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| Illustration 1 | g00934525 |
Saw Pump and Saw Motor Valve (1) On/off solenoid valve. (2) Saw motor valve. (3) Load sensing valve. (4) Compensator valve. (5) Saw pump. | |
The saw pump is mounted on the pump drive that is attached to the engine. The shaft of the pump is driven by the pump drive. The saw pump supplies the pressure oil to the saw motor.
The saw pump is a variable displacement axial piston pump. The pump flow is regulated by the load sensing control.
The saw pump supplies hydraulic oil to the saw motor valve and the saw motor.
Oil enters the saw pump from the hydraulic oil tank through inlet line (E). Case drain oil exits the pump through port (D). The case drain oil cools the pump. The case drain oil also lubricates the pump. Also, the case drain oil removes debris from the pump. The case drain oil is filtered by a case drain filter before flowing back to the hydraulic oil tank.
Pressure oil flows from the saw pump through line (B). The oil flows to the saw motor.
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| Illustration 2 | g00861934 |
(1) On/off solenoid valve. (2) Saw motor valve. (3) Load sensing valve. (4) Compensator valve. (5) Saw pump. (6) Valve. (7) Orifice. (8) Orifice. (9) Valve. (10) Pressure sensor (saw pump). (11) Orifice. (12) Orifice. (13) Servo piston. (14) Swashplate. (A) Return oil line. (B) Pressure line to saw motor. (C) Inlet line from tank. (D) Case drain line. (AA) Pressure tap (discharge pressure). | |
When the switch for the saw is not activated, pressure from saw pump (5) enters saw motor valve (2). Valve (6) shifts to the right. The oil from the saw pump flows through valve (6), the hydraulic oil cooler and the return filters. Then, the oil flows to the hydraulic tank.
When the engine is running and no functions are being used, a low pressure standby condition exists. The saw pump upstrokes to full stroke at low pressure when the switch for the saw is not activated. This causes the oil to return through the oil cooler and the return filters.
When the switch for the saw is activated, an electrical signal energizes on/off solenoid valve (1). On/off solenoid valve (1) shifts to the left. Pressure from saw pump (5) enters saw motor valve (2). Valve (9) shifts upward. The oil from the saw pump flows through valve (9) to the saw motor.
The pressure is approximately equal at both ends of load sensing valve (3). The spring in load sensing valve (3) keeps load sensing valve (3) shifted to the left.
Saw pump (5) remains at the maximum displacement position until you reach a maximum system pressure of compensator valve (4). The pressure setting of compensator valve (4) is 27400 kPa (3975 psi). At this point, the pump will destroke. Servo piston (13) continues to destroke the pump until swashplate (14) is at the minimum angle.
When the output pressure exceeds the setting of compensator valve (4), the compensator valve moves to the right. Oil flows through the compensator valve to the servo piston. The servo piston strokes the pump to a lower output.
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| Illustration 3 | g00861922 |
(3) Load sensing valve (4) Compensator valve (13) Servo piston (14) Swashplate (15) Ball seat (16) Piston with piston shoe (17) Volume control (18) Bearings (19) Saddle bearing (20) Retainer (21) Valve plate (B) Pressure outlet (C) Load sensing line (E) Inlet line | |