4transmission system englisg-g9180
DESCRIPTION
Transmission System ENGLISG-G9180TRANSCRIPT
Service Manual of RS8160 Road Roller
4 Transmission System
SERVICE MANUAL
Service Manual for G9180 Grader
I
CONTENTS
4 Transmission System ........................................................................................... 4-1
41 Hydraulic Torque Converter-Transmission Box System .................................... 4-1
411 General ......................................................................................................... 4-1
412 Mechanical Principles for Gear Shifting ..................................................... 4-5
413 Transmission Control System...................................................................... 4-5
414 Pressure Test of Transmission Box ............................................................. 4-8
415 Operation and Maintenance of YD13 Power Shifting Transmission Box .. 4-9
416 Disassembly and Assembly of Transmission System ............................... 4-12
417 Precautions ................................................................................................. 4-25
42 Transmission Shaft System ............................................................................... 4-26
421 Overview of Transmission Shaft ............................................................... 4-26
422 Disassembly and Assembly of Transmission Shaft Assembly ................. 4-28
43 Drive Axle System ............................................................................................. 4-30
431 Overview of Drive Axle ............................................................................ 4-30
432 Main Reducer and Differential Assembly ................................................. 4-31
433 Wheel Reducer Assembly ......................................................................... 4-32
434 Balancing Box Assembly .......................................................................... 4-32
435 Disassembly and Assembly of Drive Axle and Balancing Box ................ 4-32
436 Use, Maintenance and Repair of Drive Axle ............................................ 4-36
44 Diagnosis and Solutions for Common Fault of Transmission System ............. 4-38
441 Common Faults of Transmission Box ....................................................... 4-38
442 Common Faults of Drive Axle .................................................................. 4-39
Service Manual for G9180 Grader
4-1
4 Transmission System
Transmission system of G9180 grader is composed of transmission box, transmission shaft, and
drive axle. The principle diagram of transmission system is shown in Fig. 4-1.
Fig. 4-1 G9180 grader power transmission diagram
1 Engine 2 Hydraulic torque converter + transmission box 3 Balancing box
4 Differential 5 Transmission shaft 6.Left working pump 7 Right working pump
41 Hydraulic Torque Converter-Transmission Box System
411 General
G9180 grader is equipped with ZFW320 torque converter and YD13 transmission box. Because of
the design, 6 forward gears and 3 reverse gears can be realized to satisfy different working
conditions.
Basic parameters of hydraulic torque converter-transmission box assembly are listed in Table 4-1.
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Table 4-1
Hydraulic torque
converter
Model ZFW320
Torque ratio 1.940
MBgo 133.3NM
Inlet pressure of converter (MPa) 0.8~1.0MPa
Outlet pressure of converter (MPa) 0.25~0.4MPa
Transmission box
Shifting gears Forward-6-Reverse-3
Structural style Fixed shaft
Shifting pressure (MPa) 1.3~1.8MPa
Transmission
ratio
Forward I 5.986
Forward II 3.42
Forward III 2.594
Forward IV 1.48
Forward V 1.178
Forward VI 0.672
Reverse I 5.986
Reverse II 2.594
Reverse III 1.178
The torque converter is of single-stage single-phase three-component structure without lockup
clutch (see Fig. 4-2). It is composed of pump impeller, turbine and guide wheel, and a circulating
system is formed by the three components, i.e., the oil circulates in the way of “pump impeller —
turbine — guide wheel”. The mechanical energy outputted by engine is converted into hydraulic
energy by the pump impeller, and then converted into mechanical energy again by the turbine. The
transmission oil pump continuously supplies pressure oil to torque converter, in this way can the
torque converter work to increase engine output torque. Meanwhile, the circulating transmission oil
also absorbs the heat produced by the torque converter, and dissipates it through the radiator for
cooling.
The transmission oil flows into the turbine from the pump impeller, and changes its direction
through the turbine. The outputted torque by turbine depends on the loads. The guide wheel
(reverse-acting component) is installed between the turbine and pump impeller, it can change the
direction of return oil from turbine and send it back to pump impeller, thus, there is reverse-acting
force acted on the guide wheel. The torque ratio of turbine and pump impeller is termed as torque
ratio of the converter. Generally the torque ratio increases as speed ratio of turbine and pump
impeller deceases. When turbine speed reaches 80% of the pump impeller speed, the torque ratio is
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close to 1, which means the turbine torque is equal to pump impeller torque, the torque converter is
a coupler in this case. When speed of turbine is close to zero (zero-speed working condition), the
torque ratio reaches the maximum value, as the output speed increases, the torque ratio will reduce.
Since a torque converter is designed in the system, stepless speed change can be achieved, and
variety of load can be adapted to automatically. In this way, the grader is able to work under all
kinds of conditions, the labor intensity is reduced and service life of grader can be prolonged.
Fig. 4-2 Hydraulic torque converter
The transmission box is of fixed shaft electric hydraulic control (EHC) power shift type, gear
shifting operation can be carried out without cutting off the power by engaging the clutches (with
wet-type friction plates). The transmission box is designed with 6 multi-friction-plate clutches.
When shifting, the pressure oil will push axially to engage the corresponding clutches. Detaching of
clutch is realized by action of return spring force.
YD13 is multi-gear power shift transmission box, it adopts parallel shaft (fixed shaft) transmission,
and all transmission gears are supported by antifriction bearings. Constant mesh transmission is
applied between the transmission gears. Cooled oil is used to lubricate the clutches and bearings.
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4-4
1 Oil filter
2 Transmission control valve
3 Measuring port of torque converter
oil temperature
4 Oil outlet From torque converter to
radiator
5 Oil absorption pipe
6 Transmission box housing
7 Nameplate
8 Lifting bolt
9 Auxiliary power takeoff
10 Main power takeoff
11 KVK1 clutch shaft
12 KRK2 clutch shaft
13 K3K4 clutch shaft
14 Parking brake
Fig. 4-3 YD13 transmission box assembly
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412 Mechanical Principles for Gear Shifting
The transmission box is designed with 6 multi-friction-plate clutches, i.e., K1, K2, K3, K4, KV and
KR, and KR is the reverse gear clutch. Each gear requires two engaging clutches, the working
principle diagram of transmission box is illustrated below.
Fig. 4-4 Working principle diagram of transmission box
413 Transmission Control System
YD13 transmission box adopts electro-hydraulic control, a gear selector is installed on the right side
of operator’s seat (see Fig. 4-5). The transmission solenoid valves that connected with the gear
selector are used to control the hydraulic slide valves to carry out gear shifting operation. Gear
shifting operation should be performed orderly, do not skip any gears. The transmission control
pump, which is used to supply oil to torque converter and transmission control valve, is placed
inside transmission box. The pump is directly driven by engine, and its output flow
Q=35L/1000r/min. The pump absorbs oil from oil pan through the oil absorption filter (pre-filter)
and sends it to the fine filter on top of transmission box housing. The filter fineness is 0.025um, and
filter area is 5100cm2. Besides, the filter is designed with a bypass valve for safety protection.
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The control pressure valve (main pressure regulating valve) is used to limit the pressure of oil from
the filter, after being regulated, the oil will flow into transmission control valve through the pressure
control valve. The function of pressure control valve is to adjust pressure rise characteristics of the
clutch oil cylinder in the moment of gear shifting operation. In the moment of gear shifting, the oil
pressure will reduce, the pressure control valve can rebuild the pressure to 1.3~1.8MPa (set value of
control pressure valve) after the shifting process. In this way, impact of shifting is reduced and
shifting quality of transmission box is improved. The pressure oil from transmission control valve
goes directly to the corresponding clutches.
In addition to limit the pressure of transmission control oil, the control pressure valve also sends the
overflowed oil to torque converter and lubricating oil line in the meantime. A safety valve with
opening pressure of 0.8MPa is installed in the oil inlet of torque converter, to avoid oversized oil
pressure from damaging the components inside the torque converter. As we know, according to the
hydraulic transmission principle of torque converter, oil is the medium of energy delivering inside
the converter. Thereby, to prevent cavitation, the torque converter should always be fully filled with
oil, and this is guaranteed by the pressure control valve (counterbalance valve, with opening
pressure of 0.25MPa) installed in the oil outlet of torque converter.
The overflowed oil from torque converter flows directly into oil cooler of the vehicle. If the vehicle
adopts water-cooled engine, the cooler should be installed on the engine cooling water exit end. The
cooler must be designed with bypass valve for protection in case of low temperature or blockage.
The oil from oil cooler flows directly into transmission box lubricating oil line, to provide sufficient
lubricating oil for all lubricating points.
Fig. 4-5 Gear selector
Neutral gear Reverse gears
Forward gears
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The corresponding working condition of transmission solenoid valves and clutches in each gear are
shown in Table 4-2.
Table 4-2
●Solenoid valve is electrically charged Engaged clutches
M1 M2 M3 M4
Forward I ● ● ● KV K1
Forward II ● ● ● K4 K1
Forward III ● ● KV K2
Forward IV ● ● K4 K2
Forward V ● KV K3
Forward VI ● K4 K3
Reverse I ● ● ● ● KR K1
Reverse II ● ● ● KR K2
Reverse III ● ● KR K3
Neutral gear — K3
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Fig. 4-6 Electro-hydraulic control principle of YD13 hydrodynamic transmission box
414 Pressure Test of Transmission Box
ATTENTION
Keep the engine running and make sure the transmission box oil temperature is within
80~95oC when measuring the transmission oil pressure. Standard transmission oil
pressure is 1.3~1.8MPa.
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Fig. 4-7 Fig. 4-8
Pressure measuring points:
3= Inlet oil pressure of torque converter 2= Outlet oil pressure of torque converter
5= K2 clutch oil pressure 6= K1 clutch oil pressure 7= K3 clutch oil pressure
8= Control oil pressure 9= K4 clutch oil pressure 10= KR clutch oil pressure
11= KV clutch oil pressure
Temperature measuring point:
4= Torque converter oil outlet
Flow measuring points:
1= Filter inlet 2 Filter outlet (Min. flow is 50L/min)
Specification of connecting thread of each measuring point:
Table 4-3
Measuring point Specification
3, 5, 6, 7, 8, 9, 10, 11 M10×1
1, 2 M26×1.5
415 Operation and Maintenance of YD13 Power Shifting Transmission
Box
Oil filling
SAE 15W-40 diesel engine oil is applicable to the transmission box, fill approx. 28L for the first
time. The oil filling port and oil dipstick of transmission box is on left-front side of rear frame.
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Fig. 4-9 Fig. 4-10 Transmission box oil dipstick
Check the oil level:
——Park the grader on a flat place.
——Put the gear shifting handle of transmission box in the neutral position "N".
——Make sure the transmission box oil temperature is within normal operating temperature e.
——Run the engine at idle status (about 750r/min).
——Loosen the oil dipstick clockwise and remove the oil dipstick. Clean it.
——Insert the oil dipstick and tighten it. Then take it out to read the oil level (do this at least twice).
——When the oil temperature is 104°F (40°C), oil level should be between bottom scale and
middle scale (ZONE COLD).
——When the oil temperature is 176°F (80°C), oil level should be between highest scale and
middle scale (ZONE HOT).
1. Since the oil in the torque converter, cooler and oil pipes will flow back to the transmission oil
pan when the engine stopped, so when checking oil level, the grader should be stopped in
neutral position and let the engine run at idle status to keep the oil in transmission box stay in
normal working temperature. If the engine is not running when checking the oil level, the oil
level should above the “HOT” scale on oil dipstick (see Fig. 4-10). After the first 100 working
hours of the grader, the oil must be replaced. Since then, replace the oil at least every 500
working hours or every year, and the filter should be replaced at the same time.
2. When checking the oil level of the transmission box, related safety regulations and instructions
must be strictly complied with. For instance, Wedge the tires with wood blocks to prevent
movement, lock the hinged frames with frame locking bar, etc.
3. The gear shifting handle must be in the neutral position before checking oil level.
Transmission box oil dipstick
Transmission box oil filling port
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4. When the oil temperature is 80oC, the oil level should between the middle and the top scale line
of the oil dipstick.
When the oil temperature is 40oC, the oil level should between the middle and the low scale
line of the oil dipstick.
When draining oil, only a part of oil can be discharged from the oil drain holes.
5. When cleaning the oil filter in main oil line, avoid intrusion of oil dirt and impurities. Besides,
installed a cover plate to the brake to prevent oil from dropping into the brake.
6. When installing the filter, avoid exerting external force on the filter and do not tighten it too
tight.
Method to tighten the filter: Coat a thin layer of oil on the seal ring first, screw it into the
mounting hole until contacting with the fitting surface, and then tighten it for another 1/3~1/2
circle by hand or special tool. Pay attention to check the whether bypass valve inside the filter
is in open state.
Driving and shifting gears
When starting the engine, you must confirm that the gear shifting handle is in neutral position. For
safety's sake, before the engine started, the grader must be in the braking state, so the grader won’t
move after the engine started.
After the engine started, remove parking brake state and adjust traveling direction, then shift proper
gear, stamp the accelerator pedal to move to grader. During driving, torque converter supersedes
main clutch. You can shift high gears when the road is clear.
If the grader has stopped moving and the engine is still running, engage a gear at this point, the
engine may not flameout, and on a flat road, the grader may crawl, that’s because tractive force can
be produced by the torque converter when the engine is running at idle status. The right
countermeasure is: put the parking brake in braking state every time you stop the grader. If the
grader needs to stop for a long time, the gear shifting handle must be in neutral position.
When the grader is travelling, the parking brake must be relieved, but what we learned from
experience is that it’s difficult for the operator to immediately find out the parking brake state is not
released, that’s because the large output torque ratio produced by torque converter, which can
overcome braking torque and force the grader to move even under normal operating conditions.
Then the consequence is the torque converter oil temperature rising sharply and overheated brake.
Slow down the machine before turning. Max. running speed during steering should not exceed
10km/h.
Lubricating oil flow rate of transmission box is subject to engine speed, so keep engine speed high
than 1200r/min during driving.
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Pausing and parking
Since there is no rigid connection between engine and torque converter output shaft, so when
parking on a slope (up/down) and the driver intends to leave, in order to prevent slide phenomenon
occurred, we suggest that the grader should not only be braked, but also be wedged with blocks
under the tires.
Towing
The maximum towing speed is 10 km/h, and the maximum towing distance is 10 km. When the
destination is far away, a truck is needed to transport the malfunctioned grader.
416 Disassembly and Assembly of
Transmission System
ATTENTION
Wait until the transmission box is cooled to
do the disassembly.
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In the process of disassembly, the joints of
each pipeline should be bound up to avoid
the sundries entering.
Disassembly of transmission box
1. Wedge the tires with wood blocks properly.
2. Remove the engine hood , cab and platforms.
Refer to 8 Cab & Covering Parts System.
3. Remove the transmission control oil pressure
sensor.
ATTENTION
After removing the pressure sensor, take
measures to protect the exposed oil port and
the pressure sensor should be properly kept.
1
Fig. 4-11
1 Wood block
1 2
Fig. 4-12
1 Engine hood 2 Cab
1
Fig. 4-13
1 Transmission control oil pressure
sensor
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4. Remove the hydraulic oil tank, refer to 9
Working Hydraulic System.
5. Drain transmission box oil.
ATTENTION
In routine maintenance, drain oil from the
specialized oil drain port. When
disassembling the transmission box, you can
drain oil form the oil drain port or remove
the oil filling pipe to drain oil, tighten the
plug timely after draining to prevent
intrusion of foreign matters.
6. Disconnect the transmission box vent pipe.
1
Fig. 4-14
1 Hydraulic oil tank assembly
1
Fig. 4-15
1 Oil drain plug
1
Fig. 4-16
1 Vent pipe
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7. Disconnect the control wire of transmission
control valve.
8. Remove the transmission oil temperature
sensor.
ATTENTION
After removing the temperature sensor, take
measures to protect the exposed oil port and
the pressure sensor should be properly kept.
9. Disconnect the transmission box to radiator oil
pipe.
1 2
Fig. 4-17
1 Transmission control valve
2 Control wire
1
Fig. 4-18
1 Oil temperature sensor
1
Fig. 4-19
1 Transmission box to radiator oil pipe
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10. Disconnect the radiator to transmission box oil
pipe.
11. Remove the connecting bolts of transmission
shaft and transmission box.
12. Remove the oil inlet and outlet pipes of
working pump and steering pump.
ATTENTION
Disconnect the oil pipe slowly to prevent oil
splashing. Take measures to protect the
exposed oil ports to prevent intrusion of
1
Fig. 4-20
1 Radiator to transmission box oil pipe
1 2
Fig. 4-21
1 Bolt
2 Transmission shaft assembly
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foreign matters.
13. Remove the parking brake control wire.
14. Remove the cover plate of transmission box.
15. Remove the connecting bolts of torque
converter housing and the connecting plate.
1
Fig. 4-23
1 Parking brake control wire
1 2
Fig. 4-24
1 Cover plate 2 Bolt
1 2
Fig. 4-25
1 Connecting plate 2 Bolt
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16. Remove the connecting bolts of torque
converter housing and engine flywheel
housing.
ATTENTION
Before removing the connecting bolts, you
must support the engine prevent it falling.
17. Remove the fixing bolts of transmission box
support.
18. Lift down the transmission box.
Connect lifting rope to the two lifting eyes on
transmission box, lift it up slowly and pay
attention not to extrude or drag the cables and
pipes.
1
Fig. 4-26
1 Bolt
1
Fig. 4-27
1 Bolt
1 2
Fig. 4-28
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ATTENTION
Lift the transmission box smoothly and do
not tilt to prevent the torque converter
slipping.
Assembly of transmission box
1. Connect the lifting appliance to the
transmission box.
2. Lift the transmission box to the right position.
ATTENTION
Fig. 4-29
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Lift the transmission box smoothly to
prevent the torque converter slipping.
Please be careful during operation and pay
special attention to the cables and hydraulic
hoses on the machine, otherwise, they may
be damaged by clamping or extruding.
3. Install the two upper bolts between the engine
and the transmission box.
4. Install and tighten the connecting bolts
between the engine and the transmission box.
5. Fix the transmission box support on frame
with bolts. Remove the lifting appliance
6. Install the connecting bolts of torque converter
housing and the connecting plate.
1 2 3
Fig. 4-31
1 Transmission box housing
2 Bolt
3 Engine flywheel housing
1
Fig. 4-32
1 Bolt
1 2 3
Fig. 4-33
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7. Install the cover plate of transmission box.
8. Install the radiator to transmission box oil
pipe.
ATTENTION
Before connecting the oil pipe, be sure to
clean the to-be connected oil ports.
9. Install the transmission box to radiator oil
pipe.
1
Fig. 4-36
1 Transmission box to radiator oil pipe
1
Fig. 4-35
1 Radiator to transmission box oil pipe
1 2
Fig. 4-34
1 Bolt 2 Cover plate
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10. Connect the oil inlet and outlet pipes of
working pump and steering pump.
ATTENTION
Before connecting the oil pipes, be sure to
clean the to-be connected oil ports.
11. Connect the transmission shaft to transmission
box.
110~130Nm
Apply 272 thread locking sealant to
the bolts
12. Install the parking brake control wire.
1 2
Fig. 4-37
1 Working pump 2 Oil pipe
1
1 2
Fig. 4-38
1 Bolt
2 Transmission shaft assembly
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13. Install the transmission oil temperature sensor.
ATTENTION
When installing the sensor, wrap the thread
end with thread seal tape to prevent
leakage.
14. Connect the control wire of transmission
control valve.
15. Connect the transmission box vent pipe.
1
Fig. 4-42
1 2
Fig. 4-41
1 Transmission control valve
2 Control wire
1
Fig. 4-40
1 Oil temperature sensor
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16. Install the hydraulic oil tank.
17. Install the transmission control oil pressure
sensor.
18. Install the engine hood, cab and platforms.
1 2
Fig. 4-45
1
Fig. 4-44
1 Transmission control oil pressure
sensor
1
Fig. 4-43
1 Hydraulic oil tank assembly
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19. Fill in transmission oil.
15W-40 diesel engine oil, about 28L
Run the engine idly and check the oil level
by using the oil dipstick.
417 Precautions
1. Maintenance and overhaul of transmission box should be carried out or guided by professional
staff.
2. Since the torque converter has no axial location, prevent it falling off when lifting.
1
Fig. 4-46
1 Oil filling port
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3. When the grader is travelling, the parking brake must be relieved, but what we learned from
experience is that it’s difficult for the operator to immediately find out the parking brake state is
not released, that’s because the large output torque ratio produced by torque converter, which
can overcome braking torque and force the grader to move even under normal operating
conditions. Then the consequence is the torque converter oil temperature rising sharply and
overheated brake. Parking brake can be used as emergency brake.
4. When the grader has problems and needs welding maintenance, you must disconnect the gear
selector control wires. Otherwise, the impact current during electric welding may burn the
internal wiring.
5. In the case of engine failure and the machine is not able to move, note that the maximum
towing speed is 10 km/h, and the maximum towing distance is 10 km.
6. When draining oil, all oil in transmission box, torque converter and radiator must be discharged
completely to avoid secondary pollution. Use unclean or unqualified oil will cause serious
problem.
42 Transmission Shaft System
421 Overview of Transmission Shaft
1. Structure and function of universal transmission device
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Universal transmission device of the grader is installed between the transmission box and the drive
axle. It usually consists of a universal joint assembly and transmission shaft, etc. (Universal
transmission device is customarily called the transmission shaft assembly). Since the axes of the
grader transmission box output shaft and drive axle input shaft are difficult to be aligned in line;
moreover, during the grader operation process, due to the unfairness road and work place, the
relative position of the two axes changes frequently. So we can’t apply rigid connection between the
output shaft of the transmission box and the input shaft of the drive axle, while we must adopt the
universal transmission device, which is made of two cross universal joints and a drive shaft. The
function of the universal transmission device is to solve the uncoaxiality between the transmission
box and the drive axle, to meet the needs of angle changing between the transmission box and the
drive axle, and pass the power of transmission box to the drive axle.
Rated working torque of the transmission shaft assembly equipped on G9180 grader is 4100Nm, the
axle deviation of the two universal joints is small than 3°, Zl-2 lithium lubricating grease is used for
lubrication, and swing angle of the universal joint is greater than 20°, so the grader is able to work
under all kinds of conditions.
Fig. 4-47 G9180 grader rear transmission shaft assembly
1 Universal joint 2 Hexagon bolt 3 Transmission shaft
2. Universal joint
(1) Structure of universal joint
The universal joint is the most complex part of the universal transmission device. According to its
speed characteristics, it can be divided into ordinary type (unequal angular velocity) universal joint
and equal angular velocity universal joint; according to its rigidity size, it can be divided into rigid
universal joint and flexible universal joint. The universal joint used on the grader universal
transmission device is ordinary cross rigid universal joint.
The ordinary cross rigid universal joint is composed of cross axle, needle bearing, oil seal and oil
cup, etc. In order to reduce the friction loss and improve the transmission efficiency, the joint is
equipped with a needle bearing between the cross axle journal and the sleeve, and the sleeve is fixed
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on the universal joint fork, to prevent the bearing falling off from the universal joint fork under the
action of centrifugal force. In order to lubricate the bearing, the interconnected oil passage is drilled
in the cross axle, and the groove is processed in the end face of the cross axle, so that, the
lubricating grease injected from the oil cup can reach to the working face of the needle bearing.
(2) Transmission characteristics of the cross universal joint
The cross universal joint has the characteristics of the non-constant velocity transmission. The
so-called "non-constant velocity transmission" is that if the driving shaft is rotating in a constant
angular velocity, the revolving speed of driven shaft is sometimes fast and sometimes slow. It
should be noted that so-called "non-constant velocity transmission" is that the angular velocity of
the driven shaft is non-uniform in one circle. But if driving shaft turns a circle, the driven also turns
a circle, the average speed is equal.
The non-constant velocity of the common cross universal joint can cause the driven shaft and its
connected transmission components to generate torsional vibration, thereby generating additional
alternating load, affecting the life of the components. For this reason, a method of "constant
velocity universal transmission" is produced: from the non-constant transmission of a single cross
shaft universal joint, we came up with an idea that if we adopt double cross universal joints
transmission between the two shafts (the output shaft of gearbox and the input shaft of drive axle),
then the non-constant velocity effect of the first cross universal joint is likely to be offset by the
second one, which can achieve constant velocity transmission between the two shafts.
3. Structure and characteristic of transmission shaft
The transmission shaft is an important part of the universal transmission device, usually used for the
connection between the transmission box and drive axle. Generally speaking, the transmission shaft
is composed of pipe sleeve fork assembly, universal joint fork and spline shaft assembly, etc.
During the operation of the grader, the relative position of the transmission box and drive axle
changes constantly, in order to avoid the movement interference, the transmission shaft has sliding
splined connection parts, which consisting of sliding fork and spline shaft, so that, to realize the
change of the length of the transmission shaft. In order to reduce abrasion, the transmission shaft is
equipped with filling grease oil cup, oil seal and spline sheath, etc. Make sure the lubrication of the
spline shaft in the sleeve fork, and prevent water and dust entering into the sliding spline.
422 Disassembly and Assembly of
Transmission Shaft Assembly
ATTENTION
Transmission shaft should be replaced as a
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whole once unqualified. It is forbidden to
use deformed, scrapped or cracked
transmission shaft assembly.
Pull up the hand brake to engage parking
brake.
Disassembly of transmission shaft assembly
1. Wedge the tires with wood blocks properly.
2. Remove the connecting bolts of transmission
shaft and transmission box.
3. Remove the connecting bolts of transmission
shaft and drive axle.
ATTENTION
When removing the bolts, you should hold
up the transmission shaft to prevent falling.
Assembly of transmission shaft assembly
1. Connect the transmission shaft to drive axle
with bolts.
110~130Nm
Apply 272 thread locking sealant to
1
Fig. 4-48
1 Wood block
1
Fig. 4-49
1 Bolt
1
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the bolts
2. Connect the transmission shaft to transmission
box with bolts.
110~130Nm
Apply 272 thread locking sealant to
the bolts
ATTENTION
Before assembling the transmission shaft,
you should check whether the universal
joints are normal, whether the transmission
shaft can stretch out and draw back axially.
Replace the transmission shaft immediately
if it is faulty.
43 Drive Axle System
431 Overview of Drive Axle
Drive axle is the key component of the grader transmission system, it is mainly used to enlarge the
torque from engine and allocate it to the left and right drive wheels, it also works as a differential to
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realize differential speed between left side and right side wheels. Moreover, drive axle housing also
plays a role of load-bearing and stress-passing.
G9180 applies three-part rear drive axle, which is specially designed for grader. Main drive axle is
installed with no-spin differential, swing balancing box with swing angle of ±15°, heavy roller
chain transmission, wheel side drum-type brake. Main reduction ratio is 3.7, wheel reduction ratio
is 3.26, balancing box reduction ratio is 1.474, and the total reduction ratio is 17.779. GL-5 85W-90
gear oil is applied as lubricating oil for the drive axle. The joint of balancing box assembly and
wheel reducer, and the balancing box assembly use grease as lubricant.
See Fig. 4-51 for transmission diagram of the drive axle and balancing box.
Fig. 4-51
1 Balancing box assembly 2 Main drive assembly 3 Differential assembly 4 Wheel reducer
The power transmission line:
Transmission shaft
Main reducer
Differential
Left p
inio
n
shaft
Rig
ht p
inio
n
shaft
Left p
lanet
carrierR
igh
t plan
et carrier
Left ch
ain
wh
eel shaft
Rig
ht ch
ain
wheel sh
aft
Left ch
ainR
ight ch
ain
Left d
rive
wheel
Rig
ht d
rive
wheel
432 Main Reducer and Differential Assembly
Main reducer assembly is composed of main drive, differential and input flange. The differential is
of no self-rotation type, also called as no-spin differential. When the vehicle is turning, the outside
wheel spins faster than the inside one, at this point, the outside driven ring separates from the drive
Service Manual for G9180 Grader
4-32
ring and relative rotation is formed between them. Because of tooth engagement, the middle ring
rotates together with the drive ring, so there is relative rotation between the outside driven ring and
the middle ring too. Hence, the outside driven ring moves upward along the tooth surface until
separated from the middle ring and drive ring, the differential function is in effect When the drive
wheel on one side is on ice or wet road, or off ground, the wheel on the other side can still transmit
100% of original torque to guarantee the machine excellent cross-country ability. The differential
function is done automatically, and no extra operation is need. Compared to common bevel gear
differential, the differential equipped on G9180 grader has better performance.
433 Wheel Reducer Assembly
The wheel reducer assembly adopts cylindrical-gear planetary transmission, power from differential
is transmitted to the sun gear through the axle shaft. The planet carrier is fixed, then power is
transmitted to the chain wheels in balancing box through the gear ring.
434 Balancing Box Assembly
G9180 applies drum-type-brake balancing box, one on each side of rear frame. The balancing box
adopts heavy roller chain transmission, it is supported on rear axle by a copper bush in the middle
of the box, and the lateral positioning is realized by double-row spherical roller bearings. The
balancing box has swing angle of ±15°, hence, not only the cross-country ability of the vehicle is
good, but also the working accuracy is improved. The chain wheel shaft adopts simply supported
beam structure, with strong rigidity and can satisfy all kinds of working conditions of the grader.
In the balancing box, the power is transmitted to the chain wheels through roller chain to realize
forward and backward move of the grader. Tensioning of the roller chain is realized by rotating the
eccentric bearing seat, refer to Section 436 for details.
435 Disassembly and Assembly of
Drive Axle and Balancing Box
ATTENTION
Park the machine on flat ground before
Service Manual for G9180 Grader
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disassembling, it’s forbidden to perform
maintenance work on a slope or uneven
ground.
Do not carry out the maintenance work
immediately when the machine is just
stopped, be sure to wait until the drive axle
is cooled.
In the process of disassembling and
assembling, all disconnected oil ports and
pipe joint should be wrapped up properly to
avoid intrusion of foreign matters.
Disassembly of drive axle
1. Wedge the tires with wood blocks properly.
2. Disconnect the brake oil pipes on both sides of
the balancing box.
3. Disconnect the breather pipe.
1
Fig. 4-52
1 Wood block
1
Fig. 4-53
1 Brake oil pipe
1
Service Manual for G9180 Grader
4-34
4. Remove the connecting bolts of transmission
shaft and drive axle.
5. Use high-torque pneumatic impact wrench to
remove the 8 fixing bolts of drive axle.
6. Connect lifting appliance to the tail of rear
frame, lift the frame up a bit.
7. Remove the wood blocks that used to fix the
rear tires, and push the rear drive axle
1
Fig. 4-55
1 Bolt
1
Fig. 4-56
1 Fixing bolt of drive axle
Service Manual for G9180 Grader
4-35
assembly together with the tires out rapidly.
8. Use holder to support rear frame.
ATTENTION
Prior to step 6, you should check the
fixation condition of front tires again. Make
sure the front tires are reliably wedged to
prevent the vehicle moving forward when
lifting the rear frame. The lifting appliance
should be reliable.
Assembly drive axle
ATTENTION
When assembling, the mating surfaces
should be properly protected and cleaned,
to avoid intrusion of foreign matters.
The mating surface should be coated with
plane sealant according to related
requirements, the bolts should also be
coated with thread locking seat accordingly.
In the process of assembling, related
standards of tightening torque in this
manual must be strictly followed.
1. Connect lifting appliance to the tail of rear
frame, lift the frame up a bit.
ATTENTION
Before lifting the rear frame, you should
check the fixation condition of front tires.
2. Assemble the drive axle.
Push the drive axle assembly to the bottom of
rear frame, lower the frame slowly, align the
bolts holes, install and tighten the fixing bolts.
1
Fig. 4-58
1 Rear frame
Service Manual for G9180 Grader
4-36
940~1120Nm
3. Connect the transmission shaft.
110~130Nm
4. Connect the brake oil pipes on both sides of
the balancing box.
5. Connect the breather pipe.
436 Use, Maintenance and Repair of Drive Axle
In normal use, service condition of the components of drive axle is highly related to whether they
are being used, maintained and repaired properly. To keep the machine in good working condition
1 2
Fig. 4-60
1 Transmission shaft assembly
2 Bolt
1
Fig. 4-61
1 Brake oil pipe
Service Manual for G9180 Grader
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and extend its service life, the information, notes and precautions below should be taken as
reference when use, maintaining and repairing the drive axle.
1. Connection of rim and axle
Specification of the rim nut is M22×1.5, the tightening torque is 700~800Nm. The rim nuts should
be tightened symmetrically and equally. In normal use, you should regularly check whether the nuts
are loose and tighten them immediately if so. When ball faced rim nuts are used, you should check
whether the nut ball face and the ball socket are properly fitted, make sure the connection is
reliable.
2. Lubrication
2.1 Lubricating oil type GL-5 85W/90 Gear oil
2.2 Oil filling points and filling quantity
The filling port (an independent oil filling pipe) of main reducer and wheel reducer assembly is
designed on top of the main reducer. The oil level checking hole on both sides of the left and right
balancing box are also used for oil filling, keep the axle horizontal when filling.
Recommended oil filling quantity: filling quantity for main reducer and wheel reducer assembly is
about 28L, filling quantity for each balancing box is 23L.
When filling, a little overflowed oil from the oil level checking hole is allowed, the lower limit is
8mm to the hole bottom edge.
2.3 The joint of balancing box assembly and wheel reducer, and the balancing box assembly use
grease as lubricant. Inject grease into the grease nipples.
3. Use and maintenance
3.1 Clean up the oil dirt, dust and mud regularly. Note that the breather plug should always be
unobstructed. Check the fastening condition of each fastener, especially the connecting bolts of
main reducer, wheel reducer and rim, tighten them immediately if they are loose.
3.2 Periodically check the drive axle for oil leakage, eliminate failure as soon as possible. Check the
lubricating oil level in main reducer, wheel side reducer and balancing box, add if insufficient.
Initial replacement of lubricating oil: In the first month or after the first 100 working hours.
Periodic replacement interval of lubricating oil: Every six month or every 1000 working hours.
3.3 The joint of balancing box assembly and wheel reducer, and the balancing box assembly use
grease as lubricant. Inject grease into the grease nipples every three month.
4. Notes for maintenance
4.1 When overhauling the main reducer, smear test should be performed to check the gear meshing
zone. The meshing zone should be close to the small end in the axial direction, and its size in
Service Manual for G9180 Grader
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this direction should be ≥1/2 length of the tooth. In the radial direction, the meshing zone
should be in the middle area.
4.2 Wheel side reducer assembly adopts “castellated nut + fastening bolt” locking form.
When assembling, you should apply repair method to adjusting ring to adjust the axial clearance
between the bearing and wheel reducer housing to 0.05~0.15mm, and tighten the castellated
nuts to 500~600Nm, and make sure the chain wheel can rotate freely after that. Then, install and
tighten the fastening bolts to 60~70Nm. The two fastening bolts should be tightened
alternatively and equally. Make sure the fastening bolts have no protrusion to the end face of
chain wheel shaft.
4.3 Use selecting method to assemble the roller pins (in wheel reducer planet gear), diameter
difference between any two roller pins in the same group should be no more than 0.005mm.
Cylindricity of the roller pin should be no greater than 0.003mm. Radial clearance between the
roller pin and pin hole should be 0.015~.030mm.
4.4 When replacing or overhauling the axle shaft, make sure the clearance between adjusting pillar
and the stop block is 1~2mm.
4.5 Rated working pressure of the brake is 10MPa, and the maximum working pressure is 15MPa,
the brake fluid is mineral oil.
4.6 After the first working hours, the transmission trains should be inspected and tensioned when
necessary. Do this maintenance every 500 working hours thereafter.
Refer to Page 1-19 in 1 Repair & Maintenance for inspection and steps to tension the
transmission chain.
4.7 After maintenance, the mating surfaces that were originally coated with sealant should be
cleaned thoroughly, and should be recoated with a layer (1mm) of 598 plane sealant after being
dried. The bolts should be cleaned and dried too, and coat 262 thread locking sealant to the
bolts, and then tighten the bolts according to related requirements.
4.8 All seals and sealing gaskets should not be reused once removed.
4.9 Check the thickness of the friction plates through the observation hole, the brake shoe must be
replaced if the friction plate is worn to 3mm.
44 Diagnosis and Solutions for Common Fault of Transmission System
441 Common Faults of Transmission Box
Service Manual for G9180 Grader
4-39
Fault phenomenon Possible cause Elimination method
1. Low
transmission
oil pressure
1) Oil level in transmission box is
low
1) Add transmission oil to
specified level
2) Oil filter is blocked 2) Replace the filter
3) Control valve pressure valve
element is in seizure
3) Clean the valve element and
replace it if necessary
4) Transmission oil pump is faulty 4) Replace the pump
2. Transmission
oil pressure of
a certain gear
is low
1) The gear valve element is in
seizure
1) Clean the valve element and
replace it if necessary
2) The clutch has internal leakage
problem 2) Replace the clutch
3) Oil seal is damaged 3) Replace the seal
3. Unable to
engage a gear
1) Oil level in transmission box is
low
1) Add transmission oil to
specified level
2) The transmission oil pump has
severe internal leakage problem,
low efficiency
2) Replace the pump
3) Wire of gear valve is loose or
broken 3) Fasten or replace the wire
4. Overheating
of torque
converter and
transmission
box
1) The radiator is clogged or
damaged
1) Unchoke the radiator or
replace it
2) Oil level in transmission box is
low
2) Add transmission oil to
specified level
3) Long-time driving at high gear
or low gear
3) Change the habit, select
different gears when driving
4) The safety valve of torque
converter is faulty 4) Replace the valve
5) The transmission oil has gone
bad 5) Replace the oil
6) Slipping of clutch 6) Overhaul the clutch
5. Disordered
gears
1) The electric control signal is
incorrect
1) Check according to Table
4-2
2) The solenoid valve is in open
circuit or burnt 2) Check and replace the valve
3) The gear valve is in seizure 3) Overhaul and clean the valve
4) The gear clutch is sintered 4) Overhaul and replace the
valve
442 Common Faults of Drive Axle
Fault phenomenon Possible cause Elimination method
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4-40
1. The balancing
box produces
severe
abnormal
noise
1) Tensioning of the transmission
chain is inappropriate 1) Adjust
2) The transmission chain is faulty 2) Replace the chain
2. Overheating
of drive axle
1) Oil in drive axle is insufficient or
the oil has gone bad 1) Add or replace the oil
2) Main drive clearance is
undersized 2) Adjust the clearance
3. The drive axle
produces
abnormal
noise
1) Main drive clearance is
oversized 1) Adjust the clearance