JPH0373360A - Piezoelectric hammer - Google Patents

Abstract

PURPOSE:To increase wire stroke relatively to the quantities of piezoelectric elements displaced by deforming an elastic member, to which a printing wire is fixed, by the two piezoelectric elements positioned at a specific distance. CONSTITUTION:One end section of a piezoelectric element 25 is fixed to a fixing member 22, and the other end is installed so as to be pressure-welded near the central section of a hammer base 23. One end section of a piezoelectric element 26 is fastened to the fixing member 22, and the other end is mounted so as to be pressure-welded to a section between the pressure-welding section of the piezoelectric element 25 and a fixing end in the hammer base 23. Since a printing head 10 is constituted by using a piezoelectric hammer, to which the two piezoelectric elements 25, 26 are set up so that the directions of the extension of the elements 25, 26 are repulsed mutually regarding one hammer base 23 to which a printing wire 24 is fastened, the quantity of the hammer base 23 deformed can be increased, and the stroke of the printing wire 24 can be made larger than conventional constitution. When a distance between the two piezoelectric elements is brought to approximately 3mm-5mm, the enlargement ratio of displacement is elevated.

Description

[Detailed Description of the Invention] Table of Contents Overview Industrial Application Fields Prior Art Problems to be Solved by the Invention Means for Solving the Problems Implementation Examples Regarding the hammer, the purpose is to provide a piezoelectric hammer that is small and has a large wire stroke, and one longitudinal end of the hammer is fixed to a fixed member, and the other end of the elastic member is provided with a wire that is approximately perpendicular to the longitudinal direction of the elastic member. A printing wire is attached so that the first piezoelectric element has one end pressed against the elastic member and the other end fixed to the fixing member, and when the first piezoelectric element is expanded, the elastic member The elastic member is provided so as to be pressed in a direction substantially opposite to the protruding direction of the printing wire, one end of which is pressed into contact with a portion of the elastic member between the printing wire mounting portion and the pressure contact portion of the first piezoelectric element, and the other end of which is pressed in the direction substantially opposite to the protruding direction of the printing wire. A second piezoelectric element fixed to the fixing member is provided so as to press the elastic member in substantially the same direction as the protruding direction of the printing wire when the second piezoelectric element is expanded.

INDUSTRIAL APPLICATION FIELD OF THE INVENTION The present invention relates to a piezoelectric hammer constituting a print head of a wire dot printer.

A wire dot printer uses a printing hammer having a plurality of thin wires to strike a platen through printing paper and an ink ribbon, thereby forming characters and figures on the printing paper as a group of points. Simultaneous copying is possible, and running costs are low because any type of printing paper can be used.
It is widely used as an output device for office automation equipment and personal computers.

The print head of a wire dot printer requires a highly reliable printing hammer that will not be damaged due to the tip of the wire getting caught even when various types of printing paper are used. Further, as devices become smaller and lighter, it is desired that the hammer section itself be made more compact. Furthermore, with the remarkable increase in the amount of information, there is a strong desire to increase the printing speed.

Conventional technology Most printing hammers used in conventional wire dot printers are electromagnetic hammers, which use the electromagnetic force generated by passing a current through a coil to move a spring-charged print head attracted by a permanent magnet. A hammer that prints by canceling the attractive force of a magnet, and a printing wire that is integrated with the coil by moving the coil using the electromagnetic force generated by energizing a coil in a magnetic field. Hammers etc. are the mainstream. However, it can be said that the technology of these electromagnetic hammers has already entered the mature stage, and it is becoming difficult to expect the printing speed to increase any further.

Recently, printing hammers using piezoelectric elements have been developed and some of them have been commercialized to increase speed. In particular, the multilayer piezoelectric element itself has high responsiveness and generates a high force, so it can be said to be suitable for high-speed printing.

Here, the piezoelectric element refers to an element constructed using a piezoelectric ceramic (piezoelectric ceramic) as a material, and this piezoelectric ceramic uniformizes the direction of spontaneous polarization in random directions by applying a high electric field. It only becomes piezoelectric when it can be aligned in one direction, that is, when it is polarized. This piezoelectricity refers to the property that when strain due to force and acceleration is applied, a voltage is generated (piezoelectric effect), and conversely, when a voltage is applied, strain is generated (inverse piezoelectric effect). As the ceramic material for the element, a PZT-based ceramic having a perovskite crystal structure is often used. That is, Pb (Zr, Ti)0, system (P ZT),
P b T IO3 system (PT), (Pb, la) (
Zr, Ti)03 series (PLZT), etc. Piezoelectric elements are manufactured by laminating these materials by a green sheet method, which is an application of the manufacturing method for multilayer capacitors, or a green sheet method, which is an application of the integral firing method, or a body firing method, using these materials.

The principle of the piezoelectric element will be explained with reference to FIG.

When a voltage is applied to the polarized piezoelectric ceramic 100,
As shown in Fig. 12, an elongation strain (longitudinal effect) occurs in the same direction as the polarization direction A, and a contraction strain (transverse effect) occurs in the perpendicular direction. Approximately twice as much distortion occurs under voltage.

A multilayer piezoelectric element utilizes the distortion caused by this piezoelectric longitudinal effect. Such a piezoelectric ceramic 100 is
As shown in the figure, when a plurality of layers are electrically stacked in parallel, the total displacement ΔT is the sum of the displacement Δt of each element.

Next, the structure of the multilayer piezoelectric element will be explained with reference to FIG. 14. The piezoelectric element has a uniform layer 10 along the driving direction.
1 and a protective layer 102.

In addition, as shown in FIG. 14, depending on the element, a layer made of piezoelectric ceramic having a thickness approximately twice that of the piezoelectric ceramic of the uniform layer is used as a buffer between the uniform layer 101 and the protective layer 102. Some are provided with a uniform layer 103. The uniform layer 101 is constructed by alternately laminating piezoelectric ceramic layers with a thickness of about 100 μm and internal electrode layers 105 made of a silver-palladium alloy, and serves as a piezoelectrically active portion. The protective layer 102 is made of piezoelectric ceramic with a thickness of about 1 mm, and since no electrodes are provided, it is a functionally inactive part. The internal electrode layer 105 is exposed on the side surface parallel to the driving direction of the element, and for electrical connection between the internal electrodes, after forming an insulating film 106 every other layer on the internal electrode 105 exposed in advance, An external electrode 104 is placed thereon. External electrode 104
A lead wire 107 is soldered to.

However, in this laminated piezoelectric element, the displacement direction dimension is approximately 10
When a voltage of 100 V is applied using a pressure-N element, the amount of displacement is about 5 to 6 μm. On the other hand, since the wire stroke of a wire dot printer requires about 0.4 layers, the amount of displacement can be expanded by 30 to 50 times using a two-film actuation mechanism using a hinge or a mechanism that fleet-writes a movable body. Therefore, it is necessary to obtain a desired wire stroke, and conventionally, the desired wire stroke has been obtained using a configuration as shown in FIGS. 15 and 16.

In the figure, 111 is a hammer base (elastic member), and one end of the hammer base 111 is fixed to a fixed member 114 made of a rigid body.The other end of the hammer base 111 is attached in the longitudinal direction of the hammer base 1. One end of the printing wire 112 is fixed in a direction perpendicular to the printing wire 112. 113 is a piezoelectric element, and one end of the piezoelectric element 113 is fixed to a fixing member 114.
Its tip is attached to the hammer base 111 so that the other end presses the hammer base 111 when the voltage is applied and the hammer base 111 is expanded.
1.

If the ratio of the dimension from the fixed end of the hammer base 111 to the pressure contact part of the piezoelectric element 113 and the dimension from the fixed end to the attachment part of the printing wire 112 is l:n (n>1), then Hammer base 11 for displacement △X
The displacement amount of the free end of the piezoelectric element 113 is n·ΔX, and this lever ratio is used to enlarge the minute displacement amount of the piezoelectric element 113.

However, when a pulse voltage is applied to the piezoelectric element 113, the piezoelectric element 113 expands, which pushes the hammer base 111 and expands the amount of displacement of the piezoelectric element 113, so that the piezoelectric element 113 is guided by the wire guide 118. The printing wire 112 protrudes and hits the platen 117 through the ink ribbon 115 and printing paper 116, and the ink on the ink ribbon 115 is transferred to the printing paper 116. Then, the printing wire 112 is pulled back to the initial position by the repulsive force when the printing wire 112 hits the platen and the restoring force of the hammer base 111, and is ready for the next voltage application.

Problems to be Solved by the Invention Conventionally, by using a piezoelectric hammer having such a configuration, a minute displacement of the piezoelectric element was magnified to obtain a predetermined wire stroke. However, the displacement magnification mechanism with the conventional configuration relies on the lever ratio of the distance from the fixed end of the printing hammer to the joint with the piezoelectric element and the distance from the fixed end to the free end of the hammer, so it is difficult to increase the magnification rate. In order to do this, the lever inevitably becomes longer and larger, and the longer printing hammer lowers its natural frequency, which hinders high-speed printing.

In addition, in the conventional configuration, in order to increase the magnification ratio, in addition to the above, it is possible to increase the voltage applied to the piezoelectric element, or to use a large piezoelectric element to increase the amount of displacement. An increase in the applied voltage is undesirable from the viewpoint of safety, and the use of a large piezoelectric element cannot be used because it becomes an obstacle to miniaturizing the device and increases costs.

The present invention has been made in view of these points, and an object thereof is to provide a piezoelectric hammer that is small in size and has a large wire stroke.

Means for Solving the Problems will be explained with reference to the principle configuration diagram of the present invention shown in FIG.

A printing wire 2 is attached to the other end of the elastic member 1 whose one longitudinal end is fixed to the fixing member 5 so as to be approximately perpendicular to the longitudinal direction of the elastic member 1. and,
The first piezoelectric element 3 has one end pressed against the elastic member 1 and the other end fixed to the fixing member 5. When the first piezoelectric element 3 is expanded, the elastic member ) is provided so as to be pressed in a direction roughly opposite to that of the Furthermore, −
One end is pressed into contact with a portion of the elastic member 1 between the attachment part of the printing wire 2 and the pressure contact part of the first piezoelectric element 3, and the other end is connected to the fixing member 5.
A second piezoelectric element 4 fixed to is provided so as to press the elastic member 1 in substantially the same direction as the protruding direction of the printing wire 2 when the second piezoelectric element 4 is expanded. Note that 6 is a wire guide for linearly protruding the printing wire 2.

According to a preferred configuration of the present invention, the drive pulse oscillation circuit 8 outputs a pulse-like voltage waveform based on the printing command signal 7, which is amplified by the high-speed amplifier circuit 9, and the first piezoelectric element 3 and the second A pulsed voltage waveform is applied to the piezoelectric element 4. Since piezoelectric elements generally have good responsiveness, they can make steep changes in response to the application of a pulsed voltage, and at the same time, the generated force also changes in a pulsed manner. By applying a pulsed voltage to the first and second piezoelectric elements 3 and 4, the displacement of the tip of the printing wire 2 can be increased several times as compared to a static voltage application state.

Further, by setting the distance between the first piezoelectric element 3 and the second piezoelectric element 4 to about 3 seconds to about 5 mm, the displacement magnification rate can be increased.

Furthermore, it is desirable to set the mounting position and drive frequency of the second piezoelectric element 4 so that the natural frequency of the elastic member 1 matches the drive frequency of the first and second piezoelectric elements 3.4.

For production The operation of the present invention will be explained with reference to FIG.

Figure (A) shows the case where a voltage is applied only to the first piezoelectric element 3, and as the first piezoelectric element 3 expands in the direction of the arrow, the elastic member 1 deforms and the printing wire 2 It is shown that it stands out.

(B) shows the case where a voltage is applied only to the second piezoelectric element 4, which has almost the same effect as the conventional structure described with reference to FIGS. 15 and 16.

2nd r! ! J(C) shows the case where voltage is applied to both the first piezoelectric element 3 and the second piezoelectric element 4 at the same time, (
It is shown that the effects of A) and (B) are combined, and the elastic member 1 is greatly deformed.

That is, as the first piezoelectric element 3 extends in the direction of arrow C, the elastic member 1 deforms as in (A), and in addition, as the second piezoelectric element 4 extends in the direction of arrow C, the elastic member 1 deforms further. The elastic member 1 is deformed similarly to (B).

As described above, according to the piezoelectric hammer of the present invention, since the elastic member 1, whose one end is fixed, receives forces in opposite directions simultaneously by the two piezoelectric elements 3.4, the amount of deformation of the elastic member 1 is smaller than that of the conventional structure. This makes it possible to obtain a large wire stroke and downsize the device. Furthermore, since the elastic member 1 can be shortened, the natural frequency of the elastic member can be increased, making it possible to cope with higher speeds. Furthermore, since the voltage applied to the piezoelectric element can be kept low, safety is also excellent.

Embodiments Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 3 is a perspective view showing a part of a wire dot printer to which the present invention is applied, FIGS. 4 and 5 are diagrams for explaining the internal structure of the print head, FIG. 4 is a front view, and FIG. The figure is a partially omitted sectional view seen from the side.

Reference numeral 10 denotes a print head, and both ends of the print head 10 are integrally fixed to a shuttle 13 that is slidably guided by guides 812 supported by support members 11.11. A part of an endless belt 16 wound around pulleys 14 and 15 is fixed to the shuttle 13.
5 is rotationally driven by a motor 17, so that the print head 10 is swung left and right. An encoder 18 is attached to the motor 17 to detect the amount of rotation thereof. 19 is a platen, 20 is a printing paper, 2
1 is an ink ribbon.

Referring to FIGS. 4 and 5, one end of 24 hammer bases 23 is fixed toward the center of each fixed member 22 made of a rigid body.

As shown in FIG. 5, one end of a printing wire 24 is fixed to the free end (other end) of the hammer base 23 in a direction perpendicular to the longitudinal direction of the hammer base 23.

25 and 26 are laminated piezoelectric elements; one end of the piezoelectric element 25 is fixed to the fixing member 22, and the other end is provided in pressure contact with the vicinity of the center of the hammer base 23. One end of the piezoelectric element 26 is fixed to the fixing member 22, and the other end is provided in pressure contact with a portion of the hammer base 23 between the pressure contact part of the piezoelectric element 25 and the fixed end. Although omitted in FIG. 5, this piezoelectric element 2
5.2N! 21: Provided for each hammer base 23. A backstop 27 made of an elastic body is provided on the back surface of the free end of the hammer base 23. The piezoelectric elements 25 and 26 are constructed by laminating thin PZT ceramic material in multiple layers as shown in FIG.

Thus, a position signal 29 is obtained from the encoder signal 28 of the encoder 18, and a motor drive signal 3 is obtained from this position signal 29.
0 is generated and the driver circuit 31 performs feedback control on the motor 17 to move the shuttle 13 left and right. On the other hand, a print command signal 32 based on the position signal 29 and print data etc. is input to a print control circuit 33, and the pulse oscillation circuit 3 is controlled by this print control circuit 33.
4, a pulsed voltage is generated, this pulsed voltage is amplified by the high speed amplifier circuit 35, and the pulsed voltage is simultaneously applied to predetermined piezoelectric elements 25 and 26 of the print head 10. When a pulse voltage is applied to the piezoelectric elements 25 and 26, the hammer base 23 moves iJl, and the printing wire 24 fixed to the tip of the hammer base 23 is guided by a hammer guide (not shown) and protrudes in the direction of the arrow d (fifth figure). As a result, the tip of the printing wire 24 hits the platen 19 via the ink ribbon 21 and the printing paper 20, and the ink ribbon
1 of ink is transferred onto printing paper 20.

Then, the printing wire 24 is pulled back by the repulsive force when the printing wire 24 hits the platen 19 and the restoring force of the hammer base 23, and is quickly braked by the backstop 27 to prevent residual vibration of the hammer base 23. , to prepare for the next voltage application.

According to this embodiment, the print head 10 is driven using a piezoelectric hammer having two piezoelectric elements 25 and 26 so that the extension directions of one hammer base 23 to which a print wire 24 is fixed repel each other. Because of this configuration, the amount of deformation of the hammer base 23 can be increased, and the stroke of the printing wire 24 can be increased compared to the conventional configuration.

In the piezoelectric hammer having the above-described configuration, the hammer base 23
The natural frequency of is determined by the supporting position of the piezoelectric elements 25 and 26 that sandwich the hammer base 23, and in particular, by moving the supporting position of the piezoelectric element 25 near the tip of the hammer base in the height direction of the hammer base 23. , its natural frequency can be easily changed. That is,
The natural frequency of the hammer base 23 can be easily set in accordance with the driving frequency based on the specifications, and as a result, high-speed printing becomes possible and displacement at low voltage can be ensured.

In the configuration of this embodiment, the stroke of the printing wire 24 is 130 μm when a pulsed voltage is applied only to the piezoelectric element 26, and 220 μm when a pulsed voltage is applied only to the piezoelectric element 25. 400μ when pulsed voltage is applied to both elements 25 and 26
It was possible to obtain a wire stroke of m.

FIG. 6 shows the results of examining the displacement characteristics of the hammer tip by actually changing the distance between the two piezoelectric elements 25 and 26 in the configuration of the above-described embodiment.

According to this result, the distance between two piezoelectric elements is approximately 311
It was observed that the displacement magnification rate becomes large when the distance is from IIo to about 5 m. Therefore, when designing a piezoelectric hammer, by setting the distance between the two piezoelectric elements to the above dimensions, it is possible to provide a piezoelectric hammer with an optimal displacement magnification ratio.

FIG. 7 shows a cross-sectional view of a second embodiment of the print head.

Since the piezoelectric elements 25 and 26 are made of ceramic, they have the drawback of being weak against impact forces and easily chipping. Therefore, as the hammer base 23 repeatedly collides with the end faces of the piezoelectric elements 25 and 26, problems arise such as damage to the end faces of the elements. Therefore, in this embodiment, a metal plate 37 is fixed to the free ends of the piezoelectric elements 25 and 26. Metal plate and 0.1
A mm-thick stainless steel plate is suitable. Further, the protective member is not limited to a metal plate, and any thin plate-like member having impact resistance and wear resistance can be used. In addition, in this embodiment, a backstop 2 is provided with a vibration absorbing material 36 attached to the back surface of the hammer base 23.
7' is provided. In this way, by adhesively fixing the thin metal plate 37 to the free end surfaces of the piezoelectric elements 25 and 26 that come into contact with the hammer base 23, it is possible to prevent the end surfaces of the piezoelectric elements from being damaged due to collisions between the hammer base and the piezoelectric elements. It is possible to extend the life of the piezoelectric hammer.

FIG. 8 shows a cross-sectional view of a third embodiment of the print head.

The piezoelectric element is generally a rectangular parallelepiped, and the negative side thereof comes into contact with the hammer base 23, so that the contact state is a surface contact. Therefore, depending on the inclination angle of the hammer base 23, the force generated by the piezoelectric element 25.26 may not be transmitted efficiently due to uneven contact, or the force generated by the piezoelectric element 25.26 may not be transmitted efficiently.
There is also a possibility that a force in a direction other than the direction of expansion and contraction of the element acts on the piezoelectric element 6 itself, and the piezoelectric element, which is weak against bending, is destroyed. Therefore, in this embodiment, a member 38 is fixed to the free end surface of the piezoelectric element 25, 26 so that the contact state with the hammer base 23 is a line contact perpendicular to the longitudinal direction of the hammer base. FIG. 9 shows a perspective view of a piezoelectric element according to this embodiment. By fixing the above-mentioned member 38 to the free end of the hammer base 25.degree. 26, damage to the piezoelectric element can be easily prevented.

FIG. 1O shows a cross-sectional view of a fourth embodiment of the print head. Due to the nature of the element, the force generated by a laminated piezoelectric element decreases in inverse proportion to the elongation from an unloaded state. Therefore, in order to generate a predetermined force, it is necessary to apply a compressive force to the element in advance. It needs to be contracted. Therefore, the piezoelectric elements 25, 26 must be set in a compressed state by the fixing member 22 and the hammer base 23. However, the hammer base 23 used cannot have a very large spring constant in order to ensure the amount of displacement, and since it is a hammer for high-speed printing, the equivalent mass at the tip of the hammer base needs to be lightweight, so it has a thin plate shape. is common. Therefore, when applying compressive force to the piezoelectric elements 25 and 26,
At the same time, the hammer base 23 is also bent, and the piezoelectric element 25
．． The hammer base 23 has a certain degree of inclination with respect to the end face of the hammer base 26. In other words, the contact state between the piezoelectric elements 25 and 26 and the hammer base 23 becomes uneven, and stress concentrates on the contact area of the piezoelectric element, causing the contact area to break or causing bending as well as compression to the piezoelectric element. Problems such as damage to the piezoelectric element arise.

Therefore, in this embodiment, a member 39.40 having an inclined surface matching the inclination angle of the hammer base 23 in the initial state where no voltage is applied to the piezoelectric element 25.26 is used to connect the piezoelectric element 25.26.
It is fixed to the free end surface of.

This prevents the piezoelectric elements 25, 26 from being damaged due to uneven contact with the hammer base 23.

FIG. 11 is an enlarged side view similar to FIG. 1 for showing in detail the main parts of the embodiment shown in FIG. 10.

Effects of the Invention As described in detail above, the present invention is configured so that the elastic member to which the printing wire is fixed is deformed by two piezoelectric elements provided so that forces act in directions that repel each other. The amount of movement of the printing wire (wire stroke) relative to the amount of displacement of the piezoelectric element can be increased, making it possible to miniaturize the device and easily realize a printing hammer that is capable of high-speed printing and has high maintainability.

[Brief explanation of drawings]

Fig. 1 is a diagram of the principle configuration of the present invention, Fig. 2 is a detailed explanatory diagram of the invention, Fig. 3 is a perspective view showing an embodiment of the invention, and Fig. 4 is a front view of the print head used in the embodiment. 5 is a side sectional view of the print head used in the example, FIG. 6 is a diagram showing the displacement characteristics of the hammer tip, FIG. 7 is a sectional view of the print head of the second embodiment, and FIG. 9 is a perspective view of a piezoelectric element; FIG. 10 is a sectional view of a fourth embodiment of the print head; FIG. 11 is an enlarged side view showing the principle of the fourth embodiment; Fig. 12 is a diagram showing the principle of a piezoelectric element, Fig. 13 is a diagram showing the principle of a laminated piezoelectric element, Fig. 14 is a perspective view showing the configuration of a laminated piezoelectric element, Figs.
FIG. 6 is an explanatory diagram of the prior art. DESCRIPTION OF SYMBOLS 1... Elastic member, 2... Printing wire, 3... First piezoelectric element, 4... Second piezoelectric element, 5... Fixing member.

Claims (1)

[Scope of Claims] (1) The other end of an elastic member (1) whose one longitudinal end is fixed to a fixed member (5) is attached in a direction approximately perpendicular to the longitudinal direction of the elastic member (1). Insert the printing wire (2
), and a first piezoelectric element (3) whose one end is pressed against the elastic member (1) and whose other end is fixed to the fixing member (5) is attached to the first piezoelectric element (3).
The piezoelectric element (3) is provided so as to press the elastic member (1) in a direction substantially opposite to the protruding direction of the printing wire (2) when the piezoelectric element (3) is expanded, and one end of the printing wire ( 2), the second piezoelectric element (4) is press-contacted to the part between the attachment part of the first piezoelectric element (3) and the pressure-contact part of the first piezoelectric element (3), and the other end is fixed to the fixing member (5). A piezoelectric hammer characterized in that the elastic member (1) is provided so as to press the elastic member (1) in substantially the same direction as the protruding direction of the printing wire (2) when the two piezoelectric elements (4) are expanded. (2) The piezoelectric hammer according to claim 1, wherein the distance between the first piezoelectric element (3) and the second piezoelectric element (4) is about 3 mm to about 5 mm. (3) The piezoelectric hammer according to claim 1, characterized in that a pulsed voltage is applied to the first piezoelectric element (3) and the second piezoelectric element (4). (4) The mounting position of the second piezoelectric element (4) and the driving frequency were set so that the natural frequency of the elastic member (1) matched with the driving frequency of the first and second piezoelectric elements (3, 4). The piezoelectric hammer according to claim 1, characterized in that: (5) Vibration absorbing means (27) on the back of the tip of the elastic member (1)
5. The piezoelectric hammer according to claim 4, wherein the piezoelectric hammers are provided in contact with each other or slightly separated from each other. (6) Elastic member (1) and first and second piezoelectric elements (3, 4
2. The piezoelectric hammer according to claim 1, wherein the contact state of the pressure contact portion with the elastic member (1) is a line contact perpendicular to the longitudinal direction of the elastic member (1). (7) A thin plate-shaped protective member (37) having impact resistance and wear resistance is fixed to the free end surfaces of the first and second piezoelectric elements (3, 4) that are in pressure contact with the elastic member (1). The piezoelectric hammer according to claim 1. (8) The first and second piezoelectric elements (39, 40) are connected to the first and second piezoelectric elements (39, 40) having an inclined surface that matches the inclination angle of the elastic member (1) in the initial state where no voltage is applied. The members (39, 40) are fixed to the free end surfaces of the two piezoelectric elements (3, 4).
2. The piezoelectric hammer according to claim 1, wherein the first and second piezoelectric elements (3, 4) are brought into pressure contact with the elastic member (1) via the elastic member (1).