Magnetic measurement probe for positioning residual stress by using rotary encoder and detection equipment

Abstract

The utility model discloses a magnetic measurement probe and detection equipment for positioning residual stress by using a rotary encoder, the magnetic measurement probe comprises an excitation magnetic pole, an induction magnetic pole and the rotary encoder, the rotary encoder is fixedly connected with the excitation magnetic pole, and the excitation magnetic pole is rotatably connected with the induction magnetic pole. According to the magnetic measurement probe for positioning the residual stress by using the rotary encoder and the detection equipment, the detection precision of the residual stress is improved.

Description

Technical Field

[0001] The present application relates to the technical field of detection, and in particular, to a magnetic measurement probe and a detection device for positioning residual stress by using a rotary encoder. Background Art

[0002] At present, the technology for measuring welding residual stress based on the inverse magnetostrictive effect has been relatively mature, and the types of probes used for measurement have developed from the initial two-pole and three-pole to nine-pole. The basic measurement principles of these probes are the same, and the stress is measured by using the magnetic anisotropy of the material. During measurement, a closed magnetic circuit is formed between the sensor and the material surface. When there is residual stress in the measured component, the magnetic permeability of the material changes from the original magnetic isotropy to magnetic anisotropy, and the magnetic resistance and magnetic flux of the closed circuit change. The sensor can sense this change and output it as a macroscopically visible voltage signal to reflect the change and distribution of the stress.

[0003] At present, in order to improve the detection accuracy, the number of probe poles is increased to improve the accuracy of the main stress direction positioning. Due to the limitations of the probe size, material, magnetic field interference, and measurement operation, there is a problem of large measurement error. Conventional sensors are two-pole, four-pole, and nine-pole sensors. As the number of probes used for measurement increases, the detection angles are also finely divided. However, for the nine-pole magnetic measurement probe, except for the middle excitation magnetic pole, the remaining eight induction magnetic poles are distributed around the excitation magnetic pole. It is equivalent that each induction magnetic pole takes into account the magnetic field within a range of 45 degrees, and still cannot further accurately determine the main stress direction of the residual stress in the angular direction. Summary of the Utility Model

[0004] In view of this, the present application provides a magnetic measurement probe, a detection device, and a detection method for positioning residual stress by using a rotary encoder, which improve the detection accuracy of residual stress.

[0005] In a first aspect, the present application provides a magnetic measurement probe for positioning residual stress by using a rotary encoder, which includes an excitation magnetic pole, an induction magnetic pole, and a rotary encoder. The rotary encoder is fixedly connected to the excitation magnetic pole, and the excitation magnetic pole is rotatably connected to the induction magnetic pole.

[0006] By adopting the above technical solution, when the excitation magnetic pole is energized, it will form a stable and controllable magnetic field in the surrounding space. This magnetic field will interact with the residual stress in the material to be measured, resulting in changes in the magnetic field distribution. The induction magnetic pole detects the subtle changes generated by the interaction between the magnetic field generated by the excitation magnetic pole and the residual stress in the material. These changes usually manifest as changes in the magnetic field intensity or offsets in the magnetic field direction, which can be captured by sensors (such as Hall sensors or magnetoresistive sensors) in the induction magnetic pole. The rotary encoder is fixedly connected to the excitation magnetic pole, and its function is to provide accurate angle or position information. Since the excitation magnetic pole and the induction magnetic pole are rotatably connected, the rotary encoder can record the relative rotation angle or position change between the two in real time. This position information is crucial for analyzing the magnetic field changes caused by residual stress because it helps establish the spatial correspondence between the magnetic field changes and the residual stress distribution.

[0007] By adding a rotary encoder, the positions of multiple outer-ring induction magnetic poles are located, and the outer-ring induction magnetic poles are rotated at a small fixed angle to increase the measurement density, obtain residual stress measurement values at multiple angles, and improve the measurement accuracy of the principal stress direction.

[0008] In some embodiments, the induction magnetic pole is provided with a receiving space, and the rotary encoder is located in the receiving space and rotatably connected to the induction magnetic pole.

[0009] By adopting the above technical solution, placing the rotary encoder in the receiving space of the induction magnetic pole can effectively protect it from the influence of the external environment, such as dust, moisture, or mechanical shock, thereby extending its service life. The rotary encoder and the induction magnetic pole are closely integrated, and their relative position relationship is more stable, which helps to reduce measurement errors caused by mechanical looseness or vibration and improve the measurement accuracy and reliability. This design simplifies the structure of the entire probe, making the connection between each component more compact and efficient.

[0010] In some embodiments, a fixing cover is further included. The fixing cover is connected to the induction magnetic pole to enclose the receiving space, and the excitation magnetic pole is rotatably connected to the fixing cover.

[0011] By adopting the above technical solution, the connection between the fixing cover and the induction magnetic pole effectively encloses the receiving space, prevents external impurities from entering, enhances the sealing performance and dust and water resistance of the probe, and can also ensure the relative position stability between the two during the measurement process, reducing measurement errors caused by connection looseness.

[0012] In some embodiments, the rotary encoder is a travel encoder, and the rotary encoder can drive the induction magnetic pole to rotate at a certain angle.

[0013] In some embodiments, each time the rotary encoder actuates, the induction magnetic pole rotates by 5°.

[0014] By adopting the above technical solution, the rotary encoder is not only used to measure the rotation angle of the induction magnetic pole, but also directly controls the rotation of the induction magnetic pole. By controlling the rotation of the induction magnetic pole, the probe can scan the magnetic field changes inside the material at multiple angles during the rotation process, so as to obtain more comprehensive distribution information of the residual stress. It can not only cover the entire measurement range faster, improve the measurement efficiency, but also reduce the measurement error caused by mechanical vibration or unstable factors.

[0015] In some embodiments, the induction magnetic poles are uniformly distributed around the excitation magnetic pole in the circumferential direction with the excitation magnetic pole as the center.

[0016] In some embodiments, the ends of the induction magnetic poles and the ends of the excitation magnetic poles are located in the same plane.

[0017] By adopting the above technical solution, it is possible to more comprehensively capture the subtle changes generated after the interaction between the magnetic field generated by the excitation magnetic pole and the residual stress of the material, which helps to improve the sensitivity and accuracy of the measurement. Due to the symmetry of the layout of the induction magnetic poles, the data processing process can be simplified, making it easier to extract useful information from the measurement data. When the ends of the induction magnetic poles and the excitation magnetic poles are located in the same plane, the magnetic field coupling between them is closer, which helps to reduce the loss and interference of the magnetic field during propagation and improve the stability of the measurement.

[0018] In some embodiments, the induction magnetic poles are connected with induction coils, and the excitation magnetic poles are connected with excitation coils.

[0019] In some embodiments, the induction magnetic poles are two-pole, four-pole or eight-pole probes, and each induction magnetic pole is connected with an induction coil. The wiring method of the induction coils is that the induction coils corresponding to the diagonally distributed induction magnetic poles are connected in series in the forward direction, and the adjacent two groups of induction coils are connected in reverse differential.

[0020] By adopting the above technical solution, at the diagonal positions of the probe, the induction coils corresponding to the two induction magnetic poles are connected in series in the forward direction, which helps to enhance the signal intensity, because the induction magnetic poles at the diagonal positions are usually in the area where the magnetic field changes most significantly. The adjacent two groups of induction coils are connected in reverse differential, which can effectively suppress the common-mode noise and interference signals and improve the signal-to-noise ratio of the measurement. In this case, the reverse differential connection can further reduce the measurement error caused by external factors (such as temperature change, electromagnetic interference, etc.).

[0021] In a second aspect, the present application provides a detection device, including the magnetic measurement probe for positioning residual stress using a rotary encoder in the first aspect.

[0022] By adopting the above technical solution, the detection device can achieve high-precision measurement of the internal residual stress of materials, can realize automatic operation, and has the advantages of non-contact and non-destructive.

[0023] In summary, the present application has at least one of the following beneficial technical effects:

[0024] 1. The probe of the present application has a simple structure, a compact connection, and high measurement accuracy.

[0025] 2. The probe of the present application is safer and more stable in measurement, reduces measurement errors, and improves measurement efficiency.

[0026] 3. The detection device of the present application can achieve high-precision measurement of the internal residual stress of materials, can realize automatic operation, and has the advantages of non-contact and non-destructive. Description of the Drawings

[0027] Figure 1 is a schematic diagram of the external structure of the first embodiment of the magnetic measurement probe for positioning residual stress using a rotary encoder in the present application;

[0028] Figure 2 is a schematic diagram of the internal structure of the first embodiment of the magnetic measurement probe for positioning residual stress using a rotary encoder in the present application;

[0029] Figure 3 is a schematic diagram of the disassembled structure of the first embodiment of the magnetic measurement probe for positioning residual stress using a rotary encoder in the present application;

[0030] Figure 4 is a schematic diagram of the structure of the second embodiment of the magnetic measurement probe for positioning residual stress using a rotary encoder in the present application.

[0031] Description of the Reference Numerals:

[0032] 1. Excitation magnetic pole; 11. Excitation coil; 2. Induction magnetic pole; 21. First induction magnetic pole; 22. Second induction magnetic pole; 23. Third induction magnetic pole; 24. Fourth induction magnetic pole; 3. Induction coil; 31. First induction coil; 32. Second induction coil; 33. Third induction coil; 34. Fourth induction coil; 4. Substrate; 41. Accommodating space; 42. Through hole; 5. Fixed cover; 6. Rotary encoder. Detailed Embodiments

[0033] To make the objectives, technical solutions, and advantages of the embodiments of the present utility model clearer, the present utility model will be further described in detail below with reference to the accompanying drawings. The components of the embodiments of the present utility model described and illustrated in the drawings here can be arranged and designed in various different configurations. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present utility model without creative efforts shall fall within the scope of protection of the present utility model.

[0034] It should be noted that like reference numerals and letters denote like items in the following drawings. Therefore, once an item is defined in one drawing, it does not need to be further defined and explained in subsequent drawings.

[0035] In the description of the present utility model, it should be noted that unless otherwise clearly defined and limited, the terms "installation", "connection", and "connection" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present utility model can be understood according to specific situations.

[0036] In the description of the present application, it should be understood that the orientation or positional relationship indicated by the terms "upper", "lower", "left", "right", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present application.

[0037] The embodiments of the present utility model will be described in detail below with reference to the accompanying drawings. Without conflict, the features in the following embodiments can be combined with each other.

[0038] Embodiment 1

[0039] Please refer to Figures 1-3 , which discloses a magnetic measurement probe for positioning residual stress using a rotary encoder 6, including an excitation magnetic pole 1, an induction magnetic pole 2, and a rotary encoder 6. The rotary encoder 6 is fixedly connected to the excitation magnetic pole 1, and the excitation magnetic pole 1 is rotatably connected to the induction magnetic pole 2.

[0040] Please refer to Figure 1, in this embodiment, a five-pole probe is adopted, that is, 4 induction magnetic poles 2 and 1 excitation magnetic pole 1. The induction magnetic poles 2 are evenly distributed around the excitation magnetic pole 1 in the circumferential direction with the excitation magnetic pole 1 as the center. The induction magnetic pole 2 includes a base body 4. The induction magnetic pole 2 is fixedly and insulatedly connected to the base body 4. The excitation magnetic pole 1 is rotatably connected to the base body 4. The end of the induction magnetic pole 2 far from the base body 4 and the end of the excitation magnetic pole 1 far from the base body 4 are located in the same plane. An excitation coil 11 is sleeved on the excitation magnetic pole 1. The four induction magnetic poles 2 are respectively a first induction magnetic pole 21, a second induction magnetic pole 22, a third induction magnetic pole 23 and a fourth induction magnetic pole 24. A first induction coil 31 is sleeved on the first induction magnetic pole 21, a second induction coil 32 is sleeved on the second induction magnetic pole 22, a third induction coil 33 is sleeved on the third induction magnetic pole 23, and a fourth induction coil 34 is sleeved on the fourth induction magnetic pole 24. One end of the first induction coil 31 and one end of the third induction coil 33 are connected in series in the forward direction. One end of the second induction coil 32 and one end of the fourth induction coil 34 are connected in series in the forward direction. The other end of the first induction coil 31 and the other end of the second induction coil 32 are connected in differential connection in the reverse direction. The other end of the third induction coil 33 and the other end of the fourth induction coil 34 are connected in differential connection in the reverse direction. A fixing cover 5 is connected to one end of the base body 4 far from the induction magnetic pole 2. The fixing cover 5 is threadedly connected to the base body 4.

[0041] Please refer to Figure 2 , the magnetic measurement probe of the present application further includes a rotary encoder 6. The rotary encoder 6 is fixedly connected to the excitation magnetic pole 1. The base body 4 is provided with a receiving space 41. The receiving space 41 is adapted to the rotary encoder 6. The rotary encoder 6 is rotatably arranged in the receiving space 41. The fixing cover 5 is threadedly connected to the base body 4 to enclose the rotary encoder 6 in the receiving space 41.

[0042] Please refer to Figure 2 and Figure 3 , the base body 4 further includes a through hole 42 communicating with the receiving space 41. The excitation magnetic pole 1 passes through the through hole 42 and is rotatably connected to the base body 4. The excitation magnetic pole 1 is rotatably connected to the fixing cover 5. After passing through the through hole 42 of the base body 4, the excitation magnetic pole 1 is connected to the excitation coil 11. The rotary encoder 6 is a travel encoder. Each time the rotary encoder 6 acts, it can drive the induction magnetic pole 2 to rotate at an angle of 2° to 10°. In this embodiment, each time the rotary encoder 6 acts, the induction magnetic pole 2 rotates 5°.

[0043] When there is no residual stress in the test component, the induction magnetic pole 2 is at the isomagnetic point, and the output voltage of the induction coil 3 is zero. When there is residual stress in the test component, under the magnetization of the excitation magnetic pole 1, the magnetic permeability in the stress direction and the direction perpendicular to the stress direction will be inconsistent, that is, magnetic anisotropy is generated, and at this time the output voltage is not zero.

[0044] Let the initial measurement output voltage be V1. At this time, the output voltage can be expressed by the following formula:

[0045] V1 = K(σ1 - σ2)cos2θ (1)

[0046] Let the output voltage after rotating 5° be V2, then the output voltage at this time is:

[0047]

[0048] Where: K is the sensitivity coefficient, which needs to be calibrated through experiments; θ is the angle between the stress and the probe direction.

[0049] By operating formulas (1) and (2), the principal stress difference (σ1 - σ2) and the principal stress direction angle θ of the residual stress can be obtained, so as to achieve the purpose of measuring the direction positioning and magnitude of the residual stress at various angles.

[0050] The rotary encoder 6 is located between the induction magnetic pole 2 and the fixed cover 5 and can drive the induction magnetic pole 2 to rotate.

[0051] The beneficial effect of the present invention is that the device solves the problem of needing to rotate the probe for measurement, and can improve the test efficiency and detection accuracy.

[0052] The detection steps are as follows:

[0053] 1. Analyze the material of the detection part before detection. Different materials should use different calibration coefficients K.

[0054] 2. Determine the detection depth before detection. Different detection depths should use different excitation parameters.

[0055] 3. Contact the excitation magnetic pole 1 probe and the induction magnetic pole 2 probe with the structure workpiece to be detected, ensure that the probe is in full contact with the detection surface, and temporarily adjust the probe measurement direction and fix it firmly.

[0056] 4. Adjust the host to the working state.

[0057] 5. Ensure that the probe sensor is in contact with the test part and is basically the same as the calibration specimen. If the requirements cannot be met, the non-direct contact measurement can be carried out by using the method of sticking a thin film.

[0058] 6. Zero the host.

[0059] 7. After the detection is completed at the initial position, keep the overall position of the magnetic measurement device unchanged, and set the rotary encoder 6 to drive the induction magnetic pole 2 to change positions for detection with a rotation angle of 5°.

[0060] 8. Repeat the operation in step 7 until the rotary encoder 6 rotates a total of 90°.

[0061] 9. Compare the detection result of the last time (i.e., when the encoder rotates 90°) with the detection result of the initial position, and analyze the error; if the detection result error is relatively large, re-detect.

[0062] Example 2

[0063] Please refer to Figure 4 , the difference between this embodiment and Embodiment 1 is that there are 8 induction magnetic poles 2, and the 8 induction magnetic poles 2 are evenly distributed along the circumferential direction of the excitation magnetic pole 1. The induction magnetic pole 2 can also be designed as a two-pole probe according to needs.

[0064] Example 3

[0065] This embodiment discloses a detection device, including the magnetic measurement probe for positioning residual stress using the rotary encoder 6 in Embodiment 1 or Embodiment 2.

[0066] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited by the above embodiments, and what is described in the above embodiments and the specification only illustrates the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention will have various changes, modifications, substitutions and variations, and these changes, modifications, substitutions and variations all fall within the scope of the present invention claimed.

Claims

1. A magnetic probe for locating residual stress using a rotary encoder (6), characterized in that: It comprises an excitation magnetic pole (1), an induction magnetic pole (2) and a rotary encoder (6), wherein the rotary encoder (6) is fixedly connected to the excitation magnetic pole (1), and the excitation magnetic pole (1) is rotatably connected to the induction magnetic pole (2).

2. The magnetic probe for locating residual stress using a rotary encoder (6) according to claim 1, characterized in that: The induction magnetic pole (2) is provided with a receiving space (41), and the rotary encoder (6) is located in the receiving space (41) and is rotationally connected to the induction magnetic pole (2).

3. The magnetic probe for locating residual stress using a rotary encoder (6) according to claim 2, characterized in that: It also comprises a fixed cover (5), the fixed cover (5) being connected to the induction magnetic pole (2) to close the accommodation space (41), and the excitation magnetic pole (1) being rotatably connected to the fixed cover (5).

4. The magnetic measuring probe for locating residual stress using a rotary encoder (6) according to claim 1, characterized in that: The rotary encoder (6) is a travel encoder, and the rotary encoder (6) can drive the induction magnetic pole (2) to rotate.

5. The magnetic probe for locating residual stress using a rotary encoder (6) according to claim 4, characterized in that: Each time the rotary encoder (6) moves once, the induction magnetic pole (2) rotates 5°.

6. The magnetic probe for locating residual stress using a rotary encoder (6) according to claim 1, characterized in that: The induction magnetic poles (2) are evenly distributed around the excitation magnetic pole (1) in a circumferential direction with the excitation magnetic pole (1) as the center.

7. The magnetic probe for locating residual stress using a rotary encoder (6) according to claim 6, characterized in that: The end of the induction magnetic pole (2) and the end of the excitation magnetic pole (1) are located in the same plane.

8. The magnetic probe for locating residual stress using a rotary encoder (6) according to claim 6, characterized in that: The induction magnetic pole (2) is connected to an induction coil (3), and the excitation magnetic pole (1) is connected to an excitation coil (11).

9. The magnetic measuring probe for locating residual stress using a rotary encoder (6) according to claim 8, characterized in that: The induction magnetic poles (2) are dipole, quadrupole or octupole probes, each of the induction magnetic poles (2) is connected to an induction coil (3), and the induction coils (3) are connected in the following manner: the induction coils (3) corresponding to the diagonally distributed induction magnetic poles (2) are connected in series in the forward direction, and two adjacent groups of induction coils (3) are connected in the reverse direction in a differential manner.

10. A detection device, characterized in that: It comprises a magnetic measuring probe for locating residual stress using a rotary encoder (6) as described in any one of claims 1 to 9.

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