Description
WH8 WH Type Oldham Coupling – 50–70mm Bore Shock-Absorbing Sliding-Block Flexible Drive Coupling
The WH8 WH Type Oldham coupling is a sliding-block flexible drive coupling designed for applications transmitting 1800 N·m at up to 2400 rpm where a certain degree of shaft relative offset compensation, shock absorption, and vibration damping capability are all simultaneously required. With a 190 mm outer diameter and bore range of 50–70 mm, it suits the full range of industrial shaft connections in this torque class — from compact instrument drives at the WH1 end of the series to large pump and processing equipment drives at the WH10 level. The coupling’s working temperature range of -20°C to +70°C covers standard industrial and outdoor service environments. At 1800 N·m for 50–70 mm shaft bores, the WH8 covers large industrial motor output shaft connections in the 75–250 kW power class. The coupling’s vibration damping properties are valued in marine thruster and large conveyor drive applications where transmitted vibration affects the surrounding structure.
The WH Type coupling is a three-component sliding-block Oldham design: two identical metal hubs, each mounted on one shaft, and a central polymer slider block that simultaneously engages the tongue-groove features on each hub face. Torque is transmitted through the sliding contact between the polymer block tongues and the metal hub grooves. Relative radial displacement between the two shafts is absorbed by translational sliding of the block within the hub grooves during rotation. The polymer block material provides inherent shock absorption by deflecting elastically under peak torque loads, attenuating transient torque spikes before they are transmitted to the connected shaft and its bearings. This shock absorption characteristic distinguishes the WH Type from rigid Oldham couplings and makes it particularly valuable in drive applications with variable or intermittent loading.
Y-type (standard length) and J-type (short hub) bore configurations are both available for the WH8, with bore length dimensions of 112–140 mm (Y-type) and 84–107 mm (J-type). The full WH series documentation and selection guidance is available on our product catalog page.
Technical Specifications
| Parameter | Value |
|---|---|
| Model | WH8 |
| Type | WH Type Oldham (Sliding-Block) Coupling |
| Bore Range (d) | 50–70 mm |
| Outer Diameter (D) | 190 mm |
| Inner Hub Diameter (D₁) | 120 mm |
| Slider Block Width (B) | 150 mm |
| Tongue Depth (C) | 52 mm |
| Y-Type Bore Length (L) | 112–140 mm |
| J-Type Bore Length (L) | 84–107 mm |
| Nominal Torque (Tn) | 1800 N·m |
| Maximum Speed [n] | 2400 rpm |
| Working Temperature | -20°C to +70°C |
| Mass | 55 kg |
Dimension Reference
Hub and Slider Block Assembly
The WH8’s intermediate slider block is the functional core of the coupling. Machined from engineering polymer to precise tongue and groove dimensions, the block simultaneously engages the drive faces on both hub ends. The tongue width and groove dimensions on the WH8 are sized to provide adequate compressive contact area for reliable 1800 N·m torque transmission while maintaining the sliding clearance needed for radial compensation movement during rotation. The tongue depth dimension C = 52 mm determines the shear plane geometry of the engagement and is a key parameter in the coupling’s shock absorption capacity.
Shock Absorption
The polymer slider block deflects elastically under peak torque loads, attenuating drive transients and protecting both motor and driven equipment bearings from shock loading. This is the primary functional differentiator of the WH Type over rigid Oldham couplings.
Shaft Offset Compensation
Radial shaft offset between the two connected shaft centrelines is absorbed by the sliding mechanism, preventing transmission of radial forces to motor or driven equipment bearings — reducing bearing overload and extending equipment service life.
Vibration Damping
The polymer block’s internal damping dissipates vibrational energy transmitted through the drive shaft, reducing vibration levels in both the motor and driven equipment — beneficial in applications where vibration affects product quality or equipment fatigue life.
Y and J Bore Options
Both standard-length Y-type and short-hub J-type bore configurations are available, accommodating applications with different axial space constraints between bearing supports.
Manufacturing
Typical Applications
- Large industrial pump and fan drive connections — 100 kW and above motor shaft couplings with maximum offset compensation
- Steel mill and mining equipment drives — high-vibration environments with sustained high-torque requirements
- Rolling mill auxiliary drive connections — continuous duty high-torque motor couplings
- Large processing plant pump connections — variable-speed drive compatible couplings with shock absorption
For application enquiries and volume supply, please visit our contact page.
Customer Reviews and Case Studies
★★★★★
United Kingdom — Marine Propulsion Equipment
The WH8 Oldham coupling is installed on auxiliary propulsion and manoeuvring thruster drive connections on our patrol vessels. The coupling compensates for hull flexure misalignment and absorbs the shock torque of thruster direction reversal.
— Marine Engineer, Plymouth
★★★★★
Brazil — Mining Conveyor Equipment
Used on large belt conveyor tail drum drive connections at our iron ore mine. The WH8 at 1,800 N·m handles the drive torque of our heavy-duty conveyors and accommodates the structural frame deflection under full-load belt tension.
— Conveyor Engineer, Belo Horizonte
★★★★☆
Vietnam — Textile Mill
Installed on large loom main drive connections. The WH8 couples the motor to the loom main shaft reliably and its shock absorption smooths the variable torque loading of the weaving cycle, reducing fatigue on the drive components.
— Maintenance Manager, Ho Chi Minh City
Frequently Asked Questions
Does the WH Type coupling require lubrication?
Standard polymer slider blocks are self-lubricating — no external lubricant is required on the tongue-groove contact surfaces under normal operating conditions. For metal slider versions at elevated load, a small amount of molybdenum disulfide or equivalent dry film lubricant applied to the tongue-groove contact surfaces at installation can extend service life.
What is the angular misalignment tolerance for WH Type couplings?
The WH Type coupling accommodates a certain degree of angular misalignment between the connected shaft centrelines. The exact angular compensation value varies by model and should be confirmed with the product dimension documentation. For precision shaft connections, both angular and radial alignment should be within the specified limits to maximise slider block service life.
Is the WH Type coupling suitable for variable-speed drive applications?
Yes. The WH Type coupling is compatible with variable-speed drive (VFD/inverter) motor applications. The shock absorption properties of the slider block are particularly beneficial in VFD applications where rapid acceleration and deceleration cycles generate high drive torque transients. The coupling attenuates these transients before they reach the driven equipment.
Can WH Type couplings be supplied with non-standard bore sizes?
Yes, within the bore range specified for each model. If a non-standard bore diameter within the model’s bore range is required, specify the exact bore diameter and tolerance when placing your order. Bore sizes outside the model’s standard range require a custom design — contact Ever Power to discuss.
How does the WH Type coupling compare to a flexible jaw coupling?
Both the WH Type Oldham and jaw couplings provide shock absorption and misalignment compensation. The WH Type’s Oldham mechanism transmits torque at a constant velocity ratio regardless of offset angle — jaw couplings with spider elements introduce slight velocity variation under misalignment. The WH Type’s replaceable slider block also allows maintenance without hub removal, whereas jaw spider replacement typically requires some hub axial movement.
Enquire About the WH8 WH Type Oldham Coupling
Ever Power manufactures the WH8 and the complete WH Type coupling range — 10 models from WH1 to WH10 covering 16 N·m to 5,000 N·m — direct from our factory. Specify your bore diameter, bore type (Y or J), operating torque, and speed for a prompt technical and commercial response.
