Takeuchi Hydraulic excavator TB1140 (Serial No. 514400002~). Operator's Manual

FUNCTION

PILOT VALVE (CONTROL LEVER)

The pilot valve is a remote-controlled valve with a reduc-

ing valve system used to operate the spool in the control

valve. The pilot valve comes with right and left control le-

vers.

The pilot valve casing contains a vertical shaft hole that

incorporates a reducing valve. When the lever is tilted,

the push rod and spring seat are pushed down, chang-

ing the spring force of the secondary pressure.

The casing contains the oil inlet port P (the primary pres-

sure) and the tank port T. The secondary pressure corre-

sponding to the changes in operating angle performed

by the lever (1) can be provided through the output ports

A and B located below the vertical shaft hole. The sec-

ondary pressure functions as the pilot pressure to actu-

ate the spool of the control valve (2).

When the lever (1) is in the neutral position:

The force of the spring (3) that determines the output

pressure (secondary pressure) of the pilot valve is not

conveyed to the spool (4). This causes the spool (4) to be

pushed up by the return spring (5), and the output ports

A and B are connected to the tank port T. This causes the

pressures in the ports A and B to be equal to the pres-

sure in the tank port T.

When the lever (1) is tilted:

When the lever (1) is tilted and the push rod (6) is

pushed, the spool (4) moves downward and the input

port P is connected with the output port A. Then, the oil

from the pilot pump flows into the output port A, generat-

ing a pressure.

PILOT VALVE (CONTROL LEVER)

3K2AS00

FUNCTION

PILOT VALVE (CONTROL LEVER)

When the lever (1) is kept at a certain position:

When the pressure in the output port A increases to the

level equivalent to the force of the spring (3) set by the

inclination of the lever (1), the hydraulic pressure is bal-

anced with the spring force. When the pressure in the

output port A becomes higher than the set spring force,

the output port A is disconnected from the input port P

while it is now connected with the tank port T. When the

pressure in the output port A becomes lower than the set

spring force, the output port A is connected with the input

port P, while it is now disconnected from the tank port T.

Thus, the secondary pressure is always kept constant.

PILOT VALVE (CONTROL LEVER)

3K2AS00

FUNCTION

PILOT VALVE (SWING)

The pilot valve is a remote-controlled valve with a reduc-

ing valve system used to operate the spool in the control

valve. The pilot valve (swing) is located on the left side of

the driver’s seat on the floor.

The pilot valve casing (1) contains a vertical shaft hole

that incorporates a reducing valve (2). When the cam (3)

is tilted, the push rod (4) and spring seat (5) are pushed

down, which changes the pressure of the secondary

pressure spring (6).

The casing (1) contains the oil inlet port P (primary pres-

sure) and the tank port T. The secondary pressure which

corresponds to changes in operating angle produced

using the cam (3) can be provided through the output

3K3AQ01Z

ports A and B located below the vertical shaft hole. The

secondary pressure functions as the pilot pressure to ac-

tivate the spool of the control valve.

When the cam (3) is in the neutral position:

The force of the spring (6) that determines the output

pressure (secondary pressure) of the pilot valve is not

conveyed to the spool (7). This causes the spool (7) to be

pushed up by the return spring (8) and spring sheet (5),

and the output ports A and B are connected to the tank

port T, which makes the pressures in the ports A and B

be equal to the pressure in the tank port T.

When the cam (3) is tilted:

When the cam (3) is tilted and the push rod (4) is pushed,

the spring sheet (5) and spool (7) move downward, and

the input port P is connected to the output port A. The oil

from the pilot pump then flows into the output port A to

generate a pressure.

3K3AQ03Z

PILOT VALVE (SWING)

3K3AQ00

FUNCTION

PILOT VALVE (SWING)

When the cam (3) is kept at a certain position:

When the pressure in the output port A increases to a lev-

el equivalent to the force of the spring (6) set by the incli-

nation of the cam (3), the hydraulic pressure is balanced

with the spring force. When the pressure in the output

port A becomes higher than the set spring force, the out-

put port A is disconnected from the input port P and then

becomes connected to the tank port T. When the pres-

sure in the output port A drops below than the set spring

force, the output port A becomes connected to the input

port P and it is then disconnected from the tank port T.

The secondary pressure is thus always kept constant.

3K3AQ04Z

PILOT VALVE (SWING)

3K3AQ00

FUNCTION

PILOT VALVE (BLADE)

The pilot valve is a remote-controlled valve with a reduc-

ing valve system used to operate the spool in the control

valve. The pilot valve (blade) is located on the right side

of the driver’s seat on the floor.

The pilot valve casing (1) contains vertical shaft holes

that incorporatea reducing valves (2). When the cam (3)

is tilted, the push rod (4) and spring seat (5) are pushed

down, which changes the pressure of the secondary

pressure spring (6).

The casing (1) contains the oil inlet port P (primary pres-

sure) and the tank port T. The secondary pressure which

corresponds to changes in operating angle produced

using the cam (3) can be provided through the output

3K3AQ01Z

ports A and B located below the vertical shaft hole. The

secondary pressure functions as the pilot pressure to ac-

tivate the spool of the control valve.

When the cam (3) is in the neutral position:

The force of the spring (6) that determines the output

pressure (secondary pressure) of the pilot valve is not

conveyed to the spool (7). This causes the spool (7) to be

pushed up by the return spring (8) and spring sheet (5),

and the output ports A and B are connected to the tank

port T, which makes the pressures in the ports A and B

be equal to the pressure in the tank port T.

When the cam (3) is tilted:

When the cam (3) is tilted and the push rod (4) is pushed,

the spring sheet (5) and spool (7) move downward, and

the input port P is connected to the output port A. The oil

from the pilot pump then flows into the output port A to

generate a pressure.

3K3AQ03Z

PILOT VALVE (BLADE)

3K3AQ01

FUNCTION

PILOT VALVE (BLADE)

When the cam (3) is kept at a certain position:

When the pressure in the output port A increases to a lev-

el equivalent to the force of the spring (6) set by the incli-

nation of the cam (3), the hydraulic pressure is balanced

with the spring force. When the pressure in the output

port A becomes higher than the set spring force, the out-

put port A is disconnected from the input port P and then

becomes connected to the tank port T. When the pres-

sure in the output port A drops below than the set spring

force, the output port A becomes connected to the input

port P and it is then disconnected from the tank port T.

The secondary pressure is thus always kept constant.

3K3AQ04Z

PILOT VALVE (BLADE)

3K3AQ01

FUNCTION

PILOT VALVE (TRAVEL)

The pilot valve is a remote-controlled valve with a reduc-

ing valve system used to operate the spool in the control

valve. The pilot valve (travel) is located the below the

travel lever near the driver’s seat.

The pilot valve casing (1) contains vertical shaft holes

that incorporate reducing valves (2). When the cam (3) is

tilted, the push rod (4) and spring seat (5) are pushed

down, which changes the pressure of the secondary

pressure spring (6).

The casing (1) contains the oil inlet port P (primary pres-

sure) and the tank port T. The secondary pressure which

corresponds to changes in operating angle produced

using the cam (3) can be provided through the output

3K3AQ05Z

ports A and B located below the vertical shaft hole. The

secondary pressure functions as the pilot pressure to ac-

tivate the spool of the control valve.

This pilot valve also comes equipped with a damping

function to prevent hunting oscillation resulting from the

supply of oil lagging behind from occurring during sud-

den operation.

When the cam (3) is in the neutral position:

The force of the spring (6) that determines the output

pressure (secondary pressure) of the pilot valve is not

conveyed to the spool (7). This causes the spool (7) to be

pushed up by the return spring (8) and spring sheet (5),

and the output ports A and B are connected to the tank

port T, which makes the pressures in the ports A and B

be equal to the pressure in the tank port T.

When the cam (3) is tilted:

When the cam (3) is tilted and the push rod (4) is pushed,

the spring sheet (5) and spool (7) move downward, and

the input port P is connected to the output port A. The oil

from the pilot pump then flows into the output port A to

generate a pressure.

3K3AQ07Z

PILOT VALVE (TRAVEL)

3K3AQ02

FUNCTION

PILOT VALVE (TRAVEL)

When the cam (3) is kept at a certain position:

When the pressure in the output port A increases to a lev-

el equivalent to the force of the spring (6) set by the incli-

nation of the cam (3), the hydraulic pressure is balanced

with the spring force. When the pressure in the output

port A becomes higher than the set spring force, the out-

put port A is disconnected from the input port P and then

becomes connected to the tank port T. When the pres-

sure in the output port A drops below than the set spring

force, the output port A becomes connected to the input

port P and it is then disconnected from the tank port T.

The secondary pressure is thus always kept constant.

3K3AQ08Z

Damping function

The damping function prevents hunting oscillation from

occurring due to the supply of oil lagging behind during

sudden operation of the pilot valve.

When the cam (3) is tilted, which pushes the push rod (4)

on the port A side, the spool (7) and piston (9) move

4-1

downward. At this time, the oil in the piston chamber (10)

is discharged from the orifice (11) in the piston (9), which

generates a pressure. This damping pressure prevents

the push rod (4) from moving suddenly.

Meanwhile, the push rods (4-1) on the port B side are

moved upward by the spring (12) via the piston (13).

The ball (14) is pushed up, causing the oil in the tank

chamber to flow into the piston chamber (15), which pre-

vents the piston chamber (15) from experiencing a neg-

ative pressure. The oil outside of the piston chamber re-

turns to the tank through the tank channel in the top of the

casing.

3K3AQ09Z

PILOT VALVE (TRAVEL)

3K3AQ02

FUNCTION

PILOT VALVE (TRAVEL)

If the cam (3) is tilted all the way down and then tilted in

the opposite direction, the push rods (4-1) on the port B

side are pushed down, and the piston (13) is moved

downward.

At this time, the oil in the piston chamber (15) is dis-

charged from the orifice (16) in the piston, which gener-

ates a pressure.

4-1

Meanwhile, the push rod (4) on the port A side is moved

upward by the spring (17) via the piston (9).

The ball (14) is pushed up, causing the oil in the tank

channel to flow into the piston chamber (10), which pre-

vents the piston chamber (10) from experiencing a neg-

ative pressure. The oil outside of the piston chamber re-

turns to the tank from the tank channel connected to the

tank in the top of the casing.

The pilot valve is formed in this way so that the damping

function works to prevent hunting oscillation no matter

the position from which the handle is operated.

3K3AQ10Z

PILOT VALVE (TRAVEL)

3K3AQ02

FUNCTION

PROPORTIONAL CONTROL SOLENOID VALVE

The proportional lever (2) and proportional amplifier (3)

of the pilot valve (1) control the driving current that flows

to the proportional control solenoid valve (4), which con-

trols the pilot pressure of the control valve (5) (auxiliary

section) whereby the flow rate of the auxiliary line piping

changes.

The proportional control solenoid valve controls the sec-

ondary pressure using the built-in proportional pressure-

educing valve. The secondary pressure generated cor-

responds to the changes in current because of the force

used to generate the secondary pressure being applied

to the solenoid in accordance with the amount of current

flowing through the coil.

3K4AQ01Z

When current flows through the solenoid, a thrust force

proportional to the current is generated and moves the

spool (6) so that the oil supplied from the port P is intro-

duced into the port A on the secondary pressure side,

S=A1-B1

which increases the pressure Pa of the port A.

The pressure Pa acts on the differential area S between

B1 A1

the cross section A1 and cross section B1 of the spool

(6), and the spool (6) is pushed to the solenoid side by

Fks

the oil pressure, Pa × s. The spool (6) stops at the posi-

Paxs

tion where the sum of the oil pressure, Pa × s, and the

force, Fk, exerted by the springs (7) is balanced with the

thrust force, Fs, generated by the solenoid. The weight,

Fks, of the spring (8) used for fine adjustment of the sec-

Paxs

Fks

ondary pressure acts in the direction (left) of assistance

3K4AQ02Z

of the thrust force from the solenoid.

When the thrust force is greater than a set value, the

spool (6) is moved to the left, which connects the port P

(supply side) and the port A (secondary side) together

through the notch (9).

3K4AQ03Z

When the thrust force is lower than a set value, the spool

(6) is moved to the right, which connects the port A (sec-

ondary side) and the port T (tank side) together through

the notch (10).

The opening areas of the notch (9) on the supply side

and the notch (10) on the discharge side are thus con-

trolled by the movement of the spool (6), and a second-

ary (pilot) pressure can be provided that corresponds to

the thrust force generated by the solenoid.

3K4AQ04Z

PROPORTIONAL CONTROL SOLENOID VALVE

3K4AQ00

FUNCTION

EMERGENCY SHUT-OFF VALVE

The emergency shut-off valve is used to keep the boom

or arm from falling to maintain safety by blocking and

shutting off the oil from the cylinder head side even if the

hydraulic hose should become damaged while the boom

or arm is being raised.

The pressure oil of the hydraulic pump pushes up the

check valve (1) from the port V2 while the boom or arm is

being raised and flows from the port C2 to the boom or

arm cylinder.

PIL

3K5AQ01Z

The pilot pressure is introduced into the port PIL from the

pilot valve (2) while the boom or arm is being lowered.

The pilot pressure moves the spool (3) to the left side

from the port PIL. The return oil from the cylinder flows

from the port C2 through the channels in the spool (3)

and check valve (1) to the tank channel from the port V2.

PIL

3K5AQ02Z

The channels in the check valve (1) and spool (3) are

blocked if the hydraulic hose becomes damaged, which

shuts off the oil on the cylinder head side to prevent the

boom and arm from falling even if either tries to go down.

PIL

3K5AQ03Z

EMERGENCY SHUT-OFF VALVE

3K5AQ00

FUNCTION

SOLENOID VALVE

This valve switches circuit connections by moving the

spool using magnets and supplies the pilot pressure to

the pilot valve and 2nd-speed travel switch.

The pilot pressure is kept constant with the relief valve.

Solenoid valve

When the solenoid is not energized:

The oil in the port P (pump side) is blocked by the spool

(1).

The oil flows through the port A (on the pilot circuit side

of the pilot valve or 2nd-speed travel switch) and port T

(on the tank side), which results in the pressure of the

downstream pilot circuit being the same as the tank pres-

sure.

When the solenoid is energized:

A magnetic field is generated around the coil that causes

the push rod to be pulled downward and the spool (1) to

be pushed down. This causes the oil in the port P to flow

to the port A, and the pressure is transmitted to the lower

pilot circuit.

Check valve

The IN port is connected to the pump and the OUT port

to the accumulator.

This works to prevent a backward flow of oil from the OUT

port to the IN port side should the pressure in the IN port

become a negative pressure.

1 IN

2 OUT

SOLENOID VALVE

3K6AS00

FUNCTION

SHOCKLESS VALVE

This valve controls the flow rate used to operate the con-

trol valve spool from the pilot valve and keeps it at a con-

stant rate when the boom is lowered and works to pre-

vent the machine from vibrating so that the boom does

not drop suddenly.

Port A side Port B side

The hydraulic oil supplied from port A passes through the

orifice (1) and flows into the port B through a side hole in

the plunger (2).

The pressure P1 flows into chamber C on the left side of

the plunger (2) before closing and the pressure P2 flows

into chamber D on the right side after closing. Because

the areas a and b of the plunger (2) affected by pressure

are the same size, the pressure differential PC between

P1 and P2 is determined by the force of the spring (3).

When the pressure in port A increases causing the flow

rate through the orifice (1) to increase, the pressure dif-

ferential between P1 and P2 rises, and the plunger (2)

moves to the right and pushes on the spring (3). When

this occurs, the opening e through which pressure flows

from outside of the valve decreases in size, which acts to

decrease the flow rate for flow from the outside of the

valve.

The opening e is closed and becomes balanced so that

the plunger (2) becomes static until the pressure differ-

ential between P1 and P2 becomes equal to the pressure

differential PC set initially.

In addition, should the reverse occur and the pressure in

the port A decrease causing the flow rate through the or-

ifice (1) to decrease, the pressure differential between P1

and P2 drops, and the plunger (2) moves to the left of the

spring (3), and the opening e becomes bigger, which en-

ables the hydraulic oil to flow from port A more easily. The

plunger (2) then moves and becomes static until the

pressure differential between P1 and P2 becomes equal

to the pressure differential PC set initially.

That is, if the pressure differential for the port A side and

port B side of the valve is changed, the pressure before

and after the orifice (1) inside the valve becomes con-

stant.

Port B side Port A side

When hydraulic oil is supplied to port B, the hydraulic oil

passes through the orifice (1) and flows into port A. At this

time, due to resistance with regard to allowing passage in

the orifice (1), the relationship in pressure between P1 and

P2 becomes such that P1 < P2, and the plunger (2) moves

to the left side. When this occurs, the circuit for section f

opens, and the hydraulic oil from port B flows through the

side hole in the plunger (2), and the entire volume flows into

port A.

If the hydraulic oil is cut off, the plunger (2) returns to the

center position using the force of the spring.

SHOCKLESS VALVE

3K9AS00

FUNCTION

CYLINDERS

The pressure oil flowing alternately in through the outlet

and inlet on both sides (head and rod sides) of the piston

acts on the piston and the force produced causes the

piston to move back and forth.

For those cylinders with a cushion mechanism, the shock

resulting from the piston colliding with the cover at the

stroke end is dampened by the mechanism.

Cushion mechanism

When the piston (1) approaches the stroke end and ap-

pears likely to bump into the cover (2), the cushion bear-

ing (3) that is moving ahead of the piston enters the cush-

ion seal (4). As this shuts off the return passage for the

hydraulic oil on the back of the piston, the oil is expelled

only from the throttle hole or the groove provided in the

cushion bearing (3). This causes the piston (1) backpres-

sure to increase, slowing the piston speed.

CYLINDERS

3L0AS00

FUNCTION

TRAVEL MOTOR 3

TRAVEL MOTOR

This section includes descriptions of the hydraulic motor,

which is driven by hydraulics, the brake valve, the relief

valve, the 2nd-speed switching mechanism, the parking

brake, and the reduction gears.

Hydraulic motor

The hydraulic motor is an axial piston motor with a

swashplate design. It converts the force of the pressure

oil transmitted from the pump into rotational movement.

The cylinder block (104) of the hydraulic motor is formed

of pistons (105), and its end surface comes in contact

with the valve plate (109), which contains the two cres-

cent-shaped ports B and C. The cylinder block (104) can

be rotated and is connected to the shaft (102) via the

spline.

The pressure oil supplied from the pressure oil pump is

injected into the cylinder block (104) through the valve

plate (109). At this time, the pressure oil is injected only

into one side (the port B side) connected to the bottom

dead center during a stroke of the pistons (105).

The pressure oil pushes on each piston (105) to generate

a force, F (=P×A), which acts on the angled surface of

the swashplate (103). The force F is split into two force

components F2 and F3 through the angle θ of the angled

surface, and the radial component F3 of these force

components produces a torque

(=F3×ri). The total

torque T (=∑(F3×ri)) of each piston (105) is used as the

rotational force that turns the hydraulic motor. This rota-

tional force turns the cylinder block (104) and the shaft

(102) via the pistons (105).

TRAVEL MOTOR

3M0AS00

FUNCTION

TRAVEL MOTOR 3

Brake valve

During normal operation

When pressure oil is supplied from port (A), the pressure

oil opens the valve (327), causing the oil to flow into port

the hydraulic motor.

Simultaneously, the pressure oil enters the chamber (a)

from the orifice (329) and operates on the end surface of

the spool (323) to generate a force that causes the spool

(323), which is in a neutral position, to slide to the left by

the force of the spring (328).

Once the spool (323) has been slid, a gap (passage) is

formed between the spool (323) and the rear flange by

the groove in the spool.

This passage enables the return oil to return to the tank

side through the port (D) in the passage on the return

side of the hydraulic motor and through the port (B),

which enables the hydraulic motor to turn.

In addition, the pressure oil enters the port (E) due to the

sliding of the spool (323). The pressure oil that entered

the port (E) moves the piston of the parking brake and re-

leases the parking break.

For pressure oil supplied from the port (B), the spool and

valve move horizontally in reverse and rotate in reverse.

TRAVEL MOTOR

3M0AS00

FUNCTION

TRAVEL MOTOR

Stop operation (Braking operation)

When the supply of oil from the port (A) stops during trav-

el operation, the oil pressure pushing against the spool

(323) is eliminated, and the spool (323) that was slid to

the left attempts to return to the neutral position through

the washer (325) using the force from the spring (328).

At this time, the oil in the chamber (a) attempts to flow to

the port (A) side through the orifice (329), but a back

pressure is generated due to effects of the opening cre-

ated in the orifice (329), which works to control the return

speed of the spool (323).

Simultaneously, the hydraulic motor attempts to continue

rotating due to the influence of inertia, even after the sup-

ply of oil has stopped, which causes the return oil for the

hydraulic motor to attempt to return to the port (B) side

from the port (D) and through the gap (passage) be-

tween the spool groove and the rear flange.

Once the spool (323) returns all the way to the neutral po-

sition, the passage on the hydraulic motor return side is

completely shut off by the spool (323), causing the hy-

draulic motor to stop.

During operation, this brake valve controls the sliding

speed of the spool (323) and shape of the spool groove

used to close the passage on the hydraulic motor return

side, which enables the hydraulic motor to be smoothly

brought to a stop while it tries to rotate due to the inertial

force produced by the generated backpressure.

Meanwhile, when the hydraulic motor attempts to stop

due to braking, inertia causes the pump to continue ro-

tating and operating to attempt to absorb oil even after

the supply of pressure oil is shut off.

However, the passage on the suction side is blocked off

by the spool (323) so that the oil cannot be refilled, which

causes cavitation to begin to form.

At this time, the valve (327) operates under a slight neg-

ative pressure to open the oil pressure circuit between

the circuit on the port (A) side and the port (C) of the mo-

tor suction vent, which prevents cavitation from forming

in the hydraulic motor.

If the pressure oil is supplied from the port (B), the move-

ment of each of the aforementioned parts becomes sym-

metrical, which causes the motor to stop.

TRAVEL MOTOR

3M0AS00

FUNCTION

TRAVEL MOTOR

Function to prevent out-of-control operation

If the hydraulic motor begins rotating due to an external

force, the machine may begin operating uncontrollably

(run out of control) during operation at normal tempera-

ture. This could occur when the driver is trying to go

down a steep incline, for example.

An explanation of the mechanism used to prevent uncon-

trollable operation (out-of-control operation) is provided

here.

The hydraulic motor begins rotating due to an external

force during operation at normal temperature. The pres-

sure in the port (A) or port (B) supplying operating oil

drops.

When the pressure rises toward the level at which the

machine operates uncontrollably, the spool (323) begins

moving toward the neutral position.

Tthe size of the area of the passage for the oil from the

port (D) on the hydraulic motor outlet port side to the port

(B) decreases along with the travel distance of the spool

(323).

This limits the flow rate for the operating oil discharged

from the port (D) to the port (B).

The pressure (backpressure) in the port (D) increases at

the same time.

This controls the flow rate and pressure of the hydraulic

motor outlet port, which works to prevent uncontrolled

machine operation.

TRAVEL MOTOR

3M0AS00

FUNCTION

TRAVEL MOTOR 3

Explanation of relief valve operation

At startup

The pressure oil supplied from the pump flows from port

(A) to port (C).

Port (C) is connected to the hydraulic motor, and the

pressure oil that flows into port (C) exerts a rotational

force on the hydraulic motor.

At this time, in the relief valve (A), the valve (202a) does

not open through operation with the pressure oil.

In the relief valve (B), the valve (202b) is opened by the

pressure oil from port (C) when a pressure exceeding a

given level is exerted, and the pressure oil flows into port

(D).

The pressure oil from port (C) flows through the opening

(e) in the valve (202b), the opening (f) in the sleeve

(203b), and the orifice (384) into the chamber (y).

This pressure oil that flowed into the chamber (y) causes

the piston (381) to move to the stroke end in the direction

of the arrow.

When the piston (381) reaches the stroke end, the pres-

sure between the opening (e) in the valve (202b) and the

opening (f) in the sleeve (203b) increases.

The release pressure in the relief valve (B) increases to a

value about the system pressure of the shovel due to the

increase in pressure of the pressure oil, which causes

the valve (202b) to become closed.

The pressure of the port (C) increases and exerts a rota-

tional force on the motor due to the operation of the relief

Relief valve A

valve (A) and relief valve (B).

Relief valve B

TRAVEL MOTOR

3M0AS00

FUNCTION

TRAVEL MOTOR 3

Pressure conditions in port (C) during the operation de-

scribed above

However, depending on the condition of the machine im-

mediately before it stops, the valve (202b) of the relief

valve (B) may not open if the piston (381) has reached

the stroke end.

The resultant pressure acting on the port (C) in this case

is described below.

1 Pressure

2 Release of relief valve B

3 Time

As described above, the pressure of the port (C) at start

up varies depending on the position of the piston (381).

The following is an example substituting the relief valve

(B) for the relief valve (A) in the above description of op-

erating principles for when the pressure oil supplied from

the pump flows from the port (B) to the port (D).

3M0AS07

1 Pressure

3 Time

TRAVEL MOTOR

3M0AS00

FUNCTION

TRAVEL MOTOR

During shutdown

When the supply of oil to the port (A) for the hydraulic mo-

tor, which rotates from the supply of pressure oil from the

port (A) to the port (C), is depleted, the counterbalance

valve returns to the neutral position.

When the counterbalance valve returns to neutral, the

port (D) on the outlet port side is shut off, causing the

pressure within the port (D) to increase due to the rota-

tion of the hydraulic motor according to the amount of in-

ertia.

The pressure oil inside the port (D) flows through the

opening (c) in the valve (202a), the sleeve (203a), and

the orifice (384) and into the chamber (x) in the relief

valve (A).

The pressure oil that flowed into the chamber (x) causes

the piston (381) to move to the stroke end in the direction

of the arrow.

The pressure in the chamber (x) does not increase while

the piston (381) is being moved.

This causes the valve (202a) of the relief valve (A) to be

pushed open by the pressure oil in the port (D), resulting

in the pressure oil from the port (D) flowing into the port

The relief valve (A) operates to control the pressure in the

port (D) and supply oil to the port (C), which works to pre-

vent cavitation.

When the piston (381) reaches the stroke end, the pres-

sure between the chamber (x) and the opening (b) in the

Relief valve A

valve (202a) and opening (c) in the sleeve (203a) in-

Relief valve B

creases, causing the valve (202a) to close.

In this case, the relief valve (A) works to relieve the sys-

tem pressure and stop the hydraulic motor.

TRAVEL MOTOR

3M0AS00

FUNCTION

TRAVEL MOTOR 3

Automatic 2-speed switching mechanism

At low speed

If there is no pilot pressure supplied from the port (P), the

valve (363) is pushed upward by the force of the spring

(366) and the pressure oil from the port (A) or port (B).

The pressure oil from (C) is blocked, and the oil from the

chamber (W) is released into the drain (motor case) via

the valve (363).

As a result, the angle of inclination of the swashplate

(103) increases to the maximum angle θ1, which causes

the displacement of the hydraulic motor to be maximized

and rotation to proceed at low speed.

TRAVEL MOTOR

3M0AS00

FUNCTION

TRAVEL MOTOR 3

At high speed

If there is a pilot pressure supplied from the port (P), the

pilot pressure overcomes the force of the spring (366)

and the pressure oil from the port (A) or port (B) and

pushes the valve (363) downward, which causes the

pressure oil from the port (C) to flow into the chamber (W)

via the valve (363).

The piston (161) pushes the swashplate (103) downward

until it makes contact with the surface (X) and held at that

position.

At this time, the swashplate (103) is positioned at the

minimum angle of inclination θ 2, which causes the dis-

placement of the hydraulic motor to be minimized and ro-

tation to proceed at high speed.

TRAVEL MOTOR

3M0AS00

FUNCTION

TRAVEL MOTOR 3

Automatic switching to low speed during high-speed op-

eration

If the size of the load increases during high-speed oper-

ation, the pressure of the pressure oil in port (A) or port

(B) also increases, and when the pressure reaches a

specified value, the pressure overcomes the pilot pres-

sure of the port (P) and pushes the valve (363) upward.

The oil in the chamber (W) is released to the drain (motor

case) via the valve (363).

At this time, the swash plate (103) is pressed against the

surface (Y) and maintains a maximum angle of inclination

of θ1 in low-speed rotation.

TRAVEL MOTOR

3M0AS00

FUNCTION

TRAVEL MOTOR 3

Parking brake

The parking brake works to prevent the hydraulic motor

from rotating due to an external force exerted while the

hydraulic motor is stopped. The parking brake uses a

friction disc braking mechanism and is formed together

with the hydraulic motor as one piece.

The friction disc (115) and the disc (116) of the hydraulic

motor are connected through the spline. The friction disc

(115) and the disc (116) are pressed against the spindle

by the springs (113) via the brake piston (112). The fric-

tion force between these discs generates a braking

torque that prevents the cylinder block (104) from rotat-

ing.

When the pressure oil is introduced into the motor, the

pressure oil flows from the parking brake release port (E)

into the brake piston chamber (F). The oil pressure over-

powers the spring force and moves the brake piston

(112) to the left. This creates a clearance between the

friction disc (115) and the disc (116), which releases the

parking brake function.

When the motor is stopped, the pressure oil from the

parking break release port is blocked, which causes the

springs (113) to generate a parking brake force.

TRAVEL MOTOR

3M0AS00

FUNCTION

TRAVEL MOTOR

Reduction gears

The reduction gears are formed of a 2-stage planetary

gear system that works to slow down the high-speed ro-

tational movement from the hydraulic motor and converts

it to a low-speed, high torque.

The reduction gears of the hydraulic motor are formed of

a 2-stage planetary gear system that works to convert the

high-speed rotational movement from the hydraulic mo-

tor into a low-speed, high torque and use the torque to ro-

tate the hub (1).

The rotational movement of the hydraulic motor axis is

transmitted to the 1st-stage sun gear (3) connected to

the spline in the shaft (2). At this stage, the 1st-stage

planetary gear (4) is meshed with the sun gear (3) and

meshes with the hub (1) to move in orbital motion while

rotating.

The orbital motion rotates the gear (5) affixed to the plan-

etary gears (4) as well as the 2nd-stage sun gear (6) con-

nected to the gear (5).

Input

This rotation is transmitted to the hub (1) (ring gear) via

Output

the 2nd-stage planetary gears (8) affixed to the support

column of the spindle (7) and produces the output rota-

tion of the reduction gears. The rotation is transmitted

from the 1st-stage planetary gears (4).

TRAVEL MOTOR

3M0AS00

FUNCTION

SLEW MOTOR 3

SLEW MOTOR

This section includes descriptions of the hydraulic motor

driven by hydraulics, the relief valve, the make-up valve,

the parking brake, the timer valve, and the reduction

gears.

Hydraulic motor

The cylinder block (1) is formed of pistons (2), and its end

surface comes in contact with the valve plate (3), which

contains two half-moon-shaped ports B and C. The cylin-

der block (1) rotates freely and is connected to the shaft

(4) via the spline. Meanwhile, the swashplate (5) is se-

cured to the housing.

When the high-pressure oil is made to flow into port B, the

pistons (2) push the swashplate (5) with a force F per pis-

ton (2).

F = P x A, P: Pressure, A: Cross-sectional area of piston

The force F used to push the swashplate (5) by the pis-

tons (2) is divided into two components: a force F1 that

pushes against the plate and a force F2 that rotates the

cylinder block (1). The total sum of the components in the

direction of rotation of the high-pressure side piston

works to generate a rotational force in the cylinder block

(1), and the torque is transmitted via the spline to the

shaft (4) to turn it. Conversely, if high-pressure oil is intro-

duced into the port C, the rotation occurs in the direction

opposite that of the above.

3N0AQ01Z

Relief valve

The relief valves are used to set the driving force and

braking force during slew operation of the machine, with

each having main port A, B lines and each being formed

of a circuit in which the relief valve return oil returns to the

main low-pressure line on the opposite side through the

make-up valves. The relief valves also come equipped

with shockless functions that reduce the impact of

shocks generated at the start of acceleration.

The inertial load at motor startup is fairly significant and

causes the oil pressure used for rotation to actually in-

crease. When this pressure reaches the set relief valve

3N0AQ02Z

pressure, the relief valve (6) turns on, and the oil opens

the make-up valve (7) and flows into the port B.

This type of motor starts rotating while activating the relief

valve (6), with the amount of relief oil decreasing to zero

as the number of rotations increases.

This allows shocks to be absorbed during startup.

SLEW MOTOR

3N0AS00

FUNCTION

SLEW MOTOR 3

When the motor stops, the return circuit closes. However,

the motor continues trying to rotate using the inertial en-

ergy, which causes the port B pressure to increase and

the port A to experience a negative pressure in contrast.

When the port B pressure reaches the set value for the

relief valve, the oil acts on the relief valve (6), which caus-

es the make-up valve (7) to open and the oil to flow into

port A.

With the oil flowing into the port A in this way, shocks from

stopping are absorbed while the formation of cavitation

is prevented.

3N0AQ03Z

Structure of the relief valve

Use of a shockless relief valve has the effect of reducing

the impact of shocks, reducing the amount of stress gen-

erated in strengthening support parts, and the like.

3N0AQ04Z

1 Direct-acting differential area relief valve

2 Shockless piston

There are two stages in relief valve operation as listed

below.

1st-stage

At the beginning of operation, the shockless piston (8) is

moved, and a low pressure is maintained within the

spring chamber (9). For this reason, the area of the pop-

pet (10) affected by pressure is the poppet sheet area

(S1). The area affected by pressure is fairly large com-

pared to the area affected by pressure (S1-S2) during

regular relief setting. This allows the relief hydraulic pres-

sure to be maintained at a low value until the shockless

piston (8) finishes being moved.

3N0AQ05Z

SLEW MOTOR

3N0AS00

FUNCTION

SLEW MOTOR 3

2nd-stage

Once the shockless piston

(8) has stopped being

moved, the pressure inside the spring chamber (9) in-

creases and becomes equal to the pressure in front of

and behind the poppet (10). The relief valve is thus acti-

vated by the regular set pressure.

3N0AQ06Z

The diagram shows pressure waveforms for equipment

without shockless pistons and equipment with shockless

pistons.

3N0AQ07Z

1 Without shockless piston

2 With shockless piston

3 Pressure

4 Time

5 Region of shockless piston operation

Make-up valve

The make-up valve (7) has two different functions.

One of the functions is preventing cavitation occurring

due to the piston motor being overrun, which prevents

the slew body from running uncontrolled.

3N0AQ08Z

When the motor is turned using the inertial force of the

slew both to create a pumping action and the motor

speed in RPMs exceeds the speed in RPMs suitable for

the amount of oil supplied to the motor. Extra oil is sup-

plied from external to the main circuit of the motor via the

make-up valve (7) to make up for any lack of oil and to

prevent a vacuum from forming within the circuit.

3N0AQ02Z

SLEW MOTOR

3N0AS00

FUNCTION

SLEW MOTOR 3

The other function is to prevent a vacuum from forming

inside the circuit through the supply of extra oil from the

make-up valve (7) to compensate for motor drain and

valve leaks to enable a braking function to be obtained

under normal circuit conditions when the circuit between

control valve and motor is closed off, as with the brake.

3N0AQ03Z

Parking brake

With the parking brake ON

The parking park has a hydraulic-release, multiple-disc

structure and a locking mechanism with a switching axis

that operates to turn the brake ON and OFF using exter-

nal signal pressure.

With the hydraulics for releasing the break shut off, the

disc (11) coupled with the spline in the outer periphery of

the cylinder block (1) pushes against the brake piston

(12) (which is stopped to prevent it from rotating) with the

spring force, causing the cylinder block (1) and case to

be immobilized together by a frictional force. This causes

3N0AQ09Z

the shaft to be locked in place.

When the brake-release pressure is supplied to the

brake cylinder chamber (13) through the port PB, the

brake piston uses the release pressure to overcome the

spring force, which cancels out the frictional force acting

on the disc and enables the shaft to rotate freely.

3N0AQ10Z

SLEW MOTOR

3N0AS00

FUNCTION

SLEW MOTOR 3

Timer valve

The timer valve is used to prevent the parking brake from

being pulled during slew parking. While the inertial slew

force is being absorbed by the dynamic hydraulic brake,

the timer valve has the role of working to secure a delay

time period during which the parking brake does not op-

erate, with the delay time being set by the opening in the

orifice from which the discharge oil discharges from the

brake cylinder chamber and by the flow rate.

While the parking brake is activated, the pilot pressure

continuously flows into the port PG, and the spool (14) is

shifted to the left position by the spring (15) force, which

causes the port PG to close.

3N0AQ11Z

When the slew pilot pressure or arm pulling (CROWD) pi-

lot pressure is introduced into the port SH, the pilot pres-

sure overcomes the spring (15) force and moves the

spool to the right, causing the port PG to open.

The pressure oil in the port PG flows into the port PB for

releasing the parking brake through the center hole on

the spool (14), which releases the parking brake func-

tion.

3N0AQ12Z

If the pilot pressure in the port SH decreases to zero, the

spool (14) is moved to the left by the spring (15) force,

the port PG closes, and the oil in the brake cylinder

chamber is also shut off. The oil that is shut off slowly

flows into the drain port dr from the orifice (16) in the pe-

riphery of the spool (14). This works as a timer that acti-

vates the parking brake after a certain amount of time so

as to prevent sudden operation of the parking brake.

3N0AQ13Z

SLEW MOTOR

3N0AS00

FUNCTION

SLEW MOTOR 3

Reduction gears

The motor shaft (1) connects the drive gear (2) and the

spline. The driving force of the hydraulic motor is trans-

mitted to the planetary gears (3) that are meshed with the

drive gear (2). The planetary gears (3) are meshed with

the ring gear in the reduction gear housing (4). This al-

lows the planetary gears to move in orbital motion along

the ring gear while rotating.

The planetary gears (3) are held in position via the bear-

ings in the holder (5), and the holder (5) transmits the or-

bital motion of the planetary gears (3) to the sun gear (6)

connected to the spline. The sun gear (6) meshes with

the planetary gears (7) and transmits the rotating motion

to the planetary gears (7) as in the first stage. The plane-

tary gears (7) mesh with the ring gear in the housing,

which allows them to move in orbital motion while rotat-

ing. The planetary gears (7) mesh with the ring gear in

the housing, which allows them to move in orbital motion

while rotating. The planetary gears (7) are held in posi-

tion via the bearings in the holder (8), and the holder (8)

transmits the orbital motion of the planetary gears (7) to

the pinion shaft connected to the spline.

SLEW MOTOR

3N0AS00

FUNCTION

SWIVEL JOINT

The swivel joint is located at the slew center of the ma-

chine and has the role of maintaining the connection to

the oil circuit regardless of the slew angle of the upper

frame.

A number of ports (3) equal to the number of fluid circuits

is provided on a hub (1) and shaft (2) that are mutually

rotatable. Grooves used as oil passages are processed

into the inner periphery of the hub (1) and the outer pe-

riphery of the shaft (2). A seal is applied to the top and

bottom of the peripheral grooves. The oil flowing from the

port (3) continues to flow through the oil pressure pas-

sage (5) between the hub (1) and shaft (2) to enable con-

tinued connection of the circuit located between the slew

assemblies without it being blocked due to rotation.

SWIVEL JOINT

3O0AS00

Takeuchi Hydraulic excavator TB1140 (Serial No. 514400002~). Operator's Manual - page 3