Đây là tài liệu sửa chữa của các xe nâng kiểu FD60Z8, FD70Z8, FD80Z8, FD90Z8, FD100Z8 của hãng xe nâng TCM Nhật Bản.
4. BRAKE SYSTEM
The brake valve is operated under the valve open or c10sed state. Their operating principles are as
follows:
(1) Operation when the valve opens
① When the brake pedal is pressed，th e input piston⑪ moves to the left，a nd the spring ⑨ presses the
valve spool ③ and the reaction piston⑥ to the left against the return spring ⑦.
② When the valve spool is moved to the left，囚isc10sed and the control hydraulic chamber is shut off
from the reservoir port. After that，固opensso that the controlled oil pressure chamber leads to the
pump port.
③ When the valve spool ⑧ is further moved to the left from the position shown in step②，固IS
throttled to increase the oil pressure at the pump port，so that the oil pressure in the controlled oil
chamber and the wheel cylinder increases. The oil pressure in the controlled oil pressure chamber
presses the reaction piston to the right，pr oducing pedal pressing force.
A nut comes up against the brake valve body to prevent the oil pressure in the controlled oil pressure
chamber from exceeding the maximum adjustment oil pressure when the input piston is operated with
the maximum pressing force.
When the pedal is released，th e valve spool returns to the original position by the counter force of the
reaction piston and the return spring.
(2) Operation when the valve is closed
When the power steering wheel is operated without applying the power brake，t he oil pressure at the
pump port increases，bu t the oil pressure in the controlled oil pressure chamber does not increase due to固
being c1osed. Therefore，e ven if the steering wheel is operated without pressing the brake pedal，th e brake
won't be applied. When the brake pedal is depressed in this state，囚isc10sed and国opehsby the valve
spool movement，a nd the oil flows from the pump port into the braking oil pressure chamber to increase
the oil pressure in the wheel cylinder.
(3) Accumulator operation
When the pump is not operating (i.e. the engine is shut of f)， the brake valve operates in the same
manner as above，ex cept the following.
① The oil pressu回inthe wheel cylinder does not increase since the oil pressure is not produced at the
pump port under the condition described in step② of (1)
② When the pedal is further pressed in this state shown in step①， the valve spool，th e reaction piston
and the valve rod move to the left as au nit，a nd the valve rod presses and opens the ball. The
controlled oil pressure chamber opens to the accumulator port so that the oil pressure at the
accumulator port operates the wheel cylinder.
③ When the pedal is released，th e valve spool，re action piston and the valve rod move to the right at the
same time，an d the ball is seated to the valve seat by spring force.
④ When the ball come in c10se contact with the valve seat，th e valve rod stopsほthぽposition.When
the reaction piston moves further，閏and回openin this order. When the回opens，the oil in the
wheel cylinder returns to the reservoir through the controlled oil pressure chamber.
(8) Carefully remove the ball nut assembly from the
gear box. Keep the ball nut horizontal at all
times. Failure to do so will damage the ball
scoopmg紅白， resulting in the malfunction of the
ball nut assembly.
5.2.2 INSPECTION
5. STEERING SYSTEM
Fig.5.18
Clean all the disassembled metal parts in c1eaning oil and prepare new "O"-rings and oil seals. After
c1eaning，in spect all parts for scratches or scores，w ear or cracks. Put them in ap lace free from dust and
dirt until reinstallation.
(1) Replace the "O"-rings and oil seals with new ones. Check the side cover bushings for damage or
wear，re placing any defective ones.
(2) Operate the ball nut assembly to see if it is operating normally. If not，c1 ean it，sl owly operating in
c1eaning oil. Replace the ball nut assembly when the threaded grooves show sign of flaking，de nt，or
undue wear.
(3) Inspect the sector shaft for evidence of excessive scores on the gear teeth or undue wear on the shaft.
Replace the sector shaft if defective.
(4) Inspect the radial bearing and side cover bushing in the gear box assembly to see if they are
excessively WOfll. Replace if necess訂y.
(5) Inspect the radial bearing inside the top cover for defect. Replace if necessary.
(6) Inspecting the control valve
① Inspect the valve housing inner surface，es pecially the orifice areas for sign of battering or damage. If
unsatisfactory，re place the control valve assembly.
② Inspect the spool diameter and orifice areas for sign of battering and damage. If unsatisfactory，
replace the spool.
③ Inspect the spring for cracks or breakage，re placing the spring if defective.
④ Check whether the reaction piston is sliding smoothly inside the valve housing. If unsatisfactory，
replace the valve assembly.
Tile: Service manual của xe nâng kiểu FD60-100Z8 của hãng TCM Nhật Bản
Language: Multilingual
Size: 28.1 MB
Format: PDF
4. BRAKE SYSTEM
The brake valve is operated under the valve open or c10sed state. Their operating principles are as
follows:
(1) Operation when the valve opens
① When the brake pedal is pressed，th e input piston⑪ moves to the left，a nd the spring ⑨ presses the
valve spool ③ and the reaction piston⑥ to the left against the return spring ⑦.
② When the valve spool is moved to the left，囚isc10sed and the control hydraulic chamber is shut off
from the reservoir port. After that，固opensso that the controlled oil pressure chamber leads to the
pump port.
③ When the valve spool ⑧ is further moved to the left from the position shown in step②，固IS
throttled to increase the oil pressure at the pump port，so that the oil pressure in the controlled oil
chamber and the wheel cylinder increases. The oil pressure in the controlled oil pressure chamber
presses the reaction piston to the right，pr oducing pedal pressing force.
A nut comes up against the brake valve body to prevent the oil pressure in the controlled oil pressure
chamber from exceeding the maximum adjustment oil pressure when the input piston is operated with
the maximum pressing force.
When the pedal is released，th e valve spool returns to the original position by the counter force of the
reaction piston and the return spring.
(2) Operation when the valve is closed
When the power steering wheel is operated without applying the power brake，t he oil pressure at the
pump port increases，bu t the oil pressure in the controlled oil pressure chamber does not increase due to固
being c1osed. Therefore，e ven if the steering wheel is operated without pressing the brake pedal，th e brake
won't be applied. When the brake pedal is depressed in this state，囚isc10sed and国opehsby the valve
spool movement，a nd the oil flows from the pump port into the braking oil pressure chamber to increase
the oil pressure in the wheel cylinder.
(3) Accumulator operation
When the pump is not operating (i.e. the engine is shut of f)， the brake valve operates in the same
manner as above，ex cept the following.
① The oil pressu回inthe wheel cylinder does not increase since the oil pressure is not produced at the
pump port under the condition described in step② of (1)
② When the pedal is further pressed in this state shown in step①， the valve spool，th e reaction piston
and the valve rod move to the left as au nit，a nd the valve rod presses and opens the ball. The
controlled oil pressure chamber opens to the accumulator port so that the oil pressure at the
accumulator port operates the wheel cylinder.
③ When the pedal is released，th e valve spool，re action piston and the valve rod move to the right at the
same time，an d the ball is seated to the valve seat by spring force.
④ When the ball come in c10se contact with the valve seat，th e valve rod stopsほthぽposition.When
the reaction piston moves further，閏and回openin this order. When the回opens，the oil in the
wheel cylinder returns to the reservoir through the controlled oil pressure chamber.
(8) Carefully remove the ball nut assembly from the
gear box. Keep the ball nut horizontal at all
times. Failure to do so will damage the ball
scoopmg紅白， resulting in the malfunction of the
ball nut assembly.
5.2.2 INSPECTION
5. STEERING SYSTEM
Fig.5.18
Clean all the disassembled metal parts in c1eaning oil and prepare new "O"-rings and oil seals. After
c1eaning，in spect all parts for scratches or scores，w ear or cracks. Put them in ap lace free from dust and
dirt until reinstallation.
(1) Replace the "O"-rings and oil seals with new ones. Check the side cover bushings for damage or
wear，re placing any defective ones.
(2) Operate the ball nut assembly to see if it is operating normally. If not，c1 ean it，sl owly operating in
c1eaning oil. Replace the ball nut assembly when the threaded grooves show sign of flaking，de nt，or
undue wear.
(3) Inspect the sector shaft for evidence of excessive scores on the gear teeth or undue wear on the shaft.
Replace the sector shaft if defective.
(4) Inspect the radial bearing and side cover bushing in the gear box assembly to see if they are
excessively WOfll. Replace if necess訂y.
(5) Inspect the radial bearing inside the top cover for defect. Replace if necessary.
(6) Inspecting the control valve
① Inspect the valve housing inner surface，es pecially the orifice areas for sign of battering or damage. If
unsatisfactory，re place the control valve assembly.
② Inspect the spool diameter and orifice areas for sign of battering and damage. If unsatisfactory，
replace the spool.
③ Inspect the spring for cracks or breakage，re placing the spring if defective.
④ Check whether the reaction piston is sliding smoothly inside the valve housing. If unsatisfactory，
replace the valve assembly.
Tile: Service manual của xe nâng kiểu FD60-100Z8 của hãng TCM Nhật Bản
Language: Multilingual
Size: 28.1 MB
Format: PDF
