Micro vibration gyro sensor unit and gyro with high MTBF

Abstract

The present invention provides a micro-vibration gyroscope sensitive unit with high MTBF and a gyroscope, which relates to the technical field of gyroscopes, can effectively increase the MTBF of the gyroscope, reduce costs and facilitate the realization of an integrated sensitive unit with a smaller volume; the sensitive unit includes a housing, a sensitive unit base and a resonator, the housing is fixedly connected to the sensitive unit base, the resonator is arranged inside the housing, the sensitive unit base is made of insulating material, and the sensitive unit base is provided with a plurality of conductive structures for transmitting piezoelectric signals; the conductive structure is sealedly connected to the sensitive unit base; a plurality of piezoelectric ceramics are provided on the vertical outer wall of the resonator; the piezoelectric ceramics are connected to the corresponding conductive structures through wires. The technical solution provided by the present invention is applicable to the process of designing and manufacturing gyroscopes.

Description

[Technical field]

[0001] The present invention relates to the technical field of gyroscopes, and in particular to a micro vibration gyroscope sensitive unit with high MTBF and a gyroscope. [Background technology]

[0002] The angular rate or angle of rotation can be measured by at least three physical phenomena, namely, conservation of angular momentum, the Sagnac effect, and the Coriolis force. In its most common form, a gyroscope is a device that uses one of these phenomena to measure or maintain orientation and angular velocity. The measurement of the gyroscope's angular rotation rate can be integrated over time to determine the change in the gyroscope's angular orientation. For example, gyroscopes can be used in applications such as inertial navigation systems (INS), inertial measurement units (IMU), platform stabilization, ground vehicle attitude control systems (ACS), drilling survey instruments, aircraft, ships, spacecraft, and / or other applications.

[0003] A Coriolis vibrating gyroscope (CVG) is a type of mechanical structure (resonator) gyroscope that couples one vibration mode to another (or multiple) modes under the action of an external Coriolis force. When only two resonant modes are involved, namely the primary and secondary vibration modes, the CVG becomes a single-axis angular rate (or angle) sensor.

[0004] CVGs represent an important inertial technology because they are amenable to miniaturization and suitable for mass production, especially when the resonator used to form the vibrating gyroscope is a micro-electro-mechanical system (MEMS) made from etched silicon or quartz wafers, in a similar manner to integrated circuits (ICs).

[0005] Vibratory gyroscopes have many advantages over gyroscopes that use conservation of angular momentum (i.e., rate gyroscopes, rate integrating gyroscopes, floating gyroscopes, dynamically tuned gyroscopes (DTGs)) and gyroscopes that use the Sagnac effect (i.e., fiber optic gyroscopes, ring laser gyroscopes) in that they may be easier to produce, easier to assemble at a lower cost, smaller in size, and more stable to the operating environment (including vibration, shock, and temperature), ultimately allowing them to provide higher reliability and longer service life.

[0006] CVG can be designed as an open-loop or deep closed-loop negative feedback mode. In these two modes, the gyroscope is a rate gyroscope that directly measures the external input angular rate; it can also be designed as a full-angle mode, in which the gyroscope can measure the angle information based on the initial position.

[0007] Resonators of various forms or shapes can be used to form CVGs, including the housing and vibrating mass of the resonator. In terms of scale, these resonators can be large-scale (such as millimeter level) or micro-scale (such as micrometer-level MEMS). However, based on the analysis of processing accuracy and the resulting error mechanism, only fully symmetrical resonators with large scales can achieve navigation-level measurement accuracy.

[0008] The resonator is designed to be in the shape of a hemispherical shell. In the main mode, the lip edge of the resonator undergoes elliptical deformation, and the four wave nodes are 90° to each other. The second-order mode is also elliptical. The vibration shape of the second-order mode is obtained by rotating the first-order mode by 45°. The wave numbers of the two modes are 2. Assuming that the resonator is completely symmetrical and the resonant frequencies of the two modes are equal, when the first-order mode is perfectly excited, any input angular velocity in the Z-axis direction will generate a Coriolis force, which will cause the energy excited by the resonator to transition from the first-order mode to the second-order mode. In the full closed-loop feedback mode, the feedback force is used to balance or offset the second-order mode, thereby achieving that the feedback force is equal to the input Coriolis force and realizing the measurement of the input angular velocity. In the full-angle mode, the second-order mode can freely and unconstrainedly receive the energy transfer from the first-order mode. Through the control strategy, the energy to maintain the free oscillation of the resonator position is obtained. The first-order mode and the second-order mode form a new vibration shape. By measuring the wave nodes of the new vibration shape, the size of the input angle can be calculated.

[0009] Hemispherical shell Coriolis gyroscopes are usually made of metallized silicon dioxide (Northrop Grumman, Safran), and the electrode system formed between the resonator and the electrode carrier (also made of metallized silicon dioxide) under high vacuum is used to generate electrostatic force and capacitive detection signals to control the resonator and measure the rotation speed or net rotation angle. Because the system is relatively complex, bulky and difficult to produce, its price remains high, and for less demanding applications, requiring only tactical-grade performance (1h to 10 / hr) and smaller size, an axisymmetric design using metal pillars and piezoelectric transducers to drive and measure vibrations is proposed.

[0010] The hemispherical shell resonant gyroscope uses silicon-based materials (molten glass). The resonator usually works in a high vacuum environment and the glass is metallized. The resonator and electrodes form an electronic measurement system, which realizes the measurement of input angle rate or angle through electrostatic drive and capacitance measurement. Its disadvantages are complex structure, large size and difficult processing.

[0011] For tactical-level application requirements, a fully symmetrical metal resonator design is adopted, and a driving and measurement method based on piezoelectric ceramics is adopted.

[0012] The earliest use of a cylindrical structure was the START gyro in the 1980s, which used a metal cylinder with piezoelectric ceramics attached to the cylinder wall, near the edge of the top of the cylinder. A stem to hold the cavity was placed outside, in the center of its flat bottom. In 2005, an alternative design that was smaller and easier to assemble was proposed, this time with the support rod placed inside the cavity and all the PZT piezoelectric ceramics bonded to the outside of the resonator's flat bottom instead of to the outer curved surface of the cylinder wall. Once the resonator is attached to a sensing unit base and encapsulated under moderate vacuum, this structure forms a structure called a CVG sensing element (SE). Although the cylindrical resonator is relatively small for this particular case, with an outer diameter of about 25 mm, the final SE dimensions are about 25 mm in height and 39 mm in diameter of the sensing unit base. The total mass is just under 80 grams.

[0013] Figure 1 and Figure 3 The structure diagram of the prior art sensitive unit. The technology used in the sensitive unit base is to use a sealed glass and metal seal (i.e., a glass insulator is arranged around the metal terminal) to feed the conductor (pin) sealed from the outside into the SE. The diameter of these terminals and the surrounding glass insulator is at most 1 to 2 mm. They are soldered to a PCB, which is provided with a connector 10, passive and active components.

[0014] Glass-to-metal sealing technology has many advantages because it can withstand temperatures of several hundred degrees (≥400°C), can withstand frequent temperature cycles between extremely cold and extremely hot temperatures (e.g., -65°C to +150°C), and can withstand high pressure loads (e.g., 1000 bars). It is well known that the sealing fusion of glass and metal parts can achieve leak rates that are typically less than 10 -8 mbar.Ls -1 , or less than 10 -12 mbar.Ls -1 .

[0015] However, undetected microcracks within the glass seal during the manufacturing and control process will allow the external atmosphere to slowly but surely enter the resonator cavity (at this point, the resonator cavity is not completely sealed), which will inevitably change the functional parameters of the gyroscope (such as bias drift) over a long period of time. For space applications that require a service life of 15 years (such as telecommunication geosynchronous satellites, science, space travel), this is seen as a clear disadvantage. In addition, contamination and purity issues of the glass, as well as the brittleness of the glass in severe vibration and shock environments (such as in the aerospace industry), can also lead to cracks and crack propagation, as well as the loss of vacuum inside the SE. In the worst case, this can lead to user-level failures and a reduction in the mean time between failures of sensitive units.

[0016] The airtightness problem caused by the microscopic defects of the glass insulator 12 causes the parameters of the sensitive unit of the gyroscope to change, resulting in long-term drift errors. This is extremely unfavorable for use environments such as 15 years or longer. In addition, the aerospace use environment such as vibration and shock limits the MTBF of the sensitive unit.

[0017] The prior art uses eight terminals 4. The terminals 4 are arranged at equal angles along the circumference. Figure 2 It can also be seen that the terminals 4 are aligned one by one with the piezoelectric ceramics 2. Each pin is then connected to the corresponding piezoelectric ceramic 2 using wire bonds 5. Finally, in the middle of the front circuit board 8, a connector 10 is used to electrically connect the SE to the control electronics (not shown) which also provides the supply voltage. Figure 3 A pin definition scheme using a glass insulator technology is provided, that is, a glass insulator 12 is arranged on the periphery of the terminal 4 to isolate the terminal 4 from the sensitive unit base 3 .

[0018] Considering the miniaturization of the sensitive unit (SE), the size of the resonator 1 needs to be reduced to less than 10 mm. In this case, the radius of the circle containing all the terminals 4 should be followed and reduced to less than 10 mm. However, the size of the pins, the outer dimensions of the connector, and the passive / active components on the PCB 8 become the main obstacles to size reduction. Because it is difficult to arrange multiple pins + components in a small plane space.

[0019] Therefore, it is necessary to study a sensitive unit of a Coriolis gyroscope design suitable for miniaturization and having high MTBF and low production cost to address the deficiencies of the prior art and to solve or alleviate one or more of the above problems. [Summary of the invention]

[0020] In view of this, the present invention provides a sensitive unit and a gyroscope suitable for miniaturization and having a high MTBF and a low production cost of a Coriolis gyroscope design, which can effectively increase the MTBF of the gyroscope, reduce costs and facilitate the realization of a smaller integrated sensitive unit.

[0021] The present invention provides a micro-vibration gyroscope sensitive unit with high MTBF (Mean Time Between Failure), comprising a housing, a sensitive unit base and a resonator, wherein the housing is fixedly connected to the sensitive unit base, and the resonator is arranged inside the housing, and is characterized in that:

[0022] The sensitive unit base is made of insulating material, and a plurality of conductive structures for transmitting piezoelectric signals are arranged in the sensitive unit base; the conductive structures are sealed and connected to the sensitive unit base;

[0023] A plurality of piezoelectric ceramics are arranged on the vertical outer wall of the resonator; the piezoelectric ceramics are connected to the corresponding conductive structure through a wire.

[0024] According to the aspects described above and any possible implementation methods, an implementation method is further provided, wherein the conductive structure includes a wire arranged inside the sensitive unit base, a first conductive pin arranged on the inner surface of the sensitive unit base, and a second conductive pin arranged on the outer surface of the sensitive unit base; both ends of the wire are connected to the first conductive pin and the second conductive pin respectively; the first conductive pin and the second conductive pin are both sealedly connected to the sensitive unit base.

[0025] According to the above aspects and any possible implementation, there is further provided an implementation, wherein the sensitive unit base is a multi-layer ceramic packaging structure.

[0026] According to the above aspects and any possible implementation manner, an implementation manner is further provided, wherein a shape of a cross section of the multilayer ceramic packaging structure includes but is not limited to a circle, a regular octagon, and a triangle.

[0027] According to the aspects described above and any possible implementation method, an implementation method is further provided, wherein the resonator is in the shape of a high-foot wine glass, including a wine glass portion and an external support rod; one end of the support rod is fixedly connected to the bottom end of the wine glass portion, and the other end is fixedly connected to the base of the sensitive unit.

[0028] According to the aspects described above and any possible implementation method, an implementation method is further provided, wherein a mounting blind hole is provided on the base of the sensitive unit; a fixing point is provided between the outer end of the support rod and the mounting blind hole, and the fixing point is a bonding point or a welding point.

[0029] According to the above aspects and any possible implementation manner, there is further provided an implementation manner, wherein the number of the conductive structures is greater than or equal to the number of the piezoelectric ceramics.

[0030] According to the above aspects and any possible implementation, there is further provided an implementation, wherein the piezoelectric ceramics are evenly arranged on a vertical outer wall of the wine glass portion near one end of the support rod.

[0031] According to the above aspects and any possible implementation, there is further provided an implementation, wherein a plurality of grooves are provided on the outer periphery of the sensitive unit base, and external vibration dampers are provided in the grooves.

[0032] According to the above aspects and any possible implementation, there is further provided an implementation, wherein the external vibration absorber is a conductive or non-conductive damper structure with an I-shaped cross-section.

[0033] On the other hand, the present invention provides a micro-vibration gyroscope with high MTBF, characterized in that the gyroscope comprises a control circuit and any sensitive unit as described above, and the control circuit is connected to the sensitive unit through the outer end of the conductive structure.

[0034] Beneficial effects of the present invention:

[0035] The structure using a multi-layer ceramic package allows the removal of the metal post plus glass seal, leads and PCB used in the prior art, which increases MTBF, reduces cost and allows for smaller integrated sensitive unit designs.

[0036] The support rod of the resonator is fixedly connected to a whole non-conductive multilayer ceramic base by (for example, welding or bonding), and internal and external electrical signal connections are achieved through conductive pins.

[0037] Additional features and advantages of the present invention will be set forth in the following description, and in part will be apparent from the description, or may be learned through practice of the present invention. The advantages of the present invention will be realized and achieved through the structures particularly pointed out in the specification, claims and drawings of the present invention.

[0038] Of course, any product implementing the present invention does not necessarily need to achieve all of the above-mentioned technical effects at the same time.

Brief Description of the Drawings

[0039] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0040] Figure 1 Shows the elliptical deformation of the 2nd mode in an axisymmetric shell;

[0041] Figure 2 An embodiment of a prior art Coriolis gyroscope sensitive element (SE) is shown, comprising a cylindrical resonator cavity and its piezoelectric ceramic, its SE base with glass-to-metal seal, annular damper, circuit sealing cover, and front circuit board carrying connectors for connection to a control system (not shown);

[0042] Figure 3 Shows bottom and top views of a prior art Coriolis gyroscope sensitive element (SE) using a cylindrical resonator;

[0043] Figure 4 An embodiment of the present invention of a cylindrical resonator of a Coriolis gyroscope sensitive unit is shown, wherein the sensitive unit adopts a multi-layer ceramic package as a sensitive unit base;

[0044] Figure 5 A top view of a multi-layer ceramic package having a sensing unit base with a regular octagonal structure according to an embodiment of the present invention is shown;

[0045] Figure 6 An embodiment of the present invention is shown, in which the connection pins are integrated into a multi-layer ceramic package, which is used as a sensitive unit base of a cylindrical resonator of a Coriolis gyroscope sensitive unit;

[0046] Figure 7 Other embodiments of the present invention are shown in which a multilayer ceramic package is used as a SE base for a Coriolis gyroscope having mounting holes and a separate vibration damper.

[0047] Among them, in the figure:

[0048] 1. Resonator; 2. Piezoelectric ceramics; 3. Sensitive unit base; 4. Terminals; 5. Wire bonding; 6. User installation structure; 7. Vibration absorber; 8. Front circuit board; 9. Housing; 10. Connector; 11. Electronic components; 12. Glass insulator; 13. Circuit sealing cover; 14. Conductive pins; 15. Conductive structure; 16. Conductive coating. [Specific implementation method]

[0049] In order to better understand the technical solution of the present invention, the embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0050] It should be clear that the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0051] The terms used in the embodiments of the present invention are only for the purpose of describing specific embodiments, and are not intended to limit the present invention. The singular forms "a", "said" and "the" used in the embodiments of the present invention and the appended claims are also intended to include plural forms, unless the context clearly indicates other meanings.

[0052] The starting point of the present invention is to solve the above-mentioned problem, namely, the problem of airtightness caused by the reliability of the glass insulator; and the problem of the limitation of the size area of ​​the external pin for the small-sized sensitive unit.

[0053] The present invention provides a micro-vibration gyroscope sensitive unit with high MTBF, comprising:

[0054] The resonator 1 is in the shape of a high-foot wine glass with or without a base, and includes a wine glass portion and an external support rod; one end of the support rod is fixedly connected to the bottom end of the wine glass portion, and the other end is fixedly connected to the sensitive unit base 3; the sensitive unit base 3 is provided with a mounting blind hole, and a fixed connection point is provided between the outer end of the support rod and the mounting blind hole, and the fixed connection point is a bonding point or a welding point; the wine glass portion is a cavity with an opening at the cup mouth;

[0055] A plurality of piezoelectric ceramics 2, the piezoelectric ceramics 2 are fixedly connected to the outer wall of the resonator 1 and arranged equiangularly; preferably, the piezoelectric ceramics 2 are attached to the vertical wall at the bottom end of the wine glass portion of the resonator 1, that is, the vertical outer wall close to one end of the support rod;

[0056] The multi-layer non-conductive mounting base (i.e., the sensitive unit base 3, which is made of non-conductive material) comprises:

[0057] An installation blind hole is located at the center of the base, and the outer end of the support rod is fixedly connected to the installation blind hole;

[0058] A plurality of conductive structures 15, each of which comprises a first conductive pin arranged on the inner surface of the base, a second conductive pin arranged on the outer surface of the base, and a wire arranged inside the base for electrically connecting the first conductive pin and the second conductive pin; the first conductive pin and the second conductive pin are both multiple and correspond to each other one by one; the first conductive pin matches the number of the piezoelectric ceramic and is electrically connected to the piezoelectric ceramic; the first conductive pin is located on the surface of the sensitive unit base at the periphery of the blind hole; the second conductive pin can be used to electrically connect to the electronic component;

[0059] The vibration damper mounting groove is located at the outer periphery of the sensitive unit base, specifically at the outermost end of the sensitive unit base 3;

[0060] An external shock absorber 7 is mounted in the shock absorber mounting groove;

[0061] A circuit sealing cover 13 is fixedly connected to the top of the sensitive unit base 3 and is used to seal the front circuit board 8;

[0062] The vacuum-sealed housing 9 is fixedly connected below the sensitive unit base 3 and outside the resonator 1 to seal the resonator 1 .

[0063] Furthermore, the first conductive pin on the inner surface of the sensing unit base 3 is electrically connected to the piezoelectric ceramic 2 through the wire bonding 5 .

[0064] Furthermore, the shape of the sensing unit base 3 includes but is not limited to a circle, a regular octagon and a triangle.

[0065] Furthermore, the active / passive element for adapting to the high impedance signal from the piezoelectric ceramic 2 is mounted on the outer surface of the sensitive unit base 3, that is, electrically connected to the second conductive pin.

[0066] Furthermore, active / passive elements for adapting to high impedance signals from the piezoelectric ceramic 2 are mounted on the inner surface of the sensitive unit base 3 , that is, the surface on the same side as the resonator 1 .

[0067] Further, the number of the piezoelectric ceramics 2 is a multiple of 2, and is divided into two piezoelectric ceramic groups of the same number, including a first-order mode driving / measuring piezoelectric ceramic group and a second-order mode driving / measuring piezoelectric ceramic group.

[0068] Furthermore, a conductive pad is bonded to the sensitive unit base.

[0069] Further, the second conductive pins are distributed on the outer surface of the sensing unit base, or are grouped in the same area in a manner similar to the pins of the connector 10 .

[0070] Furthermore, the circuit sealing cover 13 and the vacuum-sealed housing 9 are both made of FeNiCo and brazed to the sensing unit base 3 using a copper-silver brazing joint.

[0071] Furthermore, the external vibration absorber 7 is a conductive or non-conductive damper structure with an I-shaped cross section.

[0072] Further, the I-shaped damper structure has an I-shaped double-conical cross-section.

[0073] Further, the cross section of the shock absorber mounting groove is a shape matching the I-shaped double-conical cross section.

[0074] Further, a single buffer providing electrical and mechanical insulation is inserted into the mounting hole of the ceramic sensing unit base, and its I-shaped cross section can be straight or double-conical. If it is double-conical, the sensing unit base mounting hole is consistent with this design.

[0075] A specific embodiment of the present invention is as follows:

[0076] A sensitive unit of a Coriolis gyroscope design suitable for miniaturization, high MTBF and low production cost, includes a high-foot red wine glass-shaped resonator 1, the resonator includes a wine glass portion and a support rod located outside the wine glass portion, one end of the support rod is fixedly connected to the outside of the bottom of the wine glass portion; the high-foot red wine glass-shaped resonator may or may not include a high-foot wine glass base. A plurality of piezoelectric ceramics 2 are attached to the vertical wall at the bottom of the wine glass portion, that is, the vertical cylindrical wall of the wine glass portion close to one end of the support rod. The number of piezoelectric ceramics 2 is a multiple of 2, preferably 8, and is divided into 2 groups, each group having the same number of piezoelectric ceramics. One group is responsible for driving and measuring the first-order mode, and the other group is responsible for driving and measuring the second-order mode. The resonator support rod is fixedly connected (for example, welded, bonded) to a sensitive unit base 3 composed of an integral non-conductive multilayer ceramic, and internal and external electrical signal connections are achieved through pads.

[0077] Figure 4 The preferred embodiment of the present invention is shown. The Coriolis gyroscope sensitive unit includes a goblet-shaped resonator 1, which includes a goblet portion and a support rod disposed outside the goblet. A plurality of piezoelectric ceramics 2 are attached to the outer diameter of the goblet portion of the resonator at equal angles along the circumference, specifically to the vertical peripheral wall of the goblet portion near one end of the support rod. This structure is particularly advantageous for avoiding a decrease in the quality factor of the resonant cavity and improving performance. These piezoelectric ceramics 2 are used to drive and measure the first and second order resonant modes of the resonator. To this end, the top and bottom parallel surfaces of these piezoelectric ceramics 2 are metallized to make these surfaces conductive and allow electrical connection using wire bonding 5 connections.

[0078] The number of piezoelectric ceramics 2 is divided into two groups, and the number of piezoelectric ceramics in each group is the same. One group is responsible for the first-order mode, and the other group is responsible for the second-order mode.

[0079] The preferred arrangement uses eight piezoelectric ceramics 2, made of PZT ceramic material with a medium to high quality factor to maintain the quality factor of the resonator, and having a high piezoelectric charge coefficient (d ij ). When there are 8 piezoelectric ceramics, one piezoelectric ceramic is evenly distributed every 45 degrees, that is, the angle between any two adjacent piezoelectric ceramics 2 and the central axis of the resonator 1 is 45 degrees. In order to facilitate the assembly of the piezoelectric ceramics 2, the curved surface of the resonator 1 (i.e., the vertical peripheral wall of the wine glass part) can be processed to remove the curvature at the installation position so that it has a plane for the installation of the piezoelectric ceramics 2 to ensure the flat installation of the piezoelectric ceramics 2.

[0080] The resonator support rod is mounted (for example, welded or bonded) to a multilayer ceramic package structure used as a base 3 of the sensitive unit. Figure 5 A top view of an example of a multi-layer ceramic package structure.

[0081] exist Figure 5 For example, a sensitive unit is assumed in which eight piezoelectric ceramics 2 are attached to a resonator 1, and the base 3 of the sensitive unit is circular as a whole, with a regular octagon in the center, forming eight straight edges, each of which is provided with a first conductive pin, and each first conductive pin is parallel to the piezoelectric ceramic corresponding thereto. A wire bonder used in integrated circuit microelectronics can be used to connect a wire bond 5 between each first conductive pin and each piezoelectric ceramic.

[0082] Of course, the regular octagonal structure in the center of the multilayer ceramic package structure can be of different shapes, such as a circle, because the diameter of the wire bonding 5 connected thereto needs to be very small (e.g., 25 μm), so a first conductive pin with a relatively small area can be accepted. A plurality of conductive structures 15 are provided inside the multilayer ceramic package base, which can conduct the piezoelectric signal from the inner surface of the ceramic structure to the outer surface. The conductive structure 15 includes a wire hole, a conductive wire or a conductive coating provided in the wire hole, a first conductive pin provided on the inner surface of the sensitive unit base, and a second conductive pin provided on the outer surface of the sensitive unit base (the specific form of the conductive pin can be a pad). The first conductive pin and the corresponding second conductive pin are connected by a conductive wire or a conductive coating located between the two to achieve continuous conductivity between the two. The number of conductive structures is consistent with the number of piezoelectric ceramics, and corresponds one to one. The first conductive pin is used to electrically connect to the corresponding piezoelectric ceramic 2 through the wire bonding 5, and the second conductive pin is used to electrically connect to the front circuit board 8 provided outside the sensitive unit base 3. The first conductive pin and the second conductive pin are both made of conductive material. The connection between the conductive structure 15 and the sensitive unit base 3 meets the sealing requirements.

[0083] The conductive structure 15 transmits piezoelectric signals in the non-conductive sensitive unit base 3, and is directly welded to the electronic component 11 on the surface of the sensitive unit base 3 through the second conductive pin on the surface of the ceramic material. The conductive pin 14 includes a first conductive pin arranged on the inner surface of the sensitive unit base 3 and a second conductive pin arranged on the outer surface of the sensitive unit base 3. The first conductive pin is usually evenly arranged and corresponds to the piezoelectric ceramic one by one, and the second conductive pin can be arranged as needed, evenly arranged or integrated in a certain area on the outer surface of the sensitive unit base, so as to achieve electrical connection with the electronic component.

[0084] For example, in Figure 4 In the embodiment, these electronic components 11 are directly mounted on the outer surface of the sensing unit base 3, i.e., on the side opposite to the resonator. If space permits, active components particularly suitable for adjusting the impedance of the sensing piezoelectric signal are placed closer to the second conductive pins, and under the sealing effect of the circuit sealing cover 8, they become electronic components in the airtight sealed space.

[0085] In terms of assembly process, the resonator support rod can be assembled to the sensitive unit base 3 of the multilayer ceramic package by bonding or welding. In the case of welding, it is recommended to appropriately set the conductive coating 16 in the mounting blind hole, such as Figure 5 shown.

[0086] Conductive pins 14 integrated into the base 3 of the multilayer ceramic package allow the SE to be connected to its external control electronics. These pins can be distributed on the outer surface of the multilayer ceramic SE base or grouped in the same area in a similar manner to the pins of a connector, such as Figure 6 shown.

[0087] In order to prevent exposure to moisture, handling and various mechanical damages, a circuit sealing cover 13 can be provided on the outer surface of the multilayer ceramic package sensitive unit base 3 to protect the electronic components 11 provided on the outer surface of the multilayer ceramic package sensitive unit base. The circuit sealing cover 13 can be brazed to the alumina package (i.e., ceramic package) using a copper-silver brazing joint. The material of the circuit sealing cover can be FeNiCo or other materials. The circuit sealing cover 13 can be fixed by gluing it to the sensitive unit base 3.

[0088] The shell 9 covers the periphery of the resonator 1 and is fixedly connected to the sensitive unit base 3. The material of the shell 9 can be FeNiCo material, or other materials that can achieve sealed packaging with the sensitive unit base 3. The shell 9 is brazed to the sensitive unit base 3 (the sensitive unit base is a multi-layer ceramic packaging structure, and the ceramic material is generally alumina, and can also be other materials, such as aluminum nitride) with a copper-silver brazing joint, so as to seal the resonator 1 under medium vacuum.

[0089] The multilayer ceramic package sensitive unit base 3 includes a plurality of annular grooves on its outer diameter (the number of the grooves corresponds to the number of the external vibration dampers 7 and is determined according to the actual installation requirements) for installing therein an I-shaped external vibration damper 7 (i.e., a damping structure) made of a silicon-based or non-conductive damping material, the cut-off frequency of which is much lower than the first-order and second-order modal frequencies and higher than the measurement bandwidth obtained when the SE is connected to the control loop electronic equipment.

[0090] The cross section of the annular groove at the outer diameter of the sensor unit base 3 is preferably bi-conical to allow an annular bi-conical damper to be installed therein. This is expected to improve the robustness to shock and vibration along the Z axis.

[0091] When the sensing unit base 3 is clamped on the user mounting structure 6, the vibration damper 7 is located between the two and plays a vibration damping effect when the sensing unit is working, and can maintain the position and alignment of its sensing axis under any operating mechanical and thermal conditions.

[0092] Figure 7The sensing unit base 3 of the multilayer ceramic package can be in different shapes, for example, square, triangular, circular, octagonal, polygonal, or other shapes with mounting holes. For the design of a specific sensing unit base, a single vibration damper 7 is considered, whose I-shaped cross section can be straight or bi-conical. The vibration damper 7 and the damping ring are mounted in the same manner as the vibration damper and the vibration damper mounting groove.

[0093] Compared with the prior art, the advantages or features of the present invention are:

[0094] 1) The support rod is outside the resonator cavity, so that there is enough space inside the resonator for easy processing, and there is more space for a tool (such as a milling cutter) to process the inner cavity of the resonator, so that a smaller resonator can be designed.

[0095] 2) The piezoelectric ceramic elements can be arranged more flexibly.

[0096] 3) The piezoelectric ceramics are arranged on the periphery or end surface of the wine glass portion of the resonator, thus avoiding the reduction of the quality factor of the resonator caused by pasting the piezoelectric ceramics.

[0097] 4) There is a groove on its outer diameter, and the groove is equipped with a type I external vibration damper.

[0098] 5) Installation positioning hole clamping relationship: The relationship between the embedded external vibration absorber, the resonator, and the sensitive unit base facilitates installation and positioning, while providing a vibration reduction environment for the sensitive unit.

[0099] The above is a detailed introduction to a micro gyroscope sensitive unit and a gyroscope with high MTBF provided by the embodiment of the present application. The description of the above embodiment is only used to help understand the method and core idea of ​​the present application; at the same time, for those skilled in the art, according to the idea of ​​the present application, there will be changes in the specific implementation method and application scope. In summary, the content of this specification should not be understood as limiting the present application.

[0100] For example, certain words are used in the specification and claims to refer to specific components. Those skilled in the art should understand that hardware manufacturers may use different nouns to refer to the same component. This specification and claims do not use differences in names as a way to distinguish components, but use differences in the functions of components as the criteria for distinction. As mentioned throughout the specification and claims, "including" and "comprising" are open-ended terms, so they should be interpreted as "including / including but not limited to". "Approximately" means that within an acceptable error range, those skilled in the art can solve the technical problem within a certain error range and basically achieve the technical effect. The subsequent description of the specification is a preferred embodiment of the present application, but the description is for the purpose of illustrating the general principles of the present application, and is not used to limit the scope of the present application. The scope of protection of the present application shall be determined by the definition of the attached claims.

[0101] It should also be noted that the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a product or system including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such a product or system. In the absence of more restrictions, the elements defined by the sentence "comprises a ..." do not exclude the existence of other identical elements in the product or system including the elements.

[0102] It should be understood that the term "and / or" used in this article is only a description of the association relationship of associated objects, indicating that there can be three relationships. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in this article generally indicates that the associated objects before and after are in an "or" relationship.

[0103] The above description shows and describes several preferred embodiments of the present application, but as mentioned above, it should be understood that the present application is not limited to the form disclosed herein, and should not be regarded as excluding other embodiments, but can be used in various other combinations, modifications and environments, and can be modified within the scope of the application concept described herein through the above teachings or the technology or knowledge of the relevant field. The changes and modifications made by those skilled in the art do not deviate from the spirit and scope of the present application, and should be within the scope of protection of the claims attached to the present application.

Claims

1. A micro vibrating gyroscope sensitive unit with high MTBF, comprising a housing, a sensitive unit base and a resonator, wherein the housing is fixedly connected to the sensitive unit base, and the resonator is arranged inside the housing, characterized in that: The sensitive unit base is made of insulating material, and a plurality of conductive structures for transmitting piezoelectric signals are arranged in the sensitive unit base; the conductive structures are sealed and connected to the sensitive unit base; The vertical outer wall of the resonator is provided with 8 piezoelectric ceramics, and the angle between any two adjacent piezoelectric ceramics and the central axis of the resonator is 45 degrees; the piezoelectric ceramics are connected to the corresponding conductive structure through a wire, The conductive structure includes a conductive wire disposed inside the sensitive unit base, a first conductive pin disposed on the inner surface of the sensitive unit base, and a second conductive pin disposed on the outer surface of the sensitive unit base; two ends of the conductive wire are respectively connected to the first conductive pin and the second conductive pin; The sensitive unit base is a multi-layer ceramic packaging structure; a plurality of grooves are arranged on the outer periphery of the sensitive unit base, and an external vibration damper is arranged in the groove; the external vibration damper is a conductive or non-conductive damper structure with an I-shaped cross section; The resonator is in the shape of a goblet, including a goblet portion and an external support rod; one end of the support rod is fixedly connected to the bottom end of the goblet portion, and the other end is fixedly connected to the sensitive unit base; a mounting blind hole is provided on the sensitive unit base; Wherein, a fixing point is provided between the outer end of the support rod and the mounting blind hole, and the fixing point is a bonding point or a welding point.

2. The micro-vibration gyro sensitive unit with high MTBF according to claim 1, characterized in that: The cross-section of the multilayer ceramic package structure includes a circle, a regular octagon and a triangle.

3. The micro-vibration gyro sensitive unit with high MTBF according to claim 1, characterized in that: The number of the conductive structures is not less than the number of the piezoelectric ceramics.

4. The micro-vibration gyro sensitive unit with high MTBF according to claim 1, characterized in that: The piezoelectric ceramics are evenly arranged on the vertical outer wall of the wine glass portion near one end of the supporting rod.

5. A micro vibrating gyroscope with high MTBF, characterized in that: The gyroscope comprises a control circuit and a sensitive unit as claimed in any one of claims 1 to 4, wherein the control circuit is connected to the sensitive unit via an outer end of the conductive structure.

Images