Piezoelectric force and acceleration compound sensor and assembling method thereof

Abstract

The application discloses a piezoelectric force and acceleration composite sensor and an assembling method thereof, and belongs to the technical field of sensors. The sensor shell comprises a mounting base, a lower shell and an upper shell, the lower shell is threadedly connected below the mounting base, and a force detection core body is clamped between the lower shell and the mounting base. A connecting column is arranged at the center of the lower shell, the upper end of the connecting column penetrates through the mounting base and is threadedly connected with the center column of an acceleration core body, and the acceleration detection core body is assembled on the center column and located in the upper shell. The application integrates force and acceleration double-channel detection, solves the problems of multiple sensor installation space occupation, asynchronous signal sampling and time axis dislocation, truly reflects the parameter coupling relationship, reduces the influence on the mechanical characteristics of a measured structure, and reduces the measurement error. The assembling adopts a double-thread pre-tightening structure, improves the pre-tightening force stability and the front linear degree of the sensor range, and the overall structure is compact, the signal synchronization is strong, the measurement precision is high, and the application is suitable for high-precision force and acceleration synchronous measurement occasions.

Description

Technical Field

[0001] This invention relates to the field of sensors, and in particular to a piezoelectric force and acceleration composite sensor and its assembly method. Background Technology

[0002] In the field of high-end precision manufacturing, equipment operates under complex conditions, often requiring simultaneous monitoring of two types of parameters: force and acceleration. Examples include the coupled acquisition of vibration and load on engine blades, the measurement of impact response of rail transit bogies, and the joint diagnosis of cutting force and vibration in precision machine tools. The synchronicity and accuracy of parameter measurements are directly related to equipment condition assessment and safe operation.

[0003] Traditional measurement schemes often employ independent deployment of force sensors and accelerometers. While this can achieve parameter acquisition, it has significant limitations: independent operation of multiple sensors can easily lead to asynchronous sampling clocks and signal transmission delays, resulting in misalignment of the time axis of force and acceleration data, which cannot accurately reflect the parameter coupling relationship; the structure of the device under test is compact, and the installation of multiple sensors occupies a large space, which can also change the mechanical properties of the structure under test and introduce additional measurement errors.

[0004] Existing piezoelectric sensing products still have significant technical defects. The force measurement modules mostly adopt force ring preload welding packaging, and the preload force is only provided by tiny welds, which makes it difficult to control the linearity in the first 20% of the measurement range and results in insufficient measurement accuracy. At the same time, this packaging method cannot withstand large-scale vibration environment and cannot meet the modal testing requirements under high impact and strong vibration conditions. Summary of the Invention

[0005] This invention addresses the problems of asynchronous sampling clocks in current sensors and the difficulty in controlling the linearity of the first segment of the measurement range in traditional packaging forms by providing a piezoelectric force and acceleration composite sensor.

[0006] To solve the above problems, the technical solution adopted by the present invention is a piezoelectric force and acceleration composite sensor, which includes a sensor housing. An acceleration detection core and a force detection core are provided in the sensor housing. The sensor housing includes a mounting base. A lower housing is installed below the mounting base by means of a thread. The top surface of the lower housing has a lower mounting cavity. The force detection core is clamped between the lower housing and the mounting base. A connecting column is provided at the center of the inner bottom surface of the lower mounting cavity. The upper end of the connecting column penetrates above the mounting base. The upper end of the connecting column is installed with an acceleration core central column by means of a thread. The acceleration core central column presses against the upper surface of the mounting base. The acceleration detection core is installed on the acceleration core central column. An upper housing is further provided above the mounting base. The bottom surface of the upper housing has an upper mounting cavity. The acceleration detection core is located in the upper mounting cavity. This sensor integrates force detection and acceleration detection, eliminates the problem of space occupation caused by the independent installation of multiple sensors, avoids signal sampling asynchronization and time-axis misalignment, enables the coupling relationship between force and acceleration to be truly reflected, reduces the influence of installation on the mechanical properties of the measured structure, and reduces measurement errors. At the same time, the lower housing and the mounting base are connected by a thread, and an acceleration core central column is provided at the upper end of the connecting column. The double pre-tightening effect is achieved by using their thread connection, greatly improving the stability of the pre-tightening force and the front-end linearity of the sensor.

[0007] As a preferred implementation of a piezoelectric force and acceleration composite sensor, the force detection core includes a force measuring electrode sheet. Force measuring piezoelectric quartz is provided on both the upper and lower sides of the force measuring electrode sheet. The force measuring electrode sheet and the force measuring piezoelectric quartz are both annular and surround the lower end of the connecting column. The bilateral piezoelectric quartz opposed structure can improve the charge output amplitude, make the force measuring signal maintain a uniform response within the full range, and the annular structure forms a coaxial assembly relationship with the connecting column, ensuring that the external force is transmitted along the central axis of the sensor, reducing the interference of lateral components on the force measuring result, and improving the force measuring stability and consistency.

[0008] As a preferred implementation of a piezoelectric force and acceleration composite sensor, a force core insulating ring is further provided between the force measuring electrode sheet and the connecting column. The inner peripheral surface of the force core insulating ring contacts the outer peripheral surface of the connecting column, and the outer peripheral surface of the force core insulating ring contacts the inner edges of the force measuring electrode sheet and the force measuring piezoelectric quartz. Let the thickness of the force core insulating ring be d, the thickness of the force measuring piezoelectric quartz be h, and the thickness of the force measuring electrode sheet be H, satisfying h + H < d < H + 2h. The force core insulating ring can achieve electrical isolation between the force detection core and the metal connecting column, avoid signal loop leakage and interference. The defined thickness relationship makes the insulating ring not participate in the force, ensuring that the pre-tightening force acts entirely on the force measuring piezoelectric quartz, and at the same time restricting the radial displacement of the force measuring piezoelectric quartz and the force measuring electrode sheet, maintaining the constant force application position.

[0009] As a preferred embodiment of a piezoelectric force and acceleration composite sensor, the acceleration detection core includes an acceleration insulating sheet, an acceleration electrode sheet, a piezoelectric ceramic, and a mass block. The cross-section of the central column of the acceleration core is rectangular. Two of each of the acceleration insulating sheet, acceleration electrode sheet, piezoelectric ceramic, and mass block are disposed on a set of opposite sides of the central column. These components are stacked sequentially along the direction away from the mass block. The double-sided symmetrical shear structure enhances the anti-lateral interference capability of acceleration detection, balances the inertial force, and improves signal output consistency. The rectangular cross-section of the central column provides positioning surfaces for each component, reducing assembly deviations and adapting to continuous detection under high-frequency vibration conditions.

[0010] As a preferred embodiment of a piezoelectric force and acceleration composite sensor, the side of the mass block facing away from the central column of the acceleration core is an arc-shaped surface. A fastening ring is provided on the outer periphery of both mass blocks, pressing the mass blocks, acceleration electrode plates, and acceleration insulating plates firmly onto the central column of the acceleration core. The fastening ring provides a continuous and stable preload to the acceleration detection core, ensuring a tight fit between the various components and preventing gaps and loosening during vibration. The arc-shaped surface structure ensures that the clamping force of the fastening ring is evenly distributed circumferentially, guaranteeing the stability of the piezoelectric ceramic under stress and extending the core's service life.

[0011] As a preferred implementation of a piezoelectric force and acceleration composite sensor, the bottom surface of the mounting base is provided with an annular groove, the center of which is provided with a central mounting boss. The inner wall of the annular groove is provided with a first internal thread, and the outer periphery of the upper edge of the lower housing is provided with a first external thread. The lower housing is screwed into the annular groove. The bottom surface of the lower mounting cavity is provided with a lower mounting boss, and the connecting post is located at the center of the lower mounting boss. The force detection core is clamped between the central mounting boss and the lower mounting boss. The threaded connection allows for precise control and application of high preload, ensuring the force-measuring core maintains good linearity even under high-range vibration conditions. The central mounting boss and the lower mounting boss form a defined force-bearing surface, ensuring the preload is evenly applied to the force-measuring core, replacing the traditional welding preload method and improving the structural reliability of the force-measuring module.

[0012] As a preferred implementation of a piezoelectric force and acceleration composite sensor, the top surface of the mounting base is provided with a primary mounting boss. The outer periphery of the primary mounting boss has a second external thread, and the lower end of the inner wall of the upper mounting cavity has a second internal thread. The second external thread and the second internal thread are connected in a mating manner. A secondary mounting boss is provided at the center of the top surface of the primary mounting boss, and the central column of the acceleration core abuts against the upper surface of the secondary mounting boss. The threaded fit improves the connection strength between the upper housing and the mounting base, ensuring that the housing does not loosen under high impact loads. The secondary mounting boss provides a fixed support surface for the central column of the acceleration core, ensuring that the installation height and axial position of the acceleration detection core remain consistent, thus improving the repeatability of the signal output.

[0013] As a preferred implementation of a piezoelectric force and acceleration composite sensor, the mounting base is a regular hexagonal prism structure. The outer circumference of the mounting base has two output connectors, which connect to the acceleration detection core and the force detection core, respectively. The regular hexagonal prism structure facilitates on-site installation and fastening. The dual output connectors enable independent output of force and acceleration signals, ensuring that the two signals do not interfere with each other during transmission. This allows direct connection to multi-channel acquisition equipment, simplifying system wiring.

[0014] On the other hand, the present invention also provides an assembly method for the above-mentioned piezoelectric force and acceleration composite sensor, comprising the following steps: S1. Install the force detection core on the lower housing, install the mounting base on the upper part of the lower housing by thread and apply preload, and pass the connecting column through the mounting base; S2. Install the acceleration detection core on the acceleration core center column, then thread the acceleration core center column with the acceleration detection core onto the upper end of the connecting column and apply a preload. S3. Install the upper housing onto the mounting base using threads; S4. Weld and fix the joints between the mounting base and the upper shell and between the mounting base and the lower shell.

[0015] This method employs a thread pre-tightening followed by welding sealing, which enables the force measuring core to obtain a stable and sufficient preload, meeting the requirements of large-scale force and vibration force testing. The welding process improves the sealing performance and structural integrity of the shell. The assembly steps are clear, enabling standardized operations and improving product consistency.

[0016] As a preferred implementation of this assembly method, in step S2, an acceleration core installation fixture is used. The fixture includes a connecting plate with two stakes on its bottom surface, spaced 180° apart. The cross-sectional shape of the stakes matches the shape of the space enclosed by the acceleration core's central column, fastening ring, and mass block, allowing the stakes to be inserted into this space to tighten the central column. The top surface of the connecting plate also has a hexagonal prism-shaped operating part. This specialized fixture enables the tightening of the central column without contacting the piezoelectric element and mass block, avoiding damage to the core during assembly. The matching of the stakes with the assembly space ensures uniform torque transmission, achieving the designed preload, and improving assembly efficiency and product qualification rate.

[0017] As can be seen from the above technical solutions, the piezoelectric force and acceleration composite sensor of this invention, through its integrated coaxial structure, can simultaneously detect force and acceleration signals, effectively solving the problems of limited installation space for multiple sensors, asynchronous signal sampling, and time axis misalignment. It accurately reflects the parameter coupling relationship and reduces measurement errors. The use of a threaded connection to achieve a double pre-tightening structure significantly improves the stability of the pre-tightening force and the linearity of the sensor's initial measurement range, meeting the requirements for large-range vibration force testing. The double-sided piezoelectric quartz opposing structure enhances the charge output amplitude, ensuring uniform force response and force coaxiality. The insulating ring of the force core provides electrical isolation and limits the force path, avoiding signal interference and radial displacement of components. The acceleration detection core adopts a double-sided symmetrical shear arrangement, exhibiting strong anti-lateral interference capability, good output consistency, and suitability for high-frequency vibration conditions. The fastening ring provides stable preload to the accelerometer core, while the arc-shaped mass block ensures uniform circumferential force distribution, extending the core's service life. The mounting base and upper / lower housings utilize a threaded connection with a boss positioning structure, improving connection strength and preload accuracy, replacing traditional welding preload methods, and enhancing overall structural reliability. Dual independent output connectors provide isolated signal output, and the regular hexagonal prism shape facilitates on-site installation. The assembly method employs threaded preload followed by welding sealing, enabling stable application of large-range preload while ensuring housing sealing and integrity. The standardized process facilitates standardized production. Dedicated installation fixtures allow for non-destructive assembly of the accelerometer core, ensuring precise preload application and improving assembly efficiency and product qualification rate. Attached Figure Description

[0018] To more clearly illustrate the technical solution of this patent, the drawings used in the description will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this patent. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0019] Figure 1 This is a schematic diagram of the external structure of a specific embodiment of the present invention.

[0020] Figure 2 This is a cross-sectional view of a specific embodiment of the present invention.

[0021] Figure 3 This is a schematic diagram of the mounting base in a specific embodiment of the present invention. Figure 1 .

[0022] Figure 4 This is a schematic diagram of the mounting base in a specific embodiment of the present invention. Figure 2 .

[0023] Figure 5 This is a schematic diagram of the upper shell structure in a specific embodiment of the present invention.

[0024] Figure 6 This is a schematic diagram of the lower shell structure in a specific embodiment of the present invention.

[0025] Figure 7 This is a top view schematic diagram of the acceleration detection core in a specific embodiment of the present invention.

[0026] Figure 8 This is a schematic diagram of the accelerometer core mounting fixture in a specific embodiment of the present invention.

[0027] Figure 9 This is a schematic diagram illustrating the use of the accelerometer core mounting fixture in a specific embodiment of the present invention.

[0028] Explanation of main figure symbols 01. Acceleration detection core, 02. Force detection core, 03. Upper mounting cavity, 04. Lower mounting cavity, 1. Piezoelectric ceramic, 2. Mass block, 3. Fastening ring, 4. Upper housing, 41. Second internal thread, 5. Acceleration electrode plate, 6. Acceleration insulating plate, 7. Acceleration core center post, 8. Mounting base, 81. Annular groove, 82. Middle mounting boss, 83. First-stage upper mounting boss, 84. Second external thread, 85. Second-stage upper mounting boss, 86. First internal thread, 9. Output connector, 10. Force measuring piezoelectric quartz, 11. Force measuring electrode plate, 12. Lower housing, 121. Connecting post, 122. Lower mounting boss, 123. First external thread, 13. Force core insulating ring, 14. Acceleration core mounting fixture, 141. Connecting plate, 142. Insertion post, 143. Operating part. Detailed Implementation

[0029] To make the objectives, features, and advantages of this patent more apparent and understandable, the technical solutions of this patent will be clearly and completely described below with reference to the accompanying drawings of the specific embodiments. Obviously, the embodiments described below are only some embodiments of this patent, and not all embodiments. Based on the embodiments of this patent, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this patent.

[0030] Example 1 like Figure 1 , 2 As shown, a piezoelectric force and acceleration composite sensor includes a sensor housing. An acceleration detection core 01 and a force detection core 02 are disposed inside the sensor housing. The sensor housing is composed of a mounting base 8, an upper shell 4 and a lower shell 12. The top surface of the upper shell 4 and the bottom surface of the lower shell 12 are provided with threaded holes for connecting external structures. The mounting base 8 is connected to the lower housing 12 via a threaded connection. The lower housing 12 has a lower mounting cavity 04 on its top surface. The force detection core 02 is pressed and fixed between the lower housing 12 and the mounting base 8. A connecting post 121 is integrally provided at the bottom center of the lower mounting cavity 04. The upper end of the connecting post 121 passes upward through the mounting base 8 and is fastened to the acceleration core center post 7 via a thread. The lower end face of the acceleration core center post 7 is pressed against the upper surface of the mounting base 8. The acceleration detection core 01 is fixedly assembled on the acceleration core center post 7. The upper housing 4 is connected to the mounting base 8 via a threaded connection. The bottom surface of the upper housing 4 has an upper mounting cavity 03, and the acceleration detection core 01 is contained inside the upper mounting cavity 03. This structure integrates force detection and acceleration detection into the same housing, enabling synchronous acquisition of two signals. This eliminates the problems of large installation space occupation, asynchronous sampling, and time axis misalignment caused by multiple sensors. At the same time, stable pre-tightening is achieved through double threaded connection, which significantly improves the linearity of the sensor's initial range.

[0031] The force detection core 02 is composed of a force detection electrode sheet 11 and two force detection piezoelectric quartz 10. The force detection piezoelectric quartz 10 are respectively arranged on the upper and lower sides of the force detection electrode sheet 11. The force detection piezoelectric quartz 10 and the force detection electrode sheet 11 are both of annular structures and coaxially sleeved outside the lower end of the connecting column 121. The double-sided piezoelectric quartz structure can increase the charge output amplitude, ensure coaxial force application and uniform response. A force core insulation ring 13 is arranged between the force detection electrode sheet 11 and the connecting column 121. The inner peripheral surface of the force core insulation ring 13 is fitted with the outer peripheral surface of the connecting column 121, and the outer peripheral surface of the force core insulation ring 13 is fitted with the inner edges of the force detection electrode sheet 11 and the force detection piezoelectric quartz 10. The thickness d of the force core insulation ring 13, the thickness h of the force detection piezoelectric quartz 10, and the thickness H of the force detection electrode sheet 11 satisfy h + H < d < H + 2h. The insulation ring can achieve electrical isolation, avoid signal interference, and its size limitation makes it not participate in the force application, ensuring that the pre-tightening force acts entirely on the piezoelectric quartz and restricting the radial displacement of the components. The acceleration detection core 01 is composed of an acceleration insulation sheet 6, an acceleration electrode sheet 5, a piezoelectric ceramic 1, and a mass block 2. The cross-section of the acceleration core central column 7 is rectangular. The acceleration insulation sheet 6, the acceleration electrode sheet 5, the piezoelectric ceramic 1, and the mass block 2 are all arranged in two groups and symmetrically arranged on two opposite sides of the acceleration core central column 7. From the inside out, they are the acceleration insulation sheet 6, the acceleration electrode sheet 5, the piezoelectric ceramic 1, and the mass block 2. The double-sided symmetrical shear structure can improve the anti-transverse interference ability, make the inertial force act evenly and the output consistent, and the rectangular central column reduces the assembly deviation. One side of the mass block 2 facing away from the acceleration core central column 7 is an arc surface. An outer tightening ring 3 is sleeved outside the two mass blocks 2. The tightening ring 3 presses and fixes the mass block 2, the piezoelectric ceramic 1, the acceleration electrode sheet 5, and the acceleration insulation sheet 6 on the acceleration core central column 7. The tightening ring provides a continuous pre-tightening force to prevent the components from loosening, and the arc surface makes the holding force evenly distributed, extending the service life of the core.

[0032] Such as Figures 3 to 6As shown, the mounting base 8 has an annular groove 81 on its bottom surface, a central mounting boss 82 is provided at the center of the annular groove 81, a first internal thread 86 is provided on the inner side wall of the annular groove 81, and a first external thread 123 is provided on the outer periphery of the upper end of the lower housing 12. The lower housing 12 is screwed into the annular groove 81 through the first external thread 123 and the first internal thread 86. A lower mounting boss 122 is provided at the center of the bottom of the lower mounting cavity 04. The force detection core 02 is clamped between the central mounting boss 82 and the lower mounting boss 122. The threaded connection can accurately apply high preload, and the boss structure makes the force uniform, replacing the traditional welding preload and improving the structural reliability under large-range vibration environment. The mounting base 8 has a primary mounting boss 83 on its top surface, and a second external thread 84 on its outer periphery. The lower end of the inner wall of the upper mounting cavity 03 has a second internal thread 41. The upper housing 4 is fixed to the mounting base 8 through the engagement of the second external thread 84 and the second internal thread 41. A secondary mounting boss 85 is located at the center of the top surface of the primary mounting boss 83. The lower end face of the acceleration core center column 7 is in close contact with the upper surface of the secondary mounting boss 85. The threaded engagement improves the connection strength of the housing. The mounting base 8 is a regular hexagonal prism structure. Two output connectors 9 are provided on the outer periphery of the mounting base 8. The two output connectors 9 are respectively connected to the acceleration detection core 01 and the force detection core 02. The hexagonal prism structure facilitates on-site installation, and the dual output connectors enable independent output of two signals without interference, adapting to multi-channel acquisition equipment.

[0033] When the sensor is working, external forces and vibration loads act simultaneously on the sensor housing. Under the clamping preload of the mounting base 8 and the lower housing 12, the force detection core 02 is subjected to normal pressure by the force-measuring piezoelectric quartz 10. Based on the d11 piezoelectric effect, it generates a charge signal corresponding to the external force, which is output outward through the force-measuring electrode 11 and the output connector 9, completing the force parameter detection. The inertial force generated by vibration acts on the acceleration detection core 01. The mass block 2 causes the piezoelectric ceramic 1 to undergo shear deformation, outputting a corresponding charge signal based on the d15 / d26 piezoelectric effect. This signal is independently output through the acceleration electrode 5 and another output connector 9, completing the acceleration parameter detection. The two signals are synchronously acquired within the same structure without time delay, accurately reflecting the coupling relationship between force and acceleration, and maintaining stable linear output even under large-range vibration and impact conditions.

[0034] Example 2 This embodiment provides an assembly method for the above-mentioned piezoelectric force and acceleration composite sensor, including the following steps: S1. The force core insulating ring 13, the force measuring piezoelectric quartz 10, and the force measuring electrode 11 are sequentially sleeved on the connecting post 121 of the lower housing 12 to complete the assembly of the force detection core 02. The mounting base 8 is tightened by engaging the first internal thread 86 with the first external thread 123 of the lower housing 12, and a set preload is applied to the force detection core 02 so that the connecting post 121 passes upward through the central through hole of the mounting base 8. S2. The acceleration insulating sheet 6, acceleration electrode sheet 5, piezoelectric ceramic 1, and mass block 2 are symmetrically assembled on both sides of the acceleration core center column 7 in sequence, and fastened and fixed with fastening ring 3 to form acceleration detection core 01. Then, the assembled acceleration core center column 7 is connected to the upper end of the connecting column 121 by thread engagement and a pre-tightening force is applied to press the acceleration core center column 7 onto the upper surface of the secondary mounting boss 85 of the mounting base 8. S3. Tighten the upper housing 4 with the second internal thread 41 and the second external thread 84 of the mounting base 8 to complete the assembly of the upper housing 4 and the mounting base 8; S4. Weld and seal the joints between the mounting base 8 and the upper shell 4, and between the mounting base 8 and the lower shell 12, to form an integral sealed structure.

[0035] In step S2, an acceleration core mounting fixture 14 is used, such as... Figure 7-9 As shown, the accelerometer core installation fixture 14 includes a connecting plate 141. The bottom surface of the connecting plate 141 is provided with two stakes 142, which are spaced 180° apart. The cross-sectional shape of the stakes 142 is adapted to the shape of the space enclosed by the accelerometer core center column 7, the fastening ring 3, and the mass block 2. The stakes 142 can be inserted into the space to rotate the accelerometer core center column 7. The top surface of the connecting plate 141 is also provided with a hexagonal prism-shaped operating part 143.

[0036] As can be seen from the above embodiments, the advantages of the present invention are: Through an integrated structure, force detection and acceleration detection are combined into a single housing, enabling synchronous acquisition of two signals without time delay. This accurately reflects the coupling relationship between force and acceleration, eliminating the problems of large installation space occupation, asynchronous sampling, and time axis misalignment associated with multiple sensors. The use of double-threaded connections and a boss positioning structure allows for precise application of high preload, ensuring uniform force distribution. This replaces traditional welding preloading methods, improving structural reliability and linearity in the early stages of measurement under high-range vibration and impact conditions. The force detection core employs a double-sided piezoelectric quartz structure to enhance charge output amplitude, ensuring coaxial force distribution and uniform response. The acceleration detection core uses a double-sided symmetrical shear structure to improve resistance to lateral interference. Pre-tightening with fastening rings prevents component loosening and extends service life. Dual independent output connectors allow for independent, non-interfering output of two signals. The hexagonal prism mounting base facilitates on-site assembly. The overall structure is compact, with stable linear output and strong anti-interference capabilities, making it suitable for synchronous force and acceleration detection under high-range vibration and impact conditions.

[0037] The above description of the disclosed embodiments enables those skilled in the art to implement or use this patent. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this patent. Therefore, this patent is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A piezoelectric force and acceleration composite sensor, comprising a sensor housing, wherein an acceleration detection core (01) and a force detection core (02) are disposed within the sensor housing, characterized in that, The sensor housing includes a mounting base (8), and a lower housing (12) is threadedly mounted below the mounting base (8). The top surface of the lower housing (12) is provided with a lower mounting cavity (04). The force detection core (02) is clamped between the lower housing (12) and the mounting base (8). A connecting post (121) is provided at the center of the bottom surface inside the lower mounting cavity (04). The upper end of the connecting post (121) extends to the top of the mounting base (8). An acceleration core center post (7) is threadedly mounted on the upper end of the connecting post (121). The acceleration core center post (7) is pressed against the upper surface of the mounting base (8). The acceleration detection core (01) is mounted on the acceleration core center post (7). An upper housing (4) is also provided above the mounting base (8). The bottom surface of the upper housing (4) is provided with an upper mounting cavity (03). The acceleration detection core (01) is located in the upper mounting cavity (03).

2. The piezoelectric force and acceleration composite sensor according to claim 1, characterized in that, The force detection core (02) includes a force measuring electrode plate (11), and force measuring piezoelectric quartz (10) is provided on both the upper and lower sides of the force measuring electrode plate (11). The force measuring electrode plate (11) and the force measuring piezoelectric quartz (10) are both annular and surround the lower end of the connecting post (121).

3. The piezoelectric force and acceleration composite sensor according to claim 2, characterized in that, A core insulating ring (13) is also provided between the force-measuring electrode (11) and the connecting post (121). The inner circumferential surface of the core insulating ring (13) is in contact with the outer circumferential surface of the connecting post (121), and the outer circumferential surface of the core insulating ring (13) is in contact with the inner edge of the force-measuring electrode (11) and the force-measuring piezoelectric quartz (10). Let the thickness of the core insulating ring (13) be d, the thickness of the force-measuring piezoelectric quartz (10) be h, and the thickness of the force-measuring electrode (11) be H, satisfying h+H <d<H+2h。 4. The piezoelectric force and acceleration composite sensor according to claim 1, characterized in that, The acceleration detection core (01) includes an acceleration insulating sheet (6), an acceleration electrode sheet (5), a piezoelectric ceramic (1), and a mass block (2). The cross-section of the acceleration core center column (7) is rectangular. Two of each of the acceleration insulating sheet (6), acceleration electrode sheet (5), piezoelectric ceramic (1), and mass block (2) are provided and are respectively arranged on a set of phase back surfaces of the acceleration core center column (7). Along the direction away from the mass block (2), the acceleration insulating sheet (6), acceleration electrode sheet (5), piezoelectric ceramic (1), and mass block (2) are stacked in sequence.

5. The piezoelectric force and acceleration composite sensor according to claim 4, characterized in that, The side of the mass block (2) facing away from the acceleration core center column (7) is an arc-shaped surface. The outer periphery of the two mass blocks (2) is provided with a fastening ring (3). The fastening ring (3) presses the mass block (2), acceleration electrode plate (5) and acceleration insulating plate (6) onto the acceleration core center column (7).

6. The piezoelectric force and acceleration composite sensor according to claim 1, characterized in that, The bottom surface of the mounting base (8) is provided with an annular groove (81), the center of the annular groove (81) is provided with a central mounting boss (82), the inner side wall of the annular groove (81) is provided with a first internal thread (86), the upper edge of the lower housing (12) is provided with a first external thread (123), the lower housing (12) is screwed into the annular groove (81), the bottom surface of the lower mounting cavity (04) is provided with a lower mounting boss (122), the connecting column (121) is located at the center of the lower mounting boss (122), and the force detection core (02) is clamped between the central mounting boss (82) and the lower mounting boss (122).

7. The piezoelectric force and acceleration composite sensor according to claim 1, characterized in that, The top surface of the mounting base (8) is provided with a primary mounting boss (83), the outer periphery of the primary mounting boss (83) is provided with a second external thread (84), the lower end of the inner wall of the upper mounting cavity (03) is provided with a second internal thread (41), and the second external thread (84) and the second internal thread (41) are connected in a mating manner; the center of the top surface of the primary mounting boss (83) is provided with a secondary mounting boss (85), and the acceleration core center column (7) abuts against the upper surface of the secondary mounting boss (85).

8. The piezoelectric force and acceleration composite sensor according to claim 1, characterized in that, The mounting base (8) has a regular hexagonal prism structure. The outer circumference of the mounting base (8) is provided with two output connectors (9), which are connected to the acceleration detection core (01) and the force detection core (02) respectively.

9. A method for assembling a piezoelectric force and acceleration composite sensor as described in any one of claims 1-8, characterized in that, Includes the following steps: S1. Install the force detection core (02) on the lower housing (12), install the mounting base (8) above the lower housing (12) by thread and apply preload, and the connecting column (121) passes through the mounting base (8). S2. Install the acceleration detection core (01) on the acceleration core center column (7), and then thread the acceleration core center column (7) with the acceleration detection core (01) onto the upper end of the connecting column (121) and apply a preload. S3. Install the upper housing (4) onto the mounting base (8) by means of threads; S4. Weld and fix the joint between the mounting base (8) and the upper shell (4) and the joint between the mounting base (8) and the lower shell (12).

10. The assembly method according to claim 9, characterized in that, In step S2, an acceleration core installation fixture (14) is used. The acceleration core installation fixture (14) includes a connecting plate (141). The bottom surface of the connecting plate (141) is provided with two stakes (142). The two stakes (142) are set at a distance of 180°. The cross-sectional shape of the stakes (142) is adapted to the shape of the space enclosed by the acceleration core center column (7), the fastening ring (3) and the mass block (2). The stakes (142) can be inserted into the space to rotate the acceleration core center column (7). The top surface of the connecting plate (141) is also provided with a hexagonal prism-shaped operating part (143).

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