THE PEOPLE BEHIND THE MX-5 INTERVIEW
  • Yoshinori Takeuchi & Naoko Motoyoshi Chihiro Furukawa Vehicle Development Div.
  • Takayuki Kimura & Hiroshi Kawata Vehicle Development Div.
  • Katsuaki Nobukawa & Miyoko Ishikawa Drivetrain Development Dept, Powertrain Development Div.
  • Yukifusa Hattori NVH Performance Development Dept, Vehicle Development Div.
  • Tsukasa Hoshino & Kenji Sasaki Powertrain Development Div.
  • Yukiharu Asano Clay Modeler, Design Div.
  • Masashi Nakayama Next MX-5 Chief Designer
  • Shinichi Yasui Production Planning Dept, Production Engineering Div.
  • Yukio Nakamura Product Planning Dept, Product Div.
  • Tetsuo Fujitomi Powertrain Planning Dept.
  • Hitoshi Takamatsy Deputy Program Manager, Vehicle Development Promotion Dept.
  • Nobuhiro Yamamoto Program Manager

Relaxation and a sports car spirit drawn
from a completely new idea have been poured
into a part of the 4th Generation MX-5

Yoshinori Takeuchi , Naoko Motoyoshi
In charge of Seat Development for the 4th Generation Mazda MX-5
Vehicle Development Div. Interior & Exterior Components Development Dept.

Chihiro Furukawa
In charge of Craftmanship Development for the 4th Generation Mazda MX-5
Vehicle Development Div. Vehicle Testing & Research Dept.

Relaxation and a sports car spirit drawn from a completely new idea have been poured into a part of the 4th Generation MX-5. That part is the two seats with their ingenious, finely designed net material which wraps around the driver and passenger.
Naoko Motoyoshi, who led development of the seats, is a specialist in physiological psychology. The mind and body, while preserving their consummate relationship, are what shape each and every human. When the mind is uplifted, the body flushes, and when the body feels hurt the mind becomes saddened. Motoyoshi, who was involved in research in this field at university, became a member of Mazda with the desire of creating the ideal seat for automobiles. And for the 4th Generation MX-5, she created the ultimate, high quality seat. It is a seat for a sports car full of unique ideas unimagined by anyone else, and one which has been achieved for the first time based on an extremely high level of technology.
"The concept of constructing seats using netting had already been researched as a theme for advanced development. However, at the time when development of the 4th Generation MX-5 began, there remained multiple challenges in reaching the point at which we could be satisfied. Despite that, I felt the seat had great potential and I came to the decision that the MX-5 seat could only be completed by addressing the challenges."

We wanted to raise the ultimate feeling of
Jinba-ittai to a new dimension

So what is driving pleasure to the heart? What is crucial is not only the hold ability of the seat which allows concentration on driving, but also the comfort which makes you want to continue taking each and every curve tirelessly. For Motoyoshi, who knows completely the comfort produced by the harmony of mind and body, it was just the possibilities which could be provided by this new seat that were appropriate for the MX-5.
It was also Yoshinori Takeuchi, Motoyoshi's boss and the man behind the development of seats for many Mazda models, who was convinced that the time had come for this seat to make its debut.
"It was commonly accepted that for a seat on a sport car to achieve the aim of supporting the body firmly, it should have a firm fit and large vortex at the seat cushion and seat back which overhang largely to suppress side movement of the body. This was the direction we pursued when I was in charge of developing the seats for the 3rd generation MX-5. However, with this type of seat, its ability to fit the body perfectly is the precondition in demonstrating its performance. Such seats, which are built on the concept of putting the occupant's body within a frame made of hard material, present huge difficulties in fitting customers of various physiques.
The concept for conventional sports car seats, which puts people into a hard, narrow seat, had limitations under the philosophy of the MX-5, which aims to be a car that will make anyone happy. We wanted to raise the ultimate feeling of Jinba-ittai to a new dimension. We had to innovate in order to protect. Thinking this way, we felt that the time was right to move ahead on adopting the seat with the net we worked on in advanced development."

Creating the ultimate seat, not with the usual metal springs and urethane pads, but by carefully adjusting the tension of the net material itself

Just as they expected, the difficulties in developing a sports car seat using net material were extreme. First, Motoyoshi measured the distribution of load across each area of the seat.
“On the surface of the seat where the body and seat touch, there is actually a complex load distribution occurring from the places where a heavy load is applied to the places where it touches only lightly. And when you start to drive the car, the load distribution continues to change due to the body being shaken by the undulations in the road surface and the addition of G-force during acceleration, deceleration, and cornering. You will feel discomfort if a strong load continues to be applied in any one part of the body and, on the other hand, areas with too little load are disadvantageous in obtaining the necessary hold feel.
Because the net naturally follows the body’s shape just like a hammock, discomfort from strong pressure being applied to a part of the body can be avoided. However, with a uniformly woven net, it expands only in the areas where a heavy load is applied, causing the body to sink unnaturally and is unable to support the load changes occurring during sporty driving.”
Motoyoshi took on the challenge of creating the ultimate seat, not with the usual metal springs and urethane pads tuned to the required hardness, but by carefully adjusting the tension of the net material itself. "At a casual glance, the seats for the 4th Generation MX-5 look as though they have been made from a uniform net material. But actually, the thread thickness, material properties, and intricacy of the weave change continuously throughout the structure.
The difficulties with the development of this net were especially intense. I consulted with suppliers any number of times. Our discussions continued to be tense with words such as, "You're asking the impossible" and "This is the limit of what's possible". I understood that a very high level of technology was required, to the extent that they might pull out. But I also understood that if I couldn't overcome this obstacle, the ideal seat for the MX-5 could never be completed."

Driven by Motoyoshi's passion for this seat, the development of the net finally started in full. And after a short while, trial productions of the complex weave of the net material arrived. Whenever a trial production arrived, Motoyoshi rushed to set it on the seat frame and tested the seating feel. Using measuring instruments, she meticulously examined the differences from the ideals she had conceived. Then she attached memos crammed with requests for improvements and ordered the next trial production. The development of a net material which no one had ever before accomplished became a long-term battle repeatedly taking one step forward and then one step back.
"Development of the net alone took nearly 3 years. The actual number of trial productions alone is 60 plus. There are even more plans on my desk… They are countless…" Takeuchi added some words while looking at the expression on Motoyoshi's face looking back on her efforts. "Should we also consider a seat with a general structure in case it becomes impossible to achieve the ideal one?" I actually asked her this question because I was concerned that she was going a little overboard on the seat development. But it was only my imaginary fears. Slowly but surely, she endowed the seat with a soul suitable to the MX-5 and completed it at long last."

Motoyoshi's last challenge was how to prevent the area at the center of the seat cushion around the hips from sinking deeply.
"The impetus to the solution was the reed-shape concept that I conceived. I lined the seat cushion lengthwise with a low-shrinkage net which was cut into a long, narrow shape much like a reed. At first, I tried to solve the problem using different methods, but I couldn't produce any of the results I expected. I learned that people really can come up with a lot of ideas when they face a predicament. Of course, it took a lot of time to choose the materials and decide on the shapes after the concept was decided".
So, a seat with an unprecedented structure, never before achieved, was completed. It is a seat full of the passion of Motoyoshi who emphasizes more than anything else the comfortable relationship of the mind and body.

This car inherits the indisputable lineage of the MX-5 and represents the heart of Mazda

If you ever want to come close to an 4th Generation MX-5 and you have the opportunity of visiting a showroom, go ahead and slide into one of the seats which have achieved both relaxation and a sports car spirit at a high level. We want you to imagine yourself driving the car under a bright, blue sky. Then, take a long, slow look at the entire MX-5 body and see that this is certainly a car filled with the best of Mazda's vehicle-engineering spirit.
And at that time, we would be happy if you would take a moment to think of one more person; Chihiro Furukawa. Furukawa, who is a member of the craftsmanship development group, played an indispensable role in harmonizing the passions of the countless people behind the MX-5 development and accomplishing it as a complete Mazda model.

When you see the 4th Generation MX-5, and when you settle into the supple seats and head off to town, you will realize that this car inherits the indisputable lineage of the MX-5 and represents the heart of Mazda through all of the scenery your eyes take in, all of the textures your hands feel, and even the movement of the wind tossing your hair slightly.
It is of course the fruit of the minds and craftsmanship of all the engineers and designers who poured their hearts and souls into the development of this car. However, we cannot forget Furukawa who harmonized all these factors to produce a feeling of unity as a single product.
Furukawa, who was active as a leading player on the Mazda volleyball team, does not have any special skills as an engineer or designer. Truth be told, she is not a deep car enthusiast. But she harmonizes with her fellow warriors on the court who bounce about their lively personalities and talents, and she has acquired the skills to gather energy for various goals through her daily hard practice on the volleyball court. We cannot afford to forget her efforts to promote improvements to finely develop the overall harmony of the car called the MX-5. For example, she kept a close check on not only the gaps occurring around doors and the bonnet, but also the cohesiveness in textures of the interior and exterior, and even fine details like the slightest diffraction and leakage of light from lamps and the dashboard illumination. And once she decided that something was not suitable for a Mazda vehicle or it deviated from the ambience of the MX-5, she would communicate the fact to the MX-5 engineers who take such great pride in their work, and at times even to the program manager Yamamoto, responsible for the overall control of the development.

To all the MX-5-loving fans, thank you for waiting. After a long period of uncompromising development in which development teams poured their inexplicable passion and looked backed on themselves with severe eyes, the 4th Generation MX-5 has finally been completed. We'd like you to enjoy the whole of the 4th Generation MX-5 from the bottom of your hearts. This car truly symbolizes Mazda's vehicle-engineering philosophy and puts smiles on people's faces all around the globe.