CN112815976A - Sensor - Google Patents

Abstract

The invention discloses a sensor, which comprises a sensor probe, a connecting cable and an electric connector, wherein the sensor probe comprises a sensor shell, a circuit board, a gland, a pressing cap, a pressing ring and a sealing sleeve, the gland, the pressing cap, the pressing ring and the sealing sleeve are all provided with through holes for the connecting cable to pass through, the sealing sleeve, the pressing ring, the pressing cap and the gland are sequentially sleeved outside the connecting cable from inside to outside, the circuit board is arranged in an inner cavity of the sensor shell, and the outer surface of the first end of the gland is matched and connected with the inner wall of the top of the sensor shell; when the one end of connecting cable is connected with the circuit board of the inner chamber of sensor housing, the inner wall through the second end of gland cooperates with the outer wall of pressure cap, can the axial compress tightly the clamping ring, and then can the axial compress tightly the seal cover through the clamping ring to press from both sides tight connecting cable and make it reach waterproof dirt-proof effect, compare with prior art, can press from both sides tight sensor connecting cable and make it reach waterproof dirt-proof effect, can make the structure of sensor easily miniaturized simultaneously.

Description

Sensor

Technical Field

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

Background

In sensors widely used in the fields of machinery, ships, rail transit, etc., an internal circuit board contains a sensing device for sensing a physical quantity of a measured position, wherein the circuit board generally performs signal transmission with the outside through a connection wire or a connection cable. In order to fix and protect the wires or the connecting cables, a connecting cable locking structure is generally required to be additionally arranged at the tail of the sensor, so that the waterproof and dustproof effects are achieved.

In the prior art, the connecting cable of the sensor is generally fixed by using a connecting cable fixing head which is purchased from the market. Therefore, when designing the structure of the sensor, it is necessary to consider the integration of the attachment method of the connection cable fixing head, which increases the overall size of the sensor design and is not favorable for the miniaturization of the sensor structure.

Disclosure of Invention

To solve the above-described problems, the present invention provides a sensor capable of clamping a sensor connection cable to make it waterproof and dustproof, and capable of easily miniaturizing the structure 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, a gland, a pressing cap, a pressing ring and a sealing sleeve; the gland, the pressing cap, the pressing ring and the sealing sleeve are all provided with through holes for the connecting cables to pass through; the outer side of the connecting cable is sequentially sleeved with a sealing sleeve, a pressure ring, a pressure cap and a gland from inside to outside; the circuit board is arranged in an inner cavity of the sensor shell, the outer surface of the first end of the gland is matched and connected with the inner wall of the top of the sensor shell, the inner wall of the second end of the gland is matched with the outer wall of the pressing cap to axially press the pressing ring, and the pressing ring further axially presses the sealing sleeve;

one end of the connecting cable is connected with the circuit board, and the other end of the connecting cable is connected with the electric connector.

Preferably, a step plate for welding the pin of the temperature measuring element is arranged at the first end of the circuit board, the thickness of the step plate is smaller than that of the circuit board, and the first end of the gland abuts against the second end of the circuit board.

Preferably, the inner wall in the middle part of the sensor housing is provided with a guide groove, and the periphery of the second end of the circuit board is provided with a protrusion matched with the guide groove.

Preferably, the inner wall in the middle part of sensor housing is equipped with the guide slot, the first end of gland is equipped with the bayonet socket, the second end of circuit board be equipped with bayonet socket complex spacing step.

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

the signal conditioning circuit comprises a first charge amplification module, a second charge amplification module and a differential amplification module;

the input end of the first charge amplification module and the input end of the second charge amplification module are respectively connected with two ends of the sensitive element and are used for converting the charge signal output by the sensitive element into a voltage signal;

the first input end and the second input end of the differential amplifying module are respectively connected with the output end of the first charge amplifying module and the output end of the second charge amplifying module, and the output end of the differential amplifying module is connected with the input end of a rear-stage detection system and used for differentially amplifying voltage signals output by the first charge amplifying module and the second charge amplifying module.

Preferably, the first charge amplification module comprises a first operational amplifier, a first capacitor, a first resistor and a second resistor, and the second charge amplification module comprises a second operational amplifier, a second capacitor, a third resistor and a fourth resistor;

the inverting input end of the first operational amplifier is used as the input end of the first charge amplification module, the non-inverting input end of the first operational amplifier is connected with a reference voltage, the output end of the first operational amplifier is used as the output end of the first charge amplification module, two ends of the first capacitor are respectively connected with the inverting input end of the first operational amplifier and the output end of the first operational amplifier, the first end of the first resistor is connected with the inverting input end of the first operational amplifier, the second end of the first resistor is connected with the first end of the second resistor, and the second end of the second resistor is connected with the output end of the first operational amplifier;

the inverting input end of the second operational amplifier is used as the input end of the second charge amplification module, the non-inverting input end of the second operational amplifier is connected to the reference voltage, the output end of the second operational amplifier is used as the output end of the second charge amplification module, two ends of the second capacitor are respectively connected with the inverting input end of the second operational amplifier and the output end of the second operational amplifier, the first end of the third resistor is connected with the inverting input end of the second operational amplifier, the second end of the third resistor is connected with the first end of the fourth resistor, and the second end of the fourth resistor is connected with the output end of the second operational amplifier;

the differential amplification module comprises a fifth resistor, a sixth resistor, a seventh resistor, an eighth resistor and a third operational amplifier;

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

Preferably, the signal conditioning circuit further includes a bootstrap module, configured to boost voltages of the voltage signals output by the first charge amplification module and the second charge amplification module;

the bootstrap module comprises a ninth resistor, a tenth resistor and a third capacitor, wherein a first end of the ninth resistor is connected with a connection node of a second end of the first resistor and a first end of the second resistor, a second end of the ninth resistor is connected with a first end of the third capacitor, a second end of the third capacitor is connected with a first end of the tenth resistor, and a second end of the tenth resistor is connected with a connection node of a second end of the third resistor and a first end of the fourth resistor;

or the like, or, alternatively,

the bootstrap module comprises an eleventh resistor and a fourth capacitor, wherein a first end of the eleventh resistor is connected with a connection node between a second end of the first resistor and a first end of the second resistor, a second end of the eleventh resistor is connected with a first end of the fourth capacitor, and a second end of the fourth capacitor is connected with a connection node between a second end of the third resistor and a first end of the fourth resistor.

Preferably, the signal conditioning circuit further comprises an anti-interference module for enhancing the anti-interference capability of the sensitive element;

the anti-interference module comprises a twelfth resistor, a thirteenth resistor, a fifth capacitor and a sixth capacitor, wherein a first end of the twelfth resistor is connected with a first end of the sensitive element and a first end of the fifth capacitor respectively, a second end of the twelfth resistor is connected with a first end of the thirteenth resistor, a second end of the thirteenth resistor is connected with a second end of the sensitive element and a first end of the sixth capacitor respectively, a common terminal of the twelfth resistor and the thirteenth resistor is connected with the reference voltage, a second end of the fifth capacitor is connected with an input terminal of the first charge amplification module, and a second end of the sixth capacitor is connected with an input terminal of the second charge amplification module;

or the like, or, alternatively,

the anti-interference module comprises a fourteenth resistor, a seventh capacitor and an eighth capacitor, wherein a first end of the fourteenth resistor is connected with a first end of the sensitive element and a first end of the seventh capacitor respectively, a second end of the fourteenth resistor is connected with a second end of the sensitive element and a first end of the eighth capacitor respectively, a second end of the seventh capacitor is connected with an input end of the first charge amplification module, and a second end of the eighth capacitor is connected with an input end of the second charge amplification module.

Preferably, the signal conditioning circuit further comprises a first power supply processing module;

the input end of the first power supply processing module is connected with an input power supply, the first output end of the first power supply processing module is used for providing power supply voltage, and the second output end of the first power supply processing module is used for providing the reference voltage.

Preferably, the signal conditioning circuit further comprises a second power supply processing module;

the input end of the second power supply processing module is connected with the second output end of the first power supply processing module, and the output end of the second power supply processing module is used for supplying power to the temperature measuring element.

The sensor provided by the invention comprises a sensor probe, a connecting cable and an electric connector, wherein the sensor probe comprises a sensor shell, a circuit board, a gland, a pressing cap, a pressing ring and a sealing sleeve, the gland, the pressing cap, the pressing ring and the sealing sleeve are all provided with through holes for the connecting cable to pass through, the sealing sleeve, the pressing ring, the pressing cap and the pressing cap are sequentially sleeved outside the connecting cable from inside to outside, the circuit board is arranged in an inner cavity of the sensor shell, and the outer surface of the first end of the gland is matched and connected with the inner wall of the top of the sensor shell; when one end of the connecting cable is connected with the circuit board of the inner cavity of the sensor shell, the inner wall of the second end of the pressing cover is matched with the outer wall of the pressing cap, the pressing ring can be axially pressed, and the sealing sleeve can be axially pressed through the pressing ring, so that the connecting cable is clamped to achieve the waterproof and dustproof effect. Therefore, compared with the prior art, the sensor provided by the invention can clamp the sensor connecting cable to achieve the waterproof and dustproof effects, and meanwhile, the structure of the sensor can be easily miniaturized.

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 an overall 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 perspective view of a sensor housing according to an embodiment of the present invention;

FIG. 4 is a schematic cross-sectional view of a sensor housing according to an embodiment of the 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 left side view schematically illustrating a circuit board according to an embodiment of the present invention;

fig. 8 is a schematic structural diagram of a signal conditioning circuit according to an embodiment of the present invention;

fig. 9 is a schematic structural diagram of another signal conditioning circuit according to an embodiment of the present invention;

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

fig. 11 is a schematic structural diagram of a first power processing module according to an embodiment of the present invention;

fig. 12 is a schematic structural diagram of a second power processing module according to an embodiment of the present invention;

fig. 13 is a schematic structural diagram of another second power processing module 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.

Referring to fig. 1 to 7, an embodiment of the invention provides a sensor, which includes a sensor probe, a connection cable 7 and an electrical connector 8, wherein the sensor probe includes a sensor housing 1, a circuit board 2, a pressing cover 3, a pressing cap 4, a pressing ring 5 and a sealing sleeve 6, the pressing cover 3, press cap 4, the through-hole that supplies connecting cable 7 to pass is all seted up to clamping ring 5 and seal cover 6, connecting cable 7's the outside, from inside to outside in proper order the cover establish seal cover 6, clamping ring 5, press cap 4, gland 3, circuit board 2 installs in sensor housing 1's inner chamber, the surface of the first end of gland 3 is connected with the inner wall cooperation at sensor housing 1's top, the inner wall of the second end of gland 3 compresses tightly clamping ring 5 with the axial with the outer wall cooperation of pressing cap 4, clamping ring 5 and then the axial compresses tightly seal cover 6, connecting cable 7's one end connecting circuit board 2, connecting cable 7's other end connector 8.

It should be noted that, when the sensor is installed, one end of the sensor housing is inserted into the installation hole of the measured part to ensure the accurate sensing of the physical quantity of the measured position, and the other end is connected with the collecting instrument through the connecting cable and the electric connector to transmit the sensed physical quantity to the collecting instrument. In the invention, the bottom of the sensor shell 1 refers to one end of the sensor shell which is deep into a mounting hole of a tested component, and the top of the sensor shell 1 refers to one end of the sensor shell which is connected with a collecting instrument through a connecting cable 7 and an electric connector 8.

In the embodiment of the invention, the circuit board 2 is arranged in the inner cavity of the sensor shell 1, the physical quantity of the measured position can be sensed through the sensing element on the circuit board 2, the gland 3, the press cap 4, the press ring 5 and the gland 6 are all provided with through holes, the gland 6, the press ring 5, the press cap 4 and the press cap 3 are sequentially sleeved on the outer side of the connecting cable 7 from inside to outside, and the connecting cable 7 can pass through the through holes to be connected with the circuit board 2 for signal transmission. Through the outer surface of the first end of the gland 3 and the inner wall of the top of the sensor housing 1 in a matching connection, axial pressure can be applied to the circuit board 2, so that the circuit board 2 is fixed. Through the inner wall cooperation of the second end of gland 3 and the outer wall of pressure cap 4, can the axial compress tightly clamping ring 5, and then can compress tightly seal cover 6 through clamping ring 5 to press from both sides tight connecting cable 7 and make it reach waterproof dirt-proof effect, from this, need not to consider when the sensor carries out structural design and externally connect the flexible pipe connecting cable fixed head, can make the structure of sensor easily miniaturized. Therefore, compared with the prior art, the sensor connecting cable can be clamped to achieve the waterproof and dustproof effects, and the structure of the sensor can be easily miniaturized.

On the basis of the above embodiments, in some specific embodiments 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, the inner wall of the bottom of the sensor housing 1 is further provided with a first inner conical surface 12, and the outer periphery of the first end of the circuit board 2 is provided with a first outer conical surface 21 matched with the first inner conical surface 12. In this embodiment, when the bottom of the sensor housing 1 is installed at the measured position, the sensing area of the sensor can be increased by arranging the first outer conical surface 11, which is beneficial to improving the signal monitoring effect. And through the cooperation of first interior conical surface 12 and first external cone surface 21, not only can make things convenient for the assembly of sensor housing 1 with circuit board 2, help sensor housing 1 to transmit physical quantities such as vibration and impact signal received to the sensing element on the circuit board 2 subassembly simultaneously to further improve the signal monitoring sensitivity of sensor.

Further, on the basis of the above embodiment, in a specific implementation manner, the first end of the circuit board 2 is provided with a step plate 22 for welding the temperature measuring element pin, the thickness of the step plate 22 is smaller than that of the circuit board 2 itself, and the first end of the gland 3 abuts against the second end of the circuit board 2. In this embodiment, a temperature measuring element generally needs to be installed inside the sensor, and the step plate 22 is disposed at the first end of the circuit board 2, so that the pin of the temperature measuring element 25 can be soldered on the step plate 22. When the circuit board 2 is mounted, the first end of the circuit board is inserted into the bottom of the sensor housing 1, and the other end of the circuit board abuts against the first end of the gland 3, so that the circuit board 2 can be axially fixed. At this time, since the thickness of the step plate 22 is smaller than the thickness of the circuit board 2 itself, after the temperature measuring element 25 is mounted, the distance between the pin and the sensor housing 1 can be increased, so as to ensure a sufficient insulation distance and improve the insulation performance of the sensor.

Further, on the basis of the above embodiments, in some alternative embodiments of the present invention, the inner wall of the middle portion of the sensor housing 1 is provided with the guide groove 13, and the outer circumference of the second end of the circuit board 2 is provided with the protrusion 23 which is matched with the guide groove 13. In this embodiment, through the cooperation of guide slot 13 and arch 23, not only can make things convenient for positioning circuit board 2, can improve the uniformity of sensor sensitivity moreover.

Further, on the basis of the above embodiments, in some alternative embodiments, the first end of the pressing cover 3 is provided with a bayonet, and the second end of the circuit board 2 is provided with a limiting step 24 matched with the bayonet. In this embodiment, through the cooperation of bayonet socket and spacing step 24, can radially fix circuit board 2, improve circuit board 2's fixed effect.

As a preferred embodiment of the present invention, a hose for protection is provided outside the connection cable 7. In this embodiment, since the hose has good flexibility and fatigue resistance, it can absorb cyclic loads of various motion deformations, and particularly has the capability of compensating for large displacement in measuring mechanical vibration, and therefore, the hose is disposed outside the connection cable 7, and the waterproof and dustproof effects of the connection cable 7 can be further improved.

Further, on the basis of the foregoing embodiments, in a specific implementation manner, the circuit board 2 is mounted with a sensor 26 and a signal conditioning circuit, the sensor 26 is configured to sense a physical quantity of a vibration impact at a measured position and convert the physical quantity into a charge signal, and the signal conditioning circuit is configured to convert the charge signal output by the sensor 26 into a voltage signal and amplify the voltage signal.

In the embodiment of the present invention, the sensing element 26 mounted on the circuit board 2 can sense the physical quantity of vibration impact at the measured position and convert the physical quantity into an electric charge signal; however, considering that the charge signals output by the sensor vibration impact sensitive element are weak and are easily interfered, the circuit board 2 is further provided with a signal conditioning circuit for converting the charge signals output by the sensitive element 26 into voltage signals and amplifying the voltage signals, so that the anti-interference capability of signal transmission is improved, and the acquisition of a post-stage acquisition circuit is facilitated. Optionally, a shielding cover is disposed outside the signal conditioning circuit to shield interference, so as to further improve stability of signal transmission.

Referring to fig. 8 to 13, on the basis of the above embodiments, in a specific implementation manner, the signal conditioning circuit includes a first charge amplifying module 271, a second charge amplifying module 272 and a differential amplifying module 273;

the input end of the first charge amplification module 271 and the input end of the second charge amplification module 272 are respectively connected to two ends of the sensor 26, and are used for converting the charge signal output by the sensor 26 into a voltage signal;

the first input end and the second input end of the differential amplification module 273 are respectively connected to the output end of the first charge amplification module 271 and the output end of the second charge amplification module 272, and the output end of the differential amplification module 273 is connected to the input end of the rear-stage detection system, and is configured to differentially amplify the voltage signals output by the first charge amplification module 271 and the second charge amplification module 272.

Specifically, on the basis of the above embodiments, in some optional embodiments of the present invention, the first charge amplifying module 271 includes a first operational amplifier, a first capacitor, a first resistor, and a second resistor, and the second charge amplifying module 272 includes a second operational amplifier, a second capacitor, a third resistor, and a fourth resistor;

the inverting input end of the first operational amplifier is used as the input end of the first charge amplification module 271, the non-inverting input end of the first operational amplifier is connected to the reference voltage, the output end of the first operational amplifier is used as the output end of the first charge amplification module 272, two ends of the first capacitor are respectively connected to the inverting input end of the first operational amplifier and the output end of the first operational amplifier, the first end of the first resistor is connected to the inverting input end of the first operational amplifier, the second end of the first resistor is connected to the first end of the second resistor, and the second end of the second resistor is connected to the output end of the first operational amplifier;

the inverting input end of the second operational amplifier is used as the input end of the second charge amplification module 272, the non-inverting input end of the second operational amplifier is connected with the reference voltage, the output end of the second operational amplifier is used as the output end of the second charge amplification module 272, two ends of the second capacitor are respectively connected with the inverting input end of the second operational amplifier and the output end of the second operational amplifier, the first end of the third resistor is connected with the inverting input end of the second operational amplifier, the second end of the third resistor is connected with the first end of the fourth resistor, and the second end of the fourth resistor is connected with the output end of the second operational amplifier.

In the embodiment of the present invention, the first charge amplifying module 271 is composed of a first operational amplifier N1A, a first capacitor C1, a first resistor R1 and a second resistor R2, and the second charge amplifying module 272 is composed of a second operational amplifier N1B, a second capacitor C2, a third resistor R3 and a fourth resistor R4. The non-inverting input ends of the first operational amplifier N1A and the second operational amplifier N1B are both connected to the reference voltage VDD, the inverting input ends of the first operational amplifier N1A and the second operational amplifier N1B are respectively connected to two ends of the sensor 26, and the output ends of the first operational amplifier N1A and the second operational amplifier N1B are respectively connected to the first input end and the second input end of the differential amplification module 273; a first capacitor C1 and a second capacitor C2 are used for realizing charge-to-voltage conversion, wherein the first capacitor C1 is connected between the inverting input terminal of the first operational amplifier N1A and the output terminal of the first operational amplifier N1A, and the second capacitor C1 is connected between the inverting input terminal of the second operational amplifier N1B and the output terminal of the first operational amplifier N1A; the first resistor R1 and the second resistor R2 are connected in series and then are connected in parallel to two ends of the first capacitor C1, and the first resistor R1 and the second resistor R2 are used for guaranteeing normal static operation of the first operational amplifier N1A; the third resistor R3 and the fourth resistor R4 are connected in series and then connected in parallel to two ends of the second capacitor C2, so as to ensure that the second operational amplifier N1B works normally in a static state.

Further, on the basis of the above embodiments, in some alternative embodiments, the differential amplifying module 273 includes a fifth resistor, a sixth resistor, a seventh resistor, an eighth resistor, and a third operational amplifier; a first end of the fifth resistor is used as a first input end of the differential amplifying module 273, a second end of the fifth resistor is connected to a first end of the sixth resistor and an inverting input end of the third operational amplifier, respectively, a second end of the sixth resistor is connected to the reference voltage, a first end of the seventh resistor is used as a second input end of the differential amplifying module 273, a second end of the seventh resistor is connected to a first end of the eighth resistor and a non-inverting input end of the third operational amplifier, respectively, a second end of the eighth resistor is connected to an output end of the third operational amplifier, and a common end of the eighth resistor is used as an output end of the differential amplifying module 273.

In this embodiment of the present invention, the differential amplifying module 273 includes two symmetrical sets of a fifth resistor R5 and a sixth resistor R6, a seventh resistor R7 and an eighth resistor R8, and a third operational amplifier N1C. A first end of the fifth resistor R5 and a first end of the seventh resistor R7 are respectively connected to the output end of the first charge amplification module 271 and the output end of the second charge amplification module 272, and a second end of the fifth resistor R5 and a second end of the seventh resistor R7 are respectively connected to the inverting input end of the third operational amplifier N1C and the non-inverting input end of the third operational amplifier N1C; a first end of the sixth resistor R6 is connected to the reference voltage VDD, and a second end of the sixth resistor R6 is connected to a connection node between a second end of the fifth resistor R5 and the inverting input terminal of the third operational amplifier N1C; a first end of the eighth resistor R8 is connected to a connection node between a second end of the seventh resistor R7 and the non-inverting input terminal of the third operational amplifier N1C, a second end of the eighth resistor R8 is connected to the output terminal of the third operational amplifier N1C, and a common terminal of the eighth resistor R8 is connected to the input terminal of the post-detection system; the positive power supply end of the third operational amplifier N1C is connected to the power supply voltage VCC, and the ground end of the third operational amplifier N1C is grounded.

Further, on the basis of the foregoing embodiments, in some optional embodiments, the signal conditioning circuit further includes a bootstrap module 274, configured to boost the voltage of the voltage signal output by the first charge amplification module 271 and the second charge amplification module 272. Bootstrap module 274 includes ninth, tenth and third resistors; the first end of the ninth resistor is connected with the connection node of the second end of the first resistor and the first end of the second resistor, the second end of the ninth resistor is connected with the first end of the third capacitor, the second end of the third capacitor is connected with the first end of the tenth resistor, and the second end of the tenth resistor is connected with the connection node of the second end of the third resistor and the first end of the fourth resistor.

In the embodiment of the present invention, considering that the gain of the sensing element 26 is too small in the low frequency range, the bootstrap module 274 is designed between the first charge amplification module 271 and the second charge amplification module 272, so as to raise the voltage of the voltage signal output by the first charge amplification module 271 and the second charge amplification module 272. Specifically, the bootstrap module 274 is composed of a ninth resistor R9, a tenth resistor R10 and a third capacitor C3. The ninth resistor R9 and the tenth resistor R10 are both current-limiting resistors, the first end of the ninth resistor R9 is connected between the first resistor R1 and the second resistor R2, and the second end of the ninth resistor R9 is connected with one end of the third capacitor C3; a first end of the tenth resistor R10 is connected between the third resistor R3 and the fourth resistor R4, and a second end of the tenth resistor R10 is connected to the other end of the third capacitor C3; the third capacitor C3 is a bootstrap capacitor, and is used to boost the voltage of the voltage signals output by the first charge amplification module 271 and the second charge amplification module 272, so as to compensate the shortage that the gain of the sensing element 26 is too small in the low frequency range.

Optionally, in another specific embodiment, the bootstrap module 274 includes an eleventh resistor and a fourth capacitor; the first end of the eleventh resistor is connected with a connection node between the second end of the first resistor and the first end of the second resistor, the second end of the eleventh resistor is connected with the first end of the fourth capacitor, and the second end of the fourth capacitor is connected with a connection node between the second end of the third resistor and the first end of the fourth resistor. In this embodiment, the bootstrap module 274 is composed of an eleventh resistor R11 and a fourth capacitor C4.

As a preferred embodiment of the present invention, the signal conditioning circuit further includes an anti-interference module 275 for improving the anti-interference capability of the sensing element 26; the anti-interference module 275 includes a twelfth resistor, a thirteenth resistor, a fifth capacitor and a sixth capacitor, wherein a first end of the twelfth resistor is connected to the first end of the sensing element 26 and the first end of the fifth capacitor, a second end of the twelfth resistor is connected to the first end of the thirteenth resistor, a second end of the thirteenth resistor is connected to the second end of the sensing element 26 and the first end of the sixth capacitor, a common end of the twelfth resistor and the thirteenth resistor is connected to the reference voltage, a second end of the fifth capacitor is connected to the input end of the first charge amplification module 271, and a second end of the sixth capacitor is connected to the input end of the second charge amplification module 272.

Specifically, the immunity module 275 is composed of an eleventh resistor R11, a fourth capacitor C4 and a fifth capacitor C5, wherein the eleventh resistor R11 is connected to two ends of the sensor 26, the fourth capacitor C4 is connected in series between the first end of the sensor 26 and the input end of the first charge amplification module 271, and the fifth capacitor C5 is connected in series between the second end of the sensor 26 and the input end of the second charge amplification module 272, so that the immunity of the sensor 26 can be effectively improved.

Optionally, in another specific embodiment, the anti-interference module 275 includes a fourteenth resistor, a seventh capacitor and an eighth capacitor, where a first end of the fourteenth resistor is connected to the first end of the sensing element 26 and the first end of the seventh capacitor, a second end of the fourteenth resistor is connected to the second end of the sensing element 26 and the first end of the eighth capacitor, a second end of the seventh capacitor is connected to the input end of the first charge amplification module 271, and a second end of the eighth capacitor is connected to the input end of the second charge amplification module 272. In this embodiment, the interference rejection module 275 includes a fourteenth resistor R14, a seventh capacitor C7, and an eighth capacitor C8.

As a preferred embodiment of the present invention, the signal conditioning circuit further comprises a first power processing module 276; the input end of the first power processing module 276 is connected to an input power, the first output end of the first power processing module 276 is used for providing a power voltage, and the second output end of the first power processing module 276 is used for providing a reference voltage.

In the embodiment of the present invention, in order to ensure the stability of the signal conditioning circuit, a first power processing module 276 is added in the signal conditioning circuit, an input end of the first power processing module is connected to an external input power, a first output end provides a stable power voltage for the signal conditioning circuit, and a second output end provides a stable reference voltage for the signal conditioning circuit, so as to improve the precision of the reference voltage.

Specifically, in the above embodiment, the first power processing module 276 includes a diode, a fifteenth resistor, a ninth capacitor, a tenth capacitor, and a first voltage regulator; the anode of the diode is used as the input end of the first power processing module 276, the cathode of the diode is connected to the first end of the fifteenth resistor and the first end of the ninth capacitor, respectively, the common end of the diode is used as the first output end of the first power processing module 276, the second end of the fifteenth resistor is connected to the first end of the tenth capacitor and the cathode of the first voltage regulator tube, respectively, the common end of the diode is used as the second output end of the first power processing module 276, and the second end of the ninth capacitor, the second end of the tenth capacitor and the anode of the first voltage regulator tube are all connected to ground.

In the embodiment of the present invention, the first power processing module 276 is composed of a diode V1, a fifteenth resistor R15, a ninth capacitor C9, a tenth capacitor C10, and a first voltage regulator Z1; the diode V1 is an anti-reverse diode, and the anode of the diode V1 is connected with an external input power supply; the ninth capacitor C9 is a filter capacitor, and has a first terminal connected to the cathode of the diode V1 and a second terminal connected to ground; a connection node between the cathode of the diode V1 and the first end of the ninth capacitor C9 outputs a power supply voltage VCC which supplies power to a positive power supply end of an operational amplifier in the signal conditioning circuit; the fifteenth resistor R15 is a current-limiting resistor for limiting the maximum current flowing through the first regulator tube Z1, and has a first end connected to the connection node between the cathode of the diode V1 and the first end of the ninth capacitor C9; a tenth capacitor C10 is a filter capacitor, a first voltage regulator tube Z1 is a voltage regulator diode, the first end of the tenth capacitor C10 and the cathode of the first voltage regulator tube Z1 are both connected with the second end of a fifteenth resistor R15, and the first end of the tenth capacitor C10 and the anode of the first voltage regulator tube Z1 are both connected with the ground; the connection node between the second terminal of the fifteenth resistor R15, the first terminal of the tenth capacitor C10, and the cathode of the first regulator tube Z1 outputs the reference voltage VDD, which provides the reference voltage for the first charge amplification module 271, the second charge amplification module 272, the differential amplification module 273, and the like. Optionally, the sensing element 26 may also be powered by the reference voltage VDD; when the temperature measuring element arranged in the sensor outputs analog signals such as a platinum resistor temperature sensitive device, the temperature measuring element outputting the analog signals can also be directly powered by the reference voltage VDD.

Further, on the basis of the above embodiments, in some optional embodiments, the signal conditioning circuit further includes a second power processing module 277; the input end of the second power processing module 277 is connected to the second output end of the first power processing module 276, and the output end of the second power processing module 277 is used for supplying power to the temperature measuring element.

In the embodiment of the present invention, in consideration that the temperature measuring element installed inside the sensor may be a digital signal output, and the sensing element 26 is an analog signal output, in order to avoid mutual interference, a second power processing module 277 is further added to the signal conditioning circuit, an input end of the second power processing module 277 is connected to a second output end of the first power processing module 276, and an output end of the second power processing module is used for supplying power to the temperature measuring element for outputting the digital signal.

Optionally, in a specific embodiment, the second power processing module 277 includes a sixteenth resistor, an eleventh capacitor, and a second voltage regulator; the first end of the sixteenth resistor is used as the input end of the second power processing module 277, the second end of the sixteenth resistor is respectively connected with the first end of the eleventh capacitor and the cathode of the second voltage regulator tube, the common end of the sixteenth resistor is used as the output end of the second power processing module 277, and the second end of the eleventh capacitor and the anode of the second voltage regulator tube are both connected with the ground.

In the embodiment of the present invention, the second power processing module 277 includes a sixteenth resistor R16, an eleventh capacitor C11, and a second voltage regulator tube Z2; the sixteenth resistor R16 is a current-limiting resistor for limiting the maximum current flowing through the second voltage regulator tube Z2, and the first end of the sixteenth resistor R16 is connected to the reference voltage VDD; an eleventh capacitor C11 is a filter capacitor, a second voltage regulator tube Z2 is a voltage regulator diode, a first end of the eleventh capacitor C11 and a cathode of the second voltage regulator tube Z2 are both connected with a second end of a sixteenth resistor R16, and a first end of the eleventh capacitor C11 and an anode of the second voltage regulator tube Z2 are both connected with the ground; and the connection node of the second end of the sixteenth resistor R16, the first end of the eleventh capacitor C11 and the cathode of the second voltage regulator tube Z2 is used as the output end of the second power processing module 277 and supplies power for the temperature measuring element for outputting digital signals. That is to say, in this embodiment, the reference voltage VDD supplies power to the temperature measuring element outputting the digital signal after passing through the separate voltage stabilizing circuit, and the circuit is simple and has low cost.

Optionally, in another specific embodiment, the second power processing module 277 includes a fourth operational amplifier, a seventeenth resistor, and a twelfth capacitor; the non-inverting input terminal of the fourth operational amplifier is used as the input terminal of the second power processing module 277, the inverting input terminal of the fourth operational amplifier is connected to the output terminal of the fourth operational amplifier and the first terminal of the seventeenth resistor, the second terminal of the seventeenth resistor is connected to the first terminal of the twelfth capacitor, the common terminal of the seventeenth resistor is used as the output terminal of the second power processing module 277, and the second terminal of the twelfth capacitor is connected to ground.

In the embodiment of the present invention, the second power processing module 277 includes a fourth operational amplifier N1D, a seventeenth resistor R17, and a twelfth capacitor C12; the fourth operational amplifier N1D is used as a voltage follower, the non-inverting input terminal of the fourth operational amplifier is connected to the reference voltage VDD, and the inverting input terminal of the fourth operational amplifier is short-circuited with the output terminal; the seventeenth resistor R17 is a current-limiting resistor, and has a first end connected to the node connecting the inverting input terminal and the output terminal of the fourth operational amplifier N1D; the twelfth capacitor C12 is a filter capacitor, and has a first end connected to the second end of the seventeenth resistor R17, and a second end connected to ground; the connection node of the second end of the seventeenth resistor R17 and the first end of the twelfth capacitor C12 serves as the output end of the second power processing module 277 and supplies power to the temperature measuring element outputting the digital signal. That is to say, in this embodiment, the reference voltage VDD supplies power to the temperature measuring element outputting the digital signal after passing through the voltage follower circuit, so as to realize voltage follower and improve the driving capability.

As a preferred embodiment of the present invention, the signal conditioning circuit further comprises an electrostatic protection module for providing electrostatic protection; the electrostatic protection module comprises a first electrostatic discharge tube, a second electrostatic discharge tube, a third electrostatic discharge tube and a fourth electrostatic discharge tube; the first end of the first electrostatic discharge tube is connected to the input end of the first power processing module 276, the first end of the second electrostatic discharge tube is connected to the second output end of the first power processing module 276, the first end of the third electrostatic discharge tube is connected to the output end of the differential amplification module 273, the first end of the fourth electrostatic discharge tube is connected to the output end of the temperature measuring element, and the second end of the first electrostatic discharge tube, the second end of the second electrostatic discharge tube, the second end of the third electrostatic discharge tube and the second end of the fourth electrostatic discharge tube are all connected to the ground.

In the embodiment of the invention, in order to improve the anti-static capability of the signal conditioning circuit, the signal conditioning circuit is also provided with the static protection module which can provide static protection. Specifically, the electrostatic protection module includes a first electrostatic discharge tube ESD1, a second electrostatic discharge tube ESD2, a third electrostatic discharge tube ESD3, and a fourth electrostatic discharge tube ESD 4; the first end of the first electrostatic discharge tube ESD1 is connected to the input end of the first power processing module 276, the first end of the second electrostatic discharge tube ESD2 is connected to the second output end of the first power processing module 276, the first end of the third electrostatic discharge tube ESD3 is connected to the output end of the differential amplification module 273, the first end of the fourth electrostatic discharge tube ESD4 is connected to the output end of the temperature measuring element, and the second ends of the first electrostatic discharge tube ESD1, the second electrostatic discharge tube ESD2, the third electrostatic discharge tube ESD3 and the fourth electrostatic discharge tube ESD4 are all connected to ground, so as to perform electrostatic protection on the power input interface, the reference voltage output interface, the sensitive element output interface and the temperature measuring element output interface. Optionally, when the encoder chip is installed inside the sensor, the first end of the second electrostatic discharge tube ESD2 may be selectively connected to the output end of the encoder chip, so as to perform electrostatic protection on the output interface of the encoder chip.

Optionally, a resistor R18 is connected between the input terminal of the first charge amplification module 271 and the first terminal of the sensor 26, and a resistor R19 is connected between the input terminal of the second charge amplification module 272 and the second terminal of the sensor 26, so that the interference immunity of the input signals of the first charge amplification module 271 and the second charge amplification module 272 can be improved.

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 (10)

1. A sensor comprising a sensor probe, a connecting cable and an electrical connector;

the sensor probe comprises a sensor shell, a circuit board, a gland, a pressing cap, a pressing ring and a sealing sleeve; the gland, the pressing cap, the pressing ring and the sealing sleeve are all provided with through holes for the connecting cables to pass through; the outer side of the connecting cable is sequentially sleeved with a sealing sleeve, a pressure ring, a pressure cap and a gland from inside to outside; the circuit board is arranged in an inner cavity of the sensor shell, the outer surface of the first end of the gland is matched and connected with the inner wall of the top of the sensor shell, the inner wall of the second end of the gland is matched with the outer wall of the pressing cap to axially press the pressing ring, and the pressing ring further axially presses the sealing sleeve;

one end of the connecting cable is connected with the circuit board, and the other end of the connecting cable is connected with the electric connector.

2. The sensor of claim 1, wherein the first end of the circuit board is provided with a step plate for soldering the temperature measuring element pin, the thickness of the step plate is smaller than the thickness of the circuit board, and the first end of the gland abuts against the second end of the circuit board.

3. The sensor of claim 2, wherein the inner wall of the middle portion of the sensor housing is provided with a guide groove, and the outer circumference of the second end of the circuit board is provided with a protrusion engaged with the guide groove.

4. The sensor of claim 3, wherein the first end of the gland is provided with a bayonet, and the second end of the circuit board is provided with a limiting step matched with the bayonet.

5. The sensor according to any one of claims 1 to 4, wherein a sensing element and a signal conditioning circuit are mounted on the circuit board, the sensing element is used for sensing the vibration impact physical quantity of a measured position and converting the vibration impact physical quantity into a charge signal, and the signal conditioning circuit is used for converting the charge signal output by the sensing element into a voltage signal and amplifying the voltage signal;

the signal conditioning circuit comprises a first charge amplification module, a second charge amplification module and a differential amplification module;

the input end of the first charge amplification module and the input end of the second charge amplification module are respectively connected with two ends of the sensitive element and are used for converting the charge signal output by the sensitive element into a voltage signal;

the first input end and the second input end of the differential amplifying module are respectively connected with the output end of the first charge amplifying module and the output end of the second charge amplifying module, and the output end of the differential amplifying module is connected with the input end of a rear-stage detection system and used for differentially amplifying voltage signals output by the first charge amplifying module and the second charge amplifying module.

6. The sensor of claim 5, wherein the first charge amplification module comprises a first operational amplifier, a first capacitor, a first resistor, and a second resistor, and the second charge amplification module comprises a second operational amplifier, a second capacitor, a third resistor, and a fourth resistor;

the inverting input end of the first operational amplifier is used as the input end of the first charge amplification module, the non-inverting input end of the first operational amplifier is connected with a reference voltage, the output end of the first operational amplifier is used as the output end of the first charge amplification module, two ends of the first capacitor are respectively connected with the inverting input end of the first operational amplifier and the output end of the first operational amplifier, the first end of the first resistor is connected with the inverting input end of the first operational amplifier, the second end of the first resistor is connected with the first end of the second resistor, and the second end of the second resistor is connected with the output end of the first operational amplifier;

the inverting input end of the second operational amplifier is used as the input end of the second charge amplification module, the non-inverting input end of the second operational amplifier is connected to the reference voltage, the output end of the second operational amplifier is used as the output end of the second charge amplification module, two ends of the second capacitor are respectively connected with the inverting input end of the second operational amplifier and the output end of the second operational amplifier, the first end of the third resistor is connected with the inverting input end of the second operational amplifier, the second end of the third resistor is connected with the first end of the fourth resistor, and the second end of the fourth resistor is connected with the output end of the second operational amplifier;

the differential amplification module comprises a fifth resistor, a sixth resistor, a seventh resistor, an eighth resistor and a third operational amplifier;

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

7. The sensor of claim 6, wherein the signal conditioning circuit further comprises a bootstrap module for boosting the voltage of the voltage signals output by the first and second charge amplification modules;

the bootstrap module comprises a ninth resistor, a tenth resistor and a third capacitor, wherein a first end of the ninth resistor is connected with a connection node of a second end of the first resistor and a first end of the second resistor, a second end of the ninth resistor is connected with a first end of the third capacitor, a second end of the third capacitor is connected with a first end of the tenth resistor, and a second end of the tenth resistor is connected with a connection node of a second end of the third resistor and a first end of the fourth resistor;

or the like, or, alternatively,

the bootstrap module comprises an eleventh resistor and a fourth capacitor, wherein a first end of the eleventh resistor is connected with a connection node between a second end of the first resistor and a first end of the second resistor, a second end of the eleventh resistor is connected with a first end of the fourth capacitor, and a second end of the fourth capacitor is connected with a connection node between a second end of the third resistor and a first end of the fourth resistor.

8. The sensor of claim 6, wherein the signal conditioning circuit further comprises an anti-jamming module for enhancing the anti-jamming capability of the sensing element;

the anti-interference module comprises a twelfth resistor, a thirteenth resistor, a fifth capacitor and a sixth capacitor, wherein a first end of the twelfth resistor is connected with a first end of the sensitive element and a first end of the fifth capacitor respectively, a second end of the twelfth resistor is connected with a first end of the thirteenth resistor, a second end of the thirteenth resistor is connected with a second end of the sensitive element and a first end of the sixth capacitor respectively, a common terminal of the twelfth resistor and the thirteenth resistor is connected with the reference voltage, a second end of the fifth capacitor is connected with an input terminal of the first charge amplification module, and a second end of the sixth capacitor is connected with an input terminal of the second charge amplification module;

or the like, or, alternatively,

the anti-interference module comprises a fourteenth resistor, a seventh capacitor and an eighth capacitor, wherein a first end of the fourteenth resistor is connected with a first end of the sensitive element and a first end of the seventh capacitor respectively, a second end of the fourteenth resistor is connected with a second end of the sensitive element and a first end of the eighth capacitor respectively, a second end of the seventh capacitor is connected with an input end of the first charge amplification module, and a second end of the eighth capacitor is connected with an input end of the second charge amplification module.

9. The sensor of claim 6, wherein the signal conditioning circuit further comprises a first power processing module;

the input end of the first power supply processing module is connected with an input power supply, the first output end of the first power supply processing module is used for providing power supply voltage, and the second output end of the first power supply processing module is used for providing the reference voltage.

10. The sensor of claim 9, wherein the signal conditioning circuit further comprises a second power processing module;

the input end of the second power supply processing module is connected with the second output end of the first power supply processing module, and the output end of the second power supply processing module is used for supplying power to the temperature measuring element.

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