

Item 5. Developing the Lexus

The 'Yet' concept and 'Fixing problems at the source'

In September 1989, TMC started operation of Lexus, a luxury car sales network in the United States. Development of the flagship model of this sales network, the first-generation LS 400, had begun in 1984 under the "Circle-F" project, the "F", written with a circle around it indicating a completely new model, standing for flagship. There were two factors behind the establishment of this new channel. First, full-scale local production in North America of other models would leave some room in the import quota under the voluntary restrictions. Second, when customers of Toyota cars upgraded to higher-end cars, they ended up switching to Mercedes or BMWs because no luxury Toyota models were available.

The project members spent several months in the United States doing genchi genbutsu (go to the source to find the facts), investigating in detail the lifestyles of those who owned luxury cars, as well as their expectations and requirements of luxury cars. Their findings confirmed that a luxury vehicle: 1) must possess a status and prestige feel, 2) must be of high quality, 3) must maintain a high resale value, 4) must offer advanced performance, and 5) must provide a high level of safety.

With "Creation of a world-class high-performance luxury car" set as the basic goal, the project members worked with all related groups within TMC, including those responsible for technology development, production engineering, manufacturing, and sales, as well as group companies and suppliers to achieve it. During the development process, the two concepts of "Yet", in which even two conflicting elements were allowed to be included without compromising either one and "Fixing problems at the source", in which any problem that occurred had to be corrected at its very source, were thoroughly enforced as the project members took on the challenge of exploring uncharted territory.

In May 1987, following eight previous proposals, the final design of the LS 400 was approved and testing was commenced of a prototype equipped with a 4-liter V8 engine. To reduce vibration and noise, a vibration-damping steel sheet was used in the body, and a high-precision manufacturing method was developed for the propeller shaft. Additionally, to achieve top-level aerodynamic performance, indicated by a low drag coefficient of 0.29 despite the sizable design, the window glass and door handles were designed to be flush with the body.

TMC's Tahara Plant, which was responsible for producing the new model, introduced a new assembly line control system based on distributed processing with the start of Lexus production. Unlike the conventional Head Office-managed control method, this new system used servers to separately control individual lines for bodies, assembly, etc. Since this system allowed detailed production instructions to be sent to the individual lines on a timely basis, any problems that occurred in the lines could be addressed immediately.

To improve vehicle quality, the Production Engineering Group developed a method of laser-welding multiple body steel sheets with different thicknesses and rustproofing treatments and then stamping out the integrated pieces. For casting the cylinder block, the group also implemented a method that improved strength and shortened casting time by lowering the pressure inside the mold to increase the pouring and charging efficiency of aluminum at low temperatures. After roughly six years of development, involving some 50 clay models, approximately 450 vehicle prototypes, and driving tests covering more than 3.5 million km, the LS 400 was completed.

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