Toyota Boshoku Corp disclosed the "TB-NF100," the framework of the front seat used in Toyota Motor Corp's new "iQ" compact car.
Toyota Boshoku has been developing new frameworks in the hope that they will be commonly used in several vehicles. The TB-NF100 is the first such product. The company plans to utilize the basic structure of this framework and efficiently develop frameworks for other models.
The basic parts of the new framework were developed on the assumption that they would be used in a wide variety of models. The framework is applicable to compact cars such as the "Vitz" as well as large sedans including the "Crown," according to the company.
In respect to K-cars, "It may be difficult to use this framework without modification due to its cost," said Mitsuyuki Noguchi, vice president and director of the Technology Development Division at Toyota Boshoku Corp. It is also difficult to apply the framework to luxury vehicles such as the "Lexus" without modification, but its basic principles are applicable, the company said.
Toyota Boshoku did not specify the distinction between the basic parts (fixed parts) and variable parts.
"We would like to refrain from clarifying the distinction because it will become clear when the next product (utilizing the basic parts of the TB-NF100) is completed," Noguchi said.
However, it is estimated that the lower arms (panel-shaped parts on the sides for supporting the seating surface), the side panels (parts used in the sides of the seatback), the slide rails and the slide table will be fixed and the headrest and parts for connecting the basic parts will be variable.
For example, the headrests used in the iQ are not adjustable. But, in the future, the headrest adjusting function will possibly be required for the iQ as well as for other models. To address this issue, the headrest of the TB-NF100 can be replaced with an adjustable one without changing the basic parts.
In respect to the slide rails, which can be installed inside or on the floor, the framework can be modified by using the basic parts and replacing fastener components or changing their fastening positions.
In developing the new framework, Toyota Boshoku focused on
(1) reducing the thickness of the seatback,
(2) weight and material usage reductions in respect to the entire framework,
(3) the improvement of riding comfort and
(4) the improvement of operability (the back and forth movement of the seat).
In respect to item
(1), the thickness of the seatback was reduced by 40mm compared with the existing seats in the Vitz through changes in the overall shape of the framework. This reduction makes it possible to shorten the vehicle length without changing the distance from the seatback to the rear seat.
The thickness reduction of the seatback was extremely important for the iQ in particular, because it was designed under the concept of being "shorter than 3m."
(2) was achieved by reducing the number of parts and fastening points through extensive unification of multiple parts. Every possible effort was made to unify the independent panels. Connecting pins and brackets were unified with the panels or eliminated. Through these efforts, the number of parts and fastening points were reduced by 25% and 20%, respectively, while the mass was reduced by 15% and the yield was increased by 18% compared with Toyota's "Corolla."
These comparisons were made with the Corolla, instead of the Vitz, because quantitative comparisons were difficult with vehicles other than the Corolla, which shares a similar installation method with the iQ, according to Toyota Boshoku.
As for item
(3), the framework was designed based on the physical characteristics of Japanese, American and European people, assuming it would be used in vehicles marketed all over the world.
(4), the lever (slide lever) for moving the seat back and forth was relocated from the front bottom to the side of the seating surface. To operate the slide lever located in the traditional position, the occupant has to bend over no matter whether that person is seated or standing. But, with the new position of the lever, a seated occupant can operate it without bending over and a standing occupant only needs to slightly bend down to operate it.