Case Cx210B 290B Hydraulics-21113C200153.pdf
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Hydraulics Section

Function List

Hydraulic Components

61_Hydraulic.pdf

	Hydraulic components layout

	Negative control circuits

		For no load operation, this circuit sets the hydraulic pump discharge quantity to minimum to reduce horsepower consumption.

		Negative Control Circuit (power save solenoid OFF)

		When the remote control valve operation lever is set to neutral, the discharged oil from hydraulic pumps A1 and A2 goes from the...

		The discharged oil from hydraulic pump A3 enters the 5-stack solenoid valve P port, flows through the power save solenoid valve,...

		The negative control pressure oil separated from the center bypass passage is fed from the Ps1 and Ps2 ports to the hydraulic pump Pi1 and Pi2 ports, moves the pump tilt revolution to the low flow side, and reduces the discharge flow.

		1

		P1 negative control relief

		11

		N1 negative control pressure sensor

		2

		P2 negative control relief

		12

		P1 pressure sensor

		3

		Control valve

		13

		P2 pressure sensor

		4

		Travel pilot pressure sensor

		14

		N2 negative control pressure sensor

		5

		Upper side pilot pressure sensor

		15

		Horsepower control proportional valve

		6

		Computer A

		16

		P1 flow control proportional valve

		7

		Console lever lock switch

		17

		Hydraulic pump

		8

		Lever lock

		18

		Check

		9

		Power save

		19

		Oil cooler

		10

		5-stack solenoid valve

	Negative Control Circuit

		The purpose of this control is to reduce fuel consumption during standby by reducing the back pressure for the negative control signal.

		When the remote control valve is set to neutral, the non-operation state signal enters the computer A from the upper side pilot ...

		The pressurized oil from the control valve negative control relief valve Pn1 and Pn2 ports goes through the power save solenoid valve and returns to the hydraulic oil tank.

		Therefore, the negative control relief valve set pressure is switched to low pressure to further reduce the A1 and A2 pump discharge pressure.

		With the system running this way, the negative control signal is cut off and the P1 and P2 pump discharged volume quantity increases.

		The discharged oil from pilot pump A3 enters the 5-stack solenoid valve P port, flows through the power save solenoid valve, is ...

		At the same time, the discharged oil from the A3 pilot pump is fed to the hydraulic pump P1 port by the signal from the computer...

		1

		Control valve

		10

		P1 pressure sensor

		2

		Travel pilot pressure sensor

		11

		P2 pressure sensor

		3

		Upper side pilot pressure sensor

		12

		N2 negative control pressure sensor

		4

		Computer A

		13

		Horsepower control proportional valve

		5

		Console lever lock switch

		14

		P1 flow control proportional valve

		6

		Lever lock

		15

		Hydraulic pump

		7

		Power save

		16

		Check

		8

		5-stack solenoid valve

		17

		Oil cooler

		9

		N1 negative control pressure sensor

	Negative Control Circuit

		As an example, this section explains the bucket close operations.

		By moving the remote control valve to the bucket close side, the pilot pressure oil is fed via the cushion valve to the control valve Pb7 port and switches the bucket spool to the close side.

		The discharged oil from the hydraulic pump A2 enters the control valve P2 port, is fed to the bucket spool, flows into the bucket cylinder bottom side because of the spool switching and carries out the bucket close operation.

		At the same time, the upper side pilot pressure sensor signal is detected and through the signal output from the computer A to s...

		Because the bucket spool switches and the pressurized oil on the center bypass is cut off, the Pi2 pump negative control pressure oil from the Ps2 port is eliminated, the pump revolution tilt moves to the increase side, and the flow is increased.

		Also, the command current to the pump P1 flow control proportional valve is lowered and the pressurized oil from the A3 hydrauli...

		1

		Control valve

		12

		Power save

		2

		Travel pilot pressure sensor

		13

		5-stack solenoid valve

		3

		Upper side pilot pressure sensor

		14

		P1 pressure sensor

		4

		Cushion valve

		15

		P2 pressure sensor

		5

		Bucket (close)

		16

		N1 negative control pressure sensor

		6

		Bucket (open)

		17

		N2 negative control pressure sensor

		7

		Bucket cylinder

		18

		P1 flow control proportional valve

		8

		Computer A

		19

		Hydraulic pump

		9

		Remote control valve (boom, bucket)

		20

		Check

		10

		Console lever lock switch

		21

		Oil cooler

		11

		Lever lock

	Travel circuit

		Low-Speed Travel Circuit

		Sets the travel motor two-stage tilt revolution angle to a large angle to set low speed

		As an example, this section explains the forward travel operation.

		The travel motor two-stage tilt revolution angle is a large angle side. Even if the travel switch is set to the high-speed side, switching the key switch OFF, then ON again always returns the system to this state.

		By operating the travel remote control valve to the forward side, the pilot pressure oil is fed to the control valve Pa1 port and switches the left travel spool to the forward side.

		At the same time, the oil is also fed to the Pa6 port to switch the right travel spool to the forward side.

		The discharged oil from hydraulic pump A1 enters the control valve P1 port and the discharged oil from hydraulic pump A2 enters ...

		The return oil from the travel motor goes through the left and right travel spools and returns to the hydraulic oil tank.

		The travel high-speed solenoid valve goes OFF, the travel motor Ps port oil connects with the tank line and the travel motor revolution tilt angle goes to the large revolution tilt side.

	Travel circuit

		Sets the travel motor two-stage tilt revolution angle to a small angle to set high speed.

		The speed is automatically switched to low speed according to the load pressure on the travel motor.

		In order to prevent drift at high speed, if the travel pressure becomes 25.8 MPa or higher, the speed is set to low speed.

		As an example, this section explains the forward travel operation.

		Sets the travel motor two-stage tilt revolution angle to a small angle to set high speed. The travel motor has an auto switch function that switches the speed from high speed to low speed according to the load pressure on the travel motor.

		By operating the travel remote control valve to the forward side, the pilot pressure oil is fed to the control valve Pa1 port and switches the left travel spool to the forward side.

		At the same time, the oil is also fed to the Pa6 port to switch the right travel spool to the forward side.

		The discharged oil from hydraulic pump A1 enters the control valve P1 port and the discharged oil from hydraulic pump A2 enters ...

		The return oil from the travel motor goes through the left and right travel spools and returns to the hydraulic oil tank.

		Electrical signals are sent to the computer A by operation of the high-speed travel select switch and the computer A sends elect...

		1

		Travel motor

		10

		Console lever lock switch

		2

		High speed travel select switch

		11

		Hydraulic pump

		3

		Computer A

		12

		Travel remote control valve

		4

		Control valve

		13

		Check

		5

		Travel (left)

		14

		Oil cooler

		6

		Travel (right)

		15

		Backward left

		7

		Travel speed

		16

		Forward left

		8

		Lever lock

		17

		Forward right

		9

		5-stack solenoid valve

		18

		Backward right

	Travel circuit

		Traveling with other equipment opration, travel is held straight without curving.

		As an example, this section explains simultaneous forward travel and boom up operations.

		By operating the travel remote control valve to the forward side, the pilot pressure oil is fed to the control valve Pa1 port and switches the left travel spool to the forward side.

		In the same way, oil is also fed to the Pa6 port to switch the right travel spool to the forward side.

		Furthermore, the right forward travel pilot pressure oil separated internally from the control valve Pa6 port switches the strai...

		The discharged oil from hydraulic pump A1 enters the control valve P1 port and the discharged oil from hydraulic pump A2 enters ...

		If a boom-up operation is carried out during travel, the pilot pressure oil is fed via the cushion valve to the control valve Pa4 port and switches the boom (1) and (2) spools to the up side.

		The upper side (boom, arm, bucket, swing, option) pilot pressure oil separated internally from the control valve Pa4 port is fed to the straight travel valve via the straight travel signal (left) and the straight travel spool is switched.

		The amount of switching of the straight travel spool varies with the upper side pilot pressure.

		(Because the pilot pressure is low for slight upper side operation, the amount of switching of the straight travel spool is slight to prevent sudden reduction in the travel speed.)

		Because the straight travel valve is switched, it is possible for the control valve P1 pressurized oil to drive the left and right travel motors and for the control valve P2 pressurized oil to drive the boom.

		Because the left and right motors are driven by one pump, the left and right motors have the same pressure and straight travel i...

		The same operations are carried out when travel and an upper side actuator other than for the boom are operated simultaneously.

	Travel circuit

		For travel single operation, the increased horsepower signal is output to the hydraulic pump horsepower control proportional valve from the computer A by the travel pilot pressure sensor input signal.

		The hydraulic pump discharged volume quantity is increased by the increased horsepower signal to the horsepower control proportional valve from the computer A.

		Conditions under which the travel increased horsepower control is entered

		Travel pilot pressure 0.5 MPa or higher.

		SP mode

		Conditions under which the travel increased horsepower control is ended

		Travel pilot pressure 0.3 MPa or lower.

		AUTO mode, H mode

		1

		Travel motor

		13

		P1 pressure sensor

		2

		Travel remote control valve

		14

		P2 pressure sensor

		3

		Travel speed

		15

		N1 negative control pressure sensor

		4

		Lever lock

		16

		N2 negative control pressure sensor

		5

		5-stack solenoid valve

		17

		Hydraulic pump

		6

		Console lever lock switch

		18

		Check

		7

		High speed travel select switch

		19

		Oil cooler

		8

		Computer A

		20

		Backward left

		9

		Control valve

		21

		Forward left

		10

		Travel (right)

		22

		Forward right

		11

		Travel (left)

		23

		Backward right

		12

		Travel pilot pressure sensor

	Boom Circuits

		Boom only The flow is merged internally by switching the boom (2) spool to raise the speed.

		By operating the remote control valve to the boom-up side, the pilot pressure oil is fed via the cushion valve to the control va...

		The discharged oil from hydraulic pump A1 enters the control valve P1 port, is fed from the parallel passage to the boom (2) spo...

		The boom cylinder rod side return oil goes through the boom (1) spool and returns to the hydraulic oil tank.

		1

		Cushion valve

		13

		Travel pilot pressure sensor

		2

		Boom (up)

		14

		Upper side pilot pressure sensor

		3

		Boom (down)

		15

		Console lever lock switch

		4

		Boom (2)

		16

		Monitor display

		5

		Remote control valve (boom, bucket)

		17

		Power up

		6

		Lever lock

		18

		Computer A

		7

		Boost relief

		19

		P1 pressure sensor

		8

		5-stack solenoid valve

		20

		P2 pressure sensor

		9

		Control valve

		21

		Hydraulic pump

		10

		Boom load hold valve check

		22

		Check

		11

		Boom (1)

		23

		Oil cooler

		12

		Boom cylinder

	Boom Circuits

		Compound The swing priority variable metering spool is switched to make movement in arm-in compound operation smooth.

		As an example, this section explains the boom-up + arm-in compound operation (leveling work).

		For bed digging work, the boom-up pilot pressure oil is fed to the Pbu port, the swing priority variable orifice is moved to the left side and the restriction on the flow to the arm is ended to smooth the arm movement.

		By operating the remote control valve to the boom up side and arm-in side, the pilot pressure oil is fed via the cushion valve t...

		The discharged oil from hydraulic pump A1 enters the control valve P1 port and is fed from the parallel passage to the boom (2) ...

		The arm cylinder rod side return oil goes through the load hold valve check valve and the arm (1) spool and returns to the hydraulic oil tank.

		The discharged oil from hydraulic pump A2 enters the control valve P2 port and is fed from the parallel passage to the boom (1) ...

		The boom cylinder rod side return oil goes through the boom (1) spool and returns to the hydraulic oil tank.

		1

		Arm cylinder

		12

		Arm (1)

		23

		Travel pilot pressure sensor

		2

		Arm (in)

		13

		Boom (2)

		24

		Upper side pilot pressure sensor

		3

		Arm (out)

		14

		Arm load hold valve spool

		25

		Console lever lock switch

		4

		Boom (up)

		15

		Load hold valve check

		26

		Monitor display

		5

		Boom (down)

		16

		Regeneration release valve

		27

		Power up

		6

		Cushion valve

		17

		Control valve

		28

		Computer A

		7

		Remote control valve (boom, bucket)

		18

		Swing priority variable orifice

		29

		P1 pressure sensor

		8

		Remote control valve (arm, swing)

		19

		Arm (2)

		30

		P2 pressure sensor

		9

		Lever lock

		20

		Boom load hold valve check

		31

		Hydraulic pump

		10

		Boost relief

		21

		Boom (1)

		32

		Check

		11

		5-stack solenoid valve

		22

		Boom cylinder

		33

		Oil cooler

	Boom Circuits

		Regeneration within the boom spool is used to increase speed and prevent cavitation.

		By moving the remote control valve to the boom down side, the pilot pressure oil is fed via the cushion valve to the control valve Pb8 port and switches the boom (1) spool to the down side.

		The discharged oil from hydraulic pump A2 enters the control valve P2 port and is fed from the parallel passage to the boom (1) spool. Switching the spool lets the oil flow into the boom cylinder rod side and carries out the boom down operation.

		The pilot pressure oil from the Pb8 port separated in the internal path is fed to the load hold valve spool and moves the spool ...

		The boom cylinder bottom side pressurized oil goes through the load hold valve check valve and is metered by the boom (1) spool ...

		Because the circuit is configured in such a way that even if the boom (1) spool is at full stroke, negative control pressure is ...

		1

		Load hold valve check

		13

		5-stack solenoid valve

		2

		Check

		14

		Control valve

		3

		Oil cooler

		15

		P2 pressure sensor

		4

		P1 pressure sensor

		16

		Hydraulic pump

		5

		Orifice

		17

		Boom cylinder

		6

		Bleed-off

		18

		Boom (1)

		7

		Cushion valve

		19

		Travel pilot pressure sensor

		8

		Boom (up)

		20

		Upper side pilot pressure sensor

		9

		Boom (down)

		21

		Console lever lock switch

		10

		Remote control valve (boom, bucket)

		22

		Monitor display

		11

		Lever lock

		23

		Computer A

		12

		Boost relief

	Boom Circuits

		High pressure is suppressed with the bleed-off circuit and tilting is mitigated.

		By operating the remote control valve all the way to the boom down side at once, even if the boom spool goes its full stroke, ne...

		1

		Load hold valve check

		12

		Control valve

		2

		Check

		13

		P2 pressure sensor

		3

		Oil cooler

		14

		Hydraulic pump

		4

		Bleed-off

		15

		Boom cylinder

		5

		Cushion valve

		16

		Boom (1)

		6

		Boom (up)

		17

		Travel pilot pressure sensor

		7

		Boom (down)

		18

		Upper side pilot pressure sensor

		8

		Remote control valve (boom, bucket)

		19

		Console lever lock switch

		9

		Lever lock

		20

		Monitor display

		10

		Boost relief

		21

		Computer A

		11

		5-stack solenoid valve

		22

		P1 pressure sensor

	Boom Circuits

		The load hold valve built into the control valve is speed up.

		When the remote control valve boom operation lever is in neutral, the oil at the boom cylinder bottom side is sealed by the load hold valve check valve, reducing internal leakage from the main spool and reducing the natural drop of the boom.

		By moving the remote control valve to the boom down side, the pilot pressure oil is fed via the cushion valve to the control valve Pb8 port and switches the boom spool to the down side.

		The discharged oil from hydraulic pump A2 enters the control valve P2 port and is fed from the parallel passage to the boom (1). Switching the spool lets the oil flow into the boom cylinder bottom side and carries out the boom down operation.

		The pilot pressure oil from the Pb8 port separated in the internal path is fed to the load hold valve spool and moves the spool ...

		The boom cylinder bottom side pressurized oil goes through the load hold valve check valve and the boom (1) spool and returns to the hydraulic oil tank.

		1

		Boom load hold valve check

		12

		Oil cooler

		2

		Load hold valve spool

		13

		Boom cylinder

		3

		Cushion valve

		14

		Boom (1)

		4

		Boom (up)

		15

		Travel pilot pressure sensor

		5

		Boom (down)

		16

		Upper side pilot pressure sensor

		6

		Remote control valve (boom, bucket)

		17

		Console lever lock switch

		7

		Lever lock

		18

		Monitor display

		8

		Boost relief

		19

		Computer A

		9

		5-stack solenoid valve

		20

		P1 pressure sensor

		10

		Control valve

		21

		P2 pressure sensor

		11

		Check

		22

		Hydraulic pump

	Arm Circuits

		The flow is merged internally by switching the arm (2) spool to raise the speed.

		By moving the remote control valve to the arm-out side, the pilot pressure oil is fed via the cushion valve to the control valve Pa5 port and Pa9 port and switches the arm (1) and (2) spools to the open side.

		The discharged oil from hydraulic pump A1 enters the control valve P1 port and is fed from the center bypass passage to the arm ...

		Switching the arm spool lets the oil flow through the load hold valve check valve and into the arm cylinder rod side, carrying out the arm-out operation.

		The arm cylinder bottom side return oil goes through the arm (1) and (2) spools and returns to the hydraulic oil tank.

		1

		Arm cylinder

		13

		Travel pilot pressure sensor

		2

		Arm (out)

		14

		Upper side pilot pressure sensor

		3

		Arm (in)

		15

		Console lever lock switch

		4

		Cushion valve

		16

		Monitor display

		5

		Remote control valve (arm, swing)

		17

		Power up

		6

		Lever lock

		18

		Computer A

		7

		Boost relief

		19

		P1 pressure sensor

		8

		5-stack solenoid valve

		20

		P2 pressure sensor

		9

		Control valve

		21

		Hydraulic pump

		10

		Load hold valve check

		22

		Check

		11

		Arm (1)

		23

		Oil cooler

		12

		Arm (2)

		24

		Cushion valve

	Arm Circuits

		The speed for compound operation is raised by the forced regeneration release valve in the control valve.

		By moving the remote control valve to the arm-in side, the pilot pressure oil is fed via the cushion valve to the control valve Pb5 port and Pb9 port and switches the arm (1) and (2) spools to the in side.

		The discharged oil from hydraulic pump A1 enters the control valve P1 port and is fed from the center bypass passage to the arm ...

		Switching the arm spool lets the oil flow into the arm cylinder bottom side and carries out the arm-in operation.

		The pilot pressure oil from the Pb5 port separated in the internal path is fed to the load hold valve spool and moves the spool ...

		The arm cylinder rod side pressurized oil goes through the load hold valve check valve and the arm (1) spool and is metered by t...

		1

		Load hold valve spool

		11

		Remote control valve (arm, swing)

		21

		Console lever lock switch

		2

		Load hold valve check

		12

		Lever lock

		22

		Monitor display

		3

		Oil cooler

		13

		Boost relief

		23

		Power up

		4

		Regeneration check

		14

		5-stack solenoid valve

		24

		Computer A

		5

		Orifice large

		15

		Control valve

		25

		P1 pressure sensor

		6

		Orifice small

		16

		Arm cylinder

		26

		P2 pressure sensor

		7

		Forced regeneration release valve

		17

		Arm (1)

		27

		Hydraulic pump

		8

		Arm (in)

		18

		Arm (2)

		28

		Check

		9

		Arm (out)

		19

		Travel pilot pressure sensor

		10

		Cushion valve

		20

		Upper side pilot pressure sensor

	Arm Circuits

		The load hold valve built into the control valve is released to make the arm-in operation possible.

		When the remote control valve arm operation lever is in neutral, the oil at the arm cylinder rod side is sealed by the load hold valve check valve, reducing internal leakage from the main spool and reducing the natural drop of the arm.

		By moving the remote control valve to the arm-in side, the pilot pressure oil is fed via the cushion valve to the control valve Pb5 port and Pb9 port and switches the arm (1) and (2) spools to the in side.

		The discharged oil from hydraulic pump A1 enters the control valve P1 port and is fed from the center bypass passage to the arm ...

		Switching the arm spool lets the oil flow into the arm cylinder bottom side and carries out the arm-in operation.

		The pilot pressure oil from the Pb5 port separated in the internal path is fed to the load hold valve spool and moves the spool ...

		The arm cylinder rod side pressurized oil goes through the load hold valve check valve and the arm (1) spool and returns to the hydraulic oil tank.

		1

		Load hold valve spool

		14

		Arm (2)

		2

		Load hold valve check

		15

		Travel pilot pressure sensor

		3

		Oil cooler

		16

		Upper side pilot pressure sensor

		4

		Arm (in)

		17

		Console lever lock switch

		5

		Arm (out)

		18

		Monitor display

		6

		Cushion valve

		19

		Power up

		7

		Remote control valve (arm, swing)

		20

		Computer A

		8

		Lever lock

		21

		P1 pressure sensor

		9

		Boost relief

		22

		P2 pressure sensor

		10

		5-stack solenoid valve

		23

		Hydraulic pump

		11

		Control valve

		24

		Check

		12

		Arm cylinder

		13

		Arm (1)

	Arm Circuits

		Increases the hydraulic pump discharge volume for arm-in operations.

		For the arm-in operation, the increased horsepower signal is output to the hydraulic pump horsepower control proportional valve from the computer A by the arm pilot pressure sensor input signal and P1 pressure sensor and P2 pressure sensor input signals.

		The hydraulic pump discharged vloume quantity is increased by the increased horsepower signal to the horsepower control proportional valve from the computer A.

		Condition under which the arm-in increased horsepower control is entered

		Arm-in pilot pressure 0.5 MPa or higher (arm-in operation)

		P1 + P2 � 45 MPa

		Conditions under which the arm-in increased horsepower control is ended

		Arm-in pilot pressure 0.3 MPa or lower (arm-in operation end)

		P1 + P2 � 45 MPa

		When either occurs

		1

		Arm (in)

		13

		Travel pilot pressure sensor

		2

		Arm (out)

		14

		Upper side pilot pressure sensor

		3

		Cushion valve

		15

		Console lever lock switch

		4

		Remote control valve (arm, swing)

		16

		Monitor display

		5

		Lever lock

		17

		Computer A

		6

		Boost relief

		18

		N1 negative control pressure sensor

		7

		5-stack solenoid valve

		19

		P1 pressure sensor

		8

		Arm cylinder

		20

		P2 pressure sensor

		9

		Arm pilot pressure sensor

		21

		N2 negative control pressure sensor

		10

		Control valve

		22

		Hydraulic pump

		11

		Arm (1)

		23

		Check

		12

		Arm (2)

		24

		Oil cooler

	Bucket Circuit

		By moving the remote control valve to the bucket open side, the pilot pressure oil is fed via the cushion valve to the control valve Pa7 port and switches the bucket spool to the open side.

		The discharged oil from hydraulic pump A2 enters the control valve P2 port and is fed from the parallel passage to the bucket spool. Switching the spool lets the oil flow into the bucket cylinder rod side and carries out the bucket open operation.

		The bucket cylinder bottom side pressurized oil goes through the spool and returns to the hydraulic oil tank.

		1

		Cushion valve

		12

		Upper side pilot pressure sensor

		2

		Bucket (close)

		13

		Console lever lock switch

		3

		Bucket (open)

		14

		Monitor display

		4

		Remote control valve (boom, bucket)

		15

		Power up

		5

		Lever lock

		16

		Computer A

		6

		Boost relief

		17

		P1 pressure sensor

		7

		5-stack solenoid valve

		18

		P2 pressure sensor

		8

		Control valve

		19

		Hydraulic pump

		9

		Bucket

		20

		Check

		10

		Bucket cylinder

		21

		Oil cooler

		11

		Travel pilot pressure sensor

	Bucket Circuit

		Regeneration within the bucket spool is used to increase speed and prevent vacuum.

		By moving the remote control valve to the bucket close side, the pilot pressure oil is fed via the cushion valve to the control valve Pb7 port and switches the bucket spool to the close side.

		The discharged oil from hydraulic pump A2 enters the control valve P2 port and is fed from the parallel passage to the bucket spool. Switching the spool lets the oil flow into the bucket cylinder bottom and carries out the bucket close operation.

		The bucket cylinder rod side oil goes through the bucket spool regeneration orifice. Through this, the return oil pushes open th...

		1

		Regeneration check

		13

		Bucket cylinder

		2

		Oil cooler

		14

		Travel pilot pressure sensor

		3

		Orifice

		15

		Upper side pilot pressure sensor

		4

		Cushion valve

		16

		Console lever lock switch

		5

		Bucket (close)

		17

		Monitor display

		6

		Bucket (open)

		18

		Power up

		7

		Remote control valve (boom, bucket)

		19

		Computer A

		8

		Lever lock

		20

		P1 pressure sensor

		9

		Boost relief

		21

		P2 pressure sensor

		10

		5-stack solenoid valve

		22

		Hydraulic pump

		11

		Control valve

		23

		Check

		12

		Bucket

	Cushion Circuit

		Softens the shock through the work of the cushion valve with heat circuit.

		These circuit is attached to the boom and arm pilot lines.

		There is no soft 

		As examples, this section explains the cases when an arm-out operation is carried out, when an arm-out operation is stopped, and when an arm-out operation is followed by an arm-in operation.

		When a remote control valve arm-out operation is carried out, the pilot pressure oil enters from the remote control valve 2 port into the cushion valve, pushes up the internal check valve, and is fed to the control valve Pa5 port and Pa9 port.

		At the same time, the cushion valve cushion spool is switched to the left.

		The arm-in side oil pushed out from the control valve Pa9 and Pb 5 ports passes from the cushion valve B port through the cushion spool switched to the left and returns to the hydraulic oil tank.

		At this time, the warmed oil from the return line enters the remote control valve through the cushion spool from the cushion valve R port and returns to the hydraulic oil tank, so heat performance is improved.

		1

		Arm (in)

		10

		Control valve

		2

		Arm (out)

		11

		Arm (1)

		3

		Cushion spool

		12

		Arm (2)

		4

		Orifice

		13

		Console lever lock switch

		5

		Check valve

		14

		Hydraulic pump

		6

		Cushion valve

		15

		Check

		7

		Remote control valve (arm, swing)

		16

		Oil cooler

		8

		Lever lock

		17

		Shut off valve

		9

		5-stack solenoid valve

	Cushion Circuit

		When the remote control valve arm-out operation lever is returned to neutral, the oil pushed out from the control valve Pa5 and ...

		Through this orifice, the arm spool moves to the neutral position without returning suddenly, so the cushioning is improved.

		1

		Arm (in)

		9

		Control valve

		2

		Arm (out)

		10

		Arm (1)

		3

		Cushion spool

		11

		Arm (2)

		4

		Orifice

		12

		Console lever lock switch

		5

		Cushion valve

		13

		Hydraulic pump

		6

		Remote control valve (arm, swing)

		14

		Check

		7

		Lever lock

		15

		Oil cooler

		8

		5-stack solenoid valve

		16

		Cushion spool

	Cushion Circuit

		When the lever is operating all at once from an arm-out operation to an arm-in operation (arm drift operation), the pilot pressu...

		At the same time, the cushion valve cushion spool is switched to the right.

		At this time, the oil pushed out from the Pa5 port and Pa9 port does not pass through the cushion orifice, but passes through the cushion spool that has been switched to the right and returns to the hydraulic oil tank, so response is improved.

		1

		Arm (in)

		9

		Control valve

		2

		Arm (out)

		10

		Arm (1)

		3

		Cushion spool

		11

		Arm (2)

		4

		Orifice

		12

		Console lever lock switch

		5

		Cushion valve

		13

		Hydraulic pump

		6

		Remote control valve (arm, swing)

		14

		Check

		7

		Lever lock

		15

		Oil cooler

		8

		5-stack solenoid valve

	Cushion Circuit

		The pilot line is equipped with a heat circuit to prevent response delay at low temperatures.

		When the remote control valve operation lever is set to neutral, the discharged oil from hydraulic pumps A1 and A2 goes from the control valve P1 and P2 ports through the center bypass passage, and returns to the hydraulic oil tank.

		The pressurized oil from the control valve T8 port is fed to the cushion valve R port and returns through the cushion spool to the hydraulic oil tank.

		By circulating the oil inside the cushion spool, the temperature of the oil in the cushion valve is raised to improve heat performance.

		1

		Arm (in)

		7

		Control valve

		2

		Arm (out)

		8

		Console lever lock switch

		3

		Cushion valve

		9

		Hydraulic pump

		4

		Remote control valve (arm, swing)

		10

		Check

		5

		Lever lock

		11

		Oil cooler

		6

		5-stack solenoid valve

	Auto Power Boost Circuit (bucket close)

		Boost the main relief pressure from 34.3 MPa to 36.8 MPa according to the engine load ratio and circuit pressure.

		When an attachment is operated, this circuit boosts the control valve main relief pressure from 34.3 MPa to 36.8 MPa according to the engine load ratio and hydraulic load pressure, then ends the pressure boost after 8 seconds.

		As an example, this section explains bucket close operations.

		By moving the remote control valve to the bucket close side, the pilot pressure oil is fed via the cushion valve to the control valve Pb7 port and switches the bucket spool to the close side.

		At the same time, the pressurized oil separated from the pilot internal passage is detected and the upper side pilot pressure se...

		The option circuit is not boosted during a travel operation.

		1

		Cushion valve

		11

		Upper side pilot pressure sensor

		2

		Bucket (close)

		12

		Console lever lock switch

		3

		Bucket (open)

		13

		Power up

		4

		Remote control valve (boom, bucket)

		14

		Monitor display

		5

		Lever lock

		15

		Computer A

		6

		Boost relief

		16

		P1 pressure sensor

		7

		5-stack solenoid valve

		17

		P2 pressure sensor

		8

		Control valve

		18

		Hydraulic pump

		9

		Bucket

		19

		Check

		10

		Bucket cylinder

		20

		Oil cooler

	Swing Circuits

		When the engine is stopped, swing parking works.

		When the machine is stopped (the key is switched OFF), the swing motor P port oil goes from the swing brake solenoid C2 port through the lever lock solenoid and returns to the hydraulic oil tank, holding the swing parking brake hold status.

		1

		Swing motor

		9

		Lever lock

		2

		Cushion valve

		10

		Swing brake

		3

		Right swing

		11

		5-stack solenoid valve

		4

		Left swing

		12

		Console lever lock switch

		5

		Swing pilot pressure sensor

		13

		Computer A

		6

		Remote control valve (arm, swing)

		14

		Control valve

		7

		Check

		15

		Upper side pilot pressure sensor

		8

		Oil cooler

		16

		Hydraulic pump

	Swing Circuits

		In order to increase the cylinder bore and attachment speed, the pump maximum flow was increased, but in order to not increase t...

		This control is for suppressing increases in the swing speed accompanying increased pump flow.(Only in SP mode)

		For swing-only operation, due to the swing pilot pressure sensor and P1 pressure sensor input electric signal, the computer A outputs a signal to the P1 hydraulic pump flow control proportional valve.

		The discharged oil from the A3 hydraulic pump is fed to the P1 flow control proportional valve.

		The hydraulic pump A1 side discharge flow is reduced to 200 L 

		Conditions under which the swing speed limit control is entered

		Swing only full lever operation

		No travel operation

		Work mode SP

		Conditions under which the swing speed limit control is ended

		Upper side operation other than boom down

		? Gradual end (to reduce shock)

		Travel operation

		? Immediate end (to avoid back lash)

		Option operation

		1

		Swing motor

		13

		Swing brake

		2

		Swing

		14

		5-stack solenoid valve

		3

		Cushion valve

		15

		Console lever lock switch

		4

		Right swing

		16

		N1 negative control pressure sensor

		5

		Left swing

		17

		P1 pressure sensor

		6

		Swing pilot pressure sensor

		18

		P1 flow control proportional valve

		7

		Remote control valve (arm, swing)

		19

		Hydraulic pump

		8

		Control valve

		20

		Horsepower control proportional valve

		9

		Travel pilot pressure sensor

		21

		P2 pressure sensor

		10

		Upper side pilot pressure sensor

		22

		Check

		11

		Computer A

		23

		Oil cooler

		12

		Lever lock

	Swing Circuits

		When swing is operated alone, if swing is started with a sudden lever operation, the pump flow is reduced with the proportional valve installed on the swing pump (front side).

		Normally, this control eliminates the excess oil discharged from the swing relief valve and reduces the horsepower consumption.

		When the swing speed rises, the pump discharge pressure falls, so the pump flow is increased gradually while it is detected with the sensor.

		This control aims for an energy saving effect by controlling the pump in such a way as to minimize the excess oil drained from the swing motor relief valve for the starting pressure boost for a sudden swing-only operation.

		When a swing operation starts, due to the swing pilot pressure sensor and P1 pressure sensor input electrical signals, the computer A outputs a signal to the hydraulic pump P1 flow control proportional valve.

		The discharged oil from the A3 hydraulic pump is fed to the P1 flow control proportional valve.

		The output signal from the computer A to the P1 flow control proportional valve controls the pilot pressure to reduce the hydrau...

		Swing relief cut-off control is executed when all the conditions below are satisfied.

		No travel operation

		Swing-only sudden operation or swing + boom down operation

		Swing relief cut-off control ends when a condition below is satisfied.

		When swing operation is stopped

		Travel, boom-up, arm out 

		1

		Swing motor

		13

		Swing brake

		2

		Swing

		14

		5-stack solenoid valve

		3

		Cushion valve

		15

		Console lever lock switch

		4

		Right swing

		16

		N1 negative control pressure sensor

		5

		Left swing

		17

		P1 pressure sensor

		6

		Swing pilot pressure sensor

		18

		P1 flow control proportional valve

		7

		Remote control valve (arm, swing)

		19

		Hydraulic pump

		8

		Control valve

		20

		Horsepower control proportional valve

		9

		Travel pilot pressure sensor

		21

		P2 pressure sensor

		10

		Upper side pilot pressure sensor

		22

		Check

		11

		Computer A

		23

		Oil cooler

		12

		Lever lock

	Swing Circuits

		Swing pushing is obtained by the swing priority variable orifice built into the control valve.

		The wing priority variable orifice also works to secure the arm flow for bed metering.

		The swing pilot pressure is fed to the Pc3 port via the shuttle valve and holds the swing priority variable orifice to the right...

		As an example, this section explains the right swing and arm-in operation.

		By moving the remote control valve to the right swing side, the pilot pressure oil is fed via the shuttle valve to the control valve Pa3 port and switches to the right swing side.

		At this time, by moving the remote control valve to the arm-in side, the pilot pressure oil is fed via the cushion valve to the control valve Pb5 port and switches the spool to the arm-in side.

		At the same time, the pilot pressure oil from the shuttle valve S port is fed to the control valve Pc3 port to move the swing priority variable orifice to the right side and hold it.

		The discharged oil from hydraulic pump A1 enters the control valve P1 port and is fed from the parallel passage to the swing spool.Switching the spool lets the oil flow into the swing motor B port and carries out the swing operation.

		The discharged oil from hydraulic pump A2 enters the control valve P2 port, is fed from the parallel passage to the arm (2) spoo...

		When the right swing and arm-in operations are carried out at the same time, the swing priority variable orifice on the control valve P1 port parallel passage moves and narrows, so the pressure is boosted to secure the swing force for pressing digging.

		1

		Swing motor

		10

		Remote control valve (arm, swing)

		19

		Arm load hold valve check

		2

		Arm (in)

		11

		Lever lock

		20

		Regeneration release valve

		3

		Arm (out)

		12

		Swing brake

		21

		Control valve

		4

		Right swing

		13

		5-stack solenoid valve

		22

		Swing priority variable orifice

		5

		Left swing

		14

		Console lever lock switch

		23

		Arm (2)

		6

		Cushion valve

		15

		Arm cylinder

		24

		Upper side pilot pressure sensor

		7

		Swing pilot pressure sensor

		16

		Arm (1)

		25

		Hydraulic pump

		8

		Shuttle valve

		17

		Swing

		26

		Check

		9

		Computer A

		18

		Arm load hold valve spool

		27

		Oil cooler

	Swing Circuits

		Suctions in the oil from the make-up line in order to prevent cavitation when swing stops.

		As an example, this section explains the brake circuit operation after the end of a right swing operation.

		When the remote control valve is returned to neutral from a right swing operation, the pilot pressure oil is cut off and the control valve swing spool returns to neutral.

		The pressurized oil fed to the swing motor B port from the control valve A3 port is cut. At the same time, the destination locat...

		When the swing is stopped, the swing motor continues to rotate for a while due to inertial force. In order to make up the shortf...

		1

		Swing motor

		9

		Lever lock

		2

		Cushion valve

		10

		Swing brake

		3

		Right swing

		11

		5-stack solenoid valve

		4

		Left swing

		12

		Console lever lock switch

		5

		Swing pilot pressure sensor

		13

		Computer A

		6

		Remote control valve (arm, swing)

		14

		Control valve

		7

		Hydraulic pump

		15

		Oil cooler

		8

		Check

		16

		Upper side pilot pressure sensor

	Swing Circuits

		When the swing lever is in neutral, swing parking works and is held at 100%.

		When there is a swing lever or attachment operation, swing parking is released.

		Swing parking works about five seconds after the swing lever is put into neutral.

		When an attachment operation is stopped, if there is no swing operation, the swing parking circuit works about one second later.

		When the engine is stopped, swing parking works.

		When the key is switched ON, the swing brake solenoid valve is switched by the electrical signal from the computer A.

		The swing motor P port oil goes from the 5-stack solenoid valve C2 port through the swing brake solenoid, and returns to the hydraulic oil tank to hold the swing parking brake.

		1

		Swing motor

		9

		Lever lock

		2

		Cushion valve

		10

		Swing brake

		3

		Right swing

		11

		5-stack solenoid valve

		4

		Left swing

		12

		Console lever lock switch

		5

		Swing pilot pressure sensor

		13

		Computer A

		6

		Remote control valve (arm, swing)

		14

		Control valve

		7

		Check

		15

		Upper side pilot pressure sensor

		8

		Oil cooler

		16

		Hydraulic pump

	Swing Circuits

		When the engine is started and the swing lever is in neutral, the swing brake solenoid comes ON (24 V input), the pressure to the swing motor P port is cut, and the swing parking brake works.

		When the lever operation raises the reading to 0.5 MPa or higher at the pressure sensor in the swing pilot line, the output from...

		As an example, this section explains the right swing operation.

		By carrying out the right swing operation on the remote control valve, the pilot pressure oil is fed to the control valve Pa3 port via the shuttle valve and switches the swing spool to the right swing side.

		At the same time, the computer A detects the swing pilot pressure sensor signal, judges that there is a swing operation, the ele...

		The discharged oil from hydraulic pump A1 enters the control valve P1 port and is fed from the parallel passage to the swing spool. Switching the spool lets the oil flow into the swing motor B port and carries out the swing operation.

		The pressurized oil from the swing motor A port goes through the swing spool and returns to the hydraulic oil tank.

		When this is followed by an attachment operation, the pilot pressure is detected by the control valve PA port pressure sensor and the swing parking brake continues to be released.

		After the swing operation ends, if about 5 seconds pass with no upper side operation, the swing brake solenoid valve output from the computer A comes ON and the swing parking brake works again.

		After the swing ends, if this is followed by an upper side operation or there is an upper side operation within about 5 seconds, when about 1 second passes after the end of the upper side operation, the swing parking brake works again.

		The swing parking brake is also released for upper side only operations and when about 1 second passes after the end of the upper side operation, the swing parking brake works again.

		Key switch

		Swing pilot pressure sensor

		Upper side pilot pressure sensor

		Swing brake solenoid valve

		Swing motor mechanical brake

		OFF

		0 MPa

		0 MPa

		OFF

		ON

		ON

		0 MPa

		0 MPa

		ON

		ON

		ON

		0.5 MPa min.

		0 MPa

		OFF

		OFF

		ON

		0 MPa

		0.5 MPa min.

		OFF

		OFF

		ON

		0.5 MPa min.

		0.5 MPa min.

		OFF

		OFF

		Pilot pressure sensor judgement standard

		When the pressure goes above 0.5 MPa, the system judges that an operation is underway.

		When the pressure goes below 0.3 MPa, the system judges that the operation has ended.

		1

		Swing motor

		10

		5-stack solenoid valve

		2

		Cushion valve

		11

		Console lever lock switch

		3

		Right swing

		12

		Computer A

		4

		Left swing

		13

		Control valve

		5

		Swing pilot pressure sensor

		14

		Upper side pilot pressure sensor

		6

		Remote control valve (arm, swing)

		15

		Hydraulic pump

		7

		Swing

		16

		Check

		8

		Lever lock

		17

		Oil cooler

		9

		Swing brake

	Option Circuit

		The main control valve has an option section as standard so that it can support a breaker, crusher or other special attachment.

		By operating the option remote control valve to the breaker side, the pilot pressure oil is fed to the control valve Pa2 port and switches the option spool.

		The discharged oil from hydraulic pump A1 is fed from the control valve P1 port through the parallel passage and fed to the option spool. Switching the spool lets the oil flow from the relief valve A port through the B port and into the breaker.

		The breaker set pressure is set by this relief valve.

		At this time, the option pilot pressure sensor signal is detected, the pump P1 flow control proportional valve is controlled by the output signals from the computer A to adjust the discharge flow.

		The return oil from the breaker goes through the manifold and returns to the hydraulic oil tank.

		Because the breaker usage flow can be set to five levels on the service support screen of the monitor display with the ON signal from the breaker switch in the cab, the optimum usage flow can be selected.

		1

		Control valve

		12

		Console lever lock switch

		2

		Manifold

		13

		Lever lock

		3

		Relief valve

		14

		5 stack solenoid valve

		4

		Breaker

		15

		P1 pressure sensor

		5

		Travel pilot pressure sensor

		16

		P2 pressure sensor

		6

		Upper side pilot pressure sensor

		17

		N1 negative control pressure sensor

		7

		Computer A

		18

		N2 negative control pressure sensor

		8

		Monitor display

		19

		P1 flow control proportional valve

		9

		Breaker switch

		20

		Hydraulic pump

		10

		Option remote control valve

		21

		Check

		11

		Option pilot pressure switch

		22

		Oil cooler

	Option Circuit

		As an example, this section explains the case in which the hydraulic fork attachment is used.

		By operating the option remote control valve to the fork close side, the pilot pressure oil is fed to the control valve Pa2 port and switches the option spool to the close side.

		The discharged oil from hydraulic pump A1 enters the control valve P1 port, is fed from the parallel passage to the option spool, flows into the hydraulic fork because of the option spool switching and operates to the close side.

		The return oil from the hydraulic fork goes through the option spool and returns to the hydraulic oil tank.

		1

		Control valve

		8

		5-stack solenoid valve

		2

		Hydraulic fork

		9

		Console lever lock switch

		3

		Travel pilot pressure sensor

		10

		Hydraulic pump

		4

		Upper side pilot pressure sensor

		11

		Option remote control valve

		5

		Monitor display

		12

		Option pilot pressure switch

		6

		Computer A

		13

		Check

		7

		Lever lock

		14

		Oil cooler

	Option Circuit

		It is possible to set the flow for the breaker, crusher, or other special attachment application by just operating a switch in the cab. Maximum of 5 applications

		When the switch in the cab is flipped to the breaker side, the ON signal (24 V) is output from the computer A to the option switch solenoid valve to switch the valve.

		The pilot pressure oil flows from the option switch solenoid valve B1 port to the A1 port and is fed to the 3-direction valve PP port and shut-off valve PP port and each valve is switched.

		Always switch the 2-speed select switch to the 1-speed side.

		By operating the option remote control valve to the breaker side, the pilot pressure oil is fed to the control valve Pa2 port and switches the option spool.

		The discharged oil from hydraulic pump A1 is fed from the control valve P1 port through the parallel passage and fed to the option spool. Switching the spool lets the oil flow from the shut-off valve A port through the B port and into the breaker.

		The breaker set pressure is set by the relief valve into the shut-off valve.

		At this time, the option pilot pressure sensor signal is detected, the pump P1 flow control proportional valve is controlled by the output signals from the computer A to adjust the discharge flow.

		The return oil from the breaker returns from the 3-direction valve A1 port through the T1 port and to the hydraulic oil tank.

		Because the breaker usage flow can be set to five levels on the service support screen of the monitor display, the optimum usage flow can be selected.

		1

		Control valve

		12

		Lever lock

		2

		3-direction valve

		13

		5-stack solenoid valve

		3

		Shut-off valve

		14

		Horsepower control proportional valve

		4

		Breaker

		15

		P1 pressure sensor

		5

		Option remote control valve

		16

		P2 pressure sensor

		6

		Option pilot pressure switch

		17

		N1 negative control pressure sensor

		7

		Compatible circuit switch

		18

		N2 negative control pressure sensor

		8

		Computer A

		19

		P1 flow control proportional valve

		9

		Monitor display

		20

		Hydraulic pump

		10

		Option switchover solenoid valve

		21

		Check

		11

		Console lever lock switch

		22

		Oil cooler

	Option Circuit

		It is possible to switch the circuit between the breaker and the crusher by just operating the switch in the cab.

		When the 2nd speed marge select switch in the cab is flipped to the 2nd speed merge side, the ON signal (24 V) is output from the computer A to the 2nd speed merge solenoid valve to switch the valve.

		When the compatible circuit switch is flipped to the pulverizer side, the pulverizer circuit is formed without outputting a signal from the computer A to the option switch solenoid valve and without switching the valve.

		At this time, the pilot signal does not go to the 3-direction valve or to the shut-off valve and the 3-derection valve forms the A �� B circuit.

		By operating the option remote control valve to the pulverizer side, the pilot pressure oil is fed to the control valve Pa2 port and switches the option spool.

		At the same time, the pilot pressure oil flows from the 2nd speed merge solenoid valve B2 port to the A2 port and is fed to the control valve Pcc port and the control valve neutral cut valve is switched.

		The discharged oil from hydraulic pump A2 enters the control valve P2 port and goes through the center bypass passage and since ...

		The discharged oil from hydraulic pump A1 is fed from the control valve P1 port through the parallel passage and fed to the option spool. Switching the spool lets the oil flow from the shut-off valve A port through the B port and into the pulverizer.

		At this time, the option pilot pressure sensor signal is detected, the pump P1 flow control proportional valve is controlled by the output signals from the computer A to adjust the discharge flow.

		The return oil from the pulverizer returns from the 3-derection valve A port through the B port and the option spool and returns to the hydraulic oil tank.

		Because the pulverizer usage flow can be set to five levels on the service support screen of the monitor display, the optimum usage flow can be selected.

		1

		3-direction valve

		10

		Monitor display

		19

		5-stack solenoid valve

		2

		Shut-off valve

		11

		computer A

		20

		Console lever lock switch

		3

		Pulverizer

		12

		Compatible circuit switch

		21

		Horsepower control proportional valve

		4

		Option switchover solenoid valve

		13

		2nd speed merge select switch

		22

		P1 pressure sensor

		5

		2-way merge solenoid valve

		14

		Control valve

		23

		P2 pressure sensor

		6

		Option remote control valve

		15

		Neutral cut valve

		24

		N1 negative control pressure sensor

		7

		Check

		16

		Travel pilot pressure sensor

		25

		N2 negative control pressure sensor

		8

		Oil cooler

		17

		Upper side pilot pressure sensor

		26

		P1 flow control proportional valve

		9

		Option pilot pressure switch

		18

		Lever lock

		27

		Hydraulic pump

	Option Circuit

		Option valve can be added to the top section of the control valve and a second option line can be installed easily.

		As an example, this section explains the case in which the hydraulic rotation fork attachment is used.

		By operating the 2nd option remote control valve to the right swing side, the pilot pressure oil is fed to the control valve Par2 port.

		The 4th hydraulic pump OUT discharged oil is fed to the control valve Pr port, goes through the 2nd option spool and flows to the hydraulic rotation fork to operate to the right swing side.

		The return oil from the hydraulic rotation fork goes through the 2nd option spool and returns to the hydraulic oil tank.

		The oil in the 2nd option drain line returns to the hydraulic oil tank without going through the control valve.

		1

		Control valve

		9

		Oil cooler

		2

		Travel pilot pressure sensor

		10

		Hydraulic rotation fork

		3

		Upper side pilot pressure sensor

		11

		2nd option pilot pressure switch

		4

		Lever lock

		12

		Monitor display

		5

		5-stack solenoid valve

		13

		Computer A

		6

		Console lever lock switch

		14

		4th pump

		7

		2nd option remote control valve

		15

		Hydraulic pump

		8

		Check

	Option circuits

62_Hydraulic.pdf

	Hydraulic pumps

	Hydraulics Components

	Travel motor

	Swing motor

	Main Control Valve

	Remote control valve

	5 soleno�ds bloc

	Cushion valve

	Selector valve (3 way)

	Direction valve

	Shut-off valve

	Cylinders

	HBCV valve

	Manifold (pilot pressure)



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