Eddy current type sensor
By designing contact eddy current sensors, using Halbach magnetic arrays and highly conductive non-magnetic cylinders, combined with sharp knife-shaped metal probes and coils, the problem that traditional eddy current sensors can only measure metal conductors, and the problem of any material being Accurate measurement of objects improves measurement accuracy and sensitivity.
Patent Information
- Application Number
- CN202420973250.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-05-08
- Publication Date
- 2025-02-21
- Estimated Expiration
- 2034-05-08
AI Technical Summary
Traditional eddy current sensors can only accurately measure the static and dynamic relative displacement changes of metal conductors and cannot be suitable for the objects to be measured in non-metallic materials.
A contact eddy current sensor is designed, using Halbach magnetic array permanent magnets and highly conductive non-magnetic cylinders to form an eddy current module. Combined with a sharp knife-like metal probe and coil, it can measure the displacement or vibration of the measured object of any material.
It improves the accuracy and sensitivity of the sensor, expands the range of test objects, and makes the test data more accurate. At the same time, the structure is simple, the working principle is simple, and it is easy to use.
Smart Images
Figure CN222514336U_ABST
Abstract
Description
Technical Field
[0001] The utility model discloses an eddy current sensor and relates to the technical field of testing. Background Art
[0002] In scientific research experiments, testing technology is a very important technology, and the existence of sensors makes testing more accurate and convenient. It allows objects to have senses such as touch, taste and smell. It can be said that sensors are an extension of human five senses.
[0003] A sensor is a detection device that can convert measurements into corresponding outputs in other forms, such as electrical, pneumatic, hydraulic, etc. The characteristics of sensors include: miniaturization, digitization, intelligence, multi-function, systematization, and networking. It is the primary link in achieving automatic detection and automatic control. In a narrow sense, a sensor can be defined as "a device or device that converts non-electrical input from the outside into corresponding electrical output."
[0004] In today's society, there are many types of sensors, including resistive sensors, capacitive sensors, inductive sensors, piezoelectric sensors, photoelectric sensors, Hall sensors, etc. Different sensors have different working principles.
[0005] The eddy current sensor is a sensor that uses the principle of electromagnetic induction for testing. It can statically and dynamically measure the distance between the metal conductor being tested and the probe surface. However, the eddy current sensor can only accurately measure the static and dynamic relative displacement changes between the metal conductor and the probe end face. In actual measurement, not all objects being tested are metal conductors. Therefore, the utility model proposes a contact eddy current sensor, whose object being tested can be any material, solving the limitations of the objects being tested by traditional eddy current sensors. Utility Model Content
[0006] The utility model aims to provide an eddy current sensor to solve the limitations of the prior art.
[0007] In order to achieve the above purpose, the utility model provides the following technical solutions:
[0008] The utility model provides an eddy current sensor, comprising an eddy current module, the eddy current module comprising a permanent magnet and a highly conductive non-magnetic cylinder; a measuring module, the measuring module comprising a coil and a metal probe; and a shell.
[0009] The eddy current module includes at least 8 permanent magnets and 1 highly conductive non-magnetic cylinder. The permanent magnets are arranged in a circle according to the magnetization direction of the Halbach magnetic array. The strong magnetic field of the Halbach magnetic array is distributed inside the circle, and the weak magnetic field is distributed outside the circle.
[0010] Furthermore, the highly conductive non-magnetic cylinder has the same length as the permanent magnet and is disposed outside the permanent magnet to provide necessary structural strength to support lateral force.
[0011] Furthermore, the metal probe is made of highly conductive non-magnetic metal, and the working end of the metal probe is in the shape of a sharp knife and is built into the housing. During testing, the metal probe cuts the magnetic flux lines to generate an induced electromotive force, thereby generating an induced current.
[0012] Furthermore, the fixed end of the metal probe is used to connect to the object to be measured, and the object to be measured can be an object of any material.
[0013] Furthermore, the coil is arranged at the interface between the housing and the metal probe, and is used to measure the magnitude of the induced current.
[0014] Compared with the traditional eddy current sensor, the improvements of the utility model are:
[0015] The permanent magnets described in the present application are arranged in a circle in the direction of magnetization of the Halbach magnetic array, and the magnetic flux lines of the strong magnetic field inside the circle are in one direction and evenly distributed. When the fixed end of the metal probe is fixed to the object to be measured, the displacement or vibration of the metal probe is driven by the displacement or vibration of the object, and the working end of the metal probe cuts the magnetic flux lines. According to Lenz's law, the changing magnetic field produces a changing induced electromotive force, and the induced electromotive force produces an induced current. The magnitude of the induced current is measured by the coil, and the magnitude of the displacement or vibration can be obtained. In the present application, the improved eddy current sensor is a contact sensor, and its accuracy and sensitivity will be improved. While expanding the range of test objects, it also makes the test data more accurate. BRIEF DESCRIPTION OF THE DRAWINGS
[0016] Figure 1 This is a schematic diagram of the internal structure of an eddy current sensor of the utility model;
[0017] Figure 2 This is a schematic diagram of the Halbach magnetization direction of an eddy current sensor of the utility model;
[0018] Figure 3 This is a schematic diagram of the working end of a metal probe of an eddy current sensor of the utility model;
[0019] Figure 4 This is a schematic diagram of an eddy current module of an eddy current sensor of the utility model;
[0020] Figure 5 This is a schematic diagram of an eddy current sensor coil of the utility model
[0021] In the figure, 1 is a housing; 2 is an eddy current module; 21 is a highly conductive non-magnetic cylinder; 22 is a permanent magnet; 31 is a metal probe; 32 is a coil; 311 is a working end of the metal probe. DETAILED DESCRIPTION
[0022] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.
[0023] like Figure 1 , 2 , 3 and Figure 4 As shown, an eddy current sensor includes a housing 1, a highly conductive non-magnetic cylinder 21, a permanent magnet 22 and a metal probe 3, wherein the highly conductive non-magnetic cylinder 21 and the permanent magnet 22 constitute an eddy current module 2.
[0024] In this embodiment, the number of permanent magnets 22 is 8, and the length and thickness are the same. When k = 2, the magnetic field within the circumference of the Halbach magnetic array is uniform, so the magnetization angle can be calculated as Therefore, the magnetization direction is Figure 2 shown.
[0025] Furthermore, the circular array formed by the permanent magnet 22 is embedded into the highly conductive non-magnetic cylinder 21 to form the eddy current module 2 of the eddy current sensor, as shown in FIG. Figure 4 In the present application, the highly conductive non-magnetic cylinder 21 is an aluminum ring, the length of which is consistent with the length of the permanent magnet 22, providing the necessary structural strength for the circumferential array to support the lateral force.
[0026] like Figure 3As shown, the working end 311 of the metal probe used in the present application is in the shape of a sharp knife, and the tip of the sharp knife is tangent to the circular array formed by the permanent magnet 22. When the object to be measured passes through the fixed end of the metal probe 3 to cause the metal probe 3 to be displaced or vibrated, the working end 311 will cut the magnetic flux lines. According to Lenz's law, the changing magnetic field produces a changing induced electromotive force, and the induced electromotive force produces an induced current. Further, the coil 32 is arranged at the interface between the housing 1 and the metal probe 31, and is used to measure the induced current of the metal probe 3. Thus, the induced current of the metal probe 31 can be measured by the coil 32, and then the displacement or vibration size of the object can be detected. The eddy current sensor of the present application is a contact sensor, which is more accurate than the traditional eddy current sensor belonging to the non-contact sensor, and the measurement data is more accurate. In addition, the present application has a simple structure, a simple working principle, and is easy to use.
[0027] The above-described embodiment only expresses one implementation method of the utility model and cannot be understood as limiting the scope of the utility model patent. For example, if the displacement or amplitude of the measured object is large, the length of the permanent magnet, the highly conductive non-magnetic cylinder and the working end of the metal probe can be appropriately increased to increase the measurement range of the eddy current sensor.
[0028] It should be pointed out that, for those skilled in the art, several modifications and improvements can be made without departing from the concept of the utility model, and these are all within the scope of protection of the utility model. Therefore, the scope of protection of the utility model patent shall be based on the attached claims.
Claims
1. An eddy current sensor, comprising an eddy current module, the eddy current module comprising a permanent magnet and a highly conductive non-magnetic cylinder; a measuring module, the measuring module comprising a coil and a metal probe; and a housing; The eddy current module includes at least 8 permanent magnets and 1 highly conductive non-magnetic cylinder. The permanent magnets are arranged in a circle according to the magnetization direction of the Halbach magnetic array. The strong magnetic field of the Halbach magnetic array is distributed inside the circle, and the weak magnetic field is distributed outside the circle.
2. An eddy current sensor according to claim 1, characterized in that: The highly conductive non-magnetic cylinder has the same length as the permanent magnet and is arranged outside the permanent magnet to provide necessary structural strength to support the lateral force.
3. The eddy current sensor according to claim 1, characterized in that: The metal probe is made of highly conductive non-magnetic metal. The working end of the metal probe is in the shape of a sharp knife and is built into the housing. During testing, the working end of the metal probe cuts the magnetic flux lines to generate an induced electromotive force, thereby generating an induced current.
4. An eddy current sensor according to claim 3, characterized in that: The fixed end of the metal probe is used to connect to the object to be measured, and the object to be measured can be an object of any material.
5. The eddy current sensor according to claim 1, characterized in that: The coil is arranged at the interface between the shell and the metal probe and is used to measure the magnitude of the induced current.