JPH01199189A - Sweep operation clock - Google Patents

Abstract

PURPOSE:To reduce an indication slippage and to enable the execution of reliable driving, by setting CXS>K when the number of times of drives of a driving element per 1sec is denoted by S, an attenuation coefficient of a load torque by C and a spring constant by K. CONSTITUTION:A total moment of inertia I based on the fourth wheel 9, positioned to the second hand 10 side from a hair spring 6c is about 0.02 mgmms<2>/rad, an attenuation coefficient C is about 800mgmms/rad, and a spring constant K of the spring 6c is about 220mgmm/rad. When it is assumed that a position of indication of the second hand 10, i.e. the rotational angle of the fourth wheel 9, is theta, an equation of motion Itheta+Ctheta+Ktheta=0 is established. The equation of motion can be solved when the conditions that a main drive wheel 6a rotates at a step of 0.25sec and about 3rpm and that the speed and the position do not change before and after a stepping drive. I is neglected since it is small in comparison with C and K. C/K=t is a time for producing an angular slippage. Accordingly, CXS/K=tXS=N by multiplying same by the number of steps S whereat a driving element makes an intermittent motion for 1sec. Herein CXS>K is necessary, since N of N steps >1.

Description

[Detailed description of the invention]

[Industrial Field of Application] The present invention relates to the relationship between the number of times a drive unit of a sweep hand movement timepiece is driven per second, the damping coefficient of a load mechanism, and the spring constant of a joint mechanism. [Prior Art] As described in Japanese Patent Application Laid-open No. 50-74458, a sweep hand movement timepiece using a magnetic coupling mechanism using a viscous body has been known.

[Problem to be solved by the invention] However, the moment of inertia around the second hand Imgmms”/
rad, damping coefficient of the load mechanism Cmgmms/ra
d, spring constant of the joint mechanism K m g m m / r
ad and the indicated position θrad of the second hand is θ+Cθ.
The relationship θ=0 holds true for +, and the smoothness of hand movement is determined by the condition that the drive side of the joint mechanism periodically rotates due to S times/S movement of the drive unit and the condition of continuity, so ■, C , and S must be set to appropriate values. The greater the number of drives per second S of the drive unit, the greater the reduction ratio from the drive unit to the joint mechanism, and the smaller the angle at which the joint mechanism rotates during one drive cycle of the drive unit, the smaller the amount of torque fluctuation. This increases the smoothness of the second hand movement. The larger the moment of inertia, the larger the inertia torque, so the stability against fluctuations in load torque and restoring torque is high, and the second hand moves smoothly. However, for starting after adjustment, the smaller the moment of inertia, the better.
The second hand can be started immediately. Furthermore, when subjected to an impact, if the moment of inertia is large, the second hand may be misaligned, and although a magnetic joint will not be destroyed, a joint mechanism using a spring connection may be destroyed. At this time, the load mechanism acts as a damper against the impact and attempts to stop the second hand from rotating, so it is desirable that the damping coefficient be large with respect to the moment of inertia.The moment of inertia of the second hand of a normal step movement watch is 0.01/ mgmm
It is approximately s2/rad, and from the design point of view, it is difficult to increase the moment of inertia in a thin and small watch. When the moment of inertia is constant, the relationship between the damping coefficient C and the spring constant is such that the smaller the spring constant K is, the smaller the proportion of fluctuations in restoring torque due to stepwise movements on the drive side of the joint mechanism, and the damping coefficient The larger C is, the smaller the variation ratio of the restoring torque to the load torque becomes, so the rotation of the second hand becomes smoother. However, increasing the damping coefficient increases the load torque, which naturally requires increasing the output torque of the motor, which increases current consumption and requires a larger battery size, which is an obstacle to making watches smaller and thinner. Become. Also, in order to reduce the spring constant, in the case of magnetic joints, the phase difference between the driving side magnet and the driven magnet must be within 90 degrees, otherwise the magnetic force of the driving side and driven side magnets will decrease and the phase will be 18°.
There is a limit because there is a risk that it will shift by 0°. In addition, in the case of a joint mechanism using a spring connection, even if a hairspring with an extremely small spring constant, such as those used in mechanical watches, is used, a considerable amount of space is required, which is an obstacle to making watches smaller and thinner. The present invention is intended to solve these problems, and its purpose is to improve the damping coefficient of the load mechanism, the restoring torque of the joint mechanism, and the number of drives per second of the drive unit in order to smooth the movement of the second hand. It provides the relationship between [Means for Solving the Problems] The sweep hand movement timepiece of the present invention has a second hand, a drive unit that moves intermittently S times per second, a restoring torque that increases with an increase in phase difference, and a spring constant of the restoring torque. Kmgmm/rad joint mechanism, the load torque increases as the angular velocity increases, and the damping coefficient of the load torque becomes Cm g m m s / r
A sweep hand movement timepiece composed of a load mechanism of a and d is characterized in that C×S>K, and S is 1 or more. [Embodiments] Examples of the present invention will be described below based on the drawings. 1 and 2 are cross-sectional views showing one embodiment of the present invention. 1 is the base plate. The step motor, which is a driving part, includes a stator 2, a coil block 3, and a rotor 4.
As a result, the rotor 4 rotates 180° four times per second. The rotation of the rotor 4 is transmitted to the conversion wheel 6 via the fifth wheel & pinion 5. The main drive vehicle 6a and the driven vehicle 6b have a balance spring 6C.
In this embodiment, which has a structure in which a force acts to reduce the mutual phase difference, a torque of about 30 mgmm is generated per 1 rad of mutual phase difference. Further, the rotation speed of the conversion wheel 6 is about 3 rpm. The intermediate wheel 7 meshes with the driven wheel 6b, the oil rotor pinion 8a, and the fourth wheel & pinion 9. A second hand 10 is fixed to the fourth wheel 9, and a minute hand 12 is fixed to the fifth wheel 11. The fifth wheel & pinion 11 consists of a second pinion lla and a second gear 11b, which slip when a certain amount of torque is applied to each other. The fourth wheel & pinion 9 rotates at lrpm, and the speed increasing ratio between the oil rotor pinion 8a and the fourth wheel & pinion 9 is approximately 2.1, so the rotational speed of the oil rotor 8 is approximately 2.1 rpm. lrpm. The number of rotations of rotor 4 is 12
Since the speed is 0 rpm, the reduction ratio between the rotor 4 and the oil rotor 8 is approximately 57. Oil rotor 8 is oil rotor 8a
, an oil rotor stem 8b and an oil rotor plate 8C, and the oil rotor plate 8C rotates in parallel with the cavity 13 and the cap 14. The cavity 13 is filled with silicone oil 15, and when the oil rotor 8 rotates, a load torque proportional to the angular velocity is generated due to viscous friction. This load torque is applied to the oil rotor 8 by 2.
The gaps between the oil rotor plate 8C, the cavity 13, and the cap 14, and the viscosity coefficient of the silicone oil 15 are set so that when rotated at 1 rpm, the viscosity coefficient is about 40 mgmm at 25°C. Since the cap 14 and the yoke 18 are made of high magnetic permeability material, and the oil rotor stem 8b is made of carbon steel, the magnetic flux generated by the magnet 17 forms a magnetic circuit passing through the yoke 16, the oil rotor stem 8b, and the cap 14. A magnetic fluid 18 is placed in the gap between the oil rotor stem 8b and the cap 14.
is attracted, and the silicone oil 1 inside the cavity 13
5 is prevented from leaking from the void. In addition, the cavity 13 is made of engineering plastic to prevent leakage of the silicone oil 15 from the gap between the outer periphery of the cap 14 and the cavity 13, and is made of a material with a relatively small coefficient of thermal expansion. This prevents leakage due to loss of tightness due to the difference in thermal expansion coefficient with the cap 14 at high temperatures. Further, the center hole of the cap 14 is a burring, and the magnetic fluid 18
It has become a gathering place for people. The stepwise rotation of the rotor 4 is transmitted to the main drive wheel 6a via the fifth wheel & pinion 5. The driven wheel 6b is a hairspring 6
Since the torque stored in the rotor c and the load torque of the oil rotor 8 are balanced, the rotor rotates, so it starts slowly at first. Due to the difference in the rotational speed between the main driving wheel 6a and the driven wheel 6b, the torque stored in the balance spring 6c increases, and the rotational speed of the driven wheel 6b increases until it reaches the same rotational speed as the main driving wheel 6a, 3 rpm, and then rotates at a constant speed. becomes. At this time, the driven vehicle 6b is hoisted up by approximately 1 rad relative to the main vehicle 6a, and by approximately 30 m.
gmm restoring torque is working. Here, due to the step drive of the main drive wheel 6a, the torque possessed by the balance spring 6c changes before and after one winding, but the load torque of the oil rotor 8 changes in proportion to the angular velocity, so the torque retained by the hairspring 6c changes in proportion to the angular velocity. If the torque increases and the oil rotor 8 is to be rotated faster, the angular velocity increases, and as a result, the viscous load increases, which prevents the angular velocity from increasing. Conversely, when the angular velocity decreases, the viscous load decreases, so the angular velocity is increased, so that the oil rotor 8 can rotate at a substantially constant speed. In this embodiment, the conversion wheel 6 and the oil rotor 8 are placed off the center of the watch body and laid out in a two-dimensional manner with an intermediate wheel 7 interposed therebetween. Therefore, by lengthening the hairspring 6C, the spring constant is reduced, and by winding the main drive wheel 6a in one step, fluctuations in the restoring force are reduced, and the oil rotor 8 can be rotated at a nearly constant speed. In this example, the thickness of the hairspring is approximately 0.02a++n.
, width approx. 0.08mm, length approx. 60mm, number of turns approx. 10,
The outer diameter is set to 2.7+n+n. Further, in this embodiment, the diameter of the oil rotor plate 8C is about 3 parts, and the gap between the oil rotor plate 8C and the cavity or cap is about 0.18 mm. The gap between the cavity 13, the cap 14, and the oil rotor plate 8c can be widened under load, and the oil rotor plate 8c, the cavity 13, and
The movement of the second hand 10 can be made smoother than 0 or more, which reduces fluctuations in the load caused by the inclination of the cap 14, etc., and allows a stable load to be obtained. The higher the viscosity of the viscous fluid, the more compact it can be, but it is difficult to assemble and the cycle time increases, so
It needs to be in the range of 00,000 cst. FIG. 7 is a plan view of another embodiment showing the action of the regulating lever when the present invention is applied to an electronic timepiece, and shows the regulating lever 1.
9 stops the rotation by coming into contact with the fourth wheel & pinion 9, mechanically regulating it and electrically resetting it. Further, in addition to the intermediate wheel 7, an oil rotor intermediate wheel 18 is provided to further improve layout flexibility. 1 is a main plate 3 which is a coil block that generates a magnetic field, and is connected to a driven wheel 6b via a fifth wheel 5 by a balance spring 6c to drive the rotor 4, and is rotatable coaxially with the driven wheel 6a. A fourth wheel and a pinion equipped with a pointer are driven via an intermediate wheel 7, and an oil rotor 8, which is a load mechanism, is driven via an oil rotor intermediate wheel 18. Reference numeral 23 is a minute wheel for driving the clock, and reference numeral 24 is a small iron wheel in which a stopper wheel 37 is engaged by the operation of a winding stem 32 through the action of a pusher 31 and a bolt 30, making it possible to adjust the clock and minute hand. . 25 is the third wheel that decelerates the movement of the fourth wheel with which the second hand engages and drives the minute hand; 33 is 1, C13, which has a clock circuit;
5 is a crystal oscillator; C33 and the crystal oscillator 35 supply a driving waveform for moving the rotor 5 of the stepping motor to the coil 1 via the circuit board 34. 36 is a battery. Here, 41 is the rotation center of the regulation lever 19, and 40 is the battery 3.
1 on the circuit board by conducting to the positive side of 6. C
This is a reset terminal for resetting the coil block 33, stopping the supply of current to the coil block 3, and stopping the rotation of the rotor 4. 3
Reference numeral 9a denotes a projection portion 19a that connects the positive side of the battery 36 and the circuit holding plate 39 and connects the regulation lever to the positive side via the oshidori bottle 31a, the oshidori 31, and the guide dowel 31b;
19b is a contact that contacts the reset terminal 40, and 19b is a regulating portion that contacts the fourth wheel and stops rotation. In the adjustment operation, by pulling the winding stem 32 in the direction of the arrow, the guide dowel 31b of the adjustment lever rotates the adjustment lever 19 around the rotation center 41 via the guide groove 19c of the adjustment lever, and the adjustment part 19b
and move contact 19a. When setting the hands, the regulating lever 19 regulates the fourth wheel & pinion 9 and at the same time contacts the contact point 19a on the circuit board.
．． Since the output of the X drive pulse from C is stopped and the rotation of the rotor 4 is stopped, the hairspring will not be over-wound or unwound. Approximately 30mgmm, oil rotor 8 is approximately 2. The hairspring 6C has a torque of about 30mgmm when rotating at lrpm, and the reduction ratio of the rotor 4 and conversion wheel 6 is about 40, so the hairspring 6C is regulated by the pulling torque of the rotor 4 and stator 3 and the regulation lever 19. The previous winding angle is maintained. If the regulation is released in this state, the driven wheel 6b can immediately rotate at a constant speed. FIG. 3 is a graph showing the movement of the hands in the embodiments of FIGS. 1 and 2. FIG. The total moment of inertia around the fourth wheel 9 on the second hand 10 side from the hairspring 6C is approximately 0.02 mg.
mm5”/rad, attenuation coefficient C is approximately 800mgmm5
/rad, the spring constant of hairspring 6c is approximately 220m
gmm/rad. Here, the indicated position of the second hand lO, that is, the rotation angle of the fourth wheel θ
Then, θ=0 holds in the equation of motion Iθ+Cθ+,
The equation of motion can be solved by adding to this the condition that the main drive vehicle 6a rotates at approximately 3 rpm in steps of 0.25 seconds and that the speed and position do not change before and after the step drive. FIG. 3 shows the movement state of the second hand 10 when the hairspring 6C is wound up to a stable state after the battery is inserted. A smooth curve 30 from the lower left to the upper right indicates the indicated position of the second hand 10, and a sawtooth-like curve 31 indicates the angular velocity distribution with respect to the average angular velocity. Normally, the second hand 10 rotates 360 degrees per minute, so it rotates 6" in 1 second. From the curve 31, the second hand 10 moves approximately 1 in a straight line.
It rotates 6 @ in seconds, and from the angular velocity ratio curve 31, there is only an increase or decrease of about 3% with respect to the average angular velocity, so the second hand lO
appears to be an almost perfect sweep movement. 4, 5 and 6 show the moment of inertia I=0.
02mgmm5”/rad, spring constant = 220mg
mm/rad, and is a graph showing the movement state of the second hand when the product of the damping coefficient C and the number of drives per second S is equal to the spring constant; FIG. 4 shows S=4, FIG. 5 shows S=2, FIG. 6 shows the case where S=1. Indication curves 32.34 and 36 show the indicated position of the second hand lO, and 33.35 and 37 show the ratio of angular velocity to the average angular velocity. Figure 4 is the first
This is the case where the viscosity of the silicone oil 15 in the embodiment shown in FIGS.
The reduction ratio from to the conversion vehicle 6 is set to 1/2 or 1/4,
0 curve 3, which is the case when the viscosity of silicone oil is decreased
2.34 and 36 are quite wavy, with an angular velocity ratio of 3
3.35 and 37 vary from about 0.6 to 1.5, which is the minimum level required for a sweep hand movement watch. In order to reduce fluctuations in angular velocity, by storing the rotation angle for N steps (N>1) of the drive section in the joint mechanism, the torque fluctuation applied to the load mechanism can be reduced to 1/1 per step.
If it is set to N, the fluctuation will also be reduced to 1/N. Corresponding this with the constants mentioned above, we get the following. ■ is smaller than C, so ignore it. C/=t is the time required to create an angular shift at a constant speed when the joint mechanism is rotating at a constant speed with an angular shift in balance with the load torque of the load mechanism. Therefore, when multiplied by the number of steps S in which the drive section moves intermittently per second, it becomes the number of steps stored in the joint mechanism. That is, C×S/=
t×S=N. Here, since Ni1, in order to move smoothly, it is necessary that C×S>K. On the other hand, as shown in Figs. 4, 5, and 6, even if S changes, the magnitude of the angular velocity ratio can be kept constant by changing C and K accordingly, but the step interval is long, i.e. If S is small, the deviation of the instruction from the accurate sweep hand movement position will be large. If the period of deviation exceeds 1 second, the deviation from the second scale on the dial becomes irregular and noticeable, so S is preferably 1 or more.Furthermore, if a viscous fluid is used as the load mechanism, In particular, the load torque increases at low temperatures, and if the drive unit is a step motor, there is a risk of it not starting due to magnetic saturation or deviation from the stable position due to size constraints.
It is necessary to increase the speed reduction ratio to 1 or more and drive the motor reliably. Above, we have explained using a hairspring as a means to generate restoring torque, a viscous fluid as a means to generate load torque, and a step motor as an intermittent drive method. It goes without saying that the same effect can be obtained by using a combination of piezoelectric element or other communication methods in the intermittent drive method.Also, in the examples, specific dimensions and rotational speeds, etc. are described, but they are - This is an example and is flexible in design, so C×S
>K, there is no limitation on these values. [Effects of the Invention] As explained above, intermittent movement of the drive unit can be controlled using a joint mechanism in which the restoring torque increases as the phase difference increases, and a load mechanism in which the load torque increases as the angular velocity increases. ,
In sweep hand motion watches that smooth the movement of the second hand,
By setting S, the number of drives per second of the drive unit, and the moment of inertia, and K, the spring constant of C1, which is the damping coefficient, and setting SxC to be larger than K, a sweep hand movement clock in which the second hand moves smoothly was obtained. Furthermore, by setting S to 1 or more, it was possible to reduce indication deviation and ensure reliable driving compared to the case where the hands were moved accurately and continuously. There is plenty of room to choose the values of S, C, and the like even in ultra-small watches, etc., and as long as the value of SxC is greater than K, a sweep hand motion watch can be easily realized. Therefore, the significance of the present invention is enormous, and its effects are immeasurable.

[Brief explanation of the drawing]

1 and 2 are cross-sectional views showing one embodiment of the present invention. FIG. 3 is a graph showing the movement of the second hand in the embodiment shown in FIGS. 1 and 2. 4, 5 and 6 show the moment of inertia I=0.
02mgmm5”/rad, spring constant=220mgm
m/rad is a graph showing the movement state of the second hand when the product of the damping coefficient C and the number of drives per second S is equal to the spring constant. FIG. 7 is a plan view of another embodiment showing the action of the regulating lever. 2... Stator 3... Coil block 4... Rotor 6... Conversion wheel 7... Intermediate wheel 8... Oil rotor 9... Fourth wheel lO... Second hand and above Applicant Seiko Epson Corporation Representative Patent Attorney Kisanbe Meiki (and 1 other person) Figure 3 Figure 5

Claims (2)

[Claims] (1) Second hand, drive part that moves intermittently S times per second, restoring torque increases as the phase difference increases, and the spring constant of the restoring torque is Kmgmm/rad, joint mechanism, load as the angular velocity increases A sweep hand movement timepiece comprising a load mechanism in which torque increases and the attenuation coefficient of the load torque is Cmgmms/rad, characterized in that C×S>K. (2) A sweep hand movement clock characterized in that the number of times S of the driving part intermittently moves in one second is 1 or more.