Engineering mining machinery accessories cartridge balancing valve CBEA-LAN

The pressure of relief valve rises but does not rise to the highest reason analysis

The pressure of the relief valve rises but does not rise to the highest adjusting pressure. This phenomenon is shown as follows: although the pressure regulating hand wheel is fully tightened, the pressure can not continue to rise after only rising to a certain value, especially when the oil temperature is high. The main reasons are as follows.

(1) The hydraulic oil temperature is high, and the internal leakage increases.

(2) The internal parts of the hydraulic pump wear, internal leakage increases, and the output flow decreases; The pressure increases, the output flow is smaller, the need for high load on the flow cannot be maintained, and the pressure rises less than the maximum pressure. And the performance is that after adjusting to the pressure, the pressure gauge pointer fluctuates sharply, the fluctuation range is large, and the relief valve pressure can not be adjusted up.

(3) Large dirt particles enter the main spool damping hole or bypass hole, and partially block the small hole, so that the pilot flow into the pilot valve is reduced, and it is difficult to establish a high pressure in the upper chamber of the main spool to balance the pressure in the lower chamber of the main spool, so that the pressure cannot rise to the highest.

(4) Because the main valve core is too loose with the valve body hole, it is strained, grooved, or seriously worn after use, a part of the oil flow entering the spring chamber through the main valve damping hole flows back to the oil port through this gap (such as Y-type valve, two-section concentric valve); For three-section concentric valves such as YF type, due to the wear of the sliding joint surface of the main valve spool and the valve cover matching hole, the matching gap is large, and the flow into the spring chamber through the main valve damping hole returns to the fuel tank through the gap.