【正文】 o splines n i put sh ft a d rotatesat sam speed rotatio i transferred to four pi io pla gears which rotat arou d an annulus g r R tatio of pla ry pi ion gears use front d rear carri rs o rot tear c rrier has g ar teeth which m sh w th the t eth n thes eve Plaary Gearset Pinion thrust washer Roller separator Pinion pla roller Pla pinion shaft Pla pinion gear Pinion thrust washer Fork and Rail Assembly Main ponent for changing from high to low ratio Driven by the stepper motor and gearbox assembly and the lead screw Stepper motor rotat s the lead screw which in turn moves the fork and rail assembly linearly in the front and rear casings Fork is posi iv ly l cated in stepped ring on the outer di meter of the synchro iser sleeve This linear movement is tra sferred to t e sle v which initiat s the range chang . Stepper Motor and Gearbox Assembly Electrically changes transfer box ratio from low to high and visa versa Four brush motor i controlled by PWM signals from t e transf r box ECU Wires from ECU are wisted to minimise electricalinterferenceH sing contai s mag e s, armature and bru h assembly, to op rat motor Armature shaft i adjust d for end float w th shims Motor housing Armature and brush assembly Shims Stepper Motor and Gearbox Assembly Toothed gear at opposite end of shaft mates with the reduction gearbox Reduction gearb x prises an annulus housing, ight plaary rs and a sun gear and carrier plate Drive shaft ssembly pri es a machin d shaft and amo n ng plate Mac ined roove in shaft times pote tiom ter to he position of th lead screw unting plate is lo ated o the ft n a pla n brassbearing, with a thrust washer between plate and boss on the shaft External h xagonal boss rovide location for the o e me r, preventing th housing from rotating A ho in connect r u pl es a 5V referenc upply, an u pu signal nd ground for th pot tiom ter. Reduction gearbox Annulus housing Plaary gears Sun gear Drive shaft assembly Mounting plate Potentiometer Torsen174。 Differential Unit is a full time torque sensing and biasing system Supplies 50:50 torque output to front and rear drive shafts during normal driving conditions Ablity to’bias’ torque t axle and wheels with high r grip Mus be achiev d with t causing wh el sl p to w eel with lower grip Torque biasing capability is in tantan ous and op rates as a preventative system Housing/ ring gear Side gear (front propeller shaft) Side gear (rear propeller shaft) Pinion gear Cover plate Torsen174。 Differential Housing/ ring gear Side gear (front propeller shaft) Side gear (rear propeller shaft) Pinion gear Cover plate Unit does not need wheel slip and speed differentiation to be activated Senses, via torque saturation, that on propeller shaft has the in ntion to rotate faster than the other one biases torque a ay from that propeller shaft and appliesit to th other Co v ntio al systems require wheel sli to occur first before ni a ing rque bi sing action Becau the unit reac s before slip ccurs, drivi g ac ion is very sm oth which results n enhanced grip for road wheels. Torsen174。 Differential Unit prises a housing, two side gears, six pinion gears, thrust and friction washers and a cover plate Ma n shaft ha cross drillings which supply lubricati g oil to e internal ponents Rotati n l input is pa sed directly to the synchroniser sleeve for high range r indirectly via the plaary gear set for low range Frictional forces between the pin on gears and the hou ng contributes to the opera ion of unit Pi ions re fitted in the housing in pposite pairs Axi l thrust applied o the side gears f rces gears i to act with tw of the thrust washers, c using a locking f the side and pinion gears under certain circumstances. Housing Side gear (front prop) Side gear (rear prop) Cover plate Transfer Box ECU Position of the ECU changes with LH and RH drive vehicles Connected on CAN bus and controls transfer box op ration using CAN messages from other ECU’s on the work ECU us s t ree connectors for all inputs and outputs Receives one perma nt power sup ly and an ignition supply via fuse 33Se ond feed, via ig itio swit h position I and f s 37,activat s neutral selection function Transfer Box ECU ECU memorises stepper motor position when the ignition is switched off When ignition i subsequently switched on, ECU powers tepper motor until lead screw drives fork and rail assembly against end stop for previous range th calibrates itself to thi pos tion and confirms that ele t d range is correct controls clo d loop p sition sensing sys em a d regulates the power supply to the motor to ensure optimum shift quality is cap bl of adjusting e performa ce of the ync roniser sy t m to roduce s oth and effortless inguses a rie of programmed hift maps control the ation spe d and ensure that a maximum hift time of seconds. 6/17/2021 7:57 AM 169。 Land Rover 2021. Presenter / File name Slide 113 Default/Limp Home Strategy If a fault occurs with the transfer box, the ECU or one of the required input signals, the ECU records an error code and the low range ’mountain’ symbol flashes permanently As a default setting, ECU will attempt to engage high or low range to allow the vehicle to be driven to a Lan Rover dealer for repair To ensure a range is engaged, gni ion must be switc ed ff and o again his causes the ECU to power the step er mot a d ngage the p viously elect d rang . Diagnostics ECU can store fault codes which are retrievable using TestBook/T4 Inform tion is municated via diagnostic socket Socket allow exchange of inform tion between various ECU’s n the bus systems and TestBook/T4 t the sock via a diagnostic ISO9141 K Line This allow the retrieval of diagnostic inf rmation nd programming of certain functions using TestBook/T