Flow Limit Valves
Show/hide table
|
|
|
| Illustration 1 | g03621658 |
Flow limit valves located in pump compartment (typical example)
|
Show/hide table
|
|
|
| Illustration 2 | g03621878 |
Flow limit valves located on top of main control valve (typical example)
|
Show/hide table
|
|
|
| Illustration 3 | g02304193 |
Valve cutaway, hydraulic schematic symbol, and electrical connector designation
|
Show/hide table
Table 1
| Current Range |
0 mA ~ 700 mA |
| Coil Resistance |
11.5 ± 0.5Ω (T=20° C) |
Show/hide table
|
|
|
| Illustration 4 | g02263554 |
A - Port pressure (kPa) vs Current (mA)
|
The machine ECM controls flow limitation pressure which is decided by throttle dial position, engine speed, and pump pressure through this solenoid.
The tool control system calculates the negative flow control pressure equivalent to the flow when the work tool is used at the set work tool parameters. The proportional reducing valve then sends out pressured oil for flow control of drive pump and idler pump.
Attachment Valves
Show/hide table
|
|
|
| Illustration 5 | g03620996 |
Attachment valves (A1 and A2) located in pump compartment (typical example)
|
Show/hide table
|
|
|
| Illustration 6 | g03623120 |
Attachment valves (A3) located in swing motor compartment (typical example)
|
Show/hide table
|
|
|
| Illustration 7 | g03623202 |
Attachment valves (A3) located in pump compartment (typical example)
|
Show/hide table
|
|
|
|
| Illustration 8 | g02304193 |
Valve cutaway, hydraulic schematic symbol, and electrical connector designation
|
Show/hide table
Table 2
| Current Range |
0 mA ~ 700 mA |
| Coil Resistance |
11.5 ± 0.5Ω (T=20° C) |
Show/hide table
|
|
|
|
| Illustration 9 | g02263554 |
A - Port pressure (kPa) vs Current (mA)
|
The proportional reducing valves electronically control the spool shift pressure for the attachment control valves. These valves make available of control of attachment control valve by electric control input or hydraulic control input. Operation of the work tool is enhanced because the spool shift pressure is controlled in accordance with operator control input.
Boom DOWN / Stick IN Pressure Limit Valves
Show/hide table
|
|
|
| Illustration 10 | g03623318 |
Boom DOWN / Stick IN pressure limiting valves located beneath main control valve (typical example)
|
Show/hide table
|
|
|
| Illustration 11 | g02304374 |
Valve cutaway, hydraulic schematic symbol, and electrical connector designation
|
Show/hide table
Table 3
| Current Range |
0 mA ~ 700 mA |
| Coil Resistance |
11.5 ± 0.5Ω (T=20° C) |
Show/hide table
|
|
|
| Illustration 12 | g02304414 |
A - Port pressure (kPa) vs Current (mA)
|
The Boom DOWN and Stick IN pressure limiting valves are used on the Combined Function - Electric Control system.
These proportional reducing valves electronically control spool shift pressure of the boom DOWN and stick IN control valves. This operation will allow better operability of the work tool by decreasing the boom DOWN and stick IN speed that is caused by a heavy work tool.
Variable Relief Valves
Show/hide table
|
|
|
| Illustration 13 | g03668196 |
Variable relief valves located above the swing motor compartment (typical example)
|
Show/hide table
|
|
|
| Illustration 14 | g02304476 |
Solenoid valve, hydraulic schematic symbol, and electrical connector designation
|
Show/hide table
Table 4
| Max Flow Rate |
400 L/min |
| P-Port Pressure Range |
980 kPa to 37700 kPa |
| Current Range |
0 mA ~ 1500 mA |
| Coil Resistance |
6.4 Ω (T=20° C) |
Show/hide table
|
|
|
| Illustration 15 | g03354830 |
P - Port pressure (kPa) vs Current (mA)
|
The proportional solenoid valve for variable relief is controlled directly by the machine ECM. When the ECM determines the requirements for relief pressure to the work tool, the ECM sends varying signals to the solenoids. Two of these solenoids are used to control relief pressure to the work tool for both one-way flow and two-way flow. The variable relief valves are used to control the oil flow sending oil to the return system for one-way flow.
