5.2.2 Brake valve (See Fig. 5.3)
5.2.2 Brake valve (See Fig. 5.3)
(1) Non-brake status
(1) Non-brake status
In case of not-braking state and due to opening of port A of brake valve , the pump
In case of not-braking state and due to opening of port A of brake valve , the pump
interface and the steering interface are interlinked and the steering works normally. When
interface and the steering interface are interlinked and the steering works normally. When
the brake pedal is not stepped on, even if
the brake pedal is not stepped on, even if
the steering operation will not produce braking,
the steering operation will not produce braking,
the oil pressure of cont
the oil pressure of cont
rol oil pressure ch
rol oil pressure ch
amber D will not rise as the port B is closed at this
amber D will not rise as the port B is closed at this
time.
time.
(2)Starting and finishing of the braking
(2)Starting and finishing of the braking
A 、When the brake
A 、When the brake
pedal is stepped on, the piston assembly (part
pedal is stepped on, the piston assembly (part
NO.10) moves to
NO.10) moves to
the left , the valve sleeve (part
the left , the valve sleeve (part
NO.7) and backflush piston (part NO.5) are pressed to the
NO.7) and backflush piston (part NO.5) are pressed to the
left side by the spring set (part NO.8) and meanwhile the return spring (part NO.6) is
left side by the spring set (part NO.8) and meanwhile the return spring (part NO.6) is
compress
compress
ed to the left side .
ed to the left side .
B、The movement of work piece (part NO.7)
B、The movement of work piece (part NO.7)
closes the place A,
closes the place A,
breaks the interface
breaks the interface
of D and oil return tank. B opens correspondingly and makes D chamber and pump
of D and oil return tank. B opens correspondingly and makes D chamber and pump
interface connect.
interface connect.
C、At this time, the valve sleeve (part NO.7) moves to the left and the oil pressure
C、At this time, the valve sleeve (part NO.7) moves to the left and the oil pressure
that leads to the sub-pump of brake rises along with
that leads to the sub-pump of brake rises along with
the increase of oil pressure of pump
the increase of oil pressure of pump
interface and chamber D due to compression. Meanwhile, the relatively higher oil pressure
interface and chamber D due to compression. Meanwhile, the relatively higher oil pressure
in chamber D moves to the right and push the backflush piston (part NO.5) and this
in chamber D moves to the right and push the backflush piston (part NO.5) and this
pushing force is in balance with pedal force.
pushing force is in balance with pedal force.
D、
D、
When the maxi
When the maxi
mum pedal forc
mum pedal forc
e is input in the right end of pisto
e is input in the right end of pisto
n and in order that
n and in order that
the oil
the oil
press
press
ure of
ure of
D chamber will not
D chamber will not
exceed the maximum adjust
exceed the maximum adjust
ing oil
ing oil
pres
pres
sure, the
sure, the
bolts and pedal brackets are used for position limitation.
bolts and pedal brackets are used for position limitation.
E 、When your foot leaves off the pedal , the counterforce of backflush piston and the
E 、When your foot leaves off the pedal , the counterforce of backflush piston and the
spri
spri
ng counterfo
ng counterfo
rce of
rce of
work pieces (part NO.6) and
work pieces (part NO.6) and
(part NO.8) return the valve sleeve
(part NO.8) return the valve sleeve
(part NO.7) to the original position and the braking process is finished.
(part NO.7) to the original position and the braking process is finished.
(3)The working process of accumulator
(3)The working process of accumulator
When the oil pump stops working, ( due to engine stops) or is damaged, the
When the oil pump stops working, ( due to engine stops) or is damaged, the
accumulator needs to enter into working state.
accumulator needs to enter into working state.
A 、When the brake pedal is further stepped on, valve sleeve (part NO.7), back flush
A 、When the brake pedal is further stepped on, valve sleeve (part NO.7), back flush
piston (part NO.5) and contact pin of check valve move together towards left,
piston (part NO.5) and contact pin of check valve move together towards left,
the contact
the contact
pin will prop open the ball and chamber D and accumulator are inte
pin will prop open the ball and chamber D and accumulator are inte
rlinked at this time and
rlinked at this time and
the pressure oil of accumulato
the pressure oil of accumulato
r is utilized to play the
r is utilized to play the
braking role for brake sub-pump.
braking role for brake sub-pump.
B. When your foot leaves off the peda
B. When your foot leaves off the peda
l, the valve sleeve , back flush pisto
l, the valve sleeve , back flush pisto
n and contact
n and contact
pin move to the right at the same time. The ball of the check valve restores joining with
pin move to the right at the same time. The ball of the check valve restores joining with
valve seat under the action of spring force (check valve closes) and the contact pin stops at
valve seat under the action of spring force (check valve closes) and the contact pin stops at
this position correspondingly.
this position correspondingly.
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