Capacitive sensor with symmetrical differential electrodes

Abstract

The utility model relates to a capacitive sensor with symmetrical differential electrodes, which comprises a shell, the symmetrical differential electrodes, an insulating sleeve and a cable, and is characterized in that compared with a single-electrode sensor, the capacitive sensor with the symmetrical differential electrodes has the advantages that an equipotential ring structure is omitted, so that the sensor is simpler in structure, and in addition, in the same shell space, the structure of the sensor is simplified; the end face area of the symmetrical differential electrode can be designed to be larger, according to a plate capacitance calculation formula, the larger the electrode end face area is, the larger the capacitance value is, and according to the structure of the symmetrical differential electrode, formed differential capacitance signals are higher in common-mode interference resistance in the transmission process, the detection precision of the blade tip clearance of the aero-engine can be effectively improved, and the detection accuracy of the blade tip clearance of the aero-engine can be improved. The single-layer shielding differential cable is adopted for differential capacitance signal transmission, and compared with a tri-coaxial cable, the structure is simpler, the reliability is higher, and the cost is reduced.

Description

Technical Field

[0001] The present application relates to the field of sensor technology, and in particular to a capacitive sensor with symmetrical differential electrodes. Background Art

[0002] Tip clearance is an important parameter that affects the efficiency of aircraft engines. In order to ensure that the gap between the tip of the rotor blade and the inner wall of the casing of an aircraft engine is within the allowable range, it is generally necessary to detect the tip clearance through a detection device. The most commonly used detection method is the capacitance method.

[0003] At present, a capacitive sensor with a single electrode structure is generally used to detect the blade tip clearance. Since the capacitance signal output by the capacitive sensor during the detection process is very small and the ability to resist common-mode interference is insufficient, the signal output by the sensor needs to be transmitted to the back-end detection instrument through a longer cable. Long-line transmission will introduce a large parasitic capacitance. The large and randomly changing parasitic capacitance can easily interfere with the detection process, resulting in low detection accuracy of the blade tip clearance. The single-electrode capacitive sensor probe needs to use a triaxial or quasi-triaxial cable for shielding and anti-interference. The triaxial cable uses two layers of shielding, which is expensive and has low reliability.

[0004] Therefore, how to improve the detection accuracy of the blade tip clearance of an aircraft engine, reduce the cost, and improve the reliability of sensor signal transmission is a technical problem that those skilled in the art urgently need to solve. Utility Model Content

[0005] In order to solve the above technical problems, the purpose of this application is to provide a capacitive sensor with symmetrical differential electrodes; the capacitive sensor with symmetrical differential electrodes provided in this application can effectively suppress common-mode interference, improve the detection accuracy of the tip clearance of an aircraft engine, effectively reduce costs, and effectively improve the reliability of sensor signal transmission.

[0006] The technical solutions provided in this application are as follows:

[0007] A capacitive sensor with symmetrical differential electrodes, comprising: a housing, symmetrical differential electrodes, an insulating sleeve, and a cable;

[0008] An accommodating space with an opening is provided in the shell;

[0009] The symmetrical differential electrode and the insulating sleeve are arranged in the accommodating space, and the first end of the symmetrical differential electrode is close to the opening;

[0010] The insulating sleeve is arranged on the outside of the symmetrical differential electrode and is used to insulate and isolate the symmetrical differential electrode from the shell;

[0011] The cable is connected to the second end of the symmetrical differential electrode and is used to transmit the differential capacitance signal sensed by the symmetrical differential electrode.

[0012] Optionally, it further comprises: a lead electrode;

[0013] A first through hole is provided on the outer wall of the first end of the insulating sleeve, and the first end of the lead electrode passes through the first through hole of the insulating sleeve and is connected to the second end of the symmetrical differential electrode;

[0014] The second end of the lead electrode is provided with a mounting head, and the mounting head is located on a side of the first through hole away from the symmetrical differential electrode. The second end of the lead electrode is connected to the cable.

[0015] Optionally, it also includes a lead-in plate and a lead-in wire, wherein the lead-in plate is connected to the second end of the lead-in electrode, the first end of the lead-in wire is connected to the lead-in plate by laser welding or resistance welding, and the second end of the lead-in wire is connected to the cable.

[0016] Optionally, a step is provided in the housing;

[0017] The outer wall of the first end of the insulating sleeve abuts against the step in the shell.

[0018] Optionally, a mounting table is provided in the housing, and a second through hole corresponding to the position of the first through hole is provided on the mounting table; the outer wall of the first end of the insulating sleeve abuts against the first end surface of the mounting table;

[0019] The first end of the lead electrode passes through the second through hole of the mounting table and the first through hole of the insulating sleeve, and is connected to the second end of the symmetrical differential electrode;

[0020] The mounting head at the second end of the lead electrode is used to fix the lead electrode to the second end surface of the mounting table;

[0021] An insulating pad is provided between the current lead plate and the second end surface of the mounting table, and the insulating pad is used to insulate and isolate the current lead plate from the shell.

[0022] Optionally,

[0023] The outer wall of the second end of the symmetrical differential electrode abuts against the inner wall of the first end of the insulating sleeve;

[0024] The outer wall of the second end of the symmetrical differential electrode is provided with a first chamfer;

[0025] The outer wall of the first end of the insulating sleeve is provided with a second chamfer.

[0026] Optionally, the symmetrical differential electrode includes a first electrode and a second electrode, and the number of the lead electrode, the lead sheet, and the lead wire are respectively 2;

[0027] The first end of the first lead electrode is connected to the second end of the first electrode, and the first end of the second lead electrode is connected to the second end of the second electrode;

[0028] The second end of the first lead electrode is connected to the first lead wire through the first lead sheet, and the second end of the second lead electrode is connected to the second lead wire through the second lead sheet.

[0029] Optionally,

[0030] An insulating sheet is provided between the symmetric planes of the first electrode and the second electrode, and the insulating sheet is used to insulate and isolate the first electrode from the second electrode.

[0031] Optionally,

[0032] The joints between the insulating sheet, the first electrode, the second electrode, the insulating sleeve and the shell are all provided with metallized connecting edges, which are sealed by welding.

[0033] Optionally,

[0034] The first electrode and the second electrode are made of high temperature resistant metal or alloy;

[0035] The insulating sleeve and the insulating sheet are made of one or more of high-temperature resistant alumina ceramics, polyimide, and polytetrafluoroethylene.

[0036] Optionally,

[0037] The insulating sleeve is connected to the shell by vacuum brazing, hydrogen or inert gas shielded welding to prevent the symmetrical differential electrode from falling out.

[0038] Optionally, the second end of the symmetrical differential electrode is provided with a threaded hole, and the first end of the lead electrode is provided with an external thread;

[0039] The first end of the lead electrode passes through the first through hole of the insulating sleeve and is connected to the threaded hole of the second end of the symmetrical differential electrode;

[0040] The mounting head fixes the electrical limiter to the insulating sleeve.

[0041] Optionally,

[0042] The lead electrode is a screw.

[0043] Optionally, it further comprises: an electrical connector, the electrical connector comprising a connector housing and a pin;

[0044] The connector housing is fixedly connected to the housing and the pin;

[0045] The first end of the pin is connected to the second end of the lead wire;

[0046] The second end of the pin is connected to the cable.

[0047] Optionally, the outer wall of the connector housing is provided with an outer step, and the inner wall of the housing is provided with an inner step;

[0048] The outer step of the connector housing and the inner step of the housing are interference-fitted and are sealed by laser welding.

[0049] Optionally,

[0050] The cable is a single-layer shielded differential cable.

[0051] Compared with the prior art, the present application provides a capacitive sensor with symmetrical differential electrodes, comprising: a shell, a symmetrical differential electrode, an insulating sleeve and a cable. A receiving space with an opening is provided in the shell, the symmetrical differential electrode and the insulating sleeve are provided in the receiving space, the first end of the symmetrical differential electrode is close to the opening, the insulating sleeve is provided on the outside of the symmetrical differential electrode, and is used to insulate the symmetrical differential electrode from the shell, and the cable is connected to the second end of the symmetrical differential electrode for transmitting the differential capacitance signal sensed by the symmetrical differential electrode. In the present application, the capacitive sensor using symmetrical differential electrodes is more economical than the single electrode capacitive sensor. The differential capacitance sensor eliminates the equipotential ring structure, making the sensor structure simpler and allowing the end face area of ​​the symmetrical differential electrode to be designed to be larger within the same shell space. According to the flat-plate capacitance calculation formula, the larger the electrode end face area, the larger the capacitance value. The structure of the symmetrical differential electrode forms a differential capacitance signal with a stronger ability to resist common-mode interference during transmission, which can effectively improve the detection accuracy of the tip clearance of aircraft engines. A single-layer shielded differential cable is used for differential capacitance signal transmission. Compared with a triaxial cable, it has a simpler structure, higher reliability, and lower costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0053] Figure 1 This is a first structural schematic diagram of a capacitive sensor with symmetrical differential electrodes provided in an embodiment of the present application;

[0054] Figure 2 This is a first structural schematic diagram of another capacitive sensor with symmetrical differential electrodes provided in an embodiment of the present application;

[0055] Figure 3 A schematic diagram of a housing structure provided in an embodiment of the present application;

[0056] Figure 4 This is a schematic diagram of another housing structure provided in an embodiment of the present application;

[0057] Figure 5 A schematic diagram of capacitance distribution of a capacitive sensor with symmetrical differential electrodes provided in an embodiment of the present application;

[0058] Figure 6 This is a second structural schematic diagram of a capacitive sensor with symmetrical differential electrodes provided in an embodiment of the present application;

[0059] Figure 7 This is a second structural schematic diagram of another capacitive sensor with symmetrical differential electrodes provided in an embodiment of the present application;

[0060] Figure 8 A schematic diagram of the structure of the symmetrical differential electrode provided in the embodiment of the present application;

[0061] Figure 9 This is a schematic diagram of the front structure of a capacitive sensor with symmetrical differential electrodes provided in an embodiment of the present application;

[0062] Figure 10 This is a schematic structural diagram of the insulating sleeve provided in an embodiment of the present application;

[0063] Reference numerals: 100 - housing; 200 - symmetrical differential electrode; 300 - insulating sleeve; 400 - lead electrode; 500 - insulating sheet; 600 - lead sheet; 700 - lead wire; 710 - insulating pad; 800 - electrical connector; 900 - blade end face;

[0064] 110 - accommodating space; 111 - opening; 120 - step; 130 - mounting table; 131 - second through hole; 140 - inner step;

[0065] 210 - first electrode; 220 - second electrode; 211 - threaded hole; 212 - first chamfer;

[0066] 310-first through hole; 320-second chamfer;

[0067] 410-mounting head;

[0068] 810-connector housing; 820-pin; 811-outer step. DETAILED DESCRIPTION

[0069] In order to help those skilled in the art better understand the technical solutions in this application, the technical solutions in the embodiments of this application will be clearly and completely described below. Obviously, the embodiments described are only part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without making any creative efforts shall fall within the scope of protection of this application.

[0070] It should be noted that when an element is referred to as being “fixed on” or “set on” another element, it can be directly on the other element or indirectly set 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 indirectly connected to the other element.

[0071] It should be understood that the terms "length", "width", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on this application.

[0072] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be understood to indicate or imply relative importance or implicitly specify the number of technical features indicated. Thus, a feature specified as "first" or "second" may explicitly or implicitly include one or more of such features. Throughout the description of this application, "plurality" or "several" means two or more, unless otherwise specifically defined.

[0073] It should be noted that the structures, proportions, sizes, etc. illustrated in the drawings of this specification are only used to match the contents disclosed in the specification for people familiar with this technology to understand and read, and are not used to limit the conditions under which this application can be implemented. Therefore, they have no substantive technical significance. Any structural modification, change in proportional relationship or adjustment of size should still fall within the scope of the technical content disclosed in this application without affecting the efficacy and purpose that can be achieved by this application.

[0074] like Figures 1 to 4As shown, an embodiment of the present application provides a capacitive sensor with a symmetrical differential electrode, comprising: a shell 100, a symmetrical differential electrode 200, an insulating sleeve 300 and a cable; a accommodating space 110 with an opening 111 is provided in the shell 100; the symmetrical differential electrode 200 and the insulating sleeve 300 are arranged in the accommodating space 110, and the first end of the symmetrical differential electrode 200 is close to the opening 111; the insulating sleeve 300 is arranged on the outside of the symmetrical differential electrode 200, for insulating and isolating the symmetrical differential electrode 200 from the shell 100; the cable is connected to the second end of the symmetrical differential electrode 200, for transmitting the differential capacitance signal sensitive to the symmetrical differential electrode 200, and the first end face of the symmetrical differential electrode 200 is a precisely machined plane, serving as one pole of the flat plate capacitor.

[0075] In this embodiment, the symmetrical differential electrode 200 includes a plurality of symmetrically arranged electrodes, each electrode having the same shape. The symmetrical differential electrode 200 may include 2, 4, 6 or other electrodes.

[0076] like Figure 5 As shown, in the embodiment provided by this scheme, the symmetrical differential electrode 200 may include two electrodes: a first electrode 210 and a second electrode 220. When the blade passes through the capacitive sensor, the top of the blade is opposite to the first electrode 210 and the second electrode 220, and the blade end surface 900 and the first electrode 210 constitute a first dynamic capacitor CD1, and the blade end surface 900 and the second electrode 220 constitute a second dynamic capacitor CD2. The first electrode 210 and the second electrode 220 constitute a static capacitor CJ. The first electrode 210 and the second electrode 220 of the capacitive sensor constitute a flat plate capacitor with the facing blade end surface 900. When the facing area and distance between the blade end surface 900 and the first electrode 210 and the second electrode 220 change, the sensor capacitance will change. When measuring the engine blade tip clearance, the capacitive sensor is fixed on the casing, opposite to the blade end face 900. When the engine blade end face 900 passes through the symmetrical differential electrode 200, the plate capacitance value formed by the symmetrical differential electrode 200 of the sensor and the engine blade end face 900 will change. The dielectric constant of the medium between the blade end face 900 and the end face of the symmetrical differential electrode 200 of the sensor is The projected area of ​​the blade end face 900 on the symmetrical differential electrode 200 of the sensor is S. The relationship between the capacitance value C and the distance d between the blade end face 900 and the symmetrical differential electrode 200 and the area S is as follows:

[0077]

[0078] Where C is the capacitance value; ε is the dielectric constant of the medium; S is the projected area of ​​the blade end face on the symmetrical differential electrode; and d is the distance between the blade end face and the symmetrical differential electrode.

[0079] Compared with the prior art, the present application provides a capacitive sensor with a symmetrical differential electrode. Compared with the capacitive sensor with a single electrode structure, its electrode structure is a symmetrical differential structure, and the transmission line of the differential capacitance signal also adopts a differential structure. The common-mode interference coupled into the symmetrical differential electrode or transmission line is easier to eliminate through the subsequent differential circuit, which can effectively suppress common-mode interference and improve the measurement accuracy of the capacitive sensor.

[0080] Compared with the prior art, the present application provides a capacitive sensor with a symmetrical differential electrode, comprising: a shell 100, a symmetrical differential electrode 200, an insulating sleeve 300 and a cable. A housing space 110 with an opening 111 is provided in the shell 100. The symmetrical differential electrode 200 and the insulating sleeve 300 are arranged in the housing space 110. The first end of the symmetrical differential electrode 200 is close to the opening 111. The insulating sleeve 300 is sleeved on the outside of the symmetrical differential electrode 200 for insulating and isolating the symmetrical differential electrode 200 from the shell 100. The cable is connected to the second end of the symmetrical differential electrode 200 for transmitting the capacitance signal sensed by the symmetrical differential electrode 200. In the present application, the present invention adopts Compared with a single-electrode sensor, a capacitive sensor using symmetrical differential electrodes eliminates the equipotential ring structure, making the sensor structure simpler. In addition, within the same housing 100 space, the end face area of ​​the symmetrical differential electrode 200 can be designed to be larger. According to the flat-plate capacitance calculation formula, the larger the electrode end face area, the larger the capacitance value. The structure of the symmetrical differential electrode 200 also forms a differential capacitance signal with a stronger ability to resist common-mode interference during transmission, which can effectively improve the detection accuracy of the tip clearance of an aircraft engine. A single-layer shielded differential cable is used for differential capacitance signal transmission. Compared with a triaxial cable, the structure is simpler, the reliability is higher, and the cost is reduced.

[0081] like Figure 6 、 Figure 7 and Figure 10 As shown, as an implementation manner, in the embodiment of the present application, it also includes: a lead electrode 400; a first through hole 310 is provided on the outer wall of the first end of the insulating sleeve 300, and the first end of the lead electrode 400 passes through the first through hole 310 of the insulating sleeve 300 and is connected to the second end of the symmetrical differential electrode 200; a mounting head 410 is provided at the second end of the lead electrode 400, and the mounting head 410 is located on the side of the first through hole 310 away from the symmetrical differential electrode 200, and the second end of the lead electrode 400 is connected to the cable.

[0082] In this embodiment, the symmetrical differential electrode 200 includes two electrodes, and the number of the lead electrode 400 and the first through hole 310 can be two. By providing the lead electrode 400, the differential capacitance signal output by the symmetrical differential electrode 200 can be effectively led out to the cable.

[0083] like Figure 6 and Figure 7 As shown, as an implementation manner, in the embodiment of the present application, it also includes: a lead-in plate 600 and a lead-in wire 700; the lead-in plate 600 is connected to the second end of the lead-in electrode 400, and the first end of the lead-in wire 700 is connected to the lead-in plate 600 by laser welding or resistance welding; the second end of the lead-in wire 700 is connected to the cable.

[0084] In this embodiment, the symmetrical differential electrode 200 includes two electrodes, the number of the lead-in plates 600 can be two, and the number of the lead-in wires 700 can be two. By setting the lead-in plates 600 and the lead-in wires 700, the differential capacitance signal transmitted by the lead electrode 400 can be effectively led out to the cable.

[0085] like Figure 3 and Figure 6 As shown, as an implementation manner, in the embodiment of the present application, a step 120 is provided in the shell 100; the outer wall of the first end of the insulating sleeve 300 abuts against the step 120 in the shell 100.

[0086] In this embodiment, the outer wall of the first end of the insulating sleeve 300 is brought into contact with the step 120 in the housing 100 , thereby effectively preventing the insulating sleeve 300 from moving.

[0087] like Figure 4 、 Figure 7 and Figure 10 As shown, as an implementation mode, in the embodiment of the present application, a mounting table 130 is provided in the shell 100, and a second through hole 131 corresponding to the position of the first through hole 310 is provided on the mounting table 130; the outer wall of the first end of the insulating sleeve 300 abuts against the first end surface of the mounting table 130; the first end of the lead electrode 400 passes through the second through hole 131 of the mounting table 130 and the first through hole 310 of the insulating sleeve 300, and is connected to the second end of the symmetrical differential electrode 200; the mounting head 410 at the second end of the lead electrode 400 limits and fixes the lead electrode 400 to the second end surface of the mounting table 130; an insulating pad 710 is provided between the lead plate 600 and the second end surface of the mounting table 130, and the insulating pad 710 is used to insulate and isolate the lead plate 600 from the shell 100.

[0088] In this embodiment, the number of second through holes 131 can be 2. By setting a mounting table 130 in the shell 100 and making the outer wall of the first end of the insulating sleeve 300 abut against the first end surface of the mounting table 130, the insulating sleeve 300 can be effectively prevented from moving; the first end of the lead electrode 400 passes through the second through hole 131 of the mounting table 130 and the first through hole 310 of the insulating sleeve 300, and is connected to the second end of the symmetrical differential electrode 200, so that the symmetrical differential electrode 200 can be fixed in the accommodating space 110 in the insulating sleeve 300; the mounting head 410 set at the second end of the lead electrode 400 can limit and fix the lead electrode 400 to the second end surface of the mounting table 130; by setting an insulating pad 710 between the lead plate 600 and the second end surface of the mounting table 130, the lead plate 600 can be effectively insulated and isolated from the shell 100.

[0089] like Figure 8 and 10 As shown, as an implementation mode, in the embodiment of the present application, the second end outer wall of the symmetrical differential electrode 200 abuts against the first end inner wall of the insulating sleeve 300; the second end outer wall of the symmetrical differential electrode 200 is provided with a first chamfer 212; the first end outer wall of the insulating sleeve 300 is provided with a second chamfer 320.

[0090] In this embodiment, chamfers are provided on the outer wall of the second end of the symmetrical differential electrode 200 and the outer wall of the first end of the insulating sleeve 300 , thereby facilitating assembly of the symmetrical differential electrode 200 and the insulating sleeve 300 .

[0091] like Figure 3 、 Figure 4 、 Figure 6 and Figure 7 As shown, as an embodiment, in the embodiment of the present application, the symmetrical differential electrode 200 includes a first electrode 210 and a second electrode 220, and the number of the lead electrode 400, the lead plate 600, and the lead wire 700 are respectively 2; the first end of the first lead electrode 400 is connected to the second end of the first electrode 210, and the first end of the second lead electrode 400 is connected to the second end of the second electrode 220; the second end of the first lead electrode 400 is connected to the first lead wire 700 through the first lead plate 600, and the second end of the second lead electrode 400 is connected to the second lead wire 700 through the second lead plate 600.

[0092] like Figure 3 、 Figure 6 and Figure 10As shown, in this embodiment, the number of first through holes 310 is 2, and the first end of the first lead electrode 400 can be connected to the second end of the first electrode 210 through the first first through hole 310, the first end of the second lead electrode 400 is connected to the second end of the second electrode 220 through the second first through hole 310, the second end of the first lead electrode 400 is connected to the first end of the first lead wire 700 through the first lead sheet 600, the second end of the second lead electrode 400 is connected to the first end of the second lead wire 700 through the second lead sheet 600, and the second ends of the two lead wires 700 are connected to the cable.

[0093] like Figure 4 、 Figure 7 and Figure 10 As shown, the number of the first through holes 310 and the number of the second through holes 131 are both 2. The first end of the first lead electrode 400 can be connected to the second end of the first electrode 210 through the first first through hole 310 and the first second through hole 131, the first end of the second lead electrode 400 is connected to the second end of the second electrode 220 through the second first through hole 310 and the second second through hole 131, the second end of the first lead electrode 400 is connected to the first end of the first lead wire 700 through the first lead sheet 600, the second end of the second lead electrode 400 is connected to the first end of the second lead wire 700 through the second lead sheet 600, and the second ends of the two lead wires 700 are connected to the cable.

[0094] In this embodiment, the symmetrical differential electrode 200 may include four electrodes, that is, there may be two first electrodes 210 and two second electrodes 220. The number of lead electrodes 400, lead sheets 600, and lead wires 700 may be four respectively, and may be divided into two groups of two in each group. The first group may include two first electrodes 210, two lead electrodes 400, two lead sheets 600, two lead wires 700, and two first through holes 310. The second group may include two second electrodes 220, two lead electrodes 400, two lead sheets 600, two lead wires 700, and two first through holes 310. Specifically, the first end of the first lead electrode 400 may be connected to the second end of the first first electrode 210, the second end of the first lead electrode 400 may be connected to the first end of the first lead wire 700 through the first lead sheet 600, and the second lead The first end of the electrode 400 is connected to the second end of the second first electrode 210, the second end of the second lead electrode 400 is connected to the first end of the second lead wire 700 through the second lead sheet 600, the second end of the first lead wire 700 and the second end of the second lead wire 700 are connected in parallel and then connected to the cable, the first end of the third lead electrode 400 can be connected to the second end of the first second electrode 220, the second end of the third lead electrode 400 is connected to the first end of the third lead wire 700 through the third lead sheet 600, the first end of the fourth lead electrode 400 is connected to the second end of the second second electrode 220, the second end of the fourth lead electrode 400 is connected to the first end of the fourth lead wire 700 through the fourth lead sheet 600, the second end of the third lead wire 700 and the second end of the fourth lead wire 700 are connected in parallel and then connected to the cable.

[0095] like Figure 6 、 Figure 7 and Figure 9 As shown, as an implementation manner, in the embodiment of the present application, an insulating sheet 500 is provided between the symmetric planes of the first electrode 210 and the second electrode 220 , and the insulating sheet 500 is used to insulate and isolate the first electrode 210 and the second electrode 220 .

[0096] In this embodiment, the first electrode 210 and the second electrode 220 are semi-cylindrical in shape. By setting an insulating sheet 500 between the symmetrical planes of the first electrode 210 and the second electrode 220, the first electrode 210 and the second electrode 220 can be effectively insulated and isolated from each other, and the first electrode 210 and the second electrode 220 can be effectively prevented from contacting each other and causing a short circuit.

[0097] As an implementation manner, in the embodiment of the present application, the joints of the insulating sheet 500 , the first electrode 210 , the second electrode 220 , the insulating sleeve 300 and the shell 100 are all provided with metallized connecting edges, which are sealed by welding.

[0098] In this embodiment, metallized connecting edges are provided at the joints between the insulating sheet 500 and the first electrode 210 and the second electrode 220, at the joints between the first electrode 210 and the second electrode 220 and the insulating sleeve 300, and at the joints between the insulating sleeve 300 and the shell 100. Sealing is achieved by welding, which can achieve a better sealing effect.

[0099] As an implementation mode, in the embodiment of the present application, the first electrode 210 and the second electrode 220 are made of high-temperature resistant metal or alloy; the insulating sleeve 300 and the insulating sheet 500 are made of one or more of high-temperature resistant alumina ceramics, polyimide, and polytetrafluoroethylene.

[0100] In this embodiment, the first electrode 210 and the second electrode 220 may be made of high-temperature resistant platinum.

[0101] As an implementation manner, in the embodiment of the present application, the insulating sleeve 300 is connected to the housing 100 by vacuum brazing, hydrogen or inert gas shielded welding to prevent the symmetrical differential electrode 200 from falling out.

[0102] In this embodiment, the insulating sleeve 300 and the housing 100 are connected by vacuum brazing, or by hydrogen or inert gas shielded welding, which can effectively prevent the first electrode 210 and the second electrode 220 in the insulating sleeve 300 from falling out.

[0103] like Figure 6 、 Figure 8 As shown, as an implementation mode, in an embodiment of the present application, the second end of the symmetrical differential electrode 200 is provided with a threaded hole 211, and the first end of the lead electrode 400 is provided with an external thread; the first end of the lead electrode 400 passes through the first through hole 310 of the insulating sleeve 300 and is connected with the threaded hole 211 of the second end of the symmetrical differential electrode 200, and the second end of the lead electrode 400 is provided with a mounting head 410, which limits and fixes the lead electrode 400 to the insulating sleeve 300.

[0104] In this embodiment, the second ends of the first electrode 210 and the second electrode 220 may be provided with threaded holes, and the number of the lead electrode 400 and the first through hole 310 is 2. The first end of the first lead electrode 400 passes through the first first through hole 310 of the insulating sleeve 300 and is connected to the threaded hole 211 at the second end of the first electrode 210. The first end of the second lead electrode 400 passes through the second first through hole 310 of the insulating sleeve 300 and is connected to the threaded hole 211 at the second end of the second electrode 220. By setting the connection mode between the lead electrode 400 and the first electrode 210 and the second electrode 220 to be a threaded connection, subsequent disassembly as needed is facilitated. By fixing the lead electrode 400 to the first electrode 210 and the second electrode 220 in a threaded manner, and by using the mounting head 410 at the second end of the lead electrode 400, the lead electrode 400 can be effectively limited and fixed to the insulating sleeve 300.

[0105] like Figure 7 、 Figure 8 As shown, as an implementation mode, in an embodiment of the present application, the second end of the symmetrical differential electrode 200 is provided with a threaded hole 211, and the first end of the lead electrode 400 is provided with an external thread; the first end of the lead electrode 400 passes through the second through hole 131 of the mounting table 130, the first through hole 310 of the insulating sleeve 300 and is connected with the threaded hole 211 of the second end of the symmetrical differential electrode 200, and the second end of the lead electrode 400 is provided with a mounting head 410, which limits and fixes the lead electrode 400 to the shell 100.

[0106] In this embodiment, the second ends of the first electrode 210 and the second electrode 220 may be provided with threaded holes, and the number of the lead electrode 400, the first through hole 310, and the second through hole 131 is two. The first end of the first lead electrode 400 passes through the first second through hole 131 of the mounting table 130, the first first through hole 310 of the insulating sleeve 300, and is connected to the threaded hole 211 at the second end of the first electrode 210. The first end of the second lead electrode 400 passes through the second second through hole 131 of the mounting table 130, the second first through hole 310 of the insulating sleeve 300, and is connected to the threaded hole 211 at the second end of the second electrode 220. By setting the connection between the lead electrode 400 and the first electrode 210 and the second electrode 220 as a threaded connection, subsequent disassembly as needed is facilitated. By fixing the lead electrode 400 to the first electrode 210 and the second electrode 220 in a threaded manner and by using the mounting head 410 at the second end of the lead electrode 400, the lead electrode 400 can be effectively fixed to the housing 100.

[0107] As an implementation manner, in the embodiment of the present application, the lead electrode 400 is a screw.

[0108] In this embodiment, the lead electrode 400 may be a screw made of high-temperature metal or alloy, which is convenient for fixation and electricity conduction.

[0109] like Figure 6 and Figure 7 As shown, as an implementation manner, in the embodiment of the present application, it also includes: an electrical connector 800, the electrical connector 800 includes a connector housing 810 and a pin 820; the connector housing 810 is fixedly connected to the housing 100 and the pin 820; the first end of the pin 820 is connected to the second end of the lead wire 700; the second end of the pin 820 is connected to the cable.

[0110] In this embodiment, there may be two pins 820 , and an external thread is provided on the outer wall of the connector housing 810 . By providing the pins 820 , the differential capacitance signal transmitted by the lead wire 700 can be effectively led out to the cable.

[0111] like Figure 3 、 Figure 4 、 Figure 6 and Figure 7 As shown, as an implementation method, in the embodiment of the present application, the outer wall of the connector housing 810 is provided with an outer step 811, and the inner wall of the housing 100 is provided with an inner step 140; the outer step 811 of the connector housing 810 and the inner step 140 of the housing 100 are interference fit and are sealed by laser welding.

[0112] In this embodiment, the outer step 811 of the connector housing 810 and the inner step 140 of the housing 100 are interference fit and sealed by laser welding, which can improve the fixing effect and sealing effect between the connector housing 810 and the housing 100.

[0113] As an implementation manner, in the embodiment of the present application, the cable is a single-layer shielded differential cable.

[0114] In this embodiment, the single-layer shielded differential cable has a simpler structure, higher reliability, and lower cost compared to the triaxial cable.

[0115] The embodiments in this specification are described in a progressive manner, and each embodiment focuses on the following

[0116] For other differences between the embodiments, reference may be made to the same or similar parts between the embodiments.

[0117] The above description of the disclosed embodiments is intended to enable one skilled in the art to implement or use the present application. Various modifications to these embodiments will be readily apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application is not limited to the embodiments shown herein, but is intended to conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A capacitive sensor with symmetrical differential electrodes, characterized in that: include: Housing, symmetrical differential electrodes, insulating sleeve and cable; An accommodating space with an opening is provided in the shell; The symmetrical differential electrode and the insulating sleeve are arranged in the accommodating space, and the first end of the symmetrical differential electrode is close to the opening; The insulating sleeve is arranged on the outside of the symmetrical differential electrode and is used to insulate and isolate the symmetrical differential electrode from the shell; The cable is connected to the second end of the symmetrical differential electrode and is used to transmit the differential capacitance signal sensed by the symmetrical differential electrode.

2. The capacitive sensor according to claim 1, wherein Also included: a lead electrode; A first through hole is provided on the outer wall of the first end of the insulating sleeve, and the first end of the lead electrode passes through the first through hole of the insulating sleeve and is connected to the second end of the symmetrical differential electrode; The second end of the lead electrode is provided with a mounting head, and the mounting head is located on a side of the first through hole away from the symmetrical differential electrode. The second end of the lead electrode is connected to the cable.

3. The capacitive sensor according to claim 2, wherein: It also includes a lead-in plate and a lead-in wire, wherein the lead-in plate is connected to the second end of the lead-in electrode, the first end of the lead-in wire is connected to the lead-in plate by laser welding or resistance welding, and the second end of the lead-in wire is connected to the cable.

4. The capacitive sensor according to claim 3, wherein: A step is provided in the shell; The outer wall of the first end of the insulating sleeve abuts against the step in the shell.

5. The capacitive sensor according to claim 3, wherein: A mounting table is provided in the housing, and a second through hole is provided on the mounting table corresponding to the position of the first through hole; the outer wall of the first end of the insulating sleeve abuts against the first end surface of the mounting table; The first end of the lead electrode passes through the second through hole of the mounting table and the first through hole of the insulating sleeve, and is connected to the second end of the symmetrical differential electrode; The mounting head at the second end of the lead electrode is used to fix the lead electrode limit position to the second end surface of the mounting table; An insulating pad is provided between the current lead plate and the second end surface of the mounting table, and the insulating pad is used to insulate and isolate the current lead plate from the shell.

6. The capacitive sensor according to claim 4 or 5, characterized in that: The outer wall of the second end of the symmetrical differential electrode abuts against the inner wall of the first end of the insulating sleeve; The outer wall of the second end of the symmetrical differential electrode is provided with a first chamfer; The outer wall of the first end of the insulating sleeve is provided with a second chamfer.

7. The capacitive sensor according to claim 3, characterized in that: The symmetrical differential electrode includes a first electrode and a second electrode, and the number of the lead electrode, the lead sheet, and the lead wire are respectively 2; The first end of the first lead electrode is connected to the second end of the first electrode, and the first end of the second lead electrode is connected to the second end of the second electrode; The second end of the first lead electrode is connected to the first lead wire through the first lead sheet, and the second end of the second lead electrode is connected to the second lead wire through the second lead sheet.

8. The capacitive sensor according to claim 7, characterized in that An insulating sheet is provided between the symmetric planes of the first electrode and the second electrode, and the insulating sheet is used to insulate and isolate the first electrode from the second electrode.

9. The capacitive sensor according to claim 8, characterized in that The joints between the insulating sheet, the first electrode, the second electrode, the insulating sleeve and the shell are all provided with metallized connecting edges, which are sealed by welding.

10. The capacitive sensor according to claim 9, characterized in that The first electrode and the second electrode are made of high temperature resistant metal or alloy; The insulating sleeve and the insulating sheet are made of one or more of high-temperature resistant alumina ceramics, polyimide, and polytetrafluoroethylene.

11. The capacitive sensor according to claim 1, wherein The insulating sleeve is connected to the shell by vacuum brazing, hydrogen or inert gas shielded welding to prevent the symmetrical differential electrode from falling out.

12. The capacitive sensor according to claim 2, wherein: The second end of the symmetrical differential electrode is provided with a threaded hole, and the first end of the lead electrode is provided with an external thread; The first end of the lead electrode passes through the first through hole of the insulating sleeve and is connected to the threaded hole of the second end of the symmetrical differential electrode; The mounting head fixes the electrical limiter to the insulating sleeve.

13. The capacitive sensor according to claim 12, wherein: The lead electrode is a screw.

14. The capacitive sensor according to claim 4 or 5, characterized in that: Also includes: An electrical connector comprising a connector housing and pins; The connector housing is fixedly connected to the housing and the pin; The first end of the pin is connected to the second end of the lead wire; The second end of the pin is connected to the cable.

15. The capacitive sensor according to claim 14, wherein: The outer wall of the connector housing is provided with an outer step, and the inner wall of the housing is provided with an inner step; The outer step of the connector housing and the inner step of the housing are interference-fitted and are sealed by laser welding.

16. The capacitive sensor according to claim 1, wherein The cable is a single-layer shielded differential cable.

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