Automobile transmission, brake parameters detailed analysis

Through the introduction of the previous several articles, I believe you have a detailed understanding of the body parameters and engine parameters of the car, this article is mainly to explain the relevant parameters of the gearbox and brake. The transmission is composed of a variable speed transmission mechanism and a control mechanism, which is used to transmit the output power of the engine, and can change the combination of gears to meet different needs. ★ Function :1. Change the transmission ratio, expand the range of torque and speed of the drive wheel to adapt to frequently changing driving conditions, while making the engine work under favorable conditions (higher power and lower fuel consumption). 2. In the case that the direction of engine rotation is unchanged, the car can run backwards. 3. Use neutral to interrupt power transmission, so that the engine can start and idle, and facilitate transmission shift or power output. The number of gears we often say that the gearbox has several gears refers to the number of gears, gear refers to the engine at a certain speed, used to adjust the gear ratio of the gearbox, so as to achieve a reasonable torque. The more the number of gears, the finer the regional division of the engine output power, so that the engine can work in a smaller speed range, at any time to ensure the best working state, not only can obtain better power output, but also to ensure better fuel economy, the disadvantage is that the more the number of gears, the more complex the structure, the manufacturing cost is relatively high. Today, the number of gears in the gearbox is basically 4-8. Most manual gearboxes are 5 or 6, of which 5 is more, such as: Jetta, Civic, etc.; There are fewer 6 files, such as Corolla, Pentium, 1.6T Regal and so on. Most automatic transmissions are 4-6, and the more advanced ones have 7 and 8 gears. Four of the common models were: Versa, Yuedong, Focus, etc.; The common models of 5 gear are: Civic, Accord, Rui Yi, etc.; 6 common models are: Lavida, Regal, Magton, etc.; The common models of 7 gear are: many models of Mercedes-Benz, golf 6 generation, etc., 8 gear models are very few, only Lexus LS460h, BMW 5 series GT these two models. ● Transmission type According to different principles, the transmission is mainly divided into: manual transmission, automatic transmission, manual self-integrated transmission, variable speed transmission and dual clutch transmission. ◆ Manual transmission Manual transmission is to manually select the gear position, change the gear mesh position in the gearbox, change the transmission ratio, so as to achieve the purpose of speed change. Manual transmission needs the shift lever and the clutch to operate together to complete, first need to step on the clutch, so that the gear separation, and then change the gear, and then release the clutch, so that the gear combination. Manual transmission is a relatively original transmission, his advantage is that the cost is low, the driver can control the vehicle gear as he likes, choose the right gear, control the vehicle speed. The disadvantage is that it has a certain degree of driving difficulty and the operation is relatively complex. Automatic transmission Automatic transmission is composed of hydraulic torque converter, planetary gear and hydraulic control system, through the way of hydraulic transmission and gear combination to achieve the role of transmission. The automatic transmission can automatically change gears according to the depth of the accelerator pedal and the speed change. The advantage is that the operation is simple, the disadvantage is that the power transmission is delayed, the response is slow, and the manufacturing cost is high. Manual self-integrated transmission Manual self-integrated transmission is actually an automatic transmission, but with the function of manual control. Its advantage is that the driver can artificially force the gearbox to shift up or down, making it easier to overtake or save fuel. ◆ Transmission continuously variable transmission belt and working diameter of the main and slave wheel to transfer power, can achieve continuous change of transmission ratio, so as to get the best match between the transmission system and the engine working condition. It is simpler and smaller than the traditional automatic transmission. In addition, it can freely change the transmission ratio, so as to achieve the whole stepless transmission, so that the speed of the car changes smoothly, without the "ton" feeling when the traditional gearbox shifts. The disadvantage of stepless transmission is that it cannot match the engine with larger torque, so it is generally used in some small and medium-sized cars. ◆ Dual-clutch transmission: dual-clutch transmission should be said to be the best transmission solution now, it is based on manual transmission rather than automatic transmission, in addition to the flexibility of manual transmission and the comfort of automatic transmission, but also to provide uninterrupted power output. ● The transmission needs to use the shift lever to control the gear, and now the shift lever type in the car mainly has the following ways: ◆ The longest shift lever seen in the row, 80% of the models use this way. The current shift lever of the shift lever is used for more advanced models, basically for electronic control shift system, such as Mercedes-Benz S-class, E-class and so on. ◆ There are not many models used in the center control table, generally only a few MPV will be used, such as: Changhe Suzuki Langdi. The general dial type is used in conjunction with the upper three transmission types, that is, the vehicle can either shift with a shift rod or shift with the dial on the steering wheel. ● Front/rear brake type The brake is the brake, which is the part that stops or slows down the moving car, commonly known as the brake and brake. The brake is mainly composed of brake frame, brake parts and control device, some brakes are also equipped with brake parts of the automatic adjustment device brake is mainly divided into drum and disc, and disc is divided into several types, the following is a brief introduction: ◆ drum drum brake is also called block brake, is by brake block on the brake wheel to achieve braking. Now the mainstream of the drum brake is the internal tensioning type, its brake block (brake shoe) is located inside the brake wheel, and the brake block opens outward when braking, rubbing the inside of the brake wheel to achieve the purpose of braking. Drum brakes are easy to produce thermal attenuation, so they are generally only used in small and micro cars, and only on the rear wheels. ◆ Solid disc disc brake is also known as disc brake, as the name suggests is named for its shape. It is controlled by hydraulic pressure, the main parts are brake disc, pump, brake caliper, oil and so on. The brake disc is made of alloy steel and fixed to the wheel and turns with the wheel. The pump is fixed on the bottom plate of the brake, and the two friction sheets on the brake clamp are respectively installed on both sides of the brake disc. The piston of the pump is driven by the hydraulic action of the oil transport, which pushes the friction sheet to the brake disc and causes friction braking. The action is like using pliers to clamp the rotating plate and force it to stop. The disc brake has the advantages of fast heat dissipation, light weight, simple structure and convenient adjustment. In particular, the high temperature resistance is good when the load is high, the braking effect is stable, and is not afraid of mud and water. In winter and bad road conditions, the disc brake is easier to stop the car in a short time than the drum brake. Solid disc is the brake disc is made of a round solid metal, so it is called solid disc. ◆ Ventilated disc Because in the braking process, the friction between the caliper and the brake disc will produce a lot of heat, so that the brake disc quickly heats up and reduces the braking effect. So the ventilation disc was born: the centrifugal force generated by the vehicle in the exercise can make the air convection, to achieve the purpose of heat dissipation, which is determined by the special structure of the disc. From the appearance, it has many holes leading to the center of the circle on the circumference, these holes are made by a special process, so the heat dissipation effect is much better than the ordinary disk, but the cost is also more expensive, generally medium and high-end cars will be used. The perforated ventilation disc is to punch holes on the surface of the disc on the basis of the ventilation disc to ensure the maximum extent of air circulation and reduce thermal attenuation. Generally on high-power sports cars will only use the perforated ventilation disc. ◆ Ceramic carbon fiber type Ceramic carbon fiber type is to add extremely heat-resistant ceramic materials on the brake disc on the basis of the punched ventilation disc. This can improve the high temperature resistance of the brake disc, can effectively reduce thermal attenuation, and also has the characteristics of lightweight. This brake disc is generally only used in racing cars or supercars, such as the Ferrari F430 with this brake disc. ● Handbrake types There are mainly the following types of handbrakes: hand-pulled, pedal, electronic. The hand pull type is the most common type of hand brake, and most models use this way. The hand pull handbrake is located in the middle of the front seat, like pulling up to lock. ◆ Pedal type Pedal type handbrake is generally on the left side of the vehicle, divided into two ways: one is to tighten and loosen the foot, the other is to tighten with the foot, loosen with the hand. Many American cars use foot brakes. The electronic handbrake is also the electronic parking brake system. The electronic parking brake system is a technology that integrates the temporary braking function and the long-term braking function after parking, and realizes the parking braking by electronic control mode. It is a technology that realizes parking braking by electronic control mode. Its working principle is the same as that of the mechanical handbrake, which is achieved by the friction generated by the brake disc and the brake pad to control the parking brake, but the control mode has changed from the previous mechanical handbrake pull rod to an electronic button. Now many high-end cars are beginning to use electronic handbrakes. v Front/Rear hub specifications The hub is the tire rim, which is the part of the wheel with round holes that can be inserted into the drive shaft. Whether the shape of the wheel is beautiful, many times can play the role of the finishing touch. The hub has a certain specification, for example, 6.5J×16 means: the width of the hub is 6.5 inches, J indicates the outline of the rim, and the diameter of the hub is 16 inches. ● Front/rear tire specifications Tire specifications are generally expressed in this way: 175/65R15, 175 indicates that the tire width is 175 mm; 65 indicates the flat ratio, that is, the height of the tire section is 65% of the width; R "refers to the structure of the tire, indicating that the tire is a meridian structure; 15 indicates that the diameter of the hub is 15 inches. Some high-speed tires will also add a letter behind, for example: 245/45R18H, this H means that the tire can withstand the maximum speed of 210km/h, the letter represents the speed as follows (km/h) : M: 130; N: 140; P: 150; Q: 160; R: 170; S: 180; T: 190; U: 200; H: 210; V: 240; W: 270; Y: 300; Most cars have the same front and rear tire specifications, but some high-power luxury cars and sports cars have wider rear tires than the front tires, because the rear tires need to withstand more power and need good grip. In general, the flat ratio determines the use of the tire: the car with a higher flat value is more comfortable, and the car with a lower flat value is more athletic. The general car will have a spare tire, of which the full size spare tire is the same specification as the standard equipped tire; The small spare tire is smaller than the standard tire specifications, and the maximum speed is generally only 80km/h; A no-spare tire is a car that does not have a spare tire or has explosion-proof tires that are not equipped. --------------------------------------------------------------------------------