Resonator

Abstract

Provided is a resonator which is characterized by comprising: a vibrating body 2A that has a length of n times (n being an integer of 1 or greater) the 1 / 2 wavelength of a longitudinal elastic vibration along a rotating central shaft direction, that is provided with an insertion hole 2a penetrating in a direction orthogonal to the central shaft such that two or more piezoelectric elements and a pair of electrode plates are arranged on the central shaft, and that is obtained by machining and integrally molding a metal, such as aluminum, titanium, or steel, and a ceramic, such as alumina or zirconia; the two or more piezoelectric elements 3; and the pair of electrode plates 4 having a wedge shape. The two or more piezoelectric elements 3 and the pair of electrode plates 4 are inserted into the insertion hole 2a, and thereby the piezoelectric elements 3 have pressure applied thereto and are fixed in the insertion hole 2a.

Description

vibrator

[0001] The present invention relates to a vibrator that achieves high coaxiality and high frequency.

[0002] Ultrasonic transducers using a piezoelectric element as an ultrasonic wave generating source are known with various configurations, and are used as power sources in the fields of acoustic communication and high-power ultrasonic waves.

[0003] In the field of acoustic communications, ultrasonic transducers are used in a wide range of applications, including medical diagnosis such as ultrasonic echoes, ultrasonic microscopes, sonar for underwater communication, fish finders, sonar for seabed exploration, etc. In this field, the frequency range used is wide, from about 20 kHz to 500 MHz, and the output power also varies widely, from several kW for fish finders to several mW for medical diagnosis.

[0004] In the field of high-power ultrasonic waves, ultrasonic vibrators are used in ultrasonic cleaning, wire bonding, ultrasonic processing machines, etc. In this field as well, the frequency range used is wide, from about 20 kHz to 1 MHz, and outputs of several kW are mainly used.

[0005] A well-known example of such an ultrasonic transducer is a bolt-clamped Langevin type ultrasonic transducer, which has a structure in which a piezoelectric element is sandwiched between metal blocks and fastened and fixed with bolts and nuts.

[0006] For example, Patent Document 1 discloses a Langevin ultrasonic transducer that is fabricated by screwing a bolt into a front steel metal block and a flange, arranging a piezoelectric element polarized in the plate thickness direction, a phosphor bronze electrode plate, a piezoelectric element polarized in the plate thickness direction, and a phosphor bronze electrode plate in that order, and screwing a rear steel metal block with a female thread onto the steel bolt.

[0007] Japanese Patent Application Laid-Open No. 2018-192467

[0008] However, the Langevin ultrasonic transducer described in Patent Document 1 is fabricated by sandwiching an electrode plate and a piezoelectric element between a front metal block and a rear metal block and screwing them onto a steel bolt. As a result, each component is placed on the rotation axis when rotating, which poses a problem in that rotating components such as an ultrasonic main shaft, which require high coaxiality, have large eccentricities and make it difficult to ensure dynamic balance.

[0009] Furthermore, when it is desired to obtain a relatively high frequency of, for example, 100 kHz or more, the wavelength becomes short, and therefore, in the Langevin ultrasonic transducer described in Patent Document 1, it is necessary to arrange a front metal block, a rear metal block, and the like at a short distance from each other, which causes a problem that the components become too small and energy loss due to friction becomes large.

[0010] The present invention has been made in view of the above problems, and has an object to provide a vibrator that can obtain high coaxiality and high frequency.

[0011] In order to achieve the above object, a first feature of the vibrator according to the present invention is that it comprises a vibrating body that is integrally molded with an insertion hole of a predetermined size, two or more piezoelectric elements, and a pair of electrode plates having a wedge shape, and by inserting the two or more piezoelectric elements and the pair of electrode plates into the insertion hole, the piezoelectric elements are pressurized and fixed within the insertion hole.

[0012] A second feature of the vibrator according to the present invention is that the vibrating body has a length n times (n is an integer of 1 or more) a half wavelength of longitudinal elastic vibration in the direction of the central axis of rotation.

[0013] A third feature of the vibrator according to the present invention is that the insertion hole is provided through the central axis in a direction perpendicular to the central axis so that the two or more piezoelectric elements and the pair of electrode plates are arranged on the central axis.

[0014] A fourth feature of the vibrator according to the present invention is that the number of the piezoelectric elements is an even number of four or more.

[0015] A fifth feature of the vibrator according to the present invention is that the insertion holes are provided in the vibrating body so that the two or more piezoelectric elements and the pair of electrode plates are arranged in a stacked manner on a line parallel to a tangent line contacting the outer periphery.

[0016] A sixth feature of the vibrator according to the present invention is that the insertion hole is provided to penetrate in a direction perpendicular to the central axis so that the two or more piezoelectric elements and the pair of electrode plates are arranged away from the central axis.

[0017] According to the vibrator of the present invention, high coaxiality and high frequency can be obtained.

[0018] FIG. 1B is a plan view of a configuration diagram of a vibrator according to Example 1 of the present invention. FIG. 1C is a cross-sectional view taken along the A-A section in FIG. 1A. FIG. 1D is a cross-sectional view of a vibrator according to Example 2 of the present invention. FIG. 1E is a cross-sectional view of a vibrator according to Example 3 of the present invention. FIG. 1F is a plan view of a configuration diagram of a vibrator according to Example 4 of the present invention. FIG. 4F is a cross-sectional view taken along the B-B section in FIG. 4A. FIG. 4G is a cross-sectional view of a vibrator according to Example 5 of the present invention, showing a state in which the vibrator is bent forward due to vibration. FIG. 4H is a cross-sectional view of a vibrator according to Example 5 of the present invention, showing a state in which the vibrator is bent backward due to vibration. FIG. 4I is a cross-sectional view of a vibration device according to Example 6 of the present invention.

[0019] Hereinafter, embodiments of the present invention will be described with reference to the drawings. The same or equivalent parts and components are designated by the same or equivalent reference numerals throughout the drawings. However, it should be noted that the drawings are schematic and may differ from the actual product. Furthermore, the drawings may include parts with different dimensional relationships and ratios.

[0020] Furthermore, the embodiments shown below are merely examples of devices that embody the technical concept of the present invention, and the technical concept of the present invention does not limit the arrangement of each component to that shown below. Various modifications can be made to the technical concept of the present invention within the scope of the claims.

[0021] 1A and 1B are diagrams illustrating the configuration of a vibrator according to a first embodiment of the present invention. Fig. 1A is a plan view, and Fig. 1B is a cross-sectional view taken along the line A-A in Fig. 1A. In the following description, the direction perpendicular to the plane of Fig. 1A is the up-down direction, and the front side of the plane of the plane is the upward direction. Furthermore, the up-down, left-right, and front-rear directions are the left-right and right-front directions in Fig. 1A.

[0022] As shown in FIGS. 1A and 1B, a vibrator 1A according to a first embodiment of the present invention is an ultrasonic vibrator, and includes a vibrating body 2A that vibrates in the left-right direction, piezoelectric elements 3a and 3b, and a pair of wedge-shaped electrode plates 4a and 4b.

[0023] The vibrating body 2A is integrally molded into a cylindrical shape centered on a central axis P1 by processing a metal such as aluminum, titanium, or steel, or a ceramic such as alumina or zirconia.

[0024] The vibrating body 2A is provided with a connecting screw hole 2b so that it can be supported rotatably around the central axis P1, and by connecting it to various tools and devices via the connecting screw hole 2b, it can be used to form, for example, medical diagnostics such as ultrasonic echoes, ultrasonic microscopes, sonar for underwater communication, fish finders, sonar for seabed exploration, etc.

[0025] The vibrating body 2A is integrally molded so that its length L1 in the direction of the central axis P1 (left-right direction) is equal to half the wavelength of the longitudinal elastic vibration, in order to resonate at a specific ultrasonic vibration frequency and obtain powerful ultrasonic vibrations from the end face of the vibrating body 2A.

[0026] The vibrating body 2A has a rectangular insertion hole 2a of a predetermined size that penetrates the vibrating body 2A in the vertical direction as shown in FIG. 1A. Piezoelectric elements 3a and 3b and a pair of electrode plates 4a and 4b are arranged in the insertion hole 2a on a central axis P1.

[0027] Specifically, piezoelectric elements 3a and 3b are inserted into insertion hole 2a from above or below. Piezoelectric elements 3a and 3b are made of zinc zirconate titanate, quartz, or the like, and vibrate when a voltage is applied. A pair of electrode plates 4a and 4b are inserted between piezoelectric element 3a and piezoelectric element 3b so that the wedge directions are opposite. Here, electrode plate 4a is inserted into insertion hole 2a in a direction tapering from top to bottom as shown in FIG. 1B , and electrode plate 4b is inserted into insertion hole 2a in a direction tapering from bottom to top as shown in FIG. 1B .

[0028] In this way, by inserting the piezoelectric elements 3a, 3b and a pair of electrode plates 4a, 4b into the insertion hole 2a of the integrally molded vibrating body 2A, the piezoelectric elements 3a, 3b are pressurized and fixed within the insertion hole 2a.

[0029] Since the piezoelectric elements 3a, 3b and the pair of electrode plates 4a, 4b are fixed in the insertion hole 2a provided in the integrally molded vibrating body 2A, when the vibrating body 2A rotates around the central axis P1, the vibrating body 2A rotates integrally with the piezoelectric elements 3a, 3b and the pair of electrode plates 4a, 4b. This makes it possible to reduce eccentricity when rotating around the central axis P1, and makes it easy to ensure dynamic balance.

[0030] Furthermore, when it is desired to obtain a relatively high frequency of 100 kHz or more using an ultrasonic vibrator, the wavelength becomes short. However, in the vibrator 1A according to Example 1 of the present invention, the vibrating body 2A is integrally molded. Therefore, unlike conventional vibrators made up of multiple components, there is no energy loss due to friction between the components, and therefore the vibrator can be made smaller, can be made compatible with a relatively high frequency of 100 kHz or more, and can obtain high vibration efficiency due to the reduced number of components.

[0031] Second Embodiment FIG. 2 is a diagram showing the configuration of a vibrator according to a second embodiment of the present invention.

[0032] 2, the vibrator 1B according to the second embodiment of the present invention is an ultrasonic vibrator and includes a vibrating body 2B that vibrates in the left-right direction, piezoelectric elements 3a to 3d, a pair of wedge-shaped electrode plates 4a and 4b, and rectangular parallelepiped electrode plates 4c to 4e. The following describes the components of the vibrator 1B that differ from those of the vibrator 1A according to the first embodiment of the present invention.

[0033] The vibrating body 2B has a rectangular insertion hole 2a of a predetermined size that penetrates in the vertical direction as shown in Figure 2, and this insertion hole 2a has piezoelectric elements 3a to 3d, a pair of wedge-shaped electrode plates 4a, 4b, and rectangular parallelepiped-shaped electrode plates 4c to 4e arranged on a central axis P1.

[0034] Specifically, piezoelectric element 3a is inserted into insertion hole 2a from the left side. Then, from the right side, electrode plate 4e, piezoelectric element 3d, electrode plate 4d, piezoelectric element 3c, electrode plate 4c, and piezoelectric element 3b are arranged in this order, with the electrode plates and piezoelectric elements alternately arranged. A pair of electrode plates 4a and 4b are inserted between piezoelectric element 3a and piezoelectric element 3b so that the wedge directions are opposite. Here, electrode plate 4a is inserted into insertion hole 2a in a direction tapering from top to bottom as shown in FIG. 2, and electrode plate 4b is inserted into insertion hole 2a in a direction tapering from bottom to top as shown in FIG. 2.

[0035] In this way, the vibrating body 2B is provided with four piezoelectric elements 3a to 3d, and thus it is possible to obtain a higher vibration output.

[0036] Here, the vibrating body 2B is provided with four piezoelectric elements, ie, the piezoelectric elements 3a to 3d, but the number of piezoelectric elements may be any number as long as it is an even number.

[0037] Third Embodiment FIG. 3 is a diagram showing the configuration of a vibrator according to a third embodiment of the present invention.

[0038] 3, a vibrator 1C according to the third embodiment of the present invention is an ultrasonic vibrator and includes a vibrating body 2C that vibrates in the left-right direction, piezoelectric elements 3a to 3b, and a pair of wedge-shaped electrode plates 4a and 4b. The following describes the components of the vibrator 1C that differ from those of the vibrator 1A according to the first embodiment of the present invention.

[0039] The vibrating body 2C is integrally molded so that its length L2 in the direction of the central axis P1 (left-right direction) is equal to one wavelength (1 / 2 wavelength x 2) of longitudinal elastic vibration in order to resonate at a specific ultrasonic vibration frequency and obtain powerful ultrasonic vibrations from the end face of the vibrating body 2C.

[0040] In this way, the vibrating body 2C has a length of one wavelength of longitudinal elastic vibration in the direction of the central axis P1 of rotation, so that a vibrator with a longer overall length can be realized.

[0041] Here, the length of the vibrating body 2C is set to one wavelength of the longitudinal elastic vibration in the direction of the central axis P1 of rotation, but is not limited to this, and may be set to a length of 3 / 2 wavelength of the longitudinal elastic vibration (1 / 2 wavelength x 3) or a length of two wavelengths of the longitudinal elastic vibration (1 / 2 wavelength x 4). In other words, the vibrating body may have a length n times (n is an integer equal to or greater than 1) the 1 / 2 wavelength of the longitudinal elastic vibration in the direction of the central axis P1 of rotation.

[0042] <Example 4> Figures 4A and 4B are configuration diagrams of a vibrator according to Example 4 of the present invention. Figure 4A is a plan view, and Figure 4B is a cross-sectional view taken along the line B-B in Figure 4A. In the following description, the direction perpendicular to the plane of the paper in Figure 4A is referred to as the up-down direction, and the front side of the paper is referred to as the upward direction. Furthermore, the up-down, left-right, and front-rear directions are referred to as the left-right and front-rear directions in Figure 4A.

[0043] 4A and 4B, a vibrator 1D according to Example 4 of the present invention is a circular ultrasonic vibrator, and includes a vibrating body 2D that vibrates in the radial direction, piezoelectric elements 3a to 3b, and a pair of wedge-shaped electrode plates 4a and 4b. Below, the configuration of the vibrator 1D that differs from that of the vibrator 1A according to Example 1 of the present invention will be described.

[0044] The vibrating body 2D is integrally molded into a circular ring shape by processing metal such as aluminum, titanium, or steel, or ceramic such as alumina or zirconia.

[0045] The vibrating body 2D is provided with an insertion hole 2a so that the piezoelectric elements 3a, 3b and the pair of electrode plates 4a, 4b are arranged on a line Q2 parallel to a tangent Q1 that contacts the outer periphery.

[0046] Specifically, piezoelectric elements 3a and 3b are inserted into the insertion hole 2a from above or below. The piezoelectric elements 3a and 3b are made of zinc zirconate titanate, quartz, or the like, and vibrate when a voltage is applied to them. A pair of electrode plates 4a and 4b are inserted between the piezoelectric elements 3a and 3b so that the wedge directions are opposite. Here, the electrode plate 4a is inserted into the insertion hole 2a in a direction tapering from top to bottom as shown in FIG. 4B , and the electrode plate 4b is inserted into the insertion hole 2a in a direction tapering from bottom to top as shown in FIG. 4B . As a result, when a voltage is applied to the piezoelectric elements 3a and 3b by the pair of electrode plates 4a and 4b, they vibrate, and the vibrating body 2D as a whole vibrates in the radial direction.

[0047] In this way, by providing an insertion hole 2a on a line Q2 parallel to a tangent line Q1 that contacts the outer periphery, and arranging piezoelectric elements 3a, 3b and a pair of electrode plates 4a, 4b on line Q2, a so-called breathing vibrator 1D that vibrates in the radial direction can be obtained.

[0048] In the fourth embodiment of the present invention, one insertion hole 2a is provided and the piezoelectric elements 3a, 3b and the pair of electrode plates 4a, 4b are arranged in the insertion hole 2a, but this is not limiting and a plurality of insertion holes 2a may be provided, which makes it possible to obtain a higher radial vibration output.

[0049] 5A and 5B are configuration diagrams of a vibrator according to Example 5 of the present invention. Fig. 5A is a plan view showing a state in which the vibrator is bent forward due to vibration, and Fig. 5B is a plan view showing a state in which the vibrator is bent backward due to vibration.

[0050] As shown in Figures 5A and 5B, a vibrator 1E according to a fifth embodiment of the present invention is an ultrasonic vibrator and includes a vibrating body 2E that vibrates in the left-right direction, piezoelectric elements 3a-3b, and a pair of wedge-shaped electrode plates 4a and 4b. The following describes the components of the vibrator 1E that differ from those of the vibrator 1A according to the first embodiment of the present invention. In Figure 5A, the unbent state of the vibrator 1E is shown as state 2E1, and the state in which both ends of the vibrator 1E are bent downward is shown as state 2E2. In Figure 5B, the unbent state of the vibrator 1E is shown as state 2E1, and the state in which both ends of the vibrator 1E are bent upward is shown as state 2E3.

[0051] The vibrating body 2E is integrally molded into a cylindrical shape centered on a central axis P1 by processing metal such as aluminum, titanium, or steel, or ceramic such as alumina or zirconia.

[0052] The vibrating body 2E is integrally molded so that its length L1 in the direction of the central axis P1 (left-right direction) is equal to half the wavelength of the longitudinal elastic vibration, in order to resonate at a specific ultrasonic vibration frequency and obtain powerful ultrasonic vibrations from the end face of the vibrating body 2E.

[0053] The vibrating body 2E has a rectangular insertion hole 2a of a predetermined size that penetrates in the vertical direction as shown in Figures 5A and 5B so that the piezoelectric elements 3a, 3b and a pair of electrode plates 4a, 4b can be arranged off the central axis P1.

[0054] In this way, by positioning the piezoelectric elements 3a, 3b and the pair of electrode plates 4a, 4b away from the central axis P1, a voltage is applied to the piezoelectric elements 3a, 3b by the pair of electrode plates 4a, 4b, causing them to vibrate, and the vibration of the entire vibrating body 2E causes both ends of the vibrating body 2E to bend forward as shown in FIG. 5A, or both ends of the vibrating body 2E to bend backward as shown in FIG. 5B, so that the entire vibrating body 2E can generate a flexural vibration.

[0055] Sixth Embodiment FIG. 6 is a diagram showing the configuration of a vibration device according to a sixth embodiment of the present invention.

[0056] 6, a vibration device 10 according to the sixth embodiment of the present invention includes the vibrator 1A according to the first embodiment of the present invention, a step horn 5, and a tool 6. The vibrator 1A is the same as the vibrator 1A described in the first embodiment, and therefore a description thereof will be omitted.

[0057] The vibrator 1A, the step horn 5, and the tool 6 are connected so as to be rotatable as a whole about a central axis P1.

[0058] The step horn 5 is formed so that its length L1 in the direction of the central axis P1 (left and right direction) is equal to half the wavelength of the longitudinal elastic vibration so as to have the same resonance frequency as the vibrator 1A.

[0059] The step horn 5 is connected to the vibrator 1A and the tool 6, and amplifies the vibration generated by the vibrator 1A and transmits it to the tool 6.

[0060] The tool 6 is, for example, one of various types of tools such as a drill or an end mill.

[0061] Although the vibrator 1A is connected to the tool 6 via the step horn 5 in this example, the present invention is not limited to this and can be connected to various mechanical devices that require vibration.

[0062] For example, it may be connected to medical equipment such as an ultrasonic catheter, an ultrasonic cleaner, an ultrasonic microscope, a sonar for underwater communication, a fish finder, a sonar for seabed exploration, a wire bonder, and the like.

[0063] Furthermore, since the vibrator 1A has a cylindrical shape, it can be rotatably supported by a bearing or the like and used as a rotating main shaft.

[0064] 1A to 1E: vibrator; 2A to 2E: vibrating body; 2a: insertion hole; 2b: connecting screw hole; 3a to 3d: piezoelectric element; 4a to 4e: electrode plate; 5: step horn; 6: tool; 10: vibration device

Claims

1. A vibrator comprising: a vibrating body that is integrally molded with an insertion hole of a predetermined size; two or more piezoelectric elements; and a pair of wedge-shaped electrode plates, wherein the two or more piezoelectric elements and the pair of electrode plates are inserted into the insertion hole, thereby pressurizing the piezoelectric elements and fixing them within the insertion hole.

2. The vibrator according to claim 1, characterized in that the vibrating body has a length n times (n is an integer of 1 or greater) half the wavelength of longitudinal elastic vibration in the direction of the central axis of rotation.

3. A vibrator according to claim 2, characterized in that the insertion hole penetrates in a direction perpendicular to the central axis so that the two or more piezoelectric elements and the pair of electrode plates are arranged on the central axis.

4. The vibrator according to claim 1, characterized in that the number of said piezoelectric elements is an even number of four or more.

5. The vibrator according to claim 1, characterized in that the insertion holes are provided in the vibrating body so that the two or more piezoelectric elements and the pair of electrode plates are arranged in a stacked manner on a line parallel to a tangent line contacting the outer periphery.

6. A vibrator according to claim 2, characterized in that the insertion hole penetrates in a direction perpendicular to the central axis so that the two or more piezoelectric elements and the pair of electrode plates are arranged away from the central axis.

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