The ultimate boundary of mechanical efficiency.
Rolex cheap introduced Chronergy—essentially a mechanical ecosystem that can achieve the best mechanical performance—and cal. 3255 of the top Day-Date 40 that debuted in 2015.
Six years later, Rolex has almost upgraded the entire series, equipped with the latest generation of Chronergy calibrators. The 32XX series includes its most affordable products. Chronergy movements can be found in Datejust (cal. 3235) and Oyster Perpetual (cal. 3230) and entry-level sports watches, such as last year’s Submariner ref. 124060 (cal. 3230).
Chronergy consists of 14 patents covering all aspects of movement from the power source to the regulator, but the basic element is the escapement. The Chronergy escapement actually continues a long-forgotten journey that began about 50 years ago on the other side of the world.
300 years old still talking
The lever escapement invented by Thomas Mudge (1715-1794) in the mid 1750s can be said to be a necessary iteration of the deadbeat escapement, once it is miniaturized for use in watches. George Graham (1673-1751) envisioned it as an improvement of the anchor escapement in the pendulum clock, which is not suitable for the fine proportions of the watch.
In the lever escapement system, pulses are provided to the balance wheel through the lever, and the lever is pushed by the force of the pallet fork jewel where the teeth of the escape wheel contact the lever. The lever escapement is an independent escapement, which means that after the energy is transmitted through the impulse jewel, the escape wheel locks the balance wheel so that the balance wheel remains free during all its supplementary strokes.
The linear layout of the lever escapement is still in use today—the balance wheel, lever, and escape wheel are in a linear layout—in fact, it has a history of several centuries, dating back to 1786, by Jean Moise Pu Designed by Sete (Jean Moïse Pouzait, 1743-1793).
The teeth of the escape wheel as we now know it resembled the foot of a club. It seemed to appear around 1860 and quickly became a de facto geometric shape. Subsequently, it was actually blasphemous for manufacturers to deviate from the geometric shapes prescribed in the industry bible at the time, such as the modern horology paper in theory and practice by Claudius Saunier (1887) or Leopold Théorie général de l’horlogerie (1950) de Fuse in Germany (Leopold).
The lever escapement has proven to be sturdy, reliable and easy to manufacture on a large scale, making it the main escapement for watches and pocket watches. However, the lever escapement is far from perfect, especially the effect of the change in friction of the pallet fork, which has led to many attempts to improve or novel escapements over the centuries.
In the past few decades, people have been trying to use new materials such as diamond-like coatings and silicon carbide to reduce the changes in friction over time, but there have been few basic developments, especially in terms of optimizing the geometry of the escapement. The famous coaxial escapement invented by George Daniels (1926-2011) is the only new escapement that can be mass-produced. However, it has only one brand, Omega, in mass production.
Although the variety of new escapement designs is a welcome development, the key is to re-examine the basics, especially since technology has become a real boost for technological development. Modern mechanical dynamic modeling, computer-driven analysis techniques, and high frame rate photography enable insights and optimizations that were impossible before.
The purpose of the escapement development also evolved from the times of Graham and Puset. In such a world, brands such as Omega now maintain an average daily rate of less than five seconds on an industrial scale. Rolex is slightly better. The development of the escapement system is no longer about timing, but more about extending the power reserve. .
We have discussed the trade-offs in the movement design, showing that for a given energy, the balance power and power reserve change inversely proportional to each other. The simple solution to extend the running time is to reduce the power of the balance wheel, but at the cost of possibly affecting the timing ability. Another option is to increase the efficiency of energy transmission, which starts with the escapement.
The first step in adjusting the geometry
Perhaps it was only during the fiercely competitive observatory trials in the mid to late 1960s that designers began to question and adjust the geometry of the lever escapement. In pursuit of greater inertia of the balance wheel, the beat frequency began to rise, and it was found that the energy transmission efficiency in the escapement decreased.
Specifically, it was discovered that when the movement exceeds the widely accepted standard for the frequency of the balance wheel, which is 18,000-21,600 beats per hour (bph), and increases to what is commonly referred to as “high beat” or 28,800 -36,000 bph, the traditional lever tooth escapement The wheel transmission efficiency dropped from about 40% to 30%. The result is a decrease in the amplitude of the balance wheel-which is an undesirable result of stable timing.
Several solutions have been proposed: the mainspring torque can be increased to maintain the amplitude, a lower amplitude can be accepted, or the balance inertia can be reduced.
For its own reasons, these are not desirable. Higher mainspring force will increase the wear of the drive train, and the loss of amplitude will increase the position timing error. On the other hand, when the size of the mainspring is fixed, reducing the inertia of the balance wheel to achieve a good amplitude, while reducing the power supply efficiency will mean reducing the power and power reserve of the balance wheel.
The first published work I could find that thoroughly looked at this issue from the ground up—especially the ideal geometry based on higher frequencies and friction effects—was carried out by an engineer from the watch manufacturer who was an outsider in the industry at the time. , Even upstarts. Kenji Abe of Suwa Seiko, one of Seiko’s operating companies, obtained US patent US3628327A for its “horseshoe lever escapement” in 1971. Replica watches Price
At some point in the late 1960s (the patent was filed in 1970), Abe conducted a first-principles static analysis of the contact geometry between the escape wheel teeth and the pallet fork, taking into account the torque generated by friction. The impact of the balance.
When explaining the operation of the lever escapement, an often overlooked fact is that after the pallet is unlocked, there are two different types of pulses. The first action (impact A) is to push the locking beak of the escape tooth against and along the impact surface of the tray.
Abe inspected two types of pulses and the condition of the inlet and outlet trays. He found that the integral (or sum) of the moments multiplied by the ratio of the angles they move on both sides of the contact is the key.
He further discovered-this is Abe’s most notable discovery-when the surface length of the escape wheel teeth is the same as or up to twice the length of the pallet fork, the highest transmission efficiency will be obtained. This compares to the more typical ratio of escapement gear teeth between half to four-fifths of the length of the pallet fork. This shows that longer-than-usual club feet on the teeth and shorter-than-usual trays have brought benefits-this is the exact opposite of what Defossez’s timepieces proved.
Abe’s discoveries about geometry never seemed to apply to Seiko’s serial production movements, and it was too late for the movements used for the observatory test. These were all cancelled after Japanese watches swept the board of directors in 1968. Perhaps this is just the emergence of quartz technology, which means that the investment of resources to pursue a more precise mechanical escapement is considered to be commercially meaningless.
Interestingly, despite the renaissance of mechanical watches and the recent pursuit of precision, the modern Grand Seiko Hi-Beat movement eschewed Abe’s approach and instead relied on the traditional escapement geometry, despite its low inertia characteristics, namely hollowing. The escape wheel and lever produced by a photolithography technique called MEMS.
Bravo Abe-san and chapeau Rolex
The combination of all its functions makes the movement equipped with Chronergy 40-50% more autonomous than the previous generation movement. This improvement is exactly the same as the power reserve of the Chronergy movement claimed by Rolex as “approximately 70 hours”.
Based on our Horological Density Factor measurement and assuming the same balance ability as cal. Equipped with Chronergy’s 313x movement. The 323x series broke the 25000 kJ/m 3 barrier-an outstanding performance (easily defeated Omega’s flagship Master Co-Axial cal. 8500, perhaps the most comparable alternative).
But in addition to Chronergy’s performance improvement, it is gratifying that it can still enhance the traditional lever escapement. Equally satisfactory is that Chronergy’s key advancements originated about half a century ago, when the research of emerging Japanese watch manufacturers was at the end of their pursuit of mechanical precision.
Now, these ideas have been carefully re-examined, and further developed through clever improvements, and finally adopted by the high-quality mass production master swiss Rolex as the new normal.