Rexroth R921812451 R921812450 Hydraulic Motor Device High Quality Motor Assembly

This high-precision heavy-duty hydraulic motor device assembly adopts Rexroth's classic high-pressure plunger motor architecture, with core part number R921812451, and is perfectly compatible with the alternative code R921812450. As an absolute core component for high-performance fluid power output and precise speed/torque regulation, this assembly is widely matched with mainstream heavy-duty hydraulic excavators and various heavy-duty industrial drive circuits. The product is based on first principles optimization of the inclined disc plunger high shear resistance flow channel and rotating components, seamlessly carrying alternating loads under frequent reversing and severe impact conditions, ensuring absolute certainty of propulsion power. The physical dimensions of the product packaging are approximately 510mm × 360mm × 380mm, with an overall net weight of approximately 78kg.

"Extreme cleaning and torque tightening: Before lifting and docking, the flange installation surface and axial mating spline must be kept absolutely clean and free of any foreign objects or rust. All high-strength fastening bolts must be tightened using a torque wrench, strictly following the torque standard for symmetrical and phased cross tightening, to prevent local stress concentration from causing slight deformation of the shell.

Forced oil injection (core avoidance pit): When connecting high-pressure oil pipes, they must be absolutely aligned and do not connect the wrong drain pipe (Case Drain). Before starting the engine, it is necessary to fill the top of the motor housing with clean hydraulic oil through the air release/oil injection port. Dry grinding is strictly prohibited to start, otherwise the internal rotating components will undergo irreversible physical erosion within 3 seconds of ignition.

Low pressure transition and exhaust: After the first ignition, keep the engine idling and running at low pressure for 10-15 minutes for circuit exhaust. Control the actuator to perform several slow and alternating micro movements, confirm that there are no bubbles or abnormal noises in the circuit, and that the thermodynamic state is stable before gradually applying normal operating loads"