I don't understand the chassis design of pure electric vehicles, and I don't want to review the mini four-wheel drive quickly.

Today's topic begins with finding fault with everyone. I'll give you two seconds to distinguish the following two pictures.

In order to test what interesting answers non-automobile practitioners will have, I threw this question to my family, and my brother's first reaction was "driving before driving".

good ..

This answer exposes two problems.

First of all, he didn't understand that it was actually a mid-engine four-wheel drive. Don't believe it? I'll open it for you.

Of course, this is not the biggest stalk. Obviously, he hasn't grasped the core of the difference-this is simply the difference between a toy car and a real car.

Seriously, this car is actually the American technology and super sports car manufacturer Karma? A New Modular E-Flex Platform (Chassis) for Automobile Industry. As an electric platform based on skateboard chassis, an extended range version is also designed. Here, this is the picture below.

Note: The skateboard chassis structure can directly put the battery and power supply system on the chassis.

As for the toy car, it's time to sacrifice the stock in hand. If you like mini four-wheel drive, you know that this is the MA chassis launched by Tamiya 20 13-a four-wheel drive chassis suitable for both new and old players.

Note: The concept of "getting off" is opposite to "static car". The former is a car modified for racing performance, and the latter is a car modified for viewing.

This is a very interesting discovery. I'm not a friend of the automobile industry, but I don't know much about the changes of automobile chassis now. Especially the electric car, suddenly looks like a mini four-wheel drive, amazing!

As an autobot who grew up playing mini four-wheel drive, his sense of mission exploded instantly, so we must have a good talk today.

Enlightenment from chassis design of mini four-wheel drive vehicle

The mini four-wheel drive we are discussing today is the next one. Since it is for the competition, its chassis design can be summarized as follows.

1, lightweight

Lightweight structures, such as hollow structures; Lightweight materials, such as carbon fiber or engineering plastics.

Don't think that 32.9g is light. In fact, MA chassis is a relatively thick chassis, like chassis, which can be excavated in the following ways, more hollow structure and thinner.

Corresponding to cars, the chassis structure of pure electric vehicles also has similarities. For example, the material is made of aluminum alloy which is lighter than steel, or it can be designed as a hollow structure. Like Tesla model? The chassis structure of S is made of aluminum alloy.

Wait until the model? 3. Compared with the vehicle model, the chassis structure is further simplified.

2. Chassis strength

Because of the need to fly on the runway and ensure the good stability of the car in high-speed movement, the chassis of mini four-wheel drive needs to have enough strength. Therefore, there will be a leading phoenix tail in the later stage, such as the modification shown below, and the flying wing guard of the leading phoenix tail is very enjoyable.

Of course, the pure electric vehicle will not adopt such an exaggerated reinforced design, but compared with the traditional load-bearing body, it has undergone several obvious changes for the purpose of protecting the battery pack and high-voltage wiring harness.

The first place is the use of a solid battery shell. For example, Weilai ES8 will have anti-collision design on both sides of the battery pack shell.

The second is to dilute the concept of collapse energy absorption.

Although the general idea is to let the impact energy absorb a part in the passenger compartment and then transmit it downward as far as possible through the beam structure, the structure will change. Most obviously, in order to arrange a larger power battery on the floor, the floor beams and longitudinal beams will be reduced. For example, BYD's blade battery arrangement is to enlarge this design to the extreme.

Because the anti-collision ability in the middle is weakened, the classic method is to deepen the front longitudinal beam. The energy absorption performance of the front longitudinal beam will be improved obviously after the cross-section height increases downward. Like Tesla model? This is the case with the X's front longitudinal beam, which is almost invisible in fuel passenger cars.

Note: Of course, this scheme also has shortcomings, and it is necessary to open holes or gaps in the front longitudinal beam to avoid the motion envelope of the semi-axle.

In addition, the longitudinal beam is prone to local stress concentration after opening, so it must be strengthened around the opening.

Of course, it does not mean that a good design will not be retained, such as unloading the design. Weilai ES6 two-stage anti-collision beam can better guide the vehicle to slide out of the collision area. Passat's A-pillar crash in R&D test is related to the lack of this design.

Note: Electric vehicle chassis plays an important role in anti-collision. Compared with some oil-modified cars, its body-in-white has gradually lost the characteristics of the traditional load-bearing body (or its importance has decreased).

3. Modularization

Mini four-wheel drive is popular all over the world, and it is inseparable from the pursuit of generations of teenagers. Why is there such magic? In addition to the competitive charm and the blessing of the animation of Four Wheel Drive Brothers, the most important thing is that it is very difficult to get started. Even seven or eight-year-olds can assemble four-wheel drive in a short time.

Note: At that time, Tian Gongjun, the president of Tamiya Model, had a very clear requirement for the design of four-wheel drive-"making a model that can be completed in simpler steps".

Note: the motor is directly disassembled, and the fender is buckled to reduce wind resistance, which is very car-making.

The current thinking of automobile design coincides with it.

For example, the Volkswagen MEB platform. MEB adopts modular design, with fewer assembly processes and higher integration, and the body size can be shortened, expanded or modified in other ways.

Note: according to the size, it includes all kinds of models from SUV to hatchback.

The design complements each other, and in order to improve the energy absorption space of the front cabin, the components of the front cabin will be highly integrated, which indirectly promotes modularity.

Like a model? s？ The motor and inverter are integrated together, saving a lot of space in the front cabin. While ensuring the collision energy absorption space, the front cabin can also save a suitcase.

Why is the chassis of an electric car like a toy car? What is the future trend?

This paper introduces the mainstream design method of pure electric vehicle chassis structure, but why it is similar to mini four-wheel drive chassis is also a very curious place for everyone.

It can be explained from several aspects.

The working principle of electric vehicle is: battery → current → power regulator → motor → power transmission system → driving the car. The working principle of mini four-wheel drive is actually very similar (except there is no power regulator).

In addition, in order to obtain more battery layout space and lower center of gravity, pure electric vehicles also adopt the combination of battery and chassis, and use a huge and heavy alloy plate to install the battery, which coincides with the intention of mini four-wheel drive.

In contrast, the traditional automobile chassis consists of four parts: transmission system, driving system, steering system and braking system, and their working principles are very different. For pure electric vehicles, the clutch and transmission can be omitted, and the motors are arranged on the front and rear axles respectively, which is impossible in traditional vehicles.

Of course, this change is not achieved overnight, and the chassis of electric vehicles has experienced a period of development.

In 2002, Christopher, then vice president of research and development at General Motors? Dr. Borroni-Bird designed a design called AUTO? Nomy's skateboard chassis concept.

He integrated the electric vehicle chassis, power system, steering system, braking system and other on-board systems into a "skateboard" through electronic control. This "skateboard" is also connected with the software of the car body through the interface, which is a perfect modular design.

But before Tesla, the research and development ideas of traditional car companies were mainly carried out on the traditional car platform. After all, developing a brand-new pure electric platform has high risks and low returns. Therefore, for a long time, the battery pack was often placed under the back seat. The advantage is that it will not sacrifice the crash test results, and the disadvantage is that it will occupy the space in the back row and trunk.

The appearance of Tesla greatly promoted the application of skateboard chassis. Putting all the high-energy batteries under the passenger seat, or more than 7000 small batteries, caused great controversy at that time. Fortunately, their bodies and chassis are designed reasonably, and battery management is leading through their own BMS. And this has become the future trend.

Overview of aluminum channel

The energy of electric vehicles is transmitted through flexible wires, and the direct benefit is that the battery and power system are more freely arranged. With the continuous innovation of electrification technology, its chassis structure is also developing in the direction of modularization and intelligence.

Of course, it is not entirely correct to equate the pure electric vehicle chassis with the mini four-wheel drive. For example, mini four-wheel drive still has a transmission shaft to realize four-wheel drive, which has the characteristics of traditional car design, but the general direction of the two is similar.

The author also hopes to understand the frontier dynamics of the industry through this introduction. The increasingly popular "skateboard chassis" of pure electric vehicles is believed to be familiar to more people in the future.

This article comes from car home, the author of the car manufacturer, and does not represent car home's position.