Rexroth VMR Series High-Pressure Relief Valve | A2FE107 A2FE180 Motor Cartridge | R930054929 R930070454

The VMR Series of high-pressure, pilot-operated poppet-type relief and anti-cavitation dual-function valves manufactured by Chengyuan Hydraulic are flagship fluid power components engineered to fully Cross-Reference the rigorous technical blueprints of Bosch Rexroth (Compact Hydraulics/Oil Control lineage). This high-tier control cartridge series is purposely configured to integrate directly into the rear port plates of Rexroth’s signature A2FE107, A2FE125, A2FE160, and A2FE180 bent-axis axial piston fixed plug-in motors, functioning as secondary overpressure security and anti-vacuum safeguards. Focusing on the high-demand original parts index supplied—R930054929, R930070454, R930077359, R931002539, and R930070446—Chengyuan utilizes ultra-precise lap-fitting procedures over hardened structural cores to guarantee 100% original-place interchangeable plug-and-play compatibility. Every valve block is subjected to 100% simulated loaded testing for pressure override limits, flow curves, and high-frequency anti-cavitation check seat sealing before shipping, securing rigid boundary defense under severe 420 bar dynamic envelopes.

Technical Specifications :

• Brand Cross-Reference: Bosch Rexroth (Oil Control Division) VMR Series Equivalent

• Target Part Numbers Covered: R930054929, R930070454, R930077359, R931002539, R930070446

• Host Equipment Compatibility: Rear port plates of Rexroth A2FE107, A2FE125, A2FE160, and A2FE180 hydrostatic plug-in motors

• Cavity Matrix Profiles (Special Cavity): LG Standard (M30x1.5), YHC Standard, LM Standard (M36x2), and YHK Standard

• Maximum System Pressure Rating: 420 bar (42.0 MPa / 6000 psi continuous shock resistance)

• Nominal Passing Flow Capacities:

  • VMR2 Variant Platforms (LG / YHC Cavity e.g., R930054929, R930070454): Up to 240 L/min (63 gpm)

  • VMR3 Variant Platforms (LM / YHK Cavity e.g., R930077359, R930070446): Up to 400 L/min (106 gpm)

• Pressure Adjustment Envelope: Factory-calibrated settings between 100 bar and 420 bar based on secondary load thresholds

• Internal Valve Core Topology: Pilot-operated poppet-type pressure relief mechanism integrated with a high-capacity anti-cavitation check bypass

• Maximum Sealed Internal Leakage: Kept under 15 drops per minute (less than 1 cc/min) at a continuous high-load pressure of 350 bar

• Base Metallurgy & Net Weight: Specialized heavy-duty carbon-vacuum tempered alloy steel shell; Weight varies from ~290g (VMR2) up to ~580g (VMR3)

Key Technical Advantages:

• Dual-Action Integrated Pressure Safeguard & Vacuum Protection: This single cartridge combines a rapid-response pilot relief valve with a high-capacity anti-cavitation check valve. When high-inertia equipment undergoes rapid braking, the valve quickly dumps damaging 420 bar spikes. If an inertial overrun creates a vacuum state in the motor, the check mechanism immediately shifts open to draw makeup fluid from the return line, completely preventing cavitation-induced pitting.

• Hardened Poppet-to-Seat Spherical Lapping Metallurgy: The core internal sliding pilot poppet and secondary check seats are sculpted from ultra-pure tool steel, subjected to rigorous multi-stage vacuum oil quenching to register an outer hardness exceeding HRC 62. Advanced spherical micro-lapping technologies form a mirror-finish boundary zone, ensuring minimal internal fluid leakage at 420 bar while eliminating pressure setting drift over long duty cycles.

• Two-Stage Damped Pressure Drops for Anti-Shock Shifting: The valve incorporates precision internal fluid orifices coupled with a multi-tiered stepped damping piston. When the valve triggers under sudden peak pressure overloads, fluid passes through successive stages of mechanical throttling. This dampens the abrupt hydraulic shock wave, preventing destructive fluid hammering and pipeline vibration.

• Heavy-Wall High-Tensile Shell with Anti-Erosion Coating: The outer cage and installation hex profile are CNC-milled from premium low-alloy solid steel bars. The wall thickness is optimized via Finite Element Analysis (FEA) to endure extreme axial pre-loads during assembly. All external steel surfaces receive rust-resistant phosphating or zinc-plating treatments, offering robust defense against abrasive debris and aggressive environments.

Application Areas:

• Hydrostatic Mobile Traction Circuits: Track drive configurations for heavy excavators and dual-speed closed-loop travel systems on crawling machinery.

• Heavy Lifting & Winching Assemblies: Secondary port-plate overload protection for main and auxiliary winch motors (A2FE107/A2FE180) on crawler cranes and all-terrain mobile cranes.

• Foundation & Foundation Drilling Platforms: Rotary drive motor loops for rotary drilling rigs and heavy-duty diaphragm wall grabs.

Expert Maintenance Tips:

• Rigidly Observe Torque Specifications with Calibrated Wrenches: Because these cartridges use thin-walled cages and close internal tolerances, over-torquing can cause catastrophic failure. For VMR2 (M30 threads), torque exactly to 130 – 140 N·m; for VMR3 (M36 threads), torque exactly to 180 – 190 N·m. Over-tightening will deform the cage, binding the pilot piston and preventing the valve from opening (risking system rupture) or sticking it open (causing severe power loss).

• Verify Fluorocarbon (FKM) O-Ring Integrity and Pre-Lubricate Prior to Insertion: High-pressure variants like R930054929 come equipped with premium FKM seals. Before threading the valve into the motor port plate, inspect all O-rings and backup rings for twists or micro-cuts, and apply a thin layer of clean hydraulic oil to ensure smooth seating without seal tearing.

• Enforce Strict Fluid Contamination Barriers to Protect Pilot Orifices: As the safety buffer for dynamic motor braking, this valve is highly vulnerable to wear debris (such as fine metal particles from the motor). Keep the main loop fluid cleanliness at ISO 4406 18/16/13 or better with premium inline glass-fiber elements ($\beta_{10} \ge 100$). Maintain oil temperatures below 65°C to prevent localized shear heat from degrading the elastomer seals.