- Semi-automatic transmission with only one actuator
- Combination of automated shifting and centrifugal clutch
- Designed for use in existing engine and transmission concepts
Yamaha continues to drive forward the development of automated shifting systems. While semi-automatic and automated transmissions have long been a niche product, they have recently become established among several manufacturers. Yamaha has also been following this development for many years and is now working on a particularly simple and cost-effective solution that is to be positioned significantly below the previous Y-AMT technology.
From YCCS to the current Y-AMT system
Yamaha gained experience with automated gearboxes early on. Around two decades ago, the FJR1300AE featured the YCCS system, in which the clutch and gear changes were operated electromechanically. This basic principle lives on in today’s Y-AMT, in which one actuator is responsible for the clutch and another for the shift mechanism. An electronic control unit allows for both fully automatic shifting and manual gear changes via a button.
The current Y-AMT design is already available in several models, but is still based on two separate servomotors. This is precisely where the now patented further development comes in.
One actuator for clutch and gearshift
The new concept envisages clutch actuation and gear changes being performed using just one electromechanical servo. This actuator replaces the conventional foot-operated gear lever and engages directly with the gearbox’s toothed shift shaft. The shift movement is therefore essentially the same as with a classic manual gearshift.
The same actuator is also connected to the clutch mechanism via an additional mechanical link. When a gear change is initiated, the clutch disengages briefly and then re-engages immediately. The entire shift process is therefore synchronized and does not require a separate clutch actuator.
Revised clutch mechanism as the key
To ensure that this system works in both shift directions, Yamaha has opted for a modified form of the clutch actuation mechanism. Instead of a single-sided cam, a flat, semicircular design is used. This reliably relieves the clutch during both upshifting and downshifting.
Regardless of whether the shift impulse is up or down, the clutch pressure is reduced identically. As soon as the shift operation is complete and the actuator returns to its starting position, the power connection is automatically reestablished.
Centrifugal clutch for starting and stopping
However, purely shift-dependent disengagement of the clutch is not sufficient to enable comfortable starting or stopping. Yamaha therefore combines the system with a centrifugal clutch. This opens automatically at low speeds and closes again as the engine speed increases.
When stopping, the gear can remain engaged without the engine stalling. When starting, the centrifugal clutch ensures smooth engagement without the need for manual control. This principle is already familiar from other semi-automatic concepts and adds a crucial function to the simplified Y-AMT solution.
Design for many models and low costs
According to the patent description, the system is deliberately designed so that it can be integrated without fundamental changes to existing engines and transmissions. The shift actuator is located externally on the transmission, and the centrifugal clutch can largely replace classic clutch concepts.
The reduced number of components should not only make the technology cheaper, but also suitable for smaller and simpler models. Motorcycles for beginners or new target groups in particular could benefit from the easier operation, provided Yamaha transfers the technology into series production.
Whether and when the simplified semi-automatic transmission will actually appear in production models remains to be seen. However, the patents clearly show that Yamaha is pursuing the topic of automated transmissions in the long term and in various price segments.
What does this mean for me as a motorcyclist?
The simplified semi-automatic transmission technology could make riding a motorcycle much more relaxed, especially in city traffic or when stopping and starting frequently. Clutch operation and gear changes would be partially or fully automated without sacrificing a classic motorcycle transmission. This can make operation easier, increase concentration on traffic and the road, and reduce the risk of stalling when starting off. At the same time, the familiar riding feel of a manual motorcycle is retained, as no continuously variable automatic transmission is used. Especially for beginners, those returning to riding, or riders who are on the road every day, such technology could simplify access to motorcycling without forcing fundamental changes.
→ This article is part of our comprehensive overview of patents and future technologies – find all developments in our Patents and Future Motorcycle Technology overview.
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