22 DISCO 9300C - 8600C with push operation 09 Hydraulic system main group 38342
Description of function Oil supply
Working position (mowing), without tractor mode.
in the working position
Lifting of all mower units from the working position to headland height (the tractor mode is active)
In the working position (mowing):
In parallel with the oil supply via port P1, oil supply via port P2 can be used for working operation of the mower units (raise, lower, mowing).
When actuating with the control terminal, oil supply is via P1. When actuating with the additional control unit of the tractor, oil supply is via P2.
When mowing, the mower units can be lifted on the headland using P1 and P2 as appropriate. When the operator decides in favour of the "Tractor“ mode, oil supply is via port P2. This offers the advantage that on the headland, the mower units are controlled with the ergonomically optimised control lever of the additional control unit of the tractor.
Now the additional control unit of the tractor is switched so that hydraulic oil is supplied through port (P2).
Oil supply via port P1 is used for:
The hydraulic oil flows through the solenoid valves and into the piston top spaces of the hydraulic cylinders (3148, 3132, 3133). All mower units are raised.
raising all mower units, the working position (mowing) of all mower units, the transport position of all mower units, the individual lift of the mower units, the load relief adjustment.
The pressure sensor (B278) detects the rising pressure. At around 40bar (~750mV) the electronic system integrates the signals from the angular sensors (position of mower units) into the control action. Raising beyond the headland height is not possible in order to protect the drive shafts of the mower units.
In mixed operation (oil supply through ports P1 and P2): – the P1 oil supply is used for individual lifting, – the mower units are controlled by the additional control unit of the tractor (P2) (raising to headland height and lowering to working position).
At an angular sensor signal of 1.2 – 1.7 V, the headland height has been reached.
Connection (T) must always be connected with the free return line of the tractor to achieve a sufficient drop rate of the mower units.
The range of 1.2 – 1.7 V results from the individual setting of the headland height. The headland height can be set within uncritical limits in order to protect the drive shafts of the mower units.
The oil quantity introduced through port P1 should be as small as possible (around 40 l/min) so that the return line still can accept enough oil for lowering the mower units.
Upon reaching the headland height, the solenoid valves (Y412, Y413 and Y415) are not energised any more (closed position) – the raise process is complete.
When the tractor mode is not activated (oil supply through P1), the solenoid valves (Y288, Y410, Y411, Y412, Y413, Y414, Y415) are energised in the working position (mowing).
The front mower unit which has no angular sensor is raised up to the limit stop for 5 seconds above the pressure threshold of around 40 bar. The solenoid valve (Y416) is now de-energised and closes.
When the tractor mode is activated, the solenoid valves (Y288, Y410 and Y411) are not energised. Solenoid valve (Y416) is energised. The signal from the pressure sensor (B278) is a precondition for the "Tractor mode“ function. The speed sensors (B198, B201, B202) detect the drive speeds of the mower units. As soon as a speed signal is available, raising beyond the headland height is not allowed any more in order to protect the drive shafts of the mower units.
00 0290 120 0 - SYS DISCO - 09/08
The limit positions of the mower units must be learned (angular sensors).
When the oil supply is through the additional control unit of the tractor (port P2), a minimum oil quantity of 40l/min is recommended to achieve satisfactory lift speeds.
Now the connection of the hydraulic cylinders through port T to the tractor tank is open.
Speed sensors
– the additional control unit of the tractor is in the "Float position“. Port P2 is connected with the tank of the tractor. – the tractor mode is selected on the control terminal. – In this process, the solenoid valves (Y288, Y410 and Y411) are not energised, solenoid valve (Y416) is energised (open passage to P2) and solenoid valves (Y412, Y413, Y414, Y415) are energised (open passage).
Individual lifting is by pressing a pushbutton on the control terminal. Oil supply here is via port P1.
– – – – –
Tractor mode
– the hydraulic oil flows in the neutral circulation from (P1) through the pump shut-off valve (7172), the tank shut-off valve (7173) and port (T) into the tank (free return line) of the tractor;. – the solenoids (Y288, Y410, Y412, Y414, Y411, Y413, Y415) are energised (open passage). The hydraulic cylinders (3148, 3132, 3133) are connected with the tractor tank through port T.
Lowering of mower units from the headland height to working position (tractor mode is active)
When the headland height has been reached, the additional control unit of the tractor is set to the neutral position. The pressure is enclosed between the solenoid valves (Y412, Y413, Y416) and port P2. For lowering to working position (mowing), the additional control unit of the tractor is set to the "Float position“. Now the pressure sensor (B278) detects the falling pressure. At around 28bar (~550mV), the electronics energise the solenoid valves (Y412, Y413, Y415 and Y416). These are opened so that the hydraulic cylinders (3148, 3132, 3133) are connected with the tractor tank via port P2 – the mower units are lowered.
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