A piezoelectric quartz sensor with automatic sensitivity compensation and a measuring method

Abstract

This invention provides a piezoelectric quartz sensor with automatic sensitivity compensation and a measurement method, relating to the field of sensor technology. The piezoelectric quartz sensor includes a sensor housing, a quartz sensing element, a pre-tightening unit, a signal processing unit, and a quartz ring unit. The quartz ring unit is fitted onto the pre-tightening unit, which applies a pre-tightening force to the quartz ring unit. The pre-tightening forces applied to the quartz ring unit and the quartz sensing element are equal. When an external force is applied, the quartz sensing element generates a first electrical signal based on the sum of the pre-tightening force and the external force, and the quartz ring unit generates a second electrical signal based on the difference between the pre-tightening force and the external force. Both the quartz ring unit and the quartz sensing element are electrically connected to the signal processing unit. The signal processing unit performs a differential operation on the first and second electrical signals to obtain an output signal. By canceling the pre-tightening force through differential operation, the final output signal is unaffected by changes in the pre-tightening force, automatically compensating for sensitivity changes caused by variations in the pre-tightening force.

Description

Technical Field

[0001] This invention relates to the field of sensor technology, specifically to a piezoelectric quartz sensor with automatic sensitivity compensation and a measurement method thereof. Background Technology

[0002] Piezoelectric sensors, which use quartz crystals as sensing elements, are widely used in various fields to measure dynamic forces, pressures, and accelerations. When an external load is applied to the sensor's transmission structure, the transmission structure transmits the force to the internal quartz crystal. The quartz crystal generates an electric charge signal proportional to the load due to the force, thereby realizing the conversion of physical quantities into electrical signals.

[0003] However, under actual working conditions, after long-term temperature cycling, alternating stress and impact loads, the transmission structure will inevitably experience material fatigue and micro-creep, which will cause changes in the preload applied to the quartz crystal, and thus change the sensitivity of the sensor.

[0004] To correct sensitivity and restore sensor measurement accuracy, the current common practice is to recalibrate and re-verify the sensor. However, for many specific applications, such as structural health monitoring deep underground, long-term on-orbit spacecraft, condition monitoring sealed inside engines, or remote monitoring stations in extremely harsh environments, sensors cannot be disassembled for recalibration once installed. This means that after long-term operation, sensor accuracy cannot be guaranteed, and data reliability decreases. Summary of the Invention

[0005] The purpose of this invention is to provide a piezoelectric quartz sensor with automatic sensitivity compensation and a measurement method. The technical problem to be solved is to address the issue of sensitivity changes over long-term use of the sensor without relying on recalibration.

[0006] This invention is achieved through the following technical solution:

[0007] The first aspect provides a piezoelectric quartz sensor with automatic sensitivity compensation, including a sensor housing, a quartz sensing unit disposed within the sensor housing, a pre-tightening unit for applying a pre-tightening force to the quartz sensing unit, and a signal processing unit. The sensor is characterized in that it further includes a quartz ring unit, which is sleeved on the pre-tightening unit. The pre-tightening unit applies a pre-tightening force to the quartz ring unit, and the values ​​of the pre-tightening forces applied to the quartz ring unit and the quartz sensing unit are equal.

[0008] When an external force is applied, the quartz sensing unit generates a first electrical signal based on the sum of the preload and the external force, and the quartz ring unit generates a second electrical signal based on the difference between the preload and the external force.

[0009] Both the quartz ring unit and the quartz sensing unit are electrically connected to the signal processing unit. The signal processing unit is used to receive the first electrical signal output by the quartz sensing unit and the second electrical signal output by the quartz ring unit, and to perform differential operation on the first electrical signal and the second electrical signal to obtain the output signal.

[0010] In this invention, the quartz ring unit and the quartz sensing unit are subjected to equal preload, and a first electrical signal is generated based on the sum of the preload and the external force, and a second electrical signal is generated based on their difference. The signal processing unit cancels out the preload through differential operation, so that the final output signal is only related to the external force and is not affected by changes in the preload. This invention automatically compensates for sensitivity changes caused by changes in preload by using the aforementioned quartz ring unit and quartz sensing unit to monitor changes in preload and external force in real time, and by using the differential operation mechanism of the signal processing unit. Regardless of how the preload changes, the final output signal only reflects the magnitude of the external force, eliminating the need for recalibration of the sensor, improving the ease of use and reliability of the sensor, and reducing operating costs and maintenance workload.

[0011] Moreover, because the charge generated by the output signal is twice that of the normal force, the sensitivity is doubled.

[0012] Furthermore, the sensor housing has an opening with an elastic thin plate attached thereto, and the elastic thin plate is connected to the sensor housing; the two end faces of the pre-tightening unit are respectively used to fit the elastic thin plate and the quartz sensing unit.

[0013] The elastic thin plate is used to directly bear external forces, which are transmitted to the quartz sensing unit through the pre-tightening unit.

[0014] Furthermore, the sensor housing has an opening at one end, which is provided with a connecting plate for connecting the elastic thin plate and an abutting plate for abutting the pre-tightening unit; the connecting plate, the abutting plate and the sensor housing together form a receiving cavity for accommodating the quartz ring unit.

[0015] The pre-tightening unit abuts against the abutting plate. When transmitting external force, the pre-tightening unit moves toward the quartz sensing unit, while at the same time the pre-tightening unit moves away from the quartz ring unit. When the pre-tightening unit moves away from the quartz ring unit, the force on the quartz ring unit decreases, and the force on the quartz sensing unit increases, and the decrease in force and the increase in force are the same.

[0016] Furthermore, the quartz ring unit includes a quartz ring, a first conductive layer, and a first insulating layer. One end face of the quartz ring is in contact with the pre-tightening unit, and the other end face is in contact with the first conductive layer. The two end faces of the first insulating layer are in contact with the first conductive layer and the connecting plate, respectively.

[0017] The piezoelectric effect of quartz crystals is used to measure physical quantities. A quartz ring generates an electrical signal when subjected to force, converting the physical quantity into an electrical signal for measurement. A first conductive layer is coated on the surface of the quartz ring to conduct the second electrical signal generated by the ring. A first insulating layer isolates the first conductive layer from the connecting plate, preventing leakage and interference of the second electrical signal. Similarly, the quartz sensing unit may also include a quartz pillar, a first conductive layer, and a first insulating layer. These layers are positioned between the quartz pillar and the sensor housing to conduct the first electrical signal and prevent leakage and interference.

[0018] Furthermore, the signal processing unit includes a differential amplifier, which determines the output signal using the following formula:

[0019] ,

[0020] in, Indicates the output signal; Indicates the first electrical signal; Indicates the second electrical signal; Indicates preload; It indicates external force.

[0021] During differential operations, the preload is offset, eliminating the influence of preload changes on the output results and ensuring sensitivity; the charge generated by the final output signal is twice that of the normal force, thus doubling the sensitivity.

[0022] A second aspect provides a measurement method employing any one of the piezoelectric quartz sensors described in the previous embodiment; the measurement method includes the following steps:

[0023] The resultant force of the preload and the external force is monitored by a quartz sensing element, and a first electrical signal is generated based on the resultant force.

[0024] The difference between the preload and the external force is monitored by a quartz ring unit, and a second electrical signal is generated based on the difference between the preload and the external force.

[0025] The signal processing unit performs a differential operation on the first electrical signal and the second electrical signal to obtain the output signal of the feedback external force.

[0026] The effect of preload on the output signal is offset by differential operation.

[0027] Furthermore, the preload applied by the preload unit to the quartz ring unit and the quartz sensing unit is equal in value.

[0028] Furthermore, the output signal is determined using the following formula:

[0029] ,

[0030] in, Indicates the output signal; Indicates the first electrical signal; Indicates the second electrical signal; Indicates preload; It indicates external force.

[0031] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0032] In this invention, the quartz ring unit and the quartz sensing unit are subjected to equal preload, and a first electrical signal is generated based on the sum of the preload and the external force, and a second electrical signal is generated based on their difference. The signal processing unit cancels out the preload through differential operation, so that the final output signal is only related to the external force and is not affected by changes in the preload. This invention automatically compensates for sensitivity changes caused by changes in preload by using the aforementioned quartz ring unit and quartz sensing unit to monitor changes in preload and external force in real time, and by using the differential operation mechanism of the signal processing unit. Regardless of how the preload changes, the final output signal only reflects the magnitude of the external force, eliminating the need for recalibration of the sensor, improving the ease of use and reliability of the sensor, and reducing operating costs and maintenance workload.

[0033] Moreover, because the charge generated by the output signal is twice that of the normal force, the sensitivity is doubled. Attached Figure Description

[0034] To more clearly illustrate the technical solutions of the exemplary embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly described below. It should be understood that the following drawings only show some embodiments of the present invention and should not be considered as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort. In the drawings:

[0035] Figure 1 This is a cross-sectional view of a piezoelectric quartz sensor.

[0036] Figure 2 This is a force diagram of the quartz sensitive element and the quartz ring element.

[0037] The attached diagram shows the markings and corresponding component names:

[0038] 1. Sensor housing; 11. Connecting plate; 12. Abutment plate; 13. Receiving cavity; 2. Pre-tightening unit; 3. Quartz sensing unit; 31. Quartz pillar; 32. Second conductive layer; 33. Second insulating layer; 4. Quartz ring unit; 41. First insulating layer; 42. First conductive layer; 43. Quartz ring; 5. Elastic thin plate. Detailed Implementation

[0039] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the embodiments and accompanying drawings. The illustrative embodiments and descriptions of this invention are only for explaining this invention and are not intended to limit this invention.

[0040] First embodiment:

[0041] A piezoelectric quartz sensor with automatic sensitivity compensation includes a sensor housing 1, a quartz sensing unit 3 disposed within the sensor housing 1, a pre-tightening unit 2 for applying a pre-tightening force to the quartz sensing unit 3, and a signal processing unit. The sensor is characterized by further including a quartz ring unit 4, which is sleeved on the pre-tightening unit 2. The pre-tightening unit 2 applies a pre-tightening force to the quartz ring unit 4, and the values ​​of the pre-tightening forces applied to the quartz ring unit 4 and the quartz sensing unit 3 are equal.

[0042] When an external force is applied, the quartz sensing unit 3 generates a first electrical signal based on the sum of the preload and the external force, and the quartz ring unit 4 generates a second electrical signal based on the difference between the preload and the external force.

[0043] The quartz ring unit 4 and the quartz sensing unit 3 are both electrically connected to the signal processing unit. The signal processing unit is used to receive the first electrical signal output by the quartz sensing unit 3 and the second electrical signal output by the quartz ring unit 4, and to perform differential operation on the first electrical signal and the second electrical signal to obtain the output signal.

[0044] In this invention, the quartz ring unit 4 and the quartz sensing unit 3 are subjected to equal preload, and a first electrical signal is generated based on the sum of the preload and the external force, and a second electrical signal is generated based on their difference. The signal processing unit cancels out the preload through differential operation, so that the final output signal is only related to the external force and is not affected by changes in the preload. This invention automatically compensates for sensitivity changes caused by changes in preload by using the quartz ring unit 4 and the quartz sensing unit 3 to monitor changes in preload and external force in real time, and by using the differential operation mechanism of the signal processing unit. No matter how the preload changes, the final output signal only reflects the magnitude of the external force, eliminating the need for recalibration of the sensor, improving the ease of use and reliability of the sensor, and reducing operating costs and maintenance workload.

[0045] Moreover, because the charge generated by the output signal is twice that of the normal force, the sensitivity is doubled.

[0046] In a specific embodiment, the signal processing unit includes a differential amplifier, which determines the output signal using the following formula:

[0047] ,

[0048] in, Indicates the output signal; Indicates the first electrical signal; Indicates the second electrical signal; Indicates preload; It indicates external force.

[0049] During differential operations, the preload is offset, eliminating the influence of preload changes on the output results and ensuring sensitivity; the charge generated by the final output signal is twice that of the normal force, thus doubling the sensitivity.

[0050] In a specific test scenario, a standard force is applied to the sensor. When the sensor is functioning normally and is not under load, the force on the quartz pillar 31 is a preload. The force on quartz ring 43 is also the preload force. At this time, an external force is applied to the sensor. The increased force on quartz pillar 31 becomes The force on quartz ring 43 decreases and becomes Therefore, the quartz pillar 31 and the quartz ring 43 are differentiated into... The generated charge is twice that of normal force, and the sensor sensitivity is doubled.

[0051] When the sensor structure experiences preload due to temperature, mechanical creep, stress changes, etc. Become At that time, the preload force on quartz column 31 becomes The preload force on quartz ring 43 also becomes At this point, the same external force is still applied to the sensor. The increased force on quartz pillar 31 becomes The force on quartz ring 43 decreases and becomes Therefore, the quartz pillar 31 and the quartz ring 43 are differentiated into... The results are the same as before, and the measurement results remain unchanged.

[0052] Second embodiment:

[0053] Based on the first embodiment, the sensor housing 1 is provided with an opening, and an elastic thin plate 5 is provided in the opening. The elastic thin plate 5 is connected to the sensor housing 1. The two end faces of the pre-tightening unit 2 are respectively used to fit the elastic thin plate 5 and the quartz sensing unit 3.

[0054] The elastic thin plate 5 is used to directly bear external forces, which are transmitted to the quartz sensitive unit 3 through the pre-tightening unit 2.

[0055] In a specific embodiment, the sensor housing 1 has an opening at one end, which is provided with a connecting plate 11 for connecting the elastic thin plate 5 and an abutting plate 12 for abutting the pre-tightening unit 2; the connecting plate 11, the abutting plate 12 and the sensor housing 1 together form a receiving cavity 13 for accommodating the quartz ring unit 4. The elastic thin plate 5 and the connecting plate 11 can be sealed by gold soldering, laser welding or resistance welding.

[0056] The pre-tightening unit 2 abuts against the abutting plate 12. When transmitting external force, the pre-tightening unit 2 moves toward the quartz sensitive unit 3, while at the same time the pre-tightening unit 2 moves away from the quartz ring unit 4. When the pre-tightening unit 2 moves away from the quartz ring unit 4, the force on the quartz ring unit 4 decreases, and the force on the quartz sensitive unit 3 increases, and the decrease in force and the increase in force are the same.

[0057] Third embodiment:

[0058] Based on the second embodiment, the quartz ring unit 4 includes a quartz ring 43, a first conductive layer 42 and a first insulating layer 41. One end face of the quartz ring 43 is in contact with the pre-tightening unit 2, and the other end face is in contact with the first conductive layer 42. The two end faces of the first insulating layer 41 are in contact with the first conductive layer 42 and the connecting plate 11, respectively.

[0059] The piezoelectric effect of quartz crystal is used to measure physical quantities. A quartz ring 43 generates an electrical signal when subjected to force, converting the physical quantity into an electrical signal for measurement. A first conductive layer 42 is coated on the surface of the quartz ring 43 to conduct the second electrical signal generated by the quartz ring 43. A first insulating layer 41 isolates the first conductive layer 42 from the connecting plate 11, preventing leakage and interference of the second electrical signal. Similarly, the quartz sensing unit 3 may also include a quartz pillar 31, a second conductive layer 32, and a second insulating layer 33. The second conductive layer 32 and the second insulating layer 33 are disposed between the quartz pillar 31 and the sensor housing 1 to conduct the first electrical signal and prevent leakage and interference of the first electrical signal. The signal processing unit can be connected to the quartz ring unit 4 and the quartz sensing unit 3 through the first conductive layer 42 and the second conductive layer 32.

[0060] Fourth embodiment:

[0061] A measurement method employing any one of the piezoelectric quartz sensors described above; the measurement method includes the following steps:

[0062] The resultant force of the preload and the external force is monitored by the quartz sensing element 3, and a first electrical signal is generated based on the resultant force.

[0063] The difference between the preload and the external force is monitored by the quartz ring unit 4, and a second electrical signal is generated based on the difference between the preload and the external force.

[0064] The signal processing unit performs a differential operation on the first electrical signal and the second electrical signal to obtain the output signal of the feedback external force.

[0065] The effect of preload on the output signal is offset by differential operation.

[0066] In a specific embodiment, the pre-tightening force applied by the pre-tightening unit 2 to the quartz ring unit 4 and the quartz sensing unit 3 is equal.

[0067] In a specific embodiment, the output signal is determined using the following formula:

[0068] ,

[0069] in, Indicates the output signal; Indicates the first electrical signal; Indicates the second electrical signal; Indicates preload; It indicates external force.

[0070] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A piezoelectric quartz sensor with automatic sensitivity compensation, comprising a sensor housing (1), a quartz sensing element (3) disposed within the sensor housing (1), a pre-tightening unit (2) for applying a pre-tightening force to the quartz sensing element (3), and a signal processing unit, characterized in that, It also includes a quartz ring unit (4), which is sleeved on the pre-tightening unit (2). The pre-tightening unit (2) applies a pre-tightening force to the quartz ring unit (4). The values ​​of the pre-tightening forces applied to the quartz ring unit (4) and the quartz sensing unit (3) are equal. When an external force is applied, the quartz sensing unit (3) generates a first electrical signal based on the sum of the preload and the external force, and the quartz ring unit (4) generates a second electrical signal based on the difference between the preload and the external force. The quartz ring unit (4) and the quartz sensing unit (3) are both electrically connected to the signal processing unit. The signal processing unit is used to receive the first electrical signal output by the quartz sensing unit (3) and the second electrical signal output by the quartz ring unit (4), and to perform differential operation on the first electrical signal and the second electrical signal to obtain the output signal. The sensor housing (1) has an opening, and an elastic thin plate (5) is provided in the opening. The elastic thin plate (5) is connected to the sensor housing (1). The two end faces of the pre-tightening unit (2) are respectively used to fit the elastic thin plate (5) and the quartz sensing unit (3). The sensor housing (1) has an opening at one end, which is provided with a connecting plate (11) for connecting the elastic thin plate (5) and an abutting plate (12) for abutting the pre-tightening unit (2); the connecting plate (11), the abutting plate (12) and the sensor housing (1) together form a receiving cavity (13) for receiving the quartz ring unit (4).

2. The piezoelectric quartz sensor according to claim 1, characterized in that, The quartz ring unit (4) includes a quartz ring (43), a first conductive layer (42) and a first insulating layer (41). One end face of the quartz ring (43) is in contact with the pre-tightening unit (2), and the other end face is in contact with the first conductive layer (42). The two end faces of the first insulating layer (41) are in contact with the first conductive layer (42) and the connecting plate (11) respectively.

3. The piezoelectric quartz sensor according to claim 1, characterized in that, The signal processing unit includes a differential amplifier, which determines the output signal using the following formula: ， in, Indicates the output signal; Indicates the first electrical signal; Indicates the second electrical signal; Indicates preload; It indicates external force.

4. A measurement method, characterized in that, The measurement method employs the piezoelectric quartz sensor as described in any one of claims 1 to 3; the measurement method includes the following steps: The resultant force of the preload and the external force is monitored by the quartz sensing element (3), and a first electrical signal is generated based on the resultant force; The difference between the preload and the external force is monitored by the quartz ring unit (4), and a second electrical signal is generated based on the difference between the preload and the external force. The signal processing unit performs a differential operation on the first electrical signal and the second electrical signal to obtain the output signal of the feedback external force.

5. The measurement method according to claim 4, characterized in that, The pre-tightening force applied by the pre-tightening unit to the quartz ring unit (4) and the quartz sensing unit (3) is equal.

6. The measurement method according to claim 5, characterized in that, The output signal is determined using the following formula: ， in, Indicates the output signal; Indicates the first electrical signal; Indicates the second electrical signal; Indicates preload; It indicates external force.

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