In the gear pump, a pair of gears engaged with the same number of gears are mounted inside the housing, both ends of the gear are sealed by the end cap so that the two gears are divided into left and right two sealed oil chambers , With a sealed working volume between each tooth. When the gear is rotated in the direction as shown in the figure, the gear tooth is disengaged from the right side to expose the tooth space so as to increase the volume of the cavity and form a vacuum in the office. The oil in the oil tank is sucked by the hydraulic pump under the action of atmospheric pressure Tube into the right chamber (suction chamber), complete the suction process. As the gears rotate, the teeth of each tooth gear into the left chamber from the right chamber. In the left chamber, the teeth enter into meshing, and the teeth of the teeth occupy the positions of the teeth of the other side. As a result, the volume is reduced and the oil in the interdental space is gradually squeezed out to increase the pressure in the left chamber, The port output, the completion of the pressure process, while the left chamber is the pump drain chamber. Two gears continue to rotate, the pump suction port and drain port will continuously absorb and drain the oil, the pump kept feeding the system. From the energy conversion point of view, the gear pump is the first system to complete the energy conversion device, that is, the motor output mechanical energy into hydraulic fluid. (A) gear pump flow 1. In theory, the volume of oil to the discharge chamber should be equal to the volume of work between teeth. 2. Qt per revolution should be the sum of the work volumes of all the two gears. 3. It can be assumed that the working volume between teeth is equal to the effective volume of teeth. 4. Qt per revolution 1) is the sum of the interdental working volume of one gear and the effective tooth volume of the tooth; 2) an annular volume of radial width 2 m (m is the modulus) swept approximately by the effective part of the tooth B) When using the pump Qt calculated above, the value should be multiplied by a small correction k. The average Qt is: Qt = K · D · 2m · B · n × 10-6 L / min where: D - the diameter of the indexing circle, in mm; m - modulus, mm; B - tooth width, mm ; N - speed, r / min; K - correction factor, generally 1.05 ~ 1.15. Medium and low pressure gear pump to make the flow formula Qt = 6.66zm2Bn • 10-6 n L / min (2-4) high pressure gear pump flow formula: Qt = 7zm2Bn • 10-6 L / min (2-5) (tris ) Increase the theoretical flow of the gear pump Increase the gear diameter, tooth width, speed n and reduce the number of teeth. n is too high will cause the gear teeth to inhale the cavity too short time n and increased diameter to increase the circumferential speed of the gear, increased centrifugal force 1. Increased suction difficulties, lower root hydraulic pressure p may precipitate gas, resulting in Q minus Small, causing vibration and noise, and even make the pump unable to work 2. Therefore, the maximum circumferential speed should be limited according to the viscosity of the oil, 1) the maximum circumferential speed does not exceed 5 ~ 6m / s, 2) the maximum speed is generally 3000r / min or so. Larger tooth width will increase the radial force, tooth surface contact line longer, not easy to maintain a good seal. Although reducing the number of teeth can make the interdental volume V increased and Q increases, but will make Q of non-uniformity increased.