Pendulum-type all-quartz resonant accelerometer with double flexible supports and assembly method of pendulum-type all-quartz resonant accelerometer

Abstract

The invention relates to a double-flexible-support pendulum type all-quartz resonant accelerometer and an assembly method thereof, the accelerometer comprises a sensitive mass block structure composed of a mass block, mass block flexible supports and stress isolation areas, an upper resonant beam is connected above the mass block, and a lower resonant beam is connected below the mass block; a lower limiting plate is connected below the sensitive mass block structure, and the lower part of the lower limiting plate is connected to the mounting base; an upper limiting plate and a lower limiting plate are connected above the sensitive mass block structure, and the sensitive mass block structure and the upper limiting plate penetrate through the positioning binding post; the outer sides of the lower limiting plate, the sensitive mass block structure and the upper limiting plate are provided with a shell, and the shell is connected to the mounting base; the upper resonant beam and the lower resonant beam are electrically connected with a resonant circuit in the mounting base through positioning binding posts, and signals are transmitted to the resonant circuit; according to the invention, the environmental adaptability of the accelerometer is improved, the temperature characteristic of the accelerometer is reduced, the volume of the accelerometer is reduced, and the accelerometer adapts to the miniaturization and high-precision development trend of an inertial navigation system.

Description

Technical Field

[0001] The invention relates to the technical field of accelerometers, and in particular to a double-flexure-supported pendulum-type all-quartz resonant accelerometer and an assembly method thereof. Background Art

[0002] Inertial navigation is the basis of precision strikes. Accelerometers are one of the core instruments of inertial navigation. Their accuracy level determines the strike capability of weapons and equipment. With the development of technology, weapon models have higher and higher requirements for the size, accuracy, and reliability of accelerometers. There is a gap between the existing accelerometers and future equipment needs. Quartz resonant accelerometers have the characteristics of small size, high precision potential, digital output, and strong environmental adaptability. They are considered by the industry to be the representative product of the next generation of high-precision accelerometers. Due to the direct digital output of quartz resonant accelerometers, the accuracy error caused by analog-to-digital conversion is effectively reduced. At the same time, it saves the volume space of the analog-to-digital conversion board for the inertial navigation system, adapting to the development trend of miniaturization of inertial navigation systems. Quartz resonant accelerometers have become a hot topic for research in scientific research institutes of various countries.

[0003] The structural principle of the existing quartz resonant accelerometer (Zhang Liyuan, Quartz Vibrating Beam Accelerometer System Based on Double Beam Structure [D], Southeast University, 2016) is that the resonant beam is attached to a mass block supported by a single flexible hinge, and the resonant beam and the mass block are assembled by welding. The welding of the resonant beam and the mass block produces a large assembly stress, which affects the bias stability of the accelerometer; the mass block is designed with a single flexible support, and its mechanical resistance is poor under the action of a large mechanical environment; the resonant beam and the mass block are made of heterogeneous materials with different linear expansion coefficients, resulting in a certain gap between the temperature characteristics of the accelerometer and the model application.

[0004] As the core instrument of the inertial navigation acceleration channel, the quartz resonant accelerometer has a theoretical accuracy of 1.0E-07. With the improvement of quartz material performance and MEMS process level, the accuracy and reliability of the quartz resonant accelerometer will reach a higher level. The quartz resonant accelerometer will have broad application prospects in the fields of aviation, aerospace, navigation, weapons, etc. However, the above-mentioned existing technologies still have the following disadvantages: 1) There is still a certain gap between the environmental adaptability of the existing quartz resonant accelerometer and the actual application, which needs to be further improved; 2) The temperature characteristics (including temperature coefficient and temperature hysteresis) of the existing quartz resonant accelerometer are relatively high, which is a key factor limiting its application; 3) The volume of the existing quartz resonant accelerometer is still relatively large, which is not suitable for the miniaturization and high-precision development trend of the inertial navigation system. Summary of the invention

[0005] In order to overcome the shortcomings of the above-mentioned prior art, the purpose of the present invention is to provide a double flexible support pendulum-type all-quartz resonant accelerometer and an assembly method thereof, which improves the environmental adaptability of the accelerometer, reduces the temperature characteristics of the accelerometer, reduces the size of the accelerometer, and adapts to the miniaturization and high-precision development trend of inertial navigation systems.

[0006] In order to achieve the above purpose, the present invention adopts the following technical solutions:

[0007] A double flexible support pendulum all-quartz resonant accelerometer, comprising a sensitive mass block structure consisting of a mass block 3, a mass block flexible support 4, and a stress isolation zone 5, wherein an upper resonant beam 6 is connected above the mass block 3, and a lower resonant beam 7 is connected below the mass block 3;

[0008] A lower limit plate 2 is connected below the sensitive mass block structure, and the lower limit plate 2 is connected to the mounting base 1; an upper limit plate 8 is connected above the sensitive mass block structure, and the lower limit plate 2, the sensitive mass block structure, and the upper limit plate 8 penetrate the positioning terminal 9; a shell 10 is provided outside the lower limit plate 2, the sensitive mass block structure, and the upper limit plate 8, and the shell 10 is connected to the mounting base 1;

[0009] The upper resonant beam 6 and the lower resonant beam 7 are electrically connected to the resonant circuit in the mounting base 1 via the positioning terminal 9, and transmit the signal to the resonant circuit.

[0010] The sensitive mass block structural material is made of far-ultraviolet quartz glass, including a mass block 3, which is sensitive to external input acceleration and provides a mounting frame for an upper resonant beam 6 and a lower resonant beam 7. An upper resonant beam mounting groove 16 is provided above the fixed end of the mass block 3, and a lower resonant beam mounting groove 17 is provided below the fixed end. A lower resonant beam signal electrode lead-out layer 18 is symmetrically provided on the left and right above the fixed end of the mass block 3. Mass block flexible supports 4 are connected to both sides of the fixed end of the mass block 3. The mass block flexible support 4 is connected to the mass block swing tongue 21, and a stress isolation zone 5 is provided between the mass block swing tongue 21 and the mass block flexible support 4. A plurality of mounting bosses 20 for mounting an upper limit plate 8 and a lower limit plate 2 are respectively provided on the upper and lower surfaces of an outer mounting frame 22 around the mass block 3; a resonant beam vibration limit plate 19 is provided on the outer side of the upper resonant beam 6 and the lower resonant beam 7.

[0011] The mounting base 1 is made of stainless steel, the resonant circuit is embedded in the mounting base 1 , and a plurality of positioning terminals 9 are sintered on the mounting base 1 .

[0012] The upper limit plate 8 and the lower limit plate 2 have the same structure and are made of far ultraviolet quartz glass. The left and right half surfaces inside the upper limit plate 8 each have a positioning terminal sintering hole 14 and the outer side is provided with a plurality of boss mounting holes 15.

[0013] The upper resonant beam 6 and the lower resonant beam 7 are based on the piezoelectric effect. When an external accelerometer is input, the mass block 3 converts the external input accelerometer into an applied force. The upper resonant beam 6 and the lower resonant beam 7 are sensitive to the change in the applied force and convert the change in force into a change in frequency. The frequency of the upper resonant beam 6 and the lower resonant beam 7 increases and decreases, and the frequency difference between the two resonant beams is linearly related to the input acceleration, thereby realizing acceleration measurement.

[0014] The housing 10 is connected to the mounting base 1 by means of sealing adhesive or laser welding to achieve sealing of the accelerometer.

[0015] The positioning terminal 9 realizes the precise positioning of the upper limit plate 8 and the lower limit plate 2 and the lead-out of the signals of the upper resonance beam 6 and the lower resonance beam 7 through the positioning terminal through holes 14 of the upper limit plate 8 and the lower limit plate 2. The material is stainless steel with silver-plated outer surface.

[0016] A method for assembling a double-flexure-supported pendulum-type all-quartz resonant accelerometer comprises the following steps:

[0017] 1) The mounting base 1 is placed on the positioning tool, and a plurality of positioning terminals 9 pass through the resonant circuit and are sintered on the mounting base 1;

[0018] 2) The lower limit plate 2 is positioned by the positioning terminal 9 and fixed on the mounting base 1 by gluing, and the mounting boss 20 of the outer mounting frame 22 of the sensitive mass block structure is glued to the boss mounting holes 15 of the lower limit plate 2 and the upper limit plate 8;

[0019] 3) Multiple positioning terminals 9 pass through the lower limit plate 2, the sensitive mass block structure, and the upper limit plate 8. The output signals of the upper resonant beam 6 and the lower resonant beam 7 are connected to the positioning terminals 9 on the left and right half surfaces to achieve positioning and signal output; the housing 10 and the mounting base 1 are bonded together by sealant to achieve the sealing of the accelerometer.

[0020] Compared with the prior art, the present invention has the following beneficial effects: the present invention combines the design principles of the quartz flexible accelerometer pendulum and the resonant structure of the resonant accelerometer, adopts a double-mass block flexible support, and has a resonant accelerometer mass block sensitive structure with a stress isolation zone, inherits the characteristics of the flexible accelerometer with strong environmental adaptability, and adopts a resonant beam to be sensitive and output frequency signals, thereby realizing the digitization of the accelerometer output; it has the following advantages:

[0021] (1) The present invention adopts the design of mounting bosses on the upper and lower parts of the outer mounting frame, and the mounting bosses are closely matched with the lower limit plate and the upper limit plate, thereby improving the stability and sealing of the watch movement structure;

[0022] (2) The lower limit plate, upper limit plate and sensitive mass block structure of the present invention are all made of far-ultraviolet quartz glass with a linear expansion coefficient of 0.5ppm. The use of homogeneous materials reduces the temperature coefficient and long-term repeatability of the entire table, which is more conducive to model application and avoids the problem of poor temperature characteristics caused by different linear expansion coefficients of heterogeneous materials. It greatly reduces the temperature coefficient and temperature hysteresis of the product and improves temperature adaptability.

[0023] (3) The housing of the present invention is connected to the mounting base by sealing adhesive or laser welding, achieving a two-level seal between the watch movement and the entire watch, with a sealing performance of 1.0E-10Pa·m 3 / s, ensuring the long-term repeatability of the accelerometer's bias value.

[0024] (4) Since the present invention uses a double mass block to flexibly support the mass block, the stability of the mass block is improved, the mechanical environment adaptability of the resonant accelerometer is greatly improved, and the foundation for model application is laid.

[0025] (5) The sensitive mass block structure of the present invention is designed with a stress isolation zone, which reduces the stress interference of the mass block on the resonant beam and improves product stability.

[0026] (6) The present invention has a simple structure and its external dimensions can reach Smaller size meets the development trend of low cost and miniaturization.

[0027] (7) The structure and assembly of the present invention are easy to implement and can give full play to the advantages of the pendulum-type all-quartz resonant accelerometer with double flexible supports. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 It is a cross-sectional view of an accelerometer according to an embodiment of the present invention.

[0029] Figure 2 4 is a top view of a mounting base of an accelerometer according to an embodiment of the present invention.

[0030] Figure 3 1 and 2 are top and cross-sectional views of the upper and lower limit plates of the accelerometer according to the embodiment of the present invention.

[0031] Figure 4 4 is a top view of the mass block of the accelerometer according to the embodiment of the present invention.

[0032] Figure 5 4 is a cross-sectional view of the mass block of the accelerometer according to the embodiment of the present invention.

[0033] Figure 6 4 is a top view of a resonant beam of an accelerometer according to an embodiment of the present invention.

[0034] In the figure: 1-mounting base, 2-lower limit plate, 3-mass block, 4-mass block flexible support, 5-stress isolation area, 6-upper resonant beam, 7-lower resonant beam, 8-upper limit plate, 9-positioning terminal, 10-housing, 11-accelerometer mounting hole, 12-positioning terminal mounting hole, 13-accelerometer signal output hole, 14-positioning terminal sintering hole, 15-boss mounting hole, 16-upper resonant beam mounting groove, 17-lower resonant beam mounting groove, 18-lower resonant beam signal electrode lead-out layer, 19-resonant beam vibration limit plate, 20-mounting boss, 21-mass block swing tongue, 22-external mounting frame. DETAILED DESCRIPTION

[0035] The present invention is described in detail below in conjunction with the embodiments and drawings. It should be noted that the present invention is not limited to the following specific embodiments, and all equivalent changes made on the basis of the embodiments fall within the protection scope of the present invention.

[0036] like Figure 1-Figure 6 As shown, a double flexible support pendulum all-quartz resonant accelerometer includes a sensitive mass block structure consisting of a mass block 3, a mass block flexible support 4, and a stress isolation area 5, an upper resonant beam 6 is connected above the mass block 3, and a lower resonant beam 7 is connected below the mass block 3;

[0037] A lower limit plate 2 is connected below the sensitive mass block structure, and the lower limit plate 2 is connected to the mounting base 1; an upper limit plate 8 is connected above the sensitive mass block structure, and the lower limit plate 2, the sensitive mass block structure, and the upper limit plate 8 penetrate the positioning terminal 9; a shell 10 is provided outside the lower limit plate 2, the sensitive mass block structure, and the upper limit plate 8, and the shell 10 is connected to the mounting base 1;

[0038] The upper resonant beam 6 and the lower resonant beam 7 are electrically connected to the resonant circuit in the mounting base 1 via the positioning terminal 9, and transmit the signal to the resonant circuit.

[0039] The mounting base 1 is made of stainless steel, the resonant circuit is embedded in the mounting base 1, and four positioning terminals 9 are sintered on the mounting base 1 to provide an installation positioning reference for the accelerometer. Figure 2 As shown, the mounting base 1 is provided with four accelerometer mounting holes 11 , four positioning terminal mounting holes 12 , and six accelerometer signal output holes 13 .

[0040] The upper limit plate 8 and the lower limit plate 2 provide a mounting frame for the sensitive mass block structure and limit the displacement of the mass block swing tongue in the working state, thus playing a protective role; Figure 3 As shown, the upper limit plate 8 and the lower limit plate 2 have the same structure and are made of far-ultraviolet quartz glass. The left and right half surfaces inside each have two positioning terminal sintering holes 14 and the outer side is provided with three boss mounting holes 15.

[0041] like Figure 4 , Figure 5 As shown, the sensitive mass block structure is a core sensitive structure, and the material is far ultraviolet quartz glass, including a mass block 3, the mass block 3 is sensitive to external input acceleration and provides a mounting frame for the upper resonance beam 6 and the lower resonance beam 7, an upper resonance beam mounting groove 16 is provided above the fixed end of the mass block 3, and a lower resonance beam mounting groove 17 is provided below, and a lower resonance beam signal electrode lead-out layer 18 is symmetrically provided on the left and right above the fixed end of the mass block 3, and the fixed end of the mass block 3 is connected to the mass block flexible support 4 on both sides, and the mass block flexible support 4 and the mass block swing tongue 2 1 is connected, the function of the mass block flexible support 4 is to support the mass block swing tongue 21; a stress isolation zone 5 is provided between the mass block swing tongue 21 and the mass block flexible support 4, and the function of the stress isolation zone 5 is to reduce stress interference and improve product stability; three mounting bosses 20 for mounting the upper limit plate 8 and the lower limit plate 2 are respectively provided on the upper and lower surfaces of the outer mounting frame 22 of the periphery of the mass block 3; a resonance beam vibration limit plate 19 is provided on the outer side of the upper resonance beam 6 and the lower resonance beam 7 to limit the amplitude of the upper resonance beam 6 and the lower resonance beam 7 in the vibration working state.

[0042] The upper resonant beam 6 and the lower resonant beam 7 are as follows: Figure 6 As shown, based on the piezoelectric effect, when an external accelerometer is input, the mass block 3 converts the external input accelerometer into an applied force, and the upper resonant beam 6 and the lower resonant beam 7 are sensitive to the change in the applied force, and convert the change in force into a change in frequency. The frequency of the upper resonant beam 6 and the lower resonant beam 7 increases and decreases, and the frequency difference between the two resonant beams is linearly related to the input acceleration, thereby realizing acceleration measurement.

[0043] The housing 10 is bonded to the mounting base 1 by adhesive to achieve sealing of the accelerometer.

[0044] The positioning terminal 9 realizes the precise positioning of the upper limit plate 8 and the lower limit plate 2 and the lead-out of the signals of the upper resonance beam 6 and the lower resonance beam 7 through the positioning terminal through holes 14 of the upper limit plate 8 and the lower limit plate 2. The material is stainless steel with silver-plated outer surface.

[0045] The working principle of the accelerometer of the present invention is as follows:

[0046] The mass block tongue 21 acts as a sensitive element, converting the input acceleration signal into a force signal and transmitting it to the upper resonant beam 6 and the lower resonant beam 7; the upper resonant beam 6 and the lower resonant beam 7 sense the force change transmitted by the mass block tongue 21, and based on the piezoelectric effect, the frequency changes, and the frequency change has a certain linear relationship with the acceleration change. The upper resonant beam 6 and the lower resonant beam 7 are connected to the positioning terminal 9 through a gold wire, and the signal is transmitted to the resonant circuit. The resonant circuit detects the frequency change, and then solves and obtains the external input acceleration to realize the sensing measurement.

[0047] A method for assembling a double-flexure-supported pendulum-type all-quartz resonant accelerometer comprises the following steps:

[0048] 1) The mounting base 1 is placed on the positioning fixture as the installation reference of the entire accelerometer. Four positioning terminals 9 pass through the resonant circuit and are sintered on the mounting base 1 to provide an installation reference for the upper limit plate 8 and the lower limit plate 2;

[0049] 2) The lower limit plate 2 is positioned by the positioning terminal 9 and fixed on the mounting base 1 by gluing, and the mounting boss 20 of the external mounting frame 22 of the sensitive mass block structure is bonded to the boss mounting hole 15 of the lower limit plate 2 to achieve precise positioning and matching; the upper limit plate 8 is also etched with a boss mounting hole 15, and the mounting boss 20 of the external mounting frame 22 of the sensitive mass block structure is bonded to the boss mounting hole 15 of the upper limit plate 8 to achieve precise positioning and matching;

[0050] 3) Four positioning terminals 9 pass through the lower limit plate 2, the sensitive mass block structure, and the upper limit plate 8. The output signals of the upper resonant beam 6 and the lower resonant beam 7 are respectively welded to the positioning terminals 9 on the left and right half surfaces through gold wires to achieve positioning and signal output; the housing 10 and the mounting base 1 are matched by sealing adhesive bonding to achieve the sealing of the accelerometer.

Claims

1. A double flexible support pendulum all-quartz resonant accelerometer, characterized in that: It comprises a sensitive mass block structure consisting of a mass block (3), a mass block flexible support (4), and a stress isolation region (5); an upper resonant beam (6) is connected above the mass block (3), and a lower resonant beam (7) is connected below the mass block (3); A lower limit plate (2) is connected below the sensitive mass block structure, and the lower limit plate (2) is connected to the mounting base (1); an upper limit plate (8) is connected above the sensitive mass block structure, and the lower limit plate (2), the sensitive mass block structure, and the upper limit plate (8) penetrate the positioning terminal (9); a housing (10) is provided outside the lower limit plate (2), the sensitive mass block structure, and the upper limit plate (8), and the housing (10) is connected to the mounting base (1); The upper resonant beam (6) and the lower resonant beam (7) are electrically connected to the resonant circuit in the mounting base (1) via the positioning terminal (9) to transmit the signal to the resonant circuit.

2. The double flexible support pendulum all-quartz resonant accelerometer according to claim 1, characterized in that: The sensitive mass block structural material is made of far ultraviolet quartz glass, and comprises a mass block (3), wherein both sides of the fixed end of the mass block (3) are connected to mass block flexible supports (4), the mass block flexible supports (4) are connected to the mass block swing tongue (21), and a stress isolation area (5) is provided between the mass block swing tongue (21) and the mass block flexible support (4).

3. The double flexible support pendulum all-quartz resonant accelerometer according to claim 1, characterized in that: An upper resonance beam mounting groove (16) is provided above the fixed end of the mass block (3), and a lower resonance beam mounting groove (17) is provided below the fixed end; lower resonance beam signal electrode lead-out layers (18) are symmetrically provided on the left and right above the fixed end of the mass block (3); and resonance beam vibration limiting plates (19) are provided on the outer sides of the upper resonance beam (6) and the lower resonance beam (7).

4. The double flexible support pendulum all-quartz resonant accelerometer according to claim 1, characterized in that: The upper and lower surfaces of the outer mounting frame (22) around the mass block (3) are respectively provided with a plurality of mounting bosses (20) for mounting the upper limit plate (8) and the lower limit plate (2).

5. The double flexible support pendulum all-quartz resonant accelerometer according to claim 1, characterized in that: The mounting base (1) is made of stainless steel, the resonant circuit is embedded in the mounting base (1), and a plurality of positioning terminals (9) are sintered on the mounting base (1).

6. The double flexible support pendulum all-quartz resonant accelerometer according to claim 1, characterized in that: The upper limit plate (8) and the lower limit plate (2) have the same structure and are made of far ultraviolet quartz glass. The left and right half surfaces inside the upper limit plate (8) each have a positioning terminal sintering hole (14), and the outer side is provided with a plurality of boss mounting holes (15).

7. The double flexible support pendulum all-quartz resonant accelerometer according to claim 1, characterized in that: The upper resonant beam (6) and the lower resonant beam (7) are based on the piezoelectric effect. When an external accelerometer is input, the mass block (3) converts the external input accelerometer into an applied force. The upper resonant beam (6) and the lower resonant beam (7) are sensitive to the change in the applied force and convert the change in force into a change in frequency. The frequency of the upper resonant beam (6) and the lower resonant beam (7) increases and the frequency of the other decreases. The frequency difference between the two resonant beams is linearly related to the input acceleration, thereby realizing acceleration measurement.

8. The double flexible support pendulum all-quartz resonant accelerometer according to claim 1, characterized in that: The housing (10) is connected to the mounting base (1) via a sealing adhesive or laser welding, thereby achieving sealing of the accelerometer.

9. The double flexible support pendulum all-quartz resonant accelerometer according to claim 1, characterized in that: The positioning terminal (9) realizes the precise positioning of the upper limit plate (8) and the lower limit plate (2) and the lead-out of the signals of the upper resonance beam (6) and the lower resonance beam (7) through the positioning terminal through holes (14) of the upper limit plate (8) and the lower limit plate (2), and the material is a stainless steel material with a silver-plated outer surface.

10. The assembly method of a double flexible support pendulum-type all-quartz resonant accelerometer according to any one of claims 1 to 9, characterized in that: The following steps are involved: 1) The mounting base (1) is placed on a positioning tool, and a plurality of positioning terminals (9) pass through the resonant circuit and are sintered on the mounting base (1); 2) The lower limit plate (2) is positioned by means of a positioning terminal (9) and fixed to the mounting base (1) by means of adhesive bonding, and the mounting boss (20) of the external mounting frame (22) of the sensitive mass block structure is bonded to the boss mounting holes (15) of the lower limit plate (2) and the upper limit plate (8); 3) A plurality of positioning terminals (9) pass through the lower limit plate (2), the sensitive mass block structure, and the upper limit plate (8); the output signals of the upper resonant beam (6) and the lower resonant beam (7) are connected to the positioning terminals (9) on the left and right halves to achieve positioning and signal output; the housing (10) and the mounting base (1) are matched by bonding with a sealant to achieve sealing of the accelerometer.

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