Retractable probe assembly for surface potential measurements

Abstract

The present invention provides a retractable probe device for measuring surface potential, including a shell, a probe core, a contact and a ground terminal. The shell is provided with a guide structure, the probe core is slidably arranged on the guide structure, the shell is connected to the contact and the ground terminal, the probe core is slidably abutted against the contact, and the probe core is movably abutted against the ground terminal. The surface potential is measured by abutting the probe core against the object to be measured, sliding the probe core so that the probe core is retracted to the shell, so that the probe core is away from the surface of the object to be measured, and the probe core is prevented from affecting the surface potential of the object to be measured when the retractable probe device for measuring surface potential is moved. At the same time, when the probe core is retracted to the shell, the probe core abuts against the ground terminal, releasing the residual potential on the probe core. When the object to be measured is tested again by the probe core, the residual potential on the probe core can be prevented from affecting the surface potential of the next position, thereby further preventing the probe core from affecting the surface potential of the object to be measured.

Description

Technical Field

[0001] The invention relates to the technical field of potential measurement, in particular to a retractable probe device for surface potential measurement. Background Art

[0002] The measurement of the surface potential of insulators belongs to the category of electrostatic measurement and cannot be measured with traditional electrical instruments. At present, the measurement methods of surface potential mainly include dust map method, optical measurement method based on Pockels effect and electrostatic probe method. The dust map method was first proposed by Lichtenberg in 1778. Its principle is to use certain charged colored solids, such as positively charged red Pb3O4 and negatively charged white-yellow S, to have an adsorption effect with the charge on the surface of the insulator. For example, negative charge will adsorb positively charged Pb3O4, and positive charge will adsorb negatively charged S. When these special solid powders are sprayed on the surface of the medium, the potential polarity and potential distribution of the medium surface can be judged according to the color distribution of these solid powders on the surface of the medium. Its advantages are convenience and intuitiveness, and its disadvantages are that it cannot quantitatively characterize the surface potential, and the potential distribution on the surface of the medium may be changed during the dust spraying process. The Pockels effect optical measurement method is the linear electro-optical effect method. For a crystal that does not have a symmetry center, when it is in an electric field, the change in its refractive index is proportional to the applied electric field strength, that is, it is already quite obvious when the electric field is not too strong. Therefore, the change in the electric field can be reflected by measuring the change in the refractive index of the crystal under the action of the electric field. However, this method is only applicable to transparent films and is not suitable for the solid surface of pot-type insulators.

[0003] At present, the electrostatic probe method is the most widely used method in the field of surface potential measurement in the world. The electrostatic probe is mainly composed of an internal induction conductor, an internal supporting insulator and an external grounding shielding layer. When measuring the surface potential of the insulator, the probe is perpendicular to the surface of the medium to be measured and the distance is constant. The surface potential of the insulator will excite an induced voltage on the induction conductor, and the output induced voltage can be measured. When only the distribution law and influencing factors of the surface potential are examined and the experimental results under different conditions are compared horizontally, the traditional linear scaling method is used to calculate the surface potential of the insulator.

[0004] For insulating solid surfaces, the commonly used measurement method is the electrostatic capacitance probe method. However, due to the limitation of measurement distance, when the conventional retractable probe device used for surface potential measurement is close to the insulating solid surface during movement, it will have a greater impact on the surface potential and affect the accuracy of the measurement data. Summary of the invention

[0005] Based on this, it is necessary to provide a retractable probe device for surface potential measurement.

[0006] A retractable probe device for measuring surface potential comprises a shell, a probe core, a contact and a ground terminal, wherein the shell is provided with a guide structure, the probe core is slidably arranged on the guide structure, the shell is connected to the contact and the ground terminal, the probe core is slidably abutted against the contact, and the probe core is movably abutted against the ground terminal.

[0007] The retractable probe device for measuring surface potential in the above-mentioned embodiment measures the surface potential on the object to be measured by abutting the probe core against the object to be measured. When measuring multiple points horizontally on the surface of the object to be measured, the probe core is slid after measuring the surface potential at the current position, so that the probe core is retracted onto the shell, so that the probe core is away from the surface of the object to be measured, thereby avoiding the probe core affecting the surface potential of the object to be measured when the retractable probe device for measuring surface potential is moved. At the same time, when the probe core is retracted onto the shell, the probe core abuts against the ground terminal to release the residual potential on the probe core. When the object to be measured is tested by the probe core again, the residual potential on the probe core can be avoided from affecting the surface potential at the next position, thereby further avoiding the probe core from affecting the surface potential of the object to be measured, thereby improving the accuracy of measuring the surface potential by the retractable probe device for measuring surface potential.

[0008] In one embodiment, the contact is provided with a limit channel, the probe core is inserted into the limit channel, and is slidably abutted against a side wall of the limit channel.

[0009] In one of the embodiments, it further includes an insulating support member, wherein the insulating support member is disposed on the shell, and the guide structure is disposed on the insulating support member.

[0010] In one embodiment, the guide structure is a sliding channel opened in the insulating support member, the probe core is inserted into the sliding channel, and is in sliding contact with the side wall of the sliding channel.

[0011] In one of the embodiments, a bump is protruded from the outer surface of the insulating support.

[0012] In one embodiment, an elastic member is further included, one end of the elastic member is connected to the shell, and the other end of the elastic member is connected to the core probe.

[0013] In one embodiment, the elastic member is a spring.

[0014] In one embodiment, it further includes a first electromagnet and a magnetic component, wherein one of the first electromagnet and the magnetic component is disposed on the shell, and the other is disposed on the probe core, and the first electromagnet and the magnetic component are attracted to each other to make the probe core slide along the guide structure.

[0015] In one of the embodiments, a shielding cover is further included, wherein the shielding cover is connected to the shell, the shielding cover is provided with a shielding channel, and the probe core is at least partially disposed in the shielding channel.

[0016] In one of the embodiments, a signal output module is further included, and the contact is electrically connected to the signal output module. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 A schematic cross-sectional structure diagram of a retractable probe device for measuring surface potential in one state according to an embodiment;

[0018] Figure 2 The figure is a schematic cross-sectional structure diagram of a retractable probe device for measuring surface potential in another state according to an embodiment. DETAILED DESCRIPTION

[0019] In order to facilitate the understanding of the present invention, the present invention will be described more fully below with reference to the relevant drawings. The preferred embodiments of the present invention are given in the drawings. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the disclosure of the present invention more thoroughly understood.

[0020] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used herein in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more related listed items.

[0021] In one embodiment, if Figure 1 and Figure 2As shown, a retractable probe device 10 for measuring surface potential includes a housing 100, a probe core 200, a contact 300 and a ground terminal 400. The housing 100 is provided with a guide structure, the probe core 200 is slidably provided on the guide structure, the housing 100 is connected with the contact 300 and the ground terminal 400, the probe core 200 is in sliding contact with the contact 300, and the probe core 200 is movably in contact with the ground terminal 400. In this embodiment, the probe core 200 is in continuous sliding contact with the contact 300 during the process of extension and retraction, that is, during the process of the probe core 200 sliding along the guide structure, the probe core 200 is always in sliding contact with the contact 300, and the contact 300 is used to be electrically connected to the signal output module 310, and is used to keep the probe core 200 and the signal output module 310 in an electrically connected state at all times, so that the surface potential measured by the probe core 200 can be continuously transmitted to the signal output module 310. In this embodiment, the probe core 200 slides along the guide structure, and the probe core 200 at least partially protrudes from the housing 100 as it slides, so that the protruding portion of the probe core 200 contacts the object to be detected, making detection more convenient.

[0022] In this embodiment, an installation cavity is opened inside the shell, the guide structure is arranged in the installation cavity, the installation cavity has a through hole, the probe core is movably arranged in the installation cavity, and the probe core is movably inserted in the through hole, the probe core at least partially protrudes from the through hole, the contact is arranged in the installation cavity, and the grounding terminal is arranged on the side wall of the installation cavity away from the through hole. In this way, when the probe core slides along the guide structure in the installation cavity, the probe core will slide toward the outside of the through hole, so that one end of the probe core extends out of the through hole, and when the probe core moves in the opposite direction, the other end of the probe core abuts against the grounding terminal.

[0023] See also Figure 1 The retractable probe device 10 for measuring surface potential in the above-mentioned embodiment measures the surface potential of the object to be measured by placing the probe core 200 against the object to be measured. When measuring multiple points on the surface of the object to be measured in the horizontal direction, the probe core 200 is slid after measuring the surface potential at the current position, so that the probe core 200 is retracted onto the housing 100, so that the probe core 200 is away from the surface of the object to be measured, so as to avoid the probe core 200 affecting the surface potential of the object to be measured when the retractable probe device 10 for measuring surface potential is moved. At the same time, please refer to Figure 2When the probe core 200 is retracted into the shell 100, the probe core 200 abuts against the ground terminal 400, releasing the residual potential on the probe core 200. When the probe core 200 is used to test the object to be tested again, the residual potential on the probe core 200 can be prevented from affecting the surface potential of the next position, thereby further preventing the probe core 200 from affecting the surface potential of the object to be tested, thereby improving the accuracy of measuring the surface potential of the retractable probe device 10 for surface potential measurement.

[0024] like Figure 1 and Figure 2 As shown, in one embodiment, the shell 100 is provided with an installation cavity 101, and the installation cavity 101 has a through hole 102, and the probe core 200 is movably passed through the through hole 102, the guide structure is arranged on the side wall of the installation cavity 101, the grounding terminal 400 is arranged on the side wall of the installation cavity 101, part of the probe core 200 is arranged in the installation cavity 101, and at least part of the probe core 200 is movably arranged outside the installation cavity 101, that is, at least part of the probe core 200 movably protrudes from the outside of the shell 100.

[0025] In one embodiment, the material of the probe core is copper, which has good electrical conductivity. In one embodiment, the shape of the probe core is cylindrical, so that the charges on the probe core are evenly conducted and distributed, making the test results more accurate. In one embodiment, the cross-sectional diameter of the probe core is 1 mm and the total length is 60 mm.

[0026] In one embodiment, the grounding terminal is made of brass, placed on one side of the probe core, and corresponding to one end of the probe core. The grounding terminal is also connected to a grounding wire, which is used for grounding. When the probe core is retracted into the shell, the probe core contacts the grounding terminal to release the residual potential. Brass has better hardness than copper while taking into account conductivity. Because the probe core needs to touch the grounding terminal many times during the measurement process, the grounding terminal made of brass has good hardness, which reduces the damage of the contact terminal during the abutment process and can extend the service life of the grounding terminal.

[0027] In order to make the contact 300 more stably slide against the probe core 200, as shown in FIG. Figure 1 and Figure 2 As shown, in one embodiment, the contact 300 is provided with a limiting channel 301, and the probe core 200 is inserted into the limiting channel 301 and slidably abuts against the side wall of the limiting channel 301. By inserting the probe core 200 into the limiting channel 301, the probe core 200 will slide along the limiting channel 301 during the sliding process, thereby avoiding the deviation of the probe core 200, so that the probe core 200 can more stably slide against the contact 300, and at the same time play the role of limiting the reciprocating motion of the probe core 200.

[0028] In order to make the surface potential measurement data more accurate, Figure 1 and Figure 2 As shown, in one embodiment, the retractable probe device 10 for measuring surface potential further includes an insulating support 800, which is disposed on the housing 100, and is placed between the housing 100 and the probe core 200, and supports and insulates the probe core 200, and the guide structure is disposed on the insulating support 800. The insulating support 800 provides insulation for the housing and the probe core, and can reduce charge leakage, thereby making the measurement data more accurate.

[0029] To further avoid charge leakage, Figure 1 and Figure 2 As shown, in one embodiment, the guide structure is a sliding channel 801 provided in the insulating support 800, and the probe core 200 is disposed in the sliding channel 801 and slides against the side wall of the sliding channel 801. On the one hand, the sliding channel 801 guides the probe core 200, so that the probe core 200 slides along the sliding channel 801. On the other hand, the sliding channel 801 is provided on the insulating support 800, so that the probe core 200 is accommodated in the insulating support 800, so that the insulating support 800 further reduces charge leakage, thereby making the measurement data more accurate.

[0030] To further reduce charge leakage, Figure 1 and Figure 2 As shown, in one embodiment, the outer surface of the insulating support member 800 is provided with a protrusion 810. The protrusion 810 increases the creepage distance of the outer surface of the insulating support member 800, thereby further reducing charge leakage, so that the measurement data is more accurate. In one embodiment, the number of the protrusions 810 is multiple, thereby further increasing the creepage distance and reducing charge leakage. In one embodiment, each of the protrusions 810 is provided in a protruding manner along the radial direction of the insulating support member 800. In one embodiment, each of the protrusions 810 is provided at intervals along the axial direction of the insulating support member 800, that is, the insulating support member 800 has an umbrella skirt structure, thereby increasing the creepage distance and reducing charge leakage.

[0031] In one embodiment, the insulating support member 800 is made of rubber. In one embodiment, the insulating support member 800 is made of plastic.

[0032] To facilitate the resetting of the probe core 200, Figure 1 and Figure 2As shown, in one embodiment, the retractable probe device 10 for measuring surface potential further includes an elastic member 500, one end of which is connected to the housing 100, and the other end of which is connected to the probe core 200. In this embodiment, when the probe core 200 is retracted into the housing 100, the elastic potential energy of the elastic member 500 increases, and when no force is applied to the probe core 200, the elastic potential energy of the elastic member 500 decreases, and the probe core 200 is pushed to protrude out of the housing 100, so that the probe core 200 is reset.

[0033] In one embodiment, the elastic member is a spring. When the probe moves toward the ground terminal, the spring is compressed and gains elastic potential energy. Subsequently, when the probe is not subjected to other external forces, the spring does work on the probe and pushes the probe out of the through hole through elasticity, so that the probe extends. In one embodiment, the elastic member is a spring.

[0034] To drive the probe core 200 to slide on the guide structure, as Figure 1 and Figure 2 As shown, in one embodiment, the retractable probe device 10 for measuring surface potential further includes a first electromagnet 610 and a magnetic member 620, one of which is disposed on the housing 100, and the other is disposed on the probe core 200, and the first electromagnet 610 and the magnetic member 620 are mutually attracted to make the probe core 200 slide along the guide structure. In this embodiment, when the first electromagnet 610 is powered on, it attracts the magnetic member 620, so that the probe core 200 slides on the guide structure.

[0035] In one embodiment, if Figure 1 and Figure 2As shown, the first electromagnet 610 is arranged on the housing 100, and the magnetic member 620 is arranged on the probe core 200. When the first electromagnet 610 is powered on, it attracts the magnetic member 620 and drives the probe core 200 to slide along the guide structure, so that the probe core 200 is stored inside the housing 100. At the same time, the elastic member 500 obtains elastic potential energy, and the probe core 200 abuts against the ground terminal 400, releasing the charge on the probe core 200. Then, the first electromagnet 610 is powered off, the elastic potential energy of the elastic member 500 decreases, and the probe core 200 is driven to slide along the guide structure, so that the probe core 200 protrudes from the outside of the housing 100, and the connection between the probe core 200 and the ground terminal 400 is disconnected, so as to measure the surface potential of the object to be measured for the next time. In this embodiment, the first electromagnet 610 is disposed on the side wall of the installation cavity 101, and a power-through hole (not shown) is provided on the side wall of the installation cavity 101, and the power-through hole is used to pass a wire (not shown), one end of the wire is electrically connected to the first electromagnet 610, and the other end of the wire is used to connect to the electromagnetic group controller 900, so as to energize the first electromagnet 610 through the electromagnetic group controller 900. In this embodiment, the first electromagnet 610 and the magnetic member 620 are both small in size and can be installed in a compact space, so as to avoid increasing the volume of the retractable probe device 10 for surface potential measurement, and keep the retractable probe device 10 for surface potential measurement light.

[0036] like Figure 1 and Figure 2 As shown, in one embodiment, an insulator 820 is provided between the magnetic member 620 and the probe core 200, and the insulator 820 is used to isolate the charge conduction between the probe core 200 and the magnetic member 620, and prevent the charge from being conducted between the probe core 200 and the magnetic member 620, so that the potential on the probe core 200 is consistent with the surface potential on the object to be measured, so that the measurement result is more accurate. In this embodiment, the first end of the elastic member 500 is connected to the first electromagnet 610, and the second end of the elastic member 500 is connected to the magnetic member 620, that is, the elastic member 500 is connected to the housing 100 through the first electromagnet 610, and the elastic member 500 is connected to the probe core 200 through the magnetic member 620 and the insulator 820.

[0037] In another embodiment, the magnetic member is disposed on the housing, and the first electromagnet is disposed on the probe core. In this embodiment, an insulator is disposed between the probe core and the first electromagnet so that the potential on the probe core matches the surface potential of the object to be measured, so that the measurement result is accurate.

[0038] To realize the magnetic function of the magnetic member, in one embodiment, the magnetic member is iron. In one embodiment, the magnetic member is cobalt. In one embodiment, the magnetic member is nickel. Iron, cobalt and nickel have magnetism, and the magnetic member is made of iron, cobalt or nickel, so that the first electromagnet in the power-on state can attract the magnetic member.

[0039] In order to realize the magnetic function of the magnetic part, in one embodiment, the magnetic part is an iron alloy. In one embodiment, the magnetic part is a cobalt alloy. In one embodiment, the magnetic part is a nickel alloy. Iron, cobalt and nickel have magnetism, and the magnetic part is made of alloys of these metals, so that the first electromagnet in the energized state can attract the magnetic part.

[0040] In one embodiment, the magnetic member is a lanthanide alloy. The lanthanide alloy has magnetism, and the magnetic member is made of the lanthanide alloy, so that the first electromagnet in the energized state can attract the magnetic member.

[0041] In order to make the first electromagnet attract the magnetic part, in one embodiment, the first electromagnet includes a first iron core and a first coil, and the first coil is spirally arranged along the outer surface of the first iron core, that is, the first coil is sleeved on the first iron core, and after the first coil is energized, the first iron core is magnetized by the magnetic field of the first coil, and the magnetized first iron core has magnetism, thereby attracting the magnetic part. In this embodiment, the wire is electrically connected to the first coil.

[0042] In one embodiment, the retractable probe device for measuring surface potential includes a second electromagnet and a third electromagnet, wherein the second electromagnet is arranged on the shell, and the third electromagnet is arranged on the probe core, and the second electromagnet and the third electromagnet are mutually attracted to make the probe core slide along the guide structure. In this embodiment, the second electromagnet and the third electromagnet are energized respectively, so that the second electromagnet and the third electromagnet are mutually attracted, so that the probe core slides along the guide structure, so that the probe core is stored inside the shell, and at the same time, the elastic member obtains elastic potential energy, and the probe core abuts against the ground terminal to release the charge on the probe core. Then, the second electromagnet and the third electromagnet are de-energized, the elastic potential energy of the elastic member decreases, and the probe core is driven to slide along the guide structure, and the probe core protrudes from the outside of the shell, and at the same time, the connection between the probe core and the ground terminal is disconnected, so as to measure the surface potential of the object to be measured for the next time.

[0043] To realize the magnetic function of the second electromagnet and the third electromagnet, in one embodiment, the second electromagnet includes a second core and a second coil, the second coil is spirally arranged along the outer surface of the second core, after the second coil is energized, the second core is magnetized by the magnetic field of the second coil, and the magnetized second core has magnetism, the third electromagnet includes a third core and a third coil, the third coil is spirally arranged along the outer surface of the third core, after the third coil is energized, the third core is magnetized by the magnetic field of the third coil, and the magnetized third core has magnetism, in this embodiment, the current direction of the second coil is the same as that of the third coil and the winding direction is opposite, when the second electromagnet and the third electromagnet are respectively in the energized state, the second electromagnet and the third electromagnet are mutually attracted. In another embodiment, the current direction of the second coil and the third coil is opposite and the winding direction is the same, when the second electromagnet and the third electromagnet are respectively in the energized state, the second electromagnet and the third electromagnet are mutually attracted.

[0044] In order to make the measurement result of the retractable probe device 10 for measuring surface potential more accurate, Figure 1 and Figure 2 As shown, in one embodiment, the retractable probe device 10 for measuring surface potential further includes a shielding cover 700, the shielding cover 700 is connected to the shell 100, the shielding cover 700 is provided with a shielding channel, the probe core 200 is at least partially penetrated in the shielding channel, and the shielding channel is connected to the installation cavity. The shielding cover 700 can play the role of electrostatic shielding for the probe core 200, eliminate spatial electromagnetic interference, thereby avoiding interference with the measurement result, making the measurement more accurate. In this embodiment, the shielding cover 700 is arranged around the outer surface of the probe core 200 protruding from one end of the shell 100, that is, the shielding cover 700 is arranged around the end of the probe core 200 that contacts the object to be measured. It plays the role of electrostatic shielding for the probe core 200, eliminates spatial electromagnetic interference, and makes the measurement result more accurate.

[0045] To achieve a better shielding effect, in one embodiment, the shielding cover is made of aluminum. In one embodiment, the shielding cover is made of aluminum alloy, and aluminum and aluminum alloy have excellent shielding performance.

[0046] To output the surface potential data measured by the probe core 200, such as Figure 1 and Figure 2As shown, in one embodiment, the retractable probe device 10 for surface potential measurement further includes a signal output module 310, and the contact 300 is electrically connected to the signal output module 310. In this embodiment, an output hole is provided on the housing 100, and the output hole is communicated with the mounting cavity 101. The signal output module 310 is inserted into the output hole, and the contact 300 is arranged in the mounting cavity 101. One end of the signal output module 310 is connected to the contact 300 located in the mounting cavity 101, and the other end of the signal output module 310 is arranged outside the mounting cavity 101. The end of the signal output module 310 away from the contact 300 is used to be electrically connected to the potential tester body, so as to reflect the surface potential data on the potential tester body.

[0047] In one of the embodiments, the signal output module includes an SMA interface (Sub-Miniature-A), and the SMA interface is used to connect to the potential tester body.

[0048] In order to further prevent the charge on the probe core from affecting the surface potential of the object to be measured, in one embodiment, the retractable probe device for measuring surface potential further includes a paddle, one end of which is flexibly connected to the housing, the other end of which is a free end, and the paddle movable cover is disposed on the through hole. In this embodiment, there are multiple paddles, each of which is disposed around the through hole, and each of which has a movable cover disposed on the through hole. Specifically, the paddle is insulating, that is, the paddle is an insulating paddle, and the paddle is flexible, that is, the paddle is an insulating flexible paddle, and each of the paddles movably closes the through hole. In this embodiment, when the probe core protrudes from the shell, the free end of the paddle abuts against the outer surface of the probe core, so the probe core can smoothly measure the object to be measured. When the probe core is retracted into the installation cavity, the paddle movably covers the through hole and closes the through hole. Since the paddle has insulating properties, it can prevent the charge of the probe core from leaking to the surface of the object to be measured, thereby avoiding affecting the surface potential of the object to be measured and making the measurement more accurate. Specifically, the cross-section of each of the paddles is triangular, two corners of each of the paddles are connected to the shell, and the other corner is a free end. When each of the paddle covers is arranged on the through hole, each of the paddles is spliced ​​to form a polygon, and the cover is arranged on the through hole. This structure can ensure that the probe core passes through the paddle smoothly, that is, the probe core can smoothly push the free end of each of the paddles, thereby protruding out of the shell setting. When the probe core is retracted into the installation cavity, the free ends of each of the paddles are close to each other, so that each of the paddles is spliced ​​to form a polygon, and the cover is arranged on the through hole to prevent charge leakage.

[0049] In one embodiment, the material of the plectrum is rubber. In one embodiment, the material of the plectrum is silicone rubber.

[0050] It is worth mentioning that the retractable probe device for measuring surface potential can be simply referred to as a retractable probe device, or simply referred to as a probe device.

[0051] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0052] The above-mentioned embodiments only express several implementation methods of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A retractable probe device for measuring surface potential, characterized in that: The invention comprises a shell, a probe core, a contact, a grounding terminal, an insulating support, a first electromagnet and a magnetic part. The shell is provided with a guide structure. The probe core is slidably arranged on the guide structure. The shell is connected to the contact and the grounding terminal. The probe core slides and abuts against the contact. The insulating support is arranged between the shell and the probe core. The guide structure is a sliding channel opened in the insulating support. The probe core is inserted into the sliding channel and slides and abuts against the side wall of the sliding channel. The surface potential on the object to be measured is measured by abutting the probe core against the object to be measured. After measuring the surface potential, the probe core is slid so that the probe core is retracted into the shell. When the probe core is retracted into the shell, the probe core abuts against the grounding terminal. One of the first electromagnet and the magnetic part is arranged on the shell, and the other is arranged on the probe core. The first electromagnet and the magnetic part attract each other to make the probe core slide along the guide structure. An insulator is arranged between the magnetic part and the probe core.

2. The retractable probe device for surface potential measurement according to claim 1, characterized in that: The contact is provided with a limit passage, the probe core is arranged in the limit passage, and is slidably abutted against the side wall of the limit passage.

3. The retractable probe device for surface potential measurement according to claim 1, characterized in that: The outer surface of the insulating support is protruded with a bump.

4. The retractable probe device for surface potential measurement according to claim 1, characterized in that: It also includes an elastic member, one end of which is connected to the shell, and the other end of which is connected to the core probe.

5. The retractable probe device for surface potential measurement according to claim 4, characterized in that: The elastic member is a spring.

6. The retractable probe device for measuring surface potential according to any one of claims 1 to 5, characterized in that: It also includes a shielding cover, which is connected to the shell, and has a shielding channel, and the probe core is at least partially inserted into the shielding channel.

7. The retractable probe device for measuring surface potential according to any one of claims 1 to 5, characterized in that: It also includes a signal output module, and the contact is electrically connected to the signal output module.

8. The retractable probe device for surface potential measurement according to claim 1, characterized in that: The material of the probe core is copper.

9. The retractable probe device for surface potential measurement according to claim 1, characterized in that: The shape of the probe core is cylindrical.

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