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| Illustration 1 | g00791575 |
The Illustration above shows the Auxiliary System when a Work Tool Cylinder is Operating. (1) Diverter valve (2) Coupler cylinder (quick coupler) (3) Load control valve for coupler cylinder (4) Bank valve (5) Signal relief valve (6) Line (load sensing) (7) Work tool cylinder (8) Rear section of stabilizer control valve (9) Front section of stabilizer control valve (10) Stabilizer control valve (11) Stabilizer cylinder (right side) (12) Stabilizer cylinder (left side) (13) Load control valve for left side stabilizer cylinder (14) Load control valve for right side stabilizer cylinder (15) End section of bank valve (16) Joystick (17) Implement section of bank valve (frame leveling) (18) Dual stage relief valve (19) Relief valve (coupler tilt) (20) Implement section of bank valve (boom extend/retract) (21) Pilot control valve (22) Solenoid valve (23) Solenoid valve (24) Solenoid valve (25) Solenoid valve (26) Pressure reducing valve (27) Brake reservoir (28) Hydraulic tank (29) Piston pump (30) Filter (31) Line (load sensing) (32) Inlet section of bank valve (33) Metering pump (34) Compensating cylinders (35) Valve (quick coupler pins) (36) Implement section of bank valve (boom raise/lower) (37) Load control valve for telescoping cylinder (38) Boom cylinder (boom raise/lower) (39) Implement section of bank valve (coupler tilt) (40) Load control valve for boom cylinder (41) Relief valve (coupler tilt) (42) Relief valve (43) Telescoping cylinder (boom extend/retract) (44) Implement section of bank valve (auxiliary section) (45) Valve (46) Load control valve for frame leveling cylinder (47) Frame leveling cylinder (48) Load control valve for tilt cylinder (49) Tilt cylinder (coupler tilt) (PP) Pump delivery (CP1) Work tool cylinder (pressure oil) (R) Return oil (S) Suction oil (LS) Load sensing oil (P) Pilot oil | |
The main components of the auxiliary system are implement section (44) of bank valve (4) and diverter valve (1). The diverter valve is equipped with two quick couplers in order to provide a connection to work tool cylinder (7).
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| Illustration 2 | g00791576 |
Joystick | |
Implement section (44) is operated by solenoids. The solenoids are controlled by switches on joystick (16) .
Control of implement section (44) is not proportional. When the switch on joystick (16) is operated, the spool is fully offset. This connects the service that is selected to piston pump (29) and to hydraulic tank (28). The output of the piston pump is controlled by the load pressure from work tool cylinder (7). Load pressure from the work tool cylinder is transmitted to the pump via the resolver network of bank valve (4) and load sensing line (31).
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| Illustration 3 | g00741690 |
Diverter Valve | |
Diverter valve (1) is located at the boom head. The diverter valve permits the operation of a work tool cylinder when the handle is in the upper position. The quick couplers that are located in the diverter valve provide a connection for the hydraulic lines from a work tool.
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| Illustration 4 | g00791625 |
Rolling Hoses | |
The diverter valve is connected to bank valve (4) by rolling hoses which are located inside the boom.
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| Illustration 5 | g00791577 |
Location of the Relief Valves in the Bank Valve (5) Signal relief valve (18) Dual stage relief valve (42) Relief valve (44) Implement section of bank valve (auxiliary section) (50) Port (quick coupler) (51) Port (dual stage relief valve) | |
Dual stage relief valve (18) and relief valve (42) control load pressure in the work ports of implement section (44). The dual stage relief valve and the relief valve are set at a lower pressure than signal relief valve (5) .
Relief Valve
The following section describes the operation of relief valve (42).
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| Illustration 6 | g00791579 |
Relief Valve (42) (52) Spring (53) Spring (54) Valve seat (55) Spring (56) Hole (57) Anticavitation piston (58) Service port (59) Piston (60) Tank return port (61) Orifice (62) Anticavitation chamber (63) Pilot valve | |
Pressure in service port (58) acts on the face of anticavitation piston (57). The same pressure acts on pilot valve (63) and at the rear of piston (59) by way of orifice (61) .
At the set pressure, pilot valve (63) is unseated. The pilot valve moves away from valve seat (54) against the force of spring (52). Pressure in anticavitation chamber (62) is relieved around the outside of anticavitation piston (57) to tank return port (60) .
Pressure that acts on the face of piston (59) unseats the piston and the piston moves away from the seat in anticavitation piston (57) against the force of spring (55). This allows pressure in service port (58) to be relieved through holes (56) in the anticavitation piston.
Makeup flow will occur if pressure in service port (58) falls below the pressure in tank return port (60). Anticavitation piston (57) is offset by pressure in the tank return port and spring (53) is compressed. Oil enters the service port from the tank return port. When the pressure in the service port is equal to the pressure in the tank return port, anticavitation piston (57) is reseated by spring (53) .
Dual Stage Relief Valve
The following section describes the operation of dual stage relief valve (18) in the first stage.
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| Illustration 7 | g00791581 |
Dual Stage Relief Valve (18) (51) Port (64) Piston (65) Hole (66) Spring (67) Pilot valve (68) Piston (69) Service port (70) Orifice (71) Piston (72) Tank return port (73) Chamber (74) Valve seat (75) Spring (76) Spring | |
Pressure in service port (69) acts on the face of piston (71). The same pressure acts on pilot valve (67) and at the rear of piston (64) by way of orifice (70) .
At the set pressure, pilot valve (67) is unseated. The pilot valve moves away from valve seat (74) against the force of spring (76). Pressure in chamber (73) is relieved around the outside of piston (71) to tank return port (72) .
Pressure that acts on the face of piston (64) unseats the piston. The piston moves away from the seat in piston (71) against the force of spring (66). This allows pressure in service port (69) to be relieved through holes (65) in piston (71) .
Makeup flow will occur if pressure in service port (69) falls below the pressure in tank return port (72). Piston (71) is offset by pressure in the tank return port and spring (75) is compressed. Oil enters the service port from the tank return port. When the pressure in the service port is equal to the pressure in the tank return port, piston (71) is reseated by spring (75) .
The following section describes the operation of dual stage relief valve (18) in the second stage.
The pressure setting of the dual stage relief valve is increased in order to disengage the quick coupler pins. The quick coupler switch on the instrument panel must be pressed in order to energize the solenoid for valve (35) in inlet section (32) .
Pump pressure is transmitted through port (50) in the inlet section to port (51) in dual stage relief valve (18). Piston (68) is offset against spring (76) by the increase in pressure. The increase in spring force increases the pressure setting of pilot valve (67) .