Characteristics of double gear oil pump

Compared with the single gear pump, the double gear pump has two oil suction ports and two oil discharge ports, the rotor rotates once, and the oil is sucked and pressed twice. The pressure pulsation is small, and the radial forces acting on the stator, rotor and bearing are balanced. Inspired by this, combined with the characteristics of synchronous belt and harmonic gear transmission, we conceived a double-acting gear pump. Its main components include: internal gear, roller, pinion, sealing block, side plate, pump body and so on.

The pinion is a rigid external gear (the same as the existing gear pump, similar to the rigid gear in harmonic gear transmission), and the internal gear ring is a thin-walled gear ring that can withstand greater elastic deformation (equivalent to the flexspline in harmonic gear transmission), which is the same as the pinion in pitch and tooth width, but different in number of teeth. The inner gear ring and the pinion are meshed with each other and can rotate freely in the sealed pump body, and their rotation center lines are consistent.

There are two crescent-shaped sealing blocks (as shown in the figure) between the circular arc surface of the tooth top of the inner gear ring of the double gear oil pump and the tooth top circle of the pinion; Two side plates are arranged on both sides of the inner gear and the pinion in the width direction: the two gears are closely matched with the sealing block and the side plate, and the sealing space between the pinion and the inner gear ring is divided into four parts, namely, two symmetrical low-pressure oil suction chambers X and two symmetrical high-pressure oil discharge chambers P, so that the radial hydraulic pressure on the transmission shaft is equal in magnitude and opposite in direction.

Two axial oil suction holes (corresponding to the low-pressure chamber X) and two axial oil discharge holes (corresponding to the high-pressure chamber P) are opened on both sides of the plate and are arranged on the end cover of the plate. The oil inlet and outlet of that double pump are respectively communicate with the oil suction pipe and the oil discharge pipe outside the pump body.

The characteristic of double gear oil pump is that the cross section of inner teeth before deformation is round, and the diameter of outer wall circle is slightly larger than the distance between the inner sides of two rollers. When the internal gear ring is installed between two rollers, the cross section of the internal gear ring becomes elliptical due to the constraints of the rollers. The gear teeth near the two ends of the elliptical short shaft are fully meshed with the pinion teeth, while the gear teeth near the two ends of the long shaft are not meshed with the pinion; When the drive shaft drives the pinion to rotate, the internal gear ring rotates, and the meshing state between the gear ring and the pinion is constantly changing.