Quick-closing valve part number 1956314001 195-63-14001 is a spare part for bulldozer SD32.

Quick-descent valve part number 1956314001 (195-63-14001) is a spare part for bulldozer SD32.

The quick-descent valve is a key control valve in the hydraulic system of a bulldozer's working device. Its core function is to enable the rapid descent of the bulldozer blade (blade) to improve work efficiency and maneuverability.

1. Core Functions and Roles

Rapid Descent: When the operator pushes the blade control lever to the "Descent" position, the quick-descent valve is activated. It allows the hydraulic fluid in the large chamber of the hydraulic cylinder (piston rod extension side) to flow directly and quickly back to the hydraulic tank through a larger channel or bypass, bypassing the precise flow through the main control valve.

Eliminating Back Pressure: In normal descent mode, the hydraulic fluid in the large chamber of the cylinder needs to return to the tank through the throttle orifice of the main control valve, which creates back pressure and slows down the blade descent. The quick-descent valve bypasses this resistance.

Improved Efficiency: Significantly reduces the time required for the blade to descend from the raised position to the ground or pile material, especially useful when leveling, pushing loose materials, or requiring rapid blade position adjustments.

Gravity Assist: Quick descent essentially utilizes the blade's own weight. The quick descent valve simply creates conditions for rapid hydraulic return, allowing gravity to function more effectively.

2. Working Position and Triggering

Typically Integrated into the Main Control Valve: The quick descent valve is not a completely separate valve block, but rather integrated into the blade control valve plate of the bulldozer's main control valve (multi-way valve).

Lever Travel Triggering: The quick descent valve is triggered when the operator pushes the blade control lever to the end of its "descent" stroke (usually beyond the normal descent position, with a noticeable "overtravel" feeling or area).

Mechanical or Hydraulic Linkage: Triggering may be achieved by directly pushing the quick descent valve spool through a mechanical push rod at the end of the control lever, or by moving the valve spool through a pilot hydraulic circuit.