LG936L Wheel Loader. Instruction - page 29
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valve, pilot valve, pressure select valve, lift arm cylinder, bucket cylinder, hydraulic pressure oil tank
and pipe attachments. D32 multi-way valve is a two unit valve. D32A multi-way valve is a three unit
valve. The bucket unit includes dumping, neutral and receiving bucket in three positions. The
lift-arms unit controls four actions including floating, lowering, neutral and lifting to utilize the work
control of loader working device. The third hydraulic function can be reserves.
The set pressure of the safety valve is 16MPa ~16.5MPa. The overload pressure of the rocker
cylinder’s large cavity is 18MPa
～
18.5MPa
while that of the small cavity is 12MPa.
1-Life Arm Cylinder 2-Multi-way Valve 3-Steering cylinder 4-Redirector 5-Priority Valve
6- Steering and Speed Changing Pump 7-Work Pump 8-Hydraulic Oil Tank
9-Oil Returning Filter 10- Bucket Cylinder
Figure 5-2 Mechanical and Manual Control Hydraulic System Diagram
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B1
A1
B2
A2
K
1-Work and Pilot Pump 2-Pressure Select Valve 3-Oil Tank 4-Hydraulic Oil Radiator
5- Steering and Speed Changing Pump 6-Oil Returning Filter 7-Priority Valve 8-Redirector
9- Steering Cylinder 10-Pilot Valve 11-Multi-way Valve 12-Lift Arm Cylinder
13-Bucket Cylinder 14-Pilot Filter
Figure 5-3 Two Units Valve Pilot Control Hydraulic System Diagram
1-Work and Pilot Pump 2- Oil Tank 3- Pressure Select Valve 4-Hydraulic Oil Radiator
5- Steering and speed changing pump 6-Oil returning filter 7-Priority valve 8-Redirector
9- Steering Cylinder 10-Pilot Filter 11-Pilot Valve 12-Multi-way Valve 13-Lift-arm Cylinder
14-Bucket Cylinder
Figure 5-4 Three Units Valve Pilot Control Hydraulic System Diagram
3 Brake System
Brake system is used when the machine decelerates, stops or for long-term parking on the level
ground or slight incline. The brake system of this machine is composed of a driving brake system and
parking brake system as shown in Figure 5-5,5-6.
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1-Parking Brake Air Chamber 2- Brake Magnetic Valve
3- Combination Valve of Oil Water Separator 4- Air Compressor 5- Air Tank
6- Air Brake Valve 7- Air Booster Pump
Figure 5-5 LG36L Single Brake Pedal Braking Diagram
1- Air Booster Pump 2-Shuttle Valve 3- Air Brake Valve 4- Air Tank
5- Combination Valve of Oil Water Separator 6- Air Compressor 7- Brake Magnetic Valve
8- Parking Brake Air Chamber
Figure 5-6 LG936L Double Brake Pedal Braking Diagram
3.1 Driving Brake System(Single Brake Pedal):
As shown in Figure 5-5, this system is the single line, air pushing oil four wheels caliper disk brake
system.
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When the brake pedal is stepped on during driving, the compressed air in air tank 5 flows through air
brake valve 6 into the air chamber of the air booster valve 7. The compressed air pushes the piston of
the booster pump to change the oil pressure (oil pressure is about 14MPa). Brake fluid pushes the
piston of the caliper disk brake and makes the friction disk contact the brake plate to achieve the
purpose of slowing and braking.
Release the brake pedal, and the compressed air of the booster pump drains from the brake valve to
the atmosphere and the brake is released.
3.2 Driving Brake System(Single Brake Pedal):
As shown in Figure 5-6, this system is the double brake pedals, air pushing oil four wheels caliper
disk brake system using two brake calipers for front and back to increase the safety of whole vehicle.
When the left brake pedal is stepped on during driving, the compressed air in air tank 4 flows through
air brake valve 3 and shuttle valve 2 into the air chamber of the air booster pump 1. The compressed
air pushes the piston of the booster pump to change the oil pressure (oil pressure is about 14MPa).
Brake fluid pushes the piston of the caliper disk brake and makes the friction disk contact with the
brake plate to achieve the purpose of slowing and braking. The air pressure is outputted at the same
time to cut off the power of gear box.
When the right brake pedal is stepped on during driving, the brake principle is the same as left brake
pedal, but the power of transmission box is not cut off.
Release the brake pedal, and the compressed air of the booster pump drains from the brake valve to the atmosphere
and the brake is released.
3.3 Parking Brake System
This system employs two different forms: the total hydraulic clamping disc braking system and the
total hydraulic pin steering system. During driving, when the pressure of air in brake system is in
normal level, rotate the operating button of brake electromagnetic valve slightly, the button will
bounce out automatically, and then the compress air in the air tank through the brake magnetic valve
to the parking brake air chamber to pull the plug away and release the brake. When stopping, press
the operating button of brake magnetic valve, the compress air in the parking brake air chamber
through the air draining port of brake magnetic valve to aerospace. Then the brake is pulled up under
the spring to arrive to brake. At the same time, send an electric signal to turn on the parking brake
indicator, by which to alarm the operator that the vehicle is in the braking condition.
When the system air pressure is lower than 0.4Mpa, the brake magnetic valve will cut off
automatically to control the compress air in the parking brake air chamber to drain into the aerospace
by hand, so that the emergency brake is utilized to protect the safety of vehicle and people.
