Sensor

Abstract

A sensing element on a circuit board is used for sensing the physical quantity of a measured position and converting the physical quantity into an electric signal, a connecting cable penetrates through a central opening of a pressing sleeve to be connected with the circuit board and is transmitted to a rear-stage acquisition instrument through an electric connector, and the circuit board and the pressing sleeve are both arranged in an inner cavity of a sensor shell. The first end of the circuit board is inserted into the bottom of the sensor shell, the pressing sleeve can be connected with the inner wall of the sensor shell in an attached mode through the outer surface of the installation part, the end, away from the installation part, of the fixing part abuts against the second end of the circuit board, the circuit board can be axially pressed, and the outer diameter of the fixing part is smaller than that of the installation part, that is, the pressing sleeve can press the circuit board. A gap is reserved between the outer surface of the fixing part and the inner wall of the sensor shell, and when pouring sealant is poured into the inner cavity of the sensor shell, the filling area of the pouring sealant can be increased, so that the holding force between the pressing sleeve and the inner wall of the sensor shell is increased, the fixing effect of the circuit board is improved, and the signal monitoring sensitivity of the sensor is ensured.

Description

[0001] This disclosure is a divisional application of the patent application filed on March 12, 2020, with application number 2020101707960 and invention title "A Sensor". Technical Field

[0002] This invention relates to the field of monitoring equipment technology, and in particular to a sensor. Background Technology

[0003] As a monitoring device, sensors are widely used in fields such as machinery, ships, and rail transportation. Inside the sensor housing, there is a circuit board. The sensitive elements on the circuit board sense physical quantities such as vibration, impact, and temperature signals at the measured location, convert them into electrical signals, and then transmit the signals through connecting cables.

[0004] In existing technologies, the circuit board is typically inserted into the sensor housing and secured by compression. Encapsulating compound is then poured into the sensor housing to achieve insulation and shock resistance. However, this method cannot control the accurate positioning of the circuit board, and it is prone to loosening under long-term vibration and impact, leading to a decrease in the sensor's signal monitoring sensitivity. Summary of the Invention

[0005] To address the aforementioned technical problems, this invention provides a sensor that enables accurate positioning of the circuit board inside the sensor, ensuring the circuit board's fixation effect and improving the sensor's signal monitoring sensitivity.

[0006] The sensor provided by this invention includes a sensor probe, a connecting cable, and an electrical connector;

[0007] The sensor probe includes a sensor housing, the inner cavity of which is provided with a circuit board and a pressure sleeve. The first end of the circuit board is inserted into the bottom of the sensor housing. The pressure sleeve includes a pressure sleeve body with a central opening. The pressure sleeve body includes a fixing part and a mounting part connected to the fixing part. The outer diameter of the fixing part is smaller than the outer diameter of the mounting part. The end of the fixing part away from the mounting part abuts against the second end of the circuit board. The outer surface of the mounting part is in close contact with the inner wall of the sensor housing. A gap is provided between the outer surface of the fixing part and the inner wall of the sensor housing. The inner cavity of the sensor housing is filled with potting compound.

[0008] One end of the connecting cable passes through the central opening of the pressure sleeve and connects to the circuit board, while the other end of the connecting cable connects to the electrical connector.

[0009] Preferably, the sensor probe further includes a pressure cap, the first end face of the bottom end of the pressure cap abuts against the end of the mounting part away from the fixing part, and a sealing ring is provided between the first end face of the bottom end of the pressure cap and the end of the mounting part away from the fixing part. The outer surface of the bottom end of the pressure cap is engaged with the inner wall of the sensor housing to axially press the sealing ring. The top end face of the pressure cap has an opening for the connecting cable to pass through, and the inner surface of the bottom end of the pressure cap has a tapered groove for installing the sealing ring.

[0010] Preferably, the sensor probe further includes a pressure cap and a sealing sleeve located inside the pressure cap. A flexible tube is sleeved on the outside of the connecting cable. The inner wall of the pressure cap is connected to the outer wall of the sensor body. The pressure cap is engaged with the second end face of the bottom end of the pressure cap to axially clamp the sealing sleeve. The inner wall of the sealing sleeve and the outer surface of the top end of the pressure cap form a receiving cavity for accommodating the flexible tube. The inner wall of the sealing sleeve is provided with a plurality of first protrusions that cooperate with the outer wall of the flexible tube. The outer surface of the top end of the pressure cap is provided with a plurality of second protrusions that cooperate with the inner wall of the flexible tube.

[0011] Preferably, the first end of the circuit board is provided with a stepped plate for soldering the pins of the temperature sensing element, and the thickness of the stepped plate is less than the thickness of the circuit board itself.

[0012] Preferably, the outer periphery of the bottom of the sensor housing is provided with a first outer conical surface for signal transmission, the inner wall of the bottom of the sensor housing is also provided with an inner conical surface, and the outer periphery of the first end of the circuit board is provided with a second outer conical surface that mates with the inner conical surface.

[0013] Preferably, a sensitive element and a signal conditioning circuit are mounted on the side of the circuit board. The sensitive element is used to sense the physical quantity of vibration and impact at the measured position and convert it into a voltage signal. The signal conditioning circuit is used to convert the voltage signal output by the sensitive element into a current signal.

[0014] Preferably, the signal conditioning circuit includes an operational amplifier module, a voltage-to-current conversion module, and an output current compensation module;

[0015] The input terminal of the operational amplifier module is connected to the output terminal of the sensitive element, and is used to adjust the voltage level signal output by the sensitive element to a preset level;

[0016] The input terminal of the voltage-to-current conversion module is connected to the output terminal of the operational amplifier module, and the output terminal of the voltage-to-current conversion module is connected to the input terminal of the subsequent detection system, for converting the voltage signal output by the operational amplifier module into a current signal;

[0017] The input terminal of the output current compensation module is connected to a first reference voltage, and the output terminal of the output current compensation module is connected to the inverting input terminal of the operational amplifier in the voltage-current conversion module. The output current compensation module generates a corresponding compensation current based on the first reference voltage and inputs it into the voltage-current conversion module to compensate its output current signal.

[0018] Preferably, the output current compensation module includes a first resistor, with a first end of the first resistor serving as the input terminal of the output current compensation module and a second end of the first resistor serving as the output terminal of the output current compensation module.

[0019] Preferably, the voltage-to-current conversion module includes a second resistor, a third resistor, a fourth resistor, a first operational amplifier, and an NMOS transistor;

[0020] The first end of the second resistor serves as the input terminal of the voltage-to-current conversion module. The second end of the second resistor is connected to the non-inverting input terminal of the first operational amplifier. The inverting input terminal of the first operational amplifier is connected to the second end of the first resistor, the first end of the third resistor, and the source of the NMOS transistor. The second end of the third resistor is connected to ground. The output terminal of the first operational amplifier is connected to the first end of the fourth resistor. The second end of the fourth resistor is connected to the gate of the NMOS transistor. The drain of the NMOS transistor serves as the output terminal of the voltage-to-current conversion module.

[0021] Preferably, the operational amplifier module includes a fifth resistor, a sixth resistor, a seventh resistor, an eighth resistor, and a second operational amplifier;

[0022] The first end of the fifth resistor is connected to ground, the second end of the fifth resistor is connected to the non-inverting input of the second operational amplifier and the first end of the sixth resistor, the second end of the sixth resistor is connected to the second reference voltage, the first end of the seventh resistor serves as the input of the operational amplifier module, the second end of the seventh resistor is connected to the inverting input of the second operational amplifier and the first end of the eighth resistor, the second end of the eighth resistor is connected to the output of the second operational amplifier, and their common end serves as the output of the operational amplifier module.

[0023] The sensor provided by this invention senses the physical quantity at the measured location through a sensitive element mounted on a circuit board, converts it into an electrical signal, and then connects the circuit board via a connecting cable that passes through the central opening of a pressure sleeve. The generated electrical signal is transmitted to a subsequent data acquisition instrument via an electrical connector. Both the circuit board and the pressure sleeve are located within the inner cavity of the sensor housing, with the first end of the circuit board inserted into the bottom of the sensor housing. The pressure sleeve can be fitted against the inner wall of the sensor housing through the outer surface of the mounting part. The fixing part, located away from the mounting part, abuts against the second end of the circuit board, axially pressing the circuit board. The outer diameter of the fixing part is smaller than that of the mounting part, meaning there is a gap between the outer surface of the fixing part and the inner wall of the sensor housing. When potting compound is poured into the inner cavity of the sensor housing, the filling area of ​​the potting compound can be increased to increase the holding force between the pressure sleeve and the inner wall of the sensor housing, thereby improving the fixation effect of the circuit board. Therefore, compared with the prior art, the sensor provided by this invention can ensure the fixation effect of the internal circuit board and improve the signal monitoring sensitivity of the sensor. Attached Figure Description

[0024] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0025] Figure 1 This is a schematic diagram of the structure of a sensor provided in an embodiment of the present invention;

[0026] Figure 2 This is a schematic diagram of the structure of a sensor probe provided in an embodiment of the present invention;

[0027] Figure 3 This is a schematic diagram of another sensor probe provided in an embodiment of the present invention;

[0028] Figure 4 This is a schematic diagram of a pressure sleeve provided in an embodiment of the present invention;

[0029] Figure 5 A three-dimensional schematic diagram of a circuit board provided in an embodiment of the present invention;

[0030] Figure 6 A front view schematic diagram of a circuit board provided in an embodiment of the present invention;

[0031] Figure 7 A rear view schematic diagram of a circuit board provided in an embodiment of the present invention;

[0032] Figure 8A left-side view of a circuit board provided in an embodiment of the present invention;

[0033] Figure 9 This is a schematic diagram of the structure of a sensor housing provided in an embodiment of the present invention;

[0034] Figure 10 This is a schematic diagram of a signal conditioning circuit provided in an embodiment of the present invention;

[0035] Figure 11 This is a schematic diagram of another signal conditioning circuit provided in an embodiment of the present invention. Detailed Implementation

[0036] To enable those skilled in the art to better understand the technical solutions in this application, the technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments.

[0037] It should be noted that when a component is referred to as being "fixed to" or "set on" another component, it can be directly on or indirectly set on the other component; when a component is referred to as being "connected to" another component, it can be directly connected to or indirectly connected to the other component.

[0038] It should be understood that the terms "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0039] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, "multiple" or "several" means two or more, unless otherwise explicitly specified.

[0040] It should be noted that the structures, proportions, sizes, etc., shown in the accompanying drawings of this specification are only used to complement the content disclosed in the specification for those skilled in the art to understand and read, and are not intended to limit the conditions under which this application can be implemented. Therefore, they have no substantial technical significance. Any modifications to the structure, changes in the proportions, or adjustments to the size, without affecting the effects and purposes that this application can produce, should still fall within the scope of the technical content disclosed in this application.

[0041] As described in the background section, sensors typically employ a method of inserting a circuit board into a sensor housing, securing the board with a clamping mechanism, and then filling the housing with potting compound to achieve insulation and shock resistance. However, this fixing method cannot control the accurate positioning of the circuit board, and under long-term vibration and impact conditions, the circuit board is prone to loosening, leading to a decrease in the sensor's vibration and impact sensitivity.

[0042] In view of this, embodiments of the present invention provide a sensor. Please refer to... Figures 1 to 9 The sensor includes a sensor probe 101, a connecting cable 6, and an electrical connector 102. The sensor probe 101 includes a sensor housing 1. The inner cavity of the sensor housing 1 is provided with a circuit board 2 and a pressure sleeve 3. The first end of the circuit board 2 is inserted into the bottom of the sensor housing 1. The pressure sleeve 3 includes a pressure sleeve body with a central opening. The pressure sleeve body includes a fixing part 31 and a mounting part 32 connected to the fixing part 31. The outer diameter of the fixing part 31 is smaller than the outer diameter of the mounting part 32. The end of the fixing part 31 away from the mounting part 32 abuts against the second end of the circuit board 2. The outer surface of the mounting part 32 is in close contact with the inner wall of the sensor housing 1. A gap is provided between the outer surface of the fixing part 31 and the inner wall of the sensor housing 1. The inner cavity of the sensor housing 1 is filled with potting compound. One end of the connecting cable 6 passes through the central opening of the pressure sleeve 3 and connects to the circuit board 2. The other end of the connecting cable 6 is connected to the electrical connector 102.

[0043] In this embodiment of the invention, the physical quantity at the measured location is sensed by a sensitive element mounted on the circuit board 2 and converted into an electrical signal. A connecting cable 6 passes through the central opening of the pressure sleeve 3 and connects to the circuit board 2. The generated electrical signal is transmitted to the subsequent data acquisition instrument via an electrical connector 102. Both the circuit board 2 and the pressure sleeve 3 are located within the inner cavity of the sensor housing 1. The first end of the circuit board 2 is inserted into the bottom of the sensor housing 1. The pressure sleeve 3 can be fitted against the inner wall of the sensor housing 1 via the outer surface of the mounting part 32. The fixing part 31, with one end away from the mounting part 32, abuts against the second end of the circuit board 2, axially pressing the circuit board 2. The outer diameter of the fixing part 31 is smaller than the outer diameter of the mounting part 32, meaning there is a gap between the outer surface of the fixing part 31 and the inner wall of the sensor housing 1. When potting compound is poured into the inner cavity of the sensor housing 1, the filling area of ​​the potting compound can be increased to increase the holding force between the pressure sleeve 3 and the inner wall of the sensor housing 1, thereby improving the fixing effect of the circuit board 2. Therefore, compared with the prior art, the sensor provided in this embodiment of the invention can ensure the fixing effect of the internal circuit board and improve the signal monitoring sensitivity of the sensor.

[0044] In order to clamp the connecting cable of the circuit board while fixing the circuit board, in a specific embodiment based on the above embodiments, the sensor probe further includes a cover 4. The first end face of the bottom end of the cover 4 abuts against the end of the mounting part 32 away from the fixing part 31, and a sealing ring 5 is provided between the first end face of the bottom end of the cover 4 and the end of the mounting part 32 away from the fixing part 31. The outer surface of the bottom end of the cover 4 is connected to the inner wall of the sensor housing 1 to axially press the sealing ring 5. The end face of the top end of the cover 4 is provided with an opening for the connecting cable 6 to pass through, and the inner surface of the bottom end of the cover 4 is provided with a tapered groove for installing the sealing ring 5.

[0045] In this embodiment, the top end face of the pressure cover 4 is provided with an opening, through which the connecting cable 6 can pass to connect with the internal circuit board 2. A sealing ring 5 is provided between the first end face of the bottom end of the pressure cover 4 and the end of the mounting part 32 away from the fixing part 31. By tightly fitting the outer surface of the bottom end of the pressure cover 4 with the inner wall of the sensor housing 1, the sealing ring 5 can be axially pressed, thereby clamping the cable 6 to achieve the effect of waterproofing and dustproofing.

[0046] In this embodiment, the sealing ring 5 can be an O-ring, and the inner surface of the bottom end of the pressure cap 4 is provided with a conical groove, in which the O-ring can be installed. The volume of the sealing ring 5 is slightly larger than the volume of the conical groove, allowing for further compression of the sealing ring 5 during installation to axially press the connecting cable 6, thereby improving the waterproof and dustproof effect.

[0047] In specific implementation, the maximum outer diameter of the mounting part 32 can be interference-fitted with the inner wall of the sensor housing 1, and the outer surface of the bottom end of the pressure cover 4 can also be interference-fitted with the inner wall of the sensor housing 1 to ensure the reliability of the installation. At the same time, laser welding can be used to weld the joint between the pressure cover 4 and the sensor housing 1.

[0048] To further improve the waterproof and dustproof performance of the connecting cable, based on the above embodiments, in a specific embodiment, the sensor probe further includes a pressure cap 7 and a sealing sleeve 8 located inside the pressure cap 7. A flexible tube 9 is sleeved on the outside of the connecting cable 6. The inner wall of the pressure cap 7 is connected to the outer wall of the sensor housing 1. The pressure cap 7 is engaged with the second end face of the bottom end of the pressure cap 4 to axially clamp the sealing sleeve 8. The inner wall of the sealing sleeve 8 and the outer surface of the top end of the pressure cap 4 form a receiving cavity for accommodating the flexible tube 9. The inner wall of the sealing sleeve 8 is provided with a plurality of first protrusions that cooperate with the outer wall of the flexible tube 9. The outer surface of the top end of the pressure cap 4 is provided with a plurality of second protrusions that cooperate with the inner wall of the flexible tube 9.

[0049] In this embodiment, since the flexible hose has good flexibility and fatigue resistance, it can absorb the cyclic load of various motion deformations, especially in the measurement of mechanical vibration, it has the ability to compensate for large displacements. Therefore, by covering the connecting cable 6 with a flexible hose 9, the waterproof and dustproof effect of the connecting cable 6 can be further improved.

[0050] In this embodiment, in order to simultaneously clamp the outer flexible tube 9 of the connecting cable 6, the sensor probe also includes a pressure cap 7 and a sealing sleeve 8 located inside the pressure cap 7. Specifically, the flexible tube 9 can be inserted into the receiving cavity formed by the inner wall of the sealing sleeve 8 and the outer surface of the top of the pressure cap 4. By engaging the second end face of the bottom end of the pressure cap 7 with the pressure cap 4, the sealing sleeve 8 can be axially clamped, thereby pressing the flexible tube 9, which further improves the waterproof and dustproof effect of the connecting cable 6.

[0051] In this embodiment, to better clamp the hose and ensure waterproof and dustproof performance, the inner wall of the sealing sleeve 8 is provided with multiple first protrusions, and the outer surface of the top of the pressure cap 4 is provided with multiple second protrusions. Specifically, by providing multiple first protrusions on the inner wall of the sealing sleeve 8, the contact surface between the inner wall of the sealing sleeve 8 and the outer wall of the hose 9 can be increased, thereby improving the clamping force of the sealing sleeve 8 on the hose 9, increasing the coefficient of friction, and enhancing the tightness of the compression. Meanwhile, the multiple second protrusions on the outer surface of the top of the pressure cap 4 allow the pressure cap 4 to fit more tightly against the hose 9, improving the sealing effect. Optionally, the multiple first protrusions are all annular first protrusions arranged circumferentially along the inner wall of the sealing sleeve 8, and the multiple second protrusions are all annular second protrusions arranged circumferentially along the outer surface of the top of the pressure cap 4, thus better matching the shape of the hose 9.

[0052] In practice, the inner wall of the pressure cap 7 and the outer wall of the sensor housing 1 can be press-fitted together, and laser welding can be used to weld the joint. Of course, for ease of installation, the inner wall of the pressure cap 7 and the outer wall of the sensor housing 1 can also be fastened with threads. Those skilled in the art can choose flexibly according to actual needs, and no specific limitation is made here.

[0053] Optionally, based on the above embodiments, in one specific implementation, the maximum outer diameter of the bottom end of the pressure cap 4 is greater than the minimum inner diameter of the pressure cap 7. In this embodiment, when the inner wall of the pressure cap 7 is interference-fitted with the outer wall of the sensor housing 1 or screwed on, an axial thrust can be applied to the pressure cap 4 to ensure the reliability of the pressure cap 4 installation.

[0054] In a preferred embodiment of the present invention, the first end of the circuit board 2 is provided with a stepped plate 21 for soldering the pins of the temperature sensing element. The thickness of the stepped plate 21 is less than the thickness of the circuit board 2 itself. In this embodiment, a temperature sensing element is generally installed inside the sensor. By providing the stepped plate 21 at the first end of the circuit board 2, the pins of the temperature sensing element 22 can be soldered onto the stepped plate 21. Designing the thickness of the stepped plate 21 to be less than the thickness of the circuit board 2 itself increases the distance between the pins of the temperature sensing element 22 and the sensor housing 1 after the temperature sensing element 22 is installed, ensuring sufficient insulation distance and thus improving the insulation performance of the sensor.

[0055] In a preferred embodiment of the present invention, the outer periphery of the bottom of the sensor housing 1 is provided with a first outer conical surface 11 for signal transmission, and the inner wall of the bottom of the sensor housing 1 is also provided with an inner conical surface 12. The first end of the circuit board 2 is provided with a second outer conical surface 23 that cooperates with the inner conical surface 12. In this embodiment, the bottom of the sensor housing 1 is installed at the measured position. By providing the first outer conical surface 11, the sensing area of ​​the sensor can be increased, which is beneficial to improving the signal monitoring effect and thus further improving the signal monitoring sensitivity of the sensor. A vibration and shock sensitive element is installed on the circuit board 2 for detecting the vibration and shock signal at the measured position. By cooperating with the inner conical surface 12 provided on the inner wall of the bottom of the sensor housing 1, the circuit board 2 can not only be radially fixed, but also help the sensor housing 1 to transmit the vibration and shock signal received at the bottom to the vibration and shock sensitive element on the circuit board 2, thereby improving the signal monitoring sensitivity of the sensor.

[0056] In a preferred embodiment of the present invention, the second end of the circuit board 2 is provided with a limiting step 24, and the end of the fixing part 31 away from the mounting part 32 is provided with a bayonet 311 that cooperates with the limiting step 24. In this embodiment, the sensor housing 1 is generally made of metal, and the pressure sleeve 3 can be made of non-metallic material to ensure that the shielding wire in the connecting cable 6 does not come into contact with the metal. Through the cooperation of the limiting step 24 and the bayonet 311, the circuit board 2 can be radially fixed, further improving the fixing effect of the circuit board.

[0057] In a preferred embodiment of the present invention, the end of the fixing part 31 away from the mounting part 32 is further provided with a groove 312 for guiding flow, and the end face of the mounting part 32 is provided with a through hole 321 for ventilation. In this embodiment, when potting compound is poured into the inner cavity of the sensor housing 1, the groove 312 provided at one end of the fixing part 31 can be used to allow the potting compound to flow back, avoiding air bubbles in the gap between the fixing part 31 and the sensor housing 1; the through hole 321 provided at the end face of the mounting part 32 can be used to allow air bubbles to overflow during potting compound filling, reducing the generation of air bubbles.

[0058] Furthermore, based on the above embodiments, in a specific implementation, a sensitive element 25 and a signal conditioning circuit 26 are mounted on the side of the circuit board 2. The sensitive element 25 is used to sense the physical quantity of vibration and impact at the measured position and convert it into a voltage signal. The signal conditioning circuit 26 is used to convert the voltage signal output by the sensitive element 25 into a current signal.

[0059] In this embodiment of the invention, the sensing element 25 mounted on the circuit board 2 can sense the physical quantity of vibration and impact at the measured location and convert it into a voltage signal. However, considering that the sensing element of the sensor generally uses a low voltage power supply, the minimum output signal level of the sensing element 25 is close to zero, and its output voltage analog signal is easily affected by external interference during long-distance transmission, a signal conditioning circuit 26 is also mounted on the circuit board 2 to amplify the voltage signal output by the sensing element 25 and convert it into a current signal to improve the stability of signal transmission. Optionally, a shielding cover is provided on the outside of the signal conditioning circuit 26 to shield interference and further improve the stability of signal transmission.

[0060] Please see Figure 10 and Figure 11 Based on the above embodiments, in a specific implementation, the signal conditioning circuit 26 includes an operational amplifier module 261, a voltage-to-current conversion module 262, and an output current compensation module 263.

[0061] The input terminal of the operational amplifier module 261 is connected to the output terminal of the sensitive element 25, and is used to adjust the voltage level signal output by the sensitive element 25 to a preset level;

[0062] The input terminal of the voltage-to-current conversion module 262 is connected to the output terminal of the operational amplifier module 261, and the output terminal of the voltage-to-current conversion module 262 is connected to the input terminal of the subsequent detection system, which is used to convert the voltage signal output by the operational amplifier module 261 into a current signal.

[0063] The input terminal of the output current compensation module 263 is connected to the first reference voltage, and the output terminal of the output current compensation module 263 is connected to the inverting input terminal of the operational amplifier in the voltage-current conversion module 262. It is used to generate a corresponding compensation current based on the first reference voltage and input it into the voltage-current conversion module 262 to compensate its output current signal.

[0064] Specifically, based on the above embodiments, in some optional embodiments, the output current compensation module 263 includes a first resistor, the first end of the first resistor serves as the input terminal of the output current compensation module 263, and the second end of the first resistor serves as the output terminal of the output current compensation module 263.

[0065] Based on the above embodiments, in a specific embodiment of the present invention, the voltage-to-current conversion module 262 includes a second resistor, a third resistor, a fourth resistor, a first operational amplifier, and an NMOS transistor; the first end of the second resistor serves as the input terminal of the voltage-to-current conversion module 262, the second end of the second resistor is connected to the non-inverting input terminal of the first operational amplifier, the inverting input terminal of the first operational amplifier is connected to the second end of the first resistor, the first end of the third resistor, and the source of the NMOS transistor, respectively, the second end of the third resistor is connected to ground, the output terminal of the first operational amplifier is connected to the first end of the fourth resistor, the second end of the fourth resistor is connected to the gate of the NMOS transistor, and the drain of the NMOS transistor serves as the output terminal of the voltage-to-current conversion module 262.

[0066] Specifically, the first resistor includes resistors R1 and R2 connected in parallel. The first common terminal of resistors R1 and R2 is connected to the first reference voltage VDD, and the second common terminal is connected to the inverting input terminal of the first operational amplifier N1A. The second resistor R3 is a balancing resistor connected to the non-inverting input terminal of the first operational amplifier N1A to balance the resistance at the input terminal of the operational amplifier, perform impedance matching, and reduce offset current. The third resistor is a voltage-to-current conversion resistor, including resistors R4 and R5. Its first common terminal is connected to the inverting input terminal of the first operational amplifier N1A and the source of NMOS transistor T1, and its second common terminal is connected to ground. The fourth resistor R6 is a current-limiting resistor. The output terminal of the first operational amplifier N1A is connected to the gate of NMOS transistor T1 through the fourth resistor R6, and the drain of NMOS transistor T1 is connected to the subsequent detection system. The positive power supply terminal of the first operational amplifier N1A is connected to the power supply voltage, and the ground terminal of the first operational amplifier N1A is grounded. It should be noted that, in addition to NMOS transistors, PMOS transistors, NPN transistors, PNP transistors, and other transistors can also be selected here, with corresponding changes to the circuit structure. This invention does not impose any limitations on these options. In specific implementations, considering the relatively small output current of the sensor, the fourth resistor R6 can be selected with a small resistance value, or even zero, which is equivalent to removing the fourth resistor R6 without affecting the implementation of this technical solution.

[0067] Furthermore, based on the above embodiments, in a specific implementation, the operational amplifier module 261 includes a fifth resistor, a sixth resistor, a seventh resistor, an eighth resistor, and a second operational amplifier. The first end of the fifth resistor is connected to ground, and the second end of the fifth resistor is connected to the non-inverting input terminal of the second operational amplifier and the first end of the sixth resistor. The second end of the sixth resistor is connected to a second reference voltage. The first end of the seventh resistor serves as the input terminal of the operational amplifier module 261, and the second end of the seventh resistor is connected to the inverting input terminal of the second operational amplifier and the first end of the eighth resistor. The second end of the eighth resistor is connected to the output terminal of the second operational amplifier, and their common terminal serves as the output terminal of the operational amplifier module 261.

[0068] Specifically, the fifth resistor R7 and the sixth resistor R8 form a voltage divider circuit. One end of the fifth resistor R7 is grounded, and one end of the sixth resistor R8 is connected to the second reference voltage. The other ends of both resistors R7 and R8 are connected to the non-inverting input of the second operational amplifier N1B. This divided voltage serves as the non-inverting input voltage of the second operational amplifier N1B. The sensitive chip 25 is connected to one end of the seventh resistor R9, and the other end of the seventh resistor R9 is connected to the inverting input of the second operational amplifier N1B. The two ends of the eighth resistor R10 are connected to the inverting input and the output of the second operational amplifier N1B, respectively. At this time, the output of the second operational amplifier N1B receives a conditioned voltage signal, providing an effective input to the voltage-to-current conversion module 262.

[0069] It is understood that the voltage obtained by dividing the second reference voltage using the fifth resistor R7 and the sixth resistor R8 is connected to the non-inverting input of the second operational amplifier N1B. The output impedance of the sensitive element 25, the seventh resistor R9, the eighth resistor R10, and the second operational amplifier N1B constitute an inverting amplifier. The second reference voltage can be the same as or different from the first reference voltage. In this embodiment, for ease of control, both the second and first reference voltages are VDD.

[0070] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. 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 the invention. Therefore, the invention 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 sensor, characterized in that, Includes sensor probes, connecting cables, and electrical connectors; The sensor probe includes a sensor housing. The inner cavity of the sensor housing is provided with a circuit board and a pressure sleeve. The first end of the circuit board is inserted into the bottom of the sensor housing. The pressure sleeve includes a pressure sleeve body with a central opening. The pressure sleeve body includes a fixing part and a mounting part connected to the fixing part. The outer diameter of the fixing part is smaller than the outer diameter of the mounting part. The end of the fixing part away from the mounting part abuts against the second end of the circuit board. The outer surface of the mounting part is in close contact with the inner wall of the sensor housing. A gap is provided between the outer surface of the fixing part and the inner wall of the sensor housing. The inner cavity of the sensor housing is filled with potting compound. The end of the fixing part away from the mounting part is also provided with a slot for guiding flow. The end face of the mounting part is provided with a through hole for ventilation. One end of the connecting cable passes through the central opening of the pressure sleeve and connects to the circuit board, while the other end of the connecting cable connects to the electrical connector.

2. The sensor according to claim 1, characterized in that, The sensor probe further includes a pressure cap, the first end face of the bottom end of the pressure cap abuts against the end of the mounting part away from the fixing part, and a sealing ring is provided between the first end face of the bottom end of the pressure cap and the end of the mounting part away from the fixing part. The outer surface of the bottom end of the pressure cap is engaged with the inner wall of the sensor housing to axially press the sealing ring. The top end face of the pressure cap has an opening for the connecting cable to pass through, and the inner surface of the bottom end of the pressure cap has a tapered groove for installing the sealing ring.

3. The sensor according to claim 2, characterized in that, The sensor probe also includes a pressure cap and a sealing sleeve located inside the pressure cap. A flexible tube is sleeved on the outside of the connecting cable. The inner wall of the pressure cap is connected to the outer wall of the sensor body. The pressure cap is engaged with the second end face of the bottom end of the pressure cap to axially clamp the sealing sleeve. The inner wall of the sealing sleeve and the outer surface of the top end of the pressure cap form a receiving cavity for accommodating the flexible tube. The inner wall of the sealing sleeve is provided with a plurality of first protrusions that cooperate with the outer wall of the flexible tube. The outer surface of the top end of the pressure cap is provided with a plurality of second protrusions that cooperate with the inner wall of the flexible tube.

4. The sensor according to claim 1, characterized in that, The first end of the circuit board is provided with a stepped plate for soldering the pins of the temperature sensing element, and the thickness of the stepped plate is less than the thickness of the circuit board itself.

5. The sensor according to claim 1, characterized in that, The bottom outer periphery of the sensor housing is provided with a first outer conical surface for signal transmission, and the inner wall of the bottom of the sensor housing is also provided with an inner conical surface. The outer periphery of the first end of the circuit board is provided with a second outer conical surface that mates with the inner conical surface.

6. The sensor according to any one of claims 1 to 5, characterized in that, The circuit board has a sensing element and a signal conditioning circuit mounted on its side. The sensing element is used to sense the physical quantity of vibration and impact at the measured position and convert it into a voltage signal. The signal conditioning circuit is used to amplify the voltage signal output by the sensing element and convert it into a current signal.

7. The sensor according to claim 6, characterized in that, The signal conditioning circuit includes an operational amplifier module, a voltage-to-current conversion module, and an output current compensation module; The input terminal of the operational amplifier module is connected to the output terminal of the sensitive element, and is used to adjust the voltage level signal output by the sensitive element to a preset level; The input terminal of the voltage-to-current conversion module is connected to the output terminal of the operational amplifier module, and the output terminal of the voltage-to-current conversion module is connected to the input terminal of the subsequent detection system, for converting the voltage signal output by the operational amplifier module into a current signal; The input terminal of the output current compensation module is connected to a first reference voltage, and the output terminal of the output current compensation module is connected to the inverting input terminal of the operational amplifier in the voltage-current conversion module. The output current compensation module generates a corresponding compensation current based on the first reference voltage and inputs it into the voltage-current conversion module to compensate its output current signal.

8. The sensor according to claim 7, characterized in that, The output current compensation module includes a first resistor, with a first end serving as the input terminal of the output current compensation module and a second end serving as the output terminal of the output current compensation module.

9. The sensor according to claim 8, characterized in that, The voltage-to-current conversion module includes a second resistor, a third resistor, a fourth resistor, a first operational amplifier, and an NMOS transistor; The first end of the second resistor serves as the input terminal of the voltage-to-current conversion module. The second end of the second resistor is connected to the non-inverting input terminal of the first operational amplifier. The inverting input terminal of the first operational amplifier is connected to the second end of the first resistor, the first end of the third resistor, and the source of the NMOS transistor. The second end of the third resistor is connected to ground. The output terminal of the first operational amplifier is connected to the first end of the fourth resistor. The second end of the fourth resistor is connected to the gate of the NMOS transistor. The drain of the NMOS transistor serves as the output terminal of the voltage-to-current conversion module.

10. The sensor according to claim 9, characterized in that, The operational amplifier module includes a fifth resistor, a sixth resistor, a seventh resistor, an eighth resistor, and a second operational amplifier; The first end of the fifth resistor is connected to ground, the second end of the fifth resistor is connected to the non-inverting input of the second operational amplifier and the first end of the sixth resistor, the second end of the sixth resistor is connected to the second reference voltage, the first end of the seventh resistor serves as the input of the operational amplifier module, the second end of the seventh resistor is connected to the inverting input of the second operational amplifier and the first end of the eighth resistor, the second end of the eighth resistor is connected to the output of the second operational amplifier, and their common end serves as the output of the operational amplifier module.

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