The main pump generally includes a rotating assembly, a swash plate assembly and a valve block assembly. The rotating component is used to rotate and assume the main function of the entire pump. The swash plate component changes the output flow, and the valve block can separate the oil suction and the oil discharge.
(1) Rotating assembly
As shown in Figure 1-6, the rotating assembly includes the transmission shaft (front), cylinder body, plunger shoe, fixing plate, spherical bearing, washer and cylinder spring. The drive shaft is supported by bearings at both ends. The sliding shoe is embedded in the plunger to form a spherical coupling. It has a recessed hole to release the thrust created by the load pressure and keep the hydraulic pressure balanced, so that the sliding shoe can gently slide on the skateboard.
The branch assembly includes a plunger and a sliding shoe. The cylinder spring passes the retainer and the spherical bearing to make the sliding shoe press against the sliding plate.
Similarly, the cylinder body is pressed against the valve plate by the action of the cylinder spring.
(2) Swash plate assembly
As shown in Figure 1-7, the swash plate assembly includes a swash plate, a slide plate, a swash plate support frame, a tilt bearing, a tilt pin, and a servo plunger.
The swash plate is a cylindrical slidable part, corresponding to the sliding surface of the sliding shoe, and supported by the swash plate support frame.
When the hydraulic oil controlled by the regulator flows to the working chambers located at both ends of the servo plunger, the servo plunger will move to the right or left. The power of the servo plunger acting on the tilt pin causes the swash plate to slide on the support frame, changing the tilt angle (a).
(3) valve block
is shown in Figure 1-8. The valve assembly includes a valve block, a valve plate and a valve plate pin.
The valve plate is connected to the valve block. It has two half-moon shaped gates-oil supply port and oil suction port.
The hydraulic oil discharged through the valve plate is connected to an external oil pipe line through the valve block.
The drive shaft is driven by the engine, and the drive shaft will be connected to the cylinder body by splines at the same time. If the swash plate is tilted, the plunger in the cylinder will reciprocate relative to the cylinder and rotate with the cylinder.
A single plunger will move 180°, leave the valve plate (oil absorption process), and then do the remaining 180° movement toward the valve
(Draining process), at this time, the cylinder body rotates. When the inclination angle of the swash plate is 0°, the plunger is not stroked or discharged without oil.
