JP2008233795A - Polymer transducer, and key device and wind instrument using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polymer transducer which can be used with a comparatively large stroke, and can adjust pressing force in various ways, and a key device and a wind instrument using the same. <P>SOLUTION: The polymer transducer comprises: a coil spring 2 which is fabricated into a coil shape, in a state in which a band shaped expansion/contraction element 4 in which electrodes are arranged on both faces of an expandable/contractible polymer membrane, is laminated on one face of an intensity member 5; and a control means 3 for applying voltage between electrodes of the expansion/contraction element 4. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a polymer transducer, a key device using the polymer transducer, and a wind instrument.

As a transducer such as an actuator used in a small device, a polymer transducer using an electroactive polymer is known. This polymer transducer uses a stretch element in which electrodes made of a conductive stretch material are arranged on both sides of an insulating polymer film such as silicon rubber or acrylic resin. When a voltage is applied to the electrodes, the electrostatic attraction between these electrodes attracts them in the opposing direction of the electrodes, and as a result, the polymer film has a property of contracting in the thickness direction and expanding in the plane direction.
As a transducer capable of taking out force from the expansion / contraction element, Patent Document 1 proposes a unimorph structure transducer in which a metal thin film is attached to one surface along the opposing direction between both electrodes in the expansion / contraction element. By applying a voltage to the metal film, the metal thin film can be bent so as to bend.

On the other hand, as shown in Patent Document 2, a trumpet or a tuba that can be played by pressing a plurality of valve keys according to the pitch or pitch while performing a wind performance through a mouthpiece. For wind instruments such as horns, it is desirable for beginners, handicapped persons, weak children or elderly people to have heavy keys so that they can be operated easily. It is being considered to avoid burdens.
JP 2006-204099 A Japanese Patent Laid-Open No. 2000-155569

  However, when the polymer transducer described in Patent Document 1 is used as an actuator, only a bending operation in the direction of bending the metal thin film can be performed. Therefore, even if this is applied to a key device such as a wind instrument, a pressing operation is performed. It is difficult to secure a stroke for the operation, and there is a limit to the adjustment of the operation feeling.

  The present invention has been made in view of the above circumstances, and provides a polymer transducer that can be used with a relatively large stroke and that can be easily applied to wind instruments that can adjust various pressing operation forces. An object is to provide a key device and a wind instrument using the same.

The polymer transducer according to the present invention includes a coil spring formed by forming a strip-shaped stretch element having electrodes disposed on both sides of a stretchable polymer film into a coil shape in a state of being laminated on at least one surface of a strength member, And a control means for applying a voltage between the electrodes of the elastic element.
With such a configuration, when the expansion / contraction element expands and contracts in the surface direction due to the electrostatic attractive force between the electrodes, the coil spring can expand and contract the coil length while changing the coil diameter. At this time, because of the shape of the coil spring, expansion and contraction of the expansion and contraction element occurs in the spiral direction of the coil, and the length of the spiral is sufficiently larger than the entire length of the coil, so that the expansion and contraction length is increased. As a result, a large stroke can be secured as the coil spring. Then, by setting the length, the number of turns, the spring constant, the applied voltage, and the like of the coil to appropriate values, the coil can be adjusted to have a desired spring characteristic.
As the strength member, a material having a higher elastic modulus than that of the expansion / contraction element is selected to such an extent that the coil shape of the coil spring can be maintained.

In this polymer transducer, the expansion element is preferably arranged on one surface of the strength member, particularly on the outer peripheral surface of the coil spring.
When the expansion / contraction element is arranged on the outer peripheral surface of the coil spring, the coil length is increased while the coil diameter of the coil spring is reduced by applying a voltage to extend the expansion / contraction element.
In the polymer transducer, a groove may be formed in the strength member along the length direction, and the expansion / contraction element may be held in the groove.
When the expansion / contraction element is housed in the groove as described above, the expansion in the width direction of the expansion / contraction element is restricted by the inner surface of the groove, and can be effectively expanded in the length direction.
In addition, as the expansion / contraction element, a plurality of the polymer films may be laminated via electrodes, and the spring constant can be increased by the amount of lamination.

A key device using such a polymer transducer includes a key portion to be pressed and the polymer transducer, and a coil spring of the polymer transducer is continuously provided along the pressing direction of the key portion. It is characterized by.
Further, the wind instrument includes a cylinder connected to a tube constituting the wind instrument, a piston that opens and closes the tube by reciprocating in the cylinder, and the key device, and a key portion of the key device. Is connected to the piston.
That is, since the polymer transducer is in the shape of a coil spring, a large stroke can be secured, and an arbitrary operational feeling can be obtained by adjusting the spring characteristics.

According to the polymer transducer of the present invention, a large stroke can be secured by adopting the shape of the coil spring, and the length, number of turns, spring constant, applied voltage, etc. of the coil are set to appropriate values. Thus, it can be adjusted to a desired spring characteristic.
According to the key device and wind instrument using this polymer transducer, the stroke when the key portion is pressed is large, and an arbitrary operation feeling can be obtained by adjusting the spring characteristics. Not only can beginners and disabled persons, weak children or elderly people easily operate keys.

Hereinafter, embodiments of a polymer transducer, a key device, and a wind instrument of the present invention will be described with reference to the drawings.
As shown in FIG. 1, the polymer transducer 1 of this embodiment includes a coil spring 2 and a control means 3 for expanding and contracting the coil spring 2, and the coil spring 2 includes a strip-shaped expansion element 4, and It is set as the structure shape | molded in the coil shape in the state which has arrange | positioned the expansion-contraction element 4 on the outer peripheral surface with the strength member 5 laminated | stacked on the single side | surface of this expansion-contraction element 4. FIG.

The stretchable element 4 is configured such that a plurality of layers of stretchable polymer films 6 and layered electrodes 7 are alternately stacked, and the layer of the electrode 7 is disposed on the outermost layer. FIG. 2 shows the state of the strip A in which the coil spring 2 is linearly expanded. In FIG. 2, the polymer film 6 of the expansion / contraction element 4 has only one layer, and the electrode 7 has only one pair on both sides. Show.
The polymer film 6 is a polymer material having dielectric properties and elastically deformable, for example, a polymer material such as a silicone resin or an acrylic polymer formed into a thickness of, for example, about 5 μm to 50 μm by a spin coater. It is composed of
In addition, the electrode 7 is configured, for example, by spraying a solvent containing carbon particles on both surfaces of the polymer film 6 to a thickness of, for example, 5 μm to 15 μm. have.

On the other hand, the strength member 5 is made of a material that is relatively soft and easily deformable, such as polyethylene resin, but is made of a material having a higher elastic modulus than the expansion element 4 and maintains the coil shape of the coil spring 2. . In the example shown in FIGS. 1 to 3, the strength member 5 has a square cross section having the same width as the width of the strip A of the coil spring 2.
The coil spring 2 is formed by rolling the strip A while twisting the strip A so that the width direction of the strip A is the length direction of the coil, and forming it into a coil shape.
The control means 3 is connected to each electrode 7 of the expansion / contraction element 4 and applies a voltage between a pair of electrodes 7 facing each other with a polymer film 6 interposed therebetween. It is composed of

  In the polymer transducer 1 configured as described above, when a voltage is applied between the pair of electrodes 7 via the polymer films 6 of the expansion and contraction elements 4 by the control means 3, electrostatic attraction is generated between the electrodes 7. Acts to stretch the polymer film 6 in the plane direction while contracting in the thickness direction. In this case, since the expansion / contraction element 4 is in the shape of a strip and is formed in a coil shape, the extension is mainly performed in the length direction of the strip, in other words, in the spiral direction of the coil, and the overall length of the coil spring 2 is increased. Will stretch. At this time, since the strength member 5 lined on the inner peripheral surface of the coil spring 2 does not stretch due to voltage application, the expansion / contraction element 4 increases the coil length while reducing the diameter of the coil spring 2 as a whole. Become.

  In this polymer transducer 1, the length of the strip in the spiral direction is larger than the length of the coil due to the expansion / contraction element 4 being the coil spring 2, and the expansion / contraction length generated in the long strip is large. Therefore, the expansion and contraction of the coil length, that is, the stroke can be increased. The spring characteristics of the coil spring 2 can be adjusted by controlling the applied voltage, as well as by adjusting the materials and dimensions of the expansion / contraction element 4 and the strength member 5, and these can be adjusted appropriately. By setting the value, a desired spring characteristic can be obtained.

The spring characteristics of such a polymer transducer 1 are determined as follows.
In the polymer transducer 1, in the state of the strip A shown in FIG. 2 before being formed as the coil spring 2, the electrostatic attractive force F applied when the voltage V is applied between the electrodes 7 is the width of the strip A Where b is the length, L is the thickness, d is the thickness of the polymer film 6, and h is the thickness of the strength member 5, the following equation (1) is obtained.

Here, C is a capacitance, ε0 is a dielectric constant in vacuum (= 8.85 × 10 ⁻¹² F / m), and εr is a relative dielectric constant of the polymer film 6 (for example, εr = 3). In addition, S shows the area (Lxb) of the strip A.
When the stress applied to the strength member 5 when a voltage is applied is σ, the stress σ is obtained by the following equation (2) obtained by dividing the electrostatic attractive force F by the area of the strip A.

Next, this strip A is formed into a coil spring 2 with the coil length CL, the average coil diameter R, and the number of coil turns N, with the expansion / contraction element 6 disposed on the outer peripheral side as shown in FIG.
When the moment generated in the coil by the electrostatic attractive force F applied to the polymer film 6 in the state of the coil spring 2 is M, the angle (called the twist angle) φ (°) at which the coil is twisted is the longitudinal elastic modulus (Young When the ratio is E, it is expressed by the following equation (3).

  Here, the relationship between the moment M and the stress σ is expressed by equation (4).

  Therefore, when the equations (2) and (4) are substituted into the equation (3), the twist angle φ (°) becomes the equation (5).

  On the other hand, the relationship between the average coil diameter R of the coil spring 2, the number of turns N, and the length L of the strip is expressed by the following equation (6).

  The spring constant K (N / m) is expressed by the following equation (7).

Here, γ is a coefficient, and is a value determined by the width b of the strip A and the thickness h of the strength member 5.
The coil length CL is expressed by the following equation (8), assuming that there is a gap that is 0.5 times the coil thickness (width b of the strip A).

  That is, when the voltage V is applied to the coil spring 2 of the polymer transducer 1, a displacement of the twist angle φ shown in the equation (5) occurs, and the winding number N changes accordingly. Since the total length L of the strip A does not change, the average coil diameter shown by the equation (6), the coil length of the equation (8), and the spring constant of the equation (7) change.

Next, an embodiment in which the thus configured polymer transducer 1 is applied to a wind instrument key device will be described.
The wind instrument 11 is a trumpet shown in FIG. 3 and has a key device 13 for operating three piston-type valves 12.
As shown in FIGS. 4 and 5, the key device 13 is connected to a cylindrical cylinder 14 extending in the vertical direction, a piston 15 disposed in the cylinder 14 and capable of reciprocating, and an upper portion of the piston 15. And the polymer transducer 1 is pressed by a player and the coil spring 2 of the polymer transducer 1 biases the piston 15 upward on the inner bottom of the cylinder 14. It is the structure provided.

The first tube 17 and the second tube 18 are connected to the cylinder 14 so as to be spaced apart vertically on one side, and the second tube 18 is connected to the other side that is 180 ° apart. The third tubular body 19 is connected so as to extend. Further, the upper piston 20 for connecting the first tube body 17 and the third tube body 19 to the internal piston 15, and the second tube body 18 and the third tube body 19 are connected to each other. The lower hole 21 is formed so as to be spaced apart from each other in the vertical direction, and depending on the position of the piston 15, one of the holes 20, 21 is configured to connect the pipe bodies 17 to 19, and the position of the piston 15 is changed. Thus, the pitch can be adjusted by changing the length of the pipe. The valve 12 is constituted by these tube bodies 17 to 19, a cylinder 14, and a piston 15.
In the figure, reference numeral 22 denotes a stopper that regulates the raised position of the piston 14.

FIG. 4 shows a state in which no voltage is applied to the coil spring 2 of the polymer transducer 1, and when the key portion 16 is pressed in this state, an operation reaction force based on the elasticity of the material of the coil spring 2 acts. To do.
When a voltage is applied to the coil spring 2 of the polymer transducer 1 as shown in FIG. 5, the coil spring 2 tends to expand. However, since the arrangement length in the cylinder 14 is restricted, the coil spring 2 has a length. It acts in the direction of increasing its urging force without changing. Therefore, when the key portion 16 is pressed in this state, the operation reaction force is strengthened compared to the state shown in FIG.

Thus, by using the polymer transducer 1 for the key device 13 of the valve 12, the coil spring 2 can secure a large stroke, and the applied voltage is set to reduce the reaction force during the pressing operation. It can be adjusted to an appropriate size.
That is, as shown in FIG. 6 with various spring characteristics indicated by (A), (B), and (C), the initial pressing force when the key portion 16 is pressed (the stroke indicated by B in the figure is 0). (The biasing force of the coil spring at the initial position) can be arbitrarily set, and the change in the pressing force (inclination in the figure) within the stroke range until the key portion 16 is fully pressed can be arbitrarily set. An operational feeling can be obtained.

FIG. 7 shows another embodiment of the polymer transducer of the present invention. The polymer transducer 31 has a configuration in which the strength member 33 in the coil spring 32 is formed larger than the width of the expansion / contraction element 4 and the expansion / contraction element 4 is held in a groove 34 formed in the outer peripheral portion of the strength member 33. ing. Other configurations are the same as those of the above-described embodiment, and the same reference numerals are given and description thereof is omitted.
The stretchable element 4 expands in the plane direction when a voltage is applied to the electrode 7 and extends mainly in the length direction of the strip as described above, but slightly expands in the width direction as well.
Therefore, in the polymer transducer 31 configured as in the embodiment of FIG. 6, since the expansion / contraction element 4 in the coil spring 32 is held in the groove 34 of the strength member 33, the expansion / contraction element 4 extends in the width direction. It is constrained by the inner surface of the groove 34 and can be effectively extended in the length direction.

A specific example of the spring characteristics of the coil spring in the polymer transducer having the above configuration will be described.
The shape of one embodiment shown in FIG. 1 is adopted as the coil spring. Then, 20 layers of polymer films were laminated via electrodes as the stretchable element, and a strength member made of polyethylene resin was lined. The Young's modulus E of the stretchable element is E = 7.6 × 10 ⁸ N / m ² , the width b of the strip is b = 2 mm, the length L is L = 942 mm, and the thickness d of each layer of the polymer film is d = 10 μm and the thickness h of the strength member was h = 1 mm. The thickness of the electrode is 10 μm.
This material was formed into a coil spring having an average coil diameter R of R = 10 mm and a winding number N of N = 30. The coefficient γ in the equation (7) is γ = about 7 in the case of a rectangular cross section with b / h = 2.
Table 1 shows changes in the twist angle φ, the number of turns N, the average coil diameter R, the coil length CL, and the spring constant K when the applied voltage is increased.

As is apparent from Table 1, it can be seen that the coil length and the spring constant of this polymer transducer are changed by changing the applied voltage.
On the other hand, Table 2 shows changes in the force P when the applied voltage is raised in a state where both ends of the coil spring are constrained at 90 mm intervals so that the coil length does not change. In Table 2, the coil length CL indicates the length when the positions of both ends of the coil spring are not constrained.

As shown in Table 2, a force P is generated in the coil spring.
In light of the results shown in Table 1, it can be seen that this polymer transducer has a large stroke and a small force. In other words, a large stroke can be generated with a small force.

As mentioned above, although embodiment of this invention was explained in full detail with reference to drawings, the concrete structure is not restricted to this embodiment, The design change etc. of the range which does not deviate from the summary of this invention are included.
For example, in the embodiment, the expansion / contraction element is disposed on the outer peripheral side of the coil spring and the strength member is disposed on the inner peripheral side. Conversely, the strength member is disposed on the outer peripheral side of the coil spring, and the expansion / contraction element is disposed on the inner peripheral side. It may be arranged. In that case, it is contracted in a state where a voltage is applied, and when the application of the voltage is canceled, it expands while reducing the coil diameter.
Moreover, although only the thing which laminated | stacked the strength member on the single side | surface of the expansion / contraction element (unimorph type) was shown, any structure of what laminated | stacked the expansion / contraction element on both surfaces (bimorph type) shall be included.

It is a longitudinal section showing one embodiment of a polymer transducer of the present invention. The coil spring of FIG. 1 is developed into a band plate, (a) is a front view, and (b) is a plan view. It is a perspective view which shows the trumpet as embodiment of the wind instrument to which the polymer transducer of FIG. 1 is applied. FIG. 4 shows an embodiment of a key device in the trumpet of FIG. 3, in which no voltage is applied to the polymer transducer, (a) is a free state, and (b) is a longitudinal sectional view showing a state of being pressed. is there. In the key device shown in FIG. 4, when a voltage is applied to the polymer transducer, (a) is a free state, and (b) is a longitudinal sectional view showing a state where a pressing operation is performed. It is the graph which showed the thing of various spring characteristics regarding the polymer transducer of this invention. It is a longitudinal cross-sectional view which shows other embodiment of the polymer transducer of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Polymer transducer, 2 ... Coil spring, 3 ... Control means, 4 ... Telescopic element, 5 ... Strength member, 6 ... Polymer film, 7 ... Electrode, 8 ... Variable power supply, 9 ... Switch, 11 ... Musical instrument, 12 ... Valve, 13 ... Key device, 14 ... Cylinder, 15 ... Piston, 16 ... Key part, 17, 18, 19 ... Tube, 20,21 ... Hole, 22 ... Stopper, 31 ... Polymer transducer, 32 ... Coil spring, 33 ... Strength member, 34 ... Groove

Claims (7)

  A voltage is applied between the coil spring formed by coiling a strip-shaped stretch element in which electrodes are arranged on both sides of a stretchable polymer film and laminated on at least one side of the strength member, and the electrode of the stretch element. A polymer transducer comprising control means for applying.   The polymer transducer according to claim 1, wherein the elastic element is provided on one surface of the strength member.   The polymer transducer according to claim 2, wherein the expansion element is disposed on an outer peripheral surface of a coil spring.   The polymer according to any one of claims 1 to 3, wherein a groove is formed in the strength member along a length direction, and the elastic element is held in the groove. Transducer.   5. The polymer transducer according to claim 1, wherein the stretchable element is formed by stacking a plurality of the polymer films via electrodes.   A key portion to be pressed and the polymer transducer according to any one of claims 1 to 5 are provided, and a coil spring of the polymer transducer is continuously provided along a pressing direction of the key portion. Key device characterized by.   A cylinder connected to a tubular body constituting a wind instrument, a piston that opens and closes the tubular body by reciprocating in the cylinder, and a key device according to claim 6, wherein the key portion of the key device includes: A wind instrument connected to the piston.

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