Point type capacitive sensor

Abstract

The utility model discloses a point-type capacitive sensor, and belongs to the technical field of injection molding. The utility model provides a point-type capacitive sensor, which comprises a shell, a first insulating sheet, a pole piece, a pin, a second insulating sheet, a gasket, a pressing block, a rear cover and a fixing assembly, the first insulating sheet and the shell are sequentially arranged outside the pole piece in a sleeving manner, the contact pin is fixed in the pole piece, a wiring hole is formed in the contact pin, and the cable sequentially penetrates through the second insulating sheet, the gasket, the pressing block, the rear cover and the fixing assembly and then is connected with the capacitance measuring circuit; the pressing piece is fixedly connected with the shell, the rear cover is fixedly connected with the pressing block and the fixing assembly, and the fixing assembly is fixedly connected with the mold. Compared with a conventional pressure sensor and the like, the point-type capacitance sensor can only detect single or partial parameters, the state change of melt in a mold cavity can be detected by collecting capacitance signals of the point-type capacitance sensor, and real-time monitoring and sensing of all stages in the injection molding process are achieved; compared with a plate capacitor, the structure is simple and small, installation is convenient, and the application range is wider.

Description

Technical Field

[0001] The utility model relates to the technical field of injection molding, in particular to a point-type capacitance sensor. Background Art

[0002] Existing injection mold sensors are mainly used to detect the pressure or temperature in the mold cavity of the mold, including resistance strain sensors, piezoelectric sensors, piezoresistive pressure sensors, inductive pressure sensors, etc. These sensors can only detect single parameters, cannot monitor the entire injection molding process, have low detection accuracy, and are greatly affected by the medium state in the mold cavity, making it difficult to achieve real-time monitoring and perception.

[0003] Therefore, on the market, there appears a flat capacitance sensor used to detect the state of the melt in the injection mold. By real-time monitoring the signal of the flat capacitance sensor, the state of the melt during the entire injection process can be perceived. However, the flat capacitor is only applicable to molds with a planar structure, and its applicability is relatively narrow. Summary of the Utility Model

[0004] Aiming at the above problems of the prior art, the utility model provides a point-type capacitance sensor with a small and compact structure and a wider application range.

[0005] The point-type capacitance sensor provided by the utility model includes a housing, a probe assembly, a guiding assembly, an insulating assembly, and a fixing assembly; wherein:

[0006] The probe assembly includes a pole piece and a pin.

[0007] The guiding assembly includes a gasket, a pressing block, and a rear cover, and the guiding assembly is used to guide and fix the probe assembly.

[0008] The insulating assembly includes a first insulating sheet and a second insulating sheet, and the insulating assembly is used to insulate and protect the probe assembly.

[0009] Both the first insulating sheet and the housing are hollow rotaries with a ring-shaped flange at one end; the pole piece is a rotary body with a closed flange at one end; the first insulating sheet and the housing are sleeved and fixed on the outside of the pole piece in sequence.

[0010] Both the second insulating sheet, the gasket, the pressing block, the rear cover, and the fixing assembly are of hollow structures.

[0011] On one side of the pole piece close to the rotary body in the axial direction, there is a pin accommodating hole; the length of the pin accommodating hole is equal to the length of the pin; the pin is fixed in the pin accommodating hole; a wiring hole is arranged in the pin; a cable is connected to the wiring hole, passes through the second insulating sheet, the gasket, the pressing block, the rear cover, and the fixing assembly in sequence and is connected to a capacitance measurement circuit.

[0012] The briquette is fixedly connected to the outer shell;

[0013] Both ends of the rear cover are respectively inserted into the hollow spaces of the briquette and the fixing component, and are fixedly connected to the briquette and the fixing component; the fixing component is fixedly connected to the mold.

[0014] Preferably, a first notch is provided along the axial direction at one end of the pin near the fixing component.

[0015] Preferably, the pin receiving hole of the pole piece is provided with an internal thread, the outer surface of the pin is provided with an external thread, and the pin is threadedly connected to the pole piece.

[0016] Preferably, a first groove and a second groove are respectively provided at one ends of the pole piece and the gasket facing the second insulating sheet, and the inner diameters of the first groove and the second groove are both equal to the outer diameter of the second insulating sheet.

[0017] Preferably, the outer surface of the briquette is provided with an external thread, one end of the outer shell near the briquette is provided with an internal thread, and the briquette is threadedly connected to the outer shell.

[0018] Preferably, one end of the briquette near the rear cover is provided with an internal thread, one end of the rear cover near the briquette is provided with an external thread, and the rear cover is threadedly connected to the briquette.

[0019] Preferably, the fixing component is a hollow nut, and concavo-convex structures are provided at one end of the rear cover near the hollow nut and at one end of the hollow nut near the rear cover, and the rear cover is connected to the hollow nut in a concavo-convex fit manner.

[0020] Preferably, the hollow nut has a second notch penetrating through its entire axial length.

[0021] Preferably, the outer diameter of the flange portion of the pole piece is equal to the inner diameter of the flange portion of the first insulating sheet; the outer diameter of the flange portion of the first insulating sheet is equal to the inner diameter of the flange portion of the outer shell; the length of the first insulating sheet is equal to the length of the flange portion of the pole piece.

[0022] Preferably, the outer surface of the pole piece and the inner surface of the first insulating sheet are fixed by a high-temperature resistant adhesive, and the outer surface of the first insulating sheet and the inner surface of the outer shell are fixed by a high-temperature resistant adhesive.

[0023] The utility model has the following beneficial effects: The dot-type capacitive sensor provided by the utility model includes a housing, a first insulating sheet, a pole piece, a pin, a second insulating sheet, a gasket, a pressing block, a rear cover, and a fixing component; the first insulating sheet and the housing are sleeved outside the pole piece in sequence, the pin is fixed inside the pole piece, a wiring hole is arranged inside the pin, and a cable is connected to a capacitance measurement circuit after passing through the second insulating sheet, the gasket, the pressing block, the rear cover, and the fixing component in sequence; the pressing sheet is fixedly connected to the housing, the rear cover is fixedly connected to the pressing block and the fixing component, and the fixing component is fixedly connected to a mold. The dot-type capacitive sensor provided by the utility model, compared with conventional sensors such as pressure sensors that can only detect single or partial parameters, can detect the change of the melt state in the mold cavity by collecting the capacitance signal of the dot-type capacitive sensor, realizing real-time monitoring and perception of each stage of the injection molding process; compared with a flat capacitor, it has a simple and compact structure, is convenient to install, and has a wider application range. Description of the Drawings

[0024] Figure 1 It is an exploded view of the structure of the dot-type capacitive sensor provided by an embodiment of the utility model.

[0025] Figure 2 It is a three-dimensional view of the assembled dot-type capacitive sensor provided by an embodiment of the utility model.

[0026] Figure 3 It is an axial sectional view of the dot-type capacitive sensor provided by an embodiment of the utility model.

[0027] Figure 4 It is an axial sectional view of the housing of the dot-type capacitive sensor provided by an embodiment of the utility model.

[0028] Figure 5 It is an axial sectional view of the first insulating sheet of the dot-type capacitive sensor provided by an embodiment of the utility model.

[0029] Figure 6 It is a side view of the pole piece of the dot-type capacitive sensor provided by an embodiment of the utility model.

[0030] Figure 7 It is Figure 6 a sectional view along the A-A direction.

[0031] Figure 8 It is a side view of the pin of the dot-type capacitive sensor provided by an embodiment of the utility model.

[0032] Figure 9 It is a side view of the second insulating sheet of the dot-type capacitive sensor provided by an embodiment of the utility model.

[0033] Figure 10 It is a three-dimensional view of the gasket of the dot-type capacitive sensor provided by an embodiment of the utility model.

[0034] Figure 11 The sectional view of the gasket of the point - type capacitive sensor provided by the embodiment of the present utility model.

[0035] Figure 12 The three - dimensional view of the pressing piece of the point - type capacitive sensor provided by the embodiment of the present utility model.

[0036] Figure 13 The side view of the pressing piece of the point - type capacitive sensor provided by the embodiment of the present utility model.

[0037] Figure 14 is Figure 13 The sectional view along the B - B direction.

[0038] Figure 15 The three - dimensional view of the rear cover of the point - type capacitive sensor provided by the embodiment of the present utility model.

[0039] Figure 16 The side view of the rear cover of the point - type capacitive sensor provided by the embodiment of the present utility model.

[0040] Figure 17 is Figure 16 The sectional view along the A - A direction.

[0041] In the attached drawings:

[0042] 100, housing;

[0043] 200, probe assembly; 210, pole piece; 211, pin accommodation hole; 212, first groove; 220, pin; 221, wiring hole; 222, first notch;

[0044] 300, guiding assembly; 310, gasket; 311, second groove; 320, pressing block; 321, gasket connection part; 322, housing connection part; 3221, thread part; 3222, control part; 323, rear - cover connection part; 330, rear cover;

[0045] 400, insulating assembly; 410, first insulating sheet; 420, second insulating sheet;

[0046] 500, fixing assembly; 510, second notch. Detailed implementation manners

[0047] In order to have a clearer understanding of the technical features, purposes and effects of the present utility model, the detailed implementation manners of the present utility model will now be described in detail with reference to the attached drawings.

[0048] The dot-type capacitance sensor provided by the utility model is suitable for being installed in an injection mold or an injection molding machine. By monitoring the change of the melt state in the cavity of the injection mold, it can realize the real-time perception of each stage of the injection molding process, and provide a basis for the monitoring and control of the injection molding process and the quality inspection and control of products.

[0049] As Figures 1 - 17 shown, an embodiment of the utility model provides a dot-type capacitance sensor, which includes a housing 100, a probe assembly 200, a guiding assembly 300, an insulating assembly 400, and a fixing assembly 500; wherein:

[0050] The probe assembly 200 includes a pole piece 210 and a pin 220;

[0051] The guiding assembly 300 includes a gasket 310, a pressing block 320, and a rear cover 330. The guiding assembly 300 is used for guiding and fixing the probe assembly 200;

[0052] The insulating assembly 400 includes a first insulating sheet 410 and a second insulating sheet 420. The insulating assembly 400 is used for insulating and protecting the probe assembly 200. The first insulating sheet 410 is used for insulating the probe assembly from the housing 100, and the second insulating sheet 420 is used for insulating the probe assembly from the guiding assembly. By arranging the insulating assembly 400, the effectiveness and stability of the capacitance signal can be improved.

[0053] Both the first insulating sheet 410 and the housing 100 are hollow rotating bodies with a ring-shaped flange at one end; the pole piece 210 is a rotating body with a closed flange at one end; the first insulating sheet 410 and the housing 100 are sleeved and fixed on the outside of the pole piece 210 in sequence. The housing 100 is used for protecting the probe assembly 200.

[0054] Both the second insulating sheet 420, the gasket 310, the pressing block 320, the rear cover 330, and the fixing assembly 500 are hollow structures;

[0055] On one side of the pole piece 210 close to the rotating body in the axial direction, a pin receiving hole 211 is provided; the length of the pin receiving hole 211 is equal to the length of the pin 220; the pin 220 is fixed in the pin receiving hole 211; a wiring hole 221 is provided in the pin 220; the cable is connected to the wiring hole 221, sequentially passes through the second insulating sheet 420, the gasket 310, the pressing block 320, the rear cover 330, the fixing assembly 500, and is connected to the capacitance measurement circuit. The holes in the second insulating sheet 420, the gasket 310, the pressing block 320, the rear cover 330, and the fixing assembly 500 are coaxial holes. After the cable passes through the coaxial holes of the second insulating sheet 420, the gasket 310, the pressing block 320, the rear cover 330, and the fixing assembly 500, it can be first connected to the connector outside the mold and then connected to the capacitance measurement circuit.

[0056] The pressing block 320 is fixedly connected to the housing 100;

[0057] Both ends of the rear cover 330 are respectively inserted into the hollow spaces of the pressing block 320 and the fixing assembly 500, and are fixedly connected to the pressing block 320 and the fixing assembly 500; the fixing assembly 500 is fixedly connected to the mold.

[0058] As Figure 8 shown, in some embodiments of the present invention, one end of the pin 220 close to the fixing assembly 500 is provided with a first notch 222 along its axial direction. The first notch 222 continuously extends along the length direction of the pin 220, which is convenient for cooperating with a special tool to disassemble and assemble the cable.

[0059] In some embodiments of the present invention, the pole piece 210 is made of materials such as zirconia ceramics or alumina ceramics. Capacitance signals are sometimes very weak. Zirconia ceramics or alumina ceramics have good conduction characteristics and less attenuation of capacitance signals. The pole piece is designed in the shape of a rotating cylinder, and the head diameter of the pole piece is 1-8 mm, which can be applicable to a wider range of injection mold structure types. When the head diameter of the pole piece is small, a signal amplification circuit can be connected to the subsequent circuit to amplify the capacitance signal and improve the effectiveness and stability of the collected signal.

[0060] In some embodiments of the present invention, the pin receiving hole 211 of the pole piece 210 is provided with internal threads, the outer surface of the pin 220 is provided with external threads, and the pin 220 is threadedly connected to the pole piece 210.

[0061] As Figure 7 、 Figure 10 、 Figure 11As shown, in some embodiments of the present utility model, a first groove 212 and a second groove 311 are respectively provided at one ends of the pole piece 210 and the gasket 310 facing the second insulating sheet 420, and the inner diameters of the first groove 212 and the second groove 311 are both equal to the outer diameter of the second insulating sheet 420. As Figure 9 shown, chamfers are provided on both end faces of the second insulating sheet 420 to facilitate the assembly of the second insulating sheet 420 between the first groove 212 and the second groove 311.

[0062] In some embodiments of the present utility model, an external thread is provided on the outer surface of the pressing block 320, and an internal thread is provided at one end of the housing 100 close to the pressing block 320, and the pressing block 320 is threadedly connected to the housing 100.

[0063] In some embodiments of the present utility model, an internal thread is provided at one end of the pressing block 320 close to the rear cover 330, and an external thread is provided at one end of the rear cover 330 close to the pressing block 320, and the rear cover 330 is threadedly connected to the pressing block 320.

[0064] As Figures 12 - 14 shown, in some embodiments of the present utility model, the pressing block 320 includes a gasket connecting portion 321, a housing connecting portion 322 and a rear cover connecting portion 323. The diameter of the gasket connecting portion 321 is equal to the outer diameter of the gasket 310. The housing connecting portion 322 includes a threaded portion 3221 and a control portion 3222. The threaded portion 3221 is provided with an external thread, and the external thread is matched with the internal thread at one end of the housing 100 close to the pressing block. The control portion 3222 is equivalent to the head of the threaded portion 3221, which is convenient for cooperating with a tool to tighten or loosen the thread. In the assembled state, the threaded portion 3221 is completely screwed into the housing 100, and the control portion 3222 is located between the housing 100 and the fixing assembly 500. The rear cover connecting portion 323 is provided at one end of the pressing block 320 close to the control portion 3222 at the axial center position, and an internal thread is provided in the rear cover connecting portion 323, which is matched with the external thread on the rear cover 330.

[0065] In some embodiments of the present utility model, the fixing assembly 500 is a hollow nut, and concavo-convex structures are provided at one end of the rear cover 330 close to the hollow nut and at one end of the hollow nut close to the rear cover 330, and the rear cover 330 is connected to the hollow nut in a concavo-convex fit manner.

[0066] As Figures 15 - 17As shown, in some embodiments of the present utility model, the rear cover 330 includes a press block connection portion 331 and a fixing component connection portion 332. The press block connection portion 331 is provided with an external thread, which is in mating connection with the internal thread in the rear cover connection portion 323 in the press block 320. The fixing component connection portion 332 is provided with a concave-convex structure, and the concave-convex structure is in concave-convex mating connection with the hollow nut.

[0067] In some other embodiments, the rear cover 330, the press block 320 and the fixing component 500 can also be fixedly connected in other ways, and the present utility model does not limit this. For example, the rear cover 330 and the press block 320 are connected by concave-convex mating or interference fit, and the rear cover 330 and the fixing component 500 are connected by thread mating or interference fit.

[0068] As Figure 2 shown, in some embodiments of the present utility model, the hollow nut has a second notch 510 that runs through the entire axial length thereof. The second notch 510 continuously extends along the longitudinal center line of the nut, penetrating from the first end face of the nut to the second end face, facilitating the insertion of a special tool to achieve the disassembly and assembly of the cable and the rear cover 330. The present utility model does not particularly limit the width of the second notch.

[0069] In some embodiments of the present utility model, the outer diameter of the flange portion of the pole piece 210 is equal to the inner diameter of the flange portion of the first insulating sheet 410; the outer diameter of the flange portion of the first insulating sheet 410 is equal to the inner diameter of the flange portion of the housing 100; the length of the first insulating sheet 410 is equal to the length of the flange portion of the pole piece 210. Through the cooperation of the above dimensions, the tight connection of the housing 100, the first insulating sheet 410 and the pole piece 210 can be achieved.

[0070] In some embodiments of the present utility model, the outer surface of the pole piece 210 and the inner surface of the first insulating sheet 410 are fixed by a high-temperature resistant adhesive, and the outer surface of the first insulating sheet 410 and the inner surface of the housing 100 are fixed by a high-temperature resistant adhesive.

[0071] In some embodiments of the present utility model, potting glue is applied at the wire outlet of the rear cover 330. The potting glue plays a role in sealing and protecting.

[0072] As Figure 1As shown, the outer diameter of the pole piece flange part is 4 mm, the outer diameter of the housing flange part is 7.2 mm, the outer diameter of the housing rotating body part is 11 mm, the length of the housing is 20.5 mm, the length of the hollow nut is 35 mm, the end diameter of the hollow nut is 16 mm, the diameter of the threaded part of the hollow nut is 11 mm, the thickness of the control part of the pressure block is 1.95 mm, and the length of the assembled point-type capacitive sensor is about 57.45 mm. In practical applications, pole pieces of different sizes can be designed according to needs, and then the sizes of components such as the first insulating sheet and the housing can be adjusted accordingly.

[0073] The point-type capacitive sensor provided by the present utility model can be installed on the bottom plate of the moving mold side in a way similar to a thimble, and its pole piece and the metal plate on the stationary mold side form two poles of a capacitor. Or, the point-type capacitive sensor can also be installed on the stationary mold bottom plate, so that the pole piece therein and the metal plate on the moving mold side form two poles of a capacitor. The capacitance signal is led out of the mold through a cable, and then combined with a signal amplification circuit, a capacitance measurement circuit, etc. to realize the acquisition and processing of the capacitance signal, and the state of the melt in the mold cavity at each stage of the injection molding process is sensed by monitoring the change of the capacitance signal.

[0074] The following is the installation method of the point-type capacitive sensor provided by an embodiment of the present utility model:

[0075] (1) Probe assembly: Insert the pin into the electrode, and fixedly connect the pin and the cable connector outside the mold through a cable.

[0076] (2) Housing installation: Apply a high-temperature resistant adhesive on the outer surface of the electrode, and then sleeved and fixed the electrode in the first insulating sheet; apply a high-temperature resistant adhesive on the outer surface of the first insulating sheet, and then sleeved and fixed the first insulating sheet in the housing; the high-temperature resistant adhesive is resistant to high temperature of 300 °C.

[0077] (3) Guide assembly installation: Install the second insulating sheet, gasket, pressure block, and rear cover in sequence behind the electrode, and apply potting glue at the wire outlet of the rear cover.

[0078] (4) Baking: Put the assembled sensor into an incubator and bake it evenly at 80 - 100 °C for 2 - 3 hours until the above-mentioned high-temperature resistant adhesive and potting glue are fused with the relevant components to achieve an insulating and sealing effect.

[0079] (5) Mold installation: Install the baked sensor components in the mold through a fixing nut and fix them on the bottom plate of the moving mold side in a way similar to a thimble.

[0080] The utility model has the following beneficial effects: The dot-type capacitance sensor provided by the utility model comprises a housing, a first insulating sheet, a pole piece, a pin, a second insulating sheet, a gasket, a pressing block, a rear cover, and a fixing component; the first insulating sheet and the housing are sequentially sleeved outside the pole piece, the pin is fixed inside the pole piece, a wiring hole is arranged inside the pin, and a cable is sequentially passed through the second insulating sheet, the gasket, the pressing block, the rear cover, and the fixing component and then connected to a capacitance measurement circuit; the pressing sheet is fixedly connected to the housing, the rear cover is fixedly connected to the pressing block and the fixing component, and the fixing component is fixedly connected to a mold. The dot-type capacitance sensor provided by the utility model, compared with conventional sensors such as pressure sensors that can only detect single or partial parameters, can detect the change of the melt state in the mold cavity by collecting the capacitance signal of the dot-type capacitance sensor, realizing real-time monitoring and perception of each stage of the injection molding process; compared with a flat capacitor, it has a simple and compact structure, is convenient to install, and has a wider application range.

[0081] In addition, each component of the dot-type capacitance sensor provided by the utility model can achieve module standardization, and the production and manufacturing cost is lower, which is beneficial to the popularization and application in injection molds.

[0082] The embodiments of the utility model have been described above in conjunction with the accompanying drawings. However, the utility model is not limited to the above specific embodiments. The above specific embodiments are merely illustrative and not restrictive. Under the inspiration of the utility model, those of ordinary skill in the art can also make many forms of deformation without departing from the purpose of the utility model and the scope protected by the claims. All these fall within the protection scope of the utility model.

Claims

1. A point-type capacitive sensor, characterized in that: The sensor comprises a housing (100), a probe assembly (200), a guide assembly (300), an insulating assembly (400), and a fixing assembly (500); wherein: The probe assembly (200) comprises a pole piece (210) and a pin (220); The guide assembly (300) comprises a gasket (310), a pressing block (320), and a rear cover (330), and the guide assembly (300) is used to guide and fix the probe assembly (200); The insulating component (400) comprises a first insulating sheet (410) and a second insulating sheet (420), and the insulating component (400) is used to provide insulation protection for the probe component (200); The first insulating sheet (410) and the outer shell (100) are both hollow rotating bodies with an annular flange at one end; the pole piece (210) is a rotating body with a closed flange at one end; the first insulating sheet (410) and the outer shell (100) are sequentially sleeved and fixed outside the pole piece (210); The second insulating sheet (420), the gasket (310), the pressing block (320), the back cover (330), and the fixing assembly (500) are all hollow structures; A plug pin receiving hole (211) is provided on one side of the pole piece (210) close to the rotating body in the axial direction; the length of the plug pin receiving hole (211) is equal to the length of the plug pin (220); the plug pin (220) is fixed in the plug pin receiving hole (211); a wiring hole (221) is provided in the plug pin (220); a cable is connected to the wiring hole (221), passes through the second insulating sheet (420), the gasket (310), the pressure block (320), the back cover (330), the fixing assembly (500) in sequence, and is connected to the capacitance measurement circuit; The pressing block (320) is fixedly connected to the housing (100); The two ends of the rear cover (330) are respectively inserted into the hollow space between the pressing block (320) and the fixing assembly (500), and are fixedly connected to the pressing block (320) and the fixing assembly (500); the fixing assembly (500) is fixedly connected to the mold.

2. The point-type capacitive sensor according to claim 1, characterized in that: One end of the insertion pin (220) close to the fixing assembly (500) is provided with a first notch (222) along its axial direction.

3. The point-type capacitive sensor according to claim 1, characterized in that: The pin accommodating hole (211) of the pole piece (210) is provided with an internal thread, the outer surface of the pin (220) is provided with an external thread, and the pin (220) is threadedly connected to the pole piece (210).

4. The point-type capacitive sensor according to claim 1, characterized in that: The pole piece (210) and the gasket (310) are respectively provided with a first groove (212) and a second groove (311) at one end facing the second insulating sheet (420); the inner diameters of the first groove (212) and the second groove (311) are both equal to the outer diameter of the second insulating sheet (420).

5. The point-type capacitive sensor according to claim 1, characterized in that: The outer surface of the pressing block (320) is provided with an external thread, and one end of the outer shell (100) close to the pressing block (320) is provided with an internal thread, and the pressing block (320) is threadedly connected to the outer shell (100).

6. The point-type capacitive sensor according to claim 1, characterized in that: An end of the pressing block (320) close to the rear cover (330) is provided with an internal thread, and an end of the rear cover (330) close to the pressing block (320) is provided with an external thread, and the rear cover (330) is threadedly connected to the pressing block (320).

7. The point-type capacitive sensor according to claim 1, characterized in that: The fixing assembly (500) is a hollow nut, and an end of the rear cover (330) close to the hollow nut and an end of the hollow nut close to the rear cover (330) are both provided with a concave-convex structure, and the rear cover (330) is connected to the hollow nut in a concave-convex matching manner.

8. The point-type capacitive sensor according to claim 7, characterized in that: The hollow nut has a second notch (510) extending throughout its entire axial length.

9. The point-type capacitive sensor according to claim 1, characterized in that: The outer diameter of the flange portion of the pole piece (210) is equal to the inner diameter of the flange portion of the first insulating piece (410); the outer diameter of the flange portion of the first insulating piece (410) is equal to the inner diameter of the flange portion of the housing (100); and the length of the first insulating piece (410) is equal to the length of the flange portion of the pole piece (210).

10. The point-type capacitive sensor according to claim 1, characterized in that: The outer surface of the pole piece (210) and the inner surface of the first insulating sheet (410) are fixed via a high temperature resistant adhesive, and the outer surface of the first insulating sheet (410) and the inner surface of the housing (100) are fixed via a high temperature resistant adhesive.

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