Piston magnetizer position detection device
By using a piston-magnetic conductor position detection device, the piston drives the magnetic conductor to move within the coil, solving the problems of large size and inability to position existing detection devices, and achieving rapid and convenient detection within a compact structure.
Patent Information
- Application Number
- CN202510164930.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-02-14
- Publication Date
- 2026-03-03
AI Technical Summary
Existing detection devices are large in size, making them inconvenient to manufacture and design, and cannot be used in a compact structure. Furthermore, they can only detect the presence or absence of an object, but cannot obtain its specific location.
A piston-magnetic conductor position detection device was designed, including a housing, a piston, a magnetic conductor, and a coil. The piston drives the magnetic conductor to move in the coil, and the specific position of the object under test is detected by the change of inductance or resonant frequency. The device is miniaturized and does not require temporary assembly.
It enables rapid and convenient detection within a compact structure, accurately locates the position of the object being measured, and is compact, easy to manufacture and design.
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Figure CN121594735A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to a detection device, and more particularly to a piston magnetic conductor position detection device. Background Technology
[0002] To detect the presence of the analyte, existing technology uses... Figure 1 As shown, the switch test probe assembly 200 is mounted on the slider 300, which is mounted on the front end of the push rod of the cylinder 100. The switch test probe assembly 200 has a needle core 210, a tail needle 220, an insulator 230, and an outer sleeve 240. The outer sleeve 240 is fixed to the slider 300 and has a central hole 241. The needle core 210 and the tail needle 220 are inserted into the central hole 241. The rear end of the needle core 210 and the front end of the tail needle 220 are located inside the central hole 241, and a spring 250 is provided between them. The front end of the needle core 210 and the rear end of the tail needle 220 extend out of the central hole 241, and the needle core 210 contacts the outer sleeve 240. An insulator 230 is provided between the tail needle 220 and the outer sleeve 240.
[0003] In the prior art, both the tail needle 220 and the outer sleeve 240 are connected to the detection circuit (not shown in the figure) via wires. When the cylinder 100 pushes the slider 300, the switch test needle assembly 200 moves forward and approaches the object under test 400. The needle core 210 is compressed backward, so that the needle core 210 touches the tail needle 220. Since the outer sleeve 240, the needle core 210, and the tail needle 220 are all conductive objects, the needle core 210 makes the tail needle 220 and the outer sleeve 240 conductive, thus forming a circuit, thereby proving the existence of the object under test 400.
[0004] It is easy to see that existing technologies are large in size, inconvenient to process and design, require temporary assembly, cannot be used in compact structures, and can only detect the presence or absence of an object, not its specific position. Therefore, improvement is necessary. In view of this, the inventor, drawing on extensive experience accumulated over many years in the field of detection devices, conducted in-depth research on existing detection devices and developed a piston magnetic conductor position detection device, thus giving rise to this invention. Summary of the Invention
[0005] The purpose of this invention is to provide a piston magnetic conductor position detection device that is miniaturized, convenient for processing and design, requires no temporary assembly, can be used in a compact structure, and can obtain the specific position of the object being measured, making detection convenient and fast.
[0006] To achieve the above objectives, the solution of the present invention is:
[0007] A piston-magnetic conductor position detection device includes a housing, a piston, a magnetic conductor, and a coil. Openings are formed at both the front and rear ends of the housing. A piston, which moves under the action of a driving force, is located at the front end of the housing. A piston return spring is positioned between the housing and the piston. A test head for detecting the object under test is located at the front end of the piston, extending from the opening at the front end of the housing. The magnetic conductor is fixed at the rear end of the piston. A coil is installed at the rear end of the housing. The magnetic conductor passes through the coil and moves within the coil, driven by the piston. In use, when the driving force acts on the piston, the piston compresses the piston return spring, causing it to move. Simultaneously, the piston moves the magnetic conductor. As the magnetic conductor moves within the coil, the inductance of the coil changes. By measuring the inductance or resonant frequency change of the coil using a detector, the specific position of the magnetic conductor can be obtained, thus determining the specific position of the object under test.
[0008] Furthermore, the object to be tested by the device is fixed. An air inlet is provided on the outer shell to allow compressed air to enter the shell and drive the piston to move. The driving force for the piston to move is the compressed air entering the shell through the air inlet. A sealing ring is provided between the piston and the shell to ensure airtightness. Under normal conditions, the piston return spring causes the piston and the test head to move back into the shell to reset. The piston moves forward under the action of compressed air, driving the test head forward until it touches the object to be tested.
[0009] Furthermore, the device targets a moving object, and the piston generates a driving force for the moving object. Under normal conditions, the piston return spring causes the piston and test head to move and reset towards the front end of the housing, and the piston moves backward under the action of the moving object.
[0010] In one optimized design, the front end of the piston forms a push rod, and the front end of the push rod directly forms a test head, such as a flat test head or a hemispherical test head. Alternatively, in another optimized design, the front end of the piston is equipped with a spherical test head, and the diameter of the front opening of the outer shell is smaller than the diameter of the spherical test head. Most of the test head is confined within the outer shell, while a small portion protrudes from the front opening. Yet another optimized design involves the front end of the piston forming a push rod with internal threads, allowing connection to various test heads to accommodate different test objects.
[0011] Furthermore, a circuit board is installed at the rear of the housing, and the coil leads are connected to the circuit board.
[0012] Furthermore, the circuit board extends from the side of the housing; or, the circuit board extends along the axial direction of the housing.
[0013] Furthermore, the rear section of the housing is fixed with a coil bracket, the rear end of the coil bracket is fixed with a circuit board, and the coil is mounted on the coil bracket; or, the rear section of the housing is fixed with a coil bracket, the rear end of the coil bracket is fixed with a circuit board, the coil is mounted on the coil bracket, a base is added between the coil bracket and the circuit board, the front side of the base is fixed to the coil bracket and the rear side is fixed with the circuit board, the base forms an extension tube corresponding to the center hole of the coil bracket for the magnetic conductor to extend into, the extension tube is inserted into the center hole of the coil bracket and abuts against the coil to fix the coil; or, the rear section of the housing is fixed with a bushing, a tailstock and an insulating sleeve, the coil is fixed in the housing by means of the bushing and the tailstock, and the circuit board is fixed in the housing by means of the insulating sleeve.
[0014] Furthermore, the front opening of the outer shell is constricted, while the rear opening is open; the rear end of the outer shell is covered with an insulating wrapping body, which fixes the coil and the circuit board to the rear end of the outer shell, and the insulating wrapping body forms a circuit board through hole corresponding to the circuit board; or the insulating wrapping body forms an air nozzle corresponding to the air inlet of the outer shell.
[0015] Furthermore, a capacitor is connected in parallel to both ends of the coil leads on the circuit board, and the capacitor is soldered to the circuit board, forming an LC oscillator with the coil; alternatively, a capacitor is connected in parallel to both ends of the coil leads, and a test instrument is also connected in parallel; the capacitor can eliminate the influence of the connection line between the test instrument and this device, allowing the coil to have a stable resonant frequency. Alternatively, the test instrument is connected in parallel to both ends of the coil leads. Alternatively, the circuit board also has pads for connecting external leads to the test instrument.
[0016] By adopting the above solution, this invention integrates the magnetic conductor and the testing component, eliminating the need for an external cylinder. During use, air can be supplied simply by connecting the air inlet to an air pump; when not in use, the connection can be removed. The overall size of the device is greatly reduced, facilitating processing and design. It eliminates the need for temporary assembly of a large cylinder, allowing for use within a compact structure and making operation very convenient and quick. Furthermore, when the driving force acts on the piston, the magnetic conductor, driven by the piston, moves within the coil, causing a change in the coil's inductance. By measuring the coil's inductance or the change in the resonant frequency formed by the capacitor with a detector, the specific position of the magnetic conductor can be obtained, thus revealing the specific position of the object under test.
[0017] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. Attached Figure Description
[0018] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments are briefly described below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained from these drawings without creative effort.
[0019] Figure 1 This is a three-dimensional exploded view of the existing detection device;
[0020] Figure 2 This is a structural schematic diagram of Embodiment 1 of the present invention;
[0021] Figure 3 This is a schematic diagram of the structure of Embodiment 2 of the present invention;
[0022] Figure 4 This is a schematic diagram of the structure of Embodiment 3 of the present invention;
[0023] Figure 5 This is a schematic diagram of the structure of Embodiment 4 of the present invention;
[0024] Figure 6 This is a structural schematic diagram of Embodiment 5 of the present invention;
[0025] Figure 7 This is a schematic diagram of the structure of Embodiment Six of the present invention;
[0026] Figure 8 This is a schematic diagram of the structure of Embodiment Seven of the present invention;
[0027] Figure 9 This is a structural schematic diagram of Embodiment 8 of the present invention.
[0028] Label Explanation
[0029] 100----Cylinder, 200----Switch test probe assembly, 210----Needle core, 220----Tail needle, 230----Insulator, 240----Outer jacket, 241----Center hole, 250----Spring, 300----Slider, 400----Object under test;
[0030] 1----Outer shell, 11----Air inlet, 12----Sealing ring, 13----Step;
[0031] 2----piston, 21----piston return spring, 22----internal thread;
[0032] 3----Magnetic conductor;
[0033] 4----coil, 41----shroud, 42----tailstock;
[0034] 5----Test Head;
[0035] 6----coil bracket, 61----positioning post;
[0036] 7----Circuit board, 71----Insulating sleeve;
[0037] 8----Insulation wrapping, 81----Air nozzle, 82----Circuit board perforation;
[0038] 9----base, 91----extension tube, 92----positioning post. Detailed Implementation
[0039] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, not all of them. Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to represent selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.
[0040] It should be noted that the terms front, back, inside, outside, top, bottom, left, right, first, second, third, etc. are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the technical features indicated, unless otherwise explicitly defined.
[0041] This article defines the direction closer to the inspection station as "front" and the direction farther from the inspection station as "back". The terms "front" and "back" are only relative positions and are used to facilitate the description of the structure, not as a limitation on the technical solution. The front and back can be interchanged without affecting the overall structure.
[0042] like Figures 2 to 9 As shown, the present invention discloses a piston magnetic conductor position detection device, including a housing 1, a piston 2, a magnetic conductor 3, and a coil 4.
[0043] The front and rear ends of the outer shell 1 are respectively formed with openings.
[0044] A piston 2 is provided at the front end of the outer casing 1. The piston 2 moves under the action of a driving force, which can be from the inside of the outer casing 1 to the outside or from the outside to the inside of the outer casing 1. A piston return spring 21 is provided between the outer casing 1 and the piston 2. The front end of the piston 2 has a test head 5, which extends from the front opening of the outer casing 1. The test head 5 is used to detect the object under test 400.
[0045] The piston 2 has a fixed magnetic conductor 3 at its rear end, such as iron, nickel-iron alloy, manganese-zinc alloy, nickel-zinc alloy, ferrite, etc.
[0046] The rear section of the outer casing 1 is fixed with a coil bracket 6, and the rear end of the coil bracket 6 is fixed with a circuit board 7. Specifically, the coil bracket 6 can be fixed to the circuit board 7 by two positioning posts 61. The coil 4 is mounted on the coil bracket 6, and the lead wire of the coil 4 is connected to the circuit board 7. Of course, the present invention can also directly fix the coil 4 and the circuit board 7 at the rear section of the outer casing 1, omitting the coil bracket 6, which is not shown in the figure.
[0047] The magnetic conductor 3 is inserted into the coil 4, and the piston 2 drives the magnetic conductor 3 to move within the coil 4.
[0048] Furthermore, this invention allows for the parallel connection of a capacitor (a common component, not shown in the figure) across both ends of the coil 4 leads on the circuit board 7. The capacitor is soldered onto the circuit board 7, and the capacitor and coil 4 form an LC oscillator, eliminating the influence of the connection lines between the detector and this device, thus enabling coil 4 to have a stable resonant frequency. Additionally, this invention further includes solder pads (a common component, not shown in the figure) on the circuit board 7 for connecting external leads to the tester, facilitating testing.
[0049] In operation, circuit board 7 is directly connected to the detection circuit (not shown in the figure), making the connection more convenient and faster. When the driving force is applied to piston 2, piston 2 compresses piston return spring 21 to generate movement. The moving piston 2 simultaneously drives the magnetic conductor 3 to move as well. When the magnetic conductor 3 moves in coil 4, the inductance of coil 4 changes. By measuring the inductance value of coil 4 or the change in the resonant frequency formed by coil 4 and capacitor with a detector, the specific position of magnetic conductor 3 can be obtained, thereby obtaining the specific position of the object under test 400.
[0050] like Figure 2 As shown, the test object 400 of the device described in Embodiment 1 of the present invention is fixed. An air inlet 11 is provided on the outer casing 1 to allow compressed air to enter the casing 1 and drive the piston 2. The driving force for the piston 2 to move is the compressed air entering the casing 1 through the air inlet 11. A sealing ring 12 (O-ring or V-ring) can be further provided between the piston 2 and the casing 1 to ensure airtightness, thereby ensuring the effective action of compressed air on the piston 2 during operation. Under normal conditions, the piston return spring 21 causes the piston 2 and the test head 5 to move back into the casing 1. Under the action of compressed air, the piston 2 squeezes the piston return spring 21 and moves forward, driving the test head 5 forward until it touches the test object 400.
[0051] In Embodiment 1, the front end of the piston 2 forms a push rod, which directly serves as the test head 5. Alternatively, the push rod may have an internal thread 22 for connecting various test heads (not shown in the figure) to accommodate different test objects 400.
[0052] For ease of assembly, the front opening of the outer shell 1 in Embodiment 1 is constricted, while the rear opening is open. The two ends of the piston return spring 21 abut against the front end of the outer shell 1 and the front end of the piston 2. The rear end of the outer shell 1 is covered with an insulating wrapper 8, which fixes the coil 4, coil support 6 and circuit board 7 to the rear end of the outer shell 1. Alternatively, a step 13 can be formed in the outer shell 1, which, together with the insulating wrapper 8, fixes the coil 4, coil support 6 and circuit board 7. The insulating wrapper 8 further forms an air nozzle 81 corresponding to the air inlet 11 of the outer shell 1, and a circuit board through hole 82 corresponding to the circuit board 7.
[0053] In the first embodiment, air is supplied by connecting the air inlet 11 to the air pump. Compressed air is delivered to the outer casing 1 through the air inlet 11. The piston 2 is pushed forward by the compressed air to move towards the test object 400. The piston 2 moves along with the magnetic conductor 3 and the test head 5. When the test head 5 touches the test object 400, it stops moving. At the same time, the magnetic conductor 3, which is moved along with the piston 2, moves in the coil 4, causing a change in the inductance of the coil 4. By measuring the change in the inductance or resonant frequency of the coil 4 with a detector, the specific position of the magnetic conductor 3 can be obtained, thereby obtaining the specific position of the test object 400.
[0054] Also, such as Figure 3 As shown, in Embodiment 2 of the present invention, the test object 400 is also fixed, similar to that in Embodiment 1. The driving force for the piston 2 to move is compressed air entering the outer casing 1 through the air inlet 11. The main structures of Embodiment 1 and Embodiment 2 are the same, except that in Embodiment 2, the coil 4 is shorter, while the length of the outer casing 1 is the same as in Embodiment 1. Therefore, a base 9 is added between the coil support 6 and the circuit board 7. The front side of the base 9 is fixed to the coil support 6, and the rear side is fixed to the circuit board 7. Specifically, the coil support 6 and the base 9 can be fixed by two positioning posts 61, and the base 9 and the circuit board 7 can also be fixed by two positioning posts 92. The base 9 forms an extension tube 91 corresponding to the central hole of the coil support 6 for the insertion of the magnetic conductor 3. The extension tube 91 is inserted into the central hole of the coil support 6 and abuts against the coil 4 to fix the coil 4. The coil 4, coil support 6, base 9, and circuit board 7 are then fixed to the rear end of the outer casing 1 by means of the insulating wrapping body 8. Similar to Embodiment 1, this second embodiment also forms a step 13 in the outer casing 1. The step 13, together with the insulating wrapping body 8, fixes the coil 4, coil support 6, base 9 and circuit board 7.
[0055] The working principle of Example 2 is the same as that of Example 1, and will not be repeated here.
[0056] Furthermore, such as Figure 4 As shown, the device described in Embodiment 3 of the present invention targets a test object 400 that moves horizontally, with the direction of movement indicated by the arrow. The piston 2 generates the driving force for the movement of the test object 400 outside the outer casing 1. Under normal conditions, the piston return spring 21 causes the piston 2 and the test head 5 to move back to the front end of the outer casing 1. Under the action of the moving test object 400, the piston 2 moves backward (inside the outer casing 1). Specifically, the front end of the piston 2 forms a push rod, which directly serves as the test head 5. Alternatively, the push rod may have internal threads for connecting various test heads (not shown in the figure) to accommodate different test objects 400. The front opening of the outer casing 1 is constricted, while the rear opening is open. The two ends of the piston return spring 21 abut against the piston 2 and the coil support 6. The rear end of the outer casing 1 is covered with an insulating wrapping body 8, which fixes the coil 4, the coil support 6 and the circuit board 7 to the rear end of the outer casing 1. Alternatively, a step 13 can be formed in the outer casing 1, which, together with the insulating wrapping body 8, fixes the coil 4, the coil support 6 and the circuit board 7. The insulating wrapping body 8 further forms a circuit board through hole 82 corresponding to the circuit board 7.
[0057] In Example 3, the test head 5 is first brought into contact with the object under test 400. When the object under test 400 moves horizontally, it pushes the piston 2 into the outer shell 1. The piston 2 squeezes the piston return spring 3. At the same time, the piston 2 drives the magnetic conductor 3 to move together. When the magnetic conductor 3 moves in the coil 4, it causes the inductance of the coil 4 to change. By measuring the inductance or resonant frequency change of the coil 4 with a detector, the specific position of the magnetic conductor 3 can be obtained, thereby obtaining the specific position of the object under test 400.
[0058] Additionally, such as Figure 5 and Figure 6 As shown, the devices described in Embodiments 4 and 5 of the present invention target test objects 400 that move vertically, with the direction of movement as indicated by the arrows. The driving force generated by the piston 2 is the moving test object 400 outside the outer casing 1. Embodiments 4 and 5 have the same main structure as Embodiment 3, the difference being that: in Embodiment 4, the front end of the piston 2 forms a push rod, and the front end of the push rod directly forms a hemispherical test head 5; in Embodiment 5, the front end of the piston 2 is equipped with a spherical test head 5, the diameter of the front opening of the outer casing 1 is smaller than the diameter of the spherical test head 5, most of the test head 5 is confined in the outer casing 1 and will not come out, while a small part of the test head 5 protrudes from the front opening of the outer casing 1. The hemispherical test head 5 in Embodiment 4 and the spherical test head 5 in Embodiment 5 can reduce the frictional force between the test object 400 and the moving test object, making the testing work smoother.
[0059] The working principle of Examples 5 and 6 is similar to that of Example 3. First, the test head 5 touches the object under test 400. When the object under test 400 moves vertically downward, it pushes the piston 2 into the outer shell 1. The piston 2 squeezes the piston return spring 3. At the same time, the piston 2 drives the magnetic conductor 3 to move together. When the magnetic conductor 3 moves in the coil 4, it causes the inductance of the coil 4 to change. By measuring the inductance or resonant frequency change of the coil 4 with the detector, the specific position of the magnetic conductor 3 can be obtained, thereby obtaining the specific position of the object under test 400.
[0060] Also, such as Figures 7 to 9 As shown, the devices described in embodiments six, seven, and eight of this invention are similar to those in embodiment three, all targeting a horizontally moving test object 400, with the direction of movement as indicated by the arrows. The piston 2 generates the driving force for the movement of the test object 400 outside the outer casing 1. Under normal conditions, the piston return spring 21 causes the piston 2 and the test head 5 to move back towards the front end of the outer casing 1. Under the action of the moving test object 400, the piston 2 moves backward (inside the outer casing 1). Specifically, the front end of the piston 2 forms a push rod, which directly serves as the test head 5. Figures 7 to 9 Three different test heads 5 are shown to accommodate different test objects 400. One end of the piston return spring 21 rests against the piston 2, and the other end rests directly or indirectly against the housing 1. As shown in the figure, the coil 4 is fixed in the housing 1 by means of a bushing 41 and a tailstock 42. The bushing 41 guides the magnetic conductor 3, allowing it to enter the coil 4 more accurately. The circuit board 7 is fixed in the housing 1 by means of an insulating sleeve 71, and the other end of the piston return spring 21 rests against the bushing 41 (i.e., indirectly against the housing 1).
[0061] The working principle of Examples 6, 7, and 8 is the same as that of Example 3. After the test head 5 touches the test object 400, the test object 400 moves horizontally and pushes the piston 2 into the outer shell 1. The piston 2 squeezes the piston return spring 21. At the same time, the piston 2 drives the magnetic conductor 3 to move together. When the magnetic conductor 3 moves in the coil 4, it causes the inductance of the coil 4 to change. By measuring the inductance or resonant frequency change of the coil 4 with the detector, the specific position of the magnetic conductor 3 can be obtained, thereby obtaining the specific position of the test object 400.
[0062] It should be noted that the circuit board 7 can also be omitted in this invention, and the coil 4 can be directly connected to the detection circuit through the lead wire. Its working principle is the same as that of the aforementioned embodiments, and will not be illustrated or described in detail here.
[0063] The different extension methods of the circuit board 7 described in this invention can be applied to work surfaces of different sizes. In embodiments one to five, the circuit board 7 extends from the side of the outer casing 1. In embodiments six to eight, the circuit board 7 extends along the axial direction of the outer casing 1, making the overall width slender, the structure more compact, the work surface smaller, and adapting to the miniaturization requirements of the test module.
[0064] The embodiments described above are merely illustrative of the technical ideas and features of the present invention, and are intended to enable those skilled in the art to understand the content of the present invention and implement it accordingly. However, they do not limit the patent scope of the present invention. All equivalent changes or modifications made in accordance with the spirit disclosed in the present invention should still be covered within the patent scope of the present invention.
Claims
1. A piston magnet position detection device, characterized in that: It includes a housing, a piston, a magnetic conductor, and a coil; the front and rear ends of the housing are respectively formed with openings; the front section of the housing is provided with a piston that moves under the action of driving force, and a piston return spring is provided between the housing and the piston. The front end of the piston has a test head for detecting the object under test, and the test head extends out from the front opening of the housing. The rear end of the piston is fixed with a magnetic conductor; the rear section of the housing is equipped with a coil; the magnetic conductor passes through the coil and is driven by the piston to move in the coil, causing the inductance of the coil to change.
2. The piston magnetic conductor position detection device according to claim 1, characterized in that: The device targets a fixed object. An air inlet is provided on the outer shell to allow compressed air to enter the shell and drive the piston. The driving force for the piston to move is the compressed air entering the shell through the air inlet. A sealing ring is provided between the piston and the shell to ensure airtightness. Under normal conditions, the piston return spring moves the piston and the test head back into the shell to reset. The piston moves forward under the action of compressed air, driving the test head forward until it touches the object being tested.
3. The piston magnet position detection device according to claim 1, characterized in that: The device targets a moving object, and the piston generates a driving force for the moving object. Under normal conditions, the piston return spring moves the piston and test head back to the front end of the housing, and the piston moves backward under the action of the moving object.
4. A piston magnet position detection device according to claim 2 or 3, characterized in that: The piston has a push rod at its front end, and the front end of the push rod directly forms a planar test head or a hemispherical test head; or, the piston has a push rod at its front end, and the push rod has an internal thread that connects to the test head.
5. The piston magnet position detection device according to claim 3, characterized in that: The piston is equipped with a spherical test head at its front end. The diameter of the front opening of the outer shell is smaller than the diameter of the spherical test head. Most of the test head is confined in the outer shell, while a small part protrudes from the front opening of the outer shell.
6. A piston magnet position detection device according to claim 1, 2 or 3, characterized in that: A circuit board is also installed at the rear of the housing, and the coil leads are connected to the circuit board.
7. The piston magnet position detection device according to claim 6, characterized in that: The front opening of the outer casing is constricted, while the rear opening is open. The rear end of the outer casing is covered with an insulating wrapping material, which fixes the coil and the circuit board to the rear end of the outer casing. The insulating wrapping material forms a circuit board through-hole corresponding to the circuit board. Alternatively, the front opening of the outer casing is constricted, while the rear opening is open; the rear end of the outer casing is covered with an insulating wrapping body, which fixes the coil and circuit board to the rear end of the outer casing. The insulating wrapping body forms a circuit board through-hole corresponding to the circuit board, and the insulating wrapping body forms an air nozzle corresponding to the air inlet of the outer casing.
8. The piston magnet position detection device according to claim 6, characterized in that: The circuit board extends from the side of the housing; or, the circuit board extends along the axial direction of the housing.
9. A piston magnet position detection device according to claim 6, characterized in that: The rear section of the housing is fixed with a coil bracket, and the rear end of the coil bracket is fixed with a circuit board. The coil is mounted on the coil bracket. Alternatively, the rear section of the housing is fixed with a coil bracket, the rear end of the coil bracket is fixed with a circuit board, the coil is mounted on the coil bracket, a base is added between the coil bracket and the circuit board, the front side of the base is fixed to the coil bracket and the rear side is fixed with the circuit board, the base forms an extension tube corresponding to the center hole of the coil bracket for the magnetic conductor to extend into, the extension tube is inserted into the center hole of the coil bracket and abuts against the coil to fix the coil. Alternatively, the rear section of the housing is fixed with a bushing, a tailstock and an insulating sleeve, the coil is fixed in the housing by means of the bushing and the tailstock, and the circuit board is fixed in the housing by means of the insulating sleeve.
10. A piston magnet position detection device according to claim 6, characterized in that: A capacitor is connected in parallel to both ends of the coil lead on the circuit board, and the capacitor is soldered to the circuit board. The capacitor and the coil form an LC oscillator; or, a capacitor is connected in parallel to both ends of the coil lead, and a tester is also connected in parallel; or, a tester is connected in parallel to both ends of the coil lead; or, the circuit board also has pads connected to the coil lead for soldering external leads to connect to the tester.