CN112815971A

CN112815971A - Sensor

Info

Publication number: CN112815971A
Application number: CN202010170796.0A
Authority: CN
Inventors: 邓柳靖; 王巍松; 施文钦; 李思华; 陈伟琪
Original assignee: Tangzhi Science & Technology Hunan Development Co ltd
Current assignee: Tangzhi Science & Technology Hunan Development Co ltd
Priority date: 2020-03-12
Filing date: 2020-03-12
Publication date: 2021-05-18

Abstract

The invention discloses a sensor, which senses physical quantity of a measured position through a sensitive element on a circuit board and converts the physical quantity into an electric signal, a connecting cable passes through a central opening of a pressing sleeve to be connected with the circuit board and is transmitted to a rear-stage collecting instrument through an electric connector, the circuit board and the pressing sleeve are both arranged in an inner cavity of a sensor shell, a first end of the circuit board is inserted into the bottom of the sensor shell, the pressing sleeve can be attached to the inner wall of the sensor shell through the outer surface of an installation part, one end of a fixing part far away from the installation part is abutted against a second end of the circuit board, the circuit board can be axially compressed, the outer diameter of the fixing part is smaller than that of the installation part, namely, a gap is left between the outer surface of the fixing part and the inner wall of the sensor shell, when pouring sealant is poured into the inner cavity of the sensor shell, the filling, therefore, the fixing effect of the circuit board is improved, and the signal monitoring sensitivity of the sensor is ensured.

Description

Sensor

Technical Field

The invention relates to the technical field of monitoring equipment, in particular to a sensor.

Background

The sensor is used as a monitoring device and widely applied to the fields of machinery, ships, rail transit and the like, wherein a circuit board is arranged in a sensor shell, and physical quantities such as vibration, impact, temperature signals and the like of a measured position are sensed by a sensing element on the circuit board, converted into electric signals and then transmitted through a connecting cable.

In the prior art, a circuit board is generally inserted into a sensor shell, the circuit board is fixed in a pressing mode, and pouring sealant is poured into the sensor shell to achieve the insulating and shockproof effects. However, the fixing mode cannot control the accurate positioning of the circuit board, and the circuit board is easy to loosen in a long-term vibration impact environment, so that the signal monitoring sensitivity of the sensor is reduced.

Disclosure of Invention

In order to solve the technical problems, the invention provides a sensor, which can accurately position a circuit board in the sensor, ensure the fixing effect of the circuit board and improve the signal monitoring sensitivity of the sensor.

The sensor provided by the invention comprises a sensor probe, a connecting cable and an electric connector;

the sensor probe comprises a sensor shell, a circuit board and a pressing sleeve are arranged in an inner cavity of the sensor shell, a first end of the circuit board is inserted into the bottom of the sensor shell, the pressing sleeve comprises a pressing sleeve body with a central hole, the pressing sleeve body comprises a fixing part and an installation part connected to the fixing part, the outer diameter of the fixing part is smaller than that of the installation part, one end, far away from the installation part, of the fixing part abuts against a second end of the circuit board, the outer surface of the installation part is connected with the inner wall of the sensor shell in an attaching mode, a gap is formed between the outer surface of the fixing part and the inner wall of the sensor shell, and pouring sealant is poured into the inner cavity of the;

one end of the connecting cable penetrates through the central opening of the pressing sleeve to be connected with the circuit board, and the other end of the connecting cable is connected with the electric connector.

Preferably, the sensor probe still includes the gland, the first terminal surface of the bottom of gland with the installation department is kept away from the one end of fixed part offsets, just the first terminal surface of the bottom of gland with the installation department is kept away from be provided with the sealing washer between the one end of fixed part, the surface of the bottom of gland with the inner wall cooperation of sensor housing is connected and is compressed tightly with the axial the sealing washer, the confession has been seted up to the terminal surface on the top of gland the opening that connecting cable passed, the internal surface of the bottom of gland is equipped with and is used for the installation the taper groove of sealing washer.

Preferably, the sensor probe further comprises a pressing cap and a sealing sleeve located in the pressing cap, a hose is sleeved outside the connecting cable, the inner wall of the pressing cap is connected with the outer wall of the sensor main body in a matched mode, the pressing cap is matched with the second end face of the bottom end of the pressing cover to clamp the sealing sleeve axially, the inner wall of the sealing sleeve and the outer surface of the top end of the pressing cover form a containing cavity for containing the hose, a plurality of first protrusions matched with the outer wall of the hose are arranged on the inner wall of the sealing sleeve, and a plurality of second protrusions matched with the inner wall of the hose are arranged on the outer surface of the top end of the pressing cover.

Preferably, the first end of the circuit board is provided with a step plate for welding a pin of the temperature measuring element, and the thickness of the step plate is smaller than that of the circuit board.

Preferably, the 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 further provided with an inner conical surface, and the periphery of the first end of the circuit board is provided with a second outer conical surface matched with the inner conical surface.

Preferably, a sensitive element and a signal conditioning circuit are mounted on a side surface of the circuit board, the sensitive element is used for sensing a vibration impact physical quantity of a measured position and converting the vibration impact physical quantity into a voltage signal, and the signal conditioning circuit is used for converting the voltage signal output by the sensitive element into a current signal.

Preferably, the signal conditioning circuit comprises an operational amplification module, a voltage-current conversion module and an output current compensation module;

the input end of the operational amplification module is connected with the output end of the sensitive element and is used for adjusting the level voltage signal output by the sensitive element to a preset level;

the input end of the voltage-current conversion module is connected with the output end of the operational amplification module, and the output end of the voltage-current conversion module is connected with the input end of the rear-stage detection system and is used for converting the voltage signal output by the operational amplification module into a current signal;

the input end of the output current compensation module is connected with a first reference voltage, and the output end of the output current compensation module is connected with the inverting input end of an operational amplifier in the voltage-current conversion module, and is used for generating a corresponding compensation current according to the first reference voltage and inputting the compensation current into the voltage-current conversion module to compensate an output current signal of the voltage-current conversion module.

Preferably, the output current compensation module includes a first resistor, a first end of the first resistor is used as an input end of the output current compensation module, and a second end of the first resistor is used as an output end of the output current compensation module.

Preferably, the voltage-current conversion module comprises a second resistor, a third resistor, a fourth resistor, a first operational amplifier and an NMOS transistor;

the first end of the second resistor is used as the input end of the voltage-current conversion module, the second end of the second resistor is connected with the non-inverting input end of the first operational amplifier, the inverting input end of the first operational amplifier is respectively connected with the second end of the first resistor, the first end of the third resistor and the source electrode of the NMOS tube, the second end of the third resistor is connected with the ground, the output end of the first operational amplifier is connected with the first end of the fourth resistor, the second end of the fourth resistor is connected with the grid electrode of the NMOS tube, and the drain electrode of the NMOS tube is used as the output end of the voltage-current conversion module.

Preferably, the operational amplification module comprises 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 with the ground, the second end of the fifth resistor is respectively connected with the non-inverting input end of the second operational amplifier and the first end of the sixth resistor, the second end of the sixth resistor is connected with a second reference voltage, the first end of the seventh resistor is used as the input end of the operational amplification module, the second end of the seventh resistor is respectively connected with the inverting input end of the second operational amplifier and the first end of the eighth resistor, the second end of the eighth resistor is connected with the output end of the second operational amplifier, and the common end of the eighth resistor is used as the output end of the operational amplification module.

According to the sensor provided by the invention, the physical quantity of the measured position is sensed through the sensitive element arranged on the circuit board and is converted into an electric signal, the connecting cable penetrates through the central opening of the pressing sleeve to be connected with the circuit board, and the generated electric signal is transmitted to the rear-stage collecting instrument through the electric connector. Wherein, circuit board and pressure cover all set up the inner chamber at sensor housing, and the bottom that sensor housing was inserted to the first end of circuit board, the surface that the pressure cover passes through the installation department can be connected with sensor housing's inner wall laminating, the one end of keeping away from the installation department through the fixed part offsets with the second end of circuit board, can axial compress tightly circuit board, and the external diameter of fixed part is less than the external diameter of installation department, that is to say, leave the clearance between the surface of fixed part and sensor housing's the inner wall, when sensor housing's inner chamber was filled with the casting glue, can increase the filling area of casting glue, so that increase the fixing power between the inner wall of pressure cover and sensor housing, thereby improve circuit board's fixed effect. Therefore, compared with the prior art, the sensor provided by the invention can ensure the fixing effect of the internal circuit board and improve the signal monitoring sensitivity of the sensor.

Drawings

In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings needed to be used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments described in the present application, and other drawings can be obtained by those skilled in the art without creative efforts.

Fig. 1 is a schematic structural diagram of a sensor according to an embodiment of the present invention;

FIG. 2 is a schematic structural diagram of a sensor probe according to an embodiment of the present invention;

FIG. 3 is a schematic diagram of another sensor probe according to an embodiment of the present invention;

fig. 4 is a schematic structural diagram of a pressing sleeve according to an embodiment of the present invention;

fig. 5 is a schematic perspective view of a circuit board according to an embodiment of the present invention;

fig. 6 is a schematic front view of a circuit board according to an embodiment of the present invention;

fig. 7 is a schematic rear view of a circuit board according to an embodiment of the invention;

fig. 8 is a left side view schematically illustrating a circuit board according to an embodiment of the present invention;

fig. 9 is a schematic structural diagram of a sensor housing according to an embodiment of the present invention;

fig. 10 is a schematic structural diagram of a signal conditioning circuit according to an embodiment of the present invention;

fig. 11 is a schematic structural diagram of another signal conditioning circuit according to an embodiment of the present invention.

Detailed Description

In order to make those skilled in the art better understand the technical solutions in the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are only a part of the embodiments of the present application, and not all of the embodiments.

It will be understood that when an element is referred to as being "fixed" or "disposed" on another element, it can be directly on the other element or be indirectly disposed on the other element; when an element is referred to as being "connected to" another element, it can be directly connected to the other element or be indirectly connected to the other element.

It will be understood that the terms "length," "width," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," and the like, as used herein, refer to an orientation or positional relationship indicated in the drawings that is solely for the purpose of facilitating the description and simplifying the description, and do not indicate or imply that the device or element being referred to must have a particular orientation, be constructed and operated in a particular orientation, and thus should not be considered as limiting the present application.

Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating 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 the present application, the meaning of a plurality of or a plurality of is two or more unless specifically limited otherwise.

It should be understood that the structures, ratios, sizes, and the like shown in the drawings and described in the specification are only used for understanding and reading the contents disclosed in the specification, and are not used for limiting the conditions that the present application can implement, so the present invention has no technical significance, and any structural modification, ratio relationship change or size adjustment should still fall within the scope of the technical content disclosed in the present application without affecting the efficacy and the achievable purpose of the present application.

As described in the background section, the sensor generally employs inserting the circuit board into the sensor housing, fixing the circuit board by pressing, and pouring the potting adhesive into the sensor housing to achieve the insulating and shockproof effect. However, the fixing mode cannot control the accurate positioning of the circuit board, and the circuit board is easy to loosen in a long-term vibration impact environment, so that the vibration impact sensitivity of the sensor is reduced.

In view of this, an embodiment of the present invention provides a sensor. Referring to fig. 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, a circuit board 2 and a press sleeve 3 are disposed in an inner cavity of the sensor housing 1, a first end of the circuit board 2 is inserted into a bottom of the sensor housing 1, the press sleeve 3 includes a press sleeve body with a central opening, the press sleeve body includes a fixing portion 31 and a mounting portion 32 connected to the fixing portion 31, an outer diameter of the fixing portion 31 is smaller than an outer diameter of the mounting portion 32, an end of the fixing portion 31 away from the mounting portion 32 abuts against a second end of the circuit board 2, an outer surface of the mounting portion 32 is attached to an inner wall of the sensor housing 1, a gap is disposed between the outer surface of the fixing portion 31 and the inner wall of the sensor housing 1, an inner cavity of the sensor housing 1 is filled with a potting, the other end of the connection cable 6 is connected to the electrical connector 102.

In the embodiment of the invention, after sensing the physical quantity of the measured position by the sensitive element arranged on the circuit board 2 and converting the physical quantity into an electric signal, the connecting cable 6 passes through the central opening of the pressing sleeve 3 to be connected with the circuit board 2, and the electric signal is transmitted to the rear-stage collecting instrument by the electric connector 102, wherein, the circuit board 2 and the pressing sleeve 3 are both arranged in the inner cavity of the sensor shell 1, the first end of the circuit board 2 is inserted into the bottom of the sensor shell 1, the pressing sleeve 3 can be attached to the inner wall of the sensor shell 1 by the outer surface of the mounting part 32, the end of the fixing part 31 far away from the mounting part 32 is abutted against the second end of the circuit board 2, the outer diameter of the fixing part 31 is smaller than the outer diameter of the mounting part 32, that is, a gap is left between the outer surface of the fixing part 31 and the inner wall of the sensor shell 1, the filling area of the potting adhesive can be increased so as to increase the holding force between the pressing 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 by the embodiment of the invention can ensure the fixing effect of the internal circuit board and improve the signal monitoring sensitivity of the sensor.

In order to fix the circuit board and simultaneously clamp the connecting cable of the circuit board, on the basis of the above embodiment, in a specific embodiment, the sensor probe further comprises a gland 4, the first end surface of the bottom end of the gland 4 is abutted to one end, away from the fixing part 31, of the mounting part 32, a sealing ring 5 is arranged between the first end surface of the bottom end of the gland 4 and one end, away from the fixing part 31, of the mounting part 32, the outer surface of the bottom end of the gland 4 is connected with the inner wall of the sensor shell 1 in a matched mode to axially compress the sealing ring 5, an opening for the connecting cable 6 to pass through is formed in the end surface of the top end of the gland 4, and a conical groove for mounting the sealing ring 5 is.

In this embodiment, the opening has been seted up to the terminal surface on the top of gland 4, and connecting cable 6 can pass this opening and be connected with inside circuit board 2, and the first terminal surface of the bottom of gland 4 is provided with sealing washer 5 with installation department 32 between keeping away from the one end of fixed part 31, and the surface through the bottom of gland 4 closely laminates with sensor housing 1's inner wall, can axial compress tightly sealing washer 5, and then presss from both sides tight cable 6, makes it reach waterproof dirt-proof effect.

In this embodiment, the sealing ring 5 may be an O-ring, and the inner surface of the bottom end of the gland 4 is provided with a tapered groove in which the O-ring may be installed. Wherein, the volume of sealing washer 5 slightly is greater than the volume of awl groove, can further oppress sealing washer 5 during the installation with axial extrusion connecting cable 6, improves waterproof dustproof effect.

During specific implementation, the maximum outer diameter of the mounting part 32 and the inner wall of the sensor housing 1 can adopt interference fit, the outer surface of the bottom end of the gland 4 and the inner wall of the sensor housing 1 can also adopt interference fit, the mounting reliability is guaranteed, and meanwhile, the joint of the gland 4 and the sensor housing 1 can be welded by using a laser welding process.

In order to further improve the waterproof and dustproof effects of the connecting cable, on the basis of the above embodiment, in a specific embodiment, the sensor probe further comprises a pressing cap 7 and a sealing sleeve 8 located in the pressing cap 7, a hose 9 is sleeved outside the connecting cable 6, the inner wall of the pressing cap 7 is connected with the outer wall of the sensor housing 1 in a matched manner, the pressing cap 7 is matched with the second end face of the bottom end of the pressing cover 4 to axially clamp the sealing sleeve 8, an accommodating cavity for accommodating the hose 9 is formed by the inner wall of the sealing sleeve 8 and the outer surface of the top end of the pressing cover 4, a plurality of first protrusions matched with the outer wall of the hose 9 are arranged on the inner wall of the sealing sleeve 8, and a plurality of second protrusions matched with the inner wall of the hose 9 are arranged on the outer surface of.

In this embodiment, since the hose has good flexibility and fatigue resistance, it can absorb cyclic loads of various motion deformations, and especially has the capability of compensating large displacement in measuring mechanical vibration, the hose 9 is sleeved outside the connecting cable 6, so that the waterproof and dustproof effects of the connecting cable 6 can be further improved.

In this embodiment, in order to be able to simultaneously clamp the external hose 9 of the connection cable 6, the sensor probe further comprises a pressure cap 7 and a sealing sleeve 8 located inside the pressure cap 7. Particularly, the hose 9 can penetrate the inner wall of the sealing sleeve 8 and the accommodating cavity formed by the outer surface of the top end of the gland 4, and the sealing sleeve 8 can be axially clamped through the matching of the second end face of the bottom end of the gland 7 and the gland 4, so that the hose 9 is compressed, and the waterproof and dustproof effects of the connecting cable 6 are further improved.

In this embodiment, for waterproof dirt-proof effect is guaranteed to better clamp hose, the inner wall of seal cover 8 is equipped with a plurality of first archs, and the surface on the top of gland 4 is equipped with a plurality of second archs. Specifically, the inner wall of the sealing sleeve 8 is provided with the plurality of first protrusions, so that the contact surface between the inner wall of the sealing sleeve 8 and the outer wall of the hose 9 can be increased, the clamping force of the sealing sleeve 8 on the hose 9 is improved, and the friction coefficient and the compression tightness degree are increased; and a plurality of second archs that set up at the surface of the top of gland 4 can make gland 4 closely laminate with hose 9 better, improve sealed effect. Optionally, the plurality of first protrusions are annular first protrusions arranged along the circumferential direction of the inner wall of the gland 8, and the plurality of second protrusions are annular second protrusions arranged along the circumferential direction of the outer surface of the top end of the gland 4, so that the shape of the hose 9 can be better matched.

In specific implementation, the inner wall of the pressing cap 7 and the outer wall of the sensor housing 1 can adopt interference fit, and the seam is welded by using a laser welding process. Of course, for installation convenience, the inner wall of the pressing cap 7 and the outer wall of the sensor housing 1 may also be fastened by threads, and those skilled in the art may flexibly select the pressing cap according to actual needs, and no specific limitation is made herein.

Optionally, on the basis of the above embodiments, in a specific implementation manner, the maximum outer diameter of the bottom end of the gland 4 is larger than the minimum inner diameter of the gland 7. In this embodiment, when the inner wall of the pressing cap 7 is connected with the outer wall of the sensor housing 1 in an interference fit manner or screwed, an axial thrust can be applied to the pressing cover 4, and the reliability of the installation of the pressing cover 4 is ensured.

As a preferred embodiment of the present invention, the first end of the circuit board 2 is provided with a step plate 21 for soldering the temperature measuring element pin, and the thickness of the step plate 21 is smaller than that of the circuit board 2 itself. In this embodiment, a temperature measuring element generally needs to be mounted inside the sensor, and the step plate 21 is disposed at the first end of the circuit board 2, so that the pin of the temperature measuring element 22 can be soldered on the step plate 21. The thickness of the step plate 21 is designed to be smaller than the thickness of the circuit board 2, so that after the temperature measuring element 22 is installed, the distance between the pins of the step plate and the sensor shell 1 can be increased, and a sufficient insulation distance is ensured, thereby improving the insulation performance of the sensor.

As a preferred embodiment of the present invention, the outer circumference of the bottom of the sensor housing 1 is provided with a first outer conical surface 11 for signal transmission, the inner wall of the bottom of the sensor housing 1 is further provided with an inner conical surface 12, and the first end of the circuit board 2 is provided with a second outer conical surface 23 matching with the inner conical surface 12. In this embodiment, the bottom of sensor housing 1 is installed in the position of being surveyed, through setting up first external conical surface 11, can increase the area that receives of sensor, is favorable to promoting signal monitoring effect to further improve the signal monitoring sensitivity of sensor. The circuit board 2 is provided with a vibration impact sensitive element for detecting a vibration impact signal of a detected position, and the second outer conical surface 23 is matched with the inner conical surface 12 arranged on the inner wall of the bottom of the sensor shell 1, so that the circuit board 2 can be radially fixed, the sensor shell 1 is facilitated to transmit the vibration impact signal received by the bottom to the vibration impact sensitive element on the circuit board 2, and the signal monitoring sensitivity of the sensor is improved.

In a preferred embodiment of the present invention, a second end of the circuit board 2 is provided with a limit step 24, and one end of the fixing portion 31 away from the mounting portion 32 is provided with a bayonet 311 engaged with the limit step 24. In this embodiment, the sensor housing 1 is generally made of metal, and the pressing sleeve 3 may be made of a non-metal member, so as to ensure that the shielding wire in the connecting cable 6 does not contact with the metal. Through the cooperation of spacing step 24 and bayonet 311, can radially fix circuit board 2, further improve the fixed effect of circuit board.

In a preferred embodiment of the present invention, a fastening groove 312 for guiding flow is further disposed at an end of the fixing portion 31 away from the mounting portion 32, and a through hole 321 for ventilation is disposed at an end surface of the mounting portion 32. In this embodiment, when the potting adhesive is poured into the inner cavity of the sensor housing 1, the slot 312 disposed at one end of the fixing portion 31 can be used for backflow of the potting adhesive, so as to prevent bubbles from existing in the gap between the fixing portion 31 and the sensor housing 1; the through hole 321 provided on the end surface of the mounting portion 32 can be used to overflow bubbles during potting of the potting compound, thereby reducing the generation of bubbles.

Further, on the basis of the above embodiments, in a specific implementation manner, a sensitive element 25 and a signal conditioning circuit 26 are installed on a side surface of the circuit board 2, the sensitive element 25 is used for sensing a vibration impact physical quantity of a measured position and converting the vibration impact physical quantity into a voltage signal, and the signal conditioning circuit 26 is used for converting the voltage signal output by the sensitive element 25 into a current signal.

In the embodiment of the invention, the sensitive element 25 arranged on the circuit board 2 can sense the vibration impact physical quantity of the detected position and convert the vibration impact physical quantity into a voltage signal; however, considering that the sensing element of the sensor is generally powered by low voltage, the level of the minimum output signal of the sensing element 25 is close to zero level, and the voltage analog signal output by the sensing element 25 is susceptible to external interference during long-distance transmission, a signal conditioning circuit 26 is further mounted on the circuit board 2 for amplifying the voltage signal output by the sensing element 25 and converting the voltage signal into a current signal to improve the stability of signal transmission. Optionally, a shielding cover is disposed outside the signal conditioning circuit 26 for shielding interference, so as to further improve stability of signal transmission.

Referring to fig. 10 and fig. 11, on the basis of the foregoing embodiments, in a specific implementation manner, 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;

the input end of the operational amplification module 261 is connected with the output end of the sensing element 25, and is used for adjusting the level voltage signal output by the sensing element 25 to a preset level;

the input end of the voltage-current conversion module 262 is connected with the output end of the operational amplification module 261, and the output end of the voltage-current conversion module 262 is connected with the input end of the rear-stage detection system, and is used for converting the voltage signal output by the operational amplification module 261 into a current signal;

the input end of the output current compensation module 263 is connected to the first reference voltage, and the output end of the output current compensation module 263 is connected to the inverting input end of the operational amplifier in the voltage-to-current conversion module 262, and is configured to generate a corresponding compensation current according to the first reference voltage, and input the compensation current to the voltage-to-current conversion module 262 to compensate the output current signal.

Specifically, on the basis of the above embodiments, in some optional embodiments, the output current compensation module 263 includes a first resistor, a first end of the first resistor is used as an input end of the output current compensation module 263, and a second end of the first resistor is used as an output end of the output current compensation module 263.

On the basis of the foregoing embodiment, in a specific implementation manner 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 is used as the input end of the voltage-current conversion module 262, the second end of the second resistor is connected with the non-inverting input end of the first operational amplifier, the inverting input end of the first operational amplifier is respectively connected with the second end of the first resistor, the first end of the third resistor and the source electrode of the NMOS transistor, the second end of the third resistor is connected with the ground, the output end of the first operational amplifier is connected with the first end of the fourth resistor, the second end of the fourth resistor is connected with the gate electrode of the NMOS transistor, and the drain electrode of the NMOS transistor is used as the output end of the voltage-current conversion module 262.

Specifically, the first resistor comprises a resistor R1 and a resistor R2 which are connected in parallel, a first common terminal of the resistor R1 and the resistor R2 is connected with a first reference voltage VDD, and a second common terminal is connected with an inverting input terminal of the first operational amplifier N1A. The second resistor R3 is a balance resistor, connected to the non-inverting input terminal of the first operational amplifier N1A, and used for balancing the resistors at the input terminals of the operational amplifier, performing impedance matching and reducing offset current. The third resistor is a voltage-current switching resistor and comprises a resistor R4 and a resistor R5, a first common end of the third resistor is connected with the inverting input end of the first operational amplifier N1A and the source electrode of the NMOS transistor T1, and a second common end of the third resistor is connected with the 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 the NMOS transistor T1 through the fourth resistor R6, and the drain of the NMOS transistor T1 is connected to the post-detection system. The positive power supply end of the first operational amplifier N1A is connected to a power supply voltage, and the ground end of the first operational amplifier N1A is grounded. It should be noted that, besides the NMOS transistor, transistors such as a PMOS transistor, an NPN transistor, and a PNP transistor may be selected, and the circuit structure may be changed accordingly, which is not limited herein. In specific implementation, considering that the output current of the sensor is small, the fourth resistor R6 may have a small resistance value, which may even be 0, and this is equivalent to directly removing the fourth resistor R6, and the implementation of the present technical solution is not affected.

Further, in addition to the above-mentioned embodiments, in a specific implementation manner, the operational amplification module 261 includes a fifth resistor, a sixth resistor, a seventh resistor, an eighth resistor, and a second operational amplifier, a first end of the fifth resistor is connected to ground, a second end of the fifth resistor is connected to a non-inverting input terminal of the second operational amplifier and a first end of the sixth resistor, respectively, a second end of the sixth resistor is connected to the second reference voltage, a first end of the seventh resistor is used as an input terminal of the operational amplification module 261, a second end of the seventh resistor is connected to an inverting input terminal of the second operational amplifier and a first end of the eighth resistor, respectively, a second end of the eighth resistor is connected to an output terminal of the second operational amplifier, and a common terminal thereof is used as an output terminal of the operational amplification module 261.

Specifically, the fifth resistor R7 and the sixth resistor R8 form a voltage dividing circuit, wherein one end of the fifth resistor R7 is grounded, one end of the sixth resistor R8 is connected to a second reference voltage, the other end of the fifth resistor R7 and the other end of the sixth resistor R8 are both connected to the non-inverting input terminal of the second operational amplifier N1B, and the divided voltage is used as the non-inverting input terminal voltage of the second operational amplifier N1B. The sensitive chip 25 is connected with one end of a seventh resistor R9, and the other end of the seventh resistor R9 is connected with the inverting input end of a second operational amplifier N1B. Both ends of the eighth resistor R10 are connected to the inverting input terminal of the second operational amplifier N1B and the output terminal of the second operational amplifier N1B, respectively. At this time, the output terminal of the second operational amplifier N1B obtains the conditioned voltage signal, and provides the effective input for the voltage-to-current conversion module 262.

It can be understood that the fifth resistor R7 and the sixth resistor R8 divide the second reference voltage into a voltage, and the voltage is connected to the non-inverting input terminal of the second operational amplifier N1B, and the output impedance of the sensor 25, the seventh resistor R9, the eighth resistor R10 and the second operational amplifier N1B form an inverting amplifier. In this embodiment, for convenience of control, the second reference voltage and the first reference voltage are both VDD.

The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended 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 comprising a sensor probe, a connecting cable and an electrical connector;

2. The sensor of claim 1, wherein the sensor probe further comprises a gland, the first end face of the bottom end of the gland abuts against one end, away from the fixing portion, of the mounting portion, a sealing ring is arranged between the first end face of the bottom end of the gland and one end, away from the fixing portion, of the mounting portion, the outer surface of the bottom end of the gland is connected with the inner wall of the sensor shell in a matched mode to axially compress the sealing ring, an opening for the connecting cable to pass through is formed in the end face of the top end of the gland, and a taper groove for mounting the sealing ring is formed in the inner surface of the bottom end of the gland.

3. The sensor of claim 2, wherein the sensor probe further comprises a pressing cap and a sealing sleeve located in the pressing cap, a hose is sleeved outside the connecting cable, the inner wall of the pressing cap is connected with the outer wall of the sensor body in a matched mode, the pressing cap is matched with the second end face of the bottom end of the pressing cover to clamp the sealing sleeve axially, a containing cavity for containing the hose is formed by the inner wall of the sealing sleeve and the outer surface of the top end of the pressing cover, a plurality of first protrusions matched with the outer wall of the hose are arranged on the inner wall of the sealing sleeve, and a plurality of second protrusions matched with the inner wall of the hose are arranged on the outer surface of the top end of the pressing cover.

4. The sensor of claim 1, wherein the first end of the circuit board is provided with a step plate for soldering the temperature sensing element pin, the step plate having a thickness less than the thickness of the circuit board itself.

5. The sensor of claim 1, wherein the outer periphery of the bottom of the sensor housing is provided with a first outer tapered surface for signal transmission, the inner wall of the bottom of the sensor housing is further provided with an inner tapered surface, and the outer periphery of the first end of the circuit board is provided with a second outer tapered surface which is matched with the inner tapered surface.

6. The sensor according to any one of claims 1 to 5, wherein a sensing element and a signal conditioning circuit are mounted on the side surface of the circuit board, the sensing element is used for sensing the vibration impact physical quantity of the measured position and converting the vibration impact physical quantity into a voltage signal, and the signal conditioning circuit is used for amplifying the voltage signal output by the sensing element and converting the voltage signal into a current signal.

7. The sensor of claim 6, wherein the signal conditioning circuit comprises an operational amplification module, a voltage-to-current conversion module, and an output current compensation module;

8. The sensor of claim 7, wherein the output current compensation module comprises a first resistor, a first end of the first resistor is used as an input end of the output current compensation module, and a second end of the first resistor is used as an output end of the output current compensation module.

9. The sensor of claim 8, wherein the voltage-to-current conversion module comprises a second resistor, a third resistor, a fourth resistor, a first operational amplifier and an NMOS transistor;

10. The sensor of claim 9, wherein the operational amplification module comprises a fifth resistor, a sixth resistor, a seventh resistor, an eighth resistor, and a second operational amplifier;