Round-tube-shaped vibration electrode for electrostatic detection

Abstract

The utility model discloses a circular-tube-shaped vibration electrode for electrostatic detection, and belongs to the field of electrostatic measurement. The vibration electrode with the circular tube-shaped structure comprises a circular tube-shaped fixed electrode, a circular ring-shaped piezoelectric ceramic piece and a circular tube-shaped vibration electrode, the circular-ring-shaped piezoelectric ceramic piece is located between the circular-tube-shaped fixed electrode and the circular-tube-shaped vibration electrode, the circular-ring-shaped piezoelectric ceramic piece completely covers the end face of the vibration electrode, and the circular-tube-shaped fixed electrode, the circular-ring-shaped piezoelectric ceramic piece and the circular-tube-shaped vibration electrode are coaxially arranged and fixedly connected into a whole in sequence. The whole static voltage sensor is located in the static voltage sensor shell; the circular-tube-shaped fixed electrode is fixed on the circuit board, a cylindrical electrostatic charge induction electrode is arranged in front of the circular-tube-shaped vibration electrode, and the central axes of the circular-tube-shaped fixed electrode and the cylindrical electrostatic charge induction electrode coincide; one end of the cylindrical electrostatic charge induction electrode faces the circular tube-shaped vibration electrode, and the other end faces the static power supply; the circular tube-shaped fixed electrode is electrically connected with the circuit board; and the circular tube-shaped vibration electrode is connected with zero volt voltage.

Description

Technical Field

[0001] The utility model belongs to the field of charge and electrical quantity measuring devices, and in particular relates to a vibration detection electrode for detecting static voltage on the surface of an object. Background Art

[0002] The electrostatic voltage sensor is a professional and key instrument for detecting static charge on the surface of objects. The accuracy and stability of its detection data play a very important role in the electrostatic protection of electrostatic sensitive devices.

[0003] At present, most of the mainstream electrostatic voltage sensors on the market adopt non-contact detection methods. They use the principle of electrostatic induction to bring the vibrating capacitive test probe close to the charged body, and use the distorted electric field generated between the probe and the charged body to test the surface potential of the charged body. In essence, it is a test of the electric field on the surface of the charged body.

[0004] Since this test does not directly contact the charged body, it is also called non-contact measurement, and the electrostatic voltage sensor used is also called non-contact electrostatic voltage sensor.

[0005] Compared with contact measurement, non-contact measurement results are less affected by the instrument input capacitance and input resistance, and its measurement accuracy is closely related to the mechanical / electrical structure of the vibrating electrode in the electrostatic induction sensor.

[0006] Therefore, continuously optimizing the electrical structure design of the vibrating electrode is of great significance to the detection performance of the non-contact electrostatic voltage sensor.

[0007] The typical structure of the existing vibration electrode can be found in the two patents previously applied by the applicant: the invention patent "A portable electrostatic detection device and electrostatic detection method thereof" with the authorization announcement date of 2013.11.13 and the authorization announcement number of CN 102353855 B, and the utility model patent "An electrostatic sensor detection head" with the authorization announcement date of 2019.10.11 and the authorization announcement number of CN 209486193U; the specific structure of the vibration electrode is as follows: Figure 1 , Figure 2a to Figure 2e As shown in FIG. 1 , a sensor bracket and a charge sensing sheet are arranged on the circuit board f. The cross section of the sensor bracket is a gate-shaped structure, which is composed of two longitudinal vertical sides of the sensor bracket and the top horizontal side of the sensor bracket; the charge sensing sheet is arranged vertically to the circuit board.

[0008] In this technical solution, two vibration plates d are symmetrically arranged and connected together through a special-shaped connecting plate a located at the rear; the two vibration plates are fixed above the circuit board through the four supporting plates b at the rear, and through the welding feet b' at the bottom of the supporting plates, a "point" fixed structure is formed and fixedly welded on the circuit board. Two piezoelectric ceramic plates c are located in front of the special-shaped connecting plate and are symmetrically arranged on the inner surface of the two vibration plates; the two piezoelectric ceramic plates are electrically connected to the circuit board f through the lead wire c'; the static charge sensing electrode e is independently arranged at the front end of the vibration plate. It uses piezoelectric ceramics to make the two longitudinal vertical edges of the sensor bracket produce lateral vibrations, forming an action mode similar to the vibration of a tuning fork, and the charge sensing plate is used to receive the action signal generated by the external static charge. It can effectively prevent the interference of the outside world on the electrostatic sensing signal; fundamentally solve the problem of quantitative detection of static electricity, and the subsequent amplification / processing of the monitoring data is easy, the repeatability of the detection data is good, and the accuracy and stability of static detection are improved; it helps to ensure the product qualification rate of the electrostatic sensor.

[0009] However, in actual use, it is found that the existing technical solutions have the following technical defects:

[0010] 1) The fixing method of the vibration electrode is "point" fixing (also known as "point" fixing method), which is not conducive to regular vibration in the functional vibration direction (also known as the main vibration direction), and will form interfering vibrations in other directions, forming stray capacitance signals between the static charge sensing electrode, causing distortion of the functional detection signal, and failing to form a standard sinusoidal wave signal on the static charge sensing electrode, which is not conducive to the detection result;

[0011] 2) The functional vibration direction of the vibrating plate (also called the main vibration direction, referred to as the functional (main) vibration direction) is perpendicular to the length direction of the vibrating plate, that is, a transverse wave vibration is formed (see Figure 2-1 , Figure 2-2 As shown in , the vibration electrode cannot quickly reach a stable vibration state, and because the piezoelectric ceramic sheet only covers a small area of ​​the vibration plate, this structural mode setting is not conducive to the vibration electrode quickly forming a stable vibration state, resulting in poor stability of the detection signal.

[0012] How to reduce the interfering vibration of the vibrating electrode and the stray capacitance signal caused by it, so that the detection results of the non-contact electrostatic voltage sensor are more accurate and more stable, is a practical technical problem that needs to be solved urgently in actual research and development work. Utility Model Content

[0013] The technical problem to be solved by the utility model is to provide a circular tubular vibration electrode for electrostatic detection. The fixing method of the vibration electrode is changed from a "point" fixing method to a "circular ring" fixing method; its functional (main) vibration direction is parallel to the length direction (axial direction) of the vibration electrode, forming a longitudinal wave / longitudinal vibration mode, and the circular piezoelectric ceramic piece fully covers the tail section of the vibration electrode; in this way, interfering vibrations and the stray capacitance signals caused by them can be effectively reduced, making the detection results more accurate and more stable.

[0014] The technical solution of the utility model is to provide a circular tubular vibrating electrode for electrostatic detection, including a vibrating electrode for electrostatic detection, which is characterized by:

[0015] The vibrating electrode is a vibrating electrode with a circular tubular structure;

[0016] The vibrating electrode of the circular tubular structure comprises a circular tubular fixed electrode, a circular annular piezoelectric ceramic piece and a circular tubular vibrating electrode; the circular tubular fixed electrode, the circular annular piezoelectric ceramic piece and the circular tubular vibrating electrode are arranged coaxially, and the three are fixedly connected in sequence as a whole, and the whole is located inside the static voltage sensor housing; the circular tubular fixed electrode is fixed on the circuit board, and the circular annular piezoelectric ceramic piece is located between the circular tubular fixed electrode and the circular tubular vibrating electrode; the circular annular piezoelectric ceramic piece completely covers the end surface of the vibrating electrode.

[0017] A cylindrical electrostatic charge induction electrode is arranged in front of the cylindrical vibrating electrode; the central axes of the cylindrical electrostatic charge induction electrode and the cylindrical vibrating electrode are arranged to coincide with each other; one end of the cylindrical electrostatic charge induction electrode faces the cylindrical vibrating electrode; and the other end of the cylindrical electrostatic charge induction electrode faces the electrostatic source;

[0018] The circular tubular fixed electrode is electrically connected to the circuit board; the circular tubular vibrating electrode is connected to a zero volt voltage.

[0019] Specifically, the circular tubular fixed electrode is a metallic circular tubular fixed electrode; and the circular tubular vibrating electrode is a metallic circular tubular vibrating electrode.

[0020] Furthermore, a ceramic sleeve is mounted on the cylindrical electrostatic charge induction electrode; the length of the cylindrical electrostatic charge induction electrode is greater than the length of the ceramic sleeve; and the cylindrical electrostatic charge induction electrode is partially mounted in the ceramic sleeve along its length direction.

[0021] Furthermore, the portion of the cylindrical electrostatic charge sensing electrode that exceeds the length of the ceramic sleeve is arranged toward the electrostatic source; the portion of the cylindrical electrostatic charge sensing electrode that exceeds the length of the ceramic sleeve is arranged outside the electrostatic voltage sensor housing.

[0022] Furthermore, the central axis of the cylindrical electrostatic charge induction electrode and the ceramic sleeve coincides with the central axis of the tubular vibration electrode; the cylindrical electrostatic charge induction electrode and the ceramic sleeve are arranged in front of the tubular vibration electrode.

[0023] Specifically, the annular piezoelectric ceramic piece completely covers the end surface of the cylindrical vibrating electrode, so that the cylindrical vibrating electrode only generates overall vibration / movement along the longitudinal axis of the vibrating electrode; the mechanical vibration frequency of the cylindrical vibrating electrode is consistent with the driving voltage frequency of the annular piezoelectric ceramic piece.

[0024] Furthermore, the functional vibration direction / main vibration direction of the circular tubular vibration electrode is parallel to or coincides with the length direction of the circular tubular vibration electrode, forming a longitudinal wave vibration mode.

[0025] Specifically, the circular tubular fixed electrode is fixed to the circuit board through one end surface of the circular tubular fixed electrode; the circular tubular fixed electrode and the circuit board are fixedly connected as one body by adopting a "surface contact" fixing structure.

[0026] Furthermore, the other end of the cylindrical electrostatic charge sensing electrode extends out of the housing of the electrostatic voltage sensor and faces the electrostatic power source.

[0027] Specifically, a sinusoidal voltage is electrically connected to the cylindrical fixed electrode through a circuit board; the cylindrical vibrating electrode is connected to a zero volt voltage; in this way, the annular piezoelectric ceramic sheet located between the cylindrical fixed electrode and the cylindrical vibrating electrode is driven to cause the cylindrical vibrating electrode to generate an overall vibration / reciprocating motion along the longitudinal axis of the cylindrical vibrating electrode, forming a longitudinal wave vibration, and finally forming a standard sinusoidal oscillation capacitor between the cylindrical vibrating electrode and the cylindrical electrostatic charge induction electrode, and forming a standard sinusoidal signal on the cylindrical electrostatic charge induction electrode.

[0028] Compared with the prior art, the advantages of the utility model are:

[0029] 1. The circular tubular vibrating electrode of the technical solution changes the "point" fixing method of the prior art to a circular ring-shaped "surface" fixing method (also called "circular ring surface" fixing method), strengthens the constraint on the vibrating electrode, and combines the circular tubular structure to greatly reduce the interfering vibration in the non-functional (main) vibration direction during the vibration process, effectively suppresses the generation of stray capacitance signals, and improves the accuracy of the detection results;

[0030] 2. The functional (main) vibration direction of the circular tubular vibration electrode of the technical solution is parallel to the axial direction of the vibration electrode, forming a longitudinal wave vibration, and the piezoelectric ceramic piece fully covers the extreme vibration end surface, so that the vibration electrode will quickly reach a stable vibration state and enhance the stability of the detection signal;

[0031] 3. The circular tubular vibrating electrode of the technical solution has a faster startup response speed, thus saving the time of startup preheating and debugging of the static voltage sensor;

[0032] 4. The circular tubular vibrating electrode of the present technical solution has a circular piezoelectric ceramic sheet that fully covers the end surface of the vibrating electrode. Due to its own structural reasons, the vibrating electrode has almost no local deformation compared to the vibrating sheet of the vibrating electrode in the prior art, and only generates overall vibration / motion of the vibrating electrode (compare Figure 2-1 , 2-2 and Figure 5 , Figure 6 ); its mechanical vibration frequency is consistent with its driving voltage frequency, that is, the vibration frequency is completely controlled by the driving voltage frequency. In this way, the driving voltage frequency can be adjusted according to the change of the static power source, so that the vibration frequency can better adapt to the field process changes and enhance the applicability to the field environment;

[0033] 5. The circular tubular vibrating electrode of the present technical solution is an axisymmetric structure with a simple structure, which reduces the difficulty and cost of manufacturing and can more easily achieve high-precision requirements. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 It is a structural schematic diagram of an existing electrostatic detection electrode;

[0035] Figure 2a It is a schematic diagram of the unfolded planar structure of an existing electrostatic detection electrode;

[0036] Figure 2b A schematic diagram of the side view structure of an existing electrostatic detection electrode;

[0037] Figure 2c and Figure 2d It is a schematic diagram of the left and right view structure of the existing electrostatic detection electrode;

[0038] Figure 2e It is a schematic diagram of the top view structure of the existing electrostatic detection electrode;

[0039] Figure 2-1 A schematic diagram of the simulation of the vibration / movement mode of the existing electrostatic detection electrode;

[0040] Figure 2-2 It is another simulation schematic diagram of the vibration / movement mode of the existing electrostatic detection electrode;

[0041] Figure 3 This is a schematic diagram of the three-dimensional structure of the electrostatic detection electrode of this technical solution;

[0042] Figure 3-1 This is another three-dimensional structural schematic diagram of the electrostatic detection electrode of this technical solution;

[0043] Figure 3-2 This is a front view of the electrostatic detection electrode of this technical solution;

[0044] Figure 3-3 This is a top view of the electrostatic detection electrode of this technical solution;

[0045] Figure 3-4 This is a bottom view of the electrostatic detection electrode of this technical solution;

[0046] Figure 3-5 This is a cross-sectional view of the electrostatic detection electrode of this technical solution;

[0047] Figure 4 This is a flowchart of the simulation comparison test of the electrostatic detection electrode structure of this technical solution;

[0048] Figure 5 This is a simulation diagram of the vibration / movement mode of the electrostatic detection electrode of this technical solution;

[0049] Figure 6 This is another simulation diagram of the vibration / movement mode of the electrostatic detection electrode of the technical solution;

[0050] Figure 7 is the X-component diagram of the interference displacement of the existing electrostatic detection electrode;

[0051] Figure 8 It is the functional (main) displacement Y component diagram of the existing electrostatic detection electrode;

[0052] Fig. 9 is a diagram of the interfering displacement Z component of the existing electrostatic detection electrode;

[0053] Fig.10 This is the X-component diagram of the interference displacement of the electrostatic detection electrode of this technical solution

[0054] Fig.11 This is the Y component diagram of the interfering displacement of the electrostatic detection electrode of this technical solution

[0055] Fig.12 This is the functional (main) displacement Z component diagram of the electrostatic detection electrode of this technical solution

[0056] Fig.13 This is a comparison diagram of the functional (main) displacement of the present technical solution and the existing electrostatic detection electrode;

[0057] Figure 13-1 Comparison diagram of the displacement vibration waveform and driving voltage waveform of the technical solution and the existing electrostatic detection electrode function (main);

[0058] Fig.14 This is a comparison diagram of the interference displacement between this technical solution and the existing electrostatic detection electrode.

[0059] Figure 1 to Figure 2e In the figure: a is a special-shaped connecting piece, b is a supporting piece, b′ is a welding foot, c is a piezoelectric ceramic piece, c′ is a lead, d is a vibrating piece, e is an electrostatic charge sensing electrode, and f is a circuit board; o is a displacement analysis point selected in the prior art solution;

[0060] Figures 3 to 14 In the figure, 1 is a fixed electrode, 1-1 is a tail end face of the fixed electrode, 2 is a vibration electrode, 3 is a circular piezoelectric ceramic piece, 4 is an electrostatic charge sensing electrode, 4-1 is a sensing surface / detection surface of the electrostatic charge sensing electrode, 5 is a ceramic sleeve, and o' is a displacement analysis selection point of the technical solution;

[0061] h1 is the outer diameter of the static detection electrode, h2 is the inner diameter of the static detection electrode, and h3 is the thickness of the annular piezoelectric ceramic piece. DETAILED DESCRIPTION

[0062] The utility model is further described below in conjunction with the accompanying drawings and embodiments.

[0063] 1. This technical solution is achieved by adopting the following structure:

[0064] A circular tubular vibration electrode is provided, which comprises three parts: a metallic circular tubular fixed electrode 1 , a circular piezoelectric ceramic piece 3 , and a metallic circular tubular vibration electrode 2 .

[0065] The fixed electrode is fixedly welded on the circuit board, the annular piezoelectric ceramic piece is located between the fixed electrode and the vibration electrode, and the three are bonded or fixedly connected as a whole by conductive glue.

[0066] The size of the circular tubular vibrating electrode, especially the size of the inner and outer diameters and the thickness of the circular piezoelectric ceramic piece, can be set according to the needs of electrostatic detection.

[0067] A cylindrical electrostatic charge induction electrode 4 is arranged in front of the cylindrical vibrating electrode, and the central axes of the two coincide with each other; one end of the cylindrical electrostatic charge induction electrode (referred to as the electrostatic charge induction electrode sensing surface / detection surface 4-1) faces the electrostatic source.

[0068] The relative position (also called relative spacing) of the cylindrical electrostatic charge sensing electrode and the cylindrical vibrating electrode can be adjusted on the central axis according to detection requirements.

[0069] The diameter and length of the cylindrical electrostatic charge sensing electrode can be set according to detection requirements.

[0070] Furthermore, the cylindrical electrostatic charge induction electrode is sleeved in a ceramic sleeve 5, and the leaked portion of the cylindrical electrostatic charge induction electrode faces the electrostatic source; the central axis of the two coincides with the central axis of the tubular vibrating electrode, and the two are located in front of the tubular vibrating electrode. Similarly, the relative position or relative spacing with the tubular vibrating electrode can be adjusted on the central axis according to detection needs.

[0071] The cylindrical electrostatic charge induction electrode may be close to or in contact with the electrostatic source, and the function of the ceramic sleeve is to prevent the cylindrical electrostatic charge induction electrode from discharging to the vibrating electrode after inducing a large amount of electrostatic charge, thereby damaging / damaging the vibrating electrode.

[0072] A sinusoidal voltage is applied to the cylindrical fixed electrode, and the cylindrical vibrating electrode is connected to a zero volt voltage to drive the annular piezoelectric ceramic piece in the middle to generate a reciprocating motion (i.e., forming a longitudinal wave vibration) in the length direction (axial / detection direction, i.e., the direction of the central axis where the sensing surface (detection surface) of the cylindrical electrostatic charge sensing electrode is located). Ultimately, a standard sinusoidal oscillation capacitance is formed between the cylindrical vibrating electrode and the cylindrical electrostatic charge sensing electrode, and a standard sinusoidal signal is formed on the cylindrical electrostatic charge sensing electrode.

[0073] In this technical solution, since the annular piezoelectric ceramic sheet 3 completely covers the end surface of the vibration electrode 2, and due to its own structural reasons, compared with the existing vibration electrode vibration sheet, the vibration electrode in this technical solution hardly produces its own local deformation, but only produces the overall vibration / motion of the vibration electrode (compared to Figure 2-1 , 2-2 and Figure 5 , Figure 6 shown in; Figure 2-1 , Figure 2-2 In the prior art, a piezoelectric ceramic sheet is partially arranged on the inner surface of the vibrating electrode vibrating sheet, and the vibration / movement of the vibrating sheet occurs at the end of the vibrating sheet close to one end of the electrostatic charge induction electrode, and the vibration process is similar to the front end "vibration" mode of a tuning fork (also known as a transverse wave vibration mode), that is, the aforementioned vibrating electrode sheet produces its own local deformation; and, due to the influence of factors such as its material and structural shape, the mechanical vibration frequency of the front end of the vibrating electrode sheet cannot be completely consistent with the driving voltage frequency of the piezoelectric ceramic sheet; and from Figure 5 , Figure 6 It can be seen from the figure that the circular tubular vibrating electrode of the present technical solution, because the annular piezoelectric ceramic piece fully covers the end surface of the vibrating electrode, the circular tubular vibrating electrode only generates overall vibration / motion along the longitudinal axis direction of the circular tubular vibrating electrode (also known as longitudinal wave vibration), that is, Figure 5 , Figure 6Its mechanical vibration frequency is consistent with its driving voltage frequency, that is, the vibration frequency is completely controlled by the driving voltage frequency. In this way, the driving voltage frequency can be adjusted according to the change of the static power source, so that the vibration frequency can better adapt to the on-site process changes and enhance the applicability to the on-site environment.

[0074] In addition, if Figure 3 As shown in the figure, a ceramic sleeve is mounted on a cylindrical electrostatic charge induction electrode; the length of the cylindrical electrostatic charge induction electrode is greater than the length of the ceramic sleeve; the cylindrical electrostatic charge induction electrode is partially mounted in the ceramic sleeve along its length direction.

[0075] Specifically, the portion of the cylindrical electrostatic charge induction electrode that exceeds the length of the ceramic sleeve is arranged toward the electrostatic source; the portion of the cylindrical electrostatic charge induction electrode that exceeds the length of the ceramic sleeve is arranged outside the electrostatic voltage sensor housing.

[0076] Furthermore, the central axis of the cylindrical electrostatic charge induction electrode and the ceramic sleeve coincides with the central axis of the tubular vibration electrode; the cylindrical electrostatic charge induction electrode and the ceramic sleeve are arranged in front of the tubular vibration electrode.

[0077] In order to verify the rationality of the above-mentioned vibration electrode structure scheme, a simulation test was carried out on the existing vibration electrode structure and the circular tube detection electrode structure. The method flow of the comparative test is as follows:

[0078] The structural models of the existing electrostatic detection electrode and the tubular electrostatic detection electrode described in the technical solution are respectively constructed; the linear elastic and piezoelectric solid mechanics mathematical models are applied to the overall vibration electrode, and the electrostatic field mathematical model is applied to the piezoelectric ceramic structure (piece); the overall vibration electrode structure is meshed with mapping and scanning operations; simulation operations are performed to obtain corresponding simulation results; the time-varying characteristics of the displacement fields of different vibration electrode structures are analyzed and compared; finally, the superiority of the vibration structure described in the technical solution is determined by the time period for entering the stable state and the ratio of the interfering vibration displacement to the functional (main) vibration displacement.

[0079] Second, the technical solution is described in detail below:

[0080] 1. See Figure 3 , Figure 3-2 , Figure 3-3 , Figure 3-4 , Figure 3-5 As shown in , the technical solution sets up a circular tubular vibration detection electrode A, and the circular tubular vibration detection electrode includes three parts: a metal fixed electrode 1, a circular piezoelectric ceramic piece 3, and a metal vibration electrode 2.

[0081] The fixed electrode 1 is fixedly welded on the circuit board, and the annular piezoelectric ceramic piece 3 is located between the fixed electrode 1 and the vibration electrode 2. The three are bonded or fixed together by conductive adhesive; and the whole is located inside the housing of the static voltage sensor.

[0082] 2. The size of the circular tubular vibrating electrode, especially the size of the inner and outer diameters (h2, h1) and the thickness h3 of the circular piezoelectric ceramic piece, can be set according to the needs of electrostatic detection.

[0083] If the thickness h3 of the annular piezoelectric ceramic plate 3 is increased, the vibration amplitude of the metal vibration electrode 2 can be increased, and then the vibration capacitance between the metal vibration electrode 2 and the cylindrical electrostatic charge induction electrode 4 can be increased, so as to enhance the receiving ability of the electrostatic signal.

[0084] 3. A cylindrical electrostatic charge induction electrode 4 is arranged in front of the cylindrical vibration electrode, and the central axes of the two coincide with each other.

[0085] 4. One end (such as end surface 4 - 1 ) of the cylindrical electrostatic charge sensing electrode 4 faces the electrostatic source.

[0086] The cylindrical electrostatic charge sensing electrode 4 can adjust its relative position with the tubular vibrating electrode on the central axis according to the requirements of electrostatic detection. The cylindrical electrostatic charge sensing electrode 4 can set its diameter and length according to the requirements of detection.

[0087] 5. Furthermore, a cylindrical electrostatic charge sensing electrode 4 can be sleeved in a ceramic sleeve 5.

[0088] The leaked portion of the cylindrical electrostatic charge sensing electrode faces the electrostatic source, and the leaked portion can be located outside the electrostatic voltage sensor housing. The central axis of the two coincides with the central axis of the cylindrical vibrating electrode, and the two are located in front of the cylindrical vibrating electrode. The relative position of the cylindrical vibrating electrode on the central axis can also be adjusted according to detection needs.

[0089] 6. The cylindrical electrostatic charge induction electrode 4 may be close to or in contact with an electrostatic source, and the ceramic sleeve 5 prevents the cylindrical electrostatic charge induction electrode from discharging to the vibration electrode 2 after inducing a large amount of electrostatic charge, thereby damaging / damaging the vibration electrode.

[0090] 7. A sinusoidal voltage is applied to the fixed electrode 1 through the circuit board, and the vibrating electrode 2 can be electrically connected to a zero volt voltage through a lead to drive the annular piezoelectric ceramic piece 3 in the middle, causing it to produce a reciprocating motion in the length direction (axial / detection direction, i.e., the direction of the central axis of the cylindrical electrostatic charge sensing electrode sensing surface (detection surface) 4-1) (i.e., forming a longitudinal wave vibration), ultimately generating a standard sinusoidal oscillation capacitance between the vibrating electrode 2 and the electrostatic charge sensing electrode 4, and forming a standard sinusoidal signal on the electrostatic charge sensing electrode.

[0091] Best embodiment:

[0092] In order to verify the rationality of the above-mentioned vibration electrode structure scheme, simulation tests are carried out on the existing electrostatic detection vibration electrode (hereinafter referred to as the existing vibration electrode) structure and the circular tube electrostatic detection electrode structure of this technical scheme (hereinafter referred to as this circular tube detection electrode). The method flow and result analysis of the comparative test are as follows:

[0093] 1) See Figure 1 , Figure 3 , Figure 3-1 As shown, the structural models of the existing vibration electrode and the circular tube detection electrode are constructed respectively.

[0094] 2) Apply linear elastic and piezoelectric solid mechanics mathematical models to the above two types of vibration electrodes respectively:

[0095] Since the metal vibrating electrode belongs to micro vibration / motion (nano-micrometer level) in actual work, it conforms to the strain equation of linear elastic material in solid mechanics:

[0096]

[0097] S=S inel +S el , ε el =ε-ε inel

[0098] ε inel =ε0+ε th

[0099] S el =C:ε el

[0100] S inel =S0+S ext +S q

[0101]

[0102] C=C(E,ν)

[0103] In the above formula, C is the elastic tensor, a dimensionless number; E is Young's modulus, in Pa, and this technical solution uses the copper Young's modulus of 120e9Pa; ν is Poisson's ratio, a dimensionless number, and this technical solution uses the copper Poisson's ratio of 0.34; u is the material deformation displacement, in m; S is the stress tensor, in N / m 2 ; ρ is the material density, unit: kg / m 3 In this technical solution, the density of copper is 8960kg / m 3 ; F V is the external body force. In this technical solution, there is no additional force. Set FV = 0; ε is the total strain tensor, a dimensionless number; ε th is the thermal strain tensor. This technical solution ignores the thermal effect and assumes ε th =0;ε inel is the inelastic strain tensor; ε el is the elastic strain tensor; ε0 is the initial strain tensor. Since there is no displacement at the initial moment, ε0=0 is set.

[0104] Respectively Figure 2a The welding foot b' and Figure 3-1 The tail end surface 1-1 of the metal fixed electrode 1 is fixed and constrained so that its displacement is zero, that is: u=0.

[0105] because Figure 2a The electrostatic charge sensing electrode e and Figure 3 The electrostatic charge sensing electrodes 4 (including the ceramic sleeve 5) are all soldered to the circuit board, so their displacement constraints are also set to zero, that is, u=0.

[0106] This technical solution uses PZT-5H piezoelectric ceramics, which conform to the following piezoelectric material solid mechanics and electrical equations:

[0107]

[0108] ▽·D=ρ V

[0109] S=S0+S el -E·e

[0110] ε el =ε-ε inel , ε inel =ε0+ε th

[0111]

[0112] S el =c:ε el , c=c(c E ), e=e(e ES )

[0113] D=D r +ε 0,vac ε rs E+e:ε el

[0114]

[0115] In the above formula: c E is the stress charge type elastic matrix, unit is Pa; s Eis the strain charge type compliance matrix, unit 1 / Pa; e ES is the stress-charge coupling matrix, in C / m 2 ;d ET is the strain charge coupling matrix, unit C / N; ε rS is the stress charge type relative dielectric constant of the piezoelectric material, dimensionless; ε rT is the strain charge type relative dielectric constant of the piezoelectric material, dimensionless; ε 0,vac is the vacuum dielectric constant, ε 0,vac =8.854187817×10 -12 F / m; D is the total electric displacement of the piezoelectric material, unit C / m 2 ;D r is the residual electric displacement, in C / m 2 ; E is the electric field intensity, unit V / m; e is the piezoelectric strain tensor, dimensionless number; ρ V is the charge density, in C / m 3 The elastic matrix, coupling matrix and relative dielectric constant of the above materials can be found in the literature.

[0116] 3) Applying the electrostatic field mathematical model to piezoelectric ceramic structures:

[0117] ▽·D=ρ V

[0118] D=ε0E+P(E)+P e (S elast )

[0119] E=-▽V

[0120] P = ε0(ε rS -1)E

[0121] In the above formula: P is the polarization intensity, unit C / m 2 ; ε0 is the dielectric constant of vacuum, ε0=8.854187817×10 -12 F / m, unit F / m; ε rS is the relative dielectric constant of the piezoelectric material, dimensionless; V is the space potential, unit V; P e (S elast ) is the polarization caused by elastic strain, unit C / m 2 .

[0122] 4) A sinusoidal voltage, such as V=5×sin(2×π×f×t), is used to drive the annular piezoelectric ceramic piece 3 and the piezoelectric ceramic piece c in the middle; wherein f is the voltage frequency, and f=450 (Hz).

[0123] For existing vibrating electrodes, a sinusoidal voltage is electrically connected to Figure 2aOn the lead c' in the middle, the vibration plate d is connected to zero volts;

[0124] For the cylindrical detection electrode, the sinusoidal voltage is connected to the Figure 3 The fixed electrode 1 in the circuit is connected to the vibrating electrode 3, while the vibrating electrode 3 can be connected to zero volt through a lead wire.

[0125] 5) Perform meshing including mapping and scanning operations on the overall vibration electrode structure.

[0126] 6) Execute simulation operations to obtain corresponding simulation results; and select Figure 1 , Figure 2a The center point o of the end surface of a vibration plate facing the electrostatic charge induction electrode e is used as the displacement analysis point of the existing vibration electrode, and Figure 3-4 , Figure 3-5 A point o' on the central circumference line of the circular end face of the vibrating electrode 2 facing the electrostatic charge sensing electrode 4 is used as the displacement analysis point of the electrostatic detection electrode of the technical solution, and a time-varying characteristic curve of the displacement field of the two is produced, as shown in FIG. Figure 7 , Figure 8 , Fig. 9 , Fig.10 , Fig.11 , Fig.12 shown.

[0127] 7) Based on the simulation results, analyze and compare the time-varying characteristics of the displacement fields of different vibrating electrode structures, see Fig.13 , Fig.14 .

[0128] from Fig.13 It can be seen that the cylindrical detection electrode achieves stable functional vibration after 5 cycles (about 0.01111s); in this way, the detection / detection signal of the static source will also enter a stable state; this will help the static voltage sensor to enter a stable working state more quickly and achieve stable detection of the static source.

[0129] 8) From Fig.14 It can be seen that the interfering displacement of the vibration detection electrode of the present technical solution is much smaller than that of the existing vibration detection electrode. Therefore, the detected interfering signal is also much smaller than that of the existing vibration detection electrode.

[0130] 9) See Fig.13 As shown, the existing vibration detection electrodes do not effectively form stable vibrations in a very long period (at least 22 periods, about 0.04889 seconds), which will lead to unstable functional detection signals and inability to accurately detect static electricity sources.

[0131] 10) Contrast Figure 2-1 , 2-2 and Figure 5 , Figure 6 , and combined with Fig.13 , Figure 13-1 The circular tubular vibration electrode of the present technical solution has the annular piezoelectric ceramic piece 3 completely covering the end surface of the vibration electrode 2, and due to its own structural reasons, the vibration electrode hardly produces its own local deformation compared with the vibration electrode vibration piece of the prior art, and only produces the overall vibration / movement of the vibration electrode 2, and its main deformation part is concentrated on the annular piezoelectric ceramic piece 3; the mechanical vibration frequency of the vibration electrode 2 is consistent with its driving voltage frequency (while the vibration electrode of the prior art is not consistent), that is, the vibration frequency is completely controlled by the driving voltage frequency; in this way, the driving voltage frequency can be adjusted according to the change of the static power source, so that the vibration frequency can better adapt to the on-site process changes and enhance the applicability to the on-site environment.

[0132] 11) According to Figure 7 , Figure 8 , Fig. 9 , Fig.10 , Fig.11 , Fig.12 The statistical simulation data are used to calculate the ratio of the interfering vibration displacement to the functional (main) vibration displacement of the existing vibration electrode and the circular tube detection electrode:

[0133] For existing vibrating electrodes: take the maximum amplitude in each vibration direction:

[0134]

[0135] For this circular tube detection electrode: take the maximum amplitude in the non-main vibration direction, and take the amplitude during stable vibration in the main vibration direction:

[0136]

[0137] Therefore, it can be seen that the relative interference of the vibration of the circular tube type detection electrode in the non-main vibration direction on the vibration in the main vibration direction is significantly smaller than that of the vibration electrode in the prior art.

[0138] In addition, for existing vibrating electrodes, the displacement in the functional (main) vibration direction mainly occurs in Figure 2-1 , Figure 2-2 In the y-axis direction shown in , relative to the body of the vibration plate of the existing vibration electrode, the front end of the vibration plate performs a "lateral swing" vibration (abbreviated as transverse wave vibration).

[0139] As for the displacement in the functional (main) vibration direction of the circular tube detection electrode, a sinusoidal voltage is applied to the fixed electrode, and the vibrating electrode is connected to a zero volt voltage to drive the annular piezoelectric ceramic piece in the middle to generate a displacement in the length direction (axial direction / detection direction, that is, the central axis direction of the cylindrical electrostatic charge sensing electrode sensing surface (detection surface)). Figure 5, Figure 6 The reciprocating motion along the z-axis (in the center) forms longitudinal vibration, also known as longitudinal wave vibration. The main deformation part is concentrated on the piezoelectric ceramic sheet; the mechanical vibration frequency of the vibrating electrode is consistent with the driving voltage frequency of the piezoelectric ceramic sheet, that is, the vibration frequency is completely controlled by the driving voltage frequency.

[0140] The technical solution of the utility model adopts a vibration electrode with a circular tube structure, and adopts a "circular ring surface" type fixing method for the circular tube vibration electrode. Its functional (main) vibration direction is parallel to the length direction of the vibration electrode, forming a longitudinal wave vibration mode, and the piezoelectric ceramic piece fully covers the extreme vibration end surface; in this way, its startup response speed is faster, saving the time of preheating and debugging of the static voltage sensor, and the time period for entering a stable state is shorter. The driving voltage frequency can be adjusted according to the change of the static power source, so that the vibration frequency can better adapt to the on-site process changes, and the applicability to the on-site environment is enhanced. It can effectively reduce interfering vibrations and the stray capacitance signals caused by them, so that the detection results are more accurate and more stable. It adopts a symmetrical structure with a simple structure, which reduces the difficulty and cost of processing and manufacturing, and can more easily achieve high-precision requirements.

[0141] The utility model can be widely used in the field of designing and manufacturing vibration detection electrodes in static voltage sensors.

Claims

1. A cylindrical vibrating electrode for electrostatic detection, comprising a vibrating electrode for electrostatic detection, characterized in that: The vibrating electrode is a vibrating electrode with a circular tubular structure; The vibrating electrode of the circular tubular structure comprises a circular tubular fixed electrode, a circular annular piezoelectric ceramic piece and a circular tubular vibrating electrode; The cylindrical fixed electrode, the annular piezoelectric ceramic piece and the cylindrical vibrating electrode are coaxially arranged, and the three are sequentially fixedly connected as a whole, and the whole is located inside the housing of the static voltage sensor; The cylindrical fixed electrode is fixed on the circuit board, and the annular piezoelectric ceramic piece is located between the cylindrical fixed electrode and the cylindrical vibrating electrode; The annular piezoelectric ceramic piece completely covers the end surface of the vibration electrode; A cylindrical electrostatic charge induction electrode is arranged in front of the cylindrical vibrating electrode; The central axes of the cylindrical electrostatic charge induction electrode and the cylindrical vibration electrode are arranged to coincide with each other; One end of the cylindrical electrostatic charge induction electrode faces the tubular vibration electrode; The other end of the cylindrical electrostatic charge induction electrode faces the electrostatic source; The cylindrical fixed electrode is electrically connected to the circuit board; The circular tubular vibrating electrode is connected to a zero volt voltage.

2. The cylindrical vibrating electrode for electrostatic detection according to claim 1, characterized in that The circular tubular fixed electrode is a metallic circular tubular fixed electrode; The circular tubular vibration electrode is a metal circular tubular vibration electrode.

3. The cylindrical vibrating electrode for electrostatic detection according to claim 1, characterized in that A ceramic sleeve is mounted on the cylindrical electrostatic charge induction electrode; The length of the cylindrical electrostatic charge induction electrode is greater than the length of the ceramic sleeve; The cylindrical electrostatic charge induction electrode is partially sheathed in the ceramic sleeve along its length direction.

4. The cylindrical vibrating electrode for electrostatic detection according to claim 3, characterized in that The portion of the cylindrical electrostatic charge induction electrode that exceeds the length of the ceramic sleeve is arranged toward the electrostatic source; The portion of the cylindrical electrostatic charge induction electrode that exceeds the length of the ceramic sleeve is arranged outside the housing of the electrostatic voltage sensor.

5. The cylindrical vibrating electrode for electrostatic detection according to claim 3, characterized in that The central axis of the cylindrical electrostatic charge induction electrode and the ceramic sleeve coincides with the central axis of the tubular vibrating electrode; The cylindrical electrostatic charge induction electrode and the ceramic sleeve are arranged in front of the cylindrical vibration electrode.

6. The cylindrical vibrating electrode for electrostatic detection according to claim 1, characterized in that The annular piezoelectric ceramic piece completely covers the end surface of the cylindrical vibrating electrode, so that the cylindrical vibrating electrode only generates overall vibration / movement along the longitudinal axis of the vibrating electrode; the mechanical vibration frequency of the cylindrical vibrating electrode is consistent with the driving voltage frequency of the annular piezoelectric ceramic piece.

7. The cylindrical vibrating electrode for electrostatic detection according to claim 1 or 6, characterized in that The functional vibration direction / main vibration direction of the circular tubular vibration electrode is parallel to or coincides with the length direction of the circular tubular vibration electrode, forming a longitudinal wave vibration mode.

8. The cylindrical vibrating electrode for electrostatic detection according to claim 1, characterized in that The circular tubular fixed electrode is fixed to the circuit board through one end surface of the circular tubular fixed electrode; The cylindrical fixed electrode and the circuit board are fixedly connected as one body by adopting a "surface contact" type fixing structure.

9. The cylindrical vibrating electrode for static electricity detection according to claim 1, characterized in that The other end of the cylindrical electrostatic charge sensing electrode extends out of the housing of the electrostatic voltage sensor and faces the electrostatic power source.

10. The cylindrical vibrating electrode for static electricity detection according to claim 1, characterized in that The sinusoidal voltage is electrically connected to the cylindrical fixed electrode through a circuit board; the cylindrical vibrating electrode is connected to a zero volt voltage; In this way, the annular piezoelectric ceramic piece located between the circular tubular fixed electrode and the circular tubular vibrating electrode is driven, causing the circular tubular vibrating electrode to generate overall vibration / reciprocating motion along the length axis direction of the circular tubular vibrating electrode, forming a longitudinal wave vibration, and ultimately forming a standard sinusoidal oscillation capacitance between the circular tubular vibrating electrode and the cylindrical electrostatic charge induction electrode, and forming a standard sinusoidal signal on the cylindrical electrostatic charge induction electrode.

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