | 30–45 | 82–112 | 60–84 | 120 | 80 | 90 | 37 | 9.5 |
| WH7 | 900 | 3200 | 40–55 | 112 | 84 | 150 | 100 | 120 | 42 | 25 |
| WH8 | 1800 | 2400 | 50–70 | 112–140 | 84–107 | 190 | 120 | 150 | 52 | 55 |
| WH9 | 3550 | 1800 | 65–85 | 142–172 | 107–132 | 250 | 150 | 180 | 62 | 85 |
| WH10 | 5000 | 1500 | 80–100 | 172–212 | 132–167 | 330 | 190 | 180 | 62 | 120 |
| Type | Torque Tn (N·m) | Max Speed (r/min) | Bore Range (mm) | Typical Application Tier |
|---|---|---|---|---|
| WH1 | 16 | 10,000 | 10–14 | High-speed servo / encoder |
| WH2 | 31.5 | 8,200 | 12–18 | Servo & automation |
| WH3 | 63 | 7,000 | 18–22 | CNC & packaging |
| WH4 | 160 | 5,700 | 20–28 | Light industrial drives |
| WH5 | 280 | 4,700 | 25–32 | Pump & conveyor auxiliary |
| WH6 | 500 | 3,800 | 30–45 | Medium industrial |
| WH7 | 900 | 3,200 | 40–55 | Medium-heavy drives |
| WH8 | 1,800 | 2,400 | 50–70 | Heavy process drives |
| WH9 | 3,550 | 1,800 | 65–85 | Heavy industrial |
| WH10 | 5,000 | 1,500 | 80–100 | Heavy process & mill drives |
Lightweight, electrically insulating, and naturally self-lubricating. Well suited to the higher-speed smaller WH frame sizes where mass must be minimised. Cost-effective for volume OEM applications in packaging, robotics, and light automation. Operating temperature range aligns well with the WH series rating of -20°C to +70°C.
Higher rigidity and superior dimensional stability compared to nylon. Better suited to larger WH frame sizes where higher torque loads are transmitted and wear resistance over extended maintenance intervals is a priority. Minimal moisture absorption maintains consistent tongue-slot clearance in humid environments such as food processing facilities and water treatment plants.
Standard hub material for the majority of WH Type applications. The strength-to-weight ratio of aluminium alloy keeps coupling inertia low — critical for the high-speed servo and positioning applications where the WH1 through WH4 sizes are most commonly deployed. Anodising and hard-coat options are available for improved surface hardness and corrosion resistance.
Specified for food processing, beverage, pharmaceutical, and marine drive applications where regular washdown with alkaline or acidic cleaning agents is standard practice. Grade 304 and 316 stainless steel options are available.
Need a heavier-duty coupling for higher torque or greater radial offset? Explore the full RP coupling range, including the SL Type Oldham series covering torque up to 63,000 N·m.
Use this as a starting point for technology selection; our team can provide application-specific guidance.
| Parameter | WH Oldham Coupling | Jaw Coupling | Bellows Coupling | Disc Coupling |
|---|---|---|---|---|
| Parallel Offset Compensation | Good (by sliding disc) | Limited (0.1–0.5 mm) | Low (0.1–0.3 mm) | Very Low (<0.1 mm) |
| Angular Offset Compensation | Low | Moderate (1°–2°) | Good (1°–3°) | Low (0.5°–1°) |
| Backlash | Near Zero | Low–Moderate | Near Zero | Near Zero |
| Shock Absorption | Yes — disc material | Yes — spider element | Minimal | Minimal |
| Electrical Insulation | Yes (polymer disc) | Yes (spider) | No | No |
| Suitable Speed Range | Up to 10,000 r/min | Up to 6,000 r/min | Up to 10,000+ r/min | Up to 10,000+ r/min |
| Constant Velocity Ratio | Yes — true 1:1 CV | Yes | Yes | Yes |
| Installation & Maintenance | Simple — disc slides out radially | Simple — spider accessible | Moderate | More complex |
| Relative Cost | Moderate | Low | High | High |
Procurement teams and maintenance engineers globally specify RP couplings for three consistent reasons: verified quality systems, flexible custom specification capability, and a team that responds clearly when a coupling question arises during a maintenance window.
WH Type Oldham Couplings are manufactured under an ISO 9001 certified quality management system. Products comply with RoHS directives. CE conformity documentation is available on request for export and compliance purposes. Material test certificates (MTCs) for steel and stainless steel hubs are available for safety-critical applications.
We support custom bore diameters, keyway profiles (parallel, Woodruff, DIN, and standard), modified hub materials, and surface treatments including hard anodising and electroless nickel plating. Alternative intermediate disc materials — including food-grade variants — are available to order. Minimum order quantity for custom work is 5 pieces. Lead time is typically 7–15 business days from drawing confirmation.
Standard in-stock orders ship within 2–3 business days. Standard products in original condition can be returned within 30 days. Custom-specification orders are subject to prior approval for return or exchange.
Have a specific application requirement? Our team is ready to assist with coupling selection, sizing confirmation, and custom specification. Contact a RP coupling specialist today.
Send us your shaft diameter, nominal torque, operating speed, and any misalignment data and our team will verify the correct WH size and material specification — typically within one business day.
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