An electromagnetic ultrasonic sensor

Abstract

The utility model provides an electromagnetic ultrasonic sensor, comprising: a permanent magnet, an annular magnet and a coil; the permanent magnet and the annular magnet are on the same axis and bonded to the top of the annular magnet; the coil is bonded to the bottom of the annular magnet; the electromagnetic ultrasonic sensor is used to detect a workpiece to be detected, the workpiece to be detected is made of conductive and / or ferromagnetic material, and is placed under the coil and kept close to the coil. While ensuring the sensitivity of the electromagnetic ultrasonic sensor, the utility model optimizes the internal structure of the sensor to make the magnetic field more concentrated, reduce the size of the sensor, and make the sensor more efficient and have a longer service life.

Description

Technical Field

[0001] The utility model relates to the field of sensors, in particular to an electromagnetic ultrasonic sensor. Background Art

[0002] Electromagnetic ultrasonic technology (EMAT) uses electromagnetic coupling to excite and receive ultrasonic waves. It has been developed to a relatively mature stage and is widely used in many fields such as steel, electricity, petroleum, transportation, and medical treatment. The advantages of electromagnetic ultrasonic sensors are that they are non-contact and do not require coupling media.

[0003] However, the disadvantages of the currently known electromagnetic ultrasonic sensors are that the permanent magnet is large and the structure is not compact enough, resulting in a large volume of the entire sensor and an inability to quickly close the magnetic system, which leads to low operating efficiency of the sensor. For example, the electromagnetic ultrasonic sensor cannot be quickly removed from the surface of the workpiece, and dirt attracted to it by the magnetic field cannot be removed from the working surface of the electromagnetic ultrasonic sensor. Utility Model Content

[0004] The embodiment of the utility model provides an electromagnetic ultrasonic sensor to solve the problem of low working efficiency of the sensor due to the large size of the sensor and the inability to quickly close the magnetic system.

[0005] In order to solve the above problems, the utility model proposes an electromagnetic ultrasonic sensor, comprising:

[0006] A permanent magnet, an annular magnet and a coil; the permanent magnet and the annular magnet are on the same axis and bonded to the top of the annular magnet; the coil is bonded to the bottom of the annular magnet;

[0007] The electromagnetic ultrasonic sensor is used to detect a workpiece to be detected. The workpiece to be detected is made of conductive and / or ferromagnetic material and is placed under the coil and kept close to the coil.

[0008] Compared with the prior art, the beneficial effects of the utility model are:

[0009] The utility model places a permanent magnet and an annular magnet coaxially, adheres the permanent magnet to the top of the annular magnet, adheres the coil to the bottom of the annular magnet, and then places a workpiece to be detected made of conductive and / or ferromagnetic material under the coil and keeps it close to the coil, so that the overall structure is more compact and the magnetic field is more concentrated through the coil, so that the sensor has higher efficiency and longer service life. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] like Figure 1 Shown is a schematic diagram of the electromagnetic ultrasonic sensor of the first embodiment;

[0011] like Figure 2 FIG. 1 is a schematic diagram of magnetic lines of force of the first embodiment of the present invention.

[0012] Figure 1 In the figure, 1 is a permanent magnet, 2 is a ring magnet, 3 is a coil, 4 is a workpiece to be detected, 5 is a housing, 6 is a cover, and 7 is a cavity. DETAILED DESCRIPTION

[0013] The present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It is to be understood that the specific embodiments described herein are only used to explain the present invention, rather than to limit the present invention. It should also be noted that, for ease of description, only the parts related to the present invention, rather than all structures, are shown in the accompanying drawings.

[0014] It should be mentioned before discussing the exemplary embodiments in more detail that some exemplary embodiments are described as processes or methods depicted as flow charts. Although the flow charts describe the steps as sequential processes, many of the steps therein can be implemented in parallel, concurrently or simultaneously. In addition, the order of the steps can be rearranged. The process can be terminated when its operation is completed, but can also have additional steps not included in the accompanying drawings. The process can correspond to a method, function, procedure, subroutine, subprogram, etc.

[0015] In addition, the terms "first", "second", etc. may be used in this article to describe various directions, actions, steps or elements, but these directions, actions, steps or elements are not limited by these terms. These terms are only used to distinguish a first direction, action, step or element from another direction, action, step or element. For example, without departing from the scope of this application, the first feature information may be the second feature information or the third feature information, and similarly, the second feature information and the third feature information may be the first feature information. The first feature information and the second feature information and the third feature information are all feature information of a distributed file system, but they are not the same feature information. The terms "first", "second", etc. cannot be understood as indicating or implying relative importance or implicitly indicating the number of indicated technical features. Thus, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present utility model, the meaning of "multiple" and "batch" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0016] Embodiment 1

[0017] Figure 1 This is a schematic diagram of the structure of an electromagnetic ultrasonic sensor in the first embodiment of the utility model. This embodiment is applicable to the situation where the electromagnetic ultrasonic sensor is quickly removed from the surface of the workpiece. Figure 1 As shown, the electromagnetic ultrasonic sensor specifically includes:

[0018] A permanent magnet 1, an annular magnet 2 and a coil 3; the permanent magnet 1 and the annular magnet 2 are on the same axis and bonded to the top of the annular magnet 2; the coil 3 is bonded to the bottom of the annular magnet 2; the electromagnetic ultrasonic sensor is used to detect a workpiece 4 to be detected, the workpiece 4 to be detected is made of conductive and / or ferromagnetic material, and is placed under the coil 3 and kept close to the coil 3.

[0019] Specifically, the combination of the permanent magnet 1 and the annular magnet 2 is used to provide an external magnetic field. The conventional electromagnetic ultrasonic sensor uses only a permanent magnet or an electromagnet, resulting in the same magnetic force on the bottom, and the electromagnetic ultrasonic sensor cannot be quickly removed from the surface of the workpiece. By bonding the permanent magnet 1 to the annular magnet 2, the magnetic field strength near the inner diameter of the ring will be significantly stronger than the magnetic field near the outer diameter, and the magnetic force near the inner diameter of the ring will also be significantly stronger than that near the outer diameter. There is a magnetic force difference, which reduces the resistance during the movement, and the operator can quickly remove the electromagnetic ultrasonic sensor from the surface of the workpiece. The coil 3 is bonded to the annular magnet 2 to make the electromagnetic ultrasonic sensor compact. The structure of the coil includes but is not limited to: a Lu-shaped coil, a snake-shaped coil, a loop-shaped coil, a spiral coil, a runway-shaped coil, etc. Coils of different structures combined with an external magnetic field will excite the workpiece to produce different ultrasonic waves. The electromagnetic ultrasonic sensor is used to detect the workpiece 4 to be detected. The workpiece 4 to be detected needs to be conductive and / or ferromagnetic material in order to respond to produce ultrasonic waves in an environment where the magnetic field changes.

[0020] The permanent magnet 1 is a solid cylinder, and its diameter is larger than the inner diameter of the annular magnet 2, but smaller than the outer diameter of the annular magnet 2. The diameter of the permanent magnet 1 is between the inner diameter and the outer diameter of the annular magnet 2. In this way, at the bottom of the electromagnetic ultrasonic sensor, the magnetic field from the inner diameter of the annular magnet 2 to the diameter of the permanent magnet 1 is actually stronger, while the magnetic field from the diameter of the permanent magnet 1 to the outer diameter of the annular magnet 2 is relatively weaker.

[0021] The magnetic field direction of the permanent magnet 1 is vertical.

[0022] Figure 2 The figure shows a schematic diagram of magnetic lines of force provided by the first embodiment. At this time, the magnetic field direction of the permanent magnet 1 is vertically downward, and under the influence of the annular magnet 2 , the magnetic field at the bottom is concentrated near the inner diameter of the annular magnet 2 .

[0023] In addition, the electromagnetic ultrasonic sensor also includes a shell 5 and a cover body 6: the annular magnet 2 is placed inside the shell 5 and its outer ring surface is in contact with the inner wall of the shell 5, the top of the cover body 6 is flush with the top of the shell 5 to form the top of the electromagnetic ultrasonic sensor, and the bottom of the shell 5 is flush with the bottom of the coil 3 to form the bottom of the electromagnetic ultrasonic sensor. By adjusting the size of the shell 5 and the cover body 6, and then selecting the permanent magnet 1 and the annular magnet 2 of appropriate size, the overall size of the electromagnetic ultrasonic sensor can be made smaller. The bottom of the cover body 6 is provided with a groove, and one end of the permanent magnet 1 is in contact with the groove at the bottom of the cover body 6, on the one hand to secure the permanent magnet 1, and on the other hand to save space.

[0024] In addition, the electromagnetic ultrasonic sensor also includes a cavity 7, which is formed by the space between the permanent magnet 1 and the annular magnet 2, and the material used to form the magnetic field concentrator is poured into the cavity 7. In this way, the magnetic field concentrator is placed in the magnetic flux loop around the coil 3, and is tightly embedded in the electromagnetic ultrasonic sensor, with its opening facing the workpiece 4 to be detected, focusing the magnetic lines of force rotating around the coil 3, and driving the energy to be concentrated on the surface of the workpiece 4 to be detected.

[0025] The high-frequency current is connected or disconnected in the coil 3. When the high-frequency current passes through the coil 3 placed on the surface of the workpiece 4 to be detected, it will generate eddy currents in the skin layer of the workpiece 4 to be detected. Under the action of the external magnetic field, the eddy currents will be subjected to mechanical force to generate high-frequency vibrations, forming an ultrasonic wave source. When receiving ultrasonic waves, the oscillation of the surface of the workpiece 4 to be detected will also induce voltage in the coil 3 under the action of the external magnetic field force and be received by the instrument.

[0026] An electromagnetic ultrasonic sensor provided in this embodiment is achieved by placing a permanent magnet and an annular magnet coaxially, gluing the permanent magnet directly below the annular magnet, gluing the coil directly below the annular magnet, and then placing a workpiece to be detected made of conductive and / or ferromagnetic material under the coil and keeping it close to the coil, then placing the annular magnet inside the housing and fitting it to the housing, and the permanent magnet is fitted into the groove at the bottom of the cover, and the cavity is filled with a magnetic field concentrator, so that the overall structure is more compact, and the magnetic field can be more concentrated to pass through the coil, so that the sensor is more efficient and has a longer service life, and the resistance to the operator is reduced, so the electromagnetic ultrasonic sensor can be quickly removed from the surface of the workpiece, and the magnetic system can also be quickly closed.

[0027] Note that the above are only preferred embodiments of the present invention and the technical principles used. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and that various obvious changes, readjustments and substitutions can be made by those skilled in the art without departing from the scope of protection of the present invention. Therefore, although the present invention is described in more detail through the above embodiments, the present invention is not limited to the above embodiments, and may include more other equivalent embodiments without departing from the concept of the present invention, and the scope of the present invention is determined by the scope of the appended claims.

Claims

1. An electromagnetic ultrasonic sensor, characterized in that: include: A permanent magnet, an annular magnet and a coil; the permanent magnet and the annular magnet are on the same axis and bonded to the top of the annular magnet; The coil is bonded directly below the annular magnet; The electromagnetic ultrasonic sensor is used to detect a workpiece to be detected. The workpiece to be detected is made of conductive and / or ferromagnetic material and is placed under the coil and kept close to the coil.

2. The electromagnetic ultrasonic sensor according to claim 1, characterized in that: The permanent magnet is a solid cylinder, the diameter of which is larger than the inner diameter of the annular magnet and smaller than the outer diameter of the annular magnet.

3. The electromagnetic ultrasonic sensor according to claim 2, characterized in that: The magnetic field direction of the permanent magnet is vertical.

4. The electromagnetic ultrasonic sensor according to claim 1, characterized in that: It also includes a shell and a cover body: the annular magnet is placed inside the shell and its outer ring surface is in contact with the inner wall of the shell, the top of the cover body is flush with the top of the shell to form the top of the electromagnetic ultrasonic sensor, and the bottom of the shell is flush with the bottom of the coil to form the bottom of the electromagnetic ultrasonic sensor.

5. The electromagnetic ultrasonic sensor according to claim 4, characterized in that: The bottom of the cover body is provided with a groove, and one end of the permanent magnet is fitted and embedded in the groove at the bottom of the cover body.

6. The electromagnetic ultrasonic sensor according to claim 1, characterized in that: Also included is a cavity in which a material for forming a magnetic field concentrator is poured.

7. The electromagnetic ultrasonic sensor according to claim 6, characterized in that: The cavity is formed by the space between the permanent magnet and the annular magnet.

8. The electromagnetic ultrasonic sensor according to claim 1, characterized in that: The coil is used to pass or disconnect high-frequency current.

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