
Vol.05 Performance Damper
CHALLENGERS OF MONOZUKURI
Story of New Model Development
CHALLENGERS OF
MONOZUKURI
Story of New Model Development
Vol.05
Performance Damper
BELIEVE IN HUMAN SENSITIVITY AND WORK TENACIOUSLY. THE ANSWER LIES IN THE FIELD.
The cumulative production volume of the Performance Damper, which was developed as the world’s first such technology, has now exceeded three million units. We had an interview with the development team about the project.
Yamaha’s involvement in the four-wheeled vehicle business has been attracting attention, such as supplying electric powertrains to the prestigious racing car constructor Lola Cars, which competes in Formula E, the F1 of BEVs (battery electric vehicles), and collaborating with the British sports car manufacturer Caterham Cars to develop a new sports coupe, but that’s not all. Yamaha has a product that has set a milestone in its four-wheeled vehicle business. That is the Performance Damper (hereinafter referred to as the PD), which has achieved a cumulative production volume of three million units since 2004.
The PD is the world’s first vehicle body vibration damper for passenger cars and motorcycles that gently adjusts and absorbs minute deformations and vibrations of the body of running vehicles. The PD won numerous awards, including the Society of Automotive Engineers of Japan Award and the Ichimura Industrial Award. This damper is used by major automobile manufacturers and is also sold as an aftermarket part for passenger cars and motorcycles.
Now that about 20 years have passed since the mass production of the PD started, we held an interview with Group Leader KAMO Toshiaki, along with IIKURA Masahiko, SATOU Masahiro, and HARADA Toyoji from Development Group 41, Engineering Division 2, Automotive Development Section, Technical Research & Development Center, to ask about their efforts in developing the PD.

HIGH-QUALITY RIDE COMFORT THAT IS CLEARLY PERCEIVABLE AND ONE NOTCH ABOVE THE OTHERS WHEN COMPARED
To our surprise, a commercially available minivan was prepared at the interview location. The development team had brought the minivan so that we could test-drive it and experience the difference before and after installing the PD. The PD just looks like a rod. Since our in-house magazine staff are just average drivers, we had no confidence in telling the difference. Some staff members were hesitant, but the develop team strongly encouraged us to test-drive the minivan before and after the PD was installed, as if to say, “Proof is better than argument.”
As a result, all the magazine staff members noticed a clear reduction in noise and vibration, and also felt an improvement in ride comfort and steering stability. It was as if we had switched to a higher-class vehicle.
How can such a simple part make a huge difference? When asked why, the development team explained that very slight deformation of less than 1 mm is generated in the body of typical moving passenger cars due to the vibration. While suppressing the vehicle body deformation, the damping force of the PD quickly reduces and minimizes the vibration, eventually contributing not just to improving the ride comfort, but also to enhancing the tire grip feel due to the stabilized fluctuation. This also leads to excellent steering stability.

WORLD-FIRST TECHNOLOGY BORN FROM THE PASSION AND REALIZATION FOR CREATING BETTER CARS
How was the PD originally developed? The development division has been deeply involved in engine development and production for major automobile manufacturers. As cars evolve with the times, the team members have felt “Is there a way to take best advantage of the performance of the engines we have developed and manufactured for cars? That should lead to providing more comfortable cars.” In addition, they have been involved in research and development of automobile suspensions with the experience and knowledge they gained from the development of the OX99-11, a supercar equipped with an F1 engine that was Yamaha’s first four-wheeled vehicle which was supposed to be released in 1991. In 1997, Yamaha put into practical use an unprecedented suspension mechanism called REAS, which connects the hydraulic system of the left and right suspensions to balance both sides, contributing to improved driving performance and maneuverability. This mechanism was adopted by major automobile manufacturers both in Japan and overseas.
At that time, while working on the development of REAS, the development team, including HARADA and SATOU, who were in charge of the development and testing of REAS, felt that there might be a problem with the body performance of the commercially available cars provided by automakers. In general, to improve vehicle body performance, enhancing the rigidity was considered the standard approach. Thus, the development team was initially focusing on increasing the rigidity of vehicle bodies. However, Harada says, “When we installed a tower bar and patch to the vehicle body to increase rigidity, the vehicle at its cornering limit either slipped and slid or caused repulsion due to the accumulated deformation energy. This may have been acceptable as a racing car, but we were developing for passenger cars. Simply increasing rigidity did not result in a car that was comfortable to drive.”
Then, the development team came up with a hypothesis that it would be better to slowly rather than rapidly release the energy, and they continued testing. But as Harada says, “At that time, as we couldn’t even carry out advanced simulations, we just tried every approach we could think of,” the team had to keep searching for a solution. At some point, a member of development team back then came up with a great idea: “Wouldn’t it be better if we let the energy escape somewhere? What if we give the vehicle body some viscosity along with rigidity?” Then, they started to shift focus from rigidity to viscosity.
Based on this inspiration, the team created a viscoelastic rubber part sandwiched between metal plates, and it perfectly worked as intended. When they drove the vehicle with this new part installed, vibration quickly converged and a smooth ride was obtained even when the vehicle was pushed to the limit.

AT SOME POINT, A MEMBER OF DEVELOPMENT TEAM BACK THEN CAME UP WITH A GREAT IDEA: REDUCE VIBRATION AND DEFORMATION EFFECTIVELY. TAKE ON THE CHALLENGE THAT NO ONE HAS EVER FACED.
After further testing, however, another problem with the durability and stability of the rubber emerged. Again, another great idea hit the development team: “What if we add a shock absorber?” and they made a prototype. They initially fitted a single-tube shock absorber for four-wheeled vehicles with some adjustment, but Satou says, “Although the damping characteristics were good, the pressure of the high-pressure gas sealed inside the tube acted on the extension side and pushed the vehicle body, which eventually had a negative impact on both ride comfort and controllability.”
After further testing, however, another problem with the durability and stability of the rubber emerged. Again, another great idea hit the development team: “What if we add a shock absorber?” and they made a prototype. They initially fitted a single-tube shock absorber for four-wheeled vehicles with some adjustment, but Satou says, “Although the damping characteristics were good, the pressure of the high-pressure gas sealed inside the tube acted on the extension side and pushed the vehicle body, which eventually had a negative impact on both ride comfort and controllability.”
The development team determined that the technical key was to have only the damping force act on the vehicle body without applying pressure on it. By incorporating a rebound spring and balancing the spring force with the reaction force of the high-pressure nitrogen gas to neutralize the piston valve, they achieved eliminating the pressure on the vehicle body. Since damping force responds to minute displacements of the vehicle body, an ultra-low speed piston valve was developed that achieved minute movements with a stroke (displacement) on the order of µm (1/1000 mm), just less than 1 mm. It was generally difficult to control the ultra-low speed range with hydraulic pressure, but the development team realized it through a high-precision mechanism that reduced leakage. This is an important part of the PD.
Furthermore, they started to see some possibility of practical applications of the PD by using existing shock absorbers with appropriate modifications. Another major feature of the PD is that it is a highly cost-effective product.
The team also thoroughly reviewed the location for mounting the damper. Not only did they install the damper on the suspension towers, but also, as Harada says, the team tried everything, such as mounting the damper on the top part of the windshield of an open-top car, under the seat of a sedan, and installing as many as eight dampers in a car. He adds, “as a result of a considerable number of tests on every non-moving part of the body of various types of vehicles, we were able to obtain a consistent effect no matter where the damper was mounted.” In 2000, the development team applied for a patent on the PD. The PD was unveiled as the world’s first vehicle body technology in 2001, and it was finally adopted as a mass-produced product in April 2004.

HARDLY ACCEPTED EVEN WITHIN THE DIVISION.FIND A WAY OUT BY REPEATEDLY GIVING PEOPLE FIRSTHAND EXPERIENCE.
It’s no exaggeration to say that the PD is the fruit of the development team’s inspirations and experiments. However, it was not always smooth sailing. In fact, during the development phase, employees from most divisions were skeptical about the technology and effects from the aspect of sales, saying, “There is no way a deformation of less than 1 mm will have an impact,” even though the development team explained it to them. Since it was difficult to digitally demonstrate the physical quantity in micrometers for a moving object, the development team unanimously says, “Even the colleagues within our division did not understand the effect, so there was no option but to have them test-drive and experience the effect of the PD for themselves.”
As a result of their effort, several major automobile manufacturers are now using the PD. This is just because the effect of the PD is perceivable. The development team gradually gained trust by communicating with various people including employees of automobile manufacturers, repeating experiments, and sometimes explaining the effect to them using a handmade experience kit.
Of course, this PD is also adapted for use in motorcycles. In 2011, it was released as a genuine optional part for the TMAX. Currently, Y’S GEAR, one of Yamaha’s group companies, is expanding the range of PD-mountable models as a genuine accessory part. It also started supplying the PD to aftermarket parts manufacturers so that the PD can be fitted to other manufacturers’ motorcycles.
In 2024, a new PD with an aluminum body was also released. “It was originally designed for motorcycles, but repeated testing with an aluminum body eventually resulted in improvement in ride comfort. I was happy to see the PD being adopted for sport type motorcycles such as the XSR900, which places great importance on its maneuverability,” says Iikura with high expectation that the PD will also be used for a wide range of motorcycles.
The design of the new PD including its bracket for motorcycles was entrusted to GK Dynamics. Looking ahead to further sales expansion, this company is currently working on colorful PDs using anodized aluminum and paying extra attention to the coloring method.

DELIVER PRODUCTS THAT HAVE SENSORY PERFORMANCE THROUGH DEVELOPMENT WHERE HUMAN SENSIBILITY IS OF UTMOST IMPORTANCE
When asked what they put importance on in the development, Harada says, “I myself repeated test-driving with many people, including not just top drivers, but also ordinary drivers to exchange opinions. I gathered their opinions and thought about what the next product should be. New ideas and inspirations don’t come to you easily if you are stuck in the office. That’s what I’ve been thinking so far,” and Kamo says, “I’ve been told, ‘Just drive the car. The answer lies in the field.’ I want to pass on to younger engineers the methods and knowledge of our senior engineers, who put importance on driving cars regardless of whether you belong to a designing division or a testing division.” They express their attitude toward manufacturing that values the field and human sensitivity. Since you can’t see micrometer-scale deformations of a vehicle body or damping force of the PD, it’s difficult to understand such phenomena, but you can actually feel their effects. It should be no surprise that the PD was finally launched onto the market because the development team valued and utilized rich human sensitivity.
As manifested by the aluminum performance damper being introduced, the development team’s evolution never stops. Let’s look forward to further progress in the future.
