Quartz beam accelerometer

Abstract

The application relates to the technical field of accelerometers, and provides a quartz vibrating beam accelerometer. The quartz vibrating beam accelerometer comprises a swing assembly mechanism, the swing assembly mechanism comprises a rigid frame, a flexible beam and a mass swing which are sequentially connected, a vibrating beam mechanism, the rigid frame and the mass swing are fixed on the vibrating beam mechanism respectively, and a damping mechanism, the damping mechanism comprises a plurality of damping structures which are sequentially connected, and one end of the rigid frame is connected with the plurality of damping structures. The quartz vibrating beam accelerometer provided by the application is connected with the rigid frame through the damping mechanism, the external impact is mechanically isolated through the stress isolation mode, the external instantaneous impact force is gradually attenuated, the influence of external vibration or impact on the swing assembly mechanism is reduced to the minimum, the measurement error of the quartz vibrating beam accelerometer is reduced, and the measurement precision is improved.

Description

Technical Field

[0001] This invention relates to the field of accelerometer technology, and more particularly to a quartz vibrating beam accelerometer. Background Technology

[0002] The quartz beam accelerometer uses a mass pendulum sensing component to detect the acceleration of the carrier. The force-sensitive quartz beam converts the inertial force caused by acceleration into a frequency change and directly outputs a frequency proportional to the magnitude of the measured acceleration. The quartz beam accelerometer does not have the velocity increment error caused by analog-to-digital conversion, is compatible with high-speed digital inertial navigation systems, has a small temperature drift coefficient, and has advantages such as high accuracy, low cost, and small size.

[0003] A quartz vibrating beam accelerometer typically consists of a flexible beam, a sensitive mass, and a quartz resonator. The sensitive mass and the flexible beam form a pendulum assembly structure, which can be configured using either a single resonator or a push-pull resonator. The quartz resonator is bonded between the sensitive mass and the base. Under the inertial force generated by the input shaft acceleration, the sensitive mass exerts axial tension, compression, or torque on the quartz vibrating beam, causing a change in the resonant beam frequency. This frequency change reflects the magnitude and direction of the input acceleration.

[0004] Quartz accelerometer sensing structures can be divided into two types: split-type and integrated-type. However, existing quartz accelerometer sensing structures are directly bonded to the tube shell base, lacking stress isolation devices. When horizontal vibration is input, mechanical vibration is easily transmitted directly to the pendulum assembly through the shell, resulting in large overshoot of the flexible beam, causing large zero deviation at the mid-oscillation, or even causing the flexible beam to break. Summary of the Invention

[0005] This invention provides a quartz vibrating beam accelerometer to solve the problem that in the prior art, the sensitive structure of the quartz accelerometer is directly bonded to the tube base, which easily leads to a large zero deviation at the mid-oscillation or even the fracture of the flexible beam when vibration is input in the horizontal direction. This invention adopts a stress isolation device to attenuate the instantaneous impact force of the external environment step by step, so as to minimize the impact of external vibration or impact on the pendulum assembly.

[0006] This invention provides a quartz vibrating beam accelerometer, comprising:

[0007] A pendulum assembly mechanism; the pendulum assembly mechanism includes a rigid frame, a flexible beam, and a mass pendulum connected in sequence;

[0008] A vibrating beam mechanism, wherein the rigid frame and the mass pendulum are respectively fixed on the vibrating beam mechanism;

[0009] A vibration damping mechanism, comprising a multi-stage vibration damping structure connected in sequence, wherein one end of the rigid frame is connected to the multi-stage vibration damping structure.

[0010] According to the quartz vibrating beam accelerometer provided in this application, the multi-stage vibration reduction structure includes:

[0011] Internal vibration damping components;

[0012] An external vibration damping component is provided, and the internal vibration damping component is disposed inside the external vibration damping component. The external vibration damping component is connected to one end of the rigid frame through the internal vibration damping component.

[0013] According to a quartz vibrating beam accelerometer provided in this application, the external vibration damping assembly includes: an external vibration damping frame and an external vibration isolation beam;

[0014] The internal vibration damping component includes:

[0015] An inner vibration damping frame is disposed inside the outer vibration damping frame, and the pendulum assembly is disposed inside the inner vibration damping frame. The inner vibration damping frame is connected to the outer vibration damping frame through the outer vibration damping beam.

[0016] An inner vibration isolation beam is provided, and the inner vibration damping frame is connected to the rigid frame through the inner vibration isolation beam.

[0017] According to the quartz vibrating beam accelerometer provided in this application, the inner vibration isolation beam is disposed on the side of the inner vibration damping frame close to the rigid frame; the outer vibration isolation beam is disposed on the side of the inner vibration damping frame away from the inner vibration isolation beam.

[0018] According to the quartz vibrating beam accelerometer provided in this application, it also includes:

[0019] Upper damping plate;

[0020] Lower damping plate;

[0021] Microspheres are used to bond the upper damping plate to the inner damping frame, and the lower damping plate is also bonded to the inner damping frame via microspheres.

[0022] According to the quartz vibrating beam accelerometer provided in this application, the vibrating beam mechanism includes:

[0023] Tuning fork vibrator;

[0024] The lever assembly is used to fix the tuning fork beam to the rigid frame and the mass pendulum, respectively.

[0025] According to the quartz vibrating beam accelerometer provided in this application, the lever assembly includes:

[0026] Multiple folded beams are connected to form a frame structure. The first end of each folded beam is connected to the tuning fork vibrating beam, the second end of each folded beam is connected to the mass pendulum, and the third end of each folded beam is connected to the rigid frame.

[0027] According to the quartz vibrating beam accelerometer provided in this application, it further includes a tuning fork stress isolation beam, wherein the tuning fork vibrating beam is composed of two single beams coupled together through a tuning fork node, and the tuning fork node is connected to the first end of the folded beam through the tuning fork stress isolation beam.

[0028] According to the quartz vibrating beam accelerometer provided in this application, the vibrating beam mechanism located above the rigid frame and the mass pendulum includes:

[0029] A temperature-sensing tuning fork, the temperature-sensing tuning fork being connected to the side of the folding beam near the rigid frame;

[0030] The first counterweight tuning fork is connected to the side of the folding beam near the rigid frame and is symmetrically arranged with the temperature measuring tuning fork.

[0031] The vibrating beam mechanism located below the rigid frame and the mass pendulum includes:

[0032] At least two second counterweight tuning forks are connected to the side of the folding beam near the rigid frame, and the second counterweight tuning forks are symmetrically arranged.

[0033] According to the quartz vibrating beam accelerometer provided in this application, at least one of the flexible beam, the mass block, and the temperature-measuring tuning fork is made of quartz material.

[0034] The present invention provides a quartz vibrating beam accelerometer, which is connected to a rigid frame through a vibration damping mechanism. Through stress isolation, it mechanically isolates external input impacts, gradually attenuates the instantaneous impact force, minimizes the impact of external vibrations or impacts on the pendulum assembly mechanism, reduces the measurement error of the quartz vibrating beam accelerometer, and improves the measurement accuracy. Attached Figure Description

[0035] To more clearly illustrate the technical solutions in this invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0036] Figure 1 This is a cross-sectional schematic diagram of the quartz vibrating beam accelerometer provided by the present invention;

[0037] Figure 2 This is a top view of the quartz vibrating beam accelerometer (with the upper damping plate removed) provided by the present invention;

[0038] Figure 3 This is a bottom view schematic diagram of the quartz vibrating beam accelerometer provided by the present invention;

[0039] Figure 4 This is a schematic diagram of the vibrating beam mechanism provided by the present invention;

[0040] Figure 5 This is a top view schematic diagram of the upper damping plate provided by the present invention;

[0041] Figure 6 This is a front view schematic diagram of the upper damping plate provided by the present invention;

[0042] Figure 7 This is a top view (without shading) of the pendulum assembly mechanism and vibration damping mechanism provided by the present invention.

[0043] Figure label:

[0044] 1: Rigid frame; 2: Flexible beam; 3: Mass pendulum; 4: Outer damping frame; 5: Outer vibration isolation beam; 6: Inner damping frame; 7: Inner vibration isolation beam; 8: Upper damping plate; 9: Lower damping plate; 10: Microsphere; 11: Tuning fork vibrating beam; 12: Folded beam; 13: Tuning fork node; 14: Tuning fork stress isolation beam; 15: Folded beam node; 16: Anchor area; 17: Temperature-measuring tuning fork; 18: First counterweight tuning fork; 19: Second counterweight tuning fork; 20: Silicone patch. Detailed Implementation

[0045] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0046] The following is combined Figures 1-7 (To clearly illustrate its internal structure) Figure 2 and Figure 3 The cross-sectional view in the image has had some of the shading lines removed. Figure 7 All shading lines were removed, and Figure 1 To clearly illustrate its structure, shaded lines are retained in the text. This invention describes a quartz vibrating beam accelerometer. The quartz vibrating beam accelerometer includes: a pendulum assembly mechanism, a vibrating beam mechanism, and a vibration damping mechanism, etc.

[0047] The pendulum assembly includes a rigid frame 1, a flexible beam 2, and a mass pendulum 3 connected in sequence; the rigid frame 1 and the mass pendulum 3 are respectively fixed on the vibrating beam mechanism; the vibration damping mechanism includes a multi-stage vibration damping structure connected in sequence, with one end of the rigid frame 1 connected to the multi-stage vibration damping structure.

[0048] Specifically, in this embodiment, the connection between the vibration damping mechanism and the rigid frame 1 achieves mechanical isolation from horizontal external impacts. In existing technologies, the sensitive structure is directly bonded to the shell base. When horizontal vibrations occur, the mechanical vibration is directly transmitted to the mass pendulum 3 through the shell, causing significant overshoot of the flexible beam 2, leading to large zero-bias during vibration and even breakage of the flexible beam 2. In this embodiment, the vibration damping mechanism is essentially a stress isolation method, gradually attenuating the instantaneous impact force and minimizing the influence of external vibrations or impacts on the pendulum assembly mechanism.

[0049] The present invention provides a quartz vibrating beam accelerometer, which is connected to a rigid frame 1 through a vibration damping mechanism. Through stress isolation, it mechanically isolates external input impacts, gradually attenuates the instantaneous impact force, minimizes the impact of external vibrations or impacts on the pendulum assembly mechanism, reduces the measurement error of the quartz vibrating beam accelerometer, and improves the measurement accuracy.

[0050] In one embodiment of the present invention, the multi-stage vibration damping structure includes an inner vibration damping component and an outer vibration damping component. The inner vibration damping component is disposed inside the outer vibration damping component, and the outer vibration damping component is connected to one end of the rigid frame 1 through the inner vibration damping component. In this embodiment, the multi-stage vibration damping structure employs a combination of inner and outer double-layer vibration damping components, thereby achieving a gradual attenuation of instantaneous external impact forces and improving the vibration damping effect. It should be understood that three-stage, four-stage, or even multi-stage vibration damping structures can also be used, with nested connection designs tailored to actual application needs.

[0051] In one embodiment of the present invention, the external vibration damping assembly includes an external vibration damping frame 4 and an external vibration isolation beam 5; the internal vibration damping assembly includes an internal vibration damping frame 6 and an internal vibration isolation beam 7. The internal vibration damping frame 6 is disposed inside the external vibration damping frame 4, the pendulum assembly is disposed inside the internal vibration damping frame 6, and the internal vibration damping frame 6 is connected to the external vibration damping frame 4 via the external vibration damping beam; the internal vibration damping frame 6 is connected to the rigid frame 1 via the internal vibration isolation beam 7. In this embodiment, two-stage vibration damping is achieved through the internal vibration damping frame 6 and the external vibration damping frame 4, and vibration isolation between the internal vibration damping frame 6 and the external vibration damping frame 4 is achieved using the external vibration isolation beam 5, while vibration isolation between the internal vibration damping frame 6 and the rigid frame 1 is achieved using the internal vibration isolation beam 7.

[0052] In one embodiment of the present invention, the inner vibration isolation beam 7 is disposed on the side of the inner vibration damping frame 6 closer to the rigid frame 1; the outer vibration isolation beam 5 is disposed on the side of the inner vibration damping frame 6 away from the inner vibration isolation beam 7. In this embodiment, the inner vibration isolation beam 7 and the outer vibration isolation beam 5 are respectively disposed on the left and right sides, which can further balance the vibration isolation and thus improve the vibration isolation effect.

[0053] In one embodiment of the invention, to further relieve stress, such as Figure 3As shown, the outer vibration damping frame 4 is bonded to the tube shell substrate with elastic silicone. To prevent over-positioning, three-point positioning is adopted. The bonding area of ​​the elastic silicone patch 20 is an elliptical bonding scheme. The viscosity of the silicone is 80-120 Pa·s, the shear strength is 5.9 MPa, and it is cured at room temperature for 12 hours. The thickness of the elastic silicone patch 20 is 400-500 μm.

[0054] In one embodiment of the present invention, the quartz vibrating beam accelerometer further includes an upper damping plate 8, a lower damping plate 9, and microspheres 10. The upper damping plate 8 is bonded to the inner damping frame 6 via microspheres 10, and the lower damping plate 9 is bonded to the inner damping frame 6 via microspheres 10. In this embodiment, an adjustable gap cantilever damping plate bonding scheme is adopted. Specifically, an epoxy adhesive with a coefficient of thermal expansion matching that of quartz crystal is selected as the adhesive for the upper damping plate 8 and the lower damping plate 9. Microspheres 10 with a controllable diameter are added to the epoxy adhesive. The microspheres 10 can be micro-quartz balls. The micro-quartz balls and epoxy adhesive are uniformly stirred and fully fused. This epoxy adhesive is used to achieve single-sided bonding between the damping plate and the rigid frame 1 in the pendulum assembly mechanism, forming a cantilever damping plate structure. By using micro-quartz spheres of different diameters, precise control of the air film gap between the mass pendulum 3 and the cantilever damping plate can be achieved. Controlling this gap improves the dynamic characteristics of the mass pendulum 3, while the cantilever damping plate also functions as a limiting stop. The thickness of the "air film" is controlled by the diameter of the micro-quartz spheres, with epoxy resin acting as an adhesive to firmly connect the damping plate, microspheres, and pendulum assembly. Specifically, the "air film" is the gas-filled gap between the mass pendulum 3 and the damping plate. This gap is used to adjust the dynamic characteristics of the sensitive structure, and its thickness is generally around 10µm to 50µm. Utilizing the inherent flexibility and pressure-film damping effect of the damping plate, soft contact (commonly known as "soft landing") of the mass pendulum 3 is achieved under large impact conditions. First, gas pressure-film damping reduces some of the overshoot of the mass pendulum 3. When the mass pendulum 3 makes hard contact with the damping plate, the outward bending deformation of the damping plate absorbs some of the overshoot, effectively protecting the flexible beam 2 structure.

[0055] In one embodiment of the present invention, the vibrating beam mechanism includes a tuning fork vibrating beam 11 and a lever assembly. The tuning fork vibrating beam 11 is fixedly connected to the rigid frame 1 and the mass pendulum 3 via the lever assembly. In this embodiment, the lever assembly is used to amplify the axial force of the vibrating beam, increasing the force-frequency coefficient of the tuning fork vibrating beam 11 assembly, thereby improving the overall sensitivity of the sensitive structure.

[0056] In one embodiment of the present invention, the lever assembly includes: multiple folded beams 12, which are connected to form a frame structure (in this embodiment, the folded beams 12 form a rhomboid structure, and the lever assembly adopts the lever principle of a rhomboid ring), the first end of the folded beam 12 is connected to the tuning fork vibrating beam 11, the second end of the folded beam 12 is connected to the mass pendulum 3, and the third end of the folded beam 12 is connected to the rigid frame 1. Specifically, as... Figure 4 As shown, this embodiment uses a folded beam 12 structure to amplify the axial force of the vibrating beam. The amplification principle is as follows: when the pendulum assembly senses acceleration and undergoes displacement, the deformation borne by the vibrating beam is converted from tensile / compressive deformation to bending deformation through the folded beam 12. Typically, the bending stiffness of the rod material is much smaller than its tensile / compressive stiffness. Under the same acceleration input, the vibrating beam mechanism with lever assembly experiences greater axial stress, thereby increasing the force-frequency coefficient of the vibrating beam mechanism and thus improving the sensitivity of the sensitive structure. Specifically, four folded beams 12 form a rhomboid structure, which is connected to the tuning fork vibrating beam 11 through folded beam nodes 15 to form a composite beam structure. This composite beam structure is an integral structure and is fixedly connected to the mass pendulum 3 and the rigid frame 1 through the folded beams 12. When the mass pendulum 3 senses the acceleration input on the sensitive axis, the relative position between the upper and lower anchor areas 16 of the vibrating beam mechanism changes, which will cause tensile and compressive deformation of the folding beam 12. When the relative position of the two anchor areas 16 increases, the axial compressive stress of the tuning fork vibrating beam 11 will be multiplied through the four folding beams 12, causing the tuning fork resonant frequency to decrease; when the relative position of the two anchor areas 16 decreases, the axial tensile stress of the tuning fork vibrating beam 11 will be multiplied through the four folding beams 12, causing the tuning fork resonant frequency to increase.

[0057] In one embodiment of the present invention, the quartz vibrating beam accelerometer further includes a tuning fork stress isolation beam 14. The tuning fork vibrating beam 11 consists of two single beams coupled together via a tuning fork joint 13. The tuning fork joint 13 is connected to the first end of the folded beam 12 via the tuning fork stress isolation beam 14. In this embodiment, the tuning fork stress isolation beam 14 is used to connect the tuning fork vibrating beam 11 and the folded beam 12, which can effectively isolate the influence of external thermal stress on the tuning fork vibrating beam 11, solve the stress isolation problem under high sensitivity conditions, and thus improve measurement accuracy. Specifically, the folded beam 12 is connected to one end of the tuning fork stress isolation beam 14 via a folded beam joint 15, and the other end of the tuning fork stress isolation beam 14 is connected to the tuning fork joint 13.

[0058] In one embodiment of the present invention, the vibrating beam mechanism located above the rigid frame 1 and the mass pendulum 3 includes: a pair of temperature-measuring tuning forks 17 and a first counterweight tuning fork 18; the vibrating beam mechanism located below the rigid frame 1 and the mass pendulum 3 includes: at least two second counterweight tuning forks 19. The temperature-measuring tuning fork 17 is connected to the side of the folding beam 12 near the rigid frame 1; the first counterweight tuning fork 18 is connected to the side of the folding beam 12 near the rigid frame 1 and is symmetrically arranged with the temperature-measuring tuning fork 17; the second counterweight tuning forks 19 are connected to the side of the folding beam 12 near the rigid frame 1 and are symmetrically arranged. In this embodiment, the vibrating beam mechanism located below the rigid frame 1 and the mass pendulum 3 is hereinafter referred to as the lower vibrating beam; the vibrating beam mechanism located above the rigid frame 1 and the mass pendulum 3 is hereinafter referred to as the upper vibrating beam. Figure 4 Taking the upper vibrating beam structure as an example, the lower vibrating beam structure is... Figure 4 Based on the existing structure, the temperature-sensing tuning fork 17 is replaced with a second counterweight tuning fork 19. Integrating the temperature-sensing tuning fork 17 into the tuning fork vibrating beam 11 allows for accurate reflection of the core temperature of the vibrating beam, improving temperature compensation and avoiding errors introduced by the secondary bonding of the temperature sensing unit. The integrated temperature-sensing tuning fork 17 adopts a single-end fixed tuning fork shape. The two fork teeth use planar differential mode as the working mode, with a recommended resonant frequency of 120kHz~130kHz. The temperature model of the temperature-sensing tuning fork 17 in planar differential mode is as follows:

[0059]

[0060] In the above formula, Δf = f - f0; ΔT = T - T0; f and f0 are the resonant frequencies of the thermometric tuning fork 17 at temperatures T and T0 (T0 = 25℃), respectively; α0, α1, α2, and α3 are the 0th to 3rd order temperature coefficients, respectively. The thermometric tuning fork 17 uses a double-rotated Y-cut quartz crystal, making α2 and α3 approach zero, with a first-order temperature coefficient of 35–45 ppm / ℃, a temperature measurement range of -80℃ to 230℃, and a temperature measurement accuracy of 0.02℃. To improve the symmetry of the sensitive structure, a counterweight tuning fork is added. The counterweight tuning fork has the same structural dimensions as the thermometric tuning fork 17. Therefore, the upper vibrating beam has one symmetrically arranged thermometric tuning fork 17 and one first counterweight tuning fork 18, and the lower vibrating beam has two symmetrically arranged second counterweight tuning forks 19.

[0061] Furthermore, the vibrating beam mechanism in this invention is an integrated design, that is, the tuning fork vibrating beam 11, the tuning fork stress isolation beam 14, the folding beam 12, the temperature measuring tuning fork 17, and the counterweight tuning fork are integrated into one structure.

[0062] In one embodiment of the present invention, at least one of the flexible beam 2, the mass block, and the temperature-measuring tuning fork 17 is made of quartz material. Preferably, the flexible beam 2, the mass block, the upper vibrating beam, the lower vibrating beam, the upper damping plate 8, the lower damping plate 9, and the temperature-measuring tuning fork 17 are all made of quartz crystal material, which improves the matching of the thermal expansion coefficients of the materials and solves the temperature drift problem caused by the mismatch of the thermal expansion coefficients of the materials.

[0063] This invention proposes a specific embodiment of a quartz vibrating beam accelerometer. It employs an adjustable-damping all-quartz differential vibrating beam structure, such as... Figure 1 As shown, the entire sensitive structure consists of upper and lower vibrating beams with a temperature-measuring tuning fork 17 and a lever assembly, a quartz flexible pendulum with stress isolation, and upper and lower cantilever damping plates. The two nodes of the upper and lower vibrating beams are rigidly connected to the mass pendulum 3 and the rigid frame 1 respectively via a low-temperature glass slurry sintering process. The bonding gap is controlled between 50µm and 100µm. The viscosity of the glass slurry is 80–100 Pa·s, the adhesive removal temperature is 120℃, the pre-sintering temperature is 220–240℃, the sintering temperature is 330–360℃, and the coefficient of thermal expansion is 10–13 ppm / ℃, ensuring a compatible seal. The rigid connection between the damping plate and the inner damping frame 6 is achieved through an epoxy adhesive bonding process with quartz balls. The gap between the damping plate and the mass pendulum 3 is controlled between 20µm and 200µm.

[0064] A top view of the quartz vibrating beam sensitive structure without the upper damping plate 8, as shown below. Figure 2 As shown, the bonding area between the damping plate and the inner damping frame 6 is rectangular. The adhesive is an epoxy resin with quartz balls, with a viscosity of 80–100 Pa·s. The diameter of the quartz balls can be selected from 20 μm to 200 μm, with a processing diameter tolerance of ±5 μm. The curing temperature is 120–150℃, the curing time is 30–60 min, and the coefficient of thermal expansion is 10–13 ppm / ℃, ensuring a compatible seal. The damping plate is bonded on one side, forming a cantilever beam with a flexible structure. The recommended flexible resonant frequency of the damping plate is 4.5 kHz to 5.5 kHz.

[0065] A bottom view of a quartz vibrating beam sensitive structure, such as... Figure 3 As shown, in order to release stress, the outer vibration damping frame 4 is bonded to the tube shell base with elastic silicone. To prevent over-positioning, an elliptical area at three points is used as the bonding scheme. The silicone has a viscosity of 80-120 Pa·s, a shear strength of 5.9 MPa, and is cured at room temperature for 12 hours. The thickness of the elastic silicone patch 20 is 400-500 μm.

[0066] Upper and lower vibrating beams with a temperature-measuring tuning fork 17 and a lever assembly, such as Figure 4As shown, it includes eight parts: tuning fork vibrating beam 11, tuning fork joint 13, tuning fork stress isolation beam 14, folded beam joint 15, folded beam 12, anchor area 16, temperature-sensing tuning fork 17, and counterweight tuning fork. Each pair of tuning fork vibrating beams 11 operates through horizontal differential mode resonance of two single beams. The two single beams are coupled together through tuning fork joint 13. Tuning fork joint 13 connects to a single tuning fork stress isolation beam 14 to achieve stress isolation. The four folded beams 12 and tuning fork vibrating beams 11 form a rhombic composite beam structure in the joint area. The other two ends of the folded beams 12 are fixed to the mass pendulum 3 and the rigid frame 1, respectively. When the mass pendulum 3 senses acceleration input on the sensitive axis, the relative position between the two anchor areas 16 changes, which will cause tensile and compressive deformation of the folded beams 12. When the phase position of the two anchor areas 16 increases, the axial compressive stress of the tuning fork vibrating beams 11 will be multiplied through the four folded beams 12, causing the tuning fork resonant frequency to decrease. When the relative positions of the two anchor zones 16 decrease, the axial tensile stress of the tuning fork vibrating beam 11 will be multiplied through the four folded beams 12, causing the resonant frequency of the tuning fork to increase. To prevent frequency lock-up in the upper and lower vibrating beams, different structural parameters are required for the upper and lower vibrating beams. The recommended resonant frequency for the upper vibrating beam is 34kHz to 36kHz, and the recommended quality factor Q is 8000 to 10000; the recommended resonant frequency for the lower vibrating beam is 30kHz to 32kHz, and the recommended quality factor Q is 8000 to 10000. This vibrating beam is an axisymmetric structure, symmetrical along both the x-axis and y-axis.

[0067] The integrated temperature-sensing tuning fork 17 adopts a single-end fixed tuning fork structure. The two fork teeth use planar differential mode as the working mode, with a recommended resonant frequency of 120kHz to 130kHz. The temperature model of the temperature-sensing tuning fork 17 under planar differential mode is as follows:

[0068]

[0069] In the above formula, Δf = f - f0; ΔT = T - T0; f and f0 are the resonant frequencies of the thermometric tuning fork 17 at temperatures T and T0 (T0 = 25℃), respectively; α0, α1, α2, and α3 are the 0th to 3rd order temperature coefficients, respectively. The thermometric tuning fork 17 uses a double-rotated Y-cut quartz crystal, which makes α2 and α3 approach zero, the first-order temperature coefficient is 35-45 ppm / ℃, the temperature measurement range is -80℃ to 230℃, and the temperature measurement accuracy can reach 0.02℃.

[0070] To improve the symmetry of the sensitive structure, a counterweight tuning fork was added. The counterweight tuning fork and the temperature-sensing tuning fork 17 have the same structural dimensions. Therefore, the upper vibrating beam has one temperature-sensing tuning fork 17 and one counterweight tuning fork, and the lower vibrating beam has two counterweight tuning forks. The thickness of the temperature-sensing tuning fork 17, the counterweight tuning fork, the folded beam 12, the upper vibrating beam, and the lower vibrating beam is 80 μm. The folded beam 12 makes an angle θ0 = 60 degrees with the horizontal direction.

[0071] The cross-section of the quartz pendulum assembly and vibration damping mechanism, such as... Figure 1 As shown, it comprises seven parts: an outer damping frame 4, an outer damping beam, an inner damping frame 6, an inner damping beam, a rigid frame 1, a flexible beam 2, and a quartz mass pendulum 3. The entire pendulum assembly adopts an integrated manufacturing scheme. The flexible beam 2 and the quartz mass pendulum 3 achieve vibration damping and isolation through the inner and outer damping beams, preventing the impact of horizontal vibrations and impacts on the sensitive pendulum assembly. The top view of the structure is as follows. Figure 7 As shown, the recommended natural frequency of the flexible beam 2 is 2.5kHz to 3.5kHz. The upper and lower damping plates 9 are as follows... Figure 5 and Figure 6 As shown, it adopts a cuboid structure.

[0072] In summary, the quartz vibrating beam accelerometer provided by this invention has the following beneficial effects:

[0073] (1) The tuning fork vibrating beam 11 and the temperature measuring tuning fork 17 are integrated into a design with good process consistency. The temperature measuring unit is closer to the core temperature of the sensitive structure. The design of the counterweight tuning fork improves the symmetry of the sensitive structure, thereby suppressing the mechanical common mode error. The upper and lower differential tuning fork vibrating beams 11 are adopted, and the temperature common mode error of the tuning fork vibrating beam 11 is effectively suppressed.

[0074] (2) The adjustable gap cantilever damping plate design, through an epoxy adhesive bonding process with quartz balls, enables the air film gap between the damping plate and the mass pendulum 3 to be controllable and adjustable, improves the dynamic performance of the pendulum assembly, and utilizes the cantilever damping plate to absorb the impact energy in the sensitive axis direction, so as to achieve the "soft landing" of the mass pendulum 3 and prevent the flexible beam 2 from being damaged by overshoot.

[0075] (3) The tuning fork vibrating beam 11 structure with folded beam 12 is adopted. Through the multiplication effect of the lever assembly, the force frequency coefficient of the tuning fork vibrating beam 11 is improved. At the same time, the axial tensile stress borne by the vibrating beam is changed from the direction of the swing axis to the direction of the output axis, and the influence of the vibrating beam on the stiffness of the input shaft of the flexible beam 2 is improved.

[0076] (4) The design incorporates an internal and external two-stage vibration damping structure and silicone pads 20 to effectively suppress the impact of horizontal vibrations and shocks on the performance of the pendulum assembly, while also providing temperature and thermal stress isolation.

[0077] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A quartz tuning fork accelerometer, characterized by, include: A pendulum assembly mechanism; the pendulum assembly mechanism includes a rigid frame, a flexible beam, and a mass pendulum connected in sequence; A vibrating beam mechanism, wherein the rigid frame and the mass pendulum are respectively fixed on the vibrating beam mechanism; A vibration damping mechanism, comprising a multi-stage vibration damping structure connected in sequence, wherein one end of the rigid frame is connected to the multi-stage vibration damping structure; The multi-stage vibration reduction structure includes: Internal vibration damping components; An external vibration damping component is provided, and the internal vibration damping component is disposed inside the external vibration damping component. The external vibration damping component is connected to one end of the rigid frame through the internal vibration damping component. The external vibration damping assembly includes: an external vibration damping frame and an external vibration isolation beam; The internal vibration damping component includes: An inner vibration damping frame is disposed inside the outer vibration damping frame, and the pendulum assembly is disposed inside the inner vibration damping frame. The inner vibration damping frame is connected to the outer vibration damping frame through the outer vibration isolation beam. An inner vibration isolation beam is provided, and the inner vibration damping frame is connected to the rigid frame via the inner vibration isolation beam. The inner vibration isolation beam is located on the side of the inner vibration damping frame closer to the rigid frame; the outer vibration isolation beam is located on the side of the inner vibration damping frame away from the inner vibration isolation beam. Also includes: Upper damping plate; Lower damping plate; Microspheres are used to bond the upper damping plate to the inner damping frame, and the lower damping plate is also bonded to the inner damping frame via microspheres. The vibrating beam mechanism includes: Tuning fork vibrator; The lever assembly is used to fix the tuning fork beam to the rigid frame and the mass pendulum, respectively. The lever assembly includes: Multiple folded beams are connected to form a frame structure. The first end of each folded beam is connected to the tuning fork vibrating beam, the second end of each folded beam is connected to the mass pendulum, and the third end of each folded beam is connected to the rigid frame.

2. The quartz tuning fork accelerometer according to claim 1, characterized by It also includes a tuning fork stress isolation beam, wherein the tuning fork vibrating beam is composed of two single beams coupled together through a tuning fork node, and the tuning fork node is connected to the first end of the folded beam through the tuning fork stress isolation beam.

3. The quartz vibrating beam accelerometer according to claim 1, characterized in that, The vibrating beam mechanism located above the rigid frame and the mass pendulum includes: A temperature-sensing tuning fork, the temperature-sensing tuning fork being connected to the side of the folding beam near the rigid frame; The first counterweight tuning fork is connected to the side of the folding beam near the rigid frame and is symmetrically arranged with the temperature measuring tuning fork. The vibrating beam mechanism located below the rigid frame and the mass pendulum includes: At least two second counterweight tuning forks are connected to the side of the folding beam near the rigid frame, and the second counterweight tuning forks are symmetrically arranged.

4. The quartz vibrating beam accelerometer according to claim 3, characterized in that, At least one of the flexible beam, the mass pendulum, and the thermometric tuning fork is made of quartz.

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