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Power Transmission Lubrication and Hydraulic Control System
The power transmission lubrication and hydraulic control system serves to disengage the engine clutch, to engage the friction members of the planetary steering gears, to make the shifting of speed gears easier, to lubricate the rubbing surfaces of bearings, gears, and also to engage the stopping brake bands.
The system incorporates the following units : oil pump 33, oil cleaner 34 (Hydraulic vortex tube), valve box 19, valve 15 for engine clutch smooth engagement, slide valve box 37, gear shifting servo-cylinders6 and 13, oil cooler17, by-pass valve 14 and pipelines.
The oil pump is used to deliver oil under pressure to the power transmission lubrication and hydraulic control system. It is mounted in the lower part of the gearbox and consists of a housing, drive gear and driven gear, reducing valve.
The hydraulic vortex tube is used for cleaning oil of mechanical impurities. It is located on the upper half of the gearbox, at the left and consists of a vortex tube, hopper and plug.
The valve box is designed to distribute oil flows, to maintain the required pressure of oil in the gearbox and planetary steering gears lubrication and hydraulic control system and to facilitate the control of the engine clutch. The valve box is located on the gear case upper part, and consists of body, and engine clutch control linkage slide valve.
Valve maintains an oil pressure in the hydraulic control equal to 0.76 to 0.93 MPa, and valve maintains an oil pressure of 0.25 to 0.3 MPa in the lubrication system. At the speed of 900 to 1000 rev/min, the oil pressure in the lubrication should be 0.1 MPa.
Valve 9 prevents the engine clutch from engagement during a short-time dropof oil pressure at the instant the servo-cylinders are being filled in the process of gear shifting.
The engine clutch smooth engagement valve is located on cover 25 and consists of body, ball valve 24, throttle-20 with filter 23 and plug 21.
The slide valve box is designed to control the friction members of the planetary steering gears and the stopping brakes. It is mounted on the gear case Upper half near the valve box. The slide valve box consists of body 27. LH turn slide valve 26, RH turn slide valve 29,stopping brake valve 11, back-moving spring 17 and levers.
The gear shifting servo-cylinders are designed to make 2nd- 3rd and 4th – 5th Speed gear shifting easier. They transmit and boost the effort from the gearbox control linkage des to the gear shift forks. The servo-cylinders are located on the upper half of the gear case. They are similar in design and consist of body 39, piston 36, Slide valve 34, index 40, coupling 37 and spring 33.
The oil cooler is of a fin-and-tube type and is designed for cooling of oil in the lubrication and hydraulic control system of gearbox. It is located in the ejector casing and is similar in design to the oil cooler in the engine lubrication system.
The by-pass valve is used to protect the oil coolers from high pressure in case of oilovercooling. It is located above the power-pack near the engine compartment bulkhead.
The by-pass valve-consists of a body, ball and spring. The valve spring is adjusted to open the valve at a pressure of 0.23 to 0.25 MPa.
Oil is supplied to the mechanisms in the gear case through bores and channels provided.
When the engineoperates and with the control levers set in neutral position, the oil pump delivers oil from the gear case through gauze filter 34, duct 39 of the gear case to the hydraulic vortex tube. The inlet groove of the hydraulic vortex tube is located along a line tangent to the cylindrical part of the hydraulic vortex tube. As-oil passes through the hydraulic vortextube, the mechanical impurities are thrown off to the tube walls under the effort of the centrifugal force, slide down and settle in hopper 37.
The cleaned oil is fed to the valve box.
Valve 7 becomes open under the pressure of oil and oil goes from cavity “ c ” through the pipeline into the oil cooler and then through cavity " d " to lubricate the planetary steering gear, bearings, gears, blocks of gear shifting forks and other parts of the gearbox. ‘
At the same time oil passes to the slide valve box.
When the boosters of the control system get filled, oil pressure in the cavity “ c ” decreases, and valve 7 actuated by spring 8 returns to its initial position and shuts the duct supplying oil for lubrication of the gear box and planetary steering gears. Operation of the valve ensures maintenance of constant oil pressure in the power transmission hydraulic control system.
Valve 4 functioning in the same way as valve 7 keeps the oil pressure in the gear box lubrication system.
Engine Clutch
The engine clutch is double-disk dry—friction clutch,The engine clutch is designed for :
(a) Disengagement of the engine from the gear box during the gear shifting and emergency braking of the vehicle.
(b) Smoothly setting the vehicle in motion.
© Protection of the engine and power transmission parts from breakdown when the load on the driving Sprockets is sharply increased.
Design of Engine Clutch
The engine clutch consists of driving members connected to the engine flywheel, driven members connected to the drive shaft of the gearbox, and a clutch disengagement mechanism
The driving members include support disk 19, driving drum 16, driving disk 20, pressure plate 22, pressure springs 15 and fasteners.
The driven members include two steel driven disks 21 with friction disks riveted and connected to them on both sides, and driven drum23.
The disengagement mechanism consists of annular cylinder 10, piston 11, radial thrust bearing 12 in special case 13, three back-moving springs 8, three double-arm levers 4, three forks 5, three adjusting nuts 6, three lock plates 7.
The bearing is lubricatedwith the use of lubricator 9.
Design of Engine Clutch Control Linkage
The clutch control linkage consists of pedal 45 and lever 33 mounted on the pedal bridge, rod 32 connecting lever 33 and lever 29 on the intermediate bridge, a rod connecting lever 13 with lever 17 of valve box 16 and slide valve 3 in the valve box.
To limit and adjust a travel of the engine clutch. The pedal is retained in the initial position with back-moving spring 43.
Operation of Engine Clutch and Control Linkage
Under the action of pressure spring 15 the engine clutch is permanently engaged, i.e ,its driving and driven parts rotate as one whole and transmit the torque to the gearbox shaft.
Under the action of three back-moving springs 8 piston 11 to gether with bearing 12 is pulled off towards the gear box
When depressing the engine clutch pedal, lever 33 of the pedal bridge turning through rod 32 and levers 29 and 13 of the intermediate bridge turns lever 17 which in its turn acts on the slide valve 3 of the engine clutch. The slide valve moves and opens the duct supplying oil to the disengagement mechanism booster. Oil enters cavity " a" of the booster under pressure, displaces piston 11 and through bearing case 13 acts on the double-arm levers 4. The leversturnround their axles, pull off pressure plate 22, and compresses the springs, as a result, the driving and driven disks are disjointed and the engine clutch becomes disengaged.
For smooth engagement of the engine clutch, release the pedal half way and keep it in the position for a while. In this case , the slide valve moves and opens the duct for draining oil through the smooth engagement valve. From the engine clutch booster oil goes to cavity of the smooth engagement valve, presses off ball valve 24 and flows into the gear case through channel "d “.
The pressure in the cavity decreases at a high rate, and the ball valve under the action of the spring shuts off the flow of the oil. Further flow of oil takes place through a small hole of throttle 20, which fact ensures smooth engagement of clutch.
When the use of the smooth engagement valve is not necessary, the pedal should be fully released at once. In this case the slide valve returns and opens the oil drain duct.
To disengage the engine clutch with the engine stopped (For example, if theengine is stopped with a speed gear engaged), depress the engine clutch pedal and turn handle 35 of the engine clutch cock counterclockwise. As a result, the compressed air will rush into cavity " a " of the booster from the pneumatic system.
Thus, the engine clutch can be disengaged in two ways : hydraulically and withcompressed air.
Adjustment of Engine Clutch
Tools, accessories and expendable materials : wrenches 107-12, 27-39, 19-22, flat-nosed pliers (in the driver's box), wire K0 1.4, feeler gauge (In the box for spare parts and tools ), appliance for cranking of engine (In the group SPTA set ).
Unscrew the bolts fastening .the ribbed plate of the hull and raise the plate unfit it is locked.
Install the appliance for cracking of the engine clutch access door and clutch housing above pointer 2 and remove them.
Cracking the crankshaft by the appliance set the engine clutch housing so that the spring sleeve located to the left from the stamping on the housing is in the centre of the engine clutch access door.
Remove the appliance from the engine clutch access door
Unlock and remove the bolts fastening lock plate 7 that locks nut 6.
Remove lock plate 7.
Undo nut 6 by 1 or 2 turns.
Insert a feeler gauge 6.7mm in size, into clearance A and screwing in nut 6 adjust the clearance between bearing case 13 and lever 4 so that the feeler gauge travels in the clearance with a slight play.
Without removing the feeler gauge from the clearance install lock plate 7 on nut6so that the holes in the plate align with the holes in the housing and secure it with bolts tightening them by hand.
Extract and again insert the feeler gauge into clearance A, in this case the feeler gauge, 6.7 mm in size, should be freely moved with a slight play, and a feeler gauge, 7mm in size, should be moved with a slight effort.
Secure the lock plate by tightening the bolts until the plate is pressed to the housing and then unscrew the bolts by 1 or 2 turns, in this case the lock, plate should be freely moved in the clearance between the holes and bolts.
Lock the bolts In pairs with wire.
Mount the cranking appliance and crank the engine so that the second stampingoccupies the position of the first one. Remove the appliance. Adjust clearance A according to the procedure mentioned above.
Install the appliance and crank the engine so that the third stamping occupies the position of the second one. Remove the appliance. Adjust clearance A according to the procedure mentioned above.
Install the engine clutch cover and housing above the pointer in place and secure them.
Reinstall the ribbed plate of the hull and secure it.
Procedure for fitting feeler gauge between bearing case and lever in the measurement of a clearanceA.
To check clearance A, see to it that the spring sleeve located to the leftfromthe stamping on the housing is set in the upper point and proceed as follows :
( 1 ) Bring feeler gauge, 6.7 mm in size, and then feeler gauge, 7 mm in size, from the left of the spring sleeve to clearance A. In moving the feeler gauge along the engine axis, adjusting nut 6 should have a slight axial displacement, which means that the feeler gauge is between the lever and bearing case.
( 2 ) Shift the upper end of feeler gauge to the right as shown by a dotted line on the diagram, and then shifting the feeler gauge downward, insert the feeler gauge into clearance A is between the lever and bearing case.
Lubrication of Engine Clutch Disengagement Mechanism Bearing
Tools,accessories : wrenches 10-12, 14—17, grease gun, hose, rod of grease gun, end piece, grease.
Unscrew the bolts securing the hull ribbed plate and raise the latter to set it in the locking position.
Unscrew the bolts fastening the engine clutch access door cover and remove the latter.
Turn bearing case 13 by hand so that lubricator9 is in the upper position.
Connect the hose of the plunger-type grease gun to the lubricator of the engine clutch bearing.
Pack grease ( About 60 g ) into the bearing of the engine clutch disengagementmechanism. Check 3 quantity of the packed grease against the divisions marked on the grease gun rod.
Disconnect the hose of the grease gun from lubricator 9.
Reinstall the engine clutch access door cover and secure it with bolts.
Reinstall the hull ribbed plate and secure it.
Gearbox
The gearbox is multiple-speed with permanently meshed gears and has five forwardand one reverse speeds.
The gearbox is designed :
( a ) To vary the torque on the driving sprockets and the vehicle speed.
( b ) Toenable reverse of the vehicle.
( c) To disengage the engine from the driving sprockets.
Design of Gearbox
The gearbox consists of the following main units : gear case 1, drive shaft 18 made integral with the bevel gears, lay shaft 14, main shaft 10, reverse speed intermediate gear 28 secured on axial 38.
The gear case incorporates two halves : lower and Upper. They are coupled with the use of studs and nuts.
Mounted in the lower part of the gear case is oil pump 34 with its drive and gauze filter 36.
The drive shaft is mounted in a roller bearing and two ball bearings. Fitted on the drive shaft splines are driven members of the engine clutch.
Shaft 19 of the oil pump drive is inside the drive shaft.
The lay shaft is mounted in three bearings : two ball bearings and a spherical roller bearing. Installed on the lay shaft are gears 15, 16. 17. 20. 22 and synchro-shift clutch13 Gears 17, 20, 22 are mounted on the shaft splines and gears 15 and 16. on the needle bearings.
The main shaft is installed in four ball bearings. Mounted on the main shaft are gears 2, 5, 6, 8, 9, 11 and two gear shift clutches 7 and 21. Gears 9 and 11 are installed on the shaft splines, and gears 2, 5, 6, 8, on the needle bearings.
Gear 28 is secured on axle 38 which in its turn is installed in two ball bearings. It is permanently meshed with gear 6 to provide the reverse rotation of the main shaft in the reverse speed. Gear changing is effected by shifting the clutches mounted on the splines of the shafts.
For easier and noiseless engagement of the 2nd, 3rd, 4th and 5th speed gears, the gear clutches are provided with inertia-type synchronizers which ensure. smooth meshing of the gear clutches by balancing the speeds (Engaged) gears with those of the lay shaft and main shaft.
Design of Gearbox Control Linkage
The control linkage is used for speed gear shifting in the gearbox by the driver.
It consists of gearshift lever 14 secured in steering column housing 26, shaft 28,
shifter shaft box 33, three rods 34, 36, 38, servo-cylinders 1 and 2, lever 41 and gearshift forks 39 and 42. The gearshift lever is mounted in frame 25 on axle 24. The lever fork enters the slots of shaft 28. The lever mount is covered by protective boot 23.
The shifter shaft box consists of housing, three shifter shafts 48, 50, 58 which mount couplings 45, gear-selector lever 54, ball lock 49 and three spring locks with balls 52.
Spring 56 sets shaft 28 in the position corresponding to the neutral position of the gear-shift lever,In this position the gear-selector enters the slot of the coupling of the 4th-and-5th speed gear shifter shaft.
The ball rock is used to prevent simultaneous displacement of two shifter shafts and, consequently, simultaneous engagement of two gears. The lock incorporates balls and locking 51.
The Spring locks are similar in design and are intended to retain the shifter shafts in the neutral position and in the engaged-gear position. When balls 52 enter one of three grooves available on each shifter shaft, they retain the shifter shaft in the desired position.
Operation of Gearbox and Its Control Linkage
The gearbox and its control linkage can be either in the neutral position or in aengaged-gear position.
In the neutral position gearshift lever 14 assumes the middle position in which it is retained by spring 56. In this case the shifter shafts are retained in the neutral position by the spring locks t Balls 52 are in the middle grooves of the shifter shafts ).
The speed gear shift clutches with the synchronizers ( Synchro-shift clutches ) and the 1st and reverse speed gear clutch remain in the middle position ( They are not meshed with the gears ).
Rotation is transmitted from the engine to drive shaft 25 through theengine clutch and further on to lay shaft 10 through the bevel gears.
Before shifting into gear, disengage the engine clutch.
To shift into the 1st Speed gear, pull gear shift lever 14 and turn it upward. In pulling the gear shift lever, shaft 28 shifts and gear-selector lever 54 enters the slot of coupling 45 of shifter shaft 58.
When the .gear shift lever is turned upward, the gear-selector lever shifts the shiftershaft which turns lever 41 through rod 38. Turning together with lever 41 the gearshift fork displaces gearshift clutch 7 by its blocks and engages the clutch with gear 8 and thus, the 1st speed gear is engaged.
To shift into the reverse speed gear.pull gear shift lever 14 from the neutral position and turn it downward. The gear shift fork is turned through the system of the levers and rods and engages gear shift clutch 7 with gear 6.
Because the principle of operation of the gearbox members during shifting into the 2nd, 3rd, 4th, and 5th speed gear is similar, examine their operation during shifting into the 2nd speed gear only.
To shift into the second speed gear, pull gearshift lever 14 and turn it upward. When the lever is pulled and turned upward, the gear-selector lever enters the slot of the shifter shaft shifts slide Valve 48 and displaces the shaft. The shifter shaft slide Valve 34 of servo-cylinder 2 through rod 34.
When the slide valve is displaced, piston 36 initially remains stationary because the effort applied to move gear shift fork lever 38 is not sufficient, spring 33 is compressed and channel “ e ” communicates with cavity “ a ” of the servo-cylinder. Oil presses on piston 36 which moves and displaces the lever 38. The gear shift blocks move synchronizer ring 4 towards gear 5.
Motion is further transmitted from the ring through four pins 23 to the gear clutch and then stops 25 to the synchronizer body. The synchronizer body moves until its tapered portion contacts the tapered collar of gear 5.
Due to the difference of speeds of the gear clutch and the gear to be engaged. Sliding friction force occurs between the tapered surfaces. Under the action of this force, the synchronizer body is drawn along by the gear being engaged and turns relative to the gear clutch until the wall of the synchronizer body ports rest against the gear clutch legs.
Oil remains in the booster and is drained into the gear case during disengaging the speed gear when the slide valve starts moving.
To shift into the 3rd speed gear, push the gear shift lever from the neutral position and turn it downward in this case the gear clutch teeth mesh with gear 2nd and the 3rd speed gear is engaged.
To shift into the 4th speed gear, turn the gear shift lever from the neutral position downward in this case the teeth of gear clutch 13 mesh with those of gear 9 and the 4th speed gear gets engaged.
To shift into the 5th speed gear, turn the gear shift lever upward, in this case gear clutch 13 engages with gear 11 and the 5th speed gear is engaged.
Check of Filling and Replenishment of Gear Case with Oil
Tools, accessories and expendable materials : tommy bar, extension, detachable head 27, attachment ( in the box for spare parts and tools ), funnel with strainer, waste, oil.
Clean plug 1 of dust and dirt and unscrew it.
Clean the place around the dipstick of dust and dirt and remove the dipstick.
If the oil level is below the lower mark on the dipstick, replenish the gearbox with oil, for which purpose, proceed as follows :
( 1 ) Wipe dry the dipstick with waste.
(2 ) Install the funnel with attachment and strainer into the hole of dipstick.
( 3 ) Replenish the gear case with oil until the oil level is against the upper mark on the dipstick.
Check the oil level in the gearbox not earlier than 15 min after the stop of the engine.
Install the dipstick in place so that the flat on the dipstick head comes behind lug on the cover.
Screw in plug 1.
Change of Oil in Gearbox
Tools, accessories and expendable materials : tommy bar, extension, detachable head 27, hose, wrench 765- 93-sb159, funnel with strainer, attachment, wire KO 1.4, bucket, waste, oil.
Clean plug 26 in the vehicle bottom of dust and dirt one unscrew it.
Clean the plug in the gear case of dust and dirt, unlock it and unscrew it.
Unscrew plug 1.
Clean the place around the dipstick of dust and dirt, extract the dipstick and wipe it dry with waste.
Prepare a container.
Screw wrench 765-93-sb159 into the gear case hole havingconnected a hose to the wrench.
Drain oil into the container.
Drive out wrench 765-93-sb159 and put it in the place.
Screw in plug 26.
Fill the air box with oil through the hole for the dipstick to the upper mark on the dipstick ( about 20 lts ).
Start the engine, run it for 3 o 5 mins and stop the engine. After 15 to 16 mins check the oil level in the gearbox and refill the gearbox with oil, if necessary.
Install the dipstick in place so that the flat on the head comes behind the lug on the cover.
Screw in plug 1.
Washing of Gearbox Hydraulic Vortex Tube
Tools, accessories and expandable materiel: : wrench 19-22, wire KO 1.0, diesel fuel.
Remove access door cover 11 having opened two locks fastening the covers.
Unlock plug 36 and unscrew it.
Wash the plug in clean diesel fuel.
Clean the internal surface of the vortex tube with clean waste moistened with diesel fuel.
Screw in the plug and secure it with wire. Before screwing in the plug make sure that a rubber ring is available.
Install access door cover 11 and secure it with locks.
Planetary Steering Gear and Brakes
The steering gears are planetary two-stage and designed to transmit the torque from the gearbox to the final drives, to enable the vehicle steer, and to increase the tractionof the driving sprockets for a short time without changing the gears
The vehicle is equipped with two planetary steering gears with stopping brakes similar in design. They are attached to the gearbox from both sides of the gear case.
The stopping brakes are band and floating type.
The stopping brakes are designed to stop the vehicle, to brake the vehicle, to make a sharp turn and to retain the stopped vehicle.
Design of Planetary Steering Gears
Each single gear consists of a single row planetary reduction gear, a steering clutch and a disk brake of the planetary steering gears. The planetary reduction gear incorporates epicyclic gear 19 installed on the gearbox main shaft, carrier 34 with three planet pinions 8 on their spindles, sun gear 35 is rigidly connected to outer drum 21 of the sun and epicyclic gear to have the low range.
The steering clutch connects epicyclic gear 19 to sun gear 35 to provide the direct transmission of the torque from the gear box main shaft to the final drive and disconnects the sun and epicyclic gear to have the low range.
The steering clutch consists of 4 driving disks 18 with metal ceramic friction surfaces, three driven disks 17, outer drum 21, pressure plate 7, pressure spring 20, a support disk and inner drum 19.
The steering clutch is permanently engaged.
The planetary steering brake is used to stop sun gear 35, to change the planetary steering gear to the low range.
The brake consists of disk brake 24, outer drum 23. an inner drum which is made integral with outer drum 21 of the steering clutch, pressure-plate 27, support disk 5, springs 26 and piston 28.
The planetary steering brake is permanently disengaged.
The stepping brake consists of brake band 53 composed of two halves to whose inner surface reinforced frictional linings are riveted, back moving springs whichare attached to brackets 10 and to the brake band, two hydraulic cylinders, springs 18, adjusting nut 52, lever 7, stop 6 and brake drum 54.
Design of planetary steering control
The vehicle steer control is used for turning the vehicle. It consists of handle bar 19 located in the steering column, shaft 20, levers 31 and 32, rods 10 and 37,levers 9 and 40, and slide valves 26 and 29 for the left and right turnings.
Movable stop 22 is rigidly attached to the shaft. Welded to the steeringcolumn tube is a plate which is provided with adjustable limiters 21 and 29. The movable stop and limiters preclude any possible striking of the slide valves against the slide valve box body when the handle bar is deflected to the maximum.
Pressed in shaft 20 are two lock pins 15 and 16 which enters the slots provided on the hubs of levers 31 and 32. When the handle bar is deflected, one lock pin thrusts against the edge of the slot and moves the lever, and the second lockpin moves along the slot of the second lever which is retained by the spring and does not turn.
The low range control is designed for simultaneous disengagement of the clutches and engagement of the brakes of both planetary steering gears When the vehicle is moving straightforward, which ensures an increase of torque by 1.44 times and consequently a decrease of speed at each speed gear.
The. control incorporates lever 18 located on the steering column,shaft 30 withlevers welded to it, rods 11 end 35 hinged With levers 9 and 40 of the turn slide valve.
Operation of Planetary Steering Gears and Their Control
The planetarysteering gear control can be in the in low range position with the low gear engaged and in the steer positions.
In the initial position, handle bar 19 is set horizontally, low range lever 18 is in the upper position, levers 9 and 40 of the slide valve box are retracted to the rear most position by springs 5 and 6, the steering clutches are engaged and the planetary steering brakes are disengaged. In this case, the sun gears of the planetary steering gears are interlocked with epicyclic gears, i.e., they move as a unit.
When a gear is engaged, the carriers of the planetary steering gears rotate at the same speed as the main shaft of the gearbox. The vehicle moves at a speed offered by the speed gear engaged in the gear box.
When lever 18 is shifted downward the slide valves of the slide valve box are moved through shaft 30. rods 11, 35 and levers 9, 40 and open the ducts supplying oil to the boosters of the steering clutches and planetary steering brakes.
Under the pressure of oil, the steering clutches are disengaged and the planetary steering brakes are engaged.
With a speed gear engaged, rotation from the gearbox main shaft is transmitted through the planet gears which roll over the sungears and rotate the carriers.
The vehicle moves straightforward at a speed which is 1.44 times lower than that offered by the speed gear engaged in the gearbox.
The vehicle is steered by deflecting handle bar 19 to the left or to the right, The radius of turn. vehicle turn changes smoothly, the greater the angle of deflection of the handle bar from the initial position. the smaller the radius of turn.
If the handle bar is deflected through a small angle to the left, lever 32 is turned through shaft 20 and turns lever 24 of the slide valve box through rod 37.
When lever 24 is turned, slide valve 26 displaces and opens the duct supplying oil to the booster of the steering clutch of the left planetary steering gear.
Oil under the action of gradually growing pressure owing to the bevel on the slide valve moves the pressure plate. The force compressing the disks decreases, and the date start slipping. As the compression force decrease, the magnitude of torque transmitted to the driven disks of the steering clutch of the left-side planetary steering gear, and consequently to the left-side driving sprocket decreases. As a result, the left-side track starts lagging behind, and the vehicle turns to the left over a big turning radius.
If the handle bar is deflected through a great angle, slide valve 26 moves and opensthe duct supplying oil to the booster of the left side planetary steering brake, in this case the duct supplying oil to the steering clutch booster remains open. Piston, together with pressure plate 27 starts to move and compresses the friction disks of the planetary steering brakes.
The clearance between the friction disks gradually decreases the disks starts slipping, the magnitude of torque transmitted to the planet carrier is growing and the left side track lags behind the right-side track more and more, and the radius of the vehicle turn will gradually become smaller.
With fully engaged steering brake and disengaged steering clutch of the left side planetary steering gear, rotation is transmitted to the planet gears which roll over the braked sun gear and rotate the lift side planetary steering gear carrier at a speed which is 1.44 times lower than that of right side planetary steering gear carrier, and the will turn with the fixed radius or turn.
When the handle bar is deflected up to stop, slide valve 26 moves additionally and initially opens the duct draining oil from the booster of the planetary steering brake. In this case oil drains into the gear case and the brake piston returns in the initial position and releases the friction disks. The steering clutch remains disengaged.
After this slide valve 26 opens the duct supplying oil to the hydraulic cylinder of the left side stopping brake.
The oil under pressure goes into cavity “ a “, piston 2 displaces and its rod 1 presses upon the roller of parking brake lever turns around its axle and clamps the brake band. The left-side track gets braked and the vehicle makes the left pivot.
When the handle bar is set in the horizontal position slide valves 26 moves in the initial position and Opens the duct draining oil from the steering clutch boosters in this case oil drains into the gear case and the steering clutch is engaged under the action of the springs. When the speed gear is engaged, the vehicle moves at a speed offered by the gear being shifted in the gearbox.
Stopping Brakes Control Linkage
The stopping brake control linkage consists of a pedal 38 located on the pedal bridge, in the initial position by spring 43, lever 34 on the pedal bridge, levers 12 and 28 on the intermediate bridge, rod 31. stopping brake slide valve 11 located in the slide valve box, hydraulic cylinders 19. The hydraulic cylinders are similar in design and each consists of body 3, piston 2, rod 1 and connections.
Operation of Stopping Brakes and Their Control Linkage
To brake the vehicle by the stepping brakes, depress pedal 38, in this case tube 46rigidly connected to the pedal and lever 34 are turned.
The lever is turned through the rod and moves slide valve 11 of the stopping brakes. The slide valve moves and opens the duct supplying oil to the hydraulic cylinders.
Oil under pressure enters cavity “ a ” of the hydraulic cylinders and moves the pistons and clamps the brake bands. The pressure in the hydraulic cylinders is gradually growing depending on a degree of depressing of the pedal, owing to the servo available.
In case the pressure of oil in the hydraulic control system is insufficient, clamping of the stopping brake bands is effected with compressed air supplied the vehicle pneumatic system. When the pedal of stepping brakes is depressed, the bridge lever acts on limit switch 30 and closes its contact. Voltage is supplied to the electro-pneumatic value of the pneumatic system through pressure warning unit 19, whose contact is automatically closed when the oil pressure in hydraulic control system drops as low as 0 25 MP and a limit switch. The electro-pneumatic valve opens and compressed air goes to cavity “ b ” on the hydraulic cylinder through the pipes and connections. Piston 2 moves and presses upon the roller of parking brake lever 7 and the stopping brake bands are clamped.
Design of Parking Brake Control Linkage '
The parking brake control linkage is designed to brake the vehicle when it is parked on a level ground, on a down grade and up-grade, and for slight braking of the vehicle it is being towed on the ground.
The vehicle is braked by clamping the left side stopping brake. Due to the fact that in straightforward movement the coupling shafts on the left and right sides are rigidly connected to the gear box main shaft through the planetary steering gear, steering clutches and rotate as a unit, the left side and the right side driving sprockets are braked simultaneously when the stopping brake band is clamped.
The control linkage consists of handle 3, shaft 2, retainer 12, limit switch 10, a rod, levers, bridges, back moving spring 67, with adjusting screw, and a rest located on the lower sloping armour plate of the hull.
Mounted In front of the drive is light panel RELEASE PARKING BRAKE which flashes after braking the vehicle with the parking brake and warns the drive on the necessity to release the parking brake before starting the movement.
Mounted in front of pedal bridge tube 46 is an additional bridge comprising shaft 41 levers 37, 40 and rod 36. The additional bridge is used when the vehicle is towed for a long time. In this case rod 36 is connected to lever 35.
Operation of Parking Brake Control Linkage
To clamp the parking brake band, pull handle 55.
Shaft 65 through the levers and rod turns lever 56 which acts on lever 7 of the stopping brake through the roller, the brake band is clamped and brakes the drum.
To retain handle 55 in this position the shaft is provided with slots. Under the pressure of spring 11 retainer 12 enters one of these slots.
While moving retainer12 presses uponthe ball which gets out of the recess and presses on the plate of limit switch 10.
The plate presses the micro-switch and the light panel RELEASE PARKING BRAKE comes on.
To return handle 55 to the initial position, turn the handle to the left and holding it bring the angle to the stop, and then turn it to the right and downward to the vertical position, in this case light panel RELEASE PARKING BRAKE goes out.
While rod 36 connected to lever 35 when pedal 38 of the stopping brake is depressed, shaft 41 of the additional bridge is turned and through rod 36 and the parking brake control linkage acts on the brake band. In this case shaft 65 with handle 55 does not move.
Check and Adjustment of Control Linkages of Stopping and Parking -Brakes
Tools and accessories wrenches 14-17, 13-14,detachable head 27, tommy bar, extension, feeler gauge, flat nosed pliers.
To check an adjustment of the control linkage of the parking and stopping brakes, pull the parking brake handle as far as it will go. If handle 55 provided behind retainer body 60 by 14 teeth or more, adjust the control linkage of the parking and stopping brakes in the following sequence.
Unscrew the bolt fastening the hull ribbed plate and raise it until it is locked by retainer.
Shift the parking brake handle so that lever 61 contacts stop 63.
Tighten up nuts 52 home. than loosen each by 8 turns.
Check the value of clearance l between lever 56 and the roller of lever 7 by a feeler gauge.It should be 0.3 to 1 mm. in case of deviation , adjust the clearance in the following way :
( 1 ) Unlock rod 64 having slackened nut 69.
( 2 ) Disconnect eye 58 from the bridge lever and driving in ( out ) the eye adjust the length of rod 64 so that clearance is equal to 0.3 to 1 mm is provided between lever 56 and the roller of lever 7. Connect eye 58 to the bridge lever and lock rod 64 with nut 59.
Reinstall ribbed plate, and secure it.
Final Drives
The final drive is essentially single stage planetary reduction gear.
The final drives are designed to constantly amplify the torque transmitted to the driving sprockets.
The final drives are attached to the hull sides in the front part of the vehicles.
Design of final drive
The final drive consists of housing 1 made integral with the epicyclic gear, input shaft 9 with the sun gear, three planet pinions 10, output shaft 8 and cover 2. Mounted on the input shaft of the left side final drive is speedometer drive driving gear 5. Inside the input shaft ,breather 23 is installed. A hole for filling the final drive with oil is provided in cover 2; the hole is closed with the plug 13. Oil level in the final drive is checked through the filling hole, Transmission of the torque from the planetary steering gear is effected through couplings 15 and shafts 16 and 18.
Operation of Final Drives
Torque is transmitted through shafts 16 and 18 from the planetary steering gears to the sun gears to the sun gears rigidly connected to input shafts 9.
Planet pinion 10 roll over the fixed epicyclic gears 1 and rotate planet carriers 8.
Torque is transmitted from the planet carriers to the driving sprockets.
At the same time a rotation is transmitted from input shaft 9 to speedometer driveshaft 6 through speedometer driving gear 5.
Check of Filling and Replenishment of Final Drives with Oil
Tools and accessories wrenches 14-17, 13-14,detachable head 24, tommy bar, extension, flat nosed pliers, lubricating gun.
Place the vehicle on the level ground.
Unscrew the bolts and raise the ribbed plate.
Unscrew plug 12 of the filling hole having unlocked it.
If oil does not flow from the filling hole.Replenishh the final drives with oil by the
lubricating gun until all comes out of the filling hole.
Screw in the plug of the filling hole and lock it.
Reinstall the ribbed plate and secure it.
Change of on in Final Drive
Tools.accessories and expendable material : extension. tommy bar, detachable heads17, 22, 27, flat-nosed pliers, lubricating gun, wire KO 1.0 and KO 1.6, bucket, waste, oil.
Place the vehicle on the level ground.
Unscrew the bolts fastening the ribbed plate and raise it to the stop.
Clean plug 12, 13 of filling and drain holes in the final drives of dust and dirt and unlock the plugs.
Prepare a container.
Unscrew plug 13 of drain hole and plug 12 of filling hole.
Drain oil into the container.
Screw in the plug of the drain hole and lock it with the wire.
Fill the final drive with the oil by a lubricating gun to the edge of the filling hole ( about 2 lts).
Screw in the filling hole plug and lock it in the wire.
Reinstall the ribbed plate of the hull and secure it.