JP7430123B2 - Watch movements and watches - Google Patents

Description

The present invention relates to a watch movement and a watch.

In a watch, the method of detecting the position of the pointer is to form a gear train so that load fluctuations occur on the rotor of a stepping motor when the pointer is at the reference position, and detect the rotational state of the rotor using induced voltage to detect the pointer. There is a technology to determine the reference position of As an example of a mechanism for generating load fluctuations in a motor that correspond to the reference position of the pointer, a method has been developed in which one tooth of a predetermined gear that rotates in conjunction with the pointer is formed into a different shape from the other teeth. . As a result, load fluctuations occur on the rotor when the one tooth meshes with another gear (for example, see Patent Document 1).

Japanese Patent Application Publication No. 2019-124681

However, for example, if the gear that causes the load fluctuation is a gear that has a relatively large reduction ratio with respect to the rotor, a plurality of hand movement steps may be required from the start to the end of the load fluctuation. In this case, the magnitude of the load detected by the induced voltage of the motor varies depending on the drive voltage of the motor, the magnitude of the drive pulse, etc., and it may be difficult to detect the reference position of the pointer.

SUMMARY OF THE INVENTION Therefore, the present invention provides a timepiece movement and a timepiece that can accurately detect the reference position of a hand.

A timepiece movement of the present invention includes a stepping motor having a rotor that rotates a pointer, and a gear train group having a gear that rotates based on the rotation of the rotor, the gear train group including a first gear, a second gear; and a first reference load section that is arranged to mesh with the first gear and that varies the load that the rotor receives when meshing with the first gear; a third gear that rotates at a reduction ratio; and a second reference load section that is arranged to mesh with the second gear and that varies the load that the rotor receives when meshing with the second gear; On the other hand, the fourth gear rotates at a second reduction ratio smaller than the first reduction ratio.

According to the present invention, the fourth gear having the second reference load portion rotates more than the third gear having the first reference load portion each time the rotor rotates one step. Therefore, the frequency at which the second reference load section and the second gear engage is higher than the frequency at which the first reference load section and the first gear engage. As a result, the second reference load section generates load fluctuations that the rotor receives more frequently than the first reference load section.
Here, because the first reduction ratio is relatively large, the first reference load section may mesh with the first gear over multiple rotation steps of the rotor. In this case, since fluctuations in the load applied to the rotor due to the first reference load section occur over multiple rotation steps of the rotor, the load fluctuation due to the first reference load section alone cannot cause the pointer to rotate in synchronization with the third gear. It may be difficult to determine the reference position.
Therefore, by combining the low-frequency load fluctuations caused by the first reference load section with the high-frequency load fluctuations caused by the second reference load section, it becomes possible to accurately determine the reference position of the pointer.
Therefore, the reference position of the pointer can be detected with high accuracy.

In the above-mentioned timepiece movement, the gear train group has a wheel to which the pointer is attached and rotates with respect to the rotor at a third reduction ratio, and the first reduction ratio is the third reduction ratio. It may be a multiple of the ratio.

According to the present invention, the pointer can be rotated once every time the third gear is rotated an integral number of revolutions. Therefore, the pointer can be configured to be positioned at the same position every time the first reference load section meshes with the first gear. Therefore, it is possible to accurately determine the reference position of the pointer.

In the above-described timepiece movement, the first reduction ratio may be a multiple of the second reduction ratio.

According to the present invention, the third gear can be rotated once every time the fourth gear is rotated by an integral number of revolutions. Therefore, the timing at which load fluctuation occurs by the second reference load section can be fixedly set relative to the timing at which load fluctuation occurs from the first reference load section. Therefore, the reference position of the pointer can be easily determined by the combination of the load variation caused by the first reference load section and the load variation caused by the second reference load section.

In the above-mentioned timepiece movement, the second reference load section is provided on one tooth of the fourth gear, and the number of steps of the stepping motor required to rotate the fourth gear once is determined by the number of steps of the stepping motor required to rotate the fourth gear once. may be equal to the number of teeth.

According to the present invention, the period during which the second reference load section meshes with the second gear and changes the load applied to the rotor corresponds to approximately one step of the stepping motor. Thereby, the second reference load section generates a load fluctuation for a period corresponding to approximately one step of the stepping motor while the fourth gear rotates once. Therefore, it becomes possible to determine the reference position of the pointer more accurately. Further, it is possible to improve the degree of freedom in the wheel train configuration.

In the above-mentioned timepiece movement, the gear train group has a gear train that transmits the rotation of the rotor to at least one of the pointer and a display wheel that displays information, and the gear train group includes the third gear train group. The gear may include a gear and the fourth gear.

According to the present invention, a gear that transmits the rotation of the rotor to at least one of the pointer and the display wheel can be used as the third gear and the fourth gear. Therefore, it is possible to form a timepiece movement that provides the above-mentioned effects without increasing the number of gears.

In the above-mentioned timepiece movement, the gear train group has a gear train that transmits the rotation of the rotor to at least one of the pointer and a display wheel that displays information, and the gear train group includes the third gear and the fourth gear. At least one of the gears may be provided separately from the gears included in the wheel train.

According to the present invention, since at least one of the third gear and the fourth gear is provided in addition to the gear that transmits the rotation of the rotor to at least one of the pointer and the display wheel, the conventional wheel train configuration can be changed. A timepiece movement that exhibits the above-mentioned effects can be formed without modification.

In the above-described timepiece movement, the first reference load section may contact the first gear and be elastically deformed, and the second reference load section may contact the second gear and be elastically deformed.

According to the present invention, the first reference load portion contacts the first gear and is elastically deformed, thereby causing energy loss in the wheel train group due to the elastic deformation. Furthermore, the second reference load portion contacts the second gear and is elastically deformed, causing energy loss in the wheel train group due to the elastic deformation. Energy loss in the wheel train group increases the load on the rotor. Therefore, it is possible to form a first reference load section and a second reference load section that vary the load that the rotor receives.

The timepiece of the present invention is characterized by comprising the above-described timepiece movement.

According to the present invention, it is possible to provide a timepiece that allows the position of the hands to be accurately determined.

According to the present invention, it is possible to provide a timepiece movement and a timepiece that can accurately detect the reference position of a hand.

FIG. 1 is an external view of a timepiece showing a first embodiment. FIG. 3 is a plan view of the front side of the movement of the first embodiment. FIG. 3 is a sectional view of the movement of the first embodiment. FIG. 3 is a plan view of the back side of the movement of the first embodiment. FIG. 2 is a plan view showing a part of the movement of the first embodiment, and is a view of the first gear train group viewed from the front side. FIG. 3 is a perspective view of the second hour intermediate wheel according to the first embodiment. It is a top view which shows a part of movement of 2nd Embodiment, Comprising: It is a figure which looked at the 1st gear train group from the front side. It is a top view which shows a part of movement of 3rd Embodiment, Comprising: It is a figure which looked at the 1st gear train group from the front side.

Embodiments of the present invention will be described below based on the drawings. In the following description, components having the same or similar functions are given the same reference numerals. Further, redundant explanations of these configurations may be omitted.

[First embodiment]
Generally, the mechanical body that includes the driving parts of a timepiece is called a "movement." When a dial and hands are attached to this movement and the watch is placed inside a watch case, the finished product is called a ``complete'' watch. Of both sides of the base plate that constitutes the base plate of the watch, the side with the glass of the watch case (that is, the side with the dial) is referred to as the "back side" of the movement. Furthermore, of both sides of the main plate, the side on which the case back of the watch case is located (that is, the side opposite to the dial plate) is referred to as the "front side" of the movement.

FIG. 1 is an external view of a timepiece showing a first embodiment.
As shown in FIG. 1, the complete watch 1 of this embodiment includes a movement 4 (watch movement), a dial 5 having a scale, and a watch case 2 consisting of a case back cover and a glass 3 (not shown). It includes an hour hand 6 (hand), a minute hand 7, a second hand 8 (hand), and a 24-hour hand 9. A date window 5a is opened in the dial 5 to clearly indicate a date 46a displayed on a date dial 46 (display wheel), which will be described later. This allows the watch 1 to check the date in addition to the time.

FIG. 2 is a plan view of the front side of the movement of the first embodiment. FIG. 3 is a sectional view of the movement of the first embodiment.
As shown in FIGS. 2 and 3, the movement 4 includes a main plate 11, a gear train bridge 12, a date dial holder 13, a second bridge 14, a first motor 20A, a second motor 20B, and a first It mainly includes a wheel train group 30 and a second wheel train group 50.

As shown in FIG. 3, the main plate 11 constitutes a base plate of the movement 4. As shown in FIG. The gear train bridge 12 is arranged on the front side of the main plate 11. The date indicator holder 13 is arranged on the back side of the main plate 11. The second bridge 14 is arranged between the main plate 11 and the gear train bridge 12.

As shown in FIG. 2, the first motor 20A and the second motor 20B are stepping motors having a stator 21 and a rotor 22, respectively. The number of magnetic poles of the rotor 22 is two. Each of the first motor 20A and the second motor 20B rotates the rotor 22 by 180 degrees in one step. The first motor 20A generates power to rotate the hour hand 6, the 24-hour hand 9, and the date dial 46 (see FIG. 1). The first motor 20A rotates the rotor 22 one step every minute. The second motor 20B generates power to rotate the minute hand 7 and the second hand 8 (see FIG. 1). The second motor 20B rotates the rotor 22 two steps every second. A pinion is formed on the rotor 22 of each of the first motor 20A and the second motor 20B.

FIG. 4 is a plan view of the back side of the movement of the first embodiment. FIG. 5 is a plan view showing a part of the movement of the first embodiment, and is a view of the first gear train group viewed from the front side.
As shown in FIGS. 4 and 5, the first wheel train group 30 includes gears that rotate based on the rotation of the rotor 22 of the first motor 20A. The first wheel train group 30 includes a hour train 31 that transmits the rotation of the rotor 22 of the first motor 20A to the hour hand 6, and a calendar that transmits the rotation of the rotor 22 of the first motor 20A to the 24-hour hand 9 and the date wheel 46. A wheel train 41 is provided.

As shown in FIGS. 3 and 5, the hour wheel train 31 includes a first hour intermediate wheel 32, a second hour intermediate wheel 33, a third hour intermediate wheel 34, and an hour wheel 35.
The first hour intermediate wheel 32 is rotatably supported by the main plate 11 and the train wheel bridge 12. The first hour intermediate gear 32 includes a first hour intermediate gear 32a and a first hour intermediate pinion 32b. The first hour intermediate gear 32a meshes with the pinion of the rotor 22 of the first motor 20A between the base plate 11 and the gear train bridge 12. The first intermediate wheel 32 rotates at a reduction ratio of 6 with respect to the rotor 22. That is, the first hour intermediate wheel 32 rotates once every six rotations of the rotor 22 of the first motor 20A.

The second hour intermediate wheel 33 is rotatably supported by the main plate 11 and the train wheel bridge 12. The second hour intermediate wheel 33 includes a second hour intermediate gear 33a and a second hour intermediate pinion 33b. The second hour intermediate gear 33a meshes with the first hour intermediate pinion 32b of the first hour intermediate wheel 32 between the base plate 11 and the train wheel bridge 12. The second hour intermediate wheel 33 is a driven gear with respect to the first hour intermediate wheel 32. The second hour intermediate wheel 33 rotates at a reduction ratio of 7.5 with respect to the first hour intermediate wheel 32. That is, the second hour intermediate wheel 33 rotates at a reduction ratio of 45 with respect to the rotor 22 of the first motor 20A.

The third hour intermediate wheel 34 is rotatably supported by the main plate 11 between the main plate 11 and the date wheel holder 13. The third hour intermediate wheel 34 includes a third hour intermediate gear 34a and a third hour intermediate pinion 34b. The third hour intermediate gear 34a meshes with the second hour intermediate pinion 33b of the second hour intermediate wheel 33 on the back side of the main plate 11. The third hour intermediate wheel 34 is a driven gear with respect to the second hour intermediate wheel 33. The third hour intermediate wheel 34 rotates at a reduction ratio of eight relative to the second hour intermediate wheel 33. That is, the third hour intermediate wheel 34 rotates at a reduction ratio of 360 with respect to the rotor 22 of the first motor 20A.

The hour wheel 35 is rotatably fitted onto the center pipe 15 on the back side of the main plate 11. The center pipe 15 is held by the base plate 11. The center pipe 15 projects from the base plate 11 to the back side. The hour wheel 35 is held down by the date wheel holder 13 from the back side via the dial washer. The end of the back side of the hour wheel 35 protrudes from the date wheel holder 13 to the back side. An hour hand 6 (see FIG. 1) is attached to the end of the back side of the hour wheel 35. The hour wheel 35 has a cylindrical gear 35a. The barrel gear 35a meshes with the third hour intermediate gear 34a of the third hour intermediate wheel 34. The hour wheel 35 is a driven gear for the third hour intermediate wheel 34. The hour wheel 35 rotates at a reduction ratio of 1 with respect to the third hour intermediate wheel 34. That is, the hour wheel 35 rotates at a reduction ratio of 360 with respect to the rotor 22 of the first motor 20A.

As shown in FIG. 5, the calendar wheel train 41 includes the above-mentioned first hour intermediate wheel 32, second hour intermediate wheel 33, third hour intermediate wheel 34, 24 hour wheel 42, and date intermediate wheel 43. Equipped with
The 24-hour wheel 42 is rotatably supported by the main plate 11 between the main plate 11 and the date wheel holder 13. The shaft portion of the 24-hour wheel 42 protrudes from the date wheel holder 13 to the back side. A 24-hour hand 9 (see FIG. 1) is attached to the back end of the shaft. The 24-hour wheel 42 has a 24-hour gear 42a. The 24-hour gear 42a meshes with the third hour intermediate pinion 34b of the third hour intermediate wheel 34 on the back side of the main plate 11. The 24 hour wheel 42 is a driven gear for the third hour intermediate wheel 34. The 24 hour wheel 42 rotates at a reduction ratio of 2 relative to the third hour intermediate wheel 34. That is, the 24-hour wheel 42 rotates at a reduction ratio of 720 with respect to the rotor 22 of the first motor 20A.

The intermediate date wheel 43 is rotatably supported by the main plate 11 between the main plate 11 and the date indicator holder 13. The rotation center of the date intermediate wheel 43 is provided at a position shifted by an angle of less than 180 degrees from the rotation center of the third hour intermediate wheel 34 around the rotation center of the 24-hour wheel 42. In other words, the rotation center of the date intermediate wheel 43 is located off the straight line passing through the rotation center of the 24-hour wheel 42 and the rotation center of the third hour intermediate wheel 34 in plan view. The date intermediate gear 43 includes a date intermediate gear 43a and a disc wheel 43b. The date intermediate gear 43a meshes with the 24-hour gear 42a on the back side of the main plate 11. The date intermediate wheel 43 is a driven wheel for the 24-hour wheel 42. The date intermediate wheel 43 rotates at a reduction ratio of 1 with respect to the 24-hour wheel 42. That is, the date intermediate wheel 43 rotates at a reduction ratio of 720 with respect to the rotor 22 of the first motor 20A. The disc wheel 43b overlaps the date intermediate gear 43a. The disc wheel 43b includes a feed dog 43c. The feed dog 43c projects radially outward from the outer peripheral surface of the disc wheel 43b.

The date wheel 44 is rotatably supported by the main plate 11 between the main plate 11 and the date indicator holder 13. The date wheel 44 has a date wheel 44a. The date gear 44a is formed to be able to mesh with the feed tooth 43c of the intermediate date gear 43. The date wheel 44 rotates when the feed tooth 43c of the intermediate date wheel 43 enters the rotation locus of the date wheel 44a and engages with it. Therefore, the date wheel 44 is intermittently rotated by the rotation of the intermediate date wheel 43. The date wheel 44 rotates the date wheel 46.

The date dial 46 is a ring-shaped member rotatably attached to the main plate 11. The date dial 46 is held down from the back side by the date dial holder 13 (see FIG. 4). On the back side of the date indicator 46, date information 46a (see FIG. 1) is displayed along the circumferential direction. The date dial 46 displays date information by exposing the date character 46a through the date window 5a of the dial plate 5. A plurality of internal teeth 46b are formed on the inner peripheral edge of the date dial 46 over the entire circumference. The internal teeth 46b mesh with the date gear 44a. The date wheel 46 rotates in conjunction with the rotation of the date wheel 44. Therefore, the date wheel 46 is intermittently rotated by the rotation of the intermediate date wheel 43. The position of the date dial 46 in the rotational direction is regulated by a jumper 47. The jumper 47 restricts the rotation of the date dial 46 by engaging the claw at the tip with the internal teeth 46b of the date dial 46.

As shown in FIGS. 2 and 3, the second wheel train group 50 includes gears that rotate based on the rotation of the rotor 22 of the second motor 20B. The second wheel train group 50 includes a front wheel train 51 that transmits the rotation of the rotor 22 of the second motor 20B to the second hand 8 and the minute hand 7 (both shown in FIG. 1). The front wheel train 51 includes a fourth intermediate wheel 52, a fourth wheel & pinion 53, a third wheel & pinion 54, and a center wheel & pinion 55.

The fourth intermediate wheel 52 is rotatably supported by the main plate 11. The fourth intermediate wheel 52 includes a fourth intermediate gear 52a and a fourth intermediate pinion 52b. The fourth intermediate gear 52a meshes with the pinion of the rotor 22 of the second motor 20B between the base plate 11 and the gear train bridge 12. The fourth intermediate wheel 52 rotates at a reduction ratio of 6 with respect to the rotor 22 of the second motor 20B.

The fourth wheel & pinion 53 is rotatably supported by the train wheel bridge 12. The fourth wheel & pinion 53 includes a fourth stem 53a, a fourth gear 53b assembled to the fourth stem 53a, and a fourth pinion 53c formed on the fourth stem 53a. The fourth stem 53a is inserted inside the second stem 55a, which will be described later. The fourth stem 53a projects further to the back side than the second stem 55a. The second hand 8 (see FIG. 1) is attached to the back end of the fourth stem 53a. The fourth gear 53b meshes with the fourth intermediate pinion 52b. The fourth wheel & pinion 53 is a driven gear for the fourth intermediate wheel 52. The fourth wheel & pinion 53 rotates at a reduction ratio of 10 with respect to the fourth intermediate wheel 52. That is, the fourth wheel & pinion 53 rotates at a reduction ratio of 60 with respect to the rotor 22 of the second motor 20B.

The third wheel & pinion 54 is rotatably supported by the main plate 11 and the gear train bridge 12. The third wheel 54 includes a third gear 54a and a third pinion (not shown). The third gear 54a meshes with the fourth pinion 53c. The third wheel & pinion 54 is a driven gear for the fourth wheel & pinion 53. The third wheel & pinion 54 rotates at a reduction ratio of 20 relative to the fourth wheel & pinion 53. That is, the third wheel & pinion 54 rotates at a reduction ratio of 400 with respect to the rotor 22 of the second motor 20B.

The center wheel 55 is rotatably supported by the center bridge 14 and the center pipe 15. The center wheel 55 includes a second stem 55a and a second gear 55b assembled to the second stem 55a. The second stem 55a is formed into a cylindrical shape and inserted inside the center pipe 15. The second stem 55a projects further to the back side than the hour wheel 35. A minute hand 7 (see FIG. 1) is attached to the back end of the second stem 55a. The second gear 55b meshes with the third pinion. The second wheel & pinion 55 is a driven gear relative to the third wheel & pinion 54. The second wheel & pinion 55 rotates at a reduction ratio of 9 with respect to the third wheel & pinion 54. That is, the center wheel & pinion 55 rotates at a reduction ratio of 3600 with respect to the rotor 22 of the second motor 20B.

As shown in FIG. 5, two of the plurality of gears included in the first wheel train group 30 are provided with a reference load section 60. The 24-hour gear 42a has a first reference load section 60A. The second hour intermediate gear 33a has a second reference load section 60B. Note that since the first reference load section 60A and the second reference load section 60B are formed in the same manner, the second reference load section 60B will be described below, and a detailed explanation regarding the configuration of the first reference load section 60A will be given below. is omitted.

FIG. 6 is a perspective view of the second hour intermediate wheel according to the first embodiment.
As shown in FIG. 6, the second hour intermediate gear 33a has a plurality of teeth 61 and an elastic portion 65. The plurality of teeth 61 include standard teeth 62 and elastic teeth 63 as a second reference load section 60B. The standard teeth 62 are all teeth among the plurality of teeth 61 except for the elastic teeth 63. The standard teeth 62 are teeth of a general gear, and are teeth formed in a circular arc tooth profile, an involute tooth profile, a cycloid tooth profile, or the like. The elastic tooth 63 is one of the teeth 61 of the second hour intermediate gear 33a. The elastic teeth 63 are formed to be elastically displaceable.

The elastic portion 65 is a cantilever beam that has elastic teeth 63 at its tip and is formed to be flexibly deformable. The elastic portion 65 is a portion between a first slit 67 and a second slit 68 formed in the second hour intermediate gear 33a. The first slit 67 extends radially inward from one tooth groove adjacent to the elastic tooth 63 and then extends toward one side in the circumferential direction. The second slit 68 extends from the other tooth groove adjacent to the elastic tooth 63 along the first slit 67 . Thereby, the elastic portion 65 extends with a substantially constant width and is formed to be elastically deformable so as to displace the elastic tooth 63 at the tip in the radial direction.

The function of the reference load section 60 will be explained.
As shown in FIGS. 5 and 6, among the plurality of teeth 61 of the second hour intermediate gear 33a, when the tooth that engages with the first hour intermediate pinion 32b is changed from the standard tooth 62 to the elastic tooth 63, the elastic tooth 63 is in contact with the teeth of the first intermediate pinion 32b. Thereafter, when the first intermediate pinion 32b further rotates, the elastic teeth 63 are displaced inward in the radial direction while being accompanied by elastic deformation of the elastic portion 65. As a result, energy loss occurs in the first wheel train group 30 due to the elastic deformation of the elastic portion 65. Therefore, when the elastic teeth 63 mesh with the first intermediate pinion 32b, the load applied to the rotor 22 of the first motor 20A is increased more than when the standard teeth 62 mesh with the first intermediate pinion 32b. In other words, the second reference load section 60B changes the load applied to the rotor 22 of the first motor 20A once every time the second intermediate wheel 33 rotates once.

Since the first reference load section 60A is provided on the 24-hour gear 42a, the load that the rotor 22 of the first motor 20A receives when the teeth of the third hour intermediate pinion 34b come into contact with the first reference load section 60A. increase. In other words, the first reference load section 60A changes the load applied to the rotor 22 of the first motor 20A once every time the 24-hour wheel 42 rotates once. Furthermore, since the 24-hour wheel 42 rotates once every two rotations of the hour wheel 35, the first reference load section 60A absorbs the load applied to the rotor 22 of the first motor 20A once every two rotations of the hour hand 6. Vary.

The second hour intermediate wheel 33 rotates with a reduction ratio smaller than the reduction ratio of the 24-hour wheel 42 with respect to the rotor 22 of the first motor 20A. Therefore, the second reference load section 60B changes the load applied to the rotor 22 of the first motor 20A more frequently than the first reference load section 60A. In particular, the reduction ratio of the 24-hour wheel 42 is an integral multiple of the reduction ratio of the second hour intermediate wheel 33. Therefore, the second reference load section 60B changes the load applied to the rotor 22 of the first motor 20A at a frequency that is an integral multiple of the first reference load section 60A.

The 24-hour gear 42a meshes with the date intermediate gear 43a in addition to the third hour intermediate pinion 34b. The 24-hour gear 42a is a driven gear for the third hour intermediate pinion 34b, while it is a driving gear for the date intermediate gear 43a. Therefore, the load fluctuation when the teeth of the date intermediate gear 43a contact the first reference load section 60A is greater than the load fluctuation when the teeth of the third hour intermediate pinion 34b contact the first reference load section 60A. Small enough. Therefore, the load fluctuation due to the meshing with the third hour intermediate pinion 34b can be distinguished from the load fluctuation due to the meshing with the date intermediate gear 43a.

Furthermore, the rotation center of the date intermediate wheel 43 is located at a position that is off the straight line passing through the rotation center of the 24-hour wheel 42 and the rotation center of the third hour intermediate wheel 34 in plan view. Therefore, based on the relationship between the timing at which load fluctuations occur due to the meshing with the third hour intermediate pinion 34b and the timing at which load fluctuations occur due to the meshing with the date intermediate gear 43a, Load fluctuations due to meshing can be distinguished from load fluctuations due to meshing with the date intermediate gear 43a.

Note that, as shown in FIG. 2, also in the second wheel train group 50, reference load sections 60 are provided on two gears (only one reference load section 60 is shown in FIG. 2). In this embodiment, a reference load section 60 is provided for each of the second gear 55b and the fourth gear 53b. The fourth wheel & pinion 53 rotates with a reduction ratio smaller than that of the second wheel & pinion 55 with respect to the rotor 22 of the second motor 20B. Therefore, the reference load section 60 provided on the center wheel & pinion 53 changes the load applied to the rotor 22 of the second motor 20B more frequently than the reference load section 60 provided on the center wheel & pinion 55.

As described above, in the present embodiment, the first gear train group 30 of the movement 4 is arranged to mesh with the third hour intermediate pinion 34b, and when meshing with the third hour intermediate pinion 34b, the first motor 20A It has a first reference load section 60A that varies the load received by the rotor 22 of the first motor 20A, and meshes with the 24-hour gear 42a that rotates at a reduction ratio of 720 with respect to the rotor 22 of the first motor 20A and the first hour intermediate pinion 32b. It has a second reference load section 60B that varies the load received by the rotor 22 of the first motor 20A when meshing with the first intermediate pinion 32b, and has a second reference load section 60B that varies the load received by the rotor 22 of the first motor 20A. A second hour intermediate gear 33a that rotates at a ratio of 45 is provided.

According to this configuration, the second hour intermediate gear 33a having the second reference load section 60B is faster than the 24 hour gear 42a having the first reference load section 60A every time the rotor 22 of the first motor 20A rotates one step. It rotates greatly. Therefore, the frequency at which the second reference load portion 60B and the first hour intermediate pinion 32b engage is higher than the frequency at which the first reference load portion 60A and the third hour intermediate pinion 34b engage. Thereby, the second reference load section 60B generates load fluctuations that the rotor 22 of the first motor 20A receives more frequently than the first reference load section 60A. Here, because the reduction ratio of the 24-hour gear 42a is relatively large, the first reference load section 60A may mesh with the third hour intermediate pinion 34b over a plurality of rotation steps of the rotor 22 of the first motor 20A. In this case, since the variation in the load applied to the rotor 22 of the first motor 20A by the first reference load section 60A occurs over multiple rotation steps of the rotor 22, the load variation due to the first reference load section 60A alone cannot It may be difficult to determine the reference position of the hour hand 6, which rotates in synchronization with the 3 o'clock middle pinion 34b. Therefore, by combining the low-frequency load fluctuations caused by the first reference load section 60A with the high-frequency load fluctuations caused by the second reference load section 60B, it becomes possible to accurately determine the reference position of the hour hand 6. Therefore, the reference position of the hour hand 6 can be detected with high accuracy.

The first wheel train group 30 also includes an hour wheel 35 to which the hour hand 6 is attached and rotates at a reduction ratio of 360 with respect to the rotor 22 of the first motor 20A. The reduction ratio of the 24-hour gear 42a is a multiple of the reduction ratio of the hour wheel 35. According to this configuration, the hour hand 6 can be rotated once every time the 24-hour gear 42a is rotated an integral number of revolutions. Therefore, the hour hand 6 can be configured to be positioned at the same position every time the first reference load section 60A engages with the third hour intermediate pinion 34b. Therefore, it becomes possible to accurately determine the reference position of the hour hand 6.

Further, the reduction ratio of the 24-hour gear 42a is a multiple of the reduction ratio of the second hour intermediate gear 33a. According to this configuration, the 24-hour gear 42a can be rotated once every time the second hour intermediate gear 33a is rotated an integral number of revolutions. Therefore, the timing at which the load fluctuation occurs by the second reference load section 60B can be fixedly set relative to the timing at which the load fluctuation occurs at the first reference load section 60A. Therefore, the reference position of the hour hand 6 can be easily determined by the combination of the load variation caused by the first reference load section 60A and the load variation caused by the second reference load section 60B.

The first wheel train group 30 also includes a hour train 31 that transmits the rotation of the rotor 22 of the first motor 20A to the hour hand 6, and a time wheel train 31 that transmits the rotation of the rotor 22 of the first motor 20A to the 24-hour hand 9 and the date dial 46. It has a calendar wheel train 41. The time wheel train 31 and the calendar wheel train 41 include a 24-hour gear 42a and a second intermediate hour gear 33a. According to this configuration, the gear that transmits the rotation of the rotor 22 of the first motor 20A to at least one of the hour hand 6, the 24-hour hand 9, and the date dial 46 is connected to the first reference load section 60A and the second reference load section. It can be used as a gear with 60B. Therefore, the movement 4 that achieves the above-mentioned effects can be formed without increasing the number of gears.

Further, the first reference load portion 60A contacts the third intermediate pinion 34b and is elastically deformed. The second reference load portion 60B contacts the first intermediate pinion 32b and is elastically deformed. According to this configuration, when the first reference load portion 60A contacts the third intermediate pinion 34b and is elastically deformed, energy loss occurs in the first wheel train group 30 due to the elastic deformation. Further, the second reference load portion 60B contacts the first intermediate pinion 32b and is elastically deformed, thereby causing energy loss in the first wheel train group 30 due to the elastic deformation. The energy loss that occurs in the first wheel train group 30 increases the load that the rotor 22 of the first motor 20A receives. Therefore, it is possible to form a first reference load section 60A and a second reference load section 60B that vary the load that the rotor 22 of the first motor 20A receives.

Since the timepiece 1 of this embodiment includes the movement 4 described above, the timepiece 1 can accurately determine the position of the hour hand 6.

Note that in the above explanation, the effects of the first reference load section 60A and the second reference load section 60B in the first wheel train group 30 have been explained, but the same applies to the pair of reference load sections 60 in the second wheel train group 50. It has similar effects. That is, since the fourth gear 53b and the second gear 55b each have a reference load section 60, the reference positions of the minute hand 7 and second hand 8 are accurately determined based on fluctuations in the load applied to the rotor 22 of the second motor 20B. becomes possible.

[Second embodiment]
FIG. 7 is a plan view showing a part of the movement of the second embodiment, and is a view of the first gear train group viewed from the front side.
In the first embodiment shown in FIG. 5, both the first reference load section 60A and the second reference load section 60B are provided on at least one of the gears of the time wheel train 31 and the calendar wheel train 41. On the other hand, the second embodiment shown in FIG. 7 differs from the first embodiment in that the second reference load section 60B is provided on a gear different from the time wheel train 31 and the calendar wheel train 41. Note that the configuration other than that described below is the same as that of the first embodiment.

As shown in FIG. 7, the first wheel train group 30A of the present embodiment has a dedicated gear 36 added to the first wheel train group 30 of the first embodiment, and the second reference load section 60B is It has a configuration in which the dedicated gear 36 is provided instead of the time intermediate gear 33a. The dedicated gear 36 meshes only with the first hour intermediate pinion 32b of the first hour intermediate wheel 32. The dedicated gear 36 is a driven gear for the first intermediate wheel 32 . Of the torque transmission paths of the rotor 22 of the first motor 20A in the first wheel train group 30A, the dedicated gear 36 is arranged on a path that does not transmit torque to any of the hour hand 6, 24-hour hand 9, and date dial 46. There is. The dedicated gear 36 rotates at a reduction ratio of 7.5 with respect to the first intermediate wheel 32. That is, the dedicated gear 36 rotates at a reduction ratio of 45 with respect to the rotor 22 of the first motor 20A.

As mentioned above, the dedicated gear 36 has the second reference load section 60B. Therefore, like the second hour intermediate gear 33a of the first embodiment, the second reference load section 60B changes the load applied to the rotor 22 of the first motor 20A once every rotation of the dedicated gear 36. let The dedicated gear 36 rotates with a reduction ratio smaller than the reduction ratio of the 24-hour wheel 42 with respect to the rotor 22 of the first motor 20A. Therefore, the second reference load section 60B changes the load applied to the rotor 22 of the first motor 20A more frequently than the first reference load section 60A. In particular, the reduction ratio of the 24-hour wheel 42 is an integral multiple of the reduction ratio of the dedicated gear 36. Therefore, the second reference load section 60B changes the load applied to the rotor 22 of the first motor 20A at a frequency that is an integral multiple of the first reference load section 60A.

As explained above, in this embodiment, the first gear train group 30A of the movement 4 includes the 24-hour gear 42a having the first reference load section 60A, the dedicated gear 36 having the second reference load section 60B, Therefore, the same effects as in the first embodiment can be achieved.

Further, the dedicated gear 36 is provided separately from the gears included in the time wheel train 31 and the calendar wheel train 41. According to this configuration, the dedicated gear 36 is provided separately from the gear that transmits the rotation of the rotor 22 of the first motor 20A to at least one of the hour hand 6, 24-hour hand 9, and date dial 46. The movement 4 that exhibits the above-mentioned effects can be formed without changing the configuration.

[Third embodiment]
FIG. 8 is a plan view showing a part of the movement of the third embodiment, and is a view of the first gear train group viewed from the front side.
The third embodiment shown in FIG. 8 differs from the first embodiment in that the second intermediate wheel 33 rotates at a reduction ratio of 36 with respect to the rotor 22 of the first motor 20A. Note that the configuration other than that described below is the same as that of the first embodiment.

As shown in FIG. 8, the first wheel train group 30B of the present embodiment has a reduction ratio of the first motor 20A of the second hour intermediate wheel 33 to the rotor 22, compared to the first wheel train group 30 of the first embodiment. is being changed. The number of teeth of the second hour intermediate gear 33a of the second hour intermediate wheel 33 is 72. The second hour intermediate wheel 33 rotates at a reduction ratio of 6 relative to the first hour intermediate wheel 32. That is, the second hour intermediate wheel 33 rotates at a reduction ratio of 36 with respect to the rotor 22 of the first motor 20A. The third hour intermediate wheel 34 rotates at a reduction ratio of 10 relative to the second hour intermediate wheel 33. That is, the third hour intermediate wheel 34 rotates at a reduction ratio of 360 with respect to the rotor 22 of the first motor 20A.

In this embodiment, the number of magnetic poles of the rotor 22 of the first motor 20A is two. Therefore, the number of steps of the first motor 20A required to rotate the second hour intermediate gear 33a provided with the second reference load portion 60B once is 72, which is equal to the number of teeth of the second hour intermediate gear 33a.

According to this embodiment, the period during which the second reference load section 60B meshes with the first intermediate pinion 32b and changes the load received by the rotor 22 corresponds to approximately one step of the first motor 20A. Thereby, the second reference load section 60B generates a load fluctuation for a period corresponding to approximately one step of the first motor 20A while the second hour intermediate gear 33a rotates once. Therefore, compared to a configuration in which the reference load section generates load fluctuations over a period corresponding to a plurality of steps of the first motor 20A, it becomes possible to determine the reference position of the hour hand 6 more accurately. Further, it is possible to improve the degree of freedom in the wheel train configuration.

Note that the present invention is not limited to the above-described embodiments described with reference to the drawings, and various modifications can be made within the technical scope thereof.
For example, in the above embodiment, the reference load portion 60 is provided in the second hour intermediate gear 33a and the 24 hour gear 42a in the first wheel train group 30, but the reference load portion may be provided in other gears. good. However, it is desirable that the reference load section be provided on the driven gear of the pair of gears that mesh with each other. Thereby, the load that the rotor 22 receives can be increased compared to a configuration in which the reference load section is provided on the drive-side gear.

Further, in the above embodiment, the first reference load section 60A is provided on a gear included in the calendar wheel train 41, but the first reference load section 60A is provided on a gear not included in the time wheel train 31 and the calendar wheel train 41. may be provided.

Further, in the above embodiment, the reference load section 60 is formed by making one tooth of a gear elastically displaceable, but the present invention is not limited to this. For example, the reference load portion may be formed by making one tooth of a gear a different shape from other teeth.

Further, in the above embodiment, the date indicator 46 has been described as an example of the display wheel for displaying information, but the display wheel is not limited to the date indicator 46. For example, a day wheel that displays the day of the week as information may be used as the display wheel.

In addition, the components in the embodiments described above may be replaced with known components as appropriate without departing from the spirit of the present invention, and the embodiments described above may be combined as appropriate.

1...Clock 4...Movement (watch movement) 6...Hour hand (pointer) 8...Second hand (pointer) 20A...First motor (stepping motor) 20B...Second motor (stepping motor) 22...Rotor 30, 30A, 30B... 1st gear train group (wheel train group) 31... Hour gear train (wheel train) 32b... 1st hour intermediate gear (1st gear) 33a... 2nd hour intermediate gear (4th gear) 34b... 3rd hour intermediate gear (Second gear) 35... Hour wheel (wheel) 41... Calendar gear train 42a... 24 hour gear (third gear) 46... Date wheel (display wheel) 50... Second wheel train group (wheel train group) 60A... No. 1 reference load section 60B...2nd reference load section

Claims (8)

a stepping motor having a rotor that rotates a pointer;
a gear train group having gears that rotate based on rotation of the rotor;
Equipped with
The gear train group is
A first gear,
a second gear;
The rotor has a first reference load section that is arranged to mesh with the first gear and that varies the load that the rotor receives when it meshes with the first gear, and rotates at a first reduction ratio with respect to the rotor. The third gear,
a second reference load section that is disposed to mesh with the second gear and that varies the load that the rotor receives when meshing with the second gear, and has a second reference load section that is arranged to mesh with the second gear, and has a second reference load section that varies the load that the rotor receives when meshing with the second gear; a fourth gear rotating at a small second reduction ratio;
Equipped with
A watch movement characterized by: The wheel train group includes a wheel to which the pointer is attached and rotates at a third reduction ratio with respect to the rotor,
The first reduction ratio is a multiple of the third reduction ratio,
The timepiece movement according to claim 1, characterized in that: The first reduction ratio is a multiple of the second reduction ratio,
The timepiece movement according to claim 1 or 2, characterized in that: The second reference load section is provided on one tooth of the fourth gear,
The number of steps of the stepping motor required to rotate the fourth gear once is equal to the number of teeth of the fourth gear.
The timepiece movement according to any one of claims 1 to 3, characterized in that: The wheel train group has a wheel train that transmits the rotation of the rotor to at least one of the pointer and a display wheel that displays information,
The gear train includes the third gear and the fourth gear,
The timepiece movement according to any one of claims 1 to 4, characterized in that: The wheel train group has a wheel train that transmits the rotation of the rotor to at least one of the pointer and a display wheel that displays information,
At least one of the third gear and the fourth gear is provided separately from gears included in the wheel train.
The timepiece movement according to any one of claims 1 to 4, characterized in that: the first reference load section is elastically deformed in contact with the first gear;
The second reference load section is elastically deformed in contact with the second gear.
The timepiece movement according to any one of claims 1 to 6, characterized in that: A timepiece comprising the timepiece movement according to any one of claims 1 to 7.

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