Swing Parking Brake Solenoid Valve
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| Illustration 1 | g00936546 |
(1) Solenoid valve for swing parking brake (2) Passage from hydraulic activation control selector valve (3) Passage (4) Drain passage (5) Passage to swing parking brake (6) Passage (7) Passage for high pressure pilot supply (8) Passage (9) Solenoid valve for two-speed travel | |
Swing parking brake solenoid valve (1) controls pilot oil flow to the swing parking brakes. During operation, swing parking brake solenoid valve (1) is nonenergized. A nonenergized swing parking brake solenoid valve (1) returns the pilot oil from passage (5) to the swing parking brakes to drain passage (4) to the hydraulic tank. The force of the spring for the swing parking brake applies the swing parking brake.
When the swing pilot valve is actuated, the swing pressure switch opens. This sends an electrical signal to the machine control module. When swing parking brake solenoid valve (1) is energized, pilot oil is supplied to passage (5) for the swing parking brakes. Pilot oil in passage (5) for the swing parking brake releases the swing parking brakes. The swing parking brakes are located on the swing drives.
Solenoid Valve for Dual Pressure
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| Illustration 2 | g00936547 |
(2) Passage from the hydraulic activation control selector valve (3) Passage (4) Drain passage (6) Passage (7) Passage for high pressure pilot supply (8) Passage (10) Solenoid valve for dual pressure (12) Passage to load sensing signal relief valve (13) Solenoid valve for travel parking brake | |
Dual pressure solenoid valve (10) controls pilot oil flow to the load sensing signal relief valve. Dual pressure solenoid valve (10) is normally nonenergized. A nonenergized dual pressure solenoid valve (10) returns the pilot oil from passage (12) to the load sensing signal relief valve to drain passage (4) to the hydraulic tank. When a travel pilot valve is actuated, the travel pressure switch closes. This sends an electrical signal to the machine control module.
If no implement pilot valves have been actuated, an electrical signal is sent from the machine control module which energizes dual pressure solenoid valve (10). When dual pressure solenoid valve (10) is energized, pilot oil pressure is supplied from passage (2) to passage (12) to the load sensing signal relief valve. Pilot oil in passage (12) resets the load sensing signal relief valve in order to regulate the main system pressure to a pressure of 35000 kPa (5080 psi).
If an implement pilot valve has been actuated, the machine control module will not energize the dual pressure solenoid valve.
Solenoid Valve for Two-Speed Travel
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| Illustration 3 | g00936548 |
(1) Solenoid valve for the swing parking brake (2) Passage from the hydraulic activation control selector valve (3) Passage (4) Drain passage (6) Passage (7) Passage for high pressure pilot supply (8) Passage (9) Solenoid valve for two-speed travel (14) Passage to high pressure check valve | |
Solenoid valve (9) for two-speed travel controls the high pressure pilot oil flow to solenoid valve (13) for the travel parking brake. During normal operation, solenoid valve (9) for two-speed travel is not energized. When solenoid valve (9) for two-speed travel is not energized, the high pressure pilot oil flow is blocked to solenoid valve (13) for the travel parking brake. Solenoid valve (9) for two-speed travel passes the high pressure pilot oil to drain passage (4).
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| Illustration 4 | g00936549 |
(4) Drain passage (6) Passage (7) Passage for high pressure pilot supply (8) Passage (15) Passage for low pressure pilot supply (16) Low pressure check valve (17) High pressure check valve | |
When solenoid valve (9) for two-speed travel is not energized, the low pressure pilot oil passes through low pressure check valve (16). The low pressure pilot oil closes high pressure check valve (17). The low pressure pilot oil flows to solenoid valve (13) for the travel parking brake.
When an electrical signal from the travel speed switch energizes solenoid valve (9) for two-speed travel, the passage through solenoid valve (9) to the drain passage (4) is closed. Now, the high pressure pilot oil is sent through solenoid valve (9) for two-speed travel to high pressure check valve (17). The high pressure pilot oil closes low pressure check valve (16) and the high pressure pilot oil passes to solenoid valve (13) for the travel parking brake.
Solenoid Valve for the Travel Parking Brake
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| Illustration 5 | g00936550 |
(2) Passage from the hydraulic activation control selector valve (3) Passage (4) Drain passage (6) Passage (7) Passage for high pressure pilot supply (8) Passage (10) Solenoid valve for dual pressure (13) Solenoid valve for travel parking brake (18) Passage to travel parking brakes and travel motors | |
Solenoid valve (13) for the travel parking brake controls pilot oil flow in order to release the travel parking brakes. The travel parking brakes are located on the final drives.
Travel Parking Brakes Engaged
When the travel pilot valve is not actuated, solenoid valve (13) for the travel parking brake is nonenergized. A nonenergized solenoid valve (13) returns the pilot oil from passage (18) to the travel parking brake to drain passage (4) for the hydraulic tank. The force of the travel brake spring is greater than the pilot pressure and the travel brake spring applies the travel parking brakes.
Travel Parking Brakes Disengaged
When the travel pilot valve is actuated, the travel pressure switch closes. This sends an electrical signal to the machine control module. When solenoid valve (13) for the travel parking brake is energized, pilot oil pressure is supplied from passage (7) to passage (18) to the travel parking brake. The pilot pressure oil in passage (18) releases the travel parking brakes and the pilot pressure oil sets the travel speed. If solenoid valve (9) for the two-speed travel is not energized, the pilot oil is at the low pressure setting and the travel motors remain at slow travel speed. If solenoid valve (9) for the two-speed travel is energized, high pressure pilot oil is supplied to the travel motors and the travel motors destroke to fast travel speed.