What about the so-called chassis adjustment?
Everyone knows that there are “three big pieces” in cars: engines, transmissions, and chassis. These three components have the highest technological content and are the most core components on the car. At the same time, their prices are also the highest, accounting for more than 60% of the total car price. Their technological advancement, reliability of use, and the ability of manufacturers to make adjustments directly determine the performance of automobiles.
We are all familiar with engines and transmissions. You can see them when you open the engine compartment. They are usually combined together and collectively referred to as the powertrain of a car. However, many people don’t know what the chassis is. Some people say that the car ’s suspension is the chassis, and some people say that the bottom iron plate of the car is the car chassis, and some people say that the car ’s chassis, except the engine gearbox, belong to the chassis. Who is right? Let ’s take a closer look at what a car ’s chassis is, and what ’s so-called chassis tuning.
First of all, let us be clear. The so-called “car chassis” does not refer to a single component or assembly, but refers to a larger system on the car. It is composed of the drive system, the driving system, the steering system, and the brake system. It is a combination of powertrain systems, with support, installation of automobile engines and other various component assemblies, bearing transmission of engine power, supporting the weight of the entire vehicle, and realizing walking, controlling the direction and speed of the car, and manipulating and controlling the attitude and state of the vehicle body. And other functions to ensure normal and safe driving of the car. The chassis of the car is the foundation of the car, and the overall shape of the car is also determined by the type of the chassis.
The body structure of a car can be divided into two types: a loaded body and a non-loaded body, and their chassis structures are also different. Early cars and today’s trucks all used non-load-bearing body structures. There was a huge and strong frame. Almost all parts of the car were mounted on the frame. It is the basis of the car chassis. The so-called Chassis refers to all parts of the car except the engine and body; today’s cars and SUVs basically use a non-load bearing body structure, and all parts of the car are directly or indirectly mounted on the body. The chassis refers more to the suspension system, steering system and braking system.
Let’s take a look at the specific parts of the chassis.
1. Transmission system: The transmission system is mainly composed of clutch (or torque converter), transmission (manual, automatic), universal transmission and drive axle. It can also be said that from the clutch (or torque converter) When it comes to driving wheels, all the components in the middle belong to the drive system. Its main function is to reduce torque, increase torque, change torque, achieve reverse, interrupt power transmission of the transmission system, and other functions such as wheel differential.
For rear-wheel-drive cars, they are arranged in this order; for front-wheel-drive cars, the transmission and drive axle are combined into one, collectively referred to as the gearbox, and the engine is usually And the transmission are collectively called the powertrain of the car. A paradox is formed here: the three major parts of the car are the engine, gearbox and chassis, but the gearbox is included in the transmission system and is part of the chassis. According to this classification, there should be only two major cars on the car. Parts: engine and chassis. So now everyone talks about the structure of the car. Generally speaking, the car is composed of the four parts of the engine, chassis, body and electrical and electronic equipment. The three major claims are actually based on the truck, which is a bit outdated.
2. Driving system: The driving system of the car is composed of frame, axle, suspension, wheels and tires. Its role is to receive the engine torque from the transmission system and generate driving force to drive the car; to bear the total weight of the car, to transmit and bear the reaction forces and torque from the road in all directions on the wheels; The shock and vibration of various forces and moments of the car, and buffer it to ensure the smoothness and handling stability of the car; work in coordination with the steering system to control the direction of the car; work in coordination with the braking system To ensure the safety and stability of the car.
For the non-load-carrying body, it has a huge and strong frame, and the various forces encountered by the car in the end will be carried by the frame. The suspension system can use very tough leaf springs, which is very comfortable. Poor but can bear a lot of weight, or use a very rigid independent suspension; for cars and SUVs with a load-bearing body, it has no frame, and all parts of the driving system are ultimately installed on the body In the end, the various forces that the car is subjected to are ultimately taken up by the body. Most of the suspension systems use a more comfortable independent suspension. In order to enhance the stiffness of the chassis system, the suspension system and the body usually use a sub-frame to Join.
The car’s driving texture, or handling, is mainly determined by the car’s driving system, and the suspension system plays a vital role in it. Most of the cars use independent suspension, the structure types are Macpherson type, double-wishbone type, multi-link type, etc., supplemented by different buffer springs and shock absorbers, the car’s handling will be completely different. Especially the support and deformation of the suspension system when the car turns, it has a great impact on the handling of the car. Therefore, it is reasonable to look at the suspension of the car’s chassis.
3. Steering system: The special mechanism used to change the direction of the car on the car is collectively called the car steering system, which is mainly composed of the steering control mechanism (steering wheel, steering column, etc.), steering gear, and steering transmission mechanism (transverse, smooth Tie rods, steering ball heads, etc.), steering power steering mechanism (steering pump, steering motor) and so on. The function of the car steering system is to ensure that the car can drive straight or steer according to the driver’s wishes. It cooperates and coordinates with the car’s suspension system, which directly affects the maneuverability of the car.
At present, most steering systems of automobiles have power-assisting devices. Generally, there are two types of hydraulic assistance and electric assistance. Electric passenger power steering systems are mostly used in passenger cars. It has the characteristics of steering with speed, which can make the car better maneuverable, but its disadvantage is that the power is less; and trucks and off-road vehicles mostly use hydraulic power assistance. The steering system has greater assistance and more stable and reliable performance. The disadvantage is that it increases the engine load and cannot change the amount of assistance with the speed of the vehicle.
4. Braking system: The automobile braking system refers to a series of specialized devices that can generate braking force on the automobile. It is mainly composed of brake pedal, brake master cylinder, brake cylinder, brake pipeline, wheel brake, etc. . Its main function is: slow down the car or park the car within the shortest distance according to the needs to ensure driving safety, and make the driver dare to exert the high-speed driving ability of the car, thereby improving the productivity of car transportation; and can make the car park reliably On the ramp.
The braking system is without a doubt the most important active safety device in a car. It can be roughly divided into two types of the hydraulic braking systems and pneumatic braking system. In light vehicles and passenger cars, more hydraulic braking systems are used. In order to enhance the braking effect or to maintain the stability of the vehicle body during braking, various brake assist systems such as ABS and ESP have been developed on automobiles. , EBD, ASR, TCS, HAC, AUTOHOLD, HDC, BOS, etc., they are indispensable for maintaining the driving safety of the car.
Therefore, the chassis of a car is a general term for a series of parts that support the car and control the state of the car. In our most common cars, all components except the engine, body, and electrical systems can be classified as chassis. In this regard, the most misunderstood thing is that the large iron plate at the bottom of the car is used as the chassis of the car. In fact, it is a part of the car body, not the chassis. What we usually refer to as scraping the chassis and rusting the chassis refers to this floor.
Generally, the chassis structure of different models is also different. Some models so-called adopt the same chassis as certain models, in fact, they use the same transmission, suspension, steering and braking systems as some models; some models are Developed on the basis of these chassis, based on the original chassis, some changes have been made, such as raising the chassis suspension of the car, and it can be developed into an SUV model.
However, everyone will still have a feeling that even if different models with the same chassis, their driving experience is different, such as the hardness of the suspension, the feel and accuracy of the steering system, the height of the brake pedal, the clutch pedal High and low, roll when the car is cornering … etc, why on earth? This involves a crucial technical process in the design and manufacturing of automobiles: chassis adjustment.
The so-called chassis adjustment usually refers to the setting of suspension systems such as suspension systems, steering systems, and braking systems. The ultimate goal is to make the various components of the automobile chassis relatively unified, so that it has a certain relevance and integrity. . Chassis adjustment is a very complicated system engineering. It is not just a repair-and-fix adjustment after car manufacturing molding, but it participates in the car design and manufacturing process throughout the process. It can be divided into early development, mid-development and development. The latter three stages. Adjust the parameters of each system according to the positioning of the model, the environment of use, and the habits of the target customer.
For example, today’s ordinary family cars are basically pursuing comfort. In this way, its suspension system must be adjusted softer, with better shock absorption, and the road feel is not very clear. The steering system is adjusted lighter. The safety is better, the steering characteristic is the main, and the brake system is slower to adjust. For performance cars, it seeks good handling, so the suspension system must be stiffer, and the steering system feels heavier and more stable. Precise, the braking system is more responsive, and so on. For some more advanced models, in order to achieve the unification of comfort and good handling, an active suspension system will be used to automatically adjust the softness and rigidity of the suspension system and the steering system according to the speed of the vehicle and the quality of the road. Feeling etc.
It can be said that chassis adjustment is the most important place to test the strength of the OEM. Even if the chassis is the same structure, different manufacturers will adjust different styles and driving characteristics, and different chassis adjustments will have different personalities. Car models. It requires rich experience and a large amount of raw data accumulation, as well as various feedback data during the use of the car, etc. Therefore, it is not a technology that can be formed in a short time, but a technology accumulation of dozens or even hundreds of years by car companies. Therefore, the chassis adjustment skills of some old car companies are very good, such as Citroen, the torsion beam suspension system used by it is even better than some multi-link suspension systems.
It should be said that the chassis of a car is a very technically complex system on the car, and its structure and tuning technology are even more complicated than the engine and gearbox. For the domestic independent brands at this stage, they may be able to make their own engines and develop their own transmissions, but no car company has yet to fully develop and adjust a chassis system, even if it can completely reverse a certain model. The chassis of the vehicle model is also far from the prototype due to the lack of later adjustment skills. Therefore, the current independent brands are more directly using the chassis system of some joint venture cars, and the road of independent research and development is long and heavy.