Transmission 1 GEAR BOX OPERATION University Kuala Lumpur

Transmission 1 GEAR BOX OPERATION University Kuala Lumpur Malaysia France Institute Diploma in Automotive Maintenance

Transmission 1 INTRODUCTION • Gear box is an assembly of gears and shafts that transmit power from the engine to the drive axle • Generally uses driver operated clutch for regulating torque from engine to transmission and hand operated gear shift mechanism University Kuala Lumpur Malaysia France Institute Diploma in Automotive Maintenance

Transmission 1 Purpose • Be shifted into neutral for engine starting and running without turning drive wheels • Be shifted into reverse • Provide various torque needed to move vehicle under variety of load and road condition • Transmit power from engine to drive wheel University Kuala Lumpur Malaysia France Institute Diploma in Automotive Maintenance

Transmission 1 Type of gear box / transmission • 4 type of gear boxes / transmission 1. Sliding-mesh or crash-mesh • Basic layout of 4 -speed and reverse gearbox consist of various spur-type gears that mounted on three shafts. • Disadvantages of sliding-mesh or crash-mesh gear box i – Gear noise due to the type of gear ii – difficulty of obtaining a smooth, quit and quick change of gear University Kuala Lumpur Malaysia France Institute Diploma in Automotive Maintenance

Transmission 1 Type of gear box / transmission University Kuala Lumpur Malaysia France Institute Diploma in Automotive Maintenance

Transmission 1 Type of gear box / transmission 2. Constant-mesh (male and female attach with sliding mesh) • Use a stronger helical of double helical gears which lead to quieter operation. • Various size of gears revolves freely on needle bearings and in constant engagement with other gears on layshaft (counter shaft) • Gear operation obtained by locking the respective gear to main shaft by means of dog clutch. University Kuala Lumpur Malaysia France Institute Diploma in Automotive Maintenance

Transmission 1 Type of gear box / transmission University Kuala Lumpur Malaysia France Institute Diploma in Automotive Maintenance

Transmission 1 Type of gear box / transmission 3. Synchro-mesh (additional components are blocking ring). • Fundamentally are same as constant-mesh with the additional of a cone clutch that fitted between the dog and gear members. • Initial movement of selector sleeve carries the hub towards the gear and allows the cones adjusts the speed of the gearwheel • Extra pressure applied on lever allow the sleeve to override spring-loaded balls and engage with the dogs on the gear. University Kuala Lumpur Malaysia France Institute Diploma in Automotive Maintenance

Transmission 1 Type of gear box / transmission University Kuala Lumpur Malaysia France Institute Diploma in Automotive Maintenance

Transmission 1 Type of gear box / transmission 4. Epicyclic type (automatic transmission) • consists of one or more outer gears (planet gears), revolving about a central (sun gear). • planet gears are mounted on movable arm or carrier which itself may rotate relative to the sun gear. • also incorporate the use of outer ring gear or annulus, which meshes with the planet gears. University Kuala Lumpur Malaysia France Institute Diploma in Automotive Maintenance

Transmission 1 Type of gear box / transmission University Kuala Lumpur Malaysia France Institute Diploma in Automotive Maintenance

Transmission 1 Gear shift mechanisms • Shift fork are used to control movement of synchronizer • Shift rails transfer motion from driver controlled gearshift lever to the shift forks • Gearshift lever is connected to shift forks by means of a gearshift linkage University Kuala Lumpur Malaysia France Institute Diploma in Automotive Maintenance

Transmission 1 Gear shift mechanisms University Kuala Lumpur Malaysia France Institute Diploma in Automotive Maintenance

Transmission 1 Locking and locating devices • Locking device – prevent the selection of more than one gear during operation • As shift rail moves, locking pin moves out of its locking device and goes to other shift rails detent University Kuala Lumpur Malaysia France Institute Diploma in Automotive Maintenance

Transmission 1 Locking and locating devices • Locating device – hold the transmission in the selected gear • As shift rail moves, a detent ball moves out of its locating device and drops into the locating for the selected gear University Kuala Lumpur Malaysia France Institute Diploma in Automotive Maintenance

Transmission 1 Synchronizers • To prevent gear clash during shifting while the car is in motion • To ensure that gears and sliding sleeve about to mesh rotate at the same speed, so they will engage smoothly University Kuala Lumpur Malaysia France Institute Diploma in Automotive Maintenance

Transmission 1 Synchronizers University Kuala Lumpur Malaysia France Institute Diploma in Automotive Maintenance

Transmission 1 Synchronizer operation • As synchronizer sleeve is moved toward the gear, its slides on the hub splines and carries the three keys with it. • The keys move up against the synchronizer ring and push the ring towards the gear and bring the cone surface on ring into contact with cone surface on gear. University Kuala Lumpur Malaysia France Institute Diploma in Automotive Maintenance

Transmission 1 Synchronizer operation University Kuala Lumpur Malaysia France Institute Diploma in Automotive Maintenance

Transmission 1 Synchronizer operation • Further sleeve movement increase friction between ring and gear and brings the two into synchronous rotation. • As external teeth on synchronizer ring and gear rotate on the same speed, sleeve can easily slides on it and lock it into gear. • Power now flow from counter gear, synchronizer sleeve and hub, to the output shaft. University Kuala Lumpur Malaysia France Institute Diploma in Automotive Maintenance

Transmission 1 Synchronizer operation University Kuala Lumpur Malaysia France Institute Diploma in Automotive Maintenance

Transmission 1 Transmission power flow University Kuala Lumpur Malaysia France Institute Diploma in Automotive Maintenance

Transmission 1 Transmission power flow – neutral University Kuala Lumpur Malaysia France Institute Diploma in Automotive Maintenance

Transmission 1 Transmission power flow – neutral • As the clutch engage and engine running, input shaft and gear that integrated on it will rotate • Power than transmit to counter gear shaft and transmit to speed gear but power cannot be transfer due to no gear is locked to the output shaft University Kuala Lumpur Malaysia France Institute Diploma in Automotive Maintenance

Transmission 1 Transmission power flow – 1 st speed • As first gear is selected, synchronizer moves towards 1 st speed gear and lock it to main shaft. 1 st speed gear drives the main shaft and transfers power to the driveline • If typical 1 st speed gear ratio is 3: 1, and engine torque that entering is 298 Nm, the torque that exit is 894 Nm University Kuala Lumpur Malaysia France Institute Diploma in Automotive Maintenance

Transmission 1 Transmission power flow – 2 nd speed • As 2 nd gear is selected, synchronizer moves towards 2 nd speed gear and lock it to main shaft. 2 nd speed gear drives the main shaft and transfers power to the driveline • If typical 2 nd speed gear ratio is 2: 1, and engine torque that entering is 298 Nm, the torque that exit is 596 Nm University Kuala Lumpur Malaysia France Institute Diploma in Automotive Maintenance

Transmission 1 Transmission power flow – 3 rd speed • As 3 rd gear is selected, synchronizer moves towards 3 rd speed gear and lock it to main shaft. 3 rd speed gear drives the main shaft and transfers power to the driveline • If typical 3 rd speed gear ratio is 1. 5: 1, and engine torque that entering is 298 Nm, the torque that exit is 447 Nm University Kuala Lumpur Malaysia France Institute Diploma in Automotive Maintenance

Transmission 1 Transmission power flow – 4 th speed • As 4 th gear is selected, synchronizer moves towards 4 th speed gear and lock it to main shaft. 3 rd speed gear drives the main shaft and transfers power to the driveline • If typical 4 th speed gear ratio is 1: 1, and engine torque that entering is 298 Nm, the torque that exit is 298 Nm University Kuala Lumpur Malaysia France Institute Diploma in Automotive Maintenance

Transmission 1 Transmission power flow – reverse • When reverse gear is selected, shifting linkage moves the reverse idler gear to mesh with the reverse speed gear • Power flows from input shaft to countershaft and passes to reverse idler gear (change rotation direction) • Than passes to reverse speed gear and rotation will change again University Kuala Lumpur Malaysia France Institute Diploma in Automotive Maintenance

Transmission 1 Calculating Gear Ratio University Kuala Lumpur Malaysia France Institute Diploma in Automotive Maintenance

Transmission 1 Calculating Gear Ratio • The typical gear mesh has 45 teeth of driving and rotating at 200 rpm, while the driven gear has 75 teeth 1. calculate the gear ratio 2. calculate the output speed 3. calculate output torque if the input torque is 235 Nm University Kuala Lumpur Malaysia France Institute Diploma in Automotive Maintenance

Transmission 1 Transaxle – construction University Kuala Lumpur Malaysia France Institute Diploma in Automotive Maintenance

Transmission 1 Transaxle power flow – 1 st speed 1 - 2 Synchronizer unit 3 - 4 Synchronizer unit University Kuala Lumpur Malaysia France Institute Diploma in Automotive Maintenance

Transmission 1 Transaxle power flow – 2 nd speed 1 - 2 Synchronizer unit University Kuala Lumpur Malaysia France Institute Diploma in Automotive Maintenance

Transmission 1 Transaxle power flow – 3 rd speed 3 - 4 Synchronizer unit University Kuala Lumpur Malaysia France Institute Diploma in Automotive Maintenance

Transmission 1 Transaxle power flow – 4 th speed 3 - 4 Synchronizer unit University Kuala Lumpur Malaysia France Institute Diploma in Automotive Maintenance

Transmission 1 Transaxle power flow – 5 th speed Synchronizer unit University Kuala Lumpur Malaysia France Institute Diploma in Automotive Maintenance

Transmission 1 Transaxle power flow – Reverse idler gear University Kuala Lumpur Malaysia France Institute Diploma in Automotive Maintenance

Transmission 1 Transaxle power flow University Kuala Lumpur Malaysia France Institute Diploma in Automotive Maintenance