Internal structure of automatic watch

Mechanical watches can generally be divided into the following two types: manual and automatic watches. The power source of these two types of machines is driven by the spring inside the movement, which drives the gear and then pushes the watch needle. However, the power source is different in the way. Mechanical watches with hand winding rely on hand power. The thickness of the movement is thinner than that of conventional watches with automatic winding, and the weight of the watch is relatively light. "The automatic chaining watch uses the automatic rotating disc of the movement to swing left and right to generate power to drive the spring, but the thickness of the watch is relatively larger than that of a hand wound watch.".

The gear train of watches, especially the main transmission gear train, widely uses a so-called circular tooth shape. This tooth shape is an evolution of the wiring tooth shape. Due to the difficulty of machining pure cycloidal tooth shapes, circular arcs are used instead of cycloids, also known as modified cycloidal tooth shapes, which can make the minimum number of teeth on the gear shaft to 6, thereby achieving a large transmission ratio when the number of teeth on the wheel is not too large, which is extremely beneficial for reducing the center diameter and for high-frequency watches. The transmission efficiency is relatively high, generally reaching around 95%. Due to the small size of the watch's movement, the energy stored in the cassette wheel assembly is not large. If the energy loss is too large, it will directly affect the timekeeping quality of the watch. It is highly sensitive to machining errors. For example, tooth shape error and center distance error can cause changes in meshing characteristics. Because its tooth shape is determined by a pair of meshing gears and modules, the number of teeth and modules are different, and the hobs and milling cutters used are also different.

The composition is very simple. Swiss watches have relatively few parts, mainly composed of escapement wheels, escapement fork components (including escapement fork, shoe in, shoe out, fork pin, fork shaft), double disk components (double disk, disk pin), and limit pins on the main clamp plate. However, some watches do not use limit pins, but instead mill two bosses directly into the main or fork clamp plate to limit the position. Others use a nail protruding from the escapement fork component to insert it into a hole in the main clamp plate to limit its position on both walls of the hole. This type of escapement mechanism is called a fork shoe type escapement mechanism, which is divided into two types: a straight fork type and a side fork type. The former is that the escapement wheel shaft hole, the escapement fork shaft hole, and the swing shaft hole are in one line; The latter is that the connecting lines of these three holes have a certain angle. Although the two forms are different, their composition and working principle are the same. Mainly used in medium and high grade watches.

The cycloidal hairspring system is the part that produces a stable vibration frequency. These two parts are organically connected through a transmission gear train and an escapement mechanism, forming the backbone of the watch movement. The vibration of the cycloidal hairspring assembly consumes a certain amount of energy, which is supplemented by the primary drive system. Large supply, large swing of the swing wheel hairspring assembly; On the contrary, if the energy supply is small, the swing angle of the swing wheel hairspring assembly is small, i.e., the swing amplitude is small. If the energy supplied is always maintained at a constant value, the swing angle of the swing wheel hairspring assembly also remains unchanged, that is, the swing amplitude remains unchanged. In fact, it is impossible for the supply of energy to remain unchanged. "Because the tight spring above the mechanical watch supplies the motive force, the torque will decrease as the spring relaxes. Of course, the energy supplied will also decrease accordingly.". In addition, this energy passes through the transmission and escapement mechanism, and the meshing characteristics of the transmission gear transmission, the operating characteristics, transmission efficiency, and escapement mechanism efficiency of the escapement mechanism are constantly changing. Therefore, the swing of the roller hairspring assembly varies at different times. If measured with a swing meter or swing recorder, the values shown are constantly fluctuating, generally taking the maximum value within a certain period of time The average of the minimum values represents the swing over the period of time.