Vibration detector

Abstract

To provide a vibration detector including an internal element that is hardly damaged even when subjected to impulsive vibration.SOLUTION: The vibration detector comprises a housing, a substrate, a case, a detection element, a metal foil, and a sealing member. The housing includes a first opening and a second opening opened smaller than the first opening in a bottom face of the first opening. The substrate is fixed to the bottom face of the first opening and airtightly seals the second opening. The case is fixed to a rear face of the substrate, stored in the second opening, and opens on its bottom face. The detection element is fixed to the rear face of the substrate and stored in the case. The metal foil is attached to the case and covers a bottom face of the case. The sealing member seals the first opening.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a vibration detection device. [Background technology]

[0002] An example of a conventional vibration detection device is Patent Document 1. The vibration detection device of Patent Document 1 aims to improve the detection accuracy of vibrations of a target device, and includes a printed circuit board on which a vibration sensor that detects vibrations of the target device is mounted, and a sensor case that houses the printed circuit board, and the surface of the printed circuit board facing the target device abuts against the sensor case at a position on the surface that faces the vibration sensor via the printed circuit board. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2021-9131 Summary of the Invention [Problem to be solved by the invention]

[0004] When measuring vibrations in machinery and equipment, shocks can be applied to the vibration detection device, which can damage the internal elements.

[0005] Therefore, an object of the present disclosure is to provide a vibration detection device in which internal elements are less likely to be damaged even when subjected to impact vibration. [Means for solving the problem]

[0006] The vibration detection device of the present disclosure includes a housing, a substrate, a case, a detection element, a metal foil, and a sealing member.

[0007] The housing includes a first opening and a second opening at the bottom of the first opening that is smaller than the first opening. The substrate is fixed to the bottom of the first opening and seals the second opening. The case is housed in the second opening and fixed to the back surface of the substrate, with its bottom surface open. The detection element is housed in the case and fixed to the back surface of the substrate. The metal foil is attached to the case and covers the bottom surface of the case. The sealing member seals the first opening. [Effects of the Invention]

[0008] According to the vibration detection device of the present disclosure, the internal elements are less likely to be damaged even when subjected to impact vibration. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a cross-sectional view of a vibration detection device according to a first embodiment. [Figure 2] FIG. 2 is a cross-sectional view of a housing of the vibration detection device according to the first embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, embodiments of the present disclosure will be described in detail. Note that components having the same functions are assigned the same numbers, and redundant explanations will be omitted. [Example]

[0011] The structure of the vibration detection device of Example 1 will be described below with reference to Figures 1 and 2. As shown in Figure 1, the vibration detection device 1 of this example includes a housing 11, a substrate 12, a case 13, a detection element 14, a metal foil 15, a sealing member 16, and a magnet 17.

[0012] In this specification, the upward direction refers to the +z direction shown in the figure, and the downward direction refers to the -z direction shown in the figure. Furthermore, the front surface of each component refers to the surface of the component facing the +z direction, and the back surface refers to the surface of the component facing the -z direction. The direction perpendicular to the +z / -z direction, that is, the rightward direction as viewed from the front of the figure, is the +x direction, and the leftward direction as viewed from the front of the figure, is the -x direction. The direction perpendicular to both the +z / -z direction and the +x / -x direction, that is, the direction toward the back of the figure, is the +y direction, and the direction toward the front of the figure, is the -y direction.

[0013] <Case 11> 2, a first opening 111 is formed so as to penetrate through the front surface side of the housing 11. A second opening 112, which is smaller than the first opening 111, is formed so as to penetrate through the center of the bottom surface 113 of the first opening 111. However, the second opening 112 does not penetrate through to the back surface side of the housing 11.

[0014] Therefore, the housing 11 has a box-like shape with a recess including a step, with the edge portion having a first depth L1 and the center portion having a second depth L2 (>L1). The housing 11 is preferably formed from a resin material having a Young's modulus of rigidity equal to or higher than a predetermined value. By using a resin material with high rigidity for the housing 11, unnecessary resonance within the measurement range can be prevented. The back surface of the housing 11 may be provided with irregularities that match the shape of the object to be detected (object to be measured), and the periphery may be fixed with an adhesive.

[0015] <Board 12> The substrate 12 has a flat plate shape, and the peripheral edge of the rear surface thereof is fixed to the bottom surface 113 of the first opening 111 to seal the second opening 112. This makes it difficult for ambient noise to affect the inside of the second opening 112.

[0016] <Case 13> The case 13 is housed in the second opening 112 and fixed to the rear surface of the substrate 12, with a part or the whole of the bottom surface being open.

[0017] Even if an impact or high G acceleration is applied instantaneously during vibration measurement, no direct load is applied to the detection element 14 or metal foil 15, which are important components in vibration measurement, and only an indirect load is applied via the substrate 12 and case 13, so the internal elements are less likely to be damaged.

[0018] <Detection element 14> The sensing element 14 is housed in the case 13 and fixed to the back surface of the substrate 12. The sensing element 14 can be, for example, a microphone. When the sensing element 14 is a microphone, a cable for extracting the microphone output is wired to the substrate 12, and a circuit for amplifying the microphone output is provided. When the sensing element 14 is a microphone, there is an advantage in that costs can be reduced.

[0019] The detection element 14 may also be a combination of a light-emitting element that emits reference light and a light-receiving element, and the vibrational displacement of the metal foil 15 may also be detected optically.

[0020] <Metal foil 15> The metal foil 15 is attached to the rear surface of the case 13 and covers the bottom surface of the case 13. The metal foil 15 may be formed by laminating or coating a resin film with the metal foil.

[0021] The vibration detection device 1 of this embodiment can be applied to any physical phenomenon that generates vibrations in the metal foil 15. For example, by selecting a magnetic material for the metal foil 15 or by laminating or coating it, it is possible to detect changes in an external magnetic field.

[0022] Using metal foil 15 as the diaphragm increases its strength and makes it less susceptible to breakage. Furthermore, using metal foil 15 for the diaphragm allows the resonant frequency to be set high even in the foil shape, and a certain level of sensitivity can be obtained for vibrations in a frequency band lower than the resonant frequency. Furthermore, because metal foil 15 is lightweight, it is sufficiently displaced by indirect vibrations via housing 11, substrate 12, and case 13, ensuring sensitivity.

[0023] It is preferable that the metal foil 15 is fixed to the case 13 by welding. This is because the metal foil 15 can be firmly fixed to the case 13 by welding, thereby increasing durability against impacts and the like.

[0024] <Sealing member 16> The sealing member 16 is filled from the front surface side of the housing 11 to seal the first opening 111. The second opening 112 is sealed by the substrate 12, and therefore the sealing member 16 is not filled therein.

[0025] The sealing member 16 is preferably made of a material having a hardness classified as hard rubber, or a material having a hardness of 80 or more on the Shore D scale.

[0026] Even if an impact is applied to the vibration detection device 1, the sealing member 16 absorbs the load on the detection element 14 and metal foil 15, making the device less likely to break. The sealing member 16 also further attenuates ambient noise, reducing the impact on the detection element 14. The sealing member 16 also suppresses the generation of unnecessary resonance modes in the housing 11 and the substrate 12. Because the substrate 12 is sealed with the sealing member 16, the vibration detection device 1 can be made waterproof and dustproof.

[0027] <Magnet 17> As shown in FIG. 1, it is preferable to configure the housing 11 so that it includes a magnet 17 for connection with the object to be detected (object to be measured) on a surface (back or side) different from the surface (front) on which the first opening 111 is provided.

[0028] As a structure other than a magnet, for example, the housing 11 may include a female thread structure or a male thread structure for connecting to the object to be detected (object to be measured) on a surface (back surface or side surface) different from the surface (front surface) on which the first opening 111 is provided.

[0029] The magnet 17, the female screw structure, and the male screw structure do not have to be separate parts from the housing 11, but may be formed as an integral part.

[0030] The magnet 17, the female screw structure, and the male screw structure allow the vibration detection device 1 to be easily attached to the object to be detected (object to be measured).

[0031] <First and second sealed spaces 18, 19> As described above, the second opening 112 is sealed by the substrate 12. The second opening 112 is divided into a first sealed space 18 and a second sealed space 19.

[0032] The first sealed space 18 is inside the case 13 and is a space surrounded by the substrate 12, the case 13, and the metal foil 15. The sensing element 14 is disposed in the first sealed space 18.

[0033] The second sealed space 19 is outside the case 13 and is a space surrounded by the housing 11, the substrate 12, the case 13, and the metal foil 15.

[0034] <Operation principle of the detection element 14> When the bottom surface of housing 11 of vibration detection device 1 is fixed to an object to be detected (object to be measured), vibrations of the object to be detected (object to be measured) are transmitted to metal foil 15 via housing 11, substrate 12, and case 13. When metal foil 15 is displaced by the vibration, a pressure change occurs in first sealed space 18. The pressure change occurring in first sealed space 18 can be detected by detection element 14.

Claims

1. a housing including a first opening and a second opening at a bottom surface of the first opening, the second opening being smaller than the first opening; a substrate fixed to a bottom surface of the first opening to seal the second opening; a case accommodated in the second opening and fixed to the rear surface of the substrate, the case having an open bottom; a detection element accommodated in the case and fixed to the rear surface of the substrate; a metal foil attached to the case and covering the bottom surface of the case; a sealing member that seals the first opening Vibration detection device.

2. The vibration detection device according to claim 1, The metal foil is Welded to the case Vibration detection device.

3. The vibration detection device according to claim 1, The sealing member is It is a material with a hardness that is classified as hard rubber. Vibration detection device.

4. The vibration detection device according to claim 1, The sealing member is The material has a Shore D hardness of 80 or more. Vibration detection device.

5. The vibration detection device according to claim 1, The sensing element is It is a microphone Vibration detection device.

6. The vibration detection device according to claim 1, The sensing element is A pair of a light-emitting element that emits reference light and a light-receiving element Vibration detection device.

7. The vibration detection device according to claim 1, The housing includes: Made of resin with a Young's modulus of a specified value or higher Vibration detection device.

8. The vibration detection device according to claim 1, a magnet is provided on a surface of the housing different from a surface on which the first opening is provided; Vibration detection device.

9. The vibration detection device according to claim 1, The housing includes a female screw structure on a surface different from the surface on which the first opening is provided. Vibration detection device.

10. The vibration detection device according to claim 1, A male screw structure is provided on a surface of the housing different from the surface on which the first opening is provided. Vibration detection device.

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