What is the drive mechanism of Rexroth gear pumps?

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The Rexroth gear pump is driven by a separate motor, which effectively prevents pressure fluctuations and flow variations upstream. The pressure fluctuation at the outlet of the Rexroth gear pump can be kept within 1%. Using a Rexroth gear pump on the extrusion line can increase the flow rate and output speed, while reducing the shear and residence time of the material inside the extruder. The Rexroth external gear pump is the most widely used type of gear pump; generally, when referring to a gear pump, it is the external gear pump that is meant. It mainly consists of a driving gear, a driven gear, a pump body, a pump cover, and a safety valve. The sealed space formed by the pump body, pump cover, and gears is the working chamber of the gear pump. The shafts of the two gears are mounted in the bearing holes on the two pump covers, respectively; the shaft of the driving gear extends out of the pump body and is rotated by an electric motor. External gear pumps feature a simple structure, light weight, low cost, reliable operation, and a wide range of applications. When a Rexroth gear pump is in operation, the driving wheel rotates together with the motor, causing the driven wheel to rotate as well. As the meshing teeth on the side of the suction chamber gradually separate, the volume of the suction chamber increases and the pressure decreases, which draws the liquid in the suction tube into the pump ； The inhaled liquid is divided into two streams and pushed into the discharge chamber by gears within the toothed groove. After the liquid enters the discharge chamber, the continuous meshing of the teeth of the two gears compresses the liquid, forcing it to flow from the discharge chamber into the discharge pipe. As the driving gear and the driven gear keep rotating, the pump can continuously draw in and discharge liquid. The Rexroth pump body is equipped with a safety valve; when the discharge pressure exceeds the specified value, the liquid being transported can automatically push open the safety valve, allowing the high-pressure liquid to flow back into the suction pipe. The Rexroth internal gear pump consists of a pair of intermeshing internal gears, a crescent-shaped element located between them, a pump casing, and other components. The crescent-shaped component serves to separate the suction chamber from the discharge chamber. As the driving gear rotates, a local vacuum is created where the gears are out of contact; liquid is drawn into the pump and fills the spaces between the teeth in the suction chamber, before then flowing into the discharge chamber in two streams along the inner and outer sides of the crescent-shaped component. At the point where the tooth teeth come into contact, the liquid present between them is squeezed and sent into the discharge pipe. In addition to having self-priming capabilities and a flow rate that is independent of the discharge pressure, Rexroth gear pumps lack suction and discharge valves in their pump casing. They feature a simple structure, uniform flow rate, and reliable operation. However, they have low efficiency, generate significant noise and vibration, and are prone to wear. They are used for transporting various oils that are non-corrosive, free of solid particles, and possess lubricating properties, with temperatures generally not exceeding 70 °C; examples include lubricating oils and edible vegetable oils. The typical flow rate ranges from 0.045 to 30 ms/h, the pressure range is from 0.7 to 20 MPa, and the operating speed is between 1200 and 4000 r/min.