Image: Tesla patent
Tesla has developed a unique for the automotive industry way to produce their cars. Model Y is produced using a single-piece casting, which not only improves vehicle safety, but also provides significant savings, which allows for rapid scaling of production. Tesla filed a patent for "Integrated energy absorbing castings" in which it describes the details of the invention.
The safety of vehicle occupants is directly dependent on the design of the vehicle and whether it is able to effectively protect them during impact. A good design has compress or crush zones that react in response to impact force and effectively absorb it. Tesla has developed a single-piece front and rear casting that gives energy-absorbing protection from such impacts.
Conventional crash energy absorption systems for vehicles include a variety of component parts. Such systems have several connected parts at the front and rear of the vehicle, which are divided into several stages designed to compress or break in response to the impact force. These multiple steps may include metal stampings or extrusion components that collapse in response to impact force.
However, conventional vehicle-mounted impact energy absorption systems cannot meet the increased demand for efficient manufacturing and design scalability due to their multi-component and staged conventional design. In addition, as the number of components that make up the impact energy absorption system increases, the complexity and cost associated with the manufacture, installation, and maintenance of these traditional impact energy absorption systems become excessive.
On July 5, 2021, Tesla filed for the "Integrated energy absorbing castings" patent, which was published on February 10, 2022. The patent describes single-piece casting familiar in the Tesla community.
Energy absorption systems are widely used in automotive crash structures, and include multi-cell pressing and multi-piece stamping, which mainly provide energy absorption by plastic deformation of the metal through dynamic crushing, warping, bending, etc.
Tesla has developed and patented a technology for the manufacture and use of cast energy absorption systems for the front and rear of a vehicle that can be integrated into the frame or be part of a larger monolithic casting. The disclosed technology eliminates the need for processes such as spot-welding, seamwelding, riveting, bolting, adhesive bonding, etc. by integrating the energy absorption system with part or all of the support structure through a single casting process.
In order to prepare a cast metal part according to some embodiments, a casting die is used to cast each energy absorbing part or system. Typically, the die cavity has two surfaces, that is, a first surface and a second surface, which are pressed together to form the final casting die. The casting die contains flow paths for the molten metal alloy that are formed within the casting die to carry the molten metal alloy to each hollow section of the die to create the final cast form. During the casting procedure, a molten alloy is rapidly injected into a die cavity which then cools to produce a cast solid metal product from the molten alloy metal. In some embodiments, the process uses high pressure die casting (HPDC) while the molten alloy metal is fed into the sealed die under pressure.
Unlike extrusions and stampings, the disclosed cast energy absorbing castings achieve energy absorption by generating progressive deformation and fractures in the casting that first initiate outboard and then propagate in an inboard direction during a crash event. The progressive crush ensures robust and repeatable crash performance.
© 2022, Eva Fox | Tesmanian. All rights reserved.
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About the Author
Eva Fox joined Tesmanian in 2019 to cover breaking news as an automotive journalist. The main topics that she covers are clean energy and electric vehicles. As a journalist, Eva is specialized in Tesla and topics related to the work and development of the company.