The Travel Motor On CIPI Undercarriage Arrangements Which Are Based On 325 Track Type Excavators
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| Illustration 1 | g00934830 |
Travel motor (1) Drive shaft (3) Piston (5) Swashplate (6) Ball guide (7) Retainer (7) Spacer (8) Spring (9) Barrel (10) Piston guide (11) Check valve (12) Check valve (13) Passage (14) Brake pilot valve (15) Port (16) Valve plate (17) Head (19) Piston (21) Slipper (22) Retainer (23) Piston (24) Friction plate (25) Separator plate (26) Passage (27) Passage (28) Brake piston (29) Spring (30) Port (31) Drain port (32) Port (33) Port (34) Spool (35) Spring (36) Displacement change valve | |
The travel motor can be divided into the following groups:
- The rotary group consists of barrel (9), drive shaft (1), pistons (23), slippers (21), retainer (22), ball guide (6), spacer (7), and spring (8) .
- The parking brake consists of springs (29), brake piston (28), friction plates (24), separator plates (25), piston guide (10), and brake pilot valve (14) .
- The displacement change valve consists of displacement change valve (36), check valves (11) and (12), pistons (3) and (17), and springs (2) and (18) .
Operation
The path of the oil depends on the travel direction. Pump oil flows into the travel motor through port (32) or through port (33). Then, the oil is forced outward through port (33) or through port (32). The case drain oil that has leaked from the sliding surfaces and from the clearances returns to the hydraulic tank through drain port (31) of head (17) .
Supply oil from the lower pump flows in the left travel motor through port (33) during forward travel. The oil from port (33) flows through passage (13) in head (17) to passage (27) of valve plate (16). The oil now flows through passage (26) of barrel (9). This forces piston (23) to the left.
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| Illustration 2 | g00934832 |
Motor Passages (View From the Side of Head (17) ) (26) Passage (barrel) (27) Passage (valve plate) (37) Passage (valve plate) | |
Slipper (21), which is coupled to the piston, slides on the surface of swashplate (5) from the top center to the bottom center. Slipper (21) also rotates with barrel (9). The oil that is forced outward by the pistons on the outlet side flows through passages (26) and (37) of valve plate (16) and out through port (32). The barrel turns counterclockwise.
Drive shaft (1) is splined to the barrel. The drive shaft and barrel rotate counterclockwise for forward travel.
During reverse travel, port (33) functions as an oil return port and port (32) functions as a supply port. The left travel motor rotates clockwise.
As the right travel motor is supplied upper pump oil through port (32), the right travel motor turns clockwise to forward travel. Pump oil through port (33) turns the motor counterclockwise for reverse travel.
Parking Brake
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| Illustration 3 | g00934878 |
Parking brake (partial view) (1) Brake pilot valve (2) Port (3) Drive shaft (4) Head (5) Passage (6) Spring (7) Body (8) Barrel (9) Friction plate (10) Separator plate (11) Piston guide (12) Piston chamber (13) Brake piston (14) Passage | |
As pump oil is supplied to the travel motor, the parking brake is released and the motor starts rotation. When pump oil is not being supplied to the motor, the motor stops rotation and the parking brake mechanically engages.
In the parking brake section of the travel motor, friction plates (9) are splined to barrel (8). Separator plates (10) are splined to body (7).
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| Illustration 4 | g00934880 |
Brake pilot valve (2) Port (5) Passage (15) Spring (16) Valve (17) Retainer (18) Orifice | |
When no pump oil is supplied to the travel motor, brake piston (13) is pushed to the left by the force of spring (6). The oil in piston chamber (12) now flows to passage (14). The oil now flows through passage (5), and through orifice (18) of valve (16) in brake pilot valve (1) to the travel motor case drain. Friction plates (9) which are connected to barrel (8) and separator plates (10) which are connected to body (7) are pushed into contact. This locks the barrel to the body, preventing rotation of the barrel and shaft (3) .
Orifice (18) restricts return oil flow from piston chamber (12). The restriction of the return oil flow delays the application of the parking brake. The parking is delayed in order to provide time for the machine to stop. This helps prevent earlier wear and/or damage.
Prior to the operation of the travel motor, a portion of the pressure oil flows to port (2). Valve (16) is opened. The oil then flows through passages (5) and (14) to piston chamber (12). Brake piston (13) moves to the right against the force of spring (6). The pressure oil which is holding plates (9) and (10) together is released. This allows barrel (8) and drive shaft (3) to turn.
Displacement Change Valve
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| Illustration 5 | g00934994 |
Speed Change Valve (1) Swashplate (2) Piston (3) Piston chamber (4) Passage (5) Piston (6) Piston chamber (8) Passage (9) Displacement change valve (10) Port (11) Passage (12) Port (13) Check valve (14) Check valve (15) Port (16) Drive shaft | |
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| Illustration 6 | g00934882 |
Displacement change operation (large displacement) (1) Swashplate (2) Piston (3) Piston chamber (4) Passage (5) Piston (6) Piston chamber (7) Passage (8) Displacement change valve (9) Port (10) Passage (11) Port (12) Check valve (13) Check valve (14) Port (16) Passage (17) Passage (18) Passage (19) Adapter (20) Spring (21) Spool (22) Passage | |
Large Displacement Change Operation
When the travel speed control switch is placed in the LOW SPEED MODE position, the travel speed solenoid valve is not energized. Pilot oil is not supplied to port (10) of displacement change valve (9). The force of spring (21) moves spool (22) to the left until the spool comes in contact with adapter (20) .
The pump oil from port (15) flows through check valve (14), passages (11), (23) and (8), and flows into piston chamber (6). Piston (5) moves up. Swashplate (1) rotates increasing the angle.
The oil in piston chamber (3) drains into the hydraulic tank through passages (4), (17), (18), and (19) .
The motor holds swashplate (1) in the maximum angle position.
Small Displacement Change Operation
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| Illustration 7 | g00934883 |
Displacement change operation (small displacement) (1) Swashplate (2) Piston (3) Piston chamber (4) Passage (5) Piston (6) Piston chamber (7) Passage (8) Displacement change valve (9) Port (10) Passage (11) Port (12) Check valve (13) Check valve (14) Port (18) Passage (20) Spring (21) Spool (22) Passage (23) Passage (24) Passage | |
When the travel speed control switch is placed in the HIGH SPEED MODE position, the travel speed solenoid valve is energized. If the pump delivery pressure is below a certain level, due to a smaller machine load, pilot oil flows to port (10) of displacement change valve (9). Pilot oil moves spool (22) to the right against the force of spring (21). Passage (23) closes and passage (25) opens.
The pump oil flows through passages (11), (25) and (4) into piston chamber (3). Piston (2) moves up. Swashplate (1) rotates decreasing the angle.
The oil in piston chamber (6) drains into the hydraulic tank through passages (8), (24), and (19) .
The motor holds swashplate (1) at the minimum angle position.
The Travel Motor On CIPI Undercariage Arrangements Which Are Based On 325B Track Type Excavators
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| Illustration 8 | g00585589 |
Travel motor (1) Drive shaft (2) Stopper (3) Piston (4) Swashplate (5) Slipper (6) Retainer (7) Barrel (8) Piston guide (9) Check valve (10) Check valve (11) Passage (12) Brake pilot valve (13) Port (14) Valve plate (15) Head (16) Stopper (17) Piston (18) Ball guide (19) Spacer (20) Spring (21) Piston (22) Friction plate (23) Separator plate (24) Passage (25) Passage (26) Spring (27) Brake piston (28) Port (29) Drain port (30) Port (31) Port (32) Spool (33) Spring (34) Displacement change valve | |
The travel motor can be divided into the following groups:
- The rotary group consists of barrel (7), drive shaft (1), pistons (21), slippers (5), retainer (6), ball guide (18), spacer (19), and spring (20) .
- The parking brake consists of springs (26), brake piston (27), friction plates (22), separator plates (23), piston guide (8), and brake pilot valve (12) .
- The displacement change valve consists of displacement change valve (34), check valves (9) and (10), and pistons (3) and (17) .
Operation
The path of the oil depends on the travel direction. Pump oil flows into the travel motor through port (30) or through port (31). Then, the oil is forced outward through port (31) or through port (30). The case drain oil that has leaked from the sliding surfaces and from the clearances returns to the hydraulic tank through drain port (29) of head (15) .
Supply oil from the lower pump flows in the left travel motor through port (31) during forward travel. The oil from port (31) flows through passage (11) in head (15) to passage (25) of valve plate (14). The oil now flows through passage (24) of barrel (7). This forces piston (21) to the left.
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| Illustration 9 | g00585089 |
Motor Passages (View From the Side of Head (15) ) (24) Passage (barrel) (25) Passage (valve plate) (35) Passage (valve plate) | |
Slipper (5), which is coupled to the piston, slides on the surface of swashplate (4) from the top center to the bottom center. Slipper (5) also rotates with barrel (7). The oil that is forced outward by the pistons on the outlet side flows through passages (24) and (35) of valve plate (14) and out through port (30). The barrel turns counterclockwise.
Drive shaft (1) is splined to the barrel. The drive shaft and barrel rotate counterclockwise for forward travel.
During reverse travel, port (30) functions as an oil return port and port (31) functions as a supply port. The left travel motor rotates clockwise.
As the right travel motor is supplied upper pump oil through port (30), the right travel motor turns clockwise to forward travel. Pump oil through port (31) turns the motor counterclockwise for reverse travel.
Parking Brake
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| Illustration 10 | g00585149 |
Parking brake (partial view) (1) Brake pilot valve (2) Port (3) Drive shaft (4) Head (5) Passage (6) Spring (7) Body (8) Barrel (9) Friction plate (10) Separator plate (11) Piston guide (12) Piston chamber (13) Brake piston (14) Passage | |
As pump oil is supplied to the travel motor, the parking brake is released and the motor starts rotation. When pump oil is not being supplied to the motor, the motor stops rotation and the parking brake mechanically engages.
In the parking brake section of the travel motor, friction plates (9) are splined to barrel (8). Separator plates (10) are splined to body (7).
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| Illustration 11 | g00585236 |
Brake pilot valve (2) Port (5) Passage (15) Spring (16) Valve (17) Retainer (18) Orifice | |
When no pump oil is supplied to the travel motor, brake piston (13) is pushed to the left by the force of spring (6). The oil in piston chamber (12) now flows to passage (14). The oil now flows through passage (5), and through orifice (18) of valve (16) in brake pilot valve (1) to the travel motor case drain. Friction plates (9) which are connected to barrel (8) and separator plates (10) which are connected to body (7) are pushed into contact. This locks the barrel to the body, preventing rotation of the barrel and shaft (3) .
Orifice (18) restricts return oil flow from piston chamber (12). The restriction of the return oil flow delays the application of the parking brake. The parking is delayed in order to provide time for the machine to stop. This helps prevent earlier wear and/or damage.
Prior to the operation of the travel motor, a portion of the pressure oil flows to port (2). Valve (16) is opened. The oil then flows through passages (5) and (14) to piston chamber (12). Brake piston (13) moves to the right against the force of spring (6). The pressure oil which is holding plates (9) and (10) together is released. This allows barrel (7) and drive shaft (3) to turn.
Displacement Change Valve
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| Illustration 12 | g00585282 |
Travel motor (partial view) (1) Swashplate (2) Piston (3) Piston chamber (4) Passage (5) Piston (6) Piston chamber (7) Passage (8) Displacement change valve (9) Port (10) Passage (11) Port (12) Check valve (13) Check valve (14) Port (15) Drive shaft | |
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| Illustration 13 | g00585307 |
Displacement change operation (large displacement) (1) Swashplate (2) Piston (3) Piston chamber (4) Passage (5) Piston (6) Piston chamber (7) Passage (8) Displacement change valve (9) Port (10) Passage (11) Port (12) Check valve (13) Check valve (14) Port (16) Passage (17) Passage (18) Passage (19) Adapter (20) Spring (21) Spool (22) Passage | |
Large Displacement Change Operation
When the travel speed control switch is placed in the LOW SPEED MODE position, the travel speed solenoid valve is not energized. Pilot oil is not supplied to port (9) of displacement change valve (8). The force of spring (20) moves spool (21) to the left until the spool comes in contact with adapter (19) .
The pump oil from port (14) flows through check valve (13), passages (10), (22) and (7), and flows into piston chamber (6). Piston (5) moves up. Swashplate (1) rotates increasing the angle.
The oil in piston chamber (3) drains into the hydraulic tank through passages (4), (16), (17), and (18) .
The motor holds swashplate (1) in the maximum angle position.
Small Displacement Change Operation
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| Illustration 14 | g00585315 |
Displacement change operation (small displacement) (1) Swashplate (2) Piston (3) Piston chamber (4) Passage (5) Piston (6) Piston chamber (7) Passage (8) Displacement change valve (9) Port (10) Passage (11) Port (12) Check valve (13) Check valve (14) Port (18) Passage (20) Spring (21) Spool (22) Passage (23) Passage (24) Passage | |
When the travel speed control switch is placed in the HIGH SPEED MODE position, the travel speed solenoid valve is energized. If the pump delivery pressure is below a certain level, due to a smaller machine load, pilot oil flows to port (9) of displacement change valve (8). Pilot oil moves spool (21) to the right against the force of spring (20). Passage (22) closes and passage (24) opens.
The pump oil flows through passages (10), (24) and (4) into piston chamber (3). Piston (2) moves up. Swashplate (1) rotates decreasing the angle.
The oil in piston chamber (6) drains into the hydraulic tank through passages (7), (23), and (18) .
The motor holds swashplate (1) at the minimum angle position.
The Travel Motor On CIPI Undercariage Arrangements Which Are Based On 325C Track Type Excavators
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| Illustration 15 | g00682968 |
Travel motor (1) Drive shaft (2) Stopper (3) Piston (4) Swashplate (5) Slipper (6) Retainer (7) Barrel (8) Piston guide (9) Check valve (10) Check valve (11) Passage (12) Brake pilot valve (13) Port (14) Valve plate (15) Head (16) Stopper (17) Piston (18) Guide (19) Spacer (20) Spring (21) Piston (22) Friction plate (23) Separator plate (24) Passage (25) Passage (26) Brake spring (27) Brake piston (28) Port (29) Drain port (30) Port (31) Port (32) Spool (33) Spring (34) Displacement change valve | |
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| Illustration 16 | g00766167 |
Travel motor (partial schematic) (3) Piston (4) Swashplate (9) Check valve (10) Check valve (12) Brake pilot valve (14) Valve plate (17) Piston (28) Port (29) Drain port (30) Port (31) Port (34) Displacement change valve | |
The travel motor can be divided into the following three groups:
- The rotary group consists of the following components: drive shaft (1), slippers (5), retainer (6), barrel (7), guide (18), spacer (19), spring (20) and piston (21) .
- The parking brake consists of the following components: piston guide (8), brake pilot valve (12), friction plates (22), separator plates (23), brake spring (26) and brake piston (27) .
- The displacement change valve consists of the following components: piston (3), check valve (9), check valve (10), piston (17) and displacement change valve (34) .
Operation
The flow of the oil delivery from the pump depends on the direction of travel. The oil delivery from the pump flows into the travel motor through port (30) or port (31). Pump oil is forced out of the travel motor through port (31) or (30) .
The case drain oil returns to the hydraulic tank through drain port (29) of head (15) .
The oil delivery from the left pump flows into the left travel motor through port (30) during forward travel. The oil from port (30) flows through passage (11) in head (15) and through passage (25) in valve plate (14). The oil then flows through passage (24) of barrel (7) and the oil forces pistons (21) to move to the left.
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| Illustration 17 | g00700542 |
Motor passage (side view from head) (A) Top center (B) Outlet side (low pressure) (C) Bottom center (D) Inlet side (high pressure) (24) Passage (barrel) (25) Passage (valve plate) (35) Passage (valve plate) | |
Slipper (5) is coupled to the piston. Slipper (5) and the piston slide on the surface of plate (4) from the top center to the bottom center. Slipper (5) and the piston rotate with barrel (7). Left pump supply oil flows through passage (25) of valve plate (14) into pistons (21). Oil is discharged through passage (11) of piston (21). The oil then flows through passage (35) of valve plate (14). The oil then flows through port (31). The barrel turns counterclockwise.
Drive shaft (1) is splined to barrel (7). The shaft and barrel of the left travel motor rotate counterclockwise for forward travel.
In reverse travel, port (30) functions as an oil return port. Port (31) functions as a supply port. The left travel motor rotates clockwise.
When the right travel motor receives the oil delivery from the right pump through port (30), the right travel motor turns clockwise for forward travel. When the oil delivery from the right pump flows through port (31), the right travel motor turns counterclockwise for reverse travel.
Travel Parking Brake
The travel parking brake is built into the travel motor. When the oil delivery from the pump flows to the travel motor, the parking brake releases and the travel motor starts rotating. When no oil delivery flows to the travel motor, the rotation of the travel motor stops and the travel parking brake engages. For more information concerning the operation of the travel motor, refer to Systems Operation, "Travel Motor".
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| Illustration 18 | g00827883 |
Parking brake (parking brake engaged) (1) Brake pilot valve (2) Port (3) Drive shaft (4) Head (5) Passage (6) Brake spring (7) Housing (8) Barrel (9) Friction plate (10) Separator plate (11) Piston guide (12) Piston chamber (13) Brake piston (14) Passage (15) Spring (16) Valve (17) Retainer (18) Orifice | |
In the parking brake section of the travel motor, separator plates (10) are splined to housing (7). Friction plates (9) are splined to barrel (8) .
When the travel lever/pedal is returned to the NEUTRAL position, the oil delivery from the pump is blocked at the travel control valve in the main control valve. Valve (16) moves to the right by the force of spring (15). The oil delivery from the pump does not flow through valve (16). The force of the oil pressure on the left side of brake piston (13) now becomes lower than the force of brake spring (6). The brake piston is pushed slowly to the left by the force of the brake spring. The oil in piston chamber (12) now flows through passage (14) and passage (5). The oil flows through orifice (18) and into the valve of the motor case drain line. Friction plates (9) and separator plates (10) are forced together by the force of brake spring (6). Friction plates (9) are splined to barrel (8). Separator plates (10) are splined to housing (7). When the separator plates and the friction plates are forced together, the rotation of drive shaft (3) in the travel motor gradually slows to a stop as the parking brake engages.
Orifice (18) restricts return oil flow from piston chamber (12). The restriction of the return oil flow delays the application of the parking brake. The parking brake is delayed in order to give the machine time to stop. Earlier wear and/or damage to the machine could result if the machine stayed in motion.
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| Illustration 19 | g00827909 |
Parking brake (brake released) (1) Brake pilot valve (2) Port (3) Drive shaft (4) Head (5) Passage (6) Brake spring (7) Housing (8) Barrel (9) Friction plate (10) Separator plate (11) Piston guide (12) Piston chamber (13) Brake piston (14) Passage (15) Spring (16) Valve (17) Retainer (18) Orifice | |
When a travel lever/pedal is moved from the NEUTRAL position, the oil delivery from the pump flows to the inlet port of the travel motor from the travel control valve in the main control valve. A portion of the oil delivery from the pump flows through port (2). Valve (16) moves to the left against the force of spring (15). The oil then flows through passages (5) and (14) to piston chamber (12). Brake piston (13) moves to the right against the force of brake spring (6). The spring force that is holding friction plates (9) and separator plates (10) together is released. Barrel (8) and drive shaft (3) start to rotate.
Displacement Change Valve
Small Displacement Change Operation
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| Illustration 20 | g00820789 |
Travel motor (partial diagram) (1) Swashplate (2) Piston (3) Piston chamber (4) Passage (5) Displacement change valve (6) Port (pilot system oil pressure) (7) Port (supply oil or return oil) (8) Check valve (9) Check valve (10) Port (supply oil or return oil) (11) Passage (12) Piston chamber (13) Piston | |
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| Illustration 21 | g00675199 |
Small displacement change operation (1) Swashplate (2) Piston (3) Piston chamber (4) Passage (return oil) (5) Displacement change valve (6) Port (pilot system oil pressure) (7) Port (supply oil or return oil) (8) Check valve (9) Check valve (10) Port (supply oil or return oil) (11) Passage (pump delivery flow) (12) Piston chamber (13) Piston (14) Spool (15) Spring (16) Body (17) Spool chamber (18) Spool chamber (19) Passage (return oil) (20) Hydraulic tank | |
When the travel speed control switch on the control panel is pushed and the rabbit appears on the display, the machine is in HIGH SPEED MODE. In this condition, an input signal from the travel speed control switch is sent to the engine and pump controller. The pressure sensor for the pump delivery also provides an input signal to the engine and pump controller. When the travel load is light and when the pump delivery pressure is below a certain level, the output signal from the pressure sensor for the pump delivery is below a certain level. When the pump delivery pressure is below a certain level, the engine and pump controller energizes the travel speed solenoid. When the travel speed solenoid is energized, pilot system oil flows into pilot port (6) of displacement change valve (5). Spool (14) moves to the right against the force of spring (15) until the spool contacts body (16). Main pump oil flows from passage (7) of the travel motor through check valve (8). The main pump oil then flows through spool chamber (17) and passage (11) to piston chamber (12). The oil in piston chamber (12) moves piston (13) against swashplate (1). Swashplate (1) forces piston (2) into piston chamber (3). The oil in piston chamber (3) flows through passage (4), spool chamber (18) and passage (19) to hydraulic tank (20). As a result, the angle of swashplate (1) is decreased and the motor displacement is decreased. The travel speed is maximum in this condition.
Large Displacement Change Operation
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| Illustration 22 | g00675334 |
Large displacement change operation (1) Swashplate (2) Piston (3) Piston chamber (4) Passage (return oil) (5) Displacement change valve (6) Port (pilot system oil pressure) (7) Port (supply oil or return oil) (8) Check valve (9) Check valve (10) Port (supply oil or return oil) (11) Passage (pump delivery flow) (12) Piston chamber (13) Piston (14) Spool (15) Spring (16) Body (17) Spool chamber (18) Spool chamber (19) Passage (return oil) (20) Hydraulic tank (21) Stopper (22) Center passage | |
When the angle of swashplate (1) in the travel motor increases, the displacement of the travel motor increases. The angle of swashplate (1) in the travel motor will increase and the travel speed will decrease during the following two conditions.
- The angle of swashplate (1) in the travel motor will increase and the travel speed will decrease when an increase in pump pressure occurs.
When the machine is in HIGH SPEED MODE and the pump delivery pressure increases above a certain level, the engine and pump controller de-energizes the travel speed solenoid. When the travel speed solenoid is de-energized, pilot system oil stops flowing into pilot port (6) of displacement change valve (5). Spool (14) moves to the left by the force of spring (15) until the spool contacts stopper (21). Main pump oil flows from port (7) of the travel motor through check valve (8). The main pump oil then flows through spool chamber (18) and passage (4) into piston chamber (3). The oil in piston chamber (3) moves piston (2) against swashplate (1). The angle of swashplate (1) increases. Swashplate (1) forces piston (13) into piston chamber (12). The oil in piston chamber (3) flows through passage (4), spool chamber (17) and center passage (22) of spool (14). The oil then flows through passage (19) to hydraulic tank (20). As the angle of swashplate (1) increases, the displacement of the travel motor increases and the travel speed decreases.
- The angle of swashplate (1) in the travel motor will increase and the travel speed will decrease when the travel speed control switch is pushed in order to obtain LOW SPEED MODE.
When the travel speed control switch on the control panel is pushed and the tortoise appears on the display, the machine is in LOW SPEED MODE. In this condition, an input signal from the travel speed control switch is sent to the engine and pump controller. The engine and pump controller de-energizes the travel speed solenoid. The angle of swashplate (1) increases and the displacement of the travel motor increases. The travel speed decreases.