Yanmar vio75 pdf

A distorted O-ring may not return to its original shape; therefore it may cause oil leakage. If reassembly is performed without cleaning such oil, it may be mistaken for oil leakage.

Notes : a When removing travel R 42 and blade 70 sections, carefully handle them not to lose springs 52 and poppets 51 on the mating surface. Notes : a Install wooden jaw covers when holding the valve housing with the bench vice to prevent damage to its mating surfaces.

Note : Each spool is only compatible with its valve housing. Mark the spools and their respective valve housings for identification. Note : Mark each poppets check valve and its valve housing not to get them mixed with any other one. Note : The spool is only compatible with its valve housing. Put the same identification marks on them. Procedure 12 Disassembly of anti-drift valve.

Hold body 18 with a bench vice to remove plugs 37 and 26 and the inner parts. Note : Install wooden jaw covers when holding the valve housing with the bench vice to prevent damage to its mating surfaces. Spring 57 is installed in cap 56 on one side of spool.

Note : a Install wooden jaw covers when holding the valve housing with the bench vice to prevent damage to its mating surfaces. Note : The spools 55 and 79 are only compatible with their respective valve housings 54 and Therefore, mark the spools and their valve housings for identification so as not to get them mixed with other ones.

Note : Install wooden jaw covers or other jigs when holding the spool assembly with the bench vice to prevent damage to it. Note : When loosening cap screw 49, take care not to get it jump out by force of spring 50 or Then place them in order on a clean piece of paper or waste cloth.

Inspect all the parts for burr, scoring, dent, wear or any other damage. Repair any damaged area by lapping. Replace any damaged spring with a new one. Reference data Free length. If any, make the mating surface completely smooth using fine lapping agent. Note : Clean the section with treated oil so that there should be no lapping agent left in the valve. Reference data Section. Repair any minor surface damage on the parts by lapping and remove all foreign substances from the grooves and passages in the parts so that they should move smoothly.

If a valve does not operate properly, replace it as a valve assembly. Notes : a Take care not to install the spool assembly in the wrong direction.

Tightening torque Then, install the plug 26 assembled in the step 5. Note : Take care not to install the spool in the wrong direction. This left-right asymmetry spool has a groove for identification in its top part. Procedure 9 Install poppet 20, spring 21 and spacer 22 with O-ring and backup ring to the valve housing. Note : Take care not to install the spool assembly in the wrong direction. Tightening torque 6.

Disassembly and Reassembly of Relief Valves 1 Disassembly and Reassembly Any of the relief valve must be replaced as an assembly in principle. However, only in an emergency case, the relief valve may be disassembled and reassembled. The contact surface must be uniform. If any defect is found in the above inspection, replace the whole relief valve assembly.

However, a defective O-ring can only be replaced with a new one. A distorted O-ring may not return to its original shape, and therefore, may cause oil leak. Note : Check the locations of the O-rings and the backup ring. Tightening torque : Then, remove spring 8, pilot poppet.

Note : Check the locations of the O-ring and the backup rings. Reference data: Pressure increment per turn of adjuster screw Circuit relief valve. Note : When adjusting the pressure of the circuit relief valve, first increase the pressure of the system relief valve to a value larger than that of the circuit relief valve.

Tightening torque for system relief valves and circuit relief valves. Note : The set pressure shows a nearly constant value even at full engine speed. Introduction 1 Foreword This manual deals with the instructions relative to servicing and maintenance operations for the hydraulic pilot control unit 4TH5 for the inspections and servicing operations associated with the hydraulic system of the machine to which they are connected. Please consult the maintenance manual supplied by the equipment manufacture.

It is recommended that only qualified personnel perform the installation, connection and maintenance of this device, and that all operations shall be carried out in compliance with the technical standards in force and the cleanliness regulations specific to this type of installation.

To ensure maximum performance and safety during maintenance operations we advise you to Read this manual thoroughly All information, illustrations, instructions and characteristics contained in this document are based on the latest product information available at the time of publication. They are indicated in the following manner: Indicates information or instructions which must be followed to guarantee your safety during operations.

Note : Useful information. Abnormal operation of equipment connected to the hydraulic pilot unit Malfunction. Fundamental Rules 1 General Information Concerning Pilot Control Unit Connection When removing the pilot control unit, all openings must be plugged immediately to prevent any contamination of the hydraulic system. When replacing the pilot control unit, remove the plastic plugs from the openings and lines just before making the connections.

Do not tighten connectors to a torque greater than that specified in the assembly instructions. The use of teflon tape, hemp and joint filler is prohibited. Hydraulic lines and connections must not be under any strain whatsoever.

No impurities must enter the hydraulic system. Plastic plugs are to be fitted on lines and orifices immediately following their removal. Wear protective clothing and use suitable equipment to prevent accidents, particularly concerning the hydraulic fluid. Set all actuators connected to the machine in neutral position on the ground, at lower limit With the machine off, release the pressure remaining in the system by manipulating all of the distribution spools. This is performed by moving the handle in all directions.

Make sure to collect any possible oil leakage in a suitable receptacle. Unscrew the mounting screws and remove the control device. Check the evenness of the support area on the machine tolerance : 0. Check the condition of the line connector seals. Clean the pilot control unit if it has been in storage for a long period of time. Ensure that the hoses are not twisted or rubbed. Once correctly installed, the unit can be placed into operation.

Remove worn out push button s using a small screwdriver. The installation of new elements is performed without any special tools ; the parts are simply pressed into place. Hold the pilot control unit using a vice or a vice-grip wrench clamp onto the body above the arm rest, 65 opening. Note : The pilot control unit does not need to be removed from the machine to release the cable. However, it is recommended to lift the control unit by undoing the 4 fixing screws on the arm rest.

It is unnecessary to remove the units without electrical functions. Handle removal Lift and turn the boot inside out. Remove the grommet from its emplacement to free the cable. Loosen the handle mounting nut 19 mm open-end wrench. Boot replacement Remove the faulty boot and replace it with a new boot. Replace the handle following the disassembly instructions in reverse order. Procedure Handle replacement Clamp the threaded section of the bent lever in a vice fitting with V-shaped vice clamps.

Remove the pin 5 mm pin driver. Remove : - pin, - bent lever, - handle. Replace the nut on the threaded section and replace the boot. Screw the handle onto the pilot control unit and tighten the nut 19 mm open-end wrench. Fit the grommet into its emplacement while leaving enough cable length so as to enable the correct handle operation. Secure the pilot control unit in a vice clamp onto the body.

Remove the handle. Note : It is recommended to remove the pilot control unit from the machine. Nevertheless, the servicing on machine is possible by securing the unit into a vice-grip wrench 65 opening. This is performed by extracting the body from the arm rest so as to clamp the vice-grip wrench onto the body in order to hold it above the arm rest. Removal of the cardan Fit an Allen wrench into the assembly screw and unscrew it 8 mm Allen wrench. In neutral position, the depression of the plungers must not exceed 0.

In order to check this value, observe the displacement of the plunger located opposite to the one being pressed. Note : The pre-depression may be difficult to achieve on site. Could be necessary to readjust it after reassembly and system working control. Remove the cardan.

Removal Secure the pilot control unit to a vice. Remove the retaining plate. Reassembly : Line up the notches for the grommet in both the plate and the body. Insert the end of a thin screwdriver between the guide and the body, carefully lift the guide to remove it from the body. Note : Hold the guide with the other hand during the extraction operation to limit the effect of the return spring.

Repeat the operation for the other 3 sub-assemblies. Reassembly : Use the retaining plate to insert the 4 guides into the body simultaneously and perpendicularly. Reassemble in reverse order. Regulation unit verification Extract the regulation units from the body using flat nose pliers. If defects are present, replace the 4 sub-assemblies.

Inspect the regulation units and particularly their spring. If defects are detected, replace the 4 units. Structure and Functions The swing motor consists of a swash plate type axial piston motor, a mechanical brake, a relief valve, make-up valve, a by-pass valve, a hydraulic timer and a planetary double-reduction gear. The rotary group of the piston motor consists of a cylinder integrated with a drive shaft and seven pistons located in the cylinder. The cylinder is supported by bearings at both ends.

The piston is guided by a return plate and a piston spring, which ensure that the piston moves smoothly along the cam plate. The balance plate is pressed against the end face of the cylinder by hydraulic pressure, which works on the wave washer and the bush. The relief valve to relieve excessive pressure cushion relief and the make-up valve for preventing cavitation are housed in the cover. The mechanical brake, which consists of a steel plate and a friction plate, is additionally installed between the cylinder and the housing.

Theory of Operation 1 Hydraulic Motor Hydraulic oil supplied from the pump through the control valve is taken in from the port A port B and is discharged from the port B port A.

The oil drained from each sliding part and the clearance is returned through the drain port A to the tank. Hydraulic oil supplied to the port A and fed to the piston passes through the passages B and C, the lunate-shape port D on the balance plate, and the passage E in the cylinder. When the hydraulic oil pushes against the piston, the piston is pressed against the cam plate swash plate through the shoe.

The pressing force the piston received from the hydraulic oil is transmitted to slide the shoe on the sliding surface of the swash plate. This sliding force is transmitted by the piston and the cylinder to the motor output shaft as rotating force. Thus, each piston moves along the swash plate to receive the force from the hydraulic oil during its stroke from the bottom dead center to the top dead center.

The hydraulic force is converted to the rotating force that rotates the cylinder. The oil is then discharged through the port B during the stroke from the top dead center to the bottom dead center.

When there is no pressure at the brake release port, the coil springs press the brake piston downward to force the friction plate against the steel plate, causing the cylinder shaft to lock. When At this time, if the upperstructure is swinging at relatively high speed, the swing motor is rotated due to the inertia force of the upperstructure, pumping begins, the pressure in the passage C becomes negative, and this requires oil supply.

If the pressure at the port B is lower than the cushion relief set pressure, all the oil that flows through the port A into the passage C is discharged from the port B to the control valve.

Thus the amount of oil from the control valve is less than the amount needed in the passage C. To prevent cavitation, oil is supplied from the tank through the make-up port and the make-up check valve to the passage C. The swing motor is rotated by the inertia force of the upperstructure. At this time, the pressure at the port B increases and the relief valve operates. The oil from the relief valve passes through the passages G and H, pushes and opens the make-up check valve on the port A side, and flows to the passages B and C.

The amount of oil is short by the amount of oil drained. To prevent cavitation, oil is supplied from the tank through the make-up port and the make-up check valve to the passages B and C. The oil supplied to the port A pushes against and opens the poppet, opposes the force of the spring of the relief valve, and flows through passage I to passage H. Some of the oil pushes against and opens the make-up check valve to flow to the port B.

At this time the pressure at the port B increases. The increased pressure at the port B overcomes the force of the spring of the relief valve to press and open the poppet, and flows through passage G to passage H.

This force also presses and opens the make-up check valve, and allows oil to flow to passage C to absorb the inertia energy of the upperstructure. Stage 1. While the pressure at the port B increases, the oil from the port B flows through the orifice A of the poppet, the orifice B and the passage C of the piston to the piston chamber to move the piston to the left until it contacts with the sleeve. As the poppet has been opened during this process, cushioning starts at a lower pressure at first and the pressure rises to the specified value in an instant.

Stage 2 The shock due to starting and stopping the motor is reduced by incorporating the function of two stages. This causes the motor to act like a pump to increase the pressure at one port A. The pressure stops swinging the upperstructure once but then rotates it reverse, and repeats such reverse swinging several times until the pressure sufficiently decreases.

The by-pass valve is normally closed but when reverse swing pressure is developed and makes specified amount of high pressure oil flow to the other port for specified time to prevent increase of the pressure at one port, so that the reverse momentum can instantly be reduced. If such pressure is developed in the port B, the high pressure oil flows into the back chamber on the B side of the check valve through the orifice b2 to move the check valve to the right and the bypass port b1 is closed.

This causes the upperstructure to stop swinging once but instantly begin to swing reverse. The pressure in the back chamber on the A side should increase and move the check valve to the left instantly but the oil flow into the back chamber on the A side is delayed a little due to the orifice a2 so that the movement of the check valve to the left is also delayed.

During this time, the oil from the port A flows to the center chamber through the bypass orifice a1 to move the check valve to the left and flows to the port B through the bypass orifice b1, then the check valve is moved to the left to close the bypass passage. While the reverse swing pressure is developed, the high pressure oil flows to the other port not to trap oil in the circuit. That is the way that reverse swing momentum is absorbed and the upperstructure stops swinging smoothly.

Reduction Gear 1 Structure and Functions Power is transmitted from the hydraulic motor output shaft through the first level sun gear 12, shaft AS1 18, and holder 19 to the second level spur gear 4 Power is similarly transferred through spur gear 4 11, shaft 20, and the second level spur gear 5 21 to the pinion shaft 1. The pinion shaft 1 is supported by two bearings 4 and 8 in the gear case. To protect the bearings on the pinion shaft side, which must withstand heavy loads, from powder dust generated by worn gears, the oil seal 7 is installed in the center of the gear case 5.

Compartments A and B are lubricated with gear oil and grease, respectively. Hydraulic Timer 1 Outline The hydraulic timer has the following function. The oil trapped in the chamber is gradually returned to the port D due to the pressure reducing function of the poppet and works as a timer.

Disassembly and Reassembly 1 Jigs 1 Swing motor Unit : in. Note : Mark each relief valve and bypass valve to aid in assembly. Procedure 9 Remove springs 14 from brake piston Note : Mark each spring to aid in assembly.

Procedure 12 Remove cylinder assembly from housing Note : Discard oil seal 35 and replace it with a new one. Procedure 15 Install a gear puller on inner race of taper roller bearing 1 and spline end of cylinder 16 to remove bearing with collar Note : Be careful not to damage sliding surface of cam plate.

Note : When reassembling the sliding parts, apply clean hydraulic oil to them. Jig : Taper roller bearing press fitting jig for inner race. Procedure 9 Apply Three Bond to outside surface and grease to lip of oil seal 35, and install it with a press fitting jig.

Apply Three Bond white or its equivalent. Procedure 13 Install O-ring 6 into housing 21 and O-ring 44 on to piston Note : Apply grease to O-rings. Note : Press the whole piston 15 with it level as it has interference for O-rings 6 and 44 and is hard to assemble. Note : Each spring should be installed in the same position as it was assembled in the factory. Procedure 21 Install cover 28 onto housing 21 slowly while holding balance plate 7 with both hands.

Note : Align positions marked before disassembly. When it does not rotate, disassemble it again for inspection. At that time, the drain port should be opened. Note : The planetary carrier cannot be disassembled because each shaft 1 18 is caulked to holder Procedure 5 Remove ring gear 10 from gear case 5 while prying up ring gear 10 by inserting a screwdriver or the like into the notch of gear case 5. Press shaft end to remove shaft 1 collar 2, plate 3 and taper roller bearing 4 as an assembly.

Grease : Albania EP2 or its equivalent Quantity : 9. Apply Three Bond or its equivalent as liquid packing to outside surface of oil seal 7. Note : Apply grease to lip of oil seal 5 after installation.

Note : Install a seal protector not to damage lip of oil seal 7 by spline of pinion shaft 1. Adjustment procedure : Install adjusting collar 0.

Procedure 10 Install bush 24 into spur gear 5 Install it with thrust plate 25 into 2nd planetary gear carrier and insert shaft 2 Note : Apply gear oil to inside surface of gears, inside and outside surface of bushes and outside surface of shafts. Slowly rotate the carrier to mesh its gears with spur 4 11 to install the carrier. Procedure 15 While engaging sun gear 12 and spur gears 2 26, install the sun gear to 1st planetary gear carrier.

Note : Check that pinion shaft 1 rotates smoothly when 1st planetary gear carrier is rotated. If almost all of the oil supplied to the motor is drained, disassembling and checking the motor is required because the sliding part may be damaged.

Open the output and input ports of motor, apply a pressure of If the output shaft does not rotate smoothly at the torque described on the left, disassembling and checking the motor is required because the motor internals may be damaged.

If the amount is 1. Open the output and input ports of motor, supply If the output shaft does not rotate smoothly at the torque described on the left, disassembling and checking of the motor is required because the motor internals may be damaged. If any metal foreign substances are found, disassembling and checking is required the motor because the motor internals may be damaged. Check the piping fittings, metal mounting bolts, motor mounting bolts, and each bolt of the motor for looseness.

Check the parts listed as the items a to e in Table 1 and the bearing, and replace them if any abnormality is found. Check the oil drained from the motor and drain filter for metal foreign substances. Apply a pressure of If metal foreign substances are found or if the output shaft does not rotate smoothly at torque described on the left disassembling and checking is required because the motor internals may be damaged.

The pressure in the case must be If the amount of drained oil is large, disassembling and checking the motor is required. The product contains a reduction gear, hydraulic motor, brake valve and parking brake in one compact unit. The reduction gear reduces the high speed of the hydraulic motor and converts it into low-speed, high-torque rotation.

It provides smooth stopping, prevents runaway rotation of the hydraulic motor and prevents the generation of abnormally high pressure when the hydraulic motor is stopped suddenly. It switches the hydraulic motor displacement between large and small.

Movement This reduction gear is composed of a spur gear unit hereafter referred to as the first reduction unit , and a differential gear unit using pericycloid gears hereafter referred to as the second reduction unit. Operating Description 1 First reduction unit [1] The high speed rotary movement of the hydraulic motor is output from the shaft This rotary motion. The input gear 6 meshes with three spur gears 7.

The speed of the spur gear 7 is reduced, and the direction of rotation is reversed. The reduction system of the input gear 6 and spur gears 7 Shaft This rotation causes the. This eccentric movement is transmitted through a needle bearing 23 to the RV gear 4. In this manner the RV. As RV gear move with eccentric motion, the meshing point moves. With one cycle of eccentric motion, each pin 17 moves by the difference [Zp-Zr] between the number. The hub 1 rotates in the.

The rotation of the hub 1 is the output rotation. The reduction in speed produced by the crankshaft, RV. Thus, for each rotation of the hydraulic motor shaft, the output rotation of the total reduction gear reduction ratio [i] is expressed as follows.

Motion 1 Hydraulic motor This hydraulic motor is a swash plate type axial piston motor, converting the hydraulic force from the pump to rotary motion. This is done by preventing hydraulic cavitation. A friction plate type mechanism is used, constructed so as to form one unit with the hydraulic motor. Operating Principles and Description. Force F is separated into components F2 and F3 accord-. This rotary force passes through the pistons and.

The following description assumes that the working fluid hydraulic is fed through port A. If the fluid is fed through port B, the flow and motion are reversed. The direction of rotation of the motor is also reversed. The details are as follows. First, the hydraulic fluid fed from the pump enters at port A and opens the valve The fluid oases through the valve , enters the hydraulic motor through port C and applies rotary force to the hydraulic motor. At the same time, hydraulic fluid enters at port A and passes through small holes in the spool and through channel a to chamber b.

The hydraulic pressure in chamber b causes the spool to move from the central position to the right. At this time a groove in the spool forms a channel for hydraulic fluid to pass between port D and port B.

Hydraulic fluid ejected from the hydraulic motor flows from port D to port B, and the hydraulic motor rotates. The hydraulic fluid returns to the oil tank. Also, as the spool oscillates to the right, hydraulic fluid enters port E. The hydraulic fluid at port E flows to the parking brake and 2-speed switching valve. At the same time, the hydraulic motor will rotate by the inertia even if the pressure is shut off, so the port D will rise the pressure. This pressurized oil goes from chamber f to chamber g through the right-hand valve When the oil enters chamber g, the piston slides to the left so as not to rise the pressure, as shown in the figure.

Meanwhile, the right-hand valve is pushed open by the pressurized oil in port D. Therefore, the pressurized oil in port D flows to port C at a relatively low pressure, controlling the pressure in port D and preventing cavitation in port C.

When the piston reaches the stroke end, the pressure in chamber g and f increases and equals to the pressure Spool in port D. The right-hand valve closes again, allowing the oil pressure in port D to increase further. Then, the left-hand valve opens port C with pressure higher Spring than that machine relief set pressure. In time, the pressure in port D is dropped by the decrease of the inertia. The left hand valve closes again, and the hydraulic motor is brought to stop.

In this way, by controlling the pressure in port D in two steps, the hydraulic motor is smoothly braked and brought stop. For example when used as the drive motor for a excavator, racing can occur when the vehicle Parking brake. The pressure of the hydraulic fluid feed at port A or port B falls. As the pressure approaches the level at which racing begins, the spool begins moving to the center towards the central position.

The movement. This restricts the amount of hydraulic fluid ejected from port D to port B. At the same time the pressure at port D back pressure increases. Thus racing is prevented by controlling the flow rate and. At this time the spool is pressed the left side by the force of the spring , the pressurized oil supply at port F is shut off.

The oil in chamber S is released into the motor case through the spool The force of the piston is. The swash plate is parallel to side Y. At this time the swash plate is tilted at a maximum. At this time the pressure overcomes the force of the spring and the. The pressurized oil supply from port F is then introduced into chamber S Piston The force of the piston is increased by the pressurized oil of chamber S. The piston pushes the swash plate up until it touches side X.

The movement of the spool opens port E. The hydraulic oil is fed from port E to cylinder chamber c. When the hydraulic pressure reaches PSI 4. The piston moves in the direction of the rear flange The pressure from the piston on the mating plates and the friction plates disappears, and the friction plates is able to rotate freely.

The friction plate is locked to the cylinder block of the hydraulic motor. Thus the braking force of the cylinder block is released, and the hydraulic motor is able to. The pressure in cylinder chamber c falls.

When this pressure falls below PSI 4. The spring causes the piston to press against the mating plates and friction plates This pressure creates the friction that serves as the braking force. The cylinder block is locked with the shaft of the hydraulic motor. Thus brake torque is applied to the hydraulic motor while.

Serious injury may result. Mounting bolt torque Quantity. This is to prevent entry of dust, welding scale, etc. Coverings should be removed before connecting tubing. Refer to Diagram of External Dimensions. Failure to do so may result in reverse rotation, or injury. Note : Before operating the motor, always fill the motor casing with hydraulic fluid. Required oil volume in casing. Otherwise, failure to do this may result in early damage to the hydraulic motor. Operating temperature range. However, it was abolished in March, Please use other viscosity grades as much as possible.

CAUTION Except for confirmation of the following three abnormal sounds, maintenance and inspection must always be performed when the product is stopped. Inspection during operation may cause injury or burns. Touching or approaching the product during operation may cause injury or burns. To prevent burns, use a thermometer to measure temperature and do not touch directly with the hands.

Additive types vary according to manufacturer. Gear Oil Change Interval [1] First change initial change after starting operation after hours [2] Second and following changes : after hours or one year Avoid mixing different types of lubricating oils. When changing the type of lubrication oil, be sure to flush the interior of the reduction gear. Gear Oil Change Volume 1. Gear Oil Change Procedure. Touching with the hands may cause burns. Also, removing port plugs while hot may cause hot oil to spray out as pressure is reduced in the reduction gear, possibly causing burns.

Also, take care to observe applicable laws and regulations regarding disposal. Turn the plug slowly and allow internal pressure to escape before removing. To fill oil, do not remove the plugs from the drain ports. After draining the oil, replace the plug on the oil drain port. Stop filling just before the gear oil overflows at the oil level check port. To be used for inserting removing coil spring , washers and snap ring into from cylinder block To be used for removing oil seal and coller 11 from spindle 2.

To be used for removing ball bearing 21 from hub 1. Bearing pre-load adjuster To be used for pushing ball bearings 21 when installing it in hub 1. To be used for measuring axial clearance between hold flange 3 and ball bearings Nut M If a parts slips out of your hand and falls, it could result in bodily injury or could damage the parts.

Be very careful when handling. These combustibles are easily Ignited, and could result in fire of injury. Handle with care and be sure not to hit the parts together or drop them. You should exercise patience when working.

If you have to interrupt work before completion, be careful to take measures to protect against rust or dust. All pages are printable. After your payment, you will have instant access to your download. We will always try to get the full satisfaction of our customers. Even after you have purchased this manual, we will pay full attention to any issues, regardless of the nature of the situation.

Control in swing motor mechanical brake release pilot line The oil discharged from the cut-off valve is supplied to each of the swing, arm, boom swing, and bucket sections through the port i7, and flows back to the hydraulic oil tank.

When one of these sections is actuated, the spool blocks the oil and the pilot pressure is caused. The pilot pressure flows through the port i8 to the port SH of the swing motor mechanical brake to open the swing brake release valve.

Therefore, the swing motor mechanical brake is not released before any of the swing, the arm, the boom swing, or the bucket is operated. Combined oil flow for boom up operation When the pilot oil for boom up operation flows to the port i4, the spool of the boom 2 section is moved, and the oil from the gear pump P3 flows through the parallel passage to the boom section to combine with the oil from the piston pump P1.

Combined oil flow for arm operation As long as all the sections upstream the arm section for the piston pump P2 and the gear pump P3 are in neutral, all the oil from the pump P2 and that from the pump P3 are combined in the arm section, and the combined oil flows to the arm cylinder. However, when the boom or bucket section of the piston pump P1 circuit is operated, some of the oil from the gear pump P3 flows to that section; therefore, not all the amount of oil from the pump P3 is combined.

However, when boom up and arm retract are operated simultaneously, the pilot oil pressure for the arm retract operation is led to the port i5 and moves the spool of the boom 2 section back to give priority to the arm retract operation. Non-deviation travel The oil from the pilot pump P4 flows to the port i6, then flows in parallel through the travel L section and the boom and bucket sections, and returns to the hydraulic oil tank.

When the travel L section is operated and simultaneously the boom or bucket section is also operated, the pressure develops in the circuit from the port i6 and the spool of the parallel-flow divider section is moved. At that time, the oil from the gear pump P3 is divided at the parallel-flow divider and supplied to the swing section, the arm section and the boom and bucket sections. Consequently, even when the oil from the piston pumps P1 and P2 flows only to the travel R and travel L sections, respectively, in the most upstream for the pumps P1 and P2, the swing, the arm, the boom, or the bucket can be operated.

In other words, the machine can travel with no deviation even when any of the control levers are moved during the traveling of the machine. Relief valve set pressure 1 Tightening torque The track shoe must not be attached here at this time. Note : 1. When connecting, connect so that the pressure gauge main circuit can be mounted and drain volume of the hydraulic motor can be measured. When mounting the GM motor, do not strike with a hammer, etc.

Pre-load preparatory operation Perform preparatory operation until approximately the following temperatures. Confirmation test Measure the following items to decide with the motor passes of fails the test. Passing criteria GM motor drive pressure : Max.

Engine oil alarm lamp Water temp. Not used in Europe.