A device for detecting inner hole defects of non-uniform hollow shafts

Abstract

The present application discloses a device for detecting defects in the inner hole of a non-uniform hollow shaft, comprising a robotic arm, an electromagnetic array eddy current sensor, a linear Hall sensor, and an intelligent eddy current detector. The linear Hall sensor determines the distance between the electromagnetic array eddy current sensor and the inner wall of the hollow shaft by acquiring the magnetic induction change of the induction coil, and then adjusts the position of the electromagnetic array eddy current sensor according to the robotic arm, so as to achieve the purpose of making the electromagnetic array eddy current sensor close to the inner wall of the hollow shaft and improving the detection sensitivity; at the same time, the linear Hall sensor adopts an elastic part structure to ensure that the electromagnetic array eddy current sensor can maintain a close fit with the inside of the hollow shaft. Since the present application scans the hollow shaft with a non-uniform inner hole structure, compared with the traditional single-point eddy current probe, it has high detection efficiency and detection accuracy, and is more flexible to operate.

Description

Technical Field

[0001] The present application relates to the technical field of hollow shaft inner hole detection, and specifically to a device for detecting defects in the inner hole of a non-uniform-diameter hollow shaft. Background Art

[0002] Hollow shafts are highly corrosion-resistant and suitable for use in water, chemicals, and other oxidizing environments. Their lightweight design reduces overall weight while ensuring strength. They are widely used in aircraft engines, automotive transmission systems, wind turbines, and industrial equipment.

[0003] Among traditional nondestructive testing methods, ultrasonic testing is the primary method currently used. If small surface defects exist on the inner wall of a hollow shaft, ultrasonic testing can easily lead to blind spots and missed detections. Eddy current testing, one of the five conventional nondestructive testing methods, is based on the principle of electromagnetic induction. It requires no coupling agent and offers high sensitivity, enabling detection of minute surface defects on test pieces with instant data feedback, making it suitable for on-site, real-time testing of hollow shafts.

[0004] CN202122818101.8 discloses a hollow shaft inner hole array eddy current flaw detection device, including a skeleton, a connecting rod, a connecting sleeve, a telescopic part, an array coil and an array channel, wherein: a first hollow cavity is opened in the connecting rod; a hollow cavity is provided in the connecting sleeve, one end of the connecting sleeve is sleeved and installed on the outer wall of the connecting rod, and the other end of the connecting sleeve is used to be installed on a control platform; the array coil includes a first terminal; a second hollow cavity is opened in the skeleton, a groove is opened on the outer wall of the skeleton, and the array coil is wound on the groove; the telescopic part includes a first fixed end and a second fixed end, the first fixed end is installed on the skeleton and can be telescopically moved along the length direction of the connecting rod, and the second fixed end is installed on the control platform; the array channel includes a second terminal and a third terminal, and the second terminal is connected to the first terminal.

[0005] The inspection method involves connecting an array eddy current detector to a scanning and pushing mechanism connected to a PC. The scanning and pushing mechanism drives a probe via a chain, automatically extending it along a guide sleeve into the inner bore of a hollow shaft. A motor drives the probe smoothly forward and backward through the inner bore. The probe covers the entire inner wall of the hollow shaft, collecting surface defect signals as it exits the shaft. The array eddy current detector collects and processes the defect signals transmitted by the probe, ultimately obtaining surface defect information and transmitting it to the PC, completing the inspection of the hollow shaft's inner bore.

[0006] However, the probe used in the above-mentioned hollow shaft inner hole array eddy current flaw detection device is a single-point eddy current probe. The single-point eddy current probe has inherent technical limitations when dealing with variable curvature tubular cavity structures. Since the hollow shaft adopts a non-equal diameter inner hole design, the traditional single-point eddy current probe cannot ensure a close fit with the inner wall of the hollow shaft, thereby affecting the detection sensitivity and detection accuracy. Summary of the Invention

[0007] The purpose of this application is to provide a device for detecting defects in the inner hole of a non-uniform hollow shaft, so as to solve the problem proposed in the above background technology that the traditional single-point eddy current probe cannot ensure close fit to the inner wall of the hollow shaft, thereby affecting the detection sensitivity and detection accuracy.

[0008] To achieve the above objectives, this application provides the following technical solutions:

[0009] A device for detecting defects in the inner hole of a non-uniform hollow shaft includes a robotic arm, an electromagnetic array eddy current sensor, a linear Hall sensor, and an intelligent eddy current detector. The robotic arm is responsible for receiving control instructions and adjusting the detection posture of the electromagnetic array eddy current sensor according to the control instructions. The linear Hall sensor is detachably mounted on the robotic arm and is used to detect the contact state between the electromagnetic array eddy current sensor and the inner wall of the hollow shaft. The electromagnetic array eddy current sensor is axially movable on the linear Hall sensor via a mounting assembly. The intelligent eddy current detector is disposed on one side of the robotic arm and is used to obtain detection data from the electromagnetic array eddy current sensor and transmit the detection data to a host computer for imaging of the detection results.

[0010] An elastic member is sleeved on the mounting assembly, and two ends of the elastic member are respectively in contact with the mounting assembly and the linear Hall sensor.

[0011] In one embodiment, the electromagnetic array eddy current sensor includes an S-shaped array coil assembly, the S-shaped array coil assembly includes a four-element detection array and a three-element detection array, and the four-element detection array and the three-element detection array form a spatial phase difference distribution structure.

[0012] In one embodiment, the robotic arm is a six-degree-of-freedom robotic arm, which includes six rotational joints.

[0013] In one embodiment, the mounting assembly includes a mounting base and at least two support columns. The mounting base is fixedly or detachably mounted on the electromagnetic array eddy current sensor. One end of the support column is passed through the mounting base, and the other end is mounted on the linear Hall sensor. The mounting base can slide along the support column. The elastic member is sleeved on the support column and its two ends are respectively abutted against the mounting base and the linear Hall sensor.

[0014] In one embodiment, the mounting seat and the two support columns are interference-connected.

[0015] In one embodiment, the elastic member is a spring.

[0016] In one embodiment, the linear Hall sensor is mounted on the robotic arm through a mounting tube, and the mounting tube is a hollow structure.

[0017] In one embodiment, one end of the mounting tube has a mounting hole, and there are two mounting holes symmetrically arranged on the outer wall of one end of the mounting tube.

[0018] In one embodiment, the linear Hall sensor has a mounting portion, a receiving hole is provided on the mounting portion, a mounting tube is inserted into the receiving hole, a fixing hole is provided on the mounting portion, when the mounting tube is inserted into the receiving hole, the fixing hole and the mounting hole are aligned with each other and connected, and the external connector is inserted into the fixing hole and the mounting hole in sequence.

[0019] In one embodiment, the end of the robotic arm close to the mounting tube has a fixed sleeve, the fixed sleeve is detachably mounted on the robotic arm, and the mounting tube is plugged into the fixed sleeve.

[0020] Compared with the prior art, the present invention has the following advantages:

[0021] In the process of detecting internal defects of a hollow shaft with a traditional single-point eddy current probe, due to the non-uniform inner hole design of the hollow shaft, the single-point eddy current probe cannot fit tightly against the inside of the hollow shaft during the detection process; therefore, the present application provides a non-uniform inner hole defect detection device for a hollow shaft, including a robotic arm, an electromagnetic array eddy current sensor, a linear Hall sensor, and an intelligent eddy current detector. The linear Hall sensor obtains the magnetic induction changes of the induction coil to judge the distance between the electromagnetic array eddy current sensor and the inner wall of the hollow shaft, and then adjusts the position of the electromagnetic array eddy current sensor according to the robotic arm, so as to achieve the purpose of making the electromagnetic array eddy current sensor close to the inner wall of the hollow shaft and improving the detection sensitivity; at the same time, the present application adopts an elastic part structure on the linear Hall sensor to ensure that the electromagnetic array eddy current sensor can maintain a tight fit against the inside of the hollow shaft. Since the present application scans the hollow shaft with a non-uniform inner hole structure, compared with the traditional single-point eddy current probe, it has high detection efficiency and detection accuracy, and is more flexible and simple to operate. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is a schematic structural diagram of a non-uniform diameter hollow shaft inner hole defect detection device in this application;

[0023] Figure 2 This is a schematic diagram of the assembly structure of an electromagnetic array eddy current sensor, a linear Hall sensor, and a mounting tube for a non-uniform hollow shaft inner hole defect detection device in this application;

[0024] Figure 3 This is a schematic diagram of the assembly structure of an electromagnetic array eddy current sensor and a linear Hall sensor for a non-uniform hollow shaft inner hole defect detection device in this application;

[0025] Figure 4 This is a schematic structural diagram of an S-shaped array coil assembly of a non-uniform diameter hollow shaft inner hole defect detection device in this application.

[0026] Figure numerals: robotic arm 1, electromagnetic array eddy current sensor 2, S-shaped array coil assembly 21, four-element detection array 211, three-element detection array 212, linear Hall sensor 3, mounting portion 31, accommodating hole 311, fixing hole 312, intelligent eddy current detector 4, mounting assembly 5, mounting seat 51, two support columns 52, elastic member 6, mounting tube 7, mounting hole 71, fixed sleeve 8. DETAILED DESCRIPTION

[0027] To make the above-mentioned objects, features, and advantages of the present application more clearly understood, the specific embodiments of the present application are described in detail below with reference to the accompanying drawings. The following description sets forth many specific details to facilitate a full understanding of the present application. However, the present application can be implemented in many other ways than those described herein, and those skilled in the art can make similar improvements without violating the scope of the present application. Therefore, the present application is not limited to the specific embodiments disclosed below.

[0028] It should be noted that when an element is considered to be "connected" to another element, it can be directly connected to the other element or there may be an intermediate element. In contrast, when an element is said to be "directly" connected to another element, there are no intermediate elements.

[0029] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this application pertains. The terms used herein in the specification of this application are intended only to describe specific embodiments and are not intended to limit this application. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0030] like Figure 1 and Figure 2 As shown: A non-uniform diameter hollow shaft inner hole defect detection device includes a robotic arm 1, an electromagnetic array eddy current sensor 2, a linear Hall sensor 3, and an intelligent eddy current detector 4. The robotic arm 1 is responsible for receiving control instructions and adjusting the detection posture of the electromagnetic array eddy current sensor 2 according to the control instructions. The linear Hall sensor 3 is detachably mounted on the robotic arm 1 and is used to detect the fit between the electromagnetic array eddy current sensor 2 and the inner wall of the hollow shaft. The electromagnetic array eddy current sensor 2 is axially movably mounted on the linear Hall sensor 3 through a mounting assembly 5. The intelligent eddy current detector 4 is arranged on one side of the robotic arm 1 and is used to obtain detection data from the electromagnetic array eddy current sensor 2 and transmit the detection data to a host computer for imaging of the detection results.

[0031] An elastic member 6 is sleeved on the mounting assembly 5 , and two ends of the elastic member 6 are respectively in contact with the mounting assembly 5 and the linear Hall sensor 3 .

[0032] The elastic member 6 is a spring, and the robotic arm 1 is a six-degree-of-freedom robotic arm, which includes six rotational joints.

[0033] Linear Hall sensors 3 are distributed above the electromagnetic array eddy current sensor 2, forming an integrated detection device. The host computer connects the electromagnetic array eddy current sensor 2 and the robotic arm 1. The servo motor controls the relative movement between the non-uniform hollow shaft and the integrated detection device, thus achieving eddy current detection.

[0034] The primary magnetic field excited by the electromagnetic array eddy current sensor 2 induces eddy currents on the inner wall surface of the hollow shaft. The magnetic field generated by the induced eddy currents reacts on the magnetic field of the S-type array coil assembly 21, causing the impedance of the S-type array coil assembly 21 to change, thereby causing the voltage in the S-type array coil assembly 21 to change. The intelligent eddy current detector 4 analyzes and processes the received changed voltage signal to obtain defect information.

[0035] The linear Hall sensor 3 collects changes in the primary magnetic field in real time, thus determining the size of the induced eddy currents. As the fit between the electromagnetic array eddy current sensor 2 and the inner wall of the hollow shaft varies, the induced eddy currents differ, and their impact on the primary magnetic field also varies. Therefore, changes in the primary magnetic field are correlated to the fit between the electromagnetic array eddy current sensor 2 and the inner wall of the hollow shaft. The linear Hall sensor 3 detects changes in the primary magnetic field and outputs an analog voltage signal related to the distance. The output signal is processed through filtering, noise reduction, signal amplification and standardization, and analog-to-digital conversion (ADC). The output signal is then transmitted to the host computer, which analyzes the output signal to obtain the actual distance d between the linear Hall sensor 3 and the inner wall of the hollow shaft. 实际 , and the target distance d between the linear Hall sensor 3 and the inner wall of the hollow shaft when the detection device is tightly fitted to the hollow shaft 目标 , calculation error e(t)=d 目标 -d 实际 , the control variable u(t) is generated by the PID algorithm, the direction and amplitude of the robot arm 1 to move are determined, the smooth trajectory is planned by the inverse kinematics of the robot arm 1, and then the motor is used to drive the robot arm joint to move to the target angle. The encoder provides real-time feedback on the actual angle, and the actual angle is compared with the target angle for fine-tuning. Repeat the above steps until |d 目标 -d 实际 |<Specified error, thereby ensuring the fit between the electromagnetic array eddy current sensor 2 and the inner wall of the hollow shaft.

[0036] A dedicated clamping mechanism stabilizes the hollow shaft and drives it to rotate at a constant speed around its central axis. A robotic arm 1 precisely delivers the integrated electromagnetic array eddy current sensor 2 and linear Hall sensor 3 to a designated inspection point within the hollow shaft. The electromagnetic array eddy current sensor 2 detects the defect signal at the designated point and transmits it to the intelligent eddy current detector 4. After the hollow shaft completes a full rotation, the robotic arm 1 drives the integrated electromagnetic array eddy current sensor 2 and linear Hall sensor 3 forward along the axis. The built-in linear Hall sensor 3 continuously monitors the distance between the electromagnetic array eddy current sensor 2 and the hollow shaft wall, ensuring that the electromagnetic array eddy current sensor 2 maintains stable contact with the hollow shaft wall within the variable-diameter hollow shaft pipeline.

[0037] The intelligent eddy current detector 4 is responsible for collecting the defect signals transmitted by the electromagnetic array eddy current sensor 2 and performing signal processing, and finally obtaining the information of the surface defects of the inner hole of the hollow shaft and transmitting it to the PC, thereby completing the detection of the surface defects of the inner hole of the hollow shaft.

[0038] Repeat the above process to obtain the inspection data of different areas of the inner wall of the hollow shaft in turn, and complete the defect inspection of the inner wall of the hollow shaft.

[0039] In this way, a device for detecting defects in the inner hole of a non-equal diameter hollow shaft is provided by the coordinated arrangement of a robotic arm 1, an electromagnetic array eddy current sensor 2, a linear Hall sensor 3, and an intelligent eddy current detector 4. In the process of detecting internal defects of a hollow shaft by a traditional single-point eddy current probe, due to the non-equal diameter inner hole design of the hollow shaft, the single-point eddy current probe cannot fit tightly inside the hollow shaft during the detection process; therefore, the linear Hall sensor 3 of the present application obtains the magnetic induction change of the induction coil to judge the distance between the electromagnetic array eddy current sensor 2 and the inner wall of the hollow shaft, and then adjusts the position of the electromagnetic array eddy current sensor 2 according to the robotic arm 1, so that the electromagnetic array eddy current sensor 2 is close to the inner wall of the hollow shaft, thereby achieving the purpose of improving the detection sensitivity; at the same time, the present application adopts an elastic part structure on the linear Hall sensor to ensure that the electromagnetic array eddy current sensor can maintain a tight fit with the inside of the hollow shaft. Since the detection device of the present application scans the hollow shaft with a non-equal diameter inner hole structure, compared with the traditional single-point eddy current probe, it has high detection efficiency and detection accuracy, and is more flexible and simple to operate.

[0040] like Figure 4 As shown, in one embodiment, the electromagnetic array eddy current sensor 2 includes an S-shaped array coil assembly 21, the S-shaped array coil assembly 21 includes a four-element detection array 211 and a three-element detection array 212, and the four-element detection array 211 and the three-element detection array 212 form a spatial phase difference distribution structure.

[0041] In this way, the S-shaped array coil assembly 21 includes a four-element detection array 211 and a three-element detection array 212, forming a spatial phase difference distribution. A spiral progressive detection path is constructed by the embedded arrangement of the three-element detection array 212 in the gap of the four-element detection array 211. Each sensing unit on the three-element detection array 212 and the four-element detection array 211 adopts equal parameter design to ensure the consistency of the detection field strength, and the magnetic core is optimized after magnetic domain orientation treatment to achieve magnetic circuit optimization.

[0042] like Figure 3 As shown, in one embodiment, the mounting assembly 5 includes a mounting base 51 and at least two support columns 52. The mounting base 51 is fixedly or detachably mounted on the electromagnetic array eddy current sensor 2. One end of the support column 52 is inserted through the mounting base 51 and the other end is mounted on the linear Hall sensor 3. The mounting base 51 can slide along the support column 52. The elastic member 6 is mounted on the support column 52 and its ends respectively abut the mounting base 51 and the linear Hall sensor 3. The mounting base 51 and the two support columns 52 are connected by an interference fit. There can be four support columns 52, which are centrally symmetrically arranged on the mounting base 51.

[0043] Thus, when the electromagnetic array eddy current sensor 2 is detecting within the hollow shaft, the linear Hall sensor 3 is driven by the robotic arm 1. The linear Hall sensor 3, via the mounting base 51 and at least two support posts 52, constantly pushes the electromagnetic array eddy current sensor 2 into contact with the inner wall of the hollow shaft, thereby ensuring detection sensitivity and accuracy. Simultaneously, the elastic member 6 is sleeved onto the support posts 52, with its ends respectively contacting the mounting base 51 and the linear Hall sensor 3, thereby avoiding hard contact between the mounting base 51 and the linear Hall sensor 3, and also avoiding hard contact between the electromagnetic array eddy current sensor 2 and the inner wall of the hollow shaft. When the electromagnetic array eddy current sensor 2 is no longer in contact with the inner wall of the hollow shaft, the elastic member 6 can be restored to its original shape, thereby resetting the electromagnetic array eddy current sensor 2.

[0044] In one embodiment, the linear Hall sensor 3 is mounted on the robotic arm through a mounting tube 7, which is a hollow structure; one end of the mounting tube 7 has a mounting hole 71, and there are two mounting holes 71, which are symmetrically arranged on the outer wall of one end of the mounting tube 7; the linear Hall sensor 3 has a mounting portion 31, and the mounting portion 31 has a receiving hole 311, and the mounting tube 7 is inserted into the receiving hole 311, and the mounting portion 31 has a fixing hole 312. When the mounting tube 7 is inserted into the receiving hole 311, the fixing hole 312 and the mounting hole 71 are aligned with each other and connected, and the external connector is sequentially inserted into the fixing hole 312 and the mounting hole 71; the robotic arm 1 has a fixed shaft sleeve 8 at one end close to the mounting tube 7, and the fixed shaft sleeve 8 can be detachably installed on the robotic arm 1, and the mounting tube 7 is inserted into the fixed shaft sleeve 8.

[0045] In this way, one end of the mounting tube 7 is inserted into the fixed shaft sleeve 8 of the robotic arm 1, and the other end is inserted into the accommodating hole 311, so that the fixing hole 312 and the mounting hole 71 are aligned with each other and connected, and the external connector is inserted into the fixing hole 312 and the mounting hole 71 in turn. The linear Hall sensor 3 can be detachably installed on the robotic arm 1. When the linear Hall sensor 3 needs to be removed from the robotic arm 1, the external connector can be pulled out from the fixing hole 312 and the mounting hole 71 in turn, and the disassembly and assembly are simple and convenient.

[0046] The above are only preferred specific implementation methods of the present application, but the scope of protection of the present application is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes based on the technical solution and inventive concept of the present application within the technical scope disclosed in the present application, and they should be covered by the scope of protection of the present application.

Claims

1. A device for detecting inner hole defects of non-uniform hollow shafts, characterized by: It includes a robotic arm, an electromagnetic array eddy current sensor, a linear Hall sensor, and an intelligent eddy current detector. The robotic arm is responsible for receiving control instructions and adjusting the detection posture of the electromagnetic array eddy current sensor according to the control instructions. The linear Hall sensor is detachably mounted on the robotic arm and is used to detect the fit between the electromagnetic array eddy current sensor and the inner wall of the hollow shaft. The electromagnetic array eddy current sensor is movably mounted on the linear Hall sensor along the axial direction through the mounting assembly. The intelligent eddy current detector is arranged on one side of the robotic arm and is used to obtain detection data of the electromagnetic array eddy current sensor and transmit the detection data to the host computer for imaging of the detection results. An elastic member is sleeved on the mounting assembly, and the two ends of the elastic member are respectively in contact with the mounting assembly and the linear Hall sensor. The electromagnetic array eddy current sensor includes an S-shaped array coil assembly, which includes a four-element detection array and a three-element detection array. The four-element detection array and the three-element detection array form a spatial phase difference distribution structure.

2. The device for detecting inner hole defects of non-uniform hollow shafts according to claim 1, characterized in that: The robotic arm is a six-degree-of-freedom robotic arm, which includes six rotational joints.

3. The device for detecting inner hole defects of non-uniform hollow shafts according to claim 1, characterized in that: The mounting assembly includes a mounting base and at least two support columns. The mounting base is fixedly or detachably mounted on the electromagnetic array eddy current sensor. One end of the support column is passed through the mounting base, and the other end is mounted on the linear Hall sensor. The mounting base can slide along the support column. The elastic member is sleeved on the support column and its two ends are respectively in contact with the mounting base and the linear Hall sensor.

4. The device for detecting inner hole defects of non-uniform hollow shafts according to claim 3, characterized in that: The mounting base and the two support columns are interference connected.

5. The device for detecting inner hole defects of non-uniform hollow shafts according to claim 3, characterized in that: The elastic member is a spring.

6. The device for detecting inner hole defects of non-uniform hollow shafts according to claim 1, characterized in that: The linear Hall sensor is installed on the robotic arm through a mounting tube, and the mounting tube is a hollow structure.

7. The device for detecting inner hole defects of non-uniform hollow shafts according to claim 6, characterized in that: One end of the mounting tube is provided with a mounting hole, and there are two mounting holes which are symmetrically arranged on the outer wall of one end of the mounting tube.

8. The device for detecting inner hole defects of non-uniform hollow shafts according to claim 7, characterized in that: The linear Hall sensor has a mounting portion with a receiving hole formed on the mounting portion. The mounting tube is inserted into the receiving hole. A fixing hole is formed on the mounting portion. When the mounting tube is inserted into the receiving hole, the fixing hole and the mounting hole are aligned with each other and connected. The external connector is inserted into the fixing hole and the mounting hole in sequence.

9. The device for detecting inner hole defects of non-uniform hollow shafts according to claim 8, characterized in that: One end of the robotic arm close to the mounting tube is provided with a fixed shaft sleeve, the fixed shaft sleeve is detachably mounted on the robotic arm, and the mounting tube is plugged into the fixed shaft sleeve.

Images