The NACD SP214AM and SP314AM Series Power Take-Offs (PTOs) are engine-mounted disconnect clutches designed for agricultural and industrial applications. These PTOs feature cast iron one-piece housings and an integral 14-inch diameter clutch.
Function Description:
The engine drives the clutch through a drive ring bolted to the engine flywheel. This drive ring connects to the clutch via internal teeth that mesh with external teeth on the clutch friction plate(s). Clutch engagement and disengagement are typically achieved using an external hand lever assembly, though some units may employ other actuation methods.
The output components of the PTO include a clutch hub mounted on the output shaft, a linkage mechanism for clutch engagement and disengagement, and clutch adjustment components. In multi-plate clutch designs, a clutch center plate is positioned between the driving plates. Both the clutch center plate and pressure plate are driven by internal teeth that mesh with external teeth on the clutch hub. Before clutch engagement, the output components remain stationary.
During clutch engagement, the clutch pressure plate moves to clamp the clutch friction plate(s) against the friction face of the clutch hub (or center plate(s)). The internal engagement mechanism then locks the clutch pressure plate in the engaged position, completing the drive. When fully engaged and the engine is running, the output shaft rotates at engine speed.
Important Technical Specifications:
- Clutch Diameter: 14 inches
- Maximum Safe Operating Speeds:
- SP114AM Series: 3000 RPM
- SP214AM Series: 3000 RPM
- SP314AM Series: 3000 RPM
- These speeds apply to units with grease-lubricated main bearings and ductile iron drive rings with solid drive plates.
- SAE Housing Identification (SAE Hsg No. 1):
- A: 511.18 mm (20.125 inches)
- B: 552.4 mm (21.75 inches)
- C: 530.22 mm (20.875 inches)
- D (Dia.): 12.29 mm (0.484 inches)
- Qty.: 12
- Roller-Type Pilot Bearing Dimensions:
- 101578AM: O.D. 72 mm (2.835 in.), Nominal Width (C) 30.1 mm (1.185 in.), Nominal Width +/- Tolerance 0.5 mm (0.020 in.)
- 101653AM: O.D. 80 mm (3.15 in.), Nominal Width (C) 34.86 mm (1.3725 in.), Nominal Width +/- Tolerance 0.5 mm (0.020 in.)
- 101848AM: O.D. 100 mm (3.94 in.), Nominal Width (C) 39.62 mm (1.5600 in.), Nominal Width +/- Tolerance 0.5 mm (0.020 in.)
- Recommended Bearing End Play (Tapered Roller Bearings):
- Side-Loaded Applications (SP114AM, SP214AM, SP314AM Series): 0.15 - 0.25 mm (0.006 - 0.010 inches)
- In-Line Applications (SP114AM, SP214AM, SP314AM Series): 0.23 - 0.30 mm (0.009 - 0.012 inches)
- Required Torque on Operating Shaft to Engage Clutch (SP114AM, SP214AM, SP314AM Series): 295 - 391 Nm (218 - 289 Lb.-Ft.)
- PTO Deflection: Should not exceed 0.254 mm (0.010 in.) (T.I.R.) at the bearing carrier.
- Support Plate Dimensions (SP214AM and SP314AM Series):
- Bore Dia. A: 190.50 mm (7.50 in.) (+.127/0.25mm or +.005/+.001")
- Bolt Circle (Dia.) B: 225.43 mm (8.875 in.)
- Radius C: 127.0 mm (5.0 in.)
- Degree D: 30°
- Hole Qty. E: 6
- Hole Dia. F: 17/32 in.
- Recommended Thickness G: 12.70 mm (0.500 in.)
- Engaging Stroke Travel at 25.4 mm (1 in.) (Cylinder):
- SP114AM, SP214AM Series: 7.925 mm (0.312 inches)
- SP314AM Series: 7.950 mm (0.313 inches)
- Engaging Force Required at Cylinder at 25.4 mm (1 in.) (SP114AM, SP214AM, SP314AM Series): 14012 Newtons (3150 pounds)
Usage Features:
- Installation Tips: Proper installation is crucial for longevity. Tapered roller bearing end play must be adjusted correctly for either side-load or in-line applications. Flywheel and flywheel housing alignment must be within specifications, and crankshaft endplay should be checked before and after PTO installation to prevent interference. Excessive misalignment between the engine and PTO should be avoided, and deflection under operating conditions should not exceed 0.254 mm (0.010 in.) T.I.R.
- Drive Ring Installation: The drive ring must be clean, free of imperfections, and properly torqued to the flywheel.
- Pilot Bearing Installation: Ball-type pilot bearings should be tapped onto the clutch shaft, applying force only to the inner race. Roller-type pilot bearings require careful installation, often involving heating the inner race and pressing it onto the shaft, ensuring proper axial alignment.
- Support Plate: A customer-supplied support plate may be required for side-load applications to support the output end of the PTO housing.
- Belt or Chain Tension: Avoid excessively tight or loose belts/chains to prevent bearing failure and shortened service life.
- Hand Lever Position: For horizontal operating shafts, the hand lever should be slightly past the vertical position, towards the engine, when the clutch is engaged to prevent preload on the shifting mechanism. For vertical operating shafts, a stop collar is necessary to prevent preload from the hand lever's weight.
- Air Engagement Mechanisms: Air engagement systems must be properly installed and adjusted to provide correct engagement force and stroke, ensuring no preload on the throwout bearing in fully engaged or released positions.
- Clutch Engagement Procedure:
- Normal Engagement: Engage the clutch quickly at the lowest possible engine RPM (below 1,000 RPM) to minimize slippage.
- High Inertia Loads: For high inertia loads, engagement may occur at higher RPMs, potentially requiring a series of short engagements and disengagements to gradually increase load speed and prevent excessive heat buildup.
- Jammed Devices: Never engage the PTO to unjam a stuck load. Always shut off the engine, disengage the clutch, and clear the jam manually.
Maintenance Features:
- Tapered Roller Bearing Adjustment: Periodically check for excessive shaft movement and adjust end play according to specifications (0.15-0.25 mm for side-load, 0.23-0.30 mm for in-line applications).
- Lubrication:
- Grease Specifications: Use NLGI Grade 2 Lithium grease with a minimum 149° C (300° F) drop point.
- Main Bearings (SP114AM, SP214AM, SP314AM Series): Apply 1 cc of grease before start-up and every 100 hours of operation thereafter through the fitting on the bearing carrier.
- Operating Shaft Fittings (SP114AM, SP214AM, SP314AM Series): Apply 1 cc of grease before starting and every 3 months or 500 hours of operation (whichever comes first).
- Throwout Collar (SP114AM, SP214AM, SP314AM Series): Apply 1 cc of grease daily before start-up and every 8-10 hours of operation thereafter through the fitting on the tapered part of the housing.
- Pilot Bearings (Sealed): Pre-lubricated and sealed for life; no maintenance required, but inspection is recommended every two years or when the PTO is removed for servicing.
- Clutch Linkage: Lubricate the clutch linkage mechanism, cotter pins, clevis pins, and levers with engine oil every 500 hours of operation. Avoid over-greasing to prevent oil from splashing onto friction plates.
- Clutch Adjustment: Check clutch adjustment regularly, especially for new PTOs (before service and after the first 8-10 hours) and units with new friction plates. More frequent adjustments are needed for heavy-duty applications. Adjust the clutch before it overheats, loses pull, or the operating lever jumps from engagement.
- Cleaning and Inspection:
- Bearings: Wash in clean solvent, inspect for roughness, corrosion, scores, cracks, pits, chips, or excessive wear. Protect clean bearings from contaminants.
- Housings, Cast Parts, Machined Surfaces: Replace cracked parts. Inspect bearing bores for grooves, burrs, or galling. Remove imperfections with crocus cloth. Inspect bores for wear and obstructions in oil/grease passages.
- Shafts, Seal Lip Contact Surfaces, Bearing Journals: Inspect machined surfaces for burrs, scratches, nicks, and foreign matter. Replace parts if defects cannot be removed. Inspect pilot bearing journal for wear or signs of turning. Ensure snap ring grooves have straight sides.
Need help?
General
To Next Page