Case Puma 165, 180, 195, 210 Tractor Service Manual

Table of Contents

• Introduction
• Distribution Systems
• Power Production
• Power Train
• Travelling
• Body and Structure
• Working Arm

Manual Extract: Load Sensing reversing valves

Load Sensing reversing valves
This valve is used in all remote valves, in the EPC control valve and between the trailer brake valve, the control valve of the front axle suspension and, if necessary, the side-mounted remote valves. It ensures that the unit with the highest demand for oil pressure applies pilot oil pressure to the Load Sensing valve of the CCLS variable displacement pump.

The components of the high pressure oil circuit are connected via Load Sensing lines with the hydraulic Load Sensing valve, which controls the capacity of the hydraulic pump.

If the trailer brake system, the remote valves, the hydraulic powerlift or the front axle suspension (where fitted) are operated, the Load Sensing valve of the variable displacement pump compares the pressure in the Load Sensing line of the components with the delivery pressure of the hydraulic pump.

If the pump pressure is less than the sum of the pressures of Load Sensing line and spring pressure on the oil flow regulator, the pump capacity is increased. As soon as the demand of the oil circuit is fulfilled, the pump pressure exceeds the sum of the pressures from Load Sensing line and spring pressure of the oil flow control valves. This pushes the control pin in the oil flow control valve to the right, whereby the pilot oil is fed to the control cylinder of the variable displacement pump swash plate, which reduces the pump stroke and thus adjusts the capacity to the demand of the oil circuit.