Transmission hydraulic pump 16Y-75-24000 (16Y7524000) is a spare part for bulldozer SD16.

Transmission Hydraulic Pump 16Y-75-24000 (16Y7524000) is a spare part for bulldozer SD16.

The transmission hydraulic pump is a crucial, heart-like power component in the bulldozer's power transmission system. It plays a central role in the hydraulic-mechanical transmission or all-power shift transmission commonly used in modern tracked bulldozers.

1. Core Functions and Roles

Providing hydraulic power to the transmission control system: This is its primary task. It generates and outputs high-pressure hydraulic oil, driving the shift clutch/brake pistons within the transmission to achieve gear shifting (power shifting). Without this pressure, the transmission cannot shift gears.

Maintaining torque converter oil supply: The hydraulic torque converter requires a full oil supply to operate. The hydraulic pump provides oil to replenish losses within the torque converter caused by leakage and heat dissipation.

Providing cooling oil: The torque converter generates a large amount of heat during operation. The hydraulic pump supplies oil that flows through the torque converter, then enters the torque converter outlet pressure valve and cooler for heat dissipation, serving as the core driving force for the torque converter cooling cycle.

Establishing Control System Pressure: Provides the working pressure basis for transmission control valves (such as shift valves, pressure regulating valves, and torque converter outlet pressure valves), enabling them to precisely control the flow and pressure of the hydraulic fluid.

Driving Auxiliary Devices (Some Models): In some designs, the transmission pump may also provide a partial oil supply for the hydraulic control of the steering clutch or brakes (although there is usually an independent or prioritized steering system).

2. Types and Structures

External Gear Pumps: Simple in structure, robust and durable, relatively low in cost, and highly resistant to contamination, making them ideal for the harsh working environments of bulldozers and the extremely high reliability requirements of transmission systems. This is the most common type.

Internal Gear Pumps (such as cycloidal pumps): Lower noise and smaller flow pulsation, but may be slightly more expensive or have slightly lower pressure resistance than external gear pumps; they are also widely used.

Fixed displacement pumps are the primary type used in bulldozer transmissions: The vast majority of bulldozer transmission hydraulic pumps are fixed displacement pumps. Their displacement (the amount of oil output per revolution) is fixed, and the output flow rate is proportional to the engine speed. The system pressure is regulated by a pressure control valve (main pressure regulating valve), and flow distribution is controlled by shift valves, etc.