I don't know if you have found that after entering the era of electric vehicles, there are many more people who go to the sea to build cars. And the focus of the ppt conference is no longer to publicize how bullish their motors, batteries, and chassis are.
Because the structure of electric vehicle parts is much simpler than that of fuel vehicles, the technical threshold for research and development and production has been greatly reduced, and a large number of parts manufacturers have entered this market, and many car companies feel that these parts are cheaper than buying.
Batteries can be bought in the BYD and Ningde eras, motors can be bought by Huawei and Nidec, and even the chassis assembly of the car has begun to provide complete solutions from manufacturers.
Across the ocean, RIVIAN, a new car-making force, recently released their modular chassis assembly, and in China, Yo-Yo also released their skateboard chassis solution - super chassis.
But I thought about it for a while, what is the difference between the skateboard chassis and the toy 4WD and girder chassis?
In the past, the automobile industry was limited by the backwardness of the body manufacturing process, and the structure of the girder chassis + shell was widely used in the automobile, but with the improvement of the body design and manufacturing process, the bearing body began to be popularized, and the girder chassis was currently only seen in off-road vehicles and commercial vehicles.
This is because the girder chassis as a very long length of the flat structure, its biggest feature is soft, off-road can be deformed to make the four corners of the wheel ground as much as possible, normal driving to return to normal state. The body of the chassis is connected by a rubber bushing, and the shape of the body is not affected when the chassis is deformed.
Of course, when the softer girder chassis is input in the steering action, the girder chassis will first deform and then let the vehicle turn, which will lead to poor innate maneuverability of the girder chassis and drive like a boat.
In contrast, the load-bearing body is a frame structure, the rigidity is much higher than the girder chassis, and the subframe used to link the suspension and the body is much smaller than the girder chassis, the amount of deformation is smaller when steering, and the handling response speed is better than the girder chassis.
The above two pictures are lexus LX using a girder chassis, and the following picture is the NX of the load-bearing body, and it can be seen that the structure of the girder chassis and the load-bearing body is still very different.
Due to advances in body manufacturing processes, load-bearing bodies are widely used in today's automotive industry. Not only does it make the body structure simpler, but the body performance is also better.
Whether it is for girder chassis or load-bearing body, the addition of battery compartments will increase stiffness, but this is only because the battery compartment needs to meet the additional effects of safety protection requirements.
The battery is flammable and explosive, and it will become a huge safety threat if it is slightly damaged when it is collided. Therefore, it is very important to create a safe protective shell for the battery compartment. In addition, the battery compartment itself is very heavy, and structural parts such as beams and side beams located in the battery compartment also need to be strengthened.
Therefore, when designing the electric vehicle body and chassis, car companies will arrange multiple stiffeners in the battery compartment position, and strengthen the side beams, so that the battery is protected from external impacts, and the fuel vehicle does not need to protect the battery, and the number of under-the-car reinforcements is obviously much less than that of pure electric vehicles.
In addition, for oil-to-electric models, because the body-in-white body can contribute to the increase in body stiffness is not much, the battery compartment itself needs to have a sufficiently large stiffness. Like the BMW iX3 battery compartment using a complex steel and aluminum hybrid structure, the torsional stiffness of the battery compartment assembly itself reaches 25200Nm/°, and the torsional stiffness of the vehicle body is as high as 52500Nm/°.
What is this concept? The porsche 718 Cayman, which has the highest torsional stiffness without using carbon fiber, has a torsional stiffness of only 41,500 Nm/°.
In the load-bearing body, in order to strengthen the body strength near the battery compartment, the strength of the side beams needs to be improved. But on the girder chassis, the two girders that run across the bottom of the car become the best protective barrier for the battery compartment.
Unlike the load-bearing body that needs to add multiple protective beams to the battery compartment, the structure of the girder chassis does not need to be changed too much, and only a slight upgrade of the material can provide good protection for the battery compartment. At the same time, the stiffness of the girder itself has also been greatly improved due to the presence of high-strength battery compartments.
The non-load-bearing structure designed separately from the body and chassis is also conducive to installing different forms of body on the same chassis, which is a reason for the four-wheel drive car that everyone played with when they were children.
Therefore, RIVIAN, which specializes in off-road vehicles and pickup trucks, likes the skateboard chassis the most, and the structure of the girder chassis itself is very suitable for SUVs, pickup trucks, high chassis, high load carrying capacity models, coupled with the improvement of the battery compartment on the chassis stiffness, which perfectly solves the problem of low stiffness of the girder chassis.
Yo-Yo is also interested in the characteristics of high rigidity and good flexibility of the electric girder chassis, and has launched a skateboard chassis solution based on the girder chassis, a chassis can be matched with a variety of body, no longer limited to high chassis models.
After the electrification of the car, the threshold for building a car was suddenly lowered. If the chassis can provide mass production, the difficulty and cost of building a car will be greatly reduced. According to the official statement of Yo-Pao Technology, their skateboard chassis can shorten the vehicle research and development cycle by 6-12 months.
The new forces like this the most. The hardware of the vehicle does not need to worry about them, only need to develop the software part that they are best at.
Skateboard chassis like RICIAN are specially built for electric buggies and pickups, and do not require much modification to the girder chassis structure. But if you eat all models with a skateboard chassis like Yo-Yo- Yarrow, it is still quite difficult, especially low-chassis models such as cars, sports cars, and MPVs.
Because the skateboard chassis must have sufficient stiffness to ensure that there is enough thickness. The girder chassis has become thicker, and there is no way to reduce the height of the interior floor. This is a fatal drawback for both cars and sports cars that focus on low sitting, as well as MPV that focus on interior space and space.
Pure electric coupes with ultra-low chassis like the Audi e-tron GT usually need to dig a hole in the battery compartment to ensure rear space, while MPV like the Lantu Dreamer usually designs the battery to be as long and wide as possible, while reducing the thickness of the battery compartment.
Judging from the physical display, the yo-running super chassis is still very thick, and the floor height is expected to be comparable to the MPV floor height of Xena and Jiahua, which are relatively high, and the ground clearance is relatively small.
The thickness of the chassis encroaches on most of the ride space, so the suspension system needs to be designed as delicately as possible. The Yo-Running Super Chassis uses a front and rear double wishbone + vane spring structure. To make room for the crew compartment, the wishbones are designed to be short and the suspension travel is very short. From this point of view, the shock filtering ability of the yo-running super chassis is about to hit a big question mark.
Will skateboard chassis become a trend? I think it should be discussed on a case-by-case basis.
For rivian, which only makes high-chassis models such as pickup trucks and SUVs, the skateboard chassis has a natural advantage, not only is it stronger and stiffer than the traditional girder chassis, but also does not need to make too many changes to the structure of the girder chassis.
But to apply the skateboard chassis to other models, I think it is still not so practical. Because of the requirements of different models for the chassis, the difference is still quite large.
If you want to take care of all models with one chassis, you need to constantly compromise, and the result can only be nothing. Unless you put the passengers in the car about equal to the cargo, don't think about their ride. What kind of car can I buy in this way, I directly asked the goods to pull and carry myself?
Of course, the bosses of the new car-making forces do not think so, can attract investment, can use cool interactive technology to attract customers to sell the car is the most important. As for the customer after buying and found that the filter shock hard Bangbang regrets wanting to sell? The retention rate + rights of electric vehicles are limited to the first car owner, do customers dare to sell?