Description
WH6 Light-Industrial Cast-Iron Oldham Coupling — Mid-Heavy Compressor, Gearbox and Agricultural Drive Joint
The WH6 light-industrial Oldham coupling steps into the mid-heavy light-industrial territory. With 500 N·m rated torque, 30–45 mm bore range, 9.5 kg mass, and 3 800 rpm permissible speed, the WH6 covers small reciprocating-compressor main drives, gear-reducer output couplings, light agricultural machinery principal shafts, and the mid-heavy-end pump and blower drives that form the foundation of global light-industrial infrastructure. At 9.5 kg, the WH6 is at the upper practical limit of single-technician handling without hoist support, and the 45 mm maximum bore corresponds to the dominant shaft size in the 4–7.5 kW motor class that anchors the WH6’s principal application population.
For reciprocating-compressor applications specifically, the WH6 delivers an engineering advantage that rigid and jaw couplings cannot match: shock-load absorption. Reciprocating compressors produce periodic torque spikes — typically 2–3× the average torque at each cylinder-firing event — that accumulate fatigue damage in rigid-coupling flanges and jaw-coupling spiders over time. The WH6’s steel slider absorbs these torque spikes through controlled friction at the sliding interface, producing a more consistent torque transmission that is gentler on the compressor crankshaft bearings and drive-end components. Combined with the WH6’s misalignment tolerance, this makes the cross-slider Oldham architecture the preferred engineering choice for small reciprocating-compressor installations where bearing life and component durability are operational priorities.
Specifications
| Parameter | Value |
|---|---|
| Model | WH6 |
| Nominal Torque (Tn) | 500 N·m |
| Permissible Speed (n) | 3 800 rpm |
| Bore Range (d) | 30 – 45 mm |
| Mass | 9.5 kg |
| Radial Misalignment (Δy) | 0.6 mm |
| Angular Misalignment (Δα) | 0.5° |
| Axial Misalignment (Δx) | 0.7 mm |
| Hub Material | HT200 grey cast iron |
| Slider Material | Hardened carbon steel |
| Lubrication | Grease (annual) |
| Shaft Engagement | Keyway + setscrew |
Materials
HT200 Cast-Iron Hubs
Precision-machined HT200 grey cast-iron hubs. At the WH6’s 9.5 kg total mass, each hub contributes approximately 4.5 kg — at the practical limit of single-person handling without support equipment. Hub section thickness is conservatively engineered, providing a substantial safety factor against the 500 N·m torque rating and shock-load events of reciprocating-compressor duty.
Hardened Steel Slider — Shock Absorber
Induction-hardened carbon steel cross-slider. At the WH6’s mid-heavy duty class, the slider’s shock-load absorption function becomes as important as its misalignment accommodation. The slider dissipates reciprocating-compressor torque spikes through controlled friction at four sliding faces, smoothing the transmitted torque waveform and reducing peak-load exposure on the compressor’s drive-end bearings.
Keyway + Setscrew (M10)
H7-reamed bore with parallel keyway and M10 set-screw for axial location. For agricultural-machinery applications with seasonal hub removal and shaft-inspection requirements, the standard keyway bore is supplemented by clamp-collar adapters on engineering enquiry, providing convenient removal-and-reinstall capability without hub modification.
Reciprocating-Compressor Torque-Spike Absorption
Single-cylinder and twin-cylinder reciprocating compressors produce a characteristic periodic torque waveform at the drive coupling. Each cylinder-firing event creates a sharp torque peak — typically 200–300 % of the average transmitted torque — at a frequency determined by the number of cylinders and the compressor rotational speed. At 3 800 rpm with a single-cylinder compressor, this translates to 63 torque spikes per second, each imposing a fatigue event on any non-absorbing coupling in the drive train.
A rigid coupling transmits these spikes unchanged into the motor-output shaft and motor bearings; after sufficient cycles, bearing fatigue damage accumulates into a bearing failure. A spider coupling absorbs some spikes through elastomer deflection, but the elastomer itself accumulates fatigue damage from each event. The WH6’s cross-slider architecture absorbs each torque spike through a controlled friction event at the slider-hub interface — a reversible mechanical process that produces no cumulative damage in the coupling components. The net result is extended motor bearing life, extended compressor crankshaft bearing life, and predictable long-interval slider replacement that gives the maintenance team control over the coupling’s service cycle. For further discussion of compressor coupling selection, see Ever-power’s compressor-coupling guide.
Industry Applications
Small Reciprocating Compressors
Main-drive coupling on 4–7.5 kW single-cylinder and twin-cylinder reciprocating air and gas compressors. Torque-spike absorption extends motor and compressor bearing life.
⚙️ Gear-Reducer Output Coupling
Output-shaft to driven-machine coupling on light-duty gear-reducer installations across general industry. Near-zero-backlash supports consistent driven-equipment positioning.
Light Agricultural Machinery
Principal-shaft drives on small grain-augers, silage-cutters, and feed-mixer main drives. Seasonal-duty ambient compatibility through annual grease-maintenance schedule.
Mid-Heavy Pump Drives
Motor-to-pump coupling on medium-duty centrifugal and positive-displacement pumps in the 4–7.5 kW motor class for municipal, industrial, and process-plant applications.
️ Light Construction Equipment
Drive couplings on concrete-mixer drums, small-aggregate conveyor drives, and construction-site compactor main shafts. Impact-absorption capability handles the duty profile of light construction equipment.
Legacy Coupling Retrofit
Drop-in replacement on legacy compressor, gear-reducer, and pump installations where the original specification has been discontinued or has underperformed. Bore range covers dominant shaft sizes in the 4–7.5 kW class.
Why Choose Ever-power
Quality & Compliance
WH6 production runs under ISO 9001:2015. Documentation covers RoHS, REACH, and CE conformity. For compressor and construction-equipment OEM customers, supplementary shock-load absorption documentation is available to support product-engineering specifications. Cast-iron material compliance certificates supplied as standard.
Cost Economics
The WH6 is positioned as the economical metallic-slider alternative to spider couplings and rigid flanges in the mid-heavy light-industrial market. Hub-only, slider-only, and full-coupling supply options provide maximum flexibility for retrofit and OEM applications. Volume pricing for OEM customers and distributor-programme pricing for stocking distributors are supported.
Aftermarket
WH6 sliders and hubs stocked for 2-business-day shipment. 9.5 kg mass requires courier with weight-limit clearance; standard industrial freight routinely available. English-speaking engineering desk responds within 24 hours.
Customer Reviews & Case Studies
★★★★★
Mali — Cold-Storage Facility Operator
Used in: Reciprocating-compressor main-drive coupling on single-stage air compressors for a refrigerated-storage facility.
Feedback: “Compressor bearing failures had been occurring at 18-month intervals under rigid-coupling specification. After retrofit to WH6 across 6 compressor units, we have now completed 4 years without a single compressor bearing failure. The torque-spike absorption benefit is real and visible in our maintenance data. Total ownership cost for the compressor drive train has reduced substantially.”
★★★★★
Mauritania — Grain-Processing Operator
Used in: Main-shaft drive coupling on grain-auger and elevator drives at a commercial grain-storage facility.
Feedback: “Seasonal grain-handling duty with high-ambient-temperature operation (45+ °C summer). The WH6 has handled 5 grain-handling seasons without coupling-related downtime. Annual grease repack at the start of each season is the entire maintenance footprint. Excellent reliability and value for commercial grain-handling applications.”
★★★★☆
Lesotho — Highland Water-Infrastructure Contractor
Used in: Gear-reducer output coupling on mountain-water-supply pump stations serving high-altitude communities.
Feedback: “High-altitude operation (2 800 m elevation) with temperature extremes (-10 °C winter / +30 °C summer). The WH6 has performed without issue for 4 years. Knock one star only because the grease specification guidance for extreme-temperature-range environments could be more visible in the standard product documentation — we needed to contact engineering for clarity on winter-grade grease specification. Response was prompt and helpful.”
Frequently Asked Questions
How does the WH6 handle reciprocating-compressor shock loads?
The steel cross-slider dissipates each cylinder-firing torque spike through a controlled friction event at the four sliding hub interfaces. Unlike elastomer-based couplings (which store and release elastic energy) or rigid couplings (which transmit spikes unchanged), the WH6’s metallic slider acts as a mechanical low-pass torque filter — smoothing the transmitted waveform and reducing peak loads on downstream bearings. The friction work is small per event but cumulative friction heat is also minimal at the WH6’s operating speed.
Is the WH6 suitable for construction-site environments?
Yes, with appropriate dust protection. Construction-site environments include cement dust, silica particles, and fine grit that can accelerate slider wear if they penetrate the sliding interface. For construction-site deployments, specify a sealed coupling guard to IP55 or better, and shorten grease-repack intervals to 6 months to flush any ingested particulate from the slider interface. With these measures, the WH6 has documented reliable service in construction-site compressor and concrete-mixer applications.
What winter-grade grease is recommended for cold-climate installations?
For installations where ambient temperature drops below -10 °C during operation, specify a synthetic polyalphaolefin (PAO) base grease with NLGI Grade 0 or 00 consistency — such as Fuchs Renolin Unimoly L0 or equivalent. Standard NLGI Grade 2 lithium-complex grease becomes too viscous below -10 °C to maintain adequate film formation at start-up, potentially causing elevated friction until the grease warms. PAO grade 0 maintains adequate film formation to approximately -35 °C start-up temperature.
What is the expected slider service life on compressor duty?
Under typical single-stage reciprocating-compressor duty (500 N·m average torque, 3 600 rpm, 0.2–0.3 mm parallel offset), WH6 slider service life is typically 5–7 years before wear-induced clearance increase produces acceptable backlash. Annual grease repack and visual inspection during each repack are the key maintenance actions for service-life management. Compressor-duty slider wear typically shows on the long axis of the slider cross-piece, and is clearly visible during inspection without measurement tools.
Can the WH6 be used on belt-driven agricultural machinery?
Yes. For agricultural machinery with belt-drive between motor and WH6 coupling, the cross-slider architecture accommodates the misalignment and torque variation that belt drives introduce. Ensure the coupling guard allows adequate airflow for the belt-drive system and does not interfere with belt-tension adjustment. For very high-shock-load agricultural applications (feed chopper main drives, silage cutter direct-drives), consider upgrading to the WH7 for additional torque reserve.
Quote WH6 for Compressor and Mid-Heavy Drives
For small reciprocating-compressor, gear-reducer output, agricultural-machinery, and mid-heavy pump-drive applications, the WH6 delivers torque-spike absorption and bearing-life extension that rigid and spider couplings cannot match. Browse the wider WH series catalogue, read about Ever-power’s industrial-coupling supply capability, or enquire directly below.