A Seat That Lives Up to the “Supercar” Label

Acura NSX

SymanskiThe NSX is the flagship (top-of-the-line) model of Honda's Acura brand, and I still remember that the first NSX had a major impact on the industry when it made its debut. I believe that it was an important model in car history.
When I was put in charge of the development of the seat for the project to revive the NSX after a 10-year absence, I felt a real sense of responsibility and thought, “I must develop a seat that will raise the status of the NSX even higher so as not to tarnish its name!”
Only the basic design of the frame was created in Japan, and the subsequent development was transferred entirely to the project team members in North America.

SymanskiThe development concept for the NSX proposed by the customer was a “human-centric design” as well as high performance and ease of handling for the driver, coupled with a greater comfort and safety.
To develop a seat based on this concept, since the NSX is a supercar model, we aimed to deliver both hold (the ability to hold a body in place) that can support a passenger even during higher levels of swing speed and advanced comfort.
Although we undertook research on a number of seats in supercar models of rival cars, which we set as our benchmark, we felt that while many of them showed an extremely good hold when they drove around a circuit, comfort was somewhat sacrificed.
Generally speaking, if the focus is only on the hold, comfort will suffer. It is not that difficult to satisfy either of these aspects individually, but it is very difficult to satisfy both hold and comfort at a high level. We have imbued the NSX seat with the technologies and expertise that we have cultivated, while also paying a great deal of attention to comfort.

InoueFor example, if we want to increase the hold, we just need to add a large bolster^*1. However, it would get in the way during everyday driving, and comfort and the ability to get in and out easily would be lost. We therefore investigated the fine balance between these functionalities in various patterns by changing the surface shape of the seat and the softness of the urethane (cushion material) using simulation software. We then created a large number of prototypes and checked with in-house experts who evaluated overall comfort regarding the behavior during cornering that is unique to the NSX, the ability to get in and out of a sports car with a low height, and various sensations including driver fatigue after long periods of driving in order to finish the seat.

*1 Bolster: The portion that bulges out on the right and left sides of the seat face and the backrest section of the seat.

IkezawaWe paid particular attention to the bolster section. We layered urethane materials with different degrees of softness and achieved the hold best suited to sports driving, while simultaneously accounting for differences in driver physiques.
In addition, to give the car even more of a luxurious feel, we used wadding material^*2 two or three times the thickness of the type normally used for the bolster. I believe that this enhances the high-quality unique to a luxury car through a seat that is soft to the touch from the moment the driver gets into the car.
However, we had a hard time achieving “sharpness,” one of our design concepts, because when we used thick materials, the seat looked bulky.

*2 Wadding material: Spongy material between the surface material and urethane

IkezawaIn addition, it is difficult for an ordinary sewing machine to make a uniform line along the curve of the decorative stitching^*4 on the Alcantara®^*5 surface material at the center of the seat face because the area to be sewn is very long. We therefore installed pre-programmed automatic sewing machines to create stitches with a beautiful curve and a uniform width.

*4 Decorative stitching: Sewed section for decoration
*5 Alcantara®: Suede-like artificial leather with superior durability and ventilation

SymanskiWeight reduction is also an important challenge for sports cars. To contribute to weight reduction, we used a composite seat frame that utilizes the advantages of steel and aluminum for the seat frame, taking into account strength, processing and productivity.
If different metals are bonded, however, a difference in electrical potential^*6 will arise in that portion and cause corrosion. Accordingly, we also adopted bonding technology for composite materials.

*6 Difference in electrical potential: Each metal has an electric property of a specific value, and the greater the difference in electric properties, the more easily corrosion will occur when different metals make contact.

InoueFor the section that supports the driver’s buttocks (hips), we used a frame structure that used a press-formed aluminum board, which enabled the weight to be reduced by almost 1kg when compared with steel.
We also received a request from the customer to maximize the space between the car height and the hip point^*7 as much as possible. By using this structure, we were able to reduce the weight and lower the hip point as well.
The reason why it is difficult to lower the hip point is that if we set the frame that supports the driver’s buttocks low, the available area of the seat face will be limited, which will mean that there is nowhere to insert the wire harnesses (wiring) and other features. Because modern seats contain many electronic devices, such as side airbags and motors to adjust the position and angle of the seat, wire harnesses are spread out under the urethane to control them. Accordingly, the wiring, and even the interference when the seat moves, are carefully taken into account.

Thanks to this frame structure, the NSX ensures that the driver’s buttocks are as close to the floor as possible. We had a hard time designing the wiring of the wire harnesses, however.
Other than the wire harnesses, we also examined the thickness and softness of the urethane to make it as thin as possible without any loss of comfort. As a result, we have achieved a low hip point that is suitable for a supercar model as well as the comfort of a luxury car.

*7 Hip point: The position of the driver’s hips when he or she sits on the seat. Although a lower height and lower center of gravity are believed to be advantageous for sports driving, they limit the car's interior space. Accordingly, occupants will not fit if the seat does not have a low hip point.

SymanskiBecause the NSX is a high-end model, the value expected by customers is also very high, so we paid more attention than ever before to the external quality as well.
For the materials for the surface, for example, we used high-quality materials such as Milan leather and Alcantara®, even in the standard specification. We have also developed a high-grade specification that uses semi-aniline leather, a type of high-grade leather often found in European luxury cars.
I believe that because the surface coating^*8 of the semi-aniline leather has a particularly thin finish, the driver will be able to feel the original texture and soft touch of the leather.
For normal leather, small scratches become invisible in the working process of surface coating. With semi-aniline leather, however, even minute scratches are noticeable because the coating is thin. We therefore select smooth, high-quality parts and conduct especially stringent inspections of the surface state.

*8 Surface coating: Generally, a solid coating is applied to the leather of automobile seats to make it resistant to direct sunlight and abrasion from clothing. If the coating is thick, the leather is stronger, but the original texture of the leather is lost.

IkezawaIn addition, the material is also softer than normal, so we make it with extreme care so as not to scratch it while sewing. Even when we transport trim cover to the assembly plant after sewing, we deliver it between plants using a shipping rack designed just for the NSX.
These stories of the surface material and sewing are just a few examples, and we make the seats in the hope of delivering the highest quality in line with the automobile rank of the NSX to customers, even if it takes us a lot of cost and effort.

InoueAlthough the seats for the previous NSX model were produced in a specialized plant in Japan, the seats for the new model are manufactured in the United States, as are the vehicles. It was also a challenge to produce high-quality seats at our existing plant in North America.

SymanskiProduction hurdles, such as leather that we had not previously dealt with and a complex surface shape, were high, but we designed a compact production line for a small number of people dedicated to NSX within the existing plant.
While we were able to significantly increase the assembly accuracy in the compact production line compared with the large one, the workload per person is heavier, and the level of difficulty of the assembly is also higher. We therefore formed an assembly team for the seats for the NSX by selecting highly skilled staff. A select team of specialists manufacture the seats with the utmost care. This method has enabled us to supply the highest quality seats that surpass those of the previous model.