CN110673457B

CN110673457B - Spiral spring, torque generating device, movement for timepiece, and timepiece

Info

Publication number: CN110673457B
Application number: CN201910573012.6A
Authority: CN
Inventors: 川内谷卓磨; 森裕一; 藤枝久; 伊东贤吾
Original assignee: Seiko Instruments Inc
Current assignee: Seiko Instruments Inc
Priority date: 2018-07-02
Filing date: 2019-06-28
Publication date: 2022-06-03
Anticipated expiration: 2039-06-28
Also published as: CH715176B1; JP6626594B1; CN110673457A; JP2020008560A; CH715176A2

Abstract

The invention provides a spiral spring, a torque generating device, a movement for a timepiece, and a timepiece, which can suppress self-contact or contact with surrounding components and generate a desired torque. The constant force spring (100) is a helical spring for a timepiece that is wound around a first rotation axis (O1) to generate a torque, and is provided with an outer end portion (101) attached to a carrier and an inner end portion (102) attached to a constant force lower stage cylinder. The outer end portion (101) is mounted to the carrier, and the inner end portion (102) is mounted to the constant force lower stage drum, and, in a pre-wind-up state in which no torque is generated, the spacing between adjacent springs in a radial direction orthogonal to the first rotation axis (O1) varies depending on the position in the circumferential direction around the first rotation axis (O1).

Description

Spiral spring, torque generating device, movement for timepiece, and timepiece

Technical Field

The invention relates to a spiral spring (eye ばね), a torque generating device, a movement for a timepiece, and a timepiece.

Background

In general, in a mechanical timepiece, if the torque (power) transmitted from a barrel wheel to an escapement fluctuates according to unwinding of a mainspring, the swing angle of a balance changes in accordance with the fluctuation of the torque, and a clock rate (how slow or fast the timepiece is) changes. In view of this, it is known to provide a constant torque mechanism in a power transmission path from the barrel wheel to the escapement in order to suppress fluctuations in torque transmitted to the escapement.

In the constant torque mechanism, a constant force spring is disposed which imparts a rotational force to the escapement-side gear train. The constant force spring is in a state of generating a constant torque by winding up or the like, and is configured to periodically supplement a loss amount of power lost by transmission of power to the escapement-side gear train by power transmitted from the barrel wheel. Various types of constant torque mechanisms have been proposed, and when, for example, periodic control is focused, the mechanisms are roughly classified into three types, namely, a cam type, a gear train type, and a planetary gear type.

The cam type constant torque mechanism includes a follower or a fork which is engaged with, for example, a cam connected to an escapement side train wheel, swings in accordance with the rotation of the cam, and periodically engages and disengages an engagement/disengagement pawl provided in the follower or the fork with an escapement wheel connected to a power source side train wheel, thereby controlling an engagement/disengagement period. Thus, the constant-force spring between the power source-side train wheel and the escapement-side train wheel can be wound up.

In the constant torque mechanism of the gear train system, the power source side gear train and the escapement side gear train are connected by a differential mechanism, and the phase difference can be controlled periodically by moving the engagement/disengagement pawl, which is disengaged from the detent wheel, into and out of the track of the detent wheel.

For example, as described in patent document 1 below, a planetary-type constant torque mechanism includes a planetary mechanism using a detent wheel as a planetary wheel, and the phase difference between a power source-side train wheel and an escaper-side train wheel can be periodically controlled by the planetary mechanism. The planetary gear revolves an engaging/disengaging pawl provided on an output wheel connected to the escapement-side gear train while rotating in a following manner.

Documents of the prior art

Patent document

Patent document 1: swiss patent application publication No. 707938.

Disclosure of Invention

Problems to be solved by the invention

However, when the coil spring is used as the constant force spring, there is a possibility that the torque generated by the deformation of the coil spring accompanying the winding may fluctuate. For example, when a spiral spring is wound and torque is generated, in a portion on the opposite side of the outer end portion of the spiral spring with respect to the rotation center at the time of winding, the interval between adjacent springs may be narrowed, and contact between the springs may be generated. Further, when the coil spring is unwound to generate a torque, in a portion on the opposite side of the rotation center at the time of unwinding from the outer end portion of the coil spring, the interval between adjacent springs is increased, the outer diameter of the coil spring is increased, and the coil spring may contact with a surrounding member. If contact is made with the coil spring, the coil spring sometimes fails to generate a desired torque due to friction in the contact portion.

The present invention provides a spiral spring, a torque generating device, a movement for a timepiece, and a timepiece, which are capable of generating a desired torque while suppressing self-contact or contact with surrounding components.

Means for solving the problems

The coil spring for a timepiece according to the present invention is a coil spring wound around an axis to generate a torque, and includes an outer end portion attached to a first member and an inner end portion attached to a second member, the outer end portion being attached to the first member and the inner end portion being attached to the second member, and a pitch between springs adjacent in a radial direction orthogonal to the axis changes depending on a position in a circumferential direction around the axis in a state before winding where no torque is generated.

According to the present invention, the shape of the coiled spring can be arbitrarily adjusted by appropriately adjusting and changing the pitch between the adjacent springs according to the position in the circumferential direction. Therefore, it is possible to suppress the case where the springs contact each other due to the narrowing of the pitch between the springs caused by the winding deformation of the coil spring, the case where the outermost peripheral portion of the coil spring contacts the surrounding member due to the widening of the pitch between the springs, and the like. Thus, the reduction of the torque generated by the coil spring can be suppressed by the frictional force caused by the contact of the coil spring in the wound-up state. Therefore, the coil spring can suppress self-contact or contact to surrounding components and generate a desired torque.

In the above-described spiral spring, the following configuration is desirable: the pitch of a first half straight line extending from the axis to the outer end portion is narrower than the pitch of a second half straight line extending from the axis to a side opposite to the first half straight line in the pre-wind-up state as viewed in the axial direction of the axis.

According to the present invention, if the spiral spring is wound up from the pre-wind-up state, the space between the springs is deformed in a narrowed manner in the portion on the opposite side of the outer end portion across the axis. Therefore, in the pre-wind-up state, the pitch between the springs on the first half straight line extending from the axis to the outer end portion is made narrower than the pitch between the springs on the second half straight line extending from the axis to the side opposite to the first half straight line, and therefore, even if the pitch between the springs is made narrower in the portion opposite to the outer end portion across the axis, the contact between the springs can be suppressed. Therefore, in the spiral spring that generates torque by winding from the pre-wind-up state, a desired torque can be generated.

In the above-described spiral spring, the following configuration is desirable: and a step of generating a torque by unwinding from the pre-wind-up state, wherein the pitch on a first half-line extending from the axis to the outer end is wider than the pitch on a second half-line extending from the axis to a side opposite to the first half-line, as viewed in the axial direction of the axis in the pre-wind-up state.

According to the present invention, if the coil spring is unwound from the pre-wind-up state, the coil spring is deformed so that the distance between the springs is increased in the portion on the opposite side of the axis to the outer end portion. Therefore, in the pre-wind-up state, the pitch between the springs on the first half straight line extending from the axis to the outer end portion is made wider than the pitch between the springs on the second half straight line extending from the axis to the side opposite to the first half straight line, and therefore, in the portion on the side opposite to the outer end portion across the axis, even if the pitch between the springs is made wider, the outermost peripheral portion of the spiral spring can be suppressed from bulging to the outside in the radial direction to a greater extent than the periphery thereof in the portion on the side opposite to the outer end portion across the axis. Therefore, the outermost peripheral portion of the coil spring can be suppressed from contacting with surrounding members. Therefore, a desired torque can be generated in the coil spring that generates a torque by unwinding from the pre-wind-up state.

In the above-described spiral spring, the following configuration is desirable: at least a portion of the coil spring extends along an archimedean curve in a state where no load is applied to the coil spring.

According to the present invention, the shape of the spiral spring in a wound state can be made to be a spiral curve similar to an archimedean curve. Therefore, in the spiral spring in the wound state, the pitch between the adjacent springs can be made substantially constant regardless of the positions in the circumferential direction and the radial direction, and therefore, the contact between the adjacent springs can be suppressed. Thus, the helical spring is able to generate a desired torque.

In the above-described coil spring, the following configuration is desirable: at least a portion of the coil spring extends along an archimedean curve with a center of the archimedean curve being disposed on a side opposite to the inner end portion with respect to the axis line in a state where no load is applied to the coil spring.

According to the present invention, the shape of the coiled coil spring can be made to be a spiral curve similar to an archimedean curve. Here, since the innermost peripheral portion of the spiral spring is reduced in diameter if the spiral spring is wound tight, the center of the spiral curve is displaced in a manner adjacent to the inner end portion as the spiral spring is wound tight. Therefore, by providing the center of the archimedean curve in a state where no load is applied to the coil spring on the opposite side of the inner end portion across the axis, the center of the coil curve is brought close to the axis in a state where the coil spring is wound tight. This makes it possible to bring the entire innermost circumferential portion of the coil spring uniformly closer to the axis, and to make the interval between the outermost circumferential portion and the innermost circumferential portion of the coil spring wider as a whole in the circumferential direction. Therefore, the distance between adjacent springs can be increased, and contact between the springs can be suppressed. Therefore, the coil spring can stably generate a desired torque.

The torque generation device of the present invention is characterized by being provided with: the above-mentioned spiral spring; the first member to which either the outer end or the inner end of the spiral spring is attached; and the second member to which the other of the outer end portion and the inner end portion of the coil spring is attached.

According to the present invention, since the coil spring generating a desired torque is provided, it is possible to suppress a shortage of torque applied between the first member and the second member.

In the above-described torque generation device, the following configuration is preferable: the constant torque mechanism is provided with: an input rotating body including the first member, rotated by power from a power source, and configured to supplement the power to the spiral spring; an output rotor including the second member, rotated by power from the coil spring, and transmitting the power of the coil spring to an actuator; and a cycle control means for intermittently rotating the input rotating body with respect to the output rotating body based on the rotation of the output rotating body.

According to the present invention, since the torque applied between the input rotator and the output rotator is stable, the fluctuation of the torque transmitted from the output rotator to the escapement can be suppressed.

In the above-described torque generation device, the following configuration is preferable: a reverse mechanism for reciprocating a hand between an initial position and a final position, comprising: a rotating part including the first member and rotating in synchronization with the pointer; and a support portion including the second member and rotatably supporting the rotating portion.

According to the present invention, it is possible to suppress the occurrence of disturbance in the repeated movement of the pointer due to insufficient torque applied to the rotary member.

In the above-described torque generation device, the following configuration is preferable: a calendar mechanism for switching the date characters indicated in a date window of a character plate, comprising: a day-change gear including the first member and rotating in synchronization with rotation of the hour wheel; and a day-change claw unit having the second member and a day-change claw provided to be engageable with and disengageable from a tooth portion of a date wheel on which the date characters are displayed, and provided to be rotatable coaxially with the day-change gear with respect to the day-change gear.

According to the present invention, it is possible to suppress the shortage of the rotational force transmitted to the date indicator due to the shortage of the torque applied to the date finger unit. Therefore, the calendar mechanism can perform a reliable day-to-day operation.

The movement for a timepiece of the present invention is characterized by being equipped with the above-described torque generation device.

The timepiece of the invention is characterized by being equipped with the movement for a timepiece described above.

According to the present invention, a movement for a timepiece and a timepiece with stable operation and high accuracy can be obtained.

ADVANTAGEOUS EFFECTS OF INVENTION

According to the present invention, it is possible to provide a spiral spring, a torque generation device, a movement for a timepiece, and a timepiece, which are capable of generating a desired torque while suppressing self-contact or contact with surrounding components.

Drawings

Fig. 1 is an external view showing a timepiece of a first embodiment;

fig. 2 is a block diagram of the movement of the first embodiment;

fig. 3 is a perspective view of a portion of the movement of the first embodiment as viewed from above;

figure 4 is a cross-sectional view showing a portion of a movement of the first embodiment;

fig. 5 is a plan view of a part of the movement of the first embodiment as viewed from above;

fig. 6 is a plan view showing the constant force spring, the fixing piece, and the fixing ring of the first embodiment;

fig. 7 is a plan view showing the constant force spring, the fixing piece, and the fixing ring of the first embodiment;

fig. 8 is a plan view showing the constant force spring, the fixing piece, and the fixing ring of the first embodiment;

fig. 9 is a plan view showing a constant force spring, a fixing piece, and a fixing ring of the second embodiment;

fig. 10 is a plan view showing a constant force spring, a fixing piece, and a fixing ring of the second embodiment;

fig. 11 is a plan view showing a constant force spring, a fixing piece, and a fixing ring of the second embodiment;

fig. 12 is a plan view showing a constant force spring, a fixing piece, and a fixing ring of the third embodiment;

fig. 13 is a plan view showing a constant force spring, a fixing piece, and a fixing ring of the third embodiment;

fig. 14 is a plan view showing a constant force spring, a fixing piece, and a fixing ring of the fourth embodiment;

fig. 15 is a plan view showing a constant force spring, a fixing piece, and a fixing ring of the fourth embodiment;

fig. 16 is a plan view showing a constant force spring, a fixing piece, and a fixing ring of the fourth embodiment;

fig. 17 is an external view showing a timepiece of a fifth embodiment;

FIG. 18 is a top plan view of the retrograde mechanism;

FIG. 19 is a top plan view of the retrograde mechanism;

fig. 20 is an external view showing a timepiece of a sixth embodiment;

fig. 21 is a plan view of the calendar mechanism as viewed from below;

fig. 22 is a top view of the sun gear (sun return し car) from below;

FIG. 23 is a top plan view of the day-change wheel as viewed from above;

FIG. 24 is a cross-sectional view taken along line XXIV-XXIV of FIG. 22;

fig. 25 is an explanatory view of the operation of the calendar mechanism, which is a plan view of a part of the calendar mechanism as viewed from below;

fig. 26 is an explanatory view of the operation of the calendar mechanism, which is a plan view of a part of the calendar mechanism as viewed from below;

fig. 27 is an explanatory view of the operation of the calendar mechanism, and is a plan view of a part of the calendar mechanism as viewed from below.

Detailed Description

Embodiments according to the present invention will be described below with reference to the drawings. In the following description, the same reference numerals are used for components having the same or similar functions. In the present embodiment, a mechanical timepiece is exemplified as an example of a timepiece.

[ first embodiment ]

(basic constitution of timepiece)

In general, a mechanical body including a drive portion of a timepiece is referred to as a "movement". The following states are referred to as "finished products" of the timepiece: the dial and the needle are mounted on the movement and put in the timepiece case to be a finished product.

Of the two sides of the main plate constituting the substrate of the timepiece, the side on which the glass of the timepiece case is present (i.e., the side on which the dial is present) is referred to as the "back side" of the movement. Of the two sides of the main plate, one side of the case back cover where the timepiece case exists (i.e., the side opposite to the dial) is referred to as the "front side" of the movement.

In the present embodiment, the direction from the dial to the case back cover is defined as upward, and the opposite side is defined as downward. Further, a direction of rotating clockwise when viewed from above is referred to as a clockwise direction, and a direction of rotating counterclockwise when viewed from above is referred to as a counterclockwise direction, with each axis of rotation as a center.

Fig. 1 is an external view showing a timepiece of a first embodiment.

As shown in fig. 1, the finished timepiece 1 of the present embodiment is equipped with, in a timepiece case constituted by a case back cover and a glass 2, not shown: a movement 10 (movement for a timepiece); a dial 3 having a scale showing at least time-related information; and hands 4 including an hour hand 5, a minute hand 6, and a second hand 7.

Fig. 2 is a block diagram of the movement of the first embodiment.

As shown in fig. 2, the movement 10 is equipped with: barrel wheel 11 as power source; a power source side gear train 12 connected to the barrel wheel 11; an actuator 14 which is regulated by the governor 13; an escapement-side wheel train 15 connected to the escapement 14; and a constant torque mechanism 30 disposed between the power source-side gear train 12 and the escaper-side gear train 15.

The constant torque mechanism 30 generally forms a part of a meter-side gear train including a second wheel, a third wheel, a fourth wheel, and the like. The power source side gear train 12 in the present embodiment is a gear train located on the barrel wheel 11 side as a power source than the constant torque mechanism 30 as viewed from the constant torque mechanism 30. Similarly, the escaper-side gear train 15 in the present embodiment refers to a gear train located closer to the escaper 14 than the constant torque mechanism 30 as viewed from the constant torque mechanism 30.

Inside the barrel wheel 11, a spiral spring 16 is accommodated. The power spring 16 is wound up by rotation of a stem shaft, not shown, coupled to the stem 17 shown in fig. 1. The barrel wheel 11 is rotated by power (torque) caused by unwinding of the power spring 16, and the power is transmitted to the constant torque mechanism 30 via the power source side gear train 12. In the present embodiment, the case where the power from the barrel wheel 11 is transmitted to the constant torque mechanism 30 via the power source side gear train 12 is described as an example, but the present invention is not limited to this case. For example, the power from the barrel wheel 11 may be directly transmitted to the constant torque mechanism 30 without via the power source-side gear train 12.

For example, the power source side gear train 12 is equipped with a first transmission wheel 18. The first transmission wheel 18 is for example a third wheel. The first transmission wheel 18 is axially supported between a main plate 23 (see fig. 4) and a train wheel bridge (not shown). Based on the rotation of the barrel wheel 11, the first transmission wheel 18 rotates. Further, if the first transmission wheel 18 rotates, a minute wheel, not shown, rotates based on the rotation. At the minute wheel, the minute hand 6 shown in fig. 1 is mounted, and the minute hand 6 is caused to display "minute" by the rotation of the minute wheel. The minute hand 6 rotates at a rotational speed regulated by the escapement 14 and the speed regulator 13 (i.e., once in one hour).

Further, if the first transmission wheel 18 rotates, the unillustrated straddle wheel rotates based on the rotation, and the unillustrated hour wheel rotates based on the rotation of the straddle wheel. At the hour wheel, an hour hand 5 shown in fig. 1 is mounted, and the hour hand 5 displays "hour" by rotation of the hour wheel. The hour hand 5 rotates at a rotational speed regulated by the escapement 14 and the speed regulator 13 (for example, once in twelve hours).

The escapement-side wheel train 15 is mainly equipped with a second transmission wheel 19. The second transmission wheel 19 is for example a fourth wheel. The second transmission wheel 19 is axially supported between the main plate 23 and the train wheel bridge, and rotates based on rotation of a constant force lower stage wheel 60 (see fig. 3) described later of the constant torque mechanism 30. In the case where the second transmission wheel 19 is the fourth wheel, the second hand 7 shown in fig. 1 is attached to the second transmission wheel 19, and the second hand 7 displays "seconds" based on the rotation of the second transmission wheel 19. The second hand 7 rotates at a rotational speed regulated by the escapement 14 and the speed regulator 13 (for example, once in one minute).

The escapement 14 is mainly equipped with an escape wheel and an anchor (both not shown).

The escape wheel shaft is supported between the main plate 23 and the train wheel bridge, for example, meshed with the second transmission wheel 19. Thereby, power from a constant force spring 100 (see fig. 3) described later in the constant torque mechanism 30 is transmitted to the escape wheel via the escapement-side wheel train 15. Thereby, the escape wheel is rotated by the power from the constant force spring 100.

The anchor is rotatably (swingably) supported between the main plate 23 and an anchor clamp plate (not shown), and includes a pair of pallet stones (claw stones), not shown. The pair of pallet stones are alternately engaged and disengaged with respect to the escape tooth of the escape wheel at a predetermined cycle by the speed controller 13. This enables the escape wheel to escape at a predetermined cycle.

The governor 13 is mainly provided with a balance (not shown).

A balance wheel (て brake ぷ) is equipped with a balance shaft (て brake), a balance wheel (て brake) and a balance spring (ひ - ぜ brake まい), which is supported between the main plate 23 and a balance bridge (not shown). The balance wheel rotates reciprocally (rotates forward and backward) at a constant cycle using the balance spring as a power source.

(constitution of constant Torque mechanism)

The constant torque mechanism 30 is a mechanism that suppresses variation in power (torque variation) transmitted to the escapement 14.

Fig. 3 is a perspective view of a part of the movement of the first embodiment as viewed from above.

As shown in fig. 3, the constant torque mechanism 30 is equipped with: a fixed gear 31 having a first rotation axis O1 extending up and down as a center axis; a constant-force upper stage wheel 40 (input rotary body) that rotates about a first rotation axis O1; a constant force lower stage wheel 60 (output rotary body) disposed coaxially with the constant force upper stage wheel 40 and capable of relative rotation with respect to the constant force upper stage wheel 40 about a first rotation axis O1; a click disengaging lever unit 80 that couples the constant force upper stage wheel 40 and the constant force lower stage wheel 60; a constant force spring 100 that transmits the accumulated power to the constant force upper stage wheel 40 and the constant force lower stage wheel 60; and a torque adjusting mechanism 110 that adjusts the torque of the constant force spring 100. The first rotation axis O1 is disposed at a position offset in the in-plane direction of the main plate 23 (see fig. 4) with respect to the rotation axes of the first transfer roller 18 and the second transfer roller 19 (see fig. 2).

Fig. 4 is a sectional view showing a part of the movement of the first embodiment.

As shown in fig. 4, the fixed gear 31 is disposed between the main plate 23 and the constant force unit bridge plate 24. The constant force unit clamp plate 24 is disposed above the main plate 23. The fixed gear 31 is equipped with: a cylinder 32 disposed coaxially with the first rotation axis O1; and a gear main body 33 formed integrally with the cylinder 32.

The cylinder 32 is fixed to the lower surface of the constant force unit clamp plate 24 by a fixed gear pin 34 projecting downward from the constant force unit clamp plate 24. The cylinder 32 has a center hole 35 and a window 36. The center hole 35 extends vertically with a constant inner diameter around the first rotation axis O1, and vertically penetrates the cylinder 32. The window portion 36 is adjacent to the center hole 35 in a direction in which the first rotation axis O1 and the rotation axis of the first transmission wheel 18 are aligned when viewed in the vertical direction (see fig. 3). The window 36 vertically penetrates the cylindrical body 32 and is connected to the center hole 35. Thus, the hole penetrating the fixed gear 31 in the vertical direction becomes a long hole when viewed in the vertical direction.

The gear main body 33 is formed coaxially with the first rotation axis O1 and protrudes outward in the radial direction from the lower end portion of the cylinder 32. The gear main body 33 has a fixed tooth 33a formed on the outer peripheral surface thereof over the entire periphery. That is, the fixed gear 31 is an external gear type gear.

The constant force upper wheel 40 is pivotally supported between the main plate 23 and the constant force unit clamping plate 24. The constant force upper stage wheel 40 is equipped with: a rotary shaft 41 that rotates about a first rotation axis O1; a planetary wheel 43 that revolves around a first rotation axis O1; and a carrier 47 (first member) that shaft-supports the planetary wheels 43.

The rotary shaft 41 extends along the first rotation axis O1. The rotary shaft 41 is supported by the main plate 23 and the constant force unit clamp plate 24 through the holed jewels (pocket stones) 25A and 25B. The holey gemstones 25A, 25B are formed of artificial gemstones such as ruby. The holey gems 25A and 25B are not limited to those formed of artificial gems, and may be formed of other brittle materials or metal materials such as iron-based alloys. A constant-force upper pinion gear (かな)41a is formed on the upper portion of the rotary shaft 41. The constant-force upper-stage pinion 41a meshes with the first transmission wheel 18. Thereby, power from the barrel wheel 11 (refer to fig. 2) is transmitted to the rotary shaft 41 via the power source side gear train 12. The power of torque Tb is transmitted from barrel 11 to rotary shaft 41. Hereinafter, the torque Tb is referred to as a rotation torque Tb of the barrel 11. The rotation shaft 41 is rotated in the clockwise direction by the power from the barrel wheel 11.

The carrier 47 is fixedly supported to the rotary shaft 41. The clockwise rotation torque Tb from the rotating shaft 41 is transmitted to the carrier 47. Thereby, the carrier 47 is rotated in the clockwise direction about the first rotation axis O1 together with the rotation shaft 41 by the power from the barrel wheel 11. The carrier 47 is equipped with: a lower seat 48 integrally coupled to the rotary shaft 41; and an upper seat 54 disposed above the lower seat 48 and fixed to the lower seat 48.

The lower seat 48 is disposed below the fixed gear 31. The lower seat 48 is equipped with: a planet wheel support portion 49 that supports the planet wheels 43; a spring support portion 50 supporting the constant force spring 100; and a coupling portion 51 that couples the planet wheel support portion 49 and the spring support portion 50.

Fig. 5 is a plan view of a part of the movement of the first embodiment as viewed from above. In fig. 5, a part of the fixed gear 31 is broken and shown.

As shown in fig. 3 and 5, the planet wheel support portion 49 extends in a circular arc shape in a circumferential direction around the first rotation axis O1 as viewed from the up-down direction. The planet wheel supporting portion 49 is formed such that an intermediate portion thereof, as viewed in the vertical direction, is lowered one step downward than both end portions thereof.

As shown in fig. 4, the spring support portion 50 is provided on the opposite side of the planet wheel support portion 49 with respect to the first rotation axis O1. The spring support portion 50 is formed with a pin insertion through hole 50a through which a constant force spring pin 103 described later is inserted. In the coupling portion 51, a center hole through which the rotation shaft 41 is inserted is formed. The coupling portion 51 is fixed to a lower portion of the rotary shaft 41 than the constant-force upper pinion 41 a. Thereby, the lower seat 48 rotates integrally with the rotary shaft 41. In the lower seat 48, a carrier window portion 52 is formed. The carrier window portion 52 is formed on the first rotation axis O1 side with respect to the planet wheel support portion 49. The carrier window 52 vertically penetrates the lower seat 48. The carrier window 52 prevents the lower seat 48 from coming into contact with an engagement pallet 86, which will be described later.

As shown in fig. 3, the upper seat 54 is disposed above the planet wheel support portion 49 of the lower seat 48, and is further disposed above than the gear main body 33 of the fixed gear 31. The upper seat 54 extends in an arc shape in a circumferential direction around the first rotation axis O1 as viewed in the vertical direction. The upper seat 54 is stacked with a plurality of collars 55 spaced apart from the planet wheel support portion 49 of the lower seat 48. Both end portions of the upper seat 54 are fixed to both end portions of the planet wheel support portion 49 by a plurality of bolts 56 inserted through a plurality of collars 55.

As shown in fig. 4, the planetary wheels 43 are supported on the carrier 47 in a rotatable manner. Specifically, the planetary gear 43 is supported by the planetary gear support portion 49 of the lower carrier 48 and the upper carrier 54 via the

holey stones

59A and 59B, and is rotatable about the second rotation axis O2. The second rotation axis O2 is disposed at a position fixed to the carrier 47 (a position offset in the in-plane direction of the main plate 23 with respect to the first rotation axis O1). The planetary gears 43 are disposed between an intermediate portion of the planetary gear support portion 49 of the lower seat 48 as viewed in the vertical direction and an intermediate portion of the upper seat 54 as viewed in the vertical direction (see fig. 3). The planet wheel 43 is equipped with a planet pinion 44 and a planet gear 45.

The planetary pinion 44 meshes with the fixed teeth 33a of the fixed gear 31. Since the fixed gear 31 is of the external-tooth type, the planetary gear 43 revolves around the first rotation axis O1 in the clockwise direction while rotating in the clockwise direction around the second rotation axis O2 in association with the clockwise rotation of the carrier 47 by the meshing of the planetary pinion 44 with the fixed gear 31.

The planetary gear 45 is formed further downward than the planetary pinion 44, and can rotate (can rotate and revolve) without contacting the fixed gear 31. The planetary gear 45 has a plurality of stopper teeth 45a that can engage with and disengage from the engagement yoke 86. The number of the stop teeth 45a becomes 8 teeth. However, the number of teeth is not limited to this case, and may be appropriately changed.

As shown in fig. 5, the stopper tooth 45a extends in the clockwise direction around the second rotation axis O2 as being separated from the second rotation axis O2 as viewed from the up-down direction. The tip of the stopper tooth 45a serves as an engagement surface for engaging and disengaging with respect to the engagement yoke shoe 86. Hereinafter, a rotation locus M drawn by the tooth tip of the stopper tooth 45a accompanying the rotation of the planetary gear 43 is referred to as a rotation locus M of the planetary gear 45.

As shown in fig. 4, the constant-force lower stage wheel 60 is rotatably supported on the rotating shaft 41 of the constant-force upper stage wheel 40 between the main plate 23 and the constant-force unit bridge plate 24. The constant force lower wheels 60 are disposed between the carrier 47 and the main plate 23 (which is located below the carrier 47 of the constant force upper wheels 40). The constant force lower stage wheel 60 is equipped with: a constant lower cylinder 61 (second member) inserted into the rotary shaft 41; and a constant force lower stage gear 62 integrally coupled to the constant force lower stage cylinder 61. Further, the constant-force lower stage wheel 60 rotates in the clockwise direction about the first rotation axis O1 by the power transmitted from the constant-force spring 100.

In the lower constant force cylinder 61, the rotary shaft 41 is inserted through from above and protrudes below the lower constant force cylinder 61.

Annular hole stones

69A and 69B are press-fitted into the upper end portion and the lower end portion of the lower constant force stage cylinder 61. The rotary shaft 41 is inserted through the insides of the

hole stones

69A and 69B.

The constant force lower stage gear 62 is integrally coupled to a lower end portion of the constant force lower stage cylinder 61. The constant force lower stage teeth 62a, which the second transmission wheel 19 engages with, are formed on the outer peripheral surface of the constant force lower stage gear 62 over the entire circumference. Thereby, the constant force lower stage wheel 60 can transmit the power from the constant force spring 100 to the second transmission wheel 19 (i.e., the escapement-side train wheel 15) connected to the escapement 14.

In the present embodiment, the case where the power from the constant force spring 100 is transmitted to the escapement 14 via the escapement-side wheel train 15 is described as an example, but the present invention is not limited to this case. For example, the power from the constant force spring 100 may be directly transmitted to the escapement 14 without providing the escapement-side wheel train 15.

The engagement/disengagement lever unit 80 includes an engagement fork shoe 86 that is engaged with and disengaged from the stopper tooth 45a of the planetary gear 45, and supports the engagement fork shoe 86 so as to be rotatable about the first rotation axis O1. The engagement release lever unit 80 is equipped with: a lever bush (レバーブッシュ)81 provided so as not to rotate relative to the constant force lower stage cylinder 61; and an engagement/disengagement lever 84 provided so as to be rotatable in the clockwise direction in accordance with the clockwise rotation of the lever bush 81.

The lever bush 81 is formed in a cylindrical shape coaxial with the first rotation axis O1. The lever bushing 81 is externally fitted to an upper end portion of the constant force lower stage cylinder 61 of the constant force lower stage wheel 60, and is integrally coupled to the constant force lower stage cylinder 61. Thereby, the lever bushing 81 rotates in the clockwise direction about the first rotation axis O1 in synchronization with the rotation of the constant-force lower stage wheel 60.

The engagement and disengagement lever 84 is provided with a lever main body 85 and an engagement pallet 86 supported by the lever main body 85.

The lever main body 85 is disposed below the planetary gear 45 of the planetary gear 43. The lever main body 85 is supported by the lever bushing 81. An engagement pallet 86 is attached to one end of the lever main body 85.

The snap pallet 86 is formed of an artificial gem such as ruby. The engaging pallet 86 is not limited to being formed of an artificial gem as in the case of the aforementioned hole gem, and may be formed of other brittle materials or metal materials such as iron-based alloys. The engagement yoke 86 may be formed integrally with the lever main body 85, instead of being separate from the lever main body 85. The engagement yoke 86 is held by the lever main body 85 in a state of protruding to the planetary gear 45 side (upper side) than the lever main body 85. The engagement pallet 86 is disposed inside the carrier window 52 of the carrier 47 of the constant force upper stage wheel 40.

As shown in fig. 5, with respect to the side surface of the protruding portion of the engaging pallet 86 that faces the side opposite to the first rotation axis O1, the tooth tip of the stopper tooth 45a of the planetary gear 45 can be engaged and disengaged. Engagement yoke 86 engages planetary gear 45 within rotation locus M of planetary gear 45 to restrict rotation of planetary gear 43. The engagement yoke 86 is displaced in the clockwise direction around the first rotation axis O1 with respect to the planetary gear 43, retreats from the rotation locus M of the planetary gear 45, and is disengaged from the stopper tooth 45a to release the engagement with the planetary gear 45.

As shown in fig. 3, the constant force spring 100 is a helical spring composed of a metal or alloy such as iron or nickel, a non-metal such as silicon, or the like. The constant force spring 100 is disposed between the engaging and disengaging lever unit 80 and the constant force lower stage gear 62 (below the engaging and disengaging lever unit 80).

Fig. 6 is a plan view showing the constant force spring, the fixing piece, and the fixing ring of the first embodiment. Fig. 6 shows a torque generation state of the constant force spring 100, which will be described later. In fig. 6, hatching is applied to the constant force spring 100, the fixing piece 105, and the fixing ring 104 (the same applies to the following plan view) for easy viewing of the drawing.

As shown in fig. 6, the constant force spring 100 is equipped with an outer end portion 101 as one circumferential end portion and an inner end portion 102 as the other circumferential end portion. As shown in fig. 4, the outer end 101 of the constant force spring 100 is mounted to the lower seat 48 of the carrier 47 of the constant force upper wheel 40 via a fixing plate 105 and a constant force spring pin 103. The inner end 102 of the constant force spring 100 is mounted to the constant force idler 60 via a retaining ring 104 and a torque adjustment mechanism 110. Thereby, the constant force spring 100 can transmit the stored power to the constant force upper stage wheel 40 and the constant force lower stage wheel 60, respectively. The detailed shape of the constant force spring 100 is explained later.

As shown in fig. 6, the fixing plate 105 is connected to the outer end 101 of the constant force spring 100. In the illustrated example, the fixing piece 105 is integrally formed with the constant force spring 100. The fixing piece 105 is formed with a through hole 105a through which the constant force spring pin 103 (see fig. 4) is inserted.

As shown in fig. 4, the fixing piece 105 is disposed below the spring support portion 50 of the constant force raising roller 40. The constant force spring pin 103 is held by the spring support portion 50 in a state of protruding downward from a pin insertion through hole 50a formed in the spring support portion 50 of the constant force upper stage wheel 40. The protruding portion of the constant force spring pin 103 is inserted into the through hole 105a of the fixing piece 105 from above. Thereby, the constant force spring pin 103 connects the fixed piece 105 and the constant force upgrading wheel 40.

As shown in fig. 6, the fixing ring 104 is formed in a circular ring shape coaxial with the first rotation axis O1. A part of the outer peripheral surface of the fixed ring 104 protrudes to the outside in the radial direction, and is connected to the inner end portion 102 of the constant force spring 100. In the illustrated example, the retaining ring 104 is integrally formed with the constant force spring 100. The fixed ring 104 is integrally coupled to a constant force spring bushing 111 (see fig. 4) of the torque adjustment mechanism 110, which will be described later.

The constant force spring 100 is wound by a predetermined amount in a clockwise direction toward the outer end 101 with the inner end 102 as an unwinding position. A preload is applied to the constant force spring 100 by wind-up. Therefore, the constant force spring 100 generates power of the torque Tc and accumulates the power. In the present embodiment, the constant force spring 100 is elastically deformed to have a reduced diameter by tightening the outer end portion 101 in the clockwise direction with respect to the inner end portion 102, thereby generating a torque.

The power accumulated in the constant force spring 100 is transmitted to the constant force upper stage wheel 40 and the constant force lower stage wheel 60 along with the elastic restoring deformation of the constant force spring 100. Thus, the constant force upper sheave 40 and the constant force lower sheave 60 can be rotated in mutually opposite directions about the first rotation axis O1 by the power transmitted from the constant force spring 100. Specifically, the constant force lower stage wheel 60 can rotate in a clockwise direction, and the constant force upper stage wheel 40 can rotate in a counterclockwise direction. Hereinafter, the torque Tc is referred to as a rotation torque Tc of the constant force spring 100. When the mainspring 16 in the barrel wheel 11 is wound up by a predetermined winding amount, the rotational torque Tc becomes smaller than the rotational torque Tb of the rotational shaft 41.

As shown in fig. 4, the torque adjustment mechanism 110 applies a preload to the constant force spring 100 to adjust the rotational torque Tc of the constant force spring 100. The torque adjustment mechanism 110 includes: a constant force spring bushing 111 supported by the constant force lower stage cylinder 61 of the constant force lower stage wheel 60; a first torque adjustment gear 112 integrally coupled to the constant force spring bushing 111; a second torque adjustment gear 113 integrally coupled to the constant force lower stage cylinder 61; and a torque adjustment jumper 114 that couples the first torque adjustment gear 112 and the second torque adjustment gear 113.

The constant force spring bushing 111 is formed in a cylindrical shape coaxial with the first rotation axis O1. The constant force spring bushing 111 is externally inserted into the constant force lower stage cylinder 61 between the constant force lower stage gear 62 and the engaging and disengaging lever unit 80. The constant force spring bushing 111 is disposed rotatably about the first rotation axis O1 with respect to the constant force lower stage cylinder 61. The above-described fixing ring 104 is externally inserted into the upper and lower intermediate portions of the constant force spring bushing 111, and the constant force spring bushing 111 and the fixing ring 104 are integrally coupled.

The first torque adjustment gear 112 is integrally coupled to a lower end portion of the constant force spring bushing 111. First torque adjustment teeth 112a are formed on the outer peripheral surface of the first torque adjustment gear 112 over the entire circumference. A gear for torque adjustment, not shown, is engaged with the first torque adjustment teeth 112 a.

The second torque adjustment gear 113 is disposed between the constant force lower stage gear 62, the constant force spring bushing 111, and the first torque adjustment gear 112. The second torque adjustment gear 113 is integrally coupled to the constant force lower stage cylinder 61. The second torque adjustment gear 113 is formed with a smaller diameter than the first torque adjustment gear 112. Second torque adjustment teeth 113a are formed on the outer peripheral surface of the second torque adjustment gear 113 over the entire circumference. The torque adjustment jumper 114 is detachably engaged with the second torque adjustment teeth 113 a.

The torque adjustment jumper 114 is supported by the first torque adjustment gear 112 and can revolve around the second torque adjustment gear 113 around the first rotation axis O1. The torque adjustment jumper 114 can restrict the clockwise rotation of the first torque adjustment gear 112 with respect to the second torque adjustment gear 113. The torque adjustment jumper 114 can allow the first torque adjustment gear 112 to rotate counterclockwise with respect to the second torque adjustment gear 113.

Thus, if the constant force spring bushing 111 and the first torque adjustment gear 112 receive clockwise power from the constant force spring 100, the power is transmitted to the second torque adjustment gear 113 via the torque adjustment jumper 114. Then, the torque adjustment jumper 114 restricts the clockwise rotation of the first torque adjustment gear 112 with respect to the second torque adjustment gear 113, and the first torque adjustment gear 112 and the second torque adjustment gear 113 rotate integrally in the clockwise direction. As a result, the constant-force lower stage wheel 60 also rotates in the clockwise direction together with the second torque adjustment gear 113.

In addition, when a preload is applied to the constant force spring 100, the gear for torque adjustment, which is not shown, is rotated by meshing the gear for torque adjustment with the first torque adjustment gear 112, so that the first torque adjustment gear 112 is rotated in the counterclockwise direction. Then, since the torque adjustment jumper 114 allows the counterclockwise rotation of the first torque adjustment gear 112 with respect to the second torque adjustment gear 113, the constant force lower stage wheel 60 is not rotated, but the constant force spring bushing 111 and the fixed ring 104 are rotated in the counterclockwise direction. Thereby, the inner end portion 102 of the constant force spring 100 can be rotated in the counterclockwise direction. As a result, the constant force spring 100 can be wound up, and the preload of the constant force spring 100 can be increased to adjust the rotational torque Tc to be increased.

(shape of constant force spring)

Next, the shape of the constant force spring 100 will be described. In the following description, the following state is referred to as a natural state of the constant force spring 100: the constant force spring 100 is not mounted to the constant force upper sheave 40 and the constant force lower sheave 60, and a load is not applied to the constant force spring 100. The following state is referred to as an attachment state of the constant force spring 100: the outer end 101 of the constant force spring 100 is mounted to the constant force upper stage wheel 40, and the inner end 102 of the constant force spring 100 is mounted to the constant force lower stage wheel 60. In addition, a state in which no torque is generated (before the constant force spring 100 is wound up) in the attached state of the constant force spring 100 is referred to as a pre-winding state, and a state in which the constant force spring 100 is wound up to generate a predetermined torque is referred to as a torque generation state. The same applies to other embodiments described later.

Fig. 7 is a plan view showing the constant force spring, the fixing piece, and the fixing ring of the first embodiment. In fig. 7, the natural state of the constant force spring 100 is shown.

As shown in fig. 7, in a natural state, the constant force spring 100 extends along an archimedean curve centered on the central axis X of the stationary ring 104. Thereby, the interval between the adjacent springs becomes constant. The center axis X of the fixed ring 104 is an axis that coincides with the first rotation axis O1 in a state where the fixed ring 104 is attached to the constant force idler 60 via the torque adjustment mechanism 110. That is, the center axis X of the fixed ring 104 is the rotation center of the constant force spring 100 when wound. In a natural state, the constant force spring 100 is formed in such a manner that the outer end portion 101 is deviated by 90 ° in a counterclockwise direction around the center axis X of the fixed ring 104 with respect to the inner end portion 102.

Fig. 8 is a plan view showing the constant force spring, the fixing piece, and the fixing ring of the first embodiment. Fig. 8 shows the constant force spring 100 in a pre-wind-up state.

As shown in fig. 8, in the pre-wind-up state of the constant force spring 100, the outer end portion 101 of the constant force spring 100 is disposed at a position closer to the first rotation axis O1 than the position a in the natural state. The distance between the outer end 101 and the inner end 102 is smaller in the pre-wind-up state than in the natural state. In the present embodiment, in the pre-wind-up state of the constant force spring 100, the outer end 101 of the constant force spring 100 is disposed between the position a in the natural state and the first rotation axis O1. Thus, in the constant force spring 100 in the pre-wind-up state, the spacing between the springs adjacent in the radial direction orthogonal to the first rotation axis O1 varies depending on the position in the circumferential direction around the first rotation axis O1.

Specifically, the pitch P1 between the springs on the first half straight line L1 extending from the first rotation axis O1 to the outer end 101 is smaller than the pitch P2 between the springs on the second half straight line L2 extending from the first rotation axis O1 to the side opposite to the first half straight line L1 as viewed in the up-down direction. The pitch P1 between the springs on the first half-straight line L1 is smaller than that in the natural state, and becomes smaller as it goes away from the first rotation axis O1. The pitch P2 between the springs on the second half-straight line L2 is larger than that in the natural state, and becomes larger as it goes away from the first rotation axis O1. In the pre-wind-up state of the constant force spring 100, the adjacent springs may contact each other.

The constant force spring 100 is in the torque generation state shown in fig. 6 by rotating the inner end portion 102 by a predetermined angle (360 ° in the illustrated example) in the counterclockwise direction from the pre-wind-up state by the torque adjustment mechanism 110 and winding up the constant force spring 100. In the torque generating state, the constant force spring 100 extends along a spiral curve that approximates an archimedean curve centered on a position deviated from the first rotation axis O1 to the inner end portion 102 side. In the torque generating state, with respect to the constant force springs 100, adjacent springs are separated from each other to avoid self-contact.

(operation of constant Torque mechanism)

Next, the operation of the constant torque mechanism 30 configured as described above will be described.

Further, as an initial state, the power spring 16 in the barrel drum 11 is wound up by a predetermined winding amount, and the power of the rotational torque Tb is transmitted from the barrel drum 11 to the carrier 47 of the constant force sheave 40 via the power source side gear train 12. The constant force spring 100 is wound up by a predetermined amount, and the power of the rotational torque Tc smaller than the rotational torque Tb is transmitted from the constant force spring 100 to the carrier 47 of the constant force upper stage wheel 40 and the constant force lower stage wheel 60.

According to the constant torque mechanism 30 of the present embodiment, since the constant force spring 100 is provided, the power accumulated in the constant force spring 100 can be transmitted to the constant force lower stage wheel 60, and the constant force lower stage wheel 60 can be rotated in the clockwise direction about the first rotation axis O1. In detail, the power from the constant force spring 100 is transmitted to the torque adjustment mechanism 110 via the fixed ring 104. The power transmitted to the torque adjustment mechanism 110 is transmitted to the constant force lower stage wheels 60. Thereby, power, such as rotating in a clockwise direction about the first rotation axis O1 with the rotational torque Tc, is transmitted from the constant force spring 100 to the constant force lower sheave 60. The power of the constant force spring 100 can be transmitted from the constant force lower stage gear 60 to the second transmission gear 19, and the second transmission gear 19 can be rotated in accordance with the rotation of the constant force lower stage gear 60. That is, the power from the constant force spring 100 can be transmitted to the escapement-side gear train 15 via the constant force lower stage wheel 60, and the escapement 14 can be operated.

In addition, since the power from the constant force spring 100 is also transmitted to the constant force geneva wheel 40 via the fixing plate 105 and the constant force spring pin 103, the constant force geneva wheel 40 will be caused to rotate in the counterclockwise direction about the first rotation axis O1 with the rotation torque Tc.

However, a rotational torque Tb, which is rotated in the clockwise direction about the first rotation axis O1, is transmitted from the power source side train wheel 12 to the constant force higher stage wheel 40. Since the rotational torque Tb is greater than the rotational torque Tc, the constant force upper sheave 40 is prevented from rotating in the counterclockwise direction about the first rotational axis O1.

Further, a differential power (rotational torque Tb — rotational torque Tc) between the rotational torque Tb transmitted from the power source side gear train 12 and the rotational torque Tc transmitted from the constant force spring 100 acts on the constant force upper wheels 40. However, since the engagement yoke 86 of the engagement/disengagement lever unit 80 engages with the planetary gear 45 within the rotation locus M of the planetary gear 45 of the constant force stepped-up gear 40, the rotation and revolution of the planetary gear 43 are restricted. Thereby, the constant force upper stage wheel 40 and the constant force lower stage wheel 60 can be coupled, and the constant force upper stage wheel 40 can be prevented from rotating clockwise about the first rotation axis O1.

As described above, the constant force upshift wheel 40 is prevented from rotating about the first rotation axis O1 at the stage when the planetary gear 45 and the engagement pallet 86 are engaged. Further, since the differential power described above acts on the constant force upper stage wheel 40, the tooth tips of the stopper teeth 45a of the planetary gear 45 are engaged in a state of being strongly pushed against the engagement yoke 86.

If the constant-force lower stage wheel 60 is rotated by the power from the constant-force spring 100, the lever bushing 81 of the engagement and disengagement lever unit 80 and the engagement and disengagement lever 84 are rotated in the clockwise direction about the first rotation axis O1 concomitantly therewith. If the click-off lever 84 is rotated in the clockwise direction, the click pallet 86 included in the click-off lever 84 is displaced in the clockwise direction about the first rotation axis O1. Thus, the engagement/disengagement lever unit 80 can gradually disengage the engagement fork shoe 86 from the planetary gear 45 so as to retreat from the rotation locus M of the planetary gear 45. As a result, the tip of the stopper tooth 45a moves counterclockwise about the first rotation axis O1 with respect to the engagement yoke shoe 86 while sliding to the engagement yoke shoe 86 as the engagement yoke shoe 86 is disengaged. Then, when the tooth tip of the stopper tooth 45a exceeds the claw tip of the engaging yoke shoe 86, the engagement between the stopper tooth 45a and the engaging yoke shoe 86 is released. Thereby, the constant force upper stage wheel 40 and the constant force lower stage wheel 60 are decoupled from each other via the engagement pallet 86 and the planetary gear 43.

Therefore, the constant force upper stage wheel 40 rotates in the clockwise direction about the first rotation axis O1 by the power of the difference between the rotational torque Tb transmitted from the power source side gear train 12 and the rotational torque Tc transmitted from the constant force spring 100 (rotational torque Tb — rotational torque Tc).

The constant force upper pulley 40 rotates clockwise about the first rotation axis O1, whereby the constant force spring 100 can be wound up via the constant force spring pin 103 fixed to the carrier 47, and power can be supplemented to the constant force spring 100. That is, the loss amount of power lost by the transmission of power to the constant-force lower stage wheel 60 can be supplemented by the power transmitted from the barrel wheel 11 side as a power source. This can maintain the constant power of the constant force spring 100, and can operate the escapement 14 with a constant torque.

Even when the power of the constant force spring 100 is supplemented, the constant force lower stage wheel 60 rotates by the power from the constant force spring 100, and transmits the power from the constant force spring 100 to the escapement side wheel train 15.

When the power of the constant force spring 100 is supplemented, the planetary gear 43 revolves clockwise around the first rotation axis O1 while rotating clockwise around the second rotation axis O2 in accordance with the rotation of the constant force geneva wheel 40 around the first rotation axis O1, and follows the engagement pallet 86. Then, the planet wheel 43 rotates by 1 tooth of the stopper tooth 45a, and the tooth tip of the stopper tooth 45a catches up with the engagement yoke shoe 86 and engages with the engagement yoke shoe 86 again.

Thus, the constant force upgrading wheel 40 and the constant force downgrader wheel 60 are coupled to each other again, and therefore, the rotation of the constant force upgrading wheel 40 is prevented, and the supplement of the power to the constant force spring 100 is completed.

The engagement and disengagement of the planetary gear 45 and the engagement yoke 86 can be intermittently performed by repeating the above. That is, the planetary gear 45 and the engagement pallet 86 can intermittently rotate the constant force higher stage wheel 40 with respect to the constant force lower stage wheel 60 based on the rotation of the constant force lower stage wheel 60. This allows the power of the constant force spring 100 to be intermittently supplemented.

(constant force spring action)

Next, the operation of the constant force spring 100 configured as described above will be described.

If a coil spring such as the constant force spring 100 is wound around an axis by winding from a natural state, the diameter will be reduced centering on the axis. Therefore, if the spiral spring is wound while keeping the distance between the axis and the outer end portion and the inner end portion constant, the spiral spring is deformed by receiving a force in the radial direction from the outer end portion and the inner end portion. When the coil spring is wound from the pre-wind-up state as in the constant force spring 100 of the present embodiment, the entire coil spring is deformed so as to be stretched by the outer end portion, and the pitch between the adjacent springs is narrowed in a portion on the opposite side of the outer end portion with respect to the axis line compared to the pre-wind-up state.

With the constant force spring 100 of the present embodiment, in the pre-wind-up state, the pitch between the springs adjacent in the radial direction orthogonal to the first rotation axis O1 varies depending on the position in the circumferential direction around the first rotation axis O1. According to this configuration, the shape of the constant force spring 100 in the torque generation state can be arbitrarily adjusted by appropriately adjusting and changing the pitch between the adjacent springs according to the position in the circumferential direction. Therefore, the distance between the springs is narrowed by the deformation accompanying the winding-up of the constant force spring 100, and the springs can be suppressed from contacting each other. Thus, the reduction of the torque generated by the constant force spring 100 can be suppressed by the frictional force caused by the contact of the constant force spring 100 in the torque generation state. Therefore, the constant force spring 100 can suppress self-contact or contact to surrounding components and generate a desired torque.

The constant-force spring 100 is formed so as to generate a torque by winding from a pre-wind-up state in which a pitch P1 between springs on a first half straight line L1 extending from the first rotation axis O1 to the outer end 101 is narrower than a pitch P2 between springs on a second half straight line L2 extending from the first rotation axis O1 to the opposite side of the first half straight line L1 as viewed in the vertical direction. According to this configuration, if the constant force spring 100 is wound up from the pre-wind-up state, the distance between the springs is deformed so as to be narrowed in a portion on the opposite side of the outer end portion 101 across the first rotation axis O1. Therefore, in the pre-wind-up state, the pitch P1 between the springs on the first half straight line L1 extending from the first rotation axis O1 to the outer end 101 is made narrower than the pitch P2 between the springs on the second half straight line L2 extending from the first rotation axis O1 to the opposite side to the first half straight line L1, whereby the contact between the springs can be suppressed even if the pitch between the springs is narrowed in the portion on the opposite side to the outer end 101 across the first rotation axis O1. Therefore, in the constant force spring 100 that generates a torque by winding from the pre-wind-up state, a desired torque can be generated.

In addition, in a natural state where no load is applied to the constant force spring 100, the constant force spring 100 extends along the archimedes curve. According to this configuration, the shape of the constant force spring 100 in the torque generation state can be made to be a spiral curve similar to an archimedean curve. Therefore, in the constant force spring 100 in the torque generation state, the pitch between the adjacent springs can be made substantially constant regardless of the positions in the circumferential direction and the radial direction, and therefore, the contact between the adjacent springs can be suppressed. Thus, the constant force spring 100 is able to generate a desired torque.

Further, since the constant torque mechanism 30 of the present embodiment includes the constant force spring 100 that generates a desired torque, it is possible to suppress a shortage of the torque applied between the constant force upper stage wheel 40 and the constant force lower stage wheel 60, and to suppress a variation of the torque transmitted from the constant force lower stage wheel 60 to the escapement 14.

In addition, since the timepiece 1 and the movement 10 according to the present embodiment are equipped with the constant torque mechanism 30 that suppresses the fluctuation of the torque transmitted to the escapement 14, the movement 10 and the timepiece 1 can be realized with high accuracy.

[ second embodiment ]

Next, a second embodiment will be described with reference to fig. 9 to 11. In the second embodiment, at a point where a part of the outermost peripheral portion in the constant force spring 200 is separated from the outside in the radial direction via the crank portion 206, it is different from the first embodiment. The configuration other than the configuration described below is the same as that of the first embodiment.

Fig. 9 is a plan view showing a constant force spring, a fixing piece, and a fixing ring of the second embodiment. In fig. 9, the natural state of the constant force spring 200 is shown.

As shown in fig. 9, the constant force spring 200 is equipped with: an outer end portion 201 to which the fixing piece 105 is attached; an inner end portion 202 to which the fixing ring 104 is attached; and a crank portion 206. The crank portion 206 displaces a part of the outermost periphery of the constant force spring 200 including the outer end portion 201 to the outside in the radial direction. Thus, in the natural state, the portion of the constant force spring 200 other than a part of the outermost peripheral portion extends along the archimedean curve centered on the central axis X of the fixed ring 104. In addition, with respect to a part of the outermost periphery of the constant force spring 200 including the outer end portion 201, the interval between the adjacent springs is wider than the other parts.

Fig. 10 is a plan view showing a constant force spring, a fixing piece, and a fixing ring of the second embodiment. In fig. 10, the constant force spring 200 is shown in a pre-wind-up state.

As shown in fig. 10, in the pre-wind-up state of the constant force spring 200, the outer end portion 201 of the constant force spring 200 is disposed at a position closer to the first rotation axis O1 than the position B in the natural state. Thus, in the constant force spring 200 in the pre-wind-up state, as in the constant force spring 100 of the first embodiment, the pitch between the springs adjacent in the radial direction orthogonal to the first rotation axis O1 varies depending on the position in the circumferential direction around the first rotation axis O1.

Specifically, the pitch P1 between the springs on the first half straight line L1 extending from the first rotation axis O1 to the outer end 201 is smaller than the pitch P2 between the springs on the second half straight line L2 extending from the first rotation axis O1 to the side opposite to the first half straight line L1 as viewed in the up-down direction. The pitch P1 between the springs on the first half-straight line L1 is smaller than that in the natural state, and becomes smaller as it goes away from the first rotation axis O1 except for the outermost peripheral portion. The pitch P2 between the springs on the second half-straight line L2 is larger than that in the natural state, and becomes larger as it goes away from the first rotation axis O1.

Fig. 11 is a plan view showing a constant force spring, a fixing piece, and a fixing ring of the second embodiment. In fig. 11, a torque generation state of the constant force spring 200 is shown.

The constant force spring 200 is in the torque generation state shown in fig. 11 by rotating the inner end portion 202 by a predetermined angle (360 ° in the illustrated example) in the counterclockwise direction from the pre-wind-up state by the torque adjustment mechanism 110 (see fig. 4) and winding up the constant force spring 200. In the torque generating state, the constant force spring 200 extends along a spiral curve that approximates an archimedean curve centered on a position deviated from the first rotation axis O1 to the inner end portion 202 side. In the torque generating state, with respect to the constant force springs 200, adjacent springs are separated from each other to avoid self-contact.

As described above, the constant force spring 200 of the present embodiment is provided with the crank portion 206 that displaces a part of the outermost periphery including the outer end portion 201 to the outside in the radial direction. According to this configuration, the outer end portion 201 of the constant force spring 200 can be provided outside in the radial direction in a natural state, as compared with the case where the constant force spring is not provided with the crank portion. Therefore, in the conventional constant torque mechanism in which the outer end portion of the constant force spring not equipped with the crank portion is mounted at a position in a natural state, the constant force spring 200 equipped with the crank portion 206 is mounted, whereby the outer end portion 201 of the constant force spring 200 can be brought close to the first rotation axis O1. Thus, in the pre-wind-up state, as in the first embodiment, the pitch P1 between the springs on the first half-straight line L1 extending from the first rotation axis O1 to the outer end 201 is narrower than the pitch P2 between the springs on the second half-straight line L2 extending from the first rotation axis O1 to the opposite side to the first half-straight line L1, as viewed in the vertical direction. Therefore, the constant force spring 200 is mounted to the constant torque mechanism formed in such a manner that the constant force spring of the related art is mounted, thereby being capable of stably generating a desired torque.

[ third embodiment ]

Next, a third embodiment will be described with reference to fig. 12 and 13. In the first embodiment, in the natural state of the constant force spring 100 shown in fig. 7, the center of the archimedean curve along the shape of the constant force spring 100 coincides with the central axis X of the fixed ring 304. In contrast, in the third embodiment, in the natural state of the constant force spring 300, the point at which the center Y of the archimedean curve along the shape of the constant force spring 300 is shifted from the central axis X of the fixed ring 304 is different from that of the first embodiment. The configuration other than the configuration described below is the same as that of the first embodiment.

Fig. 12 is a plan view showing a constant force spring, a fixing piece, and a fixing ring of the third embodiment. In fig. 12, the natural state of the constant force spring 300 is shown.

As shown in fig. 12, the constant force spring 300 is equipped with: an outer end portion 301 to which a fixing piece 105 is attached; and an inner end 302 to which a retaining ring 304 is attached. The constant force spring 300 extends along an archimedean curve having a point provided on the opposite side of the center axis X of the fixed ring 304 from the inner end portion 302 as a center Y when viewed in the vertical direction in a natural state. The fixing ring 304 is formed in a ring shape coaxial with the first rotation axis O1. The outer peripheral surface of the fixed ring 304 is formed with a substantially constant outer diameter, and is connected to the inner end portion 302 of the constant force spring 300.

Fig. 13 is a plan view showing a constant force spring, a fixing piece, and a fixing ring of the third embodiment. In fig. 13, a torque generation state of the constant force spring 300 is shown.

In the pre-wind-up state of the constant force spring 300, the outer end portion 301 of the constant force spring 300 is attached to the constant force upper stage wheel 40 via the fixing piece 105 so as to be located in the vicinity of the first rotation axis O1 from the position C in the natural state, as in the first embodiment. The constant force spring 300 is in the torque generation state shown in fig. 13 by rotating the inner end portion 302 by a predetermined angle (360 ° in the illustrated example) in the counterclockwise direction from the pre-wind-up state by the torque adjustment mechanism 110 to wind up the constant force spring 300. In the torque generating state, the constant force spring 300 extends along a spiral curve that approximates an archimedean curve centered on the first rotation axis O1. That is, the constant force spring 300 is disposed concentrically with the fixed ring 304 in the torque generation state.

As described above, in the natural state in which no load is applied to the constant force spring 300, the constant force spring 300 of the present embodiment extends along the archimedean curve, and in the natural state, the center Y of the archimedean curve along the shape of the constant force spring 300 is provided on the opposite side of the inner end portion 302 across the center axis X of the fixed ring 304. According to this configuration, the shape of the constant force spring 300 in the torque generation state can be made to be a spiral curve similar to an archimedean curve. Here, since the innermost peripheral portion of the constant force spring 300 is reduced in diameter if the constant force spring 300 is wound tight, the center of the spiral curve is displaced in a manner adjacent to the inner end portion 302 as the constant force spring 300 is wound tight. Therefore, by providing the center Y of the archimedean curve in the natural state on the opposite side of the inner end portion 302 with respect to the center axis X of the fixed ring 304, the center of the spiral curve is brought close to the first rotation axis O1 in the torque generating state. This makes it possible to uniformly bring the entire innermost peripheral portion of the constant force spring 300 closer to the first rotation axis O1, reduce the gap between the innermost peripheral portion of the constant force spring 300 and the fixed ring 304, and make the interval between the outermost peripheral portion and the innermost peripheral portion of the constant force spring 300 wider as a whole in the circumferential direction. Therefore, the distance between the adjacent springs can be increased, and the springs can be prevented from coming into contact with each other. Thus, the constant force spring 300 is able to generate a desired torque.

[ fourth embodiment ]

Next, a fourth embodiment will be described with reference to fig. 14 to 16. The constant force spring 100 of the first embodiment is elastically deformed so as to be reduced in diameter by tightening the outer end portion 101 in the clockwise direction with respect to the inner end portion 102, thereby generating a torque. In contrast, the constant force spring 400 according to the fourth embodiment is different from the first embodiment in that it elastically deforms so as to expand its diameter by unwinding the outer end portion 401 in the clockwise direction with respect to the inner end portion 402, thereby generating a torque. The configuration other than the configuration described below is the same as that of the first embodiment.

Fig. 14 is a plan view showing a constant force spring, a fixing piece, and a fixing ring of the fourth embodiment. In fig. 14, a natural state of the constant force spring 400 is shown.

As shown in fig. 14, the constant force spring 400 is equipped with: an outer end portion 401 to which the fixing piece 105 is attached; and an inner end 402 to which the retaining ring 104 is attached. The constant force spring 400 is wound by a predetermined winding amount in a counterclockwise direction toward the outer end 401 with the inner end 402 as an unwinding position. In a natural state, the constant force spring 400 extends along an archimedes curve centered on the central axis X of the stationary ring 104. Thereby, the interval between the adjacent springs becomes constant. A preload is applied to the constant force spring 400 by wind-up.

Fig. 15 is a plan view showing a constant force spring, a fixing piece, and a fixing ring of the fourth embodiment. Fig. 15 shows the constant force spring 400 in a state before being wound up.

As shown in fig. 15, the outer end portion 401 of the constant force spring 400 is located at a position farther from the first rotation axis O1 than the position D in the natural state in the pre-wind-up state of the constant force spring 400. The distance between outer end 401 and inner end 402 is greater in the pre-wind-up state than in the natural state. In the present embodiment, the outer end 401 of the constant force spring 400 is disposed on the opposite side of the first rotation axis O1 from the position in the natural state in the pre-wind-up state of the constant force spring 400. Thus, in the constant force spring 400 in the pre-wind-up state, the spacing between the springs adjacent in the radial direction orthogonal to the first rotation axis O1 varies depending on the position in the circumferential direction around the first rotation axis O1.

Specifically, the pitch P1 between the springs on the first half straight line L1 extending from the first rotation axis O1 to the outer end 401 is larger than the pitch between the springs on the second half straight line L2 extending from the first rotation axis O1 to the side opposite to the first half straight line L1 as viewed in the up-down direction. The pitch P1 between the springs on the first half-straight line L1 is larger than the pitch between the springs in the natural state, and becomes larger as it goes away from the first rotation axis O1. The spacing between the springs on the second half-line L2 is smaller than the spacing between the springs in the natural state. In the illustrated example, adjacent springs on the second half-straight line L2 contact each other, and the interval between the springs on the second half-straight line L2 is 0. Further, the adjacent springs may not contact each other on the second half-straight line L2.

Fig. 16 is a plan view showing a constant force spring, a fixing piece, and a fixing ring of the fourth embodiment. In fig. 16, a torque generation state of the constant force spring 400 is shown.

The constant force spring 400 is in a torque generation state shown in fig. 16 by rotating the inner end portion 402 by a predetermined angle (360 ° in the illustrated example) in the counterclockwise direction by the torque adjustment mechanism 110 from the pre-wind-up state and unwinding the constant force spring 400. In the torque generating state, the constant force spring 400 extends along a spiral curve that approximates an archimedean curve centered on a position that is offset to the side opposite from the inner end portion 402 from the first rotation axis O1. In the torque generating state, with respect to the constant force springs 400, adjacent springs are separated from each other to avoid self-contact.

(constant force spring action)

Next, the operation of the constant force spring 400 configured as described above will be described.

If a coil spring such as the constant force spring 400 is wound around an axis by unwinding from a natural state, the diameter is to be enlarged centering on the axis. Therefore, if the spiral spring is wound while keeping the distance between the axis and the outer end and the inner end constant, the spiral spring is deformed by receiving a force in the radial direction from the outer end and the inner end. When the coil spring is unwound from the pre-wind-up state as in the constant force spring 400 of the present embodiment, the entire coil spring is deformed so as to be pressed by the outer end portion, and the pitch between the adjacent springs is wider in the portion on the opposite side of the outer end portion with respect to the axis than in the pre-wind-up state.

According to the present embodiment, the shape of the constant force spring 400 in the torque generation state can be arbitrarily adjusted by appropriately adjusting and changing the pitch between the adjacent springs according to the position in the circumferential direction. Therefore, the distance between the springs is widened due to the deformation caused by the winding of the constant force spring 400, and the outermost peripheral portion of the constant force spring 400 can be prevented from coming into contact with surrounding members. Thus, the reduction of the torque generated by the constant force spring 400 can be suppressed by the frictional force caused by the contact of the constant force spring 400 in the torque generation state. Thus, the constant force spring 400 can generate a desired torque.

The constant force springs 400 are formed so as to generate a torque by unwinding from a pre-wind-up state in which a pitch P1 between the springs on a first half straight line L1 extending from the first rotation axis O1 to the outer end 401 is wider than a pitch P3883 between the springs on a second half straight line L2 extending from the first rotation axis O1 to the opposite side of the first half straight line L1 as viewed in the vertical direction. According to this configuration, if the constant force spring 400 is unwound from the pre-wind-up state, the portion on the opposite side of the first rotation axis O1 from the outer end portion 401 deforms so that the pitch between the springs becomes wider. Therefore, in the pre-wind-up state, the pitch P1 between the springs on the first half straight line L1 extending from the first rotation axis O1 to the outer end 401 is made wider in advance than the pitch between the springs on the second half straight line L2 extending from the first rotation axis O1 to the side opposite to the first half straight line L1, whereby, in the portion on the side opposite to the outer end 401 across the first rotation axis O1, even if the pitch between the springs is made wider, the outermost peripheral portion of the constant force spring 400 can be suppressed from bulging to the outside in the radial direction to a greater extent than the periphery thereof in the portion on the side opposite to the outer end 401 across the first rotation axis O1. Therefore, the outermost peripheral portion of the constant force spring 400 can be suppressed from contacting surrounding components. Therefore, a desired torque can be generated in the constant force spring 400 that generates a torque by unwinding from the pre-wind-up state.

[ fifth embodiment ]

Next, a fifth embodiment will be described with reference to fig. 17 to 19. The timepiece 501 of the fifth embodiment differs from the timepiece 1 of the first embodiment in that it is provided with a reverse movement mechanism 511 for moving the date hand 8. The configuration other than the configuration described below is the same as that of the first embodiment.

Fig. 17 is an external view showing a timepiece of the fifth embodiment.

As shown in fig. 17, a timepiece 501 is provided with a calendar display portion 501a that displays the date. The calendar display 501a includes a date indicator 8 included in the pointer 4 and fan-shaped marks provided on the dial 3. The date hand 8 is provided so as to be rotatable within a predetermined angular range about an axis different from the hour hand 5, minute hand 6, and second hand 7. The fan-shaped scale is constituted by numerals of "1" to "31" indicating dates. The fan-shaped scale is provided in accordance with the rotation range of the date hand 8, and is indicated by the date hand 8.

Fig. 18 and 19 are plan views of the retrograde mechanism.

As shown in fig. 18, movement 510 is equipped with a retrograde mechanism 511 that drives date hand 8. The reversing mechanism 511 reciprocates the date hand 8 within a predetermined angular range. The reversing mechanism 511 is equipped with a day-changing wheel 512, a day-changing transmission wheel 520, a date return hand lever 540, a date hand wheel 550, and a return spring 560.

The day-change wheel 512 is coupled to the power source-side gear train 12 (see fig. 2) described above and rotates once in 1 day (24 hours). A day-change claw 513 is provided on the day-change wheel 512. The date changing claw 513 includes a spring portion 514 formed in an arc shape in a plan view and an abutment portion 515 provided at a tip end of the spring portion 514. The day hand lever 513 is disposed so as to overlap the day hand wheel 512 in a plan view. The day-change claw 513 is provided integrally with the day-change wheel 512, and rotates in synchronization with the day-change wheel 512. The spring portion 514 is elastically deformable in the circumferential direction and the radial direction of the day drive pulley 512. The contact portion 515 rotates about the rotation axis of the day drive pulley 512 in accordance with the rotation of the day drive pulley 512, and thereby engages with the day drive transmission pulley 520 once every 1 degree of rotation to rotate the day drive transmission pulley 520.

The date-changing transmission wheel 520 is formed in a disk shape, and a plurality of teeth 521 are formed on an outer peripheral edge thereof. The plurality of teeth 521 are formed with 31 teeth corresponding to 31 days which is the number of days of 1 month. One of the plurality of teeth 521 is pressed 1 time within 1 day by the abutment portion 515 of the day-changing claw 513 rotated 1 time within 1 day. Thus, the day-change transmission wheel 520 rotates 1 step in 1 day and 1 time in 1 month (i.e., 31 days) at the same angular pitch as the pitch angle of the plurality of teeth 521.

The date operating cam 525 is provided to the date change transmission wheel 520. The date operating cam 525 rotates 1 time in 1 month in synchronization with the day change transmission wheel 520. The outer peripheral surface of the date operating cam 525 is a cam surface 526 formed in a spiral shape with a radius that increases in the direction opposite to the rotation direction of the day-change transmission wheel 520. The cam surface 526 has an outermost portion 526a separated by the greatest distance from the rotational axis of the day changing transfer wheel 520 and an innermost portion 526b separated by the least distance from the rotational axis of the day changing transfer wheel 520.

The date jumper 530 abuts on the date change transmission wheel 520. The date jumper 530 corrects the position of the rotation direction of the date change transmission wheel 520. The date jumper 530 includes an elastically deformable date jumper spring portion 531 whose tip end portion becomes a free end. The tip end portion of the date jumper spring portion 531 can engage with the tooth 521 of the day-shift transmission wheel 520. The date jumper 530 has a tip end portion that engages with the tooth 521 of the day-change transmission wheel 520, thereby correcting the rotation of the day-change transmission wheel 520. Thereby, the day-change transmission wheel 520 can rotate 1 step in 1 day at the same angular pitch as the pitch angle of the plurality of teeth 521.

The date return pin lever 540 is provided so as to be capable of reciprocating rotation about an axis line that is offset from the rotation axis line of the date change transmission wheel 520. The date reset lever 540 is equipped with: a sector gear portion 541 meshed with the date hand wheel 550; and a cam wrist 542 that rotates integrally with the sector gear portion 541. The cam arm portion 542 is a cam follower whose tip end portion abuts against the cam surface 526 of the date operating cam 525. Hereinafter, the position of the date reset lever 540 when the distal end portion of the cam arm 542 abuts on the innermost portion 526b of the cam surface 526 of the date operating cam 525 is referred to as an "initial position". The position of the date returning hand lever 540 when the tip end portion of the cam arm 542 abuts against the outermost portion 526a of the cam surface 526 of the date operating cam 525 is referred to as "final position". As described above, the date operating cam 525 rotates 1 time in 1 month. Thus, the date reset needle lever 540 reciprocates 1 time between the initial position and the final position within 1 month. In fig. 18, the date return pin lever 540 is shown in the initial position. In fig. 19, the date return pin lever 540 is shown in a state of being located at the end position.

The date hand wheel 550 is coupled to the date hand 8 to rotate the date hand 8. The date hand wheel 550 rotates about the rotation axis O3 in synchronization with the rotation of the date return hand lever 540. When the date return lever 540 is at the initial position, the date indicator 550 is rotated to the maximum extent in one direction (counterclockwise in the drawing). At this time, the date hand 8 indicates "1" of the scale of the calendar display portion 501a (see fig. 17). When the date return lever 540 is located at the end position, the date indicator 550 is rotated in the other direction to the maximum extent. At this time, the date hand 8 indicates "31" of the scale of the calendar display portion 501 a. Thus, the date hand 8 moves 1 step every 1 day in accordance with the rotation of the date operating cam 525 and the movement of the date return hand lever 540.

The return spring 560 urges the date return pin lever 540 in a direction to approach the date operation cam 525 via the date pin wheel 550. The return spring 560 is a coil spring formed in the same manner as the constant force spring 100 described above. An inner end portion 562 of the return spring 560 is attached to the date indicator 550 and is fixedly provided to the date indicator 550. An outer end portion 561 of the return spring 560 is attached to a member (for example, the main plate 23 or the like) rotatably supporting the day hand wheel 550.

A preload is applied to the return spring 560 by the wind-up. In the present embodiment, the return spring 560 is elastically deformed to reduce the diameter thereof by winding the inner end portion 562 around the outer end portion 561, thereby generating a torque. In a state where the date return pin lever 540 is at the initial position, the return spring 560 is wound up from the state before winding up. Further, the pre-wind-up state of the return spring 560 is as follows: an outer end 561 of the return spring 560 is attached to the main plate 23, and an inner end 562 of the return spring 560 is attached to the day hand gear 550, and no torque is generated. In the state where the date returning needle lever 540 is located at the final position, the return spring 560 is wound further than the state where the date returning needle lever 540 is located at the initial position. Thus, even in a state where the date returning hand lever 540 is located at any position ranging from the initial position to the final position, the return spring 560 generates a torque and urges the date returning hand lever 540 in a direction approaching the date operating cam 525.

The outer end 561 of the return spring 560 is disposed closer to the rotation axis O3 of the day hand gear 550 than the position in the natural state in the pre-wind-up state of the return spring 560, similarly to the constant force spring 100 shown in fig. 8. The distance between the outer end 561 and the inner end 562 is smaller in the pre-wind-up state than in the natural state. Thus, in the return spring 560 in the pre-wind-up state, the pitch between the springs adjacent in the radial direction orthogonal to the rotation axis O3 varies depending on the position in the circumferential direction around the rotation axis O3.

As shown in fig. 19, in a state where the torque is generated by the wind-up, the return spring 560 extends along a spiral curve that approximates an archimedean curve centered on a position deviated from the rotation axis O3 of the date indicator wheel 550 to the side of the inner end portion 562. Even in a state where the date return pin lever 540 is located at any one position ranging from the initial position to the final position, the return springs 560 are separated from each other so as to avoid self-contact between adjacent springs.

(operation of the reverse mechanism)

Next, the operation of the reversing mechanism 511 configured as described above will be described.

As described above, the day-change wheel 512 rotates 1 time in 1 day. The day-changing claw 513 provided at the day-changing wheel 512 rotates 1 time in 1 day in synchronization with the day-changing wheel 512.

The contact portion 515 of the day-changing pawl 513 contacts the teeth 521 of the day-changing transmission wheel 520 by rotating, and then presses the teeth 521 with the passage of time. The time when the contact portion 515 of the day changing pawl 513 contacts the tooth 521 of the day changing transmission wheel 520 is generally set to a predetermined time (for example, between 23 pm and 0 am on the next day) before 0 am at which the date is changed. Then, if the tooth 521 of the day-change transmission wheel 520 is pressed by the contact portion 515 of the day-change claw 513 and rotated by a predetermined angle, the tip end portion of the date jumper spring portion 531 rides over the tooth 521 and engages with the adjacent tooth 521. Thus, the day change transmission wheel 520 rotates 1 step in 1 day and 1 time in 1 month at a predetermined angular interval.

The date operating cam 525 rotates 1 step in 1 day and 1 time in 1 month in synchronization with the day change transmission wheel 520.

Here, the cam arm 542 is relatively moved from the innermost portion 526b to the outermost portion 526a of the cam surface 526 by the rotation of the date operating cam 525, and thereby the date resetting lever 540 is moved from the initial position to the final position. Thereby, the date hand wheel 550 engaged with the sector gear portion 541 of the date return hand lever 540 rotates 1 step in 1 day. The date hand 8 attached to the date hand wheel 550 moves by 1 day around 0 am of date change in accordance with the rotation of the date hand wheel 550. In this way, retrograde mechanism 511 walks date needle 8 by 1 step from the first day to the last day of a month.

As described above, with the return spring 560 of the present embodiment, in the pre-wind-up state, the pitch between the springs adjacent in the radial direction orthogonal to the rotation axis O3 varies depending on the position in the circumferential direction around the rotation axis O3. With this configuration, the same operational effects as those of the constant force spring 100 according to the first embodiment can be obtained.

Further, since the reverse mechanism 511 of the present embodiment is provided with the return spring 560 that generates a desired torque, it is possible to suppress the torque applied to the day hand wheel 550 from being insufficient. This can prevent the date indicator 8 from being repeatedly moved and disturbed due to insufficient torque applied to the date indicator wheel 550.

[ sixth embodiment ]

Next, a sixth embodiment will be described with reference to fig. 20 to 27. The timepiece 601 of the sixth embodiment differs from the timepiece 1 of the first embodiment in that it is equipped with a calendar mechanism 611 that instantaneously drives the date wheel 9. The configuration other than the configuration described below is the same as that of the first embodiment.

Fig. 20 is an external view showing a timepiece according to a sixth embodiment.

As shown in fig. 20, a timepiece 601 is provided with a calendar display portion 601a that displays the date. The calendar display 601a includes: a date window 3a formed in the dial 3; and a date character 9a displayed on a date wheel 9 described later and clearly indicated through the date window 3 a.

Fig. 21 is a plan view of the calendar mechanism as viewed from below. In fig. 21, a part of a component of the calendar mechanism is broken and shown.

As shown in fig. 21, the movement 610 is equipped with the date wheel 9 described above and a calendar mechanism 611 that instantaneously drives the date wheel 9. The date wheel 9 is an annular member rotatably attached to the main plate 23. The date indicator 9 is displayed with date characters indicating numbers 1 to 31 in order along the circumferential direction (see fig. 20). A plurality of teeth 9b are formed on the inner peripheral surface of the date wheel 9. The plurality of teeth 9b protrude to the inside in the radial direction, and are formed at intervals in the circumferential direction.

The calendar mechanism 611 is mainly equipped with a day-change wheel 612, a day-change wheel restricting spring 690, and a date jumper 695.

The day-change wheel 612 rotates 1 time in 1 day (24 hours) based on the rotation of the hour wheel 20. During normal movement of the movement 610, the day-change wheel 612 rotates about the rotation axis O4 in the direction of arrow a in the drawing. Hereinafter, the rotation direction of the day changing wheel 612 during normal needle feed is referred to as a normal rotation direction. The rotation of the hour wheel 20 is transmitted to the day change wheel 612 via the first and second day change

intermediate wheels

613 and 614 that are meshed with each other. The day-changing wheel 612 is provided with: a day-change gear 620 that rotates 1 time in 1 day in synchronization with the rotation of the hour wheel 20; a day-change pawl unit 630 provided rotatably about a rotation axis O4 with respect to the day-change gear 620; and a day-change work spring 680 (see fig. 23) that applies torque between the day-change gear 620 and the day-change pawl unit 630.

Fig. 22 is a plan view of the day-change wheel as viewed from below. Fig. 23 is a plan view of the day-change wheel as viewed from above. Fig. 24 is a sectional view taken along line XXIV-XXIV of fig. 22. In fig. 22, a part of the day-shift wheel is broken.

As shown in fig. 23 and 24, the sun gear 620 is equipped with: a gear main body 621 that meshes with the second day change intermediate wheel 614 (see fig. 21); and a spring pin 622 supported to the gear body 621. The gear main body 621 is provided rotatably about a rotation axis O4. A through hole through which a date change core 631 described later is inserted is formed in the center of the gear main body 621. The spring pin 622 is supported by the gear main body 621 at a position eccentric with respect to the rotation axis O4. Thereby, the spring pin 622 revolves around the rotation axis O4 in synchronization with the rotation of the gear main body 621. The spring pin 622 is equipped with: a shaft portion 623 fixed to the gear main body 621; and a flange portion 624 that protrudes outward in the radial direction from the shaft portion 623. The shaft portion 623 protrudes upward from the gear main body 621. The flange portion 624 is formed in a disk shape. The flange portion 624 is provided at the middle portion in the vertical direction of the shaft portion 623.

As shown in fig. 22 and 24, the day-change pawl unit 630 is equipped with a day-change core 631, a day-change pawl 640, a day-change pawl spring 650, a pawl pressing piece 660, and a spring pressing piece 670.

As shown in fig. 24, the day change core 631 is equipped with: a center pipe 632 provided coaxially with the gear main body 621 of the sun gear 620; and a pawl mount 633 extending from the center tube 632. The center pipe 632 is inserted into a through hole penetrating the gear main body 621 so as to be relatively rotatable. The center pipe 632 protrudes to the upper and lower sides with respect to the gear main body 621. The pawl holder 633 is disposed so as to overlap the lower surface of the gear main body 621. The claw seat 633 is formed in an annular shape protruding to the outside in the radial direction from the center tube 632 and extending along the circumferential direction over the entire circumference.

As shown in fig. 22, the day-changing claw 640 is arranged so as to overlap with the lower surface of the claw seat 633. The day-changing claw 640 is disposed along the outer peripheral edge of the claw holder 633 as viewed in the vertical direction. The day-changing claw 640 is rotatably supported by the claw seat 633 in an intermediate portion in the circumferential direction around the rotation axis O4. Specifically, the day-changing claw 640 is rotatably supported by a pin protruding downward from the claw holder 633. The day-changing claw 640 is equipped with: a pawl main body 641 extending from the rotation center in the normal rotation direction of the day changing wheel 612; and an arm 642 extending from the rotation center in the reverse direction of the day-change wheel 612. The arm 642 is formed so as to be able to contact the outer peripheral surface of the center tube 632 of the day-changing core 631. The distal end 641a of the pawl body 641 is formed so as to protrude outward in the radial direction from the pawl holder 633 when viewed in the vertical direction. The state in which the tip end portion 641a of the pawl body 641 protrudes to the maximum extent from the pawl holder 633 is a state in which the arm 642 is in contact with the outer peripheral surface of the center tube 632 of the day service core 631. That is, the arm 642 restricts the range in which the pawl body 641 protrudes from the pawl holder 633.

The pawl body 641 is provided with: an engagement surface 641b facing the forward rotation direction of the day-changing wheel 612; and a sliding contact surface 641c facing the side opposite to the rotation axis O4 side. The engagement surface 641b extends from the distal end 641a of the pawl main body 641 to the rotation axis O4 side. The slide contact surface 641c extends from the tip end portion 641a of the pawl main body 641 in the reverse direction of the day index 612 and to the rotation axis O4 side in a gently inclined state with respect to the circumferential direction around the rotation axis O4. The pawl body 641 is disposed at the following positions: when the day-shift claw unit 630 rotates in the normal rotation direction, the engagement surface 641b can contact the tooth portion 9b of the date indicator 9 (see also fig. 21). When the day-changing claw unit 630 rotates in the reverse rotation direction, the sliding contact surface 641c contacts the tooth portion 9b of the date wheel 9, and the claw body 641 is thereby displaced inward in the radial direction.

The day-change claw spring 650 applies force to the day-change claw 640. The day-changing claw spring 650 is disposed so as to overlap the lower surface of the claw base 633. The day-changing pawl spring 650 is equipped with: a base 651; fixedly supported to the claw mount 633; and a spring main body 652 that extends from the base portion 651 in the normal rotation direction of the day-changing wheel 612, and that contacts the arm 642 of the day-changing claw 640. The base 651 is supported by a pin projecting downward from the pawl seat 633. The spring main body 652 is in contact with the arm 642 of the day-changing claw 640 from the outside in the radial direction. The spring main body 652 presses the arm 642 to the inside in the radial direction by the restoring force of the elastic deformation. Thereby, the day-change claw 640 is biased in the direction in which the arm 642 comes into contact with the outer peripheral surface of the center tube 632 of the day-change core 631. That is, the day-changing pawl 640 is biased in a direction in which the distal end portion 641a of the pawl body 641 protrudes outward in the radial direction from the pawl holder 633 as viewed in the vertical direction.

The claw pressing member 660 restricts downward movement of the day-changing claw 640 and the day-changing claw spring 650. The claw holder 660 is disposed on the side opposite to the claw seat 633 with the day-changing claw 640 and the day-changing claw spring 650 therebetween. Further, a gap may be provided between the claw holder 660 and the day-changing claw 640 and the day-changing claw spring 650. The claw pressing member 660 is formed in a disk shape having substantially the same diameter as the outer diameter of the claw seat 633, and is disposed coaxially with the claw seat 633. A through hole into which the lower end portion of the center tube 632 of the date changing core 631 is inserted is formed in the center of the pawl holder 660. Further, the claw holder 660 has a through hole into which a pin protruding from the claw seat 633 is inserted. The claw pressing piece 660 is fixedly provided to the date changing core 631.

As shown in fig. 23, the spring pressing piece 670 holds the day-changing operation spring 680 between the gear main body 621 of the day-changing gear 620. The spring retainer 670 is disposed above the gear body 621 of the sun gear 620. The spring presser 670 is formed in a disk shape having a smaller diameter than the gear main body 621 of the day gear 620, and is disposed coaxially with the gear main body 621 of the day gear 620. A through hole into which the upper end portion of the center tube 632 of the date change core 631 is inserted is formed in the center of the spring holder 670. The spring pressing piece 670 is fixedly provided to the date change core 631.

The spring presser 670 has a spring pin guide hole 671 and a restricting spring engagement portion 672. The spring pin guide hole 671 is inserted into an upper end portion of the shaft portion 623 of the spring pin 622 in the day-change gear 620. The spring pin guide hole 671 extends in an arc shape around the rotation axis O4 to allow displacement of the spring pin 622 around the rotation axis O4. The spring pin guide hole 671 is equipped with a downstream end 671a disposed in the forward rotation direction of the day drive wheel 612 and an upstream end 671b disposed in the reverse rotation direction of the day drive wheel 612. The restricting spring engaging portion 672 is a notch formed in the outer peripheral surface of the spring presser 670. The restricting spring engagement portion 672 is formed in the vicinity of the downstream end 671a of the spring pin guide hole 671. The restricting spring engagement portion 672 is provided with a spring engagement surface 672a facing the normal rotation direction of the day drive wheel 612. In a state where the upper end portion of the shaft portion 623 of the spring pin 622 is located at the downstream end 671a of the spring pin guide hole 671, the spring engagement surface 672a is provided at a position where the flange portion 624 of the spring pin 622 overlaps, as viewed in the vertical direction.

As shown in fig. 23 and 24, the day-changing work spring 680 is disposed between the gear body 621 of the day-changing gear 620 and the spring pressing piece 670 of the day-changing pawl unit 630. The birthday operation spring 680 is a coil spring formed in the same manner as the constant force spring 100 described above. An inner end 682 of the date changing work spring 680 is attached to the date changing claw unit 630. Specifically, inner end portion 682 of holiday operation spring 680 is fixedly supported by holiday core 631 via annular fixing ring 684 externally fitted to center tube 632 of holiday core 631. The fixing ring 684 is disposed between the gear main body 621 of the sun gear 620 and the spring presser 670. The outer end 681 of the day drive spring 680 is attached to the day drive gear 620. Specifically, an outer end 681 of the date changing spring 680 is supported by the spring pin 622 via an annular fixing piece 685 which is externally inserted to the shaft portion 623 of the spring pin 622. The fixing piece 685 is disposed between the gear body 621 of the sun gear 620 and the flange portion 624 of the spring pin 622. In the present embodiment, the date change spring 680 is elastically deformed to reduce its diameter by tightening the inner end 682 with respect to the outer end 681, thereby generating torque.

As shown in fig. 23, in a state where the relative torque is not applied from the outside between the day changing gear 620 and the day changing claw unit 630, the day changing operation spring 680 is attached to the day changing gear 620 and the day changing claw unit 630 in such a manner that the spring pin 622 is located near the upstream end 671b of the spring pin guide hole 671. The sun gear spring 680 is wound up as the outer end 681 moves in the normal rotation direction of the sun gear 612 relative to the inner end 682, and causes the inner end 682 to generate a torque in the normal rotation direction of the sun gear 612. Thereby, the date changing operation spring 680 urges the date changing claw unit 630 in the normal rotation direction of the date changing wheel 612.

The outer end 681 of the day-change operation spring 680 is disposed closer to the rotation axis O4 than the position in the natural state in the pre-wind-up state of the day-change operation spring 680, similarly to the constant force spring 100 shown in fig. 8. Further, the pre-wind-up state of the weekday operation spring 680 is as follows: an outer end 681 of the day drive spring 680 is attached to the day drive gear 620, and an inner end 682 of the day drive spring 680 is attached to the day drive pawl unit 630, and no torque is generated. The distance between the outer end 681 and the inner end 682 is smaller in the pre-wind-up state than in the natural state. Thus, in the holiday work spring 680 in the pre-wind-up state, the spacing between the springs adjacent in the radial direction orthogonal to the rotation axis O4 varies depending on the position in the circumferential direction around the rotation axis O4.

The holiday activation spring 680, not shown, extends along a spiral curve that approximates an archimedean curve centered on a position offset from the rotation axis O4 to the side of the inner end portion 682 in a state where torque is generated by winding up. Even in a state where the spring pin 622 is located at any one of the spring pin guide holes 671, with respect to the spring 680 for the weekday operation, the adjacent springs are separated from each other to avoid self-contact.

As shown in fig. 21, the day change wheel regulating spring 690 is formed in a cantilever lever shape. A base end portion of the date indicator regulating spring 690 is fixedly provided to the main plate 23 and the like. The tip 690a of the day drive regulating spring 690 is provided so as to be able to slide on the outer peripheral surface of the spring retainer 670. The tip 690a of the day drive regulating spring 690 faces in the reverse direction of the day drive 612. The tip end portion 690a of the date indicator regulating spring 690 engages with the spring engaging surface 672a of the regulating spring engaging portion 672 of the spring pusher 670. The day drive pulley regulating spring 690 is formed so that the flange portion 624 of the spring pin 622 of the day drive gear 620 can contact the tip end portion 690a in a state where the tip end portion 690a is engaged with the regulating spring engaging portion 672 of the spring holder 670.

The date jumper 695 corrects the position of the date wheel 9 in the rotation direction. The date jumper 695 includes an elastically deformable date jumper spring portion 696 whose tip end portion becomes a free end. The tip end portion of the date jumper spring portion 696 can engage with the tooth portion 9b of the date wheel 9. The date jumper 695 has a tip end portion engaged with the tooth portion 9b of the date indicator 9, thereby correcting the rotation of the date indicator 9. Thereby, the date indicator 9 can be rotated 1 step in 1 day at the same angular pitch as the pitch angle of the plurality of tooth portions 9 b.

(action of calendar mechanism)

Next, the operation of the calendar mechanism 611 configured as described above will be described with reference to fig. 21 and fig. 25 to 27.

Fig. 25 to 27 are explanatory views of the operation of the calendar mechanism, and are plan views of a part of the calendar mechanism as viewed from below.

As described above, the day change gear 620 of the day change wheel 612 rotates 1 time in the normal rotation direction within 1 day in synchronization with the rotation of the hour wheel 20. Since if the sun gear 620 rotates in the normal rotation direction, the rotational force thereof is transmitted to the day-changing pawl unit 630 via the day-changing work spring 680, the day-changing pawl unit 630 also rotates in the normal rotation direction.

As shown in fig. 21, if the rotation of the day shift claw unit 630 is continued, the tip end portion 690a of the day shift wheel regulating spring 690 engages with the regulating spring engaging portion 672 of the spring presser 670 for 1 rotation every 1 degree. This restricts the rotation of the day-shift claw unit 630 in the normal rotation direction. Therefore, the day-change gear 620 rotates in the normal rotation direction with respect to the day-change pawl unit 630. At this time, the day-change gear 620 rotates the shaft portion 623 of the spring pin 622 while moving in the normal rotation direction from the vicinity of the upstream end 671b (see fig. 23) of the spring pin guide hole 671 of the day-change claw unit 630. The date changing gear 620 winds up the date changing operation spring 680 and rotates in the normal direction. As a result, the date-changing operating spring 680 winds up while increasing the torque that urges the date-changing claw unit 630 in the normal rotation direction.

Then, as shown in fig. 25, if the rotation of the day changing gear 620 is further continued, the shaft portion 623 of the spring pin 622 reaches the vicinity of the downstream end 671a (refer to fig. 23) of the spring pin guide hole 671. Then, the flange portion 624 of the spring pin 622 contacts the tip end portion 690a of the day drive regulating spring 690, and presses the tip end portion 690a of the day drive regulating spring 690 outward in the radial direction. Then, the engagement between the date indicator changing wheel regulating spring 690 and the regulating spring engaging portion 672 of the spring presser 670 is released. The day hand gear 612 is designed to release the engagement between the day hand gear regulating spring 690 and the regulating spring engaging portion 672 of the spring presser 670 at 0 am.

As a result, the wound-up day-change operation spring 680 is unwound at one stroke, and the day-change claw unit 630 is rapidly rotated in the normal rotation direction. Then, as shown in fig. 26, the claw body 641 of the day-changing claw 640 moves sharply in the normal rotation direction of the day-changing wheel 612, and the engagement surface 612b comes into contact with the tooth portion 9b of the date wheel 9, thereby rotating the date wheel 9. This allows the date indicator 9 to be instantaneously rotated while releasing the engagement by the date jumper spring part 696.

Then, as shown in fig. 27, if the date indicator 9 is rotated, the tip end portion of the date jumper spring portion 696 engages with the next tooth portion 9b of the date indicator 9 again. Thereby, the position of the date wheel 9 in the rotational direction is corrected again. As a result, the date indicated in the date window 3a of the dial 3 can be instantaneously switched by 1 day.

As described above, with the day-change work spring 680 of the present embodiment, in the pre-wind-up state, the pitch between the springs adjacent in the radial direction orthogonal to the rotation axis O4 changes depending on the position in the circumferential direction around the rotation axis O4. With this configuration, the same operational effects as those of the constant force spring 100 according to the first embodiment can be obtained.

Further, since the calendar mechanism 611 of the present embodiment is provided with the date change operating spring 680 that generates a desired torque, it is possible to suppress a shortage of torque applied between the date change gear 620 and the date change claw unit 630. This can suppress the shortage of the rotational force transmitted to the date indicator 9 due to the shortage of the torque applied to the day-shift claw unit 630. Therefore, the calendar mechanism 611 can perform a reliable day-to-day operation.

In the present embodiment, the date wheel 9 displays a number corresponding to the date as the date character 9a, but the present invention is not limited thereto. The day wheel 9 may display the day as a date letter.

The present invention is not limited to the above-described embodiments described with reference to the drawings, and various modifications are considered within the technical scope thereof.

For example, in the above embodiments, the constant force springs 100, 200, 300, 400 extend along the archimedean curve in the natural state. However, the constant force springs are not limited to this, and may be formed such that the pitch between adjacent springs becomes narrower toward the outer side in the radial direction in a natural state, or may be formed such that the pitch between adjacent springs becomes wider toward the outer side in the radial direction in a natural state.

In the second embodiment, the configuration in which the constant force spring 200 has the crank portion 206 and the outer end portion 201 is displaced outward in the radial direction has been described. Similarly, for example, in the constant force spring 400 according to the fourth embodiment, the outer end portion may be moved inward in the radial direction by the crank portion. Thus, by mounting the constant force spring provided with the crank portion to the conventional constant torque mechanism in which the outer end portion of the constant force spring not provided with the crank portion is mounted at a position in a natural state, the outer end portion of the constant force spring can be disposed at a position separated from the first rotation axis O1.

In the above-described embodiment, the case where the coil spring of the present invention is used as the constant force spring of the constant torque mechanism 30 has been described as an example, but the present invention is not limited thereto. For example, the spiral spring of the present invention can also be applied to a balance spring.

It is to be noted that the components in the above embodiments may be replaced with well-known components without departing from the scope of the present invention, and the above embodiments may be combined as appropriate. For example, a coil spring similar to the constant force spring according to any one of the second to fourth embodiments may be combined with the reverse mechanism 511 according to the fifth embodiment or the calendar mechanism 611 according to the sixth embodiment.

Description of the symbols

1. 501, 601 … … clock 3 … … dial 3a … … date window 8 … … date hand (pointer) 9 … … date wheel 9a … … date word 9b … …

tooth

10, 510, 610 … … movement (movement for clock) 11 … … barrel wheel (power source) 14 … … escaper 23 … … main plate (support, second part) 30 … … constant torque mechanism (torque generating device) 40 … … constant force upper wheel (input rotating body) 45 … … planetary gear (period control mechanism) 47 … … carrier (first part) 60 … … constant force lower wheel (output rotating body) 61 … … constant force lower cylinder (second part) 86 … … engaging fork tile (period control mechanism) 100, 200, 300, 400 … … constant force spring (spiral spring) 101, 201, 301, 401 … …

outer end

102, and, 202. 302, 402 … … inner end 511 … … reverse travel mechanism (torque generating device) 550 … … date hand wheel (rotating part, first part) 560 … … return spring (spiral spring) 561 … … outer end 562 … … inner end 611 … … calendar mechanism 620 … … day-changing gear 622 … … spring pin (first part) 630 … … day-changing claw unit 631 … … day-changing core (second part) 640 … … day-changing claw 680 … … day-changing working spring (spiral spring) 681 … … outer end 682 … … inner end L1 … … first half straight line L2 … … second half straight line O1 … … first rotation axis (axis) O3 … … rotation axis (axis) O4 … … rotation axis (axis).

Claims

1. A coil spring for a timepiece that generates torque by being wound around an axis, characterized by being provided with:

an outer end portion mounted to the first member; and

an inner end portion mounted to the second member,

the outer end portion is attached to the first member, and the inner end portion is attached to the second member, and, in a pre-wind-up state in which no torque is generated, a pitch between springs adjacent in a radial direction orthogonal to the axis varies depending on a position in a circumferential direction around the axis,

the spiral spring is formed in such a manner that a torque is generated by winding from the pre-wind-up state,

in the pre-wind-up state, the pitch on a first half straight line extending from the axis to the outer end portion is narrower than the pitch on a second half straight line extending from the axis to a side opposite to the first half straight line as viewed in the axial direction of the axis, and in a state where torque is generated by the wind-up, the spiral spring extends along a spiral curve that approximates an archimedean curve centered on a position that is offset from the axis to the inner end portion side, and adjacent springs are configured to be separated from each other so as to avoid self-contact.

2. A coil spring for a timepiece that generates torque by being wound around an axis, characterized by being provided with:

an outer end portion mounted to the first member; and

an inner end portion mounted to the second member,

the coil spring is formed so as to generate a torque by unwinding from the pre-wind-up state,

in the pre-wind-up state, the pitch on a first half straight line extending from the axis to the outer end portion is wider than the pitch on a second half straight line extending from the axis to a side opposite to the first half straight line as viewed in the axial direction of the axis, and in a state where a torque is generated by the unwinding, the spiral spring extends along a spiral curve that approximates an archimedean curve centered on a position offset from the axis to a side opposite to the inner end portion, and adjacent springs are configured to be separated from each other so as to avoid self-contact.

3. The helical spring as claimed in claim 1 or claim 2,

at least a portion of the coil spring extends along an archimedean curve in a state in which a load is not applied to the coil spring.

4. The helical spring as set forth in claim 1,

at least a portion of the coil spring extends along an archimedean curve in a state where a load is not applied to the coil spring,

the center of the archimedean curve is disposed on the opposite side of the axis to the inner end portion.

5. A torque-generating device equipped with:

the helical spring according to any one of claims 1 to 4;

the first member to which either one of the outer end portion and the inner end portion of the spiral spring is attached; and

and the second member to which the other of the outer end portion and the inner end portion of the coil spring is attached.

6. The torque-generative device as claimed in claim 5,

the constant torque mechanism is provided with:

an input rotating body including the first member, rotated by power from a power source, and supplementing power to the spiral spring;

an output rotating body including the second member, rotated by power from the coil spring, and transmitting the power of the coil spring to an actuator; and

and a cycle control mechanism that intermittently rotates the input rotating body with respect to the output rotating body based on rotation of the output rotating body.

7. The torque-generative device as claimed in claim 5,

a reverse mechanism for reciprocating a hand between an initial position and a final position, comprising:

a rotating portion including the first member and rotating in synchronization with the pointer; and

a support portion that includes the second member and rotatably supports the rotating portion.

8. The torque-generative device as claimed in claim 5,

a calendar mechanism for switching a date character indicated in a date window of a dial includes:

a day-change gear including the first member and rotating in synchronization with rotation of the hour wheel; and

and a day-change pawl unit having the second member and a day-change pawl provided on a tooth portion of a date wheel displaying the date characters so as to be engageable and disengageable, and provided so as to be rotatable coaxially with the day-change gear with respect to the day-change gear.

9. Movement for a timepiece, characterized by being equipped with a torque-generating device according to any one of claims 5 to 8.

10. Timepiece, characterized by being equipped with a movement for a timepiece according to claim 9.