Description
SL90 SL Type Oldham Coupling – 20–30mm Bore 90mm OD Radial Misalignment Compensating Drive Shaft Coupling
The SL90 SL Type Oldham coupling is a three-component sliding-block coupling designed for connecting two coaxial drive shaft lines where significant radial displacement between shaft centrelines must be accommodated without transmitting radial load to the connected equipment bearings. With a nominal torque rating of 250 N·m at 250 rpm maximum speed, 90 mm outer diameter, and a bore range of 20–30 mm, the SL90 serves drive connections in the full range of industrial machinery — from medium-duty pump and fan drives to large-scale industrial processing equipment. The radial displacement compensation of 0.7 mm, angular compensation of 0.5°, and axial accommodation of 1.4 mm make the SL Type one of the most flexible misalignment-compensating couplings available at this torque level.
The SL Type coupling operates through a three-piece sliding-block mechanism: two identical cast iron flanged hubs, each mounted on one shaft, and a central polymer (or metal) slider block that engages with both hubs simultaneously through tongue-and-groove interfaces positioned at 90° to each other. Torque is transmitted from the driving hub through the tongue-groove contact to the slider block, and from the slider block to the driven hub through the second pair of tongue-groove faces. Radial misalignment between the shaft centrelines is absorbed by sliding movement of the block within the hub grooves — the block translates in the plane perpendicular to the shaft axis as the coupling rotates, compensating for the offset continuously during operation. This mechanism produces a uniform angular velocity transmission — unlike some other misalignment-compensating coupling types that introduce cyclic velocity variation.
The slider block is a replaceable wear element. At planned maintenance intervals, the block can be inspected for wear and replaced without removing either hub from its shaft, minimising maintenance downtime. Full series documentation and application guidance are available on our product catalog page.
Technical Specifications
| Parameter | Value |
|---|---|
| Model | SL90 |
| Type | SL Type Oldham (Sliding-Block) Coupling |
| Bore Range (d) | 20–30 mm |
| Outer Diameter (D) | 90 mm |
| Inner Diameter (D₁) | 45 mm |
| Overall Length (L) | 52 mm |
| Hub Width (H) | 14 mm |
| Slider Width (S) | 0.5 mm |
| Nominal Torque (Tn) | 250 N·m |
| Maximum Speed [n] | 250 rpm |
| Radial Compensation (Δy) | 0.7 mm |
| Angular Compensation (Δa) | 0.5° |
| Axial Compensation (Δx) | 1.4 mm |
| Rotational Inertia | 0.008 kg·m² |
| Mass | 2.6 kg |
Dimension Reference
Coupling Assembly and Slider Block
The SL90 slider block engages the two hub faces through precision-machined tongue-and-groove features. The tongue dimensions and groove clearances are controlled to minimise backlash while providing the sliding freedom needed for misalignment compensation. The standard slider block material is an engineering polymer selected for low friction, adequate compressive strength at the operating torque, and dimensional stability across the rated temperature range of -20°C to +70°C. For higher-load or elevated-temperature applications, a metal slider block is available.
Large Radial Compensation
0.7 mm radial offset compensation eliminates the need for precision motor-to-driven equipment alignment on most plant installations, significantly reducing commissioning time and equipment cost.
Constant Velocity Transmission
The Oldham mechanism maintains constant angular velocity ratio between input and output shafts at all rotational positions — unlike universal joint couplings which produce cyclic velocity variation proportional to operating angle.
Replaceable Wear Element
The slider block is the only wear element in the coupling. It can be inspected and replaced without removing either hub from its shaft, minimising maintenance downtime and hub replacement cost.
No Radial Force Transmission
The sliding mechanism absorbs shaft offset without transmitting significant radial forces to the connected shaft bearings — protecting motor bearings and driven equipment bearings from misalignment-induced overload.
Manufacturing and Quality
Typical Applications
- Compressor drive connections — accommodating frame distortion under reciprocating compressor dynamic loading
- Paper machine roll drive connections — large radial compensation for thermal and gravitational offset
- Marine deck equipment drives — hull flexure and structural movement compensation
- Mining equipment drive connections — frame deflection compensation in mobile crushing equipment
For enquiries about large volume supply or custom bore configurations, visit our contact page.
Customer Reviews and Case Studies
★★★★★
United Kingdom — Printing Machine OEM
The SL90 Oldham coupling connects print roller drives on our digital printing machines. Radial misalignment compensation prevents motor bearing overload from assembly offset, and the coupling transmits the 250 N·m sustained drive torque reliably.
— Lead Engineer, Birmingham
★★★★★
South Korea — Food Conveyor Equipment
Installed in food conveyor drive connections. The SL90 handles our operating torque with the misalignment compensation needed in our modular conveyor frame system.
— Equipment Engineer, Busan
★★★★☆
Canada — Pharmaceutical Packaging
Used on tablet blister pack machine drive connections where shaft offset from assembly tolerance must not load servo motor bearings.
— Validation Engineer, Toronto
Frequently Asked Questions
What is the maximum operating speed for the SL Type coupling?
Maximum operating speed varies by model: SL70 to SL260 are rated to 250 rpm; SL280 to SL460 are rated to 70–100 rpm. These limits reflect the increasing size and sliding distance of the intermediate block at higher speeds. Check the specification table for the precise speed limit of your model.
Can the SL Type coupling accommodate both radial and axial misalignment simultaneously?
Yes. The SL Type coupling accommodates radial and axial displacement simultaneously. The axial compensation is provided by the axial sliding freedom between the hub face and the slider block, in addition to the radial compensation. Axial compensation values range from 1.2 mm for SL70 to 7.2 mm for SL460.
How do I select the correct SL Type model for my application?
Selection is based on three criteria: (1) transmitted torque — select the model whose nominal torque Tn exceeds your application torque multiplied by a service factor of 1.25 to 2.0 depending on load uniformity; (2) bore diameter — confirm the required shaft diameter falls within the model’s bore range; (3) misalignment — confirm the radial offset and angular deviation at your installation are within the rated compensation values.
How long does the slider block (intermediate element) last?
Slider block service life depends on operating speed, misalignment level, transmitted torque, and operating temperature. Under normal operating conditions within rated parameters, polymer slider blocks typically last several years. Operation at maximum misalignment or maximum load simultaneously will reduce service life. The slider block is a replaceable wear element and can be replaced without removing the hubs from the shafts.
What shaft bore tolerances are used for the SL Type coupling?
Hub bores are machined to H7 tolerance as standard, suitable for shaft end tolerances of h6 or k6. The bore range for each model is specified in the technical table — shafts within this range can be accommodated in the same hub without modification.
Enquire About the SL90 SL Type Oldham Coupling
Ever Power manufactures the SL90 and the complete SL Type coupling range — 17 sizes from SL70 to SL460 — direct from our production facility. Provide your bore diameter, operating torque, shaft speed, and misalignment data for a prompt technical and commercial response.
