Hyundai HX145 LCR, Manual

Page: 118 / 702

2-66
High/low speed changeover mechanism High/low speed changeover mechanism
At low speed At low speed - pilot pressure of less than 10 kgf/cm 2
When no pilot pressure is supplied from (D) (at a pressure of 10 kgf/cm
2
or less), valve (65) is
pressed toward the top by the force of spring (66) and (A) port or (B) port, the pressurized oil
supply port (C) is shut off, and oil in chamber (P) is released into the motor case via
valve(65). Consequently, swash plate (3) is tilted at a maximum angle (
຀
1) and the pis-
ton displacement of hydraulic motor becomes maximum, thus leading to low-speed rotation.
A B
C
A
B
Pilot pressure
D
66
65
3
1
Y side
61
P
Drain
At high speed At high speed - pilot pressure of 20 kgf/cm 2 or more
When a pilot pressure is supplied from port (D) (at a pressure of 20 kgf/cm
2
or more), the pressure
overcomes the force of spring (66) and (A) port or (B) port of valve (65) is pressed toward the
down. The pressurized oil at supply port (C) is then introduced into chamber (P) via valve (65). Pis-
ton (61) pushes up swash plate (3) until it touches side Y of the spindle. At this time, swash plate (3)
is tilted at a minimum angle (
຀
2) and the piston displacement of hydraulic motor becomes mini-
mum, thus leading to high-speed rotation.
A B
C
A
B
Pilot pressure
D
66
65
3
2
X side
61
P
14092TM10
14092TM11
(4) (4)
①
②