A highly sensitive piezoelectric vibration sensor

Abstract

The present invention belongs to the field of vibration sensors and provides a piezoelectric vibration sensor with high sensitivity, which includes a housing. One end of the housing is provided with a fixing structure, and the other end of the housing is provided with an installation cavity. A positioning column is rotatably connected inside the installation cavity. An annular piezoelectric ceramic sheet is sleeved outside the positioning column. One end of the positioning column is fixedly connected with a pre-tightening screw, and a universal mass block assembly is sleeved on the pre-tightening screw. When adjusting the pre-tightening force of the universal mass block assembly on the annular piezoelectric ceramic sheet in the present invention, by pushing the push tube, the extrusion tube is separated from the side surface of the elastic ring sheet, and the middle part of the elastic ring sheet bulges, thereby releasing the restriction of the external tooth teeth on the adjusting head. At this time, the adjusting head can be rotated, and the adjusting head drives the pre-tightening screw to rotate, and then the pre-tightening force of the pre-tightening nut can be adjusted. There is no need to use tools, and it can be adjusted by hand. The device is more convenient to adjust the pre-tightening force and the operation is simpler.

Description

Technical Field

[0001] The present invention belongs to the field of vibration sensors, and particularly relates to a piezoelectric vibration sensor with high sensitivity. Background Art

[0002] During the operation of industrial equipment, vibrations of varying degrees generally exist. Severe vibrations will reduce the efficiency of the equipment and the accuracy of the actuators, damage the operating state of the machine, and even shorten the service life of the equipment. Therefore, it is necessary to detect relevant vibration information. Currently, the acquisition of vibration detection information is mainly achieved through vibration sensors. Vibration sensors mainly include piezoelectric, piezoresistive, piezocapacitive, etc., among which piezoelectric vibration sensors are the most common.

[0003] A piezoelectric vibration sensor is a sensor that measures vibration signals through the positive piezoelectric effect. When the sensor is subjected to an external force, charges will accumulate on the surfaces of the two electrodes, and the amount of charge is positively correlated with the magnitude of the external force received by the sensor.

[0004] A piezoelectric vibration sensor usually consists of a pre-tightening screw, a pre-tightening bolt, a mass block, a piezoelectric sensitive element, and a housing, etc. The pre-tightening method of the sensitive element is the pre-tightening between the pre-tightening screw and the pre-tightening bolt, and the magnitude of the pre-tightening force of the pre-tightening bolt determines the pre-tightening degree of the piezoelectric sensitive element and the mass block.

[0005] However, with the long-term use of the sensor, the pre-tightening force of the pre-tightening bolt will gradually decrease, resulting in a gap between the mass block and the piezoelectric sensitive element, leading to a decrease in the sensitivity of the sensor. At this time, the pre-tightening force of the sensor needs to be adjusted. Since the pre-tightening bolt is inside the sensor, professional tools are required for adjustment during the adjustment, and its maintenance operation is rather troublesome. Summary of the Invention

[0006] The purpose of the present invention is to provide a piezoelectric vibration sensor with high sensitivity, aiming to solve the technical problem that professional tools are required for adjusting the pre-tightening force in the prior art, resulting in rather troublesome maintenance operations.

[0007] The present invention is implemented as follows. A highly sensitive piezoelectric vibration sensor includes a housing. One end of the housing is provided with a fixing structure, and the device can be installed on an object to be measured through the fixing structure. The other end of the housing is provided with an installation cavity. A positioning column is rotatably connected inside the installation cavity. An annular piezoelectric ceramic sheet is sleeved outside the positioning column. One end of the positioning column is fixedly connected with a pre-tightening screw. A universal mass block assembly is sleeved on the pre-tightening screw. The side surface of the universal mass block assembly is in contact with the side surface of the annular piezoelectric ceramic sheet. A pre-tightening nut is also threadedly connected to the pre-tightening screw. The pre-tightening nut abuts against the universal mass block assembly. A nut holder is slidably connected inside the installation cavity. The pre-tightening nut is slidably connected inside the nut holder. The nut holder is used to prevent the pre-tightening nut from rotating relative to the housing. A pre-tightening mechanism is rotatably connected to the end of the housing. One end of the pre-tightening screw is fixedly connected with the side surface of the pre-tightening mechanism. A circuit board is arranged between the nut holder and the pre-tightening mechanism. The positive and negative electrodes of the circuit board are electrically connected to the positive and negative electrodes of the annular piezoelectric ceramic sheet through wires respectively. A wiring groove is provided on the side surface of the pre-tightening mechanism facing away from the housing. A wiring post is arranged inside the wiring groove. The circuit board is electrically connected to the wiring post through a wire.

[0008] Further technical solution: The fixing structure is a connecting head, and the connecting head is a stud.

[0009] Further technical solution: The nut holder includes a plurality of limiting guide blocks fixedly connected to the inner wall of the installation cavity. A connecting frame is slidably connected to each of the plurality of limiting guide blocks. The plurality of connecting frames are fixedly connected to the same limiting frame. A nut hole adapted to the pre-tightening nut is provided on the limiting frame. The pre-tightening nut is slidably connected inside the nut hole.

[0010] Further technical solution: The pre-tightening mechanism includes an adjusting head rotatably connected to one end of the housing. One end of the pre-tightening screw is fixedly connected with the side surface of the adjusting head. A limiting sleeve is fixedly connected to the side surface of the adjusting head close to the housing. The limiting sleeve is sleeved on one end of the housing;

[0011] In order to relatively fix the adjusting head and the housing, a self-locking mechanism is arranged between the limiting sleeve and the housing.

[0012] Further technical solution: The self-locking mechanism includes an elastic ring sheet. The elastic ring sheet is arranged on the limiting sleeve. The elastic ring sheet is made of elastic metal. Initially, the middle part of the side wall of the elastic ring sheet bulges outwards. A plurality of external teeth are arranged on the inner side wall of the elastic ring sheet. The plurality of external teeth are evenly distributed around the axis of the elastic ring sheet. An internal toothed ring is embedded on the side surface of the housing. A plurality of internal teeth are arranged on the outer side surface of the internal toothed ring. The plurality of internal teeth are evenly distributed around the axis of the housing. And the plurality of internal teeth of the internal toothed ring are respectively engaged with the plurality of external teeth.

[0013] To facilitate the adjustment of the rotation of the adjusting head, several of the outer teeth are made of elastic materials. The outer teeth can deform with the deformation of the elastic ring piece. When the middle part of the side wall of the elastic ring piece bulges outwards, the inner gear ring and the inner teeth move away from each other. Then, the end of the outer tooth contacts the end of the inner tooth. Since the end of the outer tooth has a larger deformation coefficient, when the adjusting head drives the outer tooth to rotate, the inner tooth can deflect the outer tooth to deform, so that the inner tooth can move past the outer tooth and continue to move, thereby realizing the rotation of the adjusting head;

[0014] To facilitate the inner gear ring to prevent the outer teeth from moving, the cross-sections of the outer teeth and the inner teeth are both triangular. When the elastic ring piece drives the outer teeth to approach the inner gear ring, the outer teeth are inserted between the inner teeth. Then, the end of the inner tooth contacts the root of the outer tooth. Since the root of the outer tooth is thicker and has a small deformation coefficient, the inner tooth cannot deflect the root of the outer tooth to deform, so that the inner tooth can prevent the outer teeth and the adjusting head from rotating;

[0015] To fix the limit sleeve, the self-locking mechanism further includes a locking mechanism. The locking mechanism is slidably installed on the housing. The output end of the locking mechanism is sleeved on one end of the limit sleeve. The locking mechanism is used to squeeze the protruding part of the elastic ring piece flat, so that the elastic ring piece drives the outer teeth to be inserted between the inner teeth, and then fixes the limit sleeve and the adjusting head on the housing.

[0016] Further technical solution: The locking mechanism includes a push tube sleeved on the housing. A first sliding groove is formed on the side surface of the housing. A first slider is fixedly connected to the inner side wall of the push tube. The first slider is slidably connected in the first sliding groove. An extrusion tube is fixedly connected to the side surface of the end of the push tube. The extrusion tube is sleeved on one end of the limit sleeve. The inner diameter of the extrusion tube is the same as the outer diameter of the limit sleeve;

[0017] To facilitate the pushing of the push tube, anti-slip lines are provided on the outer side surface of the push tube;

[0018] After the extrusion tube squeezes the elastic ring piece flat, in order to prevent the extrusion tube from slipping off the limit sleeve again, a compression spring is arranged between the first slider and the side wall of the first sliding groove far away from the limit sleeve.

[0019] Further technical solution: The universal mass block assembly includes a vertical mass block sleeved on a pre-tightening screw. One end of the vertical mass block abuts against an annular piezoelectric ceramic sheet. The other end of the vertical mass block is provided with a cross-shaped inclined groove. The four ends of the cross-shaped inclined groove are all inclined surfaces, and the included angle between the inclined surface and the horizontal plane is 45°. A horizontal cross-shaped mass block is arranged inside the cross-shaped inclined groove. The outer shape of the horizontal cross-shaped mass block fits the shape of the cross-shaped inclined groove. A moving hole for the pre-tightening screw to pass through is opened on the horizontal cross-shaped mass block, and the diameter of the moving hole is larger than the diameter of the pre-tightening screw.

[0020] Further technical solution: An upper electrode sheet is arranged on the top of the annular piezoelectric ceramic sheet. An upper insulating sheet is arranged between the upper electrode sheet and the housing. A lower electrode sheet is arranged at the bottom of the annular piezoelectric ceramic sheet. A lower insulating sheet is arranged between the lower electrode sheet and the universal mass block assembly. The upper electrode sheet and the lower electrode sheet are respectively connected to the positive and negative electrodes of the circuit board through wires.

[0021] Further technical solution: A gasket is arranged between the pre-tightening nut and the universal mass block assembly.

[0022] Further technical solution: Upper and lower cushion plates are respectively arranged on both sides of the circuit board.

[0023] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0024] 1. In the present invention, when adjusting the pre-tightening force of the universal mass block assembly on the annular piezoelectric ceramic sheet, by pushing the push tube, the extrusion tube is separated from the side surface of the elastic ring sheet, and the middle part of the elastic ring sheet bulges, so as to release the restriction of the external teeth on the adjusting head. At this time, the adjusting head can be rotated, and the adjusting head drives the pre-tightening screw to rotate, and then the pre-tightening force of the pre-tightening nut can be adjusted. There is no need to use tools, and it can be adjusted by hand. The device is more convenient to adjust the pre-tightening force and the operation is simpler.

[0025] 2. In the present invention, after adjusting the pre-tightening force of the pre-tightening nut, by pushing the push tube, the push tube drives the extrusion tube to extrude the elastic ring sheet, and the elastic ring sheet is extruded flat. The elastic ring sheet drives the external teeth to insert between the internal teeth, so as to fix the adjusting head, avoid the rotation of the pre-tightening screw, and then avoid the loosening of the pre-tightening nut.

[0026] 3. In the present invention, by providing a vertical mass block and a horizontal cross-shaped mass block, when the object to be measured vibrates along the axial direction of the housing, the vertical mass block and the horizontal cross-shaped mass block squeeze the annular piezoelectric ceramic sheet. When the object to be measured vibrates perpendicular to the axial direction of the housing, the object to be measured drives the horizontal cross-shaped mass block to squeeze the inclined surface of the vertical mass block, and the acting force of the horizontal cross-shaped mass block will generate components in both the horizontal and vertical directions, and the component along the axial direction of the housing will be detected by the annular piezoelectric ceramic sheet. Therefore, this device can detect the vibration of the object to be measured in any direction, and the sensitivity of this device is higher. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a schematic front view structure diagram of the whole of the present invention.

[0028] Figure 2 It is a schematic bottom view structure diagram of the whole of the present invention.

[0029] Figure 3 It is a schematic cross-sectional internal structure diagram of the whole in the present invention.

[0030] Figure 4 In the present invention Figure 3 The enlarged schematic diagram at A.

[0031] Figure 5 It is a schematic internal structure diagram of the whole in the present invention.

[0032] Figure 6 It is a schematic structure diagram of the pre-tightening mechanism at the initial time in the present invention.

[0033] Figure 7 It is a schematic structure diagram of the elastic ring sheet in the present invention.

[0034] Figure 8 It is a schematic installation structure diagram of the universal mass block assembly and the pre-tightening nut in the present invention.

[0035] Figure 9 It is a schematic cross-sectional structure diagram of the universal mass block assembly in the present invention.

[0036] Figure 10 It is a schematic structure diagram of the vertical mass block in the present invention.

[0037] In the attached drawings: 1. Connector; 2. Housing; 3. Locking mechanism; 31. Compression spring; 32. First chute; 33. Pushing tube; 34. First slider; 35. Extrusion tube; 4. Pre-tightening mechanism; 41. Inner gear ring; 42. Outer teeth; 43. Elastic ring piece; 44. Limit sleeve; 45. Adjusting head; 5. Wiring groove; 6. Wiring post; 7. Annular piezoelectric ceramic sheet; 8. Universal mass block assembly; 81. Horizontal cross mass block; 82. Vertical mass block; 83. Cross inclined groove; 9. Nut holder; 91. Connecting frame; 92. Limit guide block; 93. Limit frame; 10. Circuit board; 11. Upper insulating sheet; 12. Upper electrode sheet; 13. Lower electrode sheet; 14. Lower insulating sheet; 15. Gasket; 16. Upper backing plate; 17. Lower backing plate; 18. Pre-tightening nut; 19. Pre-tightening screw; 20. Positioning post. Detailed implementation manners

[0038] In order to make the objectives, technical solutions and advantages of the present invention more clear and understandable, the present invention will be further described in detail below with reference to the attached drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0039] The following describes in detail the specific implementation of the present invention with reference to specific embodiments.

[0040] As Figures 1 - 10 shown, a highly sensitive piezoelectric vibration sensor provided by the present invention includes a housing 2. One end of the housing 2 is provided with a fixing structure, and the device can be installed on an object to be measured through the fixing structure. The other end of the housing 2 is provided with an installation cavity. A positioning post 20 is rotatably connected inside the installation cavity. An annular piezoelectric ceramic sheet 7 is sleeved outside the positioning post 20. One end of the positioning post 20 is fixedly connected to a pre-tightening screw 19. A universal mass block assembly 8 is sleeved on the pre-tightening screw 19. The side surface of the universal mass block assembly 8 is in contact with the side surface of the annular piezoelectric ceramic sheet 7. A pre-tightening nut 18 is also threadedly connected to the pre-tightening screw 19. The pre-tightening nut 18 abuts against the universal mass block assembly 8. A nut holder 9 is slidably connected inside the installation cavity. The pre-tightening nut 18 is slidably connected inside the nut holder 9. The nut holder 9 is used to prevent the pre-tightening nut 18 from rotating relative to the housing 2. A pre-tightening mechanism 4 is rotatably connected to the end of the housing 2. One end of the pre-tightening screw 19 is fixedly connected to the side surface of the pre-tightening mechanism 4. A circuit board 10 is arranged between the nut holder 9 and the pre-tightening mechanism 4. The positive and negative electrodes of the circuit board 10 are electrically connected to the positive and negative electrodes of the annular piezoelectric ceramic sheet 7 through wires respectively. A wiring groove 5 is provided on the side surface of the pre-tightening mechanism 4 facing away from the housing 2. A wiring post 6 is arranged inside the wiring groove 5. The circuit board 10 is electrically connected to the wiring post 6 through a wire.

[0041] Insert the connecting wire into the wiring slot 5 and fixedly install the connector 1 on the object to be measured, then the vibration measurement of the object to be measured can be started.

[0042] As Figure 1 shown, a highly sensitive piezoelectric vibration sensor provided by the present invention. In this embodiment, the fixing structure is the connector 1, and the connector 1 is a stud.

[0043] As Figures 3 - 5 and Figure 8 shown, a highly sensitive piezoelectric vibration sensor provided by the present invention. In this embodiment, the nut holder 9 includes a plurality of limiting guide blocks 92 fixedly connected to the inner wall of the installation cavity. A connecting frame 91 is slidably connected to each of the plurality of limiting guide blocks 92. The plurality of connecting frames 91 are fixedly connected to the same limiting frame 93. A nut hole adapted to the pre-tightening nut 18 is formed in the limiting frame 93, and the pre-tightening nut 18 is slidably connected in the nut hole.

[0044] When rotating the pre-tightening mechanism 4, the pre-tightening mechanism 4 drives the pre-tightening screw 19 to rotate. Since the nut holder 9 restricts the rotation of the pre-tightening nut 18, the pre-tightening nut 18 can move relative to the pre-tightening screw 19, so that the pre-tightening nut 18 presses against the universal mass block assembly 8.

[0045] As Figures 1 - 7 shown, a highly sensitive piezoelectric vibration sensor provided by the present invention. In this embodiment, the pre-tightening mechanism 4 includes an adjusting head 45 rotatably connected to one end of the housing 2. One end of the pre-tightening screw 19 is fixedly connected to the side surface of the adjusting head 45. A limiting sleeve 44 is fixedly connected to the side surface of the adjusting head 45 close to the housing 2, and the limiting sleeve 44 is sleeved on one end of the housing 2;

[0046] In order to enable the adjusting head 45 to be relatively fixed to the housing 2, a self-locking mechanism is provided between the limiting sleeve 44 and the housing 2.

[0047] As Figures 3 - 7 shown, a highly sensitive piezoelectric vibration sensor provided by the present invention. In this embodiment, the self-locking mechanism includes an elastic ring piece 43. The elastic ring piece 43 is arranged on the limiting sleeve 44 and is made of elastic metal. Initially, the middle part of the side wall of the elastic ring piece 43 bulges outwards. A plurality of external teeth 42 are arranged on the inner side wall of the elastic ring piece 43. The plurality of external teeth 42 are evenly distributed around the axis of the elastic ring piece 43. An internal gear ring 41 is embedded on the side surface of the housing 2. A plurality of internal teeth are arranged on the outer side surface of the internal gear ring 41. The plurality of internal teeth are evenly distributed around the axis of the housing 2, and the plurality of internal gear rings 41 are respectively engaged with the plurality of internal teeth;

[0048] To facilitate the adjustment of the rotation of the adjustment head 45, a plurality of the external teeth 42 are made of an elastic material. The external teeth 42 can deform with the deformation of the elastic ring piece 43. When the middle part of the side wall of the elastic ring piece 43 bulges outwards, the internal tooth ring 41 and the internal teeth move away from each other, and the end of the external tooth 42 contacts the end of the internal tooth. Since the deformation coefficient of the end of the external tooth 42 is relatively large, when the adjustment head 45 drives the external tooth 42 to rotate, the internal tooth can move the external tooth 42 to deform, so that the internal tooth can move past the external tooth 42 and continue to move, thereby realizing the rotation of the adjustment head 45;

[0049] To facilitate the internal tooth ring 41 to prevent the external teeth 42 from moving, the cross-sections of the external teeth 42 and the internal teeth are both triangular. When the elastic ring piece 43 drives the external teeth 42 to approach the internal tooth ring 41, the external teeth 42 are inserted between the internal teeth, and the end of the internal tooth contacts the root of the external tooth 42. Since the root of the external tooth 42 is relatively thick and the deformation coefficient is small, the internal tooth cannot move the root of the external tooth 42 to deform, so that the internal tooth can prevent the external teeth 42 and the adjustment head 45 from rotating;

[0050] To fix the limit sleeve 44, the self-locking mechanism further includes a locking mechanism 3. The locking mechanism 3 is slidably mounted on the housing 2. The output end of the locking mechanism 3 is sleeved on one end of the limit sleeve 44. The locking mechanism 3 is used to squeeze the protruding part of the elastic ring piece 43 flat, so that the elastic ring piece 43 drives the external teeth 42 to be inserted between the internal teeth, and then fixes the limit sleeve 44 and the adjustment head 45 on the housing 2.

[0051] As Figure 1 and Figures 3 - 5 shown, a highly sensitive piezoelectric vibration sensor provided by the present invention. In this embodiment, the locking mechanism 3 includes a push tube 33 sleeved on the housing 2. A first sliding groove 32 is formed on the side surface of the housing 2. A first slider 34 is fixedly connected to the inner side wall of the push tube 33. The first slider 34 is slidably connected in the first sliding groove 32. An extrusion tube 35 is fixedly connected to the side surface of the end of the push tube 33. The extrusion tube 35 is sleeved on one end of the limit sleeve 44. The inner diameter of the extrusion tube 35 is the same as the outer diameter of the limit sleeve 44;

[0052] To facilitate the pushing of the push tube 33, anti-slip patterns are provided on the outer side surface of the push tube 33;

[0053] After the extrusion tube 35 squeezes the elastic ring piece 43 flat, to prevent the extrusion tube 35 from slipping off the limit sleeve 44 again, a compression spring 31 is provided between the first slider 34 and the side wall of the first sliding groove 32 away from the limit sleeve 44.

[0054] Push the push tube 33 upward, the push tube 33 drives the extrusion tube 35 to move, the extrusion tube 35 moves away from the side of the elastic ring piece 43, the middle of the elastic ring piece 43 bulges, thereby releasing the restriction of the external teeth 42 on the adjusting head 45. At this time, the adjusting head 45 can be rotated to adjust the pre-tightening force of the pre-tightening nut 18; slide the push tube 33 downward, the push tube 33 drives the extrusion tube 35 to extrude the elastic ring piece 43, the elastic ring piece 43 is extruded flat, and the elastic ring piece 43 drives the external teeth 42 to insert between the internal teeth, then the adjusting head 45 is fixed to prevent the pre-tightening screw 19 from rotating, and further prevent the pre-tightening force of the pre-tightening nut 18 from loosening.

[0055] As Figures 3 - 5 and Figures 8 - 10 shown, a highly sensitive piezoelectric vibration sensor provided by the present invention. In the prior art, since the annular piezoelectric ceramic sheet 7 is located on the extension line of the axis of the universal mass block assembly 8, only when the vibration direction of the object to be measured is parallel to the extension line of the universal mass block assembly 8, the universal mass block assembly 8 can generate pressure on the annular piezoelectric ceramic sheet 7, and the annular piezoelectric ceramic sheet 7 can detect the vibration of the object to be measured. The limitation of this installation method is very large, making the sensor can only detect the vibration of the object to be measured in the vertical direction. Therefore, in this embodiment, the universal mass block assembly 8 includes a vertical mass block 82, the vertical mass block 82 is sleeved on the pre-tightening screw 19, one end of the vertical mass block 82 abuts against the annular piezoelectric ceramic sheet 7, the other end of the vertical mass block 82 is provided with a cross-shaped inclined groove 83, the four ends of the cross-shaped inclined groove 83 are all inclined surfaces, the included angle between the inclined surface and the horizontal plane is 45°, a horizontal cross-shaped mass block 81 is arranged inside the cross-shaped inclined groove 83, the shape of the horizontal cross-shaped mass block 81 fits the shape of the cross-shaped inclined groove 83, and the horizontal cross-shaped mass block 81 is provided with a moving hole for the pre-tightening screw 19 to pass through, and the diameter of the moving hole is larger than the diameter of the pre-tightening screw 19.

[0056] When the object to be measured vibrates in the horizontal direction, the horizontal cross-shaped mass block 81 will squeeze the inclined surface of the cross-shaped inclined groove 83, and the force of the horizontal cross-shaped mass block 81 on the cross-shaped inclined groove 83 will be transmitted to the vertical mass block 82 in the direction perpendicular to the inclined surface. This force will form components in the horizontal and vertical directions, and the vertical component force will squeeze the vertical mass block 82, so that the vertical mass block 82 squeezes the annular piezoelectric ceramic sheet 7, then the annular piezoelectric ceramic sheet 7 can detect the vibration condition of the object to be measured in the horizontal direction, thereby making the device more sensitive.

[0057] As Figure 5As shown in the figure, a highly sensitive piezoelectric vibration sensor provided by the present invention. To avoid charge leakage on the annular piezoelectric ceramic sheet 7, which may lead to a decrease in the sensitivity of the device, in this embodiment, an upper electrode sheet 12 is provided on the top of the annular piezoelectric ceramic sheet 7, an upper insulating sheet 11 is provided between the upper electrode sheet 12 and the housing 2, a lower electrode sheet 13 is provided at the bottom of the annular piezoelectric ceramic sheet 7, a lower insulating sheet 14 is provided between the lower electrode sheet 13 and the universal mass block assembly 8, and the upper electrode sheet 12 and the lower electrode sheet 13 are respectively connected to the positive and negative electrodes of the circuit board 10 through wires.

[0058] As Figure 5 shown in the figure, a highly sensitive piezoelectric vibration sensor provided by the present invention. To increase the pre-tightening force between the pre-tightening nut 18 and the universal mass block assembly 8, in this embodiment, a gasket 15 is provided between the pre-tightening nut 18 and the universal mass block assembly 8.

[0059] As Figure 5 shown in the figure, a highly sensitive piezoelectric vibration sensor provided by the present invention. To improve the stability of the circuit board 10, in this embodiment, upper pads 16 and lower pads 17 are respectively provided on both sides of the circuit board 10.

[0060] Working principle:

[0061] Install the device on the object to be measured and insert the connecting wire into the wiring slot 5 to start detecting the vibration of the object to be measured. When the object to be measured vibrates along the axial direction of the housing 2, the object to be measured will drive the vertical mass block 82 and the horizontal cross mass block 81 to squeeze the annular piezoelectric ceramic sheet 7. When the object to be measured vibrates perpendicular to the axial direction of the housing 2, the object to be measured will drive the horizontal cross mass block 81 to squeeze the inclined surface of the vertical mass block 82. Under the action of the inclined surface, the acting force of the horizontal cross mass block 81 will generate components in both the horizontal and vertical directions, and the component along the axial direction of the housing 2 will be detected by the annular piezoelectric ceramic sheet 7. Therefore, the device can detect the vibration of the object to be measured in any direction, and the sensitivity of the device is higher;

[0062] When adjusting the pre-tightening force of the universal mass block assembly 8 on the annular piezoelectric ceramic sheet 7, push the push tube 33. The push tube 33 drives the extrusion tube 35 to move. The extrusion tube 35 moves away from the side of the elastic ring sheet 43, and the middle of the elastic ring sheet 43 bulges, thus releasing the restriction of the external tooth 42 on the adjusting head 45. At this time, the adjusting head 45 can be rotated. The adjusting head 45 drives the pre-tightening screw 19 to rotate. Since the pre-tightening nut 18 is restricted by the nut holder 9, the pre-tightening nut 18 moves relative to the pre-tightening screw 19, and then the pre-tightening force of the pre-tightening nut 18 can be adjusted. Therefore, no tools are required and it can be adjusted by hand. The device is more convenient to adjust the pre-tightening force and the operation is simpler;

[0063] Then slide the push tube 33 to drive the extrusion tube 35 to extrude the elastic ring piece 43, flatten the elastic ring piece 43. The elastic ring piece 43 drives the external teeth 42 to insert between the internal teeth, thus fixing the adjusting head 45, preventing the pre-tightening screw 19 from rotating, and then preventing the pre-tightening nut 18 from loosening.

[0064] The above are only the preferred embodiments of the present invention, and are not intended to limit the present invention. Any modifications, equivalent replacements, and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

[0065] In addition, it should be understood that although this specification is described according to embodiments, not every embodiment only contains an independent technical solution. This narrative way of the specification is only for clarity. Those skilled in the art should regard the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A highly sensitive piezoelectric vibration sensor, including a housing, one end of the housing is provided with a fixing structure, characterized in that, At the other end of the housing, an installation cavity is provided. A positioning post is rotatably connected inside the installation cavity. An annular piezoelectric ceramic sheet is sleeved outside the positioning post. One end of the positioning post is fixedly connected with a pre-tightening screw. A universal mass block assembly is sleeved on the pre-tightening screw. The side surface of the universal mass block assembly is in contact with the side surface of the annular piezoelectric ceramic sheet. A pre-tightening nut is also threadedly connected to the pre-tightening screw. The pre-tightening nut abuts against the universal mass block assembly. A nut holder is slidably connected inside the installation cavity. The pre-tightening nut is slidably connected inside the nut holder. The nut holder is used to prevent the pre-tightening nut from rotating relative to the housing. A pre-tightening mechanism is rotatably connected to the end of the housing. One end of the pre-tightening screw is fixedly connected to the side surface of the pre-tightening mechanism. A circuit board is arranged between the nut holder and the pre-tightening mechanism. The positive and negative poles of the circuit board are electrically connected to the positive and negative poles of the annular piezoelectric ceramic sheet through wires respectively. A wiring groove is provided on the side surface of the pre-tightening mechanism facing away from the housing. A wiring post is arranged inside the wiring groove. The circuit board is electrically connected to the wiring post through a wire. The pre-tightening mechanism includes an adjusting head rotatably connected to one end of the housing. One end of the pre-tightening screw is fixedly connected to the side surface of the adjusting head. A limiting sleeve is fixedly connected to the side surface of the adjusting head close to the housing. The limiting sleeve is sleeved on one end of the housing. A self-locking mechanism is arranged between the limiting sleeve and the housing. The self-locking mechanism includes an elastic ring sheet. The elastic ring sheet is arranged on the limiting sleeve. The elastic ring sheet is made of elastic metal. Initially, the middle part of the side wall of the elastic ring sheet bulges outwards. A plurality of external teeth are arranged on the inner side wall of the elastic ring sheet. The plurality of external teeth are evenly distributed around the axis of the elastic ring sheet. An internal toothed ring is embedded on the side surface of the housing. A plurality of internal teeth are arranged on the outer side surface of the internal toothed ring. The plurality of internal teeth are evenly distributed around the axis of the housing. And the plurality of internal teeth are respectively engaged with the plurality of external teeth. The plurality of external teeth are all made of elastic materials. The cross sections of the external teeth and the internal teeth are both triangular. The self-locking mechanism further includes a locking mechanism. The locking mechanism is slidably installed on the housing. The output end of the locking mechanism is sleeved on one end of the limiting sleeve. The locking mechanism is used to squeeze the bulging part of the elastic ring sheet flat.

2. The highly sensitive piezoelectric vibration sensor according to claim 1, characterized in that, The fixing structure is a connecting head.

3. The highly sensitive piezoelectric vibration sensor according to claim 1, characterized in that The nut holder includes a plurality of limiting guide blocks fixedly connected to the inner wall of the installation cavity. A connecting frame is slidably connected to each of the plurality of limiting guide blocks. The plurality of connecting frames are fixedly connected to the same limiting frame. A nut hole adapted to the pre-tightening nut is provided on the limiting frame. The pre-tightening nut is slidably connected in the nut hole.

4. The highly sensitive piezoelectric vibration sensor according to claim 1, characterized in that, The locking mechanism includes a push tube sleeved on the housing. A first sliding groove is provided on the side surface of the housing. A first sliding block is fixedly connected to the inner side wall of the push tube. The first sliding block is slidably connected in the first sliding groove. An extrusion tube is fixedly connected to the side surface of the end of the push tube. The extrusion tube is sleeved on one end of the limiting sleeve. The inner diameter of the extrusion tube is the same as the outer diameter of the limiting sleeve. A compression spring is arranged between the first sliding block and the side wall of the first sliding groove far away from the limiting sleeve.

5. The highly sensitive piezoelectric vibration sensor according to claim 1, wherein The universal mass block assembly includes a vertical mass block. The vertical mass block is sleeved on a pre-tightening screw. One end of the vertical mass block abuts against an annular piezoelectric ceramic sheet. A cross-shaped inclined groove is formed at the other end of the vertical mass block. Four ends of the cross-shaped inclined groove are all inclined planes. The included angle between the inclined plane and the horizontal plane is 45°. A horizontal cross-shaped mass block is arranged inside the cross-shaped inclined groove. The shape of the horizontal cross-shaped mass block fits the shape of the cross-shaped inclined groove. A moving hole for the pre-tightening screw to pass through is formed on the horizontal cross-shaped mass block. The diameter of the moving hole is larger than the diameter of the pre-tightening screw.

6. The highly sensitive piezoelectric vibration sensor according to claim 1, wherein, An upper electrode sheet is arranged on the top of the annular piezoelectric ceramic sheet. An upper insulating sheet is arranged between the upper electrode sheet and the housing. A lower electrode sheet is arranged at the bottom of the annular piezoelectric ceramic sheet. A lower insulating sheet is arranged between the lower electrode sheet and the universal mass block assembly. The upper electrode sheet and the lower electrode sheet are respectively connected to the positive and negative electrodes of the circuit board through wires.

7. The highly sensitive piezoelectric vibration sensor according to claim 1, characterized in that, A gasket is arranged between the pre-tightening nut and the universal mass block assembly.

8. The highly sensitive piezoelectric vibration sensor according to claim 1, wherein Upper pads and lower pads are respectively arranged on two sides of the circuit board.

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