JPH1155976A - Rotation speed control device and device provided with the same - Google Patents

Abstract

(57) [Problem] To provide a simple and inexpensive primary-battery unnecessary high-precision rotational speed control device and a device using the same. [MEANS FOR SOLVING PROBLEMS] A drive source for storing mechanical energy and the drive A train wheel for transmitting the mechanical energy stored in the source while gradually releasing it, and electrodes formed so as to store an electrorheological fluid (ER fluid) driven by the train wheel and apply a voltage to the ER fluid Simple and low cost by providing a speed control means, a generator driven by the speed increasing train and converting mechanical energy into electric energy, and means for applying a voltage generated by the generator to the ER fluid. Thus, it is possible to obtain an unnecessary high-precision rotation speed control device for the primary battery and a device using the same.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotational speed control device using a viscous fluid and an apparatus provided with the same.

[0002]

2. Description of the Related Art Several devices have been proposed which release accumulated mechanical energy while controlling the rotation speed and use it as a clock or the like. For example, JP-A-59-135388 and JP-B-3-3752 disclose devices. The mechanical energy stored in the mainspring is transmitted to the generator using a train, and the generator drives the crystal oscillator and the electronic circuit with the electric energy converted from the mechanical energy, and the electronic circuit controls the braking amount of the generator. There is described a technique of controlling the rotation speed by adjusting.

[0003]

An apparatus using such a rotation speed control device stores energy in a mainspring by a mechanical energy storage device, for example, an energy replenishing device using a manual or weight, and the energy is stored in the mainspring. A generator is driven by the supplied energy to generate power, and a crystal oscillator and a control IC are driven. The control IC can keep the rotation speed constant by controlling the rotation speed of the generator using the output of the crystal oscillator as a reference signal.

By using such a rotational speed control device, it is possible to obtain a highly accurate timepiece or the like that does not require a primary battery or a secondary battery.

However, such a rotation speed control device includes a crystal oscillator driving block, a block for creating a reference signal from the crystal oscillator output, a generator rotation speed detection block, a reference signal and rotation speed comparison block, and a generator rotation speed. Requires many blocks, such as control blocks. Also, the circuit of the generator rotation speed control block needs to directly control a large current generated from the generator.
Are complex and large. Therefore, there has been a problem that such a rotational speed control device and equipment using the same are complicated and costly.

[0006]

In order to solve the above-mentioned problems, the present invention uses the following means.

A first aspect of the present invention relates to a basic structure of the present invention, wherein a drive source for storing mechanical energy, a wheel train for transmitting the mechanical energy stored in the drive source while gradually releasing the drive source, and a drive train driven by the wheel train And a means for applying a voltage generated by the voltage generating means to the electrorheological fluid.

A second aspect of the present invention is characterized in that in the first aspect, the voltage generating means is a generator driven by the wheel train.

A third aspect of the present invention is characterized in that, in the first aspect, the voltage generating means is a photovoltaic element.

[0010] A fourth aspect of the present invention is characterized in that in the second aspect, there is provided means for changing a voltage applied to the electrorheological fluid according to a rotation speed.

A fifth aspect of the present invention is characterized in that in any one of the first to third aspects, there is provided means for changing a voltage applied to the electrorheological fluid in accordance with a torque generated by the driving source.

A sixth aspect of the present invention is characterized in that in any one of the first to third aspects, the driving source is a mainspring.

According to a seventh aspect of the present invention, the means for changing the voltage applied to the electrorheological fluid in accordance with the torque generated by the driving source detects the rotation difference between both ends of the mainspring. It is characterized by.

An eighth aspect of the present invention is characterized in that, in the seventh aspect, there is provided means for displaying a rotation difference between both ends of the mainspring.

A ninth aspect of the present invention is characterized in that in the second aspect, there is provided means for changing a voltage applied to the electrorheological fluid in accordance with a temperature.

According to a tenth aspect, in any one of the first to third aspects, a plurality of pairs of electrodes for applying a voltage to the electrorheological fluid are provided.

An eleventh aspect of the present invention is characterized by including the rotational speed control device according to any one of the first to third aspects.

By these means, according to the present invention, it is possible to obtain a simple and low-cost unnecessary high-precision rotation speed control device for a primary battery and a device using the same.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in more detail with reference to the drawings. FIG. 1 shows an outline of a timepiece device provided with a rotation speed control device according to an embodiment of the present invention. The timepiece device 30 of the present example includes a speed control device 3 in which the electrodes 5 are formed so that a voltage can be applied to the stored ER fluid 4, a power generation device 20 including a magnetized rotor 6, a stator 7, and a power generation coil 8. A rectifier circuit 9 for rectifying an alternating current obtained by rotation of the magnetized rotor 6, a power storage means 11 for storing the rectified current, and a voltage of the power storage means 11 adjusted and applied to the speed control device 3. The barrel 1 containing the mainspring 15, which is connected to the speed control device 3 and the power generation device 20 by the voltage adjusting means 13, the drive train 2, and supplies mechanical energy for driving them, and according to the generated force of the mainspring 15. It comprises a control means 40 for controlling the voltage adjusting means 13. ER
The fluid 4 may be any fluid whose viscosity resistance changes depending on an applied electric field, such as a liquid crystal or an ion exchange resin dispersed in an organic solvent. The control means 40 controls the control wheel train 16 so that the deflection of the mainspring 15 can be represented by the rotation difference between the inner end and the outer end thereof, and the control wheel train 16 controls the resistance value of the variable resistor 14 of the voltage adjusting means 13. It comprises a winding amount indicating needle 17 to be changed. In this example, the mainspring is used as an energy source for driving the timepiece device. However, a weight or the like is hung, and the energy at the time of falling or the energy at the time of compressing and injecting air into the container and blowing it out. Any device that can supply mechanical energy for driving the wheel train, such as using Although the capacitor 12 is used as the power storage unit 11, any device having a power storage capability such as a secondary battery may be used. Rectifier circuit 9
Is not limited to half-wave rectification using the diode 10 as in the present embodiment, but may be a full-wave rectification circuit or a rectification circuit using an inverter or the like.

In FIG. 1, the timepiece device of the present embodiment is shown using a conceptual diagram. The driving wheel train 2 and the governing device 3 are arranged so as to overlap the rectifier circuit 9 and the power storage means 11 in a plane. Therefore, the size of the entire apparatus is reduced.

A hand (not shown) is attached to the drive wheel train 2, and the time can be displayed by using the hands.

Here, the principle of the governor using the ER fluid will be described. In FIG. 1, the mechanical energy stored in the mainspring 15 of the barrel 1 in a steady state is the friction of the driving wheel train 2 and the bearing, the viscous resistance of the ER fluid 4 in the governing device 3, the magnetic loss of the generator 20, and the power generation. Although it is consumed by electric power and the like, for simplicity, the description will be given focusing on only the generated torque of the mainspring and the viscous resistance of the ER fluid.

As shown in FIG. 5, the driving torque from the mainspring 15 is almost constant irrespective of the rotational speed as indicated by a straight line 61 during a short time. When the rotation speed is changed without applying a voltage to the ER fluid 4, the load torque of the governor 3 is substantially proportional to the rotation speed, as indicated by 65. This is due to the inherent viscous resistance of the fluid. However, when a voltage corresponding to the number of revolutions is applied, the torque becomes as shown by a curve 62 or 66. The slope of the curve increases as the proportional constant of the applied voltage to the rotation speed increases.
This is because the effect of changing the viscous resistance by the applied voltage of the ER fluid 4 is added to the straight line 65.

Due to such characteristics, when the rotational speed is temporarily changed due to some disturbance, the governor 3 has the effect of the voltage change in addition to the normal viscous resistance increase, and quickly returns to a stable point. Rotation stability is higher than when no voltage is applied.

In general, the viscous resistance of a fluid changes with temperature as shown by a curve 90 in FIG. However, since the ER fluid has the effect of the voltage change on the rotation speed as described above, the fluctuation of the rotation speed due to the temperature is smaller than that of a normal fluid. Further, as will be described later, by setting the voltage applied to the ER fluid in proportion to the rotation speed to a value corrected for the temperature change, more stable rotation speed control can be performed.

The above description has been made on the assumption that the spring torque is constant. However, even when the mainspring torque fluctuates, the rotational speed can be kept constant by correcting the fluctuation with the voltage applied to the ER fluid. As shown by a curve 67 in FIG. 6, the generated torque of the mainspring 15 gradually decreases because it is released in accordance with the elapsed time from the start of driving the wheel train of the mainspring. That is, the mainspring torque changes from the straight line 61 to the straight line 63 in FIG. 5, and the rotation speed decreases from 64A to 64B. At this time, as described later, the ER fluid 4
By correcting the relationship between the rotational speed and the torque to 66, the rotational speed can be kept constant. It is needless to say that if the fluctuation of the viscous load torque of the ER fluid due to the temperature change or the fluctuation of the rotation speed due to the fluctuation of the mainspring driving torque does not cause a problem for the intended use, these corrections are not necessary. Also in this case, the characteristic of the load torque with respect to the rotation speed of the ER fluid is such that the effect of changing the viscous resistance by the applied voltage of the ER fluid 4 is added to the straight line 65 as shown by the curves 62 and 66 in FIG. The fluctuation of the rotation speed with respect to the fluctuation of the torque becomes smaller than the case where the voltage corresponding to the rotation speed is not applied.

In order to realize these corrections, as shown in FIG. 1, a speed controller 3 in which an ER fluid 4 is stored and an electrode 5 is formed so that a voltage can be applied to the ER fluid 4, and a power generator 2
0, a rectifying circuit 9 for rectifying the AC current generated by the power generation device 20, a power storage unit 11 for storing the rectified current,
A voltage adjusting means 13 for adjusting and applying the voltage of the power storage means 11 to the governing device 3; and a mainspring 15 which is coupled to the governing device 3 and the power generating device 20 by the driving wheel train 2 and supplies mechanical energy for driving these devices. And the control means 40 for controlling the voltage adjusting means 13 in accordance with the force generated by the mainspring 15 are required.

Hereinafter, the configurations of the speed control device 3, the voltage adjusting means 13, and the control means 40 will be described in detail.

As shown in FIG. 2, the governing device 3 of the present embodiment
An outer cylinder 51 that stores the ER fluid 4 and rotates together with a driving gear 52 that meshes with the drive train 2 (not shown), bearings 56 a and 56 b that support the outer cylinder 51, and an inner cylinder 53 that is fixed to the base plate 54 and does not rotate. ing. Further, the inner cylinder 53 is insulated from the ground plate by an insulating plate 55, and has a configuration in which the output voltage of the voltage adjusting means 13 is applied. Since the rotating outer cylinder 51 is always meshed with the driving wheel train 2, by electrically connecting the driving wheel train 2 or the barrel 1 to the main plate 54, the outer cylinder 51 is also connected to the main plate 54 without using a brush or the like. can do. FIG. 3 is a cross-sectional view of the governing device 3 along AA ′. Disc-shaped electrodes 57 and 58 are arranged between the outer cylinder 51 and the inner cylinder 53 so as not to contact each other. When the outer cylinder 51 rotates, the electrode 58 formed on the outer cylinder 51 also rotates, and viscous resistance is exerted by the ER fluid 4 filled between the outer cylinder 51 and the electrode 57 formed on the non-rotating inner cylinder 53. Reference numeral 501 denotes an insulating packing which rotates together with the outer cylinder 51 and seals the ER fluid 4 so as not to flow outside.

The viscous resistance changes depending on the voltage between the electrodes 57 and 58, but is not a straight line as shown by a curve 60 in FIG. The region 602 where the change in the viscous resistance to the applied electric field E is large is more desirable than the regions 601 and 603. As shown in FIG. 3, by forming the electrodes 57 and 58 in a disk shape and laminating the electrodes which are alternately mounted on the outer cylinder 51 and the inner cylinder 53, the distance between the electrodes can be freely set. Therefore, the electric field E
Can be set in the region 602 where the viscous resistance of the ER fluid can be effectively controlled.

Next, referring to FIG. 7, the voltage adjusting means 1 of this embodiment will be described.
3 and the control means 40 will be described. The control means 40
Inner wheel 70, inner wheel 7 directly connected to the inner end of the mainspring 15
0, an inner end transmission system 80 composed of a train of wheels 71 and 73 connecting the hoisting amount indicating wheel 75, an outer end wheel 72 directly connected to the outer end of the mainspring 15, an outer end wheel 72 and a hoisting amount indicating wheel 75.
And the outer end transmission system 81 of the train wheel 74 that connects the two. The two transmission systems have the same reduction ratio from the mainspring 15 and are set to drive the hoisting instruction wheel 75 in the opposite direction.
For this reason, the winding amount indicating needle 17 does not move outside the predetermined range, and indicates a winding amount of the mainspring, that is, a position corresponding to the generated torque of the mainspring.

Further, a capacitor 12 that rectifies the output of the power generator 20 and stores the power is connected to both ends of the variable resistor 14. Therefore, a voltage proportional to the rotation speed is applied to both ends of the variable resistor 14 without providing any means such as a detecting element.

Now, consider a case where the outer wheel 72 of the mainspring 15 is wound up by a crown or the like (not shown). At this time, the outer end transmission system 81 rotates in the direction of arrow 83, and
Rotate clockwise. At this time, the winding amount indicating vehicle 7
5, the winding amount indicating needle 17 having an electrode 78 at the tip for extracting a voltage from the variable resistor 14 also moves to the left, and the voltage output to the electrode 78 increases. As a result, the voltage applied to the governing device 3 also increases. At this time, in FIG.
The torque due to the viscous resistance of the fluid 4 becomes a curve 62, and the rotation speed becomes 64A.

On the other hand, the mainspring 15 is gradually released while driving the generator. At this time, the inner end transmission system 80 is indicated by arrow 8
2 to rotate the hoisting instruction wheel 75 counterclockwise. At this time, the winding amount indicating needle 17 moves to the right side, and a gradually lower voltage is applied to the electrode 78. As a result, a gradually lower voltage is also applied to the governor 3. The mainspring is released and the torque is increased by the straight line 6 in FIG.
When the voltage drops to 3, the applied voltage to the ER fluid 4 also drops, so that the torque due to the viscous resistance becomes a curve 66, and the rotation speed is also kept at 64A. In this way, constant rotation speed control can be realized with a simple circuit configuration without using a force sensor or the like.

Furthermore, by making the winding indicator hand visible from the character side, it is possible to know how long the watch will last, thereby improving the convenience of the user.

As shown in FIG. 7, the winding amount indicating needle 17 and the electrode 78 are connected by a bimetal 77.
As described above, generally, the viscous drag of a fluid is represented by the curve 9 in FIG.
It changes with temperature change as shown in FIG. However, when the bimetal 77 is deformed due to a temperature change, the position of the electrode 78 changes accordingly, so that the voltage applied to the ER fluid is corrected according to the temperature, and the rotation speed is properly adjusted as in the case of the torque fluctuation of the mainspring. Can be kept.

As described above, the voltage adjusting means 13,
The control means 40 and the bi-metal 77
If the fluctuation of the viscous load torque of the R fluid or the fluctuation of the rotation speed due to the fluctuation of the mainspring driving torque does not cause a problem for the intended use, it can be omitted.

As described above, the timepiece device 30 provided with the rotation speed control device of the present embodiment shown in FIG.
To the drive train 2
By applying the electric power generated by the power generating device 20 combined with the governing device 3 and the mainspring 15 which is a supply source of mechanical energy with a voltage corrected according to the torque of the mainspring 15, a complicated electronic circuit is used. It is possible to perform low-cost and high-accuracy rotation speed control without any problem. Also, as shown in FIG. 3, the electrodes 57 and 58 for applying a voltage to the ER fluid 4 in the governing device 3 are formed in a disk shape, and the outer cylinder 51 and the inner cylinder 5 are formed.
3, it is possible to increase the change in the viscous drag torque of the ER fluid 4 even at a low voltage, and it is possible to directly control the ER fluid 4 at a low voltage achievable in a watch. it can. Further, by connecting the winding amount indicating needle 17 and the electrode 78 with the bimetal 77, a change in viscous resistance to a temperature change of the ER fluid 4 can be corrected, and more accurate rotation speed control becomes possible.

In the above embodiment, a cylindrical vessel is used for the speed governing device 3 for storing the ER fluid 4, and the inner cylinder 53 is fixed and the outer cylinder 51 is rotated. Needless to say, the cylinder 53 may be rotated.

Further, the shape of the governing device 3 is not limited to a cylinder, but may be a disk-shaped governing device 100 as shown in FIG.
4, a lower disk 101, a concentric electrode 103 mounted on the lower disk 101, an upper disk 102 driven by the driving wheel train 2, and an electrode 103 mounted on the upper disk 102. And the electrode 104 is formed at an intermediate pitch of the electrode 103 so as not to contact the ER.
A configuration in which the fluid 4 is stored may be used.

Reference numerals 502 and 503 denote insulating packings which seal the ER fluid 4 so as not to flow out. The ER in the speed governor is the same as the cylindrical governor 3.
By having a structure in which electrodes for applying an electric field to the fluid are stacked,
The viscous resistance of the ER fluid can be effectively controlled with a low voltage from the voltage adjusting means 13. Such a governing device 10
0 is advantageous for making the governing device thinner than the cylindrical governing device 3 described above.

In the above-described embodiment, a method for realizing the control for keeping the rotation speed constant has been described. However, by controlling the voltage applied to the ER fluid, an arbitrary rotation speed can be realized. FIG. 10 shows a warning device using such a rotation speed control device.

The warning device 120 according to the present embodiment includes a speed control device 3 containing an ER fluid 4, a magnetized rotor 126, and a stator 12.
7, a power generating device 140 having a power generating coil 128, a light emitting element 129 that emits light by electric power obtained by rotation of the magnetized rotor 126, and a power generating device 140
And a barrel 121 that stores a mainspring 135 that is coupled to a reflector 131 that reflects the light of the light emitting element 129 and that supplies mechanical energy to drive these. In this example, the mainspring is used as an energy source for driving the timepiece device. However, a weight or the like is hung, and the energy at the time of falling or the energy at the time of compressing and injecting air into the container and blowing it out. Any device that can supply mechanical energy for driving the wheel train, such as using

In the warning device 120 configured as described above, in the daytime when the surroundings are bright, the generated voltage of the solar cell 130 is applied to the ER fluid 4, but the viscous resistance does not largely rotate.
At night, when the voltage generated by the solar cell 130 decreases, the viscous resistance of the ER fluid decreases, and rotation starts. At this time, since the power generation device 140 also rotates, the light emitting element 129 is turned on by the generated power. Further, since the reflection plate 131 is also driven by the rotation of the train wheel 122, the light is reflected / blinks and functions as a warning device.

As described above, the warning device 120 having the rotation speed control device of this embodiment uses the ER fluid 4 for the speed control device 3 and uses the voltage generated by the solar cell 130 as the voltage applied to the ER fluid 4. The power generated by the power generating device 140 coupled to the speed control device 3 and the mainspring 135 serving as a source of mechanical energy by the drive train 122 is used for light emission of the light emitting element 129, thereby eliminating the need for a power source. A warning device that automatically flashes can be obtained. In addition, this warning device does not require a secondary power supply, unlike a device that accumulates power from a solar cell and emits light at night, so there is no failure due to deterioration of the secondary power supply.
It can be used semi-permanently.

The present invention is not limited to the timepiece device and the warning device described in the above embodiment. Timer that requires control of rotation speed, recorder for temperature / humidity, etc.
The present invention can be applied to a star tracking device, a record player, a music box, a playground equipment such as a mainspring-driven model or doll, and the like.

These devices to which the rotation speed control device of the present invention is applied can be configured without using an IC because a complicated control circuit is not required for rotation speed control. For this reason, it has never been said that the IC breaks down due to static electricity or the like during use and rotation speed control becomes impossible. Further, when a failure occurs, there is no problem that the IC cannot be obtained because the IC cannot be obtained, so that the repair is easy. In addition, the rotation speed control device of the present invention has a simple configuration, so that the cost is low, and the user can obtain equipment with high-precision rotation speed control at low cost.

[0048]

As described above, according to the present invention, the following effects can be obtained.

1. A drive source that stores mechanical energy, a train wheel that transmits mechanical energy stored in the drive source while gradually releasing the same, and an electrorheological fluid driven by the train wheel are stored. Governing means;
By providing a means for applying the voltage generated by the voltage generating means to the electrorheological fluid, simple and low cost
A highly accurate rotation speed control device that does not require a secondary battery can be obtained.

2. Since the voltage generating means is a generator driven by the wheel train or a photovoltaic element, no separate power supply is required for detecting the rotation speed and illuminance,
Low cost.

3. By providing a means for changing the voltage applied to the ER fluid according to the rotation speed, the fluctuation of the rotation speed with respect to the fluctuation of the driving torque can be made smaller than when no voltage is applied.

4. By providing a means for changing the voltage applied to the ER fluid in accordance with the torque generated by the drive source, it is possible to correct the rotational speed variation due to the variation in the torque of the drive source.

5. Since the means for changing the voltage applied to the ER fluid in accordance with the torque generated by the drive source is performed by detecting the rotation difference between both ends of the mainspring, a simple circuit configuration is used without using a force sensor or the like. Constant rotation speed control can be realized.

6. By providing a means for displaying the rotation difference between both ends of the mainspring, it is possible to know how long the device is to be maintained, thereby improving the user's convenience.

7. Because the driving source is the mainspring,
5.6. Can be realized.

8. Since there is means for changing the voltage applied to the ER fluid in accordance with the temperature, the change in the viscous resistance with respect to the temperature change can be corrected, and the rotation speed can be controlled with higher accuracy.

9. By using a configuration in which a plurality of pairs of electrodes for applying an electric field to the ER fluid in the speed governor are stacked, the viscous resistance of the ER fluid can be effectively controlled at a low voltage.

10. A device to which the rotational speed control device of the present invention having these effects is applied can be configured without using an IC because a complicated control circuit is not required for controlling the rotational speed. As a result, the IC breaks down due to static electricity during use,
The rotation speed control is not disabled. Should a failure occur, it is easy to repair without any failure that the IC cannot be obtained because it is not available. Further, the rotation speed control device of the present invention has a simple configuration, so that the cost is low,
The user can inexpensively obtain equipment with high-precision rotation speed control.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of a timepiece device provided with a rotation speed control device according to an embodiment of the present invention.

FIG. 2 is a diagram showing a configuration of a rotation speed control device shown in FIG.

FIG. 3 is an enlarged sectional view showing a configuration of a rotation speed control device shown in FIG. 2;

FIG. 4 is a diagram showing a change in viscous resistance to an applied electric field of an ER fluid.

FIG. 5 is a diagram illustrating the principle of the rotation speed control of the rotation speed control device shown in FIG. 1 based on the relationship between the generated torque of the mainspring and the torque due to the viscous resistance of the ER fluid.

FIG. 6 is a diagram showing a change in torque of the mainspring shown in FIG. 1 depending on an elapsed time.

FIG. 7 is a diagram illustrating a configuration of a control unit that controls the voltage adjustment unit illustrated in FIG. 1;

FIG. 8 is a diagram showing a change in a viscous resistance with respect to a temperature of a fluid.

FIG. 9 is a diagram showing another configuration of the rotation speed control device.

FIG. 10 is a diagram illustrating a configuration of a warning device including a rotation speed control device according to another embodiment of the present invention.

[Explanation of symbols]

1. Cage box 2. Drive train 3. Speed regulator 4. ER fluid 5. Electrode 6. Magnetized rotor 7. Stator 8. Generating coil 9. Rectifier circuit 10. Diode 11. Electricity storage means 12. Capacitor 13. Voltage adjusting means 14. Variable resistor 15. Spring 16. Control wheel train 17. Winding amount indicating hand 18. Time indicating hand 20. Power generating device 30. Clock device 40 Control means 51 Outer cylinder 52 Drive gear 53 Inner cylinder 54 Ground plate 56 Bearings 57, 58 Electrodes 60 Viscous resistance of ER fluid and applied electric field Relationship 61, 63 ... Relationship between mainspring generated torque and rotation speed 62, 65, 66 ... Relationship between viscous resistance torque of ER fluid and rotation speed 67 ... Relationship between mainspring generated torque and elapsed time 70 ... Inner end wheel 72 ... outer edge 76 ... hoist weight indicator needle 77 .. bimetallic 78 · electrode 100 · discoid governor 120 ... ER Fluid Warning device using

Claims (11)

[Claims] 1. A drive source for storing mechanical energy, a wheel train for transmitting mechanical energy stored in the drive source while gradually releasing the drive source, and a speed control means containing an electrorheological fluid driven by the wheel train. And a means for applying a voltage generated by the voltage generating means to the electrorheological fluid. 2. A rotation speed control device according to claim 1, wherein said voltage generating means is a generator driven by said wheel train. 3. The rotation speed control device according to claim 1, wherein said voltage generating means is a photovoltaic element. 4. A rotation speed control device according to claim 2, further comprising means for changing a voltage applied to said electrorheological fluid in accordance with a rotation speed. 5. A rotation speed control device according to claim 1, further comprising means for changing a voltage applied to said electrorheological fluid in accordance with a torque generated by said drive source. 6. A rotation speed control device according to claim 1, wherein said drive source is a mainspring. 7. The device according to claim 6, wherein the means for changing the voltage applied to the electrorheological fluid in accordance with the torque generated by the drive source is performed by detecting a rotation difference between both ends of the mainspring. Rotation speed control device. 8. A rotation speed control device according to claim 7, further comprising means for displaying a rotation difference between both ends of said mainspring. 9. A rotation speed control device according to claim 2, further comprising means for changing a voltage applied to said electrorheological fluid in accordance with a temperature. 10. A rotation speed control device according to claim 1, wherein a plurality of pairs of electrodes apply a voltage to said electrorheological fluid. 11. An apparatus having the rotation speed control device according to claim 1.