Piston Pump 420E, Backhoe Loaders Hydraulic and Steering System Cat

Piston Pump (Implement and Steering)... 420E, 430E, 432E, 434E, 442E a...1 de 21 AV Spare ∠ https://avspare.com/catalog/cat/content/i02440177/ [email protected] Create a motion Main » Autodata » Caterpillar Piston Pump (Implement and Steering)... 420E, 430E, 432E, 434E, 442E and 444E Backhoe Loaders Hydraulic and Steering System Caterpillar Usage: 432E BXE 430E DDT 430E EAT 434E FSH 442E GKZ 420E HLS 420E KMW 444E LBE 06/10/2016 11:53 a.m. Piston Pump (Implement and Steering)... 420E, 430E, 432E, 434E, 442E a... 2 de 21 Illustration 1 https://avspare.com/catalog/cat/content/i02440177/ g01281601 (1) Torque Control (2) Flow Compensator (3) Torque Limiter (4) Solenoid for Torque Control (5) Pump controller (6) Pump 06/10/2016 11:53 a.m. 420E. The piston pump (6) senses both pressure and flow needs. 3 de 21 https://avspare..Piston Pump (Implement and Steering). Margin pressure is the difference between the pressure that is needed at the work port and the supply pressure that is higher.com/catalog/cat/content/i02440177/ The piston pump (6) for the hydraulic system is controlled by the load signal from the implements..m.. The pump outlet pressure is maintained about 2150 kPa to 2450 kPa (312 psi to 355 psi) above the needed pressure of the work port by the flow compensator (2) . the single highest pressure in the system flows to flow compensator (2) . 06/10/2016 11:53 a. 432E. 434E. . If one or more circuits are being used. 430E.. The system pressure will be greater than the requirements for the highest work port pressure unless the pump is at full stroke. 442E a. The flow compensator (2) keeps the pump output at a level that is needed in order to fulfill the flow and pressure requirements of the system. The piston pump (6) also senses hydraulic power. 4 de 21 Illustration 2 https://avspare. The movement of the swashplate will cause the pump to upstroke or the movement will cause the pump to destroke. 430E. the pump (6) is at low pressure standby. Bias piston (7) and actuator piston (10) .. Flow compensator (2) and the torque control (1) change pump output by regulating the discharge pressure of the pump that is acting on actuator piston (10) .. 434E. 442E a.com/catalog/cat/content/i02440177/ g01293615 (1) Torque Control (2) Flow Compensator (3) Torque Limiter (5) Pump controller (6) Pump (7) Bias piston (8) Spring (9) Swashplate (10) Actuator piston (12) Piston (intake) (13) Piston (20) Pump output The pump has two actuators for control. .. The spring (8) in the small actuator (7) causes swashplate (9) to move. Actuator piston (10) has a larger area than the Bias piston (7) .. Low Pressure Standby 06/10/2016 11:53 a. 420E.m. 432E. When none of the hydraulic circuits are being used.Piston Pump (Implement and Steering). Actuator piston (10) causes the swashplate to destroke the pump. 442E a. 432E. 5 de 21 Illustration 3 https://avspare. . 430E.m..com/catalog/cat/content/i02440177/ g01281794 (1) Torque Control (1A) Spring (2) Flow Compensator (2A) Spring (3) Torque Limiter (4) Solenoid for Torque Control (5) Pump controller (6) Pump (7) Bias piston (8) Spring 06/10/2016 11:53 a..Piston Pump (Implement and Steering). 420E... 434E. 6 de 21 https://avspare. the spring setting is reduced. This oil flow creates a load sensing signal. With all the implements in the HOLD position. when the implement controls are in the HOLD position and the steering is inactive. which is sensed at the flow compensator (2) . 420E.m. . 434E. The swashplate (9) is at the minimum angle.. Refer to Illustration 3. 432E. The stop for the minimum angle (21) prevents the swashplate (9) from moving to a true minimum angle position.Piston Pump (Implement and Steering). the steering priority valve allows some supply oil to flow through a orifice. This applies the maximum setting on the spring in the torque limiter (3) . Then. This stop for the minimum angle is not adjustable. 430E. The spring setting of the torque limiter (3) changes with the swashplate angle. As the swashplate angle is increased...com/catalog/cat/content/i02440177/ (9) Swashplate (10) Actuator piston (12) Piston (intake) (13) Piston (14) Outlet manifold for the backhoe (15) Relief valve for the margin pressure (flushing valve) (16) Input for Load signal (17) Drain valve for the signal pressure (18) Relief valve for the signal pressure (19) Orifice (20) Pump output (21) Stop for Minimum angle The pump is at low pressure standby. The LOW PRESSURE STANDBY reading will be higher than margin pressure due to an internal stop for minimum angle (21) . the oil flows back to the tank through the metering pump. 442E a. This causes the margin relief (15) to open sending the pump flow to the tank through the outlet manifold for the backhoe (14) . Upstroke or Destroke 06/10/2016 11:53 a.. 434E. 7 de 21 Illustration 4 https://avspare.. 430E..Piston Pump (Implement and Steering).. 420E. . 442E a..com/catalog/cat/content/i02440177/ g01281782 (1) Torque Control (1A) Spring (2) Flow Compensator (2A) Spring (3) Torque Limiter (4) Solenoid for Torque Control (5) Pump controller (6) Pump (7) Bias piston (8) Spring 06/10/2016 11:53 a.m. 432E. The pump supply pressure moves the flow compensator (2) upward. 432E. 430E. 420E. When pump flow matches needs of the system.. Pump supply oil flows to the flow compensator (2) and the oil acts on the compensator spool. Constant Flow is maintained until there is a change in the requirements for system flow. The flow compensator spool (2) meters reduced pump supply oil to the actuator piston (10) in the pump case. 8 de 21 https://avspare. the pump supply pressure equals the sum of the system pressure plus the pressure of the spring (2A) .. .Piston Pump (Implement and Steering). The flow compensator is in a metering position and the system is stabilized. Supply oil also flows into a cross-drilled passage and an axial drilled passage in the flow compensator spool (2) . Metering 06/10/2016 11:53 a. 434E.com/catalog/cat/content/i02440177/ (9) Swashplate (10) Actuator piston (12) Piston (intake) (13) Piston (14) Outlet manifold for the backhoe (15) Relief valve for the margin pressure (flushing valve) (16) Input for the Load signal (17) Drain valve for the signal pressure (18) Relief valve for the signal pressure (19) Orifice (20) Pump output (21) Stop for the Minimum angle The pump will move to the UPSTROKE position or to the DESTROKE position in order to match changes in flow requirements. 442E a...m. This moves the swashplate (9) to an angle that satisfies the needs of the system. This opens a small passage between the spool and the body of the pump control valve. 420E. 430E.com/catalog/cat/content/i02440177/ g01281780 (1) Torque Control (1A) Spring (2) Flow Compensator (2A) Spring (3) Torque Limiter (4) Solenoid for Torque Control (5) Pump controller (6) Pump (7) Bias piston (8) Spring 06/10/2016 11:53 a..m. 434E... 442E a.Piston Pump (Implement and Steering).. 9 de 21 Illustration 5 https://avspare. . 432E. . 432E.Piston Pump (Implement and Steering). 442E a. 10 de 21 https://avspare. 430E.com/catalog/cat/content/i02440177/ (9) Swashplate (10) Actuator piston (12) Piston (intake) (13) Piston (14) Outlet manifold for the backhoe (15) Relief valve for the margin pressure (flushing valve) (16) Input for Load signal (17) Drain valve for the signal pressure (18) Relief valve for the signal pressure (19) Orifice (20) Pump output (21) Stop for the Minimum angle In the metering position. The pump will stay in the metering position until the flow requirements change.m. High Pressure Stall 06/10/2016 11:53 a.. The pump will maintain the flow that is required in order to maintain system pressure. . the signal pressure and the force of spring (2A) equals the pump supply pressure below the flow compensator spool (2) .. 420E. 434E.. 434E.. .... 442E a. 11 de 21 Illustration 6 https://avspare. 420E. 430E.m. 432E.com/catalog/cat/content/i02440177/ g01281727 (1) Torque Control (1A) Spring (2) Flow Compensator (2A) Spring (3) Torque Limiter (4) Solenoid for the Torque Control (5) Pump controller (6) Pump (7) Bias piston (8) Spring 06/10/2016 11:53 a.Piston Pump (Implement and Steering). com/catalog/cat/content/i02440177/ (9) Swashplate (10) Actuator piston (12) Piston (intake) (13) Piston (14) Outlet manifold for the backhoe (15) Relief valve for the margin pressure (flushing valve) (16) Input for the Load signal (17) Drain valve for the signal pressure (18) Relief valve for the signal pressure (19) Orifice (20) Pump output (21) Stop for the Minimum angle When the hydraulic system stalls under load or when the cylinders reach the end of the stroke.m. . 432E. 12 de 21 https://avspare.Piston Pump (Implement and Steering). When the discharge pressure rises to 23800 kPa to 25800 kPa (3452 psi to 3742 psi) the relief valve (18) opens sending the signal oil to the tank. This limits the pump pressure.. This limits the signal pressure. movement of the control lever into the HOLD position causes the pump to return to the low pressure standby. the system pressure increases. The pump sends out flow in order to maintain the margin over the signal pressure. During a high pressure stall. Torque Limiter 06/10/2016 11:53 a. 442E a. 420E... 434E. 430E.. 430E.Piston Pump (Implement and Steering).. 442E a. 434E..com/catalog/cat/content/i02440177/ g01293630 280-7871 Pump Control Valve Gp (Torque Limiter) The torque limiter (3) maintains the displacement of the pump in inverse proportion to the discharge pressure of the pump when the torque setting of the torque limiter is reached. This reduces engine speed and the engine could eventually stall. 06/10/2016 11:53 a.. the torque limiter (3) will destroke the pump. 13 de 21 Illustration 7 https://avspare. If the pump does not destroke. 420E. 432E. .m.. When the hydraulic demand reaches a set value. the engine will lug. The flow compensator spool (2) regulates pump flow when the system pressure and the flow requirements are below the curves in the upper right corner... 442E a. The rate of destroke will parallel the 06/10/2016 11:53 a. 432E.com/catalog/cat/content/i02440177/ g01294644 (EE) Axis for pump flow (FF) Axis for pump output pressure (A) Control of pump by torque limiter with solenoid energized.Piston Pump (Implement and Steering). The initial flow on the charts is low reflecting the standby pressure from the pump. 14 de 21 Illustration 8 https://avspare. 430E. The flow of oil decreases as the pressure in the system increases.m. Illustration4 shows the effect of the torque limiter (3) on the maximum flow rate for the machine with the torque limiter open. When oil flow is required. the pump increases the flow of oil. . Line (D) indicates the position of the torque limiter's control over the pump.. (B) Maximum pump flow (C) Maximum pump output pressure (D) Control of pump by torque limiter with solenoid de-energized.. 420E. The torque limiter will destroke the pump as the system pressure increases. 434E. When the direction selector is in the FORWARD or REVERSE .m.com/catalog/cat/content/i02440177/ torque curve of the engine. 434E. all of the power from the engine can be utilized by the power train. The delay occurs when you change the direction selector. 15 de 21 https://avspare.. The solenoid for torque control (4) is not energized until the engine reaches a higher engine speed. Parameters for the Solenoid for Torque Control 06/10/2016 11:53 a. Parameters for the Solenoid for Torque Control with the Direction Selector (Loader) Table 1 Use of the Direction Selector with the New Solenoid for Torque Control (Loader Operation) Model The Solenoid is Energized. 432E. When the solenoid is energized. the power train system and the hydraulic system will utilize the engine horsepower. there is a slight delay in operation. The Solenoid is De-energized.. High Torque Low Torque 420E 1600 rpm 1300 rpm 430E 1600 rpm 1200 rpm 432E 1600 rpm 1300 rpm 434E 1600 rpm 1300 rpm 442E 1600 rpm 1200 rpm 444E 1600 rpm 1200 rpm Table 2 lists the operating parameters for the solenoid for torque control. 420E. 430E. When you operate the machine. .. 442E a. the pump is in the low torque mode.. the new solenoid for torque control (4) will not be energized until a certain engine rpm is obtained. When the solenoid for torque control (4) is energized or de-energized due to the engine rpm. Then. When the solenoid is de-energized. the pump is in the high torque mode. Line (A) indicates when the solenoid for the torque control has been energized. The delay will help stabilize the engine and the hydraulic system.Piston Pump (Implement and Steering). The pump provides more oil flow to the hydraulic system. Piston Pump (Implement and Steering). 432E. When the direction selector is in the NEUTRAL position. 442E a. 430E. The solenoid for torque control (4) will also prevent the engine from a stall. the pump is in the low torque mode.. When the solenoid for torque control (4) is energized or de-energized due to the engine rpm. 434E.m. 420E. When the direction selector is in the NEUTRAL position. the pump is in the high torque mode. the new solenoid for torque control (4) will not be energized until a certain engine rpm is obtained. 16 de 21 https://avspare.. there is a slight delay in operation.. The Solenoid is De-energized. the solenoid for torque control (4) is de-energized in order to reduce the hydraulic demand on the engine. The delay will help stabilize the engine and the hydraulic system.com/catalog/cat/content/i02440177/ without the Direction Selector (Backhoe Operation) Table 2 The New Solenoid for Torque Control Without the Direction Selector (Backhoe Operation) Model The Solenoid is Energized. When the solenoid is energized. Torque Limiter in the Open position 06/10/2016 11:53 a.. High Torque Low Torque 420E 1200 rpm 1100 rpm 430E 1200 rpm 1100 rpm 432E 1200 rpm 1100 rpm 434E 1200 rpm 1100 rpm 442E 1200 rpm 1100 rpm 444E 1200 rpm 1100 rpm Table 3 lists the operating parameters for the new solenoid for torque control (4) without the use of the direction selector. . When the solenoid is de-energized. 434E..m.. 17 de 21 Illustration 9 https://avspare.. 420E. .. 432E.Piston Pump (Implement and Steering).com/catalog/cat/content/i02440177/ g01293626 (1) Torque Control (1A) Spring (2) Flow Compensator (2A) Spring (3) Torque Limiter (4) Solenoid for Torque Control (5) Pump controller 06/10/2016 11:53 a. 430E. 442E a. 432E. 18 de 21 https://avspare. When the spool for torque control (1) moves up. The actuator piston moves to the right. 420E. The supply oil acts against the actuator (10) . . the spool opens a path for the supply oil. Oil drains to the tank. 442E a. This allows the supply oil to flow to actuator (10) . The pump moves to maximum displacement.. a pressure drop occurs across orifice (19) . The pressure in the line between the torque control (1) and the torque limiter (3) increases. The discharge oil of the pump that is below the torque control causes the torque control (1) to move up slightly.. The pressure setting of the torque limiter (3) varies with the swashplate angle due to the mechanical linkage between the swashplate (9) and the torque limiter (3) .com/catalog/cat/content/i02440177/ (6) Pump (7) Bias piston (8) Spring (9) Swashplate (10) Actuator piston (12) Piston (intake) (13) Piston (14) Outlet manifold for the backhoe (15) Relief valve for the margin pressure (flushing valve) (16) Input for the Load signal (17) Drain valve for the signal pressure (18) Relief valve for the signal pressure (19) Orifice (20) Pump output (21) Stop for the Minimum angle (22) Relay (23) ECM The torque limiter (3) monitors the pump swashplate angle and the pump discharge pressure. the mechanical linkage increases the force on the springs of the torque limiter (3) .Piston Pump (Implement and Steering). Destroking the pump reduces the output of the pump in order to prevent the engine from stalling.m. As the oil drains to the tank. The torque limiter opens. This destrokes the pump. As the swashplate angle decreases. This increases the pressure setting of the torque limiter (3) . the flow compensator (2) receives a signal from a valve. 434E. When a higher flow rate is required. 06/10/2016 11:53 a.. 430E.. This lowers the signal pressure in the line to the torque limiter (3) . 420E. 430E.. 432E... 434E. . 19 de 21 https://avspare.Piston Pump (Implement and Steering).m. 442E a.com/catalog/cat/content/i02440177/ The Solenoid for Torque Control is Energized and the Torque Limiter is Open Illustration 10 g01293628 (1) Torque Control (1A) Spring (2) Flow Compensator (2A) Spring (3) Torque Limiter 06/10/2016 11:53 a.. At the same time..m. Pump discharge oil flows through the solenoid for torque control (4) and a small orifice. a higher work port pressure occurs. the force on the spring for the torque limiter increases.Piston Pump (Implement and Steering). 06/10/2016 11:53 a. 442E a. This increases the pressure on the top of the spool for torque control (1) . 20 de 21 https://avspare. The flow from the pump increases. Full pump pressure is always available. 430E. Due to the mechanical linkage between the swashplate (9) and the torque limiter (3) . The spool remains seated.. The higher force on the spring for the swashplate (9) will destroke the pump at a higher pressure. 432E. . The position of the two spools will partially upstroke the pump in order to meet the higher flow demand and the demand of the system pressure.. Flow from the pump is regulated in order to maintain the maximum input torque from the engine. 420E. 434E. the new solenoid for torque control is ENERGIZED.. The higher work port pressure creates a higher signal pressure that keeps the flow compensator (2) in the down position.com/catalog/cat/content/i02440177/ (4) Solenoid for Torque Control (5) Pump controller (6) Pump (7) Bias piston (8) Spring (9) Swashplate (10) Actuator piston (12) Piston (intake) (13) Piston (14) Outlet manifold for the backhoe (15) Relief valve for the margin pressure (flushing valve) (16) Input for the Load signal (17) Drain valve for the signal pressure (18) Relief valve for the signal pressure (19) Orifice (20) Pump output (21) Stop for the Minimum angle (22) Relay (23) ECM When the correct engine speed for the machine operation has been obtained. . 420E. descriptions.m. 434E. Volvo. Inc. Doosan. AVSpare. Hitachi. Komatsu.com/catalog/cat/content/i02440177/ RECENT 3824996 CATERPILLAR bearing HITACHI 1132907 CATERPILLAR 0951519 CATERPILLAR 3534515 CATERPILLAR PARTS  Caterpillar  Hitachi  Volvo pro AUTODATA  Caterpillar  Volvo Impact  Volvo Prosis  Hitachi HOP  Bosch ESPI  Part list | Spare parts The names Cat. Caterpillar. Hyundai or any other original equipment manufacturers are registered trademarks of the respective original equipment manufacturers. 21 de 21 https://avspare. All manufacturer's names and descriptions are for reference only. 432E. JCB.. All names. 06/10/2016 11:53 a.com is in no way associated with any of the manufacturers we have listed. . 430E.. numbers and symbols are used for reference purposes only. John Deere.. 442E a. Cat® and Caterpillar® are registered trademarks of Caterpillar.Piston Pump (Implement and Steering).