Hydromatik Rexroth HDT Series Hydraulic Motor | HDT75 HDT108 HDT-ISO

The HDT Series fixed displacement bent-axis axial piston hydraulic motors manufactured by Chengyuan Hydraulic are premium, heavy-duty fluid power execution modules fully engineered to match global Hydromatik / Rexroth engineering benchmarks. Celebrated across the mobile and industrial fluid power sectors for delivering exceptional power density, superior starting torque efficiency, and unyielding reliability under high-frequency shock loads, this series serves as a critical powerplant in both open and closed-circuit networks. The comprehensive product matrix specifically targets the primary displacement and configuration array: HDT75D, HDT75S, HDT84D, HDT84S, HDT96S, HDT108D, HDT108S-R, and the standardized industrial interface configuration HDT-ISO-108D(R) (matching industry cross-references such as 601 001 10643). Within the code designation, S and D specify single or bi-directional valve plate and port configurations, R mandates clockwise rotation, and the ISO identifier ensures full compliance with international 4-bolt flanges and metric splined shaft boundaries. Every single HDT motor undergoes 100% dynamic test-bench evaluation under full high-pressure ratings for mechanical output efficiency, minimum-RPM stall torque ripple tracking, casing drain line sealing integrity, and complete volumetric calculation prior to shipment to ensure matching original parameters, delivering proven 100% original-place interchangeable compatibility.

Technical Specifications:

• Core Product Framework: Hydromatik Rexroth HDT Series Template High-Pressure Bent-Axis Fixed Displacement Piston Motors

• Displacement Family Matrix: HDT75 / HDT84 / HDT96 / HDT108 (Including ISO Architecture)

• Model Configurations Supported: HDT75D / HDT75S / HDT84D / HDT84S / HDT96S / HDT108D / HDT108S-R / HDT-ISO-108D(R)

• Geometric Volumetric Displacements:

  • HDT75 Specifications: 75.3 $cm^3/rev$

  • HDT84 Specifications: 84.2 $cm^3/rev$

  • HDT96 Specifications: 96.4 $cm^3/rev$

  • HDT108 Specifications: 107.5 $cm^3/rev$

• Operational Pressure Envelopes:

  • Nominal Continuous Pressure Rating: 350 bar (35 MPa / 5075 psi)

  • Intermittent Maximum System Peak Limit: Reaches up to 400 bar (40 MPa / 5800 psi)

• Maximum Allowable Rotational Speeds:

  • HDT75 Profile: Continuous rating up to 3400 rpm (intermittent peak up to 3800 rpm)

  • HDT108 Profile: Continuous rating up to 2800 rpm (intermittent peak up to 3150 rpm)

• Maximum Output Torque (at $\Delta p = 350 \text{ bar}$ continuous pressure drop):

  • HDT75 Profile: Rated torque output at 419 N·m

  • HDT108 Profile: Rated torque output at 598 N·m

• Mechanical Interface Standards: Built fully to ISO standard 4-bolt square or rhombic mounting geometries; standard input shaft options feature DIN 5480 involute splines (seamlessly matching 601 001 10643 system interfaces).

• Efficiency Baselines: Rated at $\ge 97\%$ for volumetric efficiency and $\ge 92\%$ for overall mechanical operating efficiency under full load.

Key Technical Advantages:

• Classic $40^\circ$ Bent-Axis Architecture for High Starting Torque Efficiency: The HDT series utilizes a 40-degree bent-axis configuration. Compared to standard swashplate designs, the bent-axis layout minimizes lateral forces exerted on the pistons by the connecting rods. This design delivers a high starting torque efficiency ($\ge 90\%$), ensuring smooth, powerful actuation when starting under full static loads.

• Monoblock Forged Steel Cylinders with Bimetallic Sintered Valve Interfaces: The rotating cylinder block is forged from a high-strength alloy steel matrix and case-hardened to eliminate micro-structural casting voids. The cylinder-to-lens-plate boundary features a bimetallic copper alloy sintered layer. Precision-lapped to sub-micron spherical mating tolerances, it maintains an optimal hydrostatic oil film that minimizes internal fluid bypass under a continuous 350 bar load.

• Heavy-Duty Tapered Roller Bearings for High Radial & Axial Load Resistance: The input drive shaft is supported by a preloaded pair of heavy-duty tapered roller bearings. This structural layout absorbs severe axial and radial forces from direct external mechanical links like heavy gears, chains, or winches, ensuring precise internal alignment and extending the machine’s service life.

• Acoustically Optimized All-Steel Casting for Low Noise Operation: The motor housing is cast from high-tensile structural steel with wall thicknesses optimized for acoustic damping. The internal fluid channels and porting galleries feature smooth, radius-blended curves that eliminate sharp transitions, reducing fluid shear noise and cavitation whining during high-RPM shifts or pressure spikes.

Application Areas:

• Heavy Construction Machinery Slew & Winch Drives: Rotary drives for crawler excavator superstructures, auxiliary動力头 rotations for rotary drilling rigs, and high-pressure hoist winch motors for crawler cranes.

• Mobile Mobile & Municipal Fleet Infrastructure: High-torque drum drives for concrete mixer trucks, active core brush drives for heavy street sweepers, and specialized hydraulic vehicle recovery winches.

• Marine Marine & Heavy Industrial HPU Stations: Main fluid power blocks for marine anchor windlasses, high-torque industrial conveyor drives, and heavy mining material crushers.

Expert Maintenance Tips:

• Mandatory Housing Case Priming Prior to Initial Machine Activation: The high-speed rolling assemblies, piston joints, and heavy journal bearings within the bent-axis HDT series rely on the fluid reservoir inside the motor case for cooling and lubrication. After mounting, you must fill the motor casing completely with clean, filtered system oil via the highest drain port (Port T), then rotate the shaft by hand for at least 3 turns before startup. Dry-cranking will cause immediate thermal friction welding, destroying the internal rotating groupings within the first few seconds.

• Enforce an Isolated Case Drain Line and Maintain Case Backpressure $\le 2\text{ bar}$: The case drain line for units like the HDT75 or HDT108 must utilize an oversized flexible hose and run directly back to the reservoir below the oil line, completely independent of main system returns or lines with check valves. Maintain a running case internal pressure below 2 bar. Restricting this line causes case over-pressurization, which can burst the shaft seal lip or unseat the cylinder block from the lens plate, leading to a catastrophic loss of volumetric efficiency.

• Maintain Strict Thermal Boundary Controls and Keep Peak Fluid Temperature $\le +85^\circ\text{C}$: Due to the close-tolerance matching inside these bent-axis motors, ensure the active running system temperature remains within the optimal $+30^\circ\text{C}$ to $+60^\circ\text{C}$ band. If sustained heavy loading pushes fluid temperature past $+85^\circ\text{C}$, shut down the circuit immediately or increase cooling efficiency. Excessive heat thins the hydraulic fluid, breaking down the hydrostatic oil film and risking metal-to-metal boundary contact, which can cause severe copper-seizure or cylinder fracturing.