6K-310 6K-625 6K-800 6K-985 Eaton Hydraulic Motor Drilling Rig

Product Overview

The 6K Series orbital hydraulic motors (including 6K-310, 6K-625, 6K-800, 6K-985, and 6K-390) are direct drop-in interchange products for the Eaton Char-Lynn® 6000 Series disc valve Geroler® motors, widely applied in coal mine drilling rigs, water well drilling rigs, horizontal directional drilling (HDD) rigs, fishing vessel winches, and construction machinery. The series features an advanced end-face disc valve cycloidal structure with column-embedded stator-rotor parameters, covering geometric displacements from 195 to 985 cm³/rev, with continuous working pressures up to 17 MPa and maximum continuous output torque reaching 1570 N·m.

The series’ core drivetrain design utilizes double tapered roller bearings supporting the output shaft, capable of simultaneously accommodating high combined axial and radial loads, ensuring sufficient structural rigidity when the motor directly drives winch drums or drilling rig power heads. The disc valve utilizes long and short spline shafts to separately transmit rotor rotation and orbital motion to the output shaft and valve plate respectively, achieving continuous alternation of high and low pressure oil through synchronized valve plate operation for smooth torque and speed output. Changing the inlet flow direction reverses the motor rotation direction.

The series achieves drop-in interchangeability with Eaton Char-Lynn 6000 Series (including 6K-195, 6K-245, 6K-310, 6K-390, 6K-490, 6K-625, 6K-800, 6K-985), while remaining compatible with Danfoss OMT Series, M+S MT Series, and BMK6/BM6/OMT equivalents. Mounting flange, port positions, and output shaft specifications remain consistent with originals for direct replacement without modifying piping or mounting brackets. The series is suitable for agricultural machinery, fishing machinery, plastic industry, mining, and construction machinery, achieving the best combination of high efficiency and economy in medium-duty applications.

Every motor undergoes 100% simulated load testing before shipment, with protocols covering output torque verification at rated pressure, volumetric efficiency measurement at multiple speed points, internal leakage testing, and overspeed validation.

Technical Specifications 

Basic Specifications

• Model: 6K-310 / 6K-625 / 6K-800 / 6K-985 (including 6K-390)

• Motor Type: End-Face Disc Valve Orbital Motor (Geroler)

• Product Series: Eaton Char-Lynn® 6000 Series Interchange

• Gear Set Type: Column-embedded stator-rotor (Geroler)

• Valve System: Disc valve with automatic wear compensation

• Mounting Flange: 4-Bolt Square Flange (Pilot Ø127 mm, Hole Ø13.5 mm)

• Shaft Type: Ø38.1 mm 17T Spline / Tapered / Cylindrical

• Port Size: 7/8″-14 UNF SAE O-Ring / G1/2

• Drain Port: 7/16″-20 UNF

• Bearings: Double tapered roller bearings, high radial load capacity

• Seals: High-pressure shaft seal (HPS), series circuit capable

• Allowable Back Pressure: 10 MPa (recommended ≤5 MPa, drain line required if exceeded)

6K-310 Performance Data (310 cm³/rev)

• Geometric Displacement: 310 cm³/rev [18.9 in³/rev]

• Max. Speed (Continuous): 485 rpm

• Max. Speed (Intermittent): 698 rpm

• Max. Pressure Drop (Continuous): 17 MPa (170 bar / 2973 psi)

• Max. Pressure Drop (Intermittent): 27.5 MPa (275 bar / 4496 psi)

• Max. Torque (Continuous): 775-930 N·m

• Max. Torque (Intermittent): 1225-1355 N·m

• Max. Flow (Continuous): 150 L/min

• Max. Flow (Intermittent): 225 L/min

• Weight: Approx. 29.2 kg

6K-390 Performance Data (390 cm³/rev)

• Geometric Displacement: 390 cm³/rev [23.8 in³/rev]

• Max. Speed (Continuous): 387 rpm

• Max. Speed (Intermittent): 570 rpm

• Max. Pressure Drop (Continuous): 17 MPa (170 bar)

• Max. Pressure Drop (Intermittent): 27.5 MPa (275 bar)

• Max. Torque (Continuous): 965-1155 N·m

• Max. Torque (Intermittent): 1455-1635 N·m

• Max. Flow (Continuous): 150 L/min

• Max. Flow (Intermittent): 225 L/min

• Weight: Approx. 30.0 kg

6K-625 Performance Data (625 cm³/rev)

• Geometric Displacement: 625 cm³/rev [38.1 in³/rev]

• Max. Speed (Continuous): 241-307 rpm

• Max. Speed (Intermittent): 355-454 rpm

• Max. Pressure Drop (Continuous): 14-17 MPa (140-170 bar)

• Max. Pressure Drop (Intermittent): 17-27.5 MPa (170-275 bar)

• Max. Torque (Continuous): 1215-1330 N·m

• Max. Torque (Intermittent): 1380-1885 N·m

• Max. Flow (Continuous): 150 L/min

• Max. Flow (Intermittent): 225 L/min

• Weight: Approx. 32.1 kg

6K-800 Performance Data (800 cm³/rev)

• Geometric Displacement: 800 cm³/rev [48.8 in³/rev]

• Max. Speed (Continuous): 184 rpm

• Max. Speed (Intermittent): 276 rpm

• Max. Pressure Drop (Continuous): 12 MPa (120 bar)

• Max. Pressure Drop (Intermittent): 14 MPa (140 bar)

• Max. Torque (Continuous): 1380 N·m

• Max. Torque (Intermittent): 1650 N·m

• Max. Flow (Continuous): 150 L/min

• Max. Flow (Intermittent): 225 L/min

• Weight: Approx. 32.5 kg

6K-985 Performance Data (985 cm³/rev)

• Geometric Displacement: 985 cm³/rev [60.1 in³/rev]

• Max. Speed (Continuous): 153 rpm

• Max. Speed (Intermittent): 230 rpm

• Max. Pressure Drop (Continuous): 12 MPa (120 bar)

• Max. Pressure Drop (Intermittent): 14 MPa (140 bar)

• Max. Torque (Continuous): 1570 N·m

• Max. Torque (Intermittent): 1875 N·m

• Max. Flow (Continuous): 150 L/min

• Max. Flow (Intermittent): 225 L/min

• Weight: Approx. 33.5 kg

Full 6K Series Displacement Range

• 6K-195: 195 cm³/rev, 775 rpm continuous, 475-575 N·m continuous torque

• 6K-245: 245 cm³/rev, 615 rpm continuous, 615-735 N·m continuous torque

• 6K-310: 310 cm³/rev, 485 rpm continuous, 775-930 N·m continuous torque

• 6K-390: 390 cm³/rev, 387 rpm continuous, 965-1155 N·m continuous torque

• 6K-490: 490 cm³/rev, 307 rpm continuous, 1058-1215 N·m continuous torque

• 6K-625: 625 cm³/rev, 241 rpm continuous, 1215-1330 N·m continuous torque

• 6K-800: 800 cm³/rev, 184 rpm continuous, 1380 N·m continuous torque

• 6K-985: 985 cm³/rev, 153 rpm continuous, 1570 N·m continuous torque

Interchange Reference

• Eaton Char-Lynn 6000 Series: 112-1060-006 (310), 112-1061-006 (390), 112-1062-006 (490), 112-1109-006 (625), 112-1063-006 (985)

• Danfoss OMT Series: OMT160, OMT200, OMT250, OMT315, OMT400, OMT500

• Other Interchange: BMK6 / BM6 / OMT / HMT / M+S MT Series

Materials & Construction

• Housing: High-strength cast iron

• Gear Set: Column-embedded stator-rotor (Geroler), carburized and hardened alloy steel

• Valve Mechanism: Disc valve with automatic wear compensation

• Bearings: Double tapered roller bearings, high radial load capacity

• Seals: High-pressure shaft seal, series circuit capable

Key Technical Advantages

1. Disc Valve Architecture with Automatic Wear Compensation

The 6K Series features an end-face disc valve structure, with long and short spline shafts driving the rotor and valve plate synchronously. During operation, the valve plate is continuously pressure-loaded against the stator-rotor end face, achieving automatic wear compensation—as operating hours accumulate, the valve plate automatically adjusts its position based on system pressure to maintain sealing clearance, ensuring volumetric efficiency remains stable throughout the service life. This structural design enables the motor to maintain high efficiency at low speeds, with volumetric efficiency consistently above 90%. Compared to spool valve designs, the disc valve offers superior leakage control at high displacement operating conditions.

2. Double Tapered Roller Bearings with High Radial Load Capacity

The output shaft is supported by double tapered roller bearings capable of simultaneously accommodating high axial and radial forces. The line-contact load-bearing mode of tapered roller bearings provides significantly higher radial load capacity than ball bearings, suitable for applications involving direct drive of winch drums, sprockets, or gears. Bearing preload is precisely controlled during assembly to prevent excessive shaft deflection under radial loads, preserving long-term gear mesh precision and shaft seal reliability. This design enables 6K Series motors to be used in traction drive applications on heavy vehicles and machinery.

3. High-Pressure Shaft Seal with Series Circuit Compatibility

The 6K Series is equipped with a high-pressure shaft seal designed for elevated pressure capability, allowing the motor to operate in series circuits without an additional drain line (provided back pressure does not exceed recommended limits). Allowable back pressure reaches 10 MPa, with recommended operating back pressure not exceeding 5 MPa; a drain line is required if exceeded. This characteristic makes the series particularly suitable for hydraulic systems with multiple coordinated actuators, such as fishing vessel winches and drilling rigs, simplifying circuit layout and reducing installation costs and leak risks.

4. Broad Interchangeability and Multi-Platform Compatibility

The 6K Series achieves drop-in interchangeability with Eaton Char-Lynn 6000 Series, while remaining compatible with Danfoss OMT Series, M+S MT Series, and BMK6/BM6/OMT equivalents. Mounting flange (4-bolt square flange, Pilot Ø127 mm), port positions (7/8″-14 UNF), and output shaft specifications (Ø38.1 mm 17T spline) remain consistent with originals for direct replacement without modifying piping or mounting brackets. The series covers eight continuous displacement sizes from 195 to 985 cm³/rev, providing exceptional selection flexibility for equipment manufacturers.

5. 100% Simulated Load Testing & Batch Consistency

Every 6K Series motor undergoes 100% simulated load testing before shipment. Test protocols cover output torque verification at rated pressure, volumetric efficiency measurement at multiple speed points, internal leakage testing, overspeed validation, and noise assessment. All test data is archived and traceable, ensuring each motor’s performance matches its published specifications.

Application Areas

• Coal Mine Drilling Rigs: Power head rotary drive, tunnel drilling rig drive (6K-310 typical application)

• Water Well Drilling Rigs: Power head cycloidal hydraulic motor drive

• Horizontal Directional Drilling (HDD) Rigs: Power head rotary drive (6K-390/490 typical applications)

• Fishing Vessel Winches: Winch drive, net hauler drive, marine deck machinery drive

• Construction Machinery: Road roller drive, concrete mixer drive, crane slewing drive

• Agricultural Machinery: Combine harvester travel drive, sugarcane harvester drive

• Industrial Equipment: Injection molding machine rotary drive, conveyor drive, cleaning equipment

• Snow Removal Equipment: Snow sweeper brush drive, snow blower drive

Expert Maintenance Tips

1. Mounting Fit and Bolt Torque

Before installation, verify that the 4-bolt square flange (Pilot Ø127 mm, Hole Ø13.5 mm) and machine mounting bore conform to H8/f7 tolerance fit. Tighten mounting bolts in diagonal sequence in 2-3 stages to the specified torque. When the output shaft is a Ø38.1 mm 17T splined shaft, ensure spline engagement length is no less than 80% of total spline length to avoid localized stress concentration. Use 7/8″-14 UNF SAE O-ring seals for port connections; recommended tightening torque is 55-65 N·m. The drain port is 7/16″-20 UNF with recommended tightening torque of 20-25 N·m. When the motor is subject to radial loads, ensure the machine mounting base has sufficient rigidity to withstand reaction torque from bearing loads.

2. Case Drain Piping

In series circuits, a case drain line is mandatory when system return back pressure exceeds 5 MPa. The allowable back pressure limit is 10 MPa, but recommended operating back pressure should not exceed 5 MPa to extend shaft seal life. The case drain must be piped separately to the reservoir—never connected in parallel with the main return line. Case drain back pressure should be maintained below 0.5 bar. Periodically inspect drain flow; a significant increase may indicate wear in the shaft seal or valve plate, requiring prompt shutdown and inspection.

3. System Flushing and Oil Cleanliness

After initial installation or motor replacement, run the motor for 1 hour at 40% of maximum working pressure before running at full load. System oil cleanliness should meet ISO 18/13 or NAS 9 or better. A 10 μm return-line filter is recommended. N68 anti-wear hydraulic oil with viscosity range 37-73 cSt is recommended, with maximum operating temperature not exceeding 80°C. For 6K-800 and larger displacement models, flushing flow should reach at least 1.5 times the motor’s rated flow.

4. Storage and Extended Shutdown

For long-term storage, install port plugs to prevent contamination and fill the motor with clean hydraulic oil. Store at temperatures between -20°C and +50°C, away from direct sunlight and moisture. Motors stored for more than 6 months should undergo an internal leakage check before installation. For splined shaft models, pay particular attention to spline protection during storage—apply anti-rust grease to the splined section.