Automobile transmission shaft structure

time：2020-01-09 14:51:57| Publisher： 佚名 | see: |

Friends who know about cars all know that the car engine is an important heart of the car. Moreover, the power output from the engine does not directly act on the wheels to drive the car, but needs to pass through a series of power transmission mechanisms. What is the structure of automobile transmission shaft? How does the power get to the wheels? Let's take a look at how the transmission works.



Automobile transmission structure



Automobile transmission shaft structure: how is power transmitted?



The power output of the engine is to pass through a series of power transmission devices before reaching the driving wheel. The power transmission mechanism between engine and driving wheel is called automobile transmission system, which is mainly composed of clutch, transmission, transmission shaft, main reducer, differential and half shaft.



The power output from the engine first passes through the clutch, changes torque and speed from the transmission, then transmits the power to the main reducer through the transmission shaft, and finally transmits the power to the driving wheel through the differential and half shaft.



The layout of automobile transmission system is related to the position and driving mode of the engine. Generally, it can be divided into four types: front front drive, front rear drive, rear rear drive and center rear drive.



Automobile transmission shaft structure: what is the front drive?



Front wheel drive (FF) refers to that the engine is placed in the front of the car and the front wheel is used as the driving wheel. Now most cars adopt this arrangement. As the engine is arranged in the front of the car, the center of gravity of the whole vehicle is focused on the front section of the body, which is a bit "heavy at the head and light at the tail". But because the car is pulled by the front wheel, the front drive car has a very good straight-line driving stability.



In addition, because the engine power directly drives the front wheel with the half shaft after passing through the differential, it does not need to pass through the transmission shaft, so it is suitable for small cars. However, because the front wheel is responsible for driving and steering at the same time, the steering radius is relatively large, and the phenomenon of understeer is easy to occur.



Flow chart of automobile power transmission



Automobile transmission shaft structure: what is front and rear drive?



Front rear drive (FR) means that the engine is placed in the front of the vehicle and the rear wheel is used as the driving wheel. The front and rear weight of the fr vehicle is relatively balanced, with good handling performance and driving stability. However, there are many transmission parts and high quality transmission system. The transmission shaft running through the cabin occupies the platform space in the cabin.



Fr car has better handling, stability and braking performance, and now high-performance vehicles still like to use this layout.



Automobile transmission shaft structure: what is rear drive?



Rear drive (RR) means that the engine is placed at the rear of the rear axle and the rear wheel is used as the driving wheel. Because most of the weight of the whole car is concentrated in the rear, and it is driven by the rear wheel, so the starting and accelerating performance are very good, so the super sports car generally adopts RR mode.



The turning performance of RR car is more sensitive than FF and FR, but when the grip of rear wheel reaches the limit, there will be skid and tail flick phenomenon, which is not easy to control.



Automobile transmission shaft structure: what is the center rear drive?



Mid rear drive (MR) refers to placing the engine between the cab and the rear axle, and using the rear wheel as the driving wheel. This design of MR has been the mainstream driving mode of advanced sports cars. Because the engine with the largest inertia is placed in the center of the vehicle body, the weight distribution of the whole vehicle is close to the ideal balance, which ensures the best motion performance of Mr vehicle.



Mr car has two seats because of the middle engine and narrow compartment. Moreover, the engine is close to the driver and the noise is relatively high. Of course, people who pursue driving performance don't care.



Structural drawing of front drive vehicle



Automobile transmission shaft structure: the role of clutch



The clutch is located in the flywheel housing between the engine and the transmission, which is fixed on the rear plane of the flywheel, and the other end is connected with the input shaft of the transmission. The clutch is equivalent to a power switch, which can transmit or cut off the power input from the engine to the transmission. The main purpose is to make the car start smoothly, timely interrupt the power of the transmission system to match the shift, and can also prevent the transmission system from overload.



The clutch is mainly composed of driving part (flywheel, clutch cover, etc.), driven part (friction plate), pressing mechanism (diaphragm spring) and operating mechanism. There are friction clutch, hydraulic coupling, electromagnetic clutch and so on. At present, most of the clutches matched with manual transmission are dry friction clutch. The working principle of friction clutch is described below.



The clutch cover is fixed on the rear end face of the flywheel by screws. The friction plate in the clutch is pressed on the flywheel surface by the pressure plate under the force of the spring, and the friction plate is connected with the input shaft of the gearbox. The torque from the engine is transmitted to the gearbox through the friction between the flywheel and the contact surface of the pressure plate and the driven plate.



Before stepping on the clutch pedal, the friction plate is pressed tightly on the flywheel end face, and the engine power can be transmitted to the gearbox. When the clutch pedal is depressed, the force is transmitted to the release fork and release bearing through the operating mechanism. The release bearing moves forward to compress the diaphragm spring toward the flywheel end. The diaphragm spring moves in the opposite direction with the support ring as the fulcrum, and the pressure plate leaves the friction plate. At this time, the engine power transmission is interrupted. When the clutch pedal is released, the diaphragm spring returns to its original position, and the clutch is reconnected, Engine power continues to pass.



Structure of rear drive vehicle



Universal joint is the use of ball and other devices to achieve different directions of shaft power output, located at the end of the transmission shaft, to connect the drive shaft and drive