Pic. 6.4. Schematic diagram of a five-speed manual transmission mod. iB5: 1 - rear cover of the gearbox housing; 2 - gearbox housing; 3 - breather; 4 - the working cylinder of the clutch release hydraulic drive; 5 - clutch housing; 6 - clutch release bearing; 7 - input shaft; 8 - secondary shaft; 9 - main gear and differential.
Pic. 6.5. Schematic diagram of a six-speed manual transmission mod. МТХ-75: 1 – reverse gear; 2 - gear V transmission; 3 - drive gear IV gear; 4 - clutch of inclusion of III and IV gears; 5 - gearbox housing; 6 – a leading gear wheel of III transfer; 7 – gear wheel of the II transfer; 8 - gear wheel of the 1st gear; 9 - clutch housing; 10 - input shaft; 11 - differential case; 12 - main gear drive gear; 13 - drive gear of the 1st gear; 14 – clutch of inclusion of I and II transfers; 15 – a leading gear wheel of the II transfer; 16 – gear wheel of III transfer; 17 - secondary shaft; 18 - gear IV gear; 19 - drive gear V transmission; 20 - clutch for engaging V gear and reverse gear; 21 - reverse drive gear.
Manual transmission mod. iB5 (pic. 6.4) or MTX-75 (pic. 6.5) made according to a two-shaft scheme with five synchronized forward gears. Manual transmission mod. MMT6 is made according to a three-shaft scheme with six synchronized forward gears.
Pic. 6.6. Schematic diagram of a six-speed manual transmission mod. MT-66: 1 - gear VI gear; 2 - secondary shaft of I and II gears; 3 - gear V transmission; 4 – a leading gear wheel of the II transfer; 5 – coupling of inclusion of transfer of a backing; 6 – a leading gear wheel of transfer of a backing; 7 – a secondary shaft of transfer of a backing; 8 – an output gear wheel of transfer of a backing; 9 – clutch of inclusion of I and II transfers; 10 - drive gear of the 1st gear; 11 - output gear of I and II gears; 12 – gear wheel of III transfer; 13 - input shaft; 14 - gear wheel of the 1st gear; 15 – a leading gear wheel of III transfer; 16 - secondary shaft III and IV gears; 17 - output gear III and IV gears; 18 - driven gear of the main pair; 19 - differential housing; 20 - clutch of inclusion of III and IV gears; 21 - drive gear IV gear; 22 – gear wheel of the II transfer; 23 - gear IV gear; 24 - drive gear V transmission; 25 - clutch of inclusion of IV and VI gears; 26 - the drive gear of the VI gear.
Manual transmission mod. MT-66 (pic. 6.6) made according to a four-shaft scheme with triple synchronization of I and II gears, with double synchronization of III gear and with single synchronization of IV, V and VI gears. The gearbox and final drive with differential share a common crankcase. The clutch housing is attached to the front of the gearbox housing. A stamped steel cover is installed on the rear of the gearbox housing.
The forward gears are switched on by axial movement of the synchronizer couplings mounted on the shafts. The gearshift mechanism is located inside the gearbox housing on its left side. Outside there are two levers of the mechanism - the gear selection lever and the shift lever.
The manual transmission control drive consists of a gear lever link with a ball bearing mounted on the base of the body, two shift and gear selection cables, as well as a mechanism installed in the gearbox housing. To ensure a clear shifting of gears, the shift lever of the shift mechanism is made in one piece with a massive counterweight.
The gear selection and shift cables are structurally different from each other and are not interchangeable.
The main gear is made in the form of a pair of cylindrical gears matched according to noise. Torque is transmitted from the driven gear of the final drive to the differential and then to the front wheel drives.
The differential is conical, two-satellite. The tightness of the connection of the internal hinges of the front wheel drives with the differential gears is ensured by oil seals.
The automatic transmission with adaptive control system provides the optimal shifting mode for almost any driving style and road conditions. Automatic transmissions installed with a 2.3-liter gasoline engine and a 2-liter diesel engine are identical in design and differ only in gear ratios.
A feature of automatic transmissions of Ford Mondeo cars compared to previous generations of automatic transmissions is the ability to switch from fully automatic control mode to manual mode (so-called sequential gearbox), in which the driver, during the acceleration of the car, independently chooses the moment of switching to overdrive. This allows, if desired, to achieve more intensive acceleration compared to automatic mode, artificially delaying the upshift, and bring the engine speed to the maximum torque range. At the same time, the electronic control system constantly monitors the vehicle speed and engine load, eliminates driver error by not allowing him to shift into a higher gear at low speed to avoid engine overload, or downshift at too high a speed, which eliminates the possibility of exceeding the maximum allowable engine speed. When the vehicle speed decreases, the gears automatically switch to lower gears without the participation of the driver. When the car comes to a complete stop, 1st gear is automatically engaged.
The automatic transmission consists of a torque converter, pump, planetary gear, multi-disc clutches, multi-disc brakes and a valve block.
Pic. 6.7. Torque converter: 1 - drive disk; 2 - torque converter housing; 3 - turbine; 4 - overrunning clutch; 5 - reactor; 6 - pump wheel.
torque converter (pic. 6.7) acts as a clutch and serves to smoothly connect the engine and gearbox mechanism, increase torque at the beginning of the car. The torque converter housing is connected to the engine crankshaft through the drive plate and rotates constantly when the engine is running.
The internal cavity of the torque converter is filled with a working fluid for automatic transmissions. The crankshaft of the engine rotates the torque converter and drives the pump wheel, which creates flows of working fluid in the direction of the turbine wheel. The turbine wheel begins to rotate due to the flow of the working fluid created by the pump wheel.
With a large difference in the rotational speeds of the turbine and pump wheels, the reactor changes the direction of the fluid flow, increasing the torque. As the frequency difference decreases, it is excluded from operation, as it is installed on a freewheel.
A pump located at the front of the gearbox housing pressurizes and supplies fluid to all systems in the gearbox.
Pic. 6.8. Planetary gearbox of the Ravigne system: 1 - long satellite; 2 - carrier; 3 - small sun gear; 4 - a large sun gear; 5 - short satellite; 6 - ring gear.
Ravigne planetary gear (pic. 6.8) is a gear train with external and internal meshing of gears, which provides various ways of connecting its elements to obtain various gear ratios.
Pic. 6.9. Scheme of operation of a multi-plate clutch: A - multi-plate clutch is on; B - multi-plate clutch is off; 1 - ball valve; 2 - sealing ring; 3 - piston; 4 - friction disc; 5 - friction disc with pads; 6 - thrust disk; 7 – coupling hub; 8 - spring stop; 9 - retaining ring; 10 - return spring.
Pic. 6.10. Scheme of operation of the disc brake: A - the brakes are on; B - brakes are off; 1 - thrust disk; 2 - friction brake discs with pads; 3 - friction disc; 4 - return spring; 5 - piston; 6 - gearbox housing; 7 – a cover of a case of a transmission.
Principles of operation of a multi-plate clutch (pic. 6.9) and disc brake (pic. 6.10) very similar. The difference lies in the fact that the multi-plate clutch connects the gearbox links to each other, and the disc brake connects to the gearbox crankcase. The working fluid supplied to the clutch actuates the piston, due to which the friction discs are compressed. The links blocked by the clutch begin to rotate in one piece.
When the disc brakes are released, the working fluid stops flowing into the clutch and the piston returns to its original position under the action of a return spring.
The design feature of the multi-plate clutch is that it is in constant rotation. Under the action of centrifugal force acting on the working fluid, pressure is created that prevents the clutch from unlocking. Additionally, a ball valve is installed in the coupling, located as close as possible to the edge from the center of the coupling. When the pressure of the working fluid in the chamber of the multi-plate clutch increases, the ball valve closes the drain hole, and when the pressure in the chamber decreases, the ball valve opens the drain hole under the action of centrifugal force and the clutch unlocks.
The automatic transmission control drive is cable-operated, designed on the same principle as the manual transmission control drive, but differs from it in the number and design of parts. The automatic transmission selector is installed in the same place in the floor tunnel as the manual transmission control lever and is connected to the control unit on the gearbox by a cable.
The differential of an automatic transmission is completely similar in design to the differential of a manual transmission.
To repair a transmission, especially an automatic transmission, a large set of special tools and appropriate training of the performer are required, therefore, this section discusses only the removal and installation of the transmission, the replacement of its seals, and the repair of the drive. If necessary, repair the gearbox at a specialized service.
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