Double-ring shear type acceleration sensor and forming method thereof

Abstract

The invention discloses a double-ring shear type acceleration sensor and a forming method thereof, and belongs to the field of sensors. The sensor comprises a base, an annular mass block, a first piezoelectric ring, a second piezoelectric ring, an upper cover and a connector, the base comprises a bottom plate, an outer annular surrounding plate and an inner annular surrounding plate, the outer annular surrounding plate and the inner annular surrounding plate are coaxially arranged, a second threaded hole is formed in the outer annular surrounding plate, and the connector is installed in the second threaded hole and is in threaded fit with the second threaded hole; a first annular boss and a first annular positioning step are arranged on the outer annular face of the inner annular surrounding plate, and a second annular boss and a second positioning step are arranged on the inner annular face of the outer annular surrounding plate. The first piezoelectric ring and the second piezoelectric ring are polarized in the same direction in the axial direction. The double-layer annular nested structure ensures the lateral bending resistance of the sensor, and the lightweight design increases the bandwidth of the sensor. The structure center penetrating type mounting hole can ensure tight connection between the sensor and an object to be detected, so that the detection precision of the acceleration sensor can be improved.

Description

Technical Field

[0001] The invention belongs to the technical field of sensors, and in particular relates to a double-annular shearing acceleration sensor and a forming method thereof. Background Art

[0002] Accelerometers, which measure the acceleration of an object, are widely used in health monitoring applications such as aircraft engines and nuclear power plants. Because these applications expose them to strong electromagnetic interference, radiation, shock, and high temperatures, they must meet specific requirements for resistance to strong shock, radiation, and extreme temperatures.

[0003] Currently, the most commonly used acceleration sensors are compression sensors, which include a base, a piezoelectric element, and a mass. The piezoelectric element is placed on the base, and the mass is connected to the base, pressing the piezoelectric element against the base surface. With this structure, when the acceleration sensor moves as a whole, the mass applies pressure to the piezoelectric element, allowing the piezoelectric element to detect the pressure applied by the mass and then calculate the acceleration based on the pressure. However, because the mass, piezoelectric element, and base in this acceleration sensor are stacked in sequence, the mass has poor lateral stiffness. Therefore, when the mass moves, it is prone to lateral displacement, causing significant lateral interference to the piezoelectric element, thereby affecting the detection accuracy and sensitivity of the piezoelectric element and, consequently, the detection accuracy and sensitivity of the acceleration sensor. Summary of the Invention

[0004] In order to solve the above problems existing in the prior art, the present invention provides a dual-ring shear-type acceleration sensor and a forming method thereof. The technical problem to be solved by the present invention is achieved through the following technical solutions:

[0005] In a first aspect, the present invention provides a dual-annular shear-type accelerometer, comprising a base, an annular mass, a first piezoelectric ring, a second piezoelectric ring, an upper cover, and a joint. The base comprises a bottom plate, an outer annular plate, and an inner annular plate. The outer annular plate and the inner annular plate are coaxially arranged. A second threaded hole is provided on the outer annular plate. The joint is installed in the second threaded hole and threadedly engaged with the second threaded hole. The bottom plate, the outer annular plate, and the inner annular plate together form a receiving cavity.

[0006] A first annular boss and a first annular positioning step are provided on the outer annular surface of the inner annular enclosure, a second annular boss and a second positioning step are provided on the inner annular surface of the outer annular enclosure, the center hole of the inner annular enclosure is a first threaded hole, a center through hole is provided on the upper cover, and the first threaded hole and the center through hole together constitute a mounting hole;

[0007] The inner ring surface of the first piezoelectric ring is bonded to the first annular boss, and the first piezoelectric ring is placed on the first annular positioning step. The outer ring surface of the second piezoelectric ring is bonded to the second annular boss, and the second piezoelectric ring is placed on the second annular positioning step. The annular mass block is sleeved and bonded between the first piezoelectric ring and the second piezoelectric ring.

[0008] In one embodiment of the present invention, the material of the first piezoelectric ring and the second piezoelectric ring is piezoelectric ceramic, and the piezoelectric material of the piezoelectric ceramic is one of lead zirconate titanate ceramic, bismuth layered structure ceramic, potassium sodium niobate and bismuth scandate-lead titanate.

[0009] In one embodiment of the present invention, the first piezoelectric ring and the second piezoelectric ring are both axially polarized and have the same polarization direction.

[0010] In one embodiment of the present invention, the thickness and height of the first annular positioning step and the second annular positioning step are equal, and the thickness and height of the first annular boss and the second annular boss are equal.

[0011] In one embodiment of the present invention, the cross-section of the annular mass is T-shaped.

[0012] In one embodiment of the present invention, the annular mass block and the first piezoelectric ring are bonded together by high-temperature conductive adhesive, and the annular mass block and the second piezoelectric ring are bonded together by high-temperature conductive adhesive.

[0013] In one embodiment of the present invention, the inner ring surface of the first piezoelectric ring is bonded to the outer ring surface of the inner ring plate using high-temperature conductive adhesive, and the outer ring surface of the second piezoelectric ring is bonded to the inner ring surface of the outer ring plate using high-temperature conductive adhesive.

[0014] In one embodiment of the present invention, the top of the outer annular enclosure is provided with a connecting internal thread and a step, the outer peripheral surface of the upper cover is provided with a connecting external thread, and the upper cover is connected to the base through the connecting external thread and the connecting internal thread.

[0015] In a second aspect, the present invention provides a forming method for a dual-annular shear-type accelerometer, which is applied to the dual-annular shear-type accelerometer provided in the above scheme. The dual-annular shear-type accelerometer includes a base, an annular mass, a first piezoelectric ring, a second piezoelectric ring, an upper cover, and a joint. The base includes a bottom plate, an outer annular plate, and an inner annular plate. The bottom plate, the outer annular plate, and the inner annular plate together form a receiving cavity. The method includes:

[0016] Step 1: Based on the performance indicators required for the dual-annular shear piezoelectric accelerometer, preliminarily determine the process route, select the materials for the base, annular mass block, first piezoelectric ring, second piezoelectric ring, upper cover, and joint, repeatedly optimize the structural parameters based on the materials of the base, annular mass block, first piezoelectric ring, second piezoelectric ring, upper cover, and joint until the simulation results meet the expected performance indicators. Then, design and prepare each component based on the structural parameters obtained by simulation;

[0017] Step 2: Complete the axial polarization of the piezoelectric ring, then grind and remove the end surface electrodes, apply conductive silver glue on the outer ring surface of the first piezoelectric ring and the inner ring surface of the second piezoelectric ring, and embed the first piezoelectric ring and the second piezoelectric ring on the inner and outer ring surfaces of the annular mass block respectively and solidify them to obtain the sensor sensitive element;

[0018] Step 3: Apply conductive silver glue on the inner ring surface of the first piezoelectric ring and the outer inner ring surface of the second piezoelectric ring, and insert the sensor sensitive element between the outer annular plate and the inner annular plate;

[0019] Step 4: Glue the wire to the annular mass block with conductive silver glue, and screw the connector into the second threaded hole of the outer and middle annular panels on the bottom.

[0020] Step 5: Install the top cover onto the base.

[0021] In one embodiment of the present invention, step one specifically includes:

[0022] The simulation was performed using COMSOL Multiphysics software developed by the Swedish COMSOL Group;

[0023] Step 2 specifically includes:

[0024] The two end surfaces of the first piezoelectric ring and the second piezoelectric ring were evenly coated with conductive silver glue, and then placed in an oven for curing at a temperature of 100°C for 30 minutes;

[0025] The first piezoelectric ring and the second piezoelectric ring are placed in a silicone oil bath, and a pair of positive and negative electrode rods connected to a high-voltage DC polarization power supply are introduced to the two end surface electrodes of the first piezoelectric ring and the second piezoelectric ring;

[0026] The silicone oil bath was heated to 120°C using an electric heater. The polarization voltage was then slowly increased until the desired polarization electric field of 3 kV / mm was reached. The high voltage polarization was maintained for half an hour to complete the polarization of the first and second piezoelectric rings.

[0027] After the polarization of the first piezoelectric ring and the second piezoelectric ring is completed, the end surface electrodes of the first piezoelectric ring and the second piezoelectric ring are removed, and high-temperature conductive silver glue is applied to the outer ring surface of the first piezoelectric ring and the inner ring surface of the second piezoelectric ring. The first piezoelectric ring and the second piezoelectric ring are placed on the inverted annular mass block until the end surface of the piezoelectric ring abuts against the step of the mass block. When placing them, ensure that the polarization direction of the first piezoelectric ring is the same as that of the second piezoelectric ring. Finally, put them into an oven for curing at a curing temperature of 100°C and a curing time of 30 minutes;

[0028] Step three specifically includes:

[0029] Apply high-temperature conductive silver glue on the inner ring surface of the first piezoelectric ring and the outer ring surface of the second piezoelectric ring, bond the inner ring surface of the first piezoelectric ring to the outer ring surface of the inner ring enclosure, and bond the outer ring surface of the second piezoelectric ring to the inner ring surface of the outer ring enclosure. During bonding, ensure that the end faces of the first and second piezoelectric rings abut against the end faces of the first and second positioning steps, and place them in an oven for curing at a curing temperature of 100°C and a curing time of 30 minutes.

[0030] Step 4 specifically includes:

[0031] Apply high-temperature resistant insulating glue on the inner wall of the central through hole of the connector and dry it;

[0032] The first piezoelectric ring and the second piezoelectric ring are bonded to the annular mass block using high-temperature conductive adhesive and then put into an oven for curing;

[0033] Bond the copper or silver wire to the mass block with high-temperature conductive adhesive, apply high-temperature insulating silicone around the wire, and solidify it;

[0034] Screw the connector into the second threaded hole and lead the wire out of the connector;

[0035] Step 5 specifically includes:

[0036] Install the upper cover onto the base, bond the upper cover and the base with high-temperature conductive adhesive, and place them in an oven for curing at a temperature of 100°C for 30 minutes.

[0037] Compared with the prior art, the present invention has the following beneficial effects:

[0038] The above scheme of the present application includes a base, an annular mass block, a first piezoelectric ring, a second piezoelectric ring, an upper cover and a joint. The base includes a bottom plate, an outer annular enclosure and an inner annular enclosure. The outer annular enclosure and the inner annular enclosure are coaxially arranged. A second threaded hole is provided on the outer annular enclosure. The joint is installed in the second threaded hole and threadedly cooperates with the second threaded hole. The bottom plate, the outer annular enclosure and the inner annular enclosure together form an accommodating cavity; a first annular boss and a first annular positioning step are provided on the outer annular surface of the inner annular enclosure, a second annular boss and a second positioning step are provided on the inner annular surface of the outer annular enclosure, the center hole of the inner annular enclosure is a first threaded hole, and a center through hole is provided on the upper cover. The first threaded hole and the center through hole together constitute a mounting hole; the inner annular surface of the first piezoelectric ring is bonded to the first annular boss, the first piezoelectric ring is placed on the first annular positioning step, the outer annular surface of the second piezoelectric ring is bonded to the second annular boss, the second piezoelectric ring is placed on the second annular positioning step, and the annular mass block is sleeved and clamped between the first piezoelectric ring and the second piezoelectric ring. With this structure, when the acceleration sensor moves as a whole, the annular mass block located between the first piezoelectric ring and the second piezoelectric ring can move relative to the two, so the annular mass block can apply shear stress to the first piezoelectric ring and the second piezoelectric ring, thereby driving the first piezoelectric ring and the second piezoelectric ring to deform along their axial direction, so that the first piezoelectric ring and the second piezoelectric ring can generate a piezoelectric signal. By collecting the piezoelectric signal, the magnitude of the shear stress applied by the annular mass block can be obtained, and then the acceleration of the target object can be calculated. In the above structure of the present application, the inner annular plate, the first piezoelectric ring, the annular mass block, the second piezoelectric ring and the outer annular plate are arranged in sequence, so that the inner annular plate, the first piezoelectric ring, the second piezoelectric ring and the outer annular plate can laterally support the annular mass block, improve the lateral stiffness of the annular mass block, reduce the lateral interference to the piezoelectric element caused by the lateral displacement that is easy to occur when the mass block moves, thereby improving the detection accuracy and sensitivity of the piezoelectric element, and thus improving the detection accuracy and sensitivity of the acceleration sensor. In addition, the present application detects the shear stress of the inner and outer surfaces of the annular mass block respectively through the first piezoelectric ring and the second piezoelectric ring, thereby further improving the detection accuracy and sensitivity of the acceleration sensor.

[0039] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 is a cross-sectional view of an acceleration sensor according to an embodiment of the present invention;

[0041] Figure 2 is an exploded schematic diagram of an acceleration sensor in an embodiment of the present invention;

[0042] Figure 3 is a schematic diagram of an upper cover in an embodiment of the present invention;

[0043] Figure 4 is a schematic diagram of a first piezoelectric ring and a second piezoelectric ring in an embodiment of the present invention;

[0044] Figure 5 is a schematic diagram of a base in an embodiment of the present invention;

[0045] Figure 6 is a cross-sectional view of a base in an embodiment of the present invention;

[0046] Figure 7 is a schematic diagram of an annular mass block according to an embodiment of the present invention;

[0047] Figure 8 is a cross-sectional view of an annular mass block according to an embodiment of the present invention;

[0048] Figure 9 is a schematic diagram of a joint in an embodiment of the present invention;

[0049] Figure 10 Schematic diagram of the first six resonant modes during simulation of the acceleration sensor according to an embodiment of the present invention;

[0050] Figure 11 FIG. 4 is a frequency response curve diagram of the acceleration sensor during simulation in an embodiment of the present invention.

[0051] Figure markings: 1-base, 11-bottom plate, 12-outer annular enclosure, 121-second annular boss, 122-second annular positioning step, 123-step, 13-inner annular enclosure, 131-first annular boss, 132-first annular positioning step, 2-annular mass block, 3-first piezoelectric ring, 4-second piezoelectric ring, 5-upper cover, 6-first threaded hole, 7-connector. DETAILED DESCRIPTION

[0052] The present invention will be further described in detail below with reference to specific examples, but the embodiments of the present invention are not limited thereto.

[0053] Example 1:

[0054] See Figure 1 and Figure 2 The embodiment of the present invention provides a dual-annular shear acceleration sensor, comprising a base 1, an annular mass 2, a first piezoelectric ring 3, a second piezoelectric ring 4, an upper cover 5, and a connector 7. The base 1 is composed of a bottom plate 11 and a coaxial outer annular plate 12 and an inner annular plate 13 connected together. The outer annular plate 12 has a threaded hole, and the lead connector 7 is connected to the base 1 through the threaded hole; Figure 5 and Figure 6As shown, within the enclosed accommodating cavity, the inner annular enclosure 13 and the outer annular enclosure 12 are respectively provided with a first annular positioning step 132 and a first annular boss 131, as well as a second annular positioning step 122 and a second annular boss 121. The inner ring of the inner annular enclosure 13 is fully threaded, and this portion and the central through-hole of the upper cover 5 together form the mounting hole for the sensor. The inner annular surface of the first piezoelectric ring 3 is bonded to the annular surface of the first annular boss 131, with the outer edge of the bottom end face of the first piezoelectric ring 3 resting on the plane of the first annular positioning step 132. The inner annular surface of the second piezoelectric ring 4 is bonded to the annular surface of the second annular boss 121, with the inner edge of the bottom end face of the piezoelectric ring 4 resting on the plane of the second annular positioning step 122. The annular mass 2 is nested and bonded between the first piezoelectric ring 3 and the second piezoelectric ring 4, with the T-shaped boss of the annular mass 2 clamped to the inner edge of the top end face of the first piezoelectric ring 3 and the outer edge of the top end face of the second piezoelectric ring 4. The upper cover 5 with the through hole cooperates with the base 1 through the threads of the outer ring to form a closed space.

[0055] In some embodiments of the present application, the material of the first piezoelectric ring 3 and the second piezoelectric ring 4 can be piezoelectric ceramics. Commonly available piezoelectric materials include but are not limited to: lead zirconate titanate ceramics (Pb(Zr,Ti)O3), bismuth layered structure ceramics (such as Bi4Ti3O 12 (BIT), SrBi4Ti4O 15 (SBTi)), potassium sodium niobate ((K,Na)NbO3), bismuth scandate-lead titanate ((1-x)BiScO3-xPbTiO3), etc. For higher operating temperatures, the piezoelectric material can also be made of single crystal materials with stable high-temperature piezoelectric properties, such as YCOB (YCa4O(BO3)3). When piezoelectric elements made of bismuth scandate-lead titanate ((1-x)BiScO3-xPbTiO3) material are used in vibration and shock tests at temperatures up to 260°C.

[0056] In some embodiments of the present application, the first piezoelectric ring 3 and the second piezoelectric ring 4 are both polarized along the axial direction and have the same polarization direction. 15 Working in circular shear mode.

[0057] In some embodiments of the present application, the outer annular enclosure 12 and the inner annular enclosure 13 are coaxial, and the two are connected to the base plate 11 along their axial end faces to form an integrated structure, which requires good coaxiality and verticality to ensure the subsequent installation reliability of the annular piezoelectric element.

[0058] In some embodiments of the present application, the accommodating cavity is an annular chamber, which is surrounded by the upper surface of the base plate 11, the inner annular surface of the outer annular surrounding plate 12, the outer annular surface of the inner annular surrounding plate 13 and the lower surface of the upper cover 5.

[0059] In some embodiments of the present application, Figure 6 As shown, the outer annular plate 12 and the inner annular plate 13 in the base 1 are provided with steps and bosses, wherein the first annular positioning step 132 and the second annular positioning step 122 are the bottom layers, which are used for positioning the first piezoelectric ring 3 and the second piezoelectric ring 4 respectively; the first annular boss 131 and the second annular boss 121 are the middle layers, which constitute the accommodating space of the annular piezoelectric sheet, and the height of the first annular boss 131 and the second annular boss 121 are consistent with the height of the first piezoelectric ring 3 and the second piezoelectric ring 4. The specific structure is as shown in FIG. Figure 1 and Figure 6 As shown in the figure, the wall thickness of the top layers of the inner and outer annular panels is further reduced, thus expanding the accommodation space inside the sensor.

[0060] In some embodiments of the present application, the thickness and height of the first annular positioning step 132 and the second annular positioning step 122 are equal, and the thickness and height of the first annular boss 131 and the second annular boss 121 are equal.

[0061] In some embodiments of the present application, Figure 7 and Figure 8 As shown, the cross section of the annular mass block 2 is T-shaped, that is, positioning steps of the same thickness and height are provided on the same horizontal plane of the inner annular surface and the outer annular surface of the mass block.

[0062] In some embodiments of the present application, Figure 1 As shown, the first piezoelectric ring 3 is nested within the inner ring of the annular mass 2 until its end surface reaches the stepped surface of the inner ring of the annular mass 2. The second piezoelectric ring 4 is nested within the outer ring of the annular mass 2 until its end surface reaches the stepped surface of the inner ring of the annular mass 2. Both ring surfaces are bonded together using high-temperature conductive adhesive. The effective dimensions of the overlap between the end surfaces of all the piezoelectric rings and the stepped surface do not exceed 1 / 4 of the average radial thickness of the piezoelectric rings.

[0063] In some embodiments of the present application, when the dual piezoelectric rings, with the annular mass 2 bonded to them, are assembled into the base 1, the other end faces of the first piezoelectric ring 3 and the second piezoelectric ring 4 abut against the planes of the first annular positioning step 132 and the second annular positioning step 122, respectively. The effective dimension of the overlap between the end faces and the step planes also does not exceed 1 / 4 of the average radial thickness of the piezoelectric rings. The inner surface of the first piezoelectric ring 3 is bonded to the outer surface of the inner annular plate 13 using high-temperature conductive adhesive, while the outer surface of the second piezoelectric ring 4 is bonded to the inner surface of the outer annular plate 12 using high-temperature conductive adhesive.

[0064] In some embodiments of the present application, Figure 6As shown, the outer annular plate 12 and the inner annular plate 13 of the base 1 are respectively provided with a second annular boss 121 and a first annular boss 131. These annular surfaces are used for the coaxial nesting and bonding of the annular piezoelectric discs. Because nesting of annular piezoelectric elements requires high machining precision of the contacting parts, the introduction of the second annular boss 121 and the first annular boss 131 effectively reduces the area of ​​contact between the inner and outer annular surfaces of the piezoelectric ring and the housing during assembly, thereby reducing the overall machining difficulty of the base components and effectively reducing the base mass.

[0065] In some embodiments of the present application, the step of the annular mass block 2 and the first annular positioning step 132 and the second annular positioning step 122 of the base 1 can be used to limit the piezoelectric element during assembly, and on the other hand, can better apply shear force to the piezoelectric element when the device is working.

[0066] In some embodiments of the present application, Figure 5 、 Figure 6 As shown, the outer annular plate 12 is provided with a second threaded hole for connecting with the joint. Figure 9 The connector 7 shown is provided with external threads and is inserted into and matingly connected to the second threaded hole. After assembly, a gap exists between the end face of the connector 7 and the second piezoelectric ring 4. This design of the connector and base being separate facilitates assembly and disassembly of the connector 7 and also helps reduce the difficulty and cost of manufacturing the base and connector.

[0067] In some embodiments of the present application, Figure 5 and Figure 6 As shown, the top annular surface of the outer annular enclosure 12 is provided with connecting threads and steps 123, and the upper cover 5 is connected to the base 1 through threaded fitting. The upper cover 5 is provided with three blind holes, which can be used in conjunction with specific clamping devices for installation and removal of the upper cover. The upper cover 5 is provided with a circular through hole, the diameter of which is slightly larger than the major diameter of the first threaded hole 6 and smaller than the outer diameter of the top step of the inner annular enclosure 13, and the axis of the through hole is collinear with the axis of the first threaded hole 6. The through hole and the first threaded hole 6 together constitute the mounting hole of the sensor. The design of this central mounting hole makes it more convenient and reliable to install and connect the acceleration sensor and the device to be tested, which is beneficial to improving the installation frequency response characteristics of the sensor. In addition, by closing the accommodating cavity in the base 1 with the upper cover 5, the airtightness and electromagnetic shielding performance of the acceleration sensor can be improved.

[0068] In some embodiments of the present application, the final effect of the assembled sensor is that the inner annular enclosure 13, the first piezoelectric ring 3, the annular mass block 2, the second piezoelectric ring 4 and the outer annular enclosure 12 are arranged in sequence and coaxially, and the annular mass block 2 is located in the accommodating cavity and there is a gap between it and the upper surface of the base plate 11 and the lower surface of the upper cover 5.

[0069] In some embodiments of the present application, the annular mass 2 has a large inertia. Therefore, when the acceleration sensor as a whole moves, the annular mass 2 can generate movement relative to the first piezoelectric ring 3 and the second piezoelectric ring 4, causing shear stress to be generated on the inner surface of the first piezoelectric ring 3 and the outer surface of the second piezoelectric ring 4, thereby driving the first piezoelectric ring 3 and the second piezoelectric ring 4 to deform along their axial direction. Due to the piezoelectric effect, the piezoelectric rings generate electrical signals. Furthermore, the annular mass 2 is located between the first piezoelectric ring 3 and the second piezoelectric ring 4. When in motion, the forces acting on the two rings are opposite. Therefore, during installation, the polarization directions of the two rings are aligned, so that the outer surface of the first piezoelectric ring 3 and the inner surface of the second piezoelectric ring 4 generate piezoelectric signals of the same sign in the operating state. At the same time, the metal annular mass 2 can serve as a common electrode for the two piezoelectric rings and derive the generated electrical signal. By collecting this piezoelectric signal, the current acceleration of the sensor can be calculated.

[0070] In some embodiments of the present application, Figure 1 、 Figure 2 and Figure 9 As shown, the wires connected to the annular mass 2 can extend through the interior of the connector 7, allowing an external signal receiver to receive the piezoelectric signals from the first piezoelectric ring 3 and the second piezoelectric ring 4 through the wires. At the same time, the inner ring signal of the first piezoelectric ring 3 and the outer ring signal of the second piezoelectric ring 4 are directly led out of the outer shell of the connector 7 through the base 1.

[0071] In some embodiments of the present application, the base 1, annular mass 2, upper cover 5, and connector 7 are all made of a metal with a thermal expansion coefficient close to that of the piezoelectric material, typically TC4 titanium alloy, to ensure sensor reliability at high temperatures. The conductors can be made of pure silver or pure copper stranded wire, both of which have excellent electrical conductivity.

[0072] In the above scheme of the present application, the dual-annular shear type acceleration sensor includes a base 1, the base 1 includes a bottom plate 11, an outer annular plate 12 and an inner annular plate 13, the outer annular plate 12 is sleeved on the outside of the inner annular plate 13 and the two are coaxially arranged, the outer annular plate 12 and the inner annular plate 13 are both connected to the bottom plate 11, and the bottom plate 11, the outer annular plate 12 and the inner annular plate 13 together form an accommodating cavity; an annular mass block 2, a first piezoelectric ring 3 and a second piezoelectric ring 4 are provided in the accommodating cavity, the first piezoelectric ring 3 is sleeved on the outer ring surface of the inner annular plate 13, the second piezoelectric ring 4 is sleeved on the inner ring surface of the outer annular plate 12, and the annular mass block 2 is sleeved and glued and fixed between the first piezoelectric ring 3 and the second piezoelectric ring 4.

[0073] In the above structure of the present application, the inner annular plate 13, the first piezoelectric ring 3, the annular mass block 2, the second piezoelectric ring 4 and the outer annular plate 12 are arranged in sequence, so that the inner annular plate 13, the first piezoelectric ring 3, the second piezoelectric ring 4 and the outer annular plate 12 can all provide lateral support to the annular mass block 2, thereby improving the lateral stiffness of the annular mass block 2, reducing the lateral interference to the piezoelectric element caused by the lateral displacement of the mass block during movement, thereby improving the detection accuracy and sensitivity of the piezoelectric element, and further improving the detection accuracy and sensitivity of the acceleration sensor, and enabling the sensor to obtain a larger bandwidth. In addition, the present application adopts a double-layer piezoelectric ring. When working, the first piezoelectric ring 3 and the second piezoelectric ring 4 form an electrical parallel connection, which can increase the amount of charge signal generated by the sensor, thereby further improving the detection accuracy and sensitivity of the acceleration sensor.

[0074] Example 2:

[0075] An embodiment of the present invention provides a forming method for a dual-annular shear-type accelerometer, which is applied to the dual-annular shear-type accelerometer provided in the first embodiment above. The dual-annular shear-type accelerometer includes a base, an annular mass, a first piezoelectric ring, a second piezoelectric ring, an upper cover, and a joint. The base includes a bottom plate, an outer annular plate, and an inner annular plate. The bottom plate, the outer annular plate, and the inner annular plate together form a receiving cavity. The method includes:

[0076] Step 1: Based on the performance indicators required for the dual-annular shear-type piezoelectric accelerometer, preliminarily determine the process route, select suitable piezoelectric ceramic materials and other component materials, and repeatedly optimize the structural parameters according to the selected piezoelectric materials and sensor indicators until the simulation results meet the expected performance indicators; then, based on the structural parameters obtained by simulation, design and prepare each corresponding component.

[0077] Step 2: Complete the axial polarization of the piezoelectric ring, then grind and remove the end face electrode, apply conductive silver glue on the outer annular surface of the first piezoelectric ring and the inner annular surface of the second piezoelectric ring, and coaxially and tightly nest them on the inner and outer surfaces of the annular mass block respectively. After curing, a shear-type piezoelectric acceleration sensor sensitive element in the form of a piezoelectric double ring is formed.

[0078] Step 3: Further apply conductive silver glue on the inner and outer annular surfaces of the sensor sensitive element, tightly insert it into the vibration cavity and attach it to the inner walls of the inner and outer annular panels until it abuts the end surface of the positioning step in the vibration cavity.

[0079] Step 4: Glue the wire to the annular mass block with conductive silver glue, and then screw the connector through its external thread to the side wall of the outer annular enclosure of the base and the connection hole with the internal thread;

[0080] Step 5: The upper cover forms a thread pair with the internal thread of the base through the external thread, and the upper cover can be installed on the end of the base by screwing.

[0081] The beneficial effects of the second embodiment of the present invention and its various implementations can be analyzed with reference to the beneficial effects of the first embodiment and its various implementations, and will not be repeated here.

[0082] In some embodiments of the present application, step one specifically includes:

[0083] First, simulations were performed using COMSOL Multiphysics, developed by the Swedish COMSOL Group. Material parameters (including but not limited to density, Young's modulus, Poisson's ratio, and piezoelectric coefficient) were sourced from relevant literature. The sensor's sensitivity, frequency response, and lateral sensitivity were calculated. Secondly, the base and cover were made of TC4, the annular mass was made of TC4, and the first and second piezoelectric rings were made of BSPT ceramic. Figure 10 The first six resonance modes of the acceleration sensor simulation are shown. Figure 11 The frequency response curve of the acceleration sensor in the three-axis direction within the range of 50Hz-80kHz is shown. Figure 10 It can be seen that the first two resonance modes of the sensor are both lateral bending modes, and the fourth is the main resonance mode. The Z axis corresponds to the sensitive axis of the sensor. Combined with the results in (1), the first three orders correspond to the resonance in the lateral direction, which will strongly interfere with the Z axis signal at the corresponding resonance frequency. Overall, the upper limit of the usable frequency range of the sensor determined by the 10% deviation is 23.7kHz. The lateral crosstalk is very weak in this frequency range, and the detection accuracy and sensitivity of the acceleration sensor are high.

[0084] The second step specifically includes:

[0085] Evenly coat both end surfaces of the first piezoelectric ring and the second piezoelectric ring with conductive silver glue, and place them in an oven for curing at a temperature of 100° C. for 30 minutes;

[0086] The first piezoelectric ring and the second piezoelectric ring are placed in a silicone oil bath, and a pair of positive and negative electrode rods connected to a high-voltage DC polarization power supply are introduced to the two end surface electrodes of the piezoelectric ring;

[0087] The silicone oil bathtub was heated to 120° C. by an electric heater; the polarization voltage was then slowly increased until the required polarization electric field of 3 kV / mm was reached; the high voltage polarization was maintained for half an hour to complete the polarization of the first piezoelectric ring and the second piezoelectric ring.

[0088] After the first and second piezoelectric rings are polarized, the electrodes on their end surfaces are removed. High-temperature conductive silver glue is applied to the outer surface of the first piezoelectric ring and the inner surface of the second piezoelectric ring. The first and second piezoelectric rings are then nested onto the inverted annular mass block, ensuring that the polarization direction of the first and second piezoelectric rings align. Finally, the rings are placed in an oven for curing at 100°C for 30 minutes. This method ensures a more reliable connection between the first piezoelectric ring, the annular mass block, and the second piezoelectric ring.

[0089] Step three specifically includes:

[0090] High-temperature conductive silver glue is applied to the inner surface of the first piezoelectric ring and the outer surface of the second piezoelectric ring. The inner surface of the first piezoelectric ring is bonded to the outer surface of the inner annular plate, and the outer surface of the second piezoelectric ring is bonded to the inner surface of the outer annular plate. The two rings are then placed in an oven for curing at 100°C for 30 minutes. This method provides a more reliable connection between the first and second piezoelectric rings and the base.

[0091] Step 4 specifically includes:

[0092] Apply high-temperature resistant insulating glue on the inner wall of the central through hole of the connector and dry it;

[0093] The first piezoelectric ring and the second piezoelectric ring are bonded to the annular mass block using high-temperature conductive adhesive and then put into an oven for curing;

[0094] Bond the copper or silver wire to the mass block with high-temperature conductive adhesive, apply high-temperature insulating silicone around the wire, and solidify it;

[0095] Screw the connector into the second threaded hole and lead the wire out of the connector.

[0096] Step 5 specifically includes:

[0097] The top cover is mounted on the base, and the two are bonded together using high-temperature conductive adhesive. The adhesive is then placed in an oven and cured at 100°C for 30 minutes. This method improves the stability of the connection between the top cover and the base.

[0098] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise" and the like to indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0099] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features being referred to. Thus, a feature identified as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, "plurality" means two or more, unless otherwise specifically defined.

[0100] In the present invention, unless otherwise expressly specified or limited, the terms "mounted," "connected," "connect," "fixed," etc. should be understood broadly. For example, they may refer to fixed connection, detachable connection, or integration; mechanical connection or electrical connection; direct connection or indirect connection through an intermediate medium; internal communication between two components or interaction between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0101] The above is a further detailed description of the present invention in conjunction with specific preferred embodiments, and the specific implementation of the present invention should not be considered to be limited to these descriptions. For those skilled in the art to which the present invention belongs, several simple deductions or substitutions can be made without departing from the concept of the present invention, and all of these should be considered to fall within the scope of protection of the present invention.

Claims

1. A double-ring shear acceleration sensor, characterized in that: The invention comprises a base, an annular mass, a first piezoelectric ring, a second piezoelectric ring, an upper cover and a joint. The base comprises a bottom plate, an outer annular plate and an inner annular plate. The outer annular plate and the inner annular plate are coaxially arranged. A second threaded hole is provided on the outer annular plate. The joint is installed in the second threaded hole and is threadedly engaged with the second threaded hole. The bottom plate, the outer annular plate and the inner annular plate together form a receiving cavity. A first annular boss and a first annular positioning step are provided on the outer annular surface of the inner annular enclosure, a second annular boss and a second positioning step are provided on the inner annular surface of the outer annular enclosure, the center hole of the inner annular enclosure is a first threaded hole, and a center through hole is provided on the upper cover, and the first threaded hole and the center through hole together constitute a mounting hole; The inner ring surface of the first piezoelectric ring is bonded to the first annular boss, the first piezoelectric ring is placed on the first annular positioning step, the outer ring surface of the second piezoelectric ring is bonded to the second annular boss, the second piezoelectric ring is placed on the second annular positioning step, and the annular mass block is sleeved and bonded between the first piezoelectric ring and the second piezoelectric ring.

2. The double-ring shear acceleration sensor according to claim 1, characterized in that: The material of the first piezoelectric ring and the second piezoelectric ring is piezoelectric ceramic, and the piezoelectric material of the piezoelectric ceramic is one of lead zirconate titanate ceramic, bismuth layered structure ceramic, potassium sodium niobate and bismuth scandate-lead titanate.

3. The double-ring shear type acceleration sensor according to claim 1, characterized in that: The first piezoelectric ring and the second piezoelectric ring are both axially polarized and have the same polarization direction.

4. The double-ring shear acceleration sensor according to claim 1, characterized in that: The thickness and height of the first annular positioning step and the second annular positioning step are equal, and the thickness and height of the first annular boss and the second annular boss are equal.

5. The double-ring shear acceleration sensor according to claim 1, characterized in that: The cross-section of the annular mass block is T-shaped.

6. The double-ring shear type acceleration sensor according to claim 5, characterized in that: The annular mass block and the first piezoelectric ring are bonded together by high-temperature conductive adhesive, and the annular mass block and the second piezoelectric ring are bonded together by high-temperature conductive adhesive. The first piezoelectric ring and the second piezoelectric ring are polarized in the same direction along the axial direction.

7. The double-ring shear acceleration sensor according to claim 6, characterized in that: The inner ring surface of the first piezoelectric ring is bonded to the outer ring surface of the inner ring enclosure by using high-temperature conductive adhesive, and the outer ring surface of the second piezoelectric ring is bonded to the inner ring surface of the outer ring enclosure by using high-temperature conductive adhesive.

8. The double-ring shear type acceleration sensor according to claim 1, characterized in that: The top end of the outer annular enclosure is provided with a connecting internal thread and a step, the outer peripheral surface of the upper cover is provided with a connecting external thread, and the upper cover is connected to the base through the connecting external thread and the connecting internal thread.

9. A method for forming a double-ring shear-type acceleration sensor, characterized in that: The dual-annular shear-type accelerometer according to any one of claims 1 to 8 comprises a base, an annular mass, a first piezoelectric ring, a second piezoelectric ring, an upper cover, and a joint, wherein the base comprises a bottom plate, an outer annular plate, and an inner annular plate, wherein the bottom plate, the outer annular plate, and the inner annular plate together form an accommodating cavity, and the method comprises: Step 1: Based on the performance indicators required for the dual-annular shear-type piezoelectric accelerometer, preliminarily determine the process route, select the materials of the base, annular mass block, first piezoelectric ring, second piezoelectric ring, upper cover, and joint, repeatedly optimize the structural parameters based on the materials of the base, annular mass block, first piezoelectric ring, second piezoelectric ring, upper cover, and joint until the simulation results meet the expected performance indicators, and then design and prepare each component based on the structural parameters obtained by simulation; Step 2: Complete the axial polarization of the piezoelectric ring, then grind and remove the end surface electrodes, apply conductive silver glue on the outer ring surface of the first piezoelectric ring and the inner ring surface of the second piezoelectric ring, and embed the first piezoelectric ring and the second piezoelectric ring on the inner and outer ring surfaces of the annular mass block respectively and solidify them to obtain the sensor sensitive element; Step 3: Apply conductive silver glue on the inner ring surface of the first piezoelectric ring and the outer inner ring surface of the second piezoelectric ring, and insert the sensor sensitive element between the outer annular plate and the inner annular plate; Step 4: Glue the wire to the annular mass block with conductive silver glue, and screw the connector into the second threaded hole of the outer annular plate of the base; Step 5: Install the upper cover onto the base.

10. The forming method of the double-annular shear type acceleration sensor according to claim 9, characterized in that: Step 1 specifically includes: The simulation was performed using COMSOL Multiphysics software developed by the Swedish COMSOL Group; Step 2 specifically includes: The two end surfaces of the first piezoelectric ring and the second piezoelectric ring were evenly coated with conductive silver glue, and then placed in an oven for curing at a temperature of 100°C for 30 minutes; The first piezoelectric ring and the second piezoelectric ring are placed in a silicone oil bath, and a pair of positive and negative electrode rods connected to a high-voltage DC polarization power supply are introduced to the two end surface electrodes of the first piezoelectric ring and the second piezoelectric ring; The silicone oil bath was heated to 120°C using an electric heater. The polarization power supply voltage was then slowly increased until the required polarization electric field of 3 kV / mm was reached. The high voltage polarization was maintained for half an hour to complete the polarization of the first and second piezoelectric rings. After the polarization of the first piezoelectric ring and the second piezoelectric ring is completed, the end surface electrodes of the first piezoelectric ring and the second piezoelectric ring are removed, and high-temperature conductive silver glue is applied to the outer ring surface of the first piezoelectric ring and the inner ring surface of the second piezoelectric ring. The first piezoelectric ring and the second piezoelectric ring are placed on the inverted annular mass block until the end surface of the piezoelectric ring abuts against the step of the mass block. When placing them, ensure that the polarization direction of the first piezoelectric ring is the same as the polarization direction of the second piezoelectric ring. Finally, put them into an oven for curing at a curing temperature of 100° C. and a curing time of 30 minutes; Step three specifically includes: Apply high-temperature conductive silver glue to the inner ring surface of the first piezoelectric ring and the outer ring surface of the second piezoelectric ring, bond the inner ring surface of the first piezoelectric ring to the outer ring surface of the inner annular plate, and bond the outer ring surface of the second piezoelectric ring to the inner ring surface of the outer annular plate, ensuring that the end faces of the first and second piezoelectric rings abut against the end faces of the first and second positioning steps, and place them in an oven for curing at a temperature of 100° C. for 30 minutes; Step 4 specifically includes: Apply high-temperature resistant insulating glue on the inner wall of the central through hole of the connector and dry it; The first piezoelectric ring and the second piezoelectric ring are bonded to the annular mass block using high-temperature conductive adhesive and then put into an oven for curing; Bond the copper or silver wire to the mass block with high-temperature conductive adhesive, apply high-temperature insulating silicone around the wire, and solidify it; Screw the connector into the second threaded hole and lead the wire out of the connector; Step 5 specifically includes: Install the upper cover onto the base, bond the upper cover and the base with high-temperature conductive adhesive, and place them in an oven for curing at a temperature of 100°C for 30 minutes.

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