Sliding Gear Transmission Old school, used from late 1800’s to 1940’s? Has two or more shafts in...

Sliding Gear Transmission

•Old school, used from late 1800’s to 1940’s?•Has two or more shafts in parallel with sliding spur gears.

Sliding Gear Transmission

•If either gear is rotating, shifting is difficult and gear “clashing” will result.•Some manufacturers may still have a sliding gear for reverse.

Collar-shift Transmission

•Has two parallel shafts with gears in constant mesh•These “collars” slide on a hub that is splined to the output shaft, thus transferring power.•Gear “clashing” will occur if the gear speeds are not matched by double clutching.

• The shifter, rather than going straight to the next gear, makes a stop in neutral and then the clutch is released.

• This is to allow the engine to slow down (or with a tap on the gas, speed up when downshifting) so the transition into the next gear is much more smooth.

• The driver then depresses the clutch again and completes the shift into the target gear, and finally the clutch is released again, putting the car back into gear.

•Gears are in constant mesh and are collar shifted

•All forward gears are of a helical design

•Collars are equipped with synchronizers•Synchronizers eliminate the need to

equalize gear speeds before engagement•Used on all current models of cars – may

use a spur gear for reverse

Synchromesh Transmissions•Engine torque is applied to the input shaft (clutch shaft) when the clutch is engaged.

•The input shaft is fitted with a gear (input gear or clutch gear)

•The output shaft (main shaft) is inserted into, but rotates independently of the input shaft.

Synchromesh Transmissions

The different speed gears (1st, 2nd, 3rd 4th, etc.) rotate on the main shaft.

Synchromesh Transmissions•Parallel to (below or beside) the input and output main shaft is the counter shaft

•The counter shaft is fitted with different sized gears.

Synchromesh Transmissions

•One gear is in constant mesh with the input shaft gear.

•All of these gears are in constant mesh with the gears on the output shaft except …

Synchromesh Transmissions•Gear changes occur when the selected gear is connected to the output shaft.

•This is accomplished by locking a collar onto the selected gear.

•The collars are moved by shift forks.

Synchromesh Transmission

Switch to ppt #2

Transmission Components

Input Shaft

Main (Output) Shaft

Counter Shaft

Synchronizer Assembly

Synchronizer Operation

Synchronizer Operation

•First, the sleeve is moved toward the gear by the shift lever and engages the hub assembly•Second, the movement of the sleeve causes the inserts to press the blocking ring onto the cone of the gear

Synchronizer Operation•Third, when the components reach the same speed, the synchronizer sleeve slides over external dog teeth on the blocking ring and over the dog teeth of the speed gear’s shoulder. This action locks the gear to the main shaft.

Fork and Rail Assembly

Reverse Idler Gear

Transmission Operation

Power flow in neutral•The input shaft drives the counter shaft•All of the gears on main shaft rotate•The synchronizers are not engaged with any gear•No power is transferred to the output shaft

Power flow in first gear

•The power enters the transmission through the input shaft•The first/second synchronizer sleeve is engaged with the first gear dog teeth•The power is transferred from the input shaft, through the countershaft, and up to the first gear•The first gear drives the output shaft

Power flow in second gear•The power enters the transmission through the input shaft•The first/second synchronizer sleeve is engaged with the second gear dog teeth•The power is transferred from the input shaft, through the countershaft, and up to the second gear•The second gear drives the output shaft

Power flow in third gear•The power enters the transmission through the input shaft•The third/fourth synchronizer sleeve is engaged with the third gear dog teeth•The power is transferred from the input shaft, through the countershaft, and up to the third gear•The third gear drives the output shaft

Power flow in fourth gear

•The power enters the transmission through the input shaft•The third/fourth synchronizer sleeve is engaged with the fourth gear dog teeth•The power is transferred from the input shaft to the fourth gear•The fourth gear drives the output shaft

Power flow in fifth gear•The power enters the transmission through the input shaft•The fifth gear synchronizer sleeve is engaged with the fifth gear dog teeth•The power is transferred from the input shaft, through the countershaft, and up to the fifth gear•The fifth gear drives the output shaft in overdrive

Power flow in reverse gear

Reverse is often achieved by adding a third gear

-causing the output shaft to spin in the opposite (same) direction

Power flow in reverse gear•The power enters the transmission through the input shaft•The reverse gear synchronizer sleeve is engaged with the reverse gear dog teeth•The power is transferred from the input shaft, through the countershaft, through the reverse idler gear, and up to the reverse gear•The reverse gear drives the output shaft in reverse

GEAR RATIO FINAL

•1st 2.66:1 9.10:1

•2nd 1.78:1 6.10:1

•3rd 1.30:1 4.45:1

•4th 1.00:1 3.42:1

•5th 0.74:1 2.53:1

Transaxle

A manual trans-axle is almost identical to a manual transmission except:

1. The differential is built into the housing

2. The input shaft incorporates gears 1,2,3 @4

2. The counter-shaft is now the output shaft

3. The gears are generally smaller and pressed fit to facilitate a smaller area.

Transaxle

Transaxle

Input and output shafts

Transaxle

First Gear

TransaxleFourth Gear

Transaxle

Reverse

Transaxle Final Drive

Shifter Rails

Interlock System

Fork and Rail Assembly (internal)

Fluids

… are used to

_ ?

_ ?

…check the manufacturers specifications!