Takeuchi TB53FR, Workshop Manual

Page: 208 / 447

HYDRAULIC UNITS
TRAVEL MOTOR
IV-98
TB53FR
C4D554
B
C4D555
B
D
OPERATION
Hydraulic Motor
9 pistons (2) are fitted in the cylinder block (1) and
there is a valve plate (3) with two half moon ports, B
and C in the end. Also, the cylinder block (1) rotates
freely and is joined to the shaft (4) via the spline. On
the other band, the swash plate (5) is fastened to the
housing.
When high pressure oil is introduced into port B, one
piston (2) makes contact and force F bears on the
swash plate (5).
F = P
×
A P: Pressure A: Piston Sectional Area
The force F which the piston (2) applies to the swash
plate (5) is divided into force F1, which pushes the
plate, and force F2, which rotates the cylinder block
(1). The total sum of the components in the direction
of rotation of the high pressure side piston generates
a rotational force in the cylinder block (1) and via the
spline, torque is transmitted to the shaft (4), turning it.
Conversely, if high pressure oil is introduced to port
C, rotation is the reverse of the above.
Counterbalance Valve
If high pressure oil is introduced to port P1, the oil
pushes the check valve (6) up. This causes oil to flow
through the motor port M1 and to flow into chamber
B of the pilot portion and fill it. When hydraulic oil
flows the motor from port M1 and acts to turn the
motor, even if oil returns from the motor and flows
into port M2, since the flow is cut off by the check
valve (6), the pressure at port P1 and in chamber B
rises. If the pressure in chamber B becomes higher
than the set valve of the spring (7), the spool (8) moves
to the left side and ports M2 and P2 open up, causing
the motor to turn.
If the motor’s turning becomes too fast, and the
amount of oil flowing out of port M2 is greater than
the amount of oil flowing into port M1, the pressure
in port P1 and chamber B drops. When the pressure in
chamber B drops below the set valve of the spring (7),
the spool (8) attempts to return to the right side. As a
result, since the resuming oil is constricted at portion
D, back pressure is generated at port M2 and the
motor’s turning is slowed.