Crankshaft defect detection mechanism and system based on progressive scanning

Abstract

The invention belongs to the field of automobile engine crankshaft defect detection imaging, and aims to solve the problems of low detection efficiency, easy misjudgment due to view limitation, difficult identification of microcracks caused by incapability of synchronously tracking crankshaft rotation, no self-protection due to crankshaft placement deviation and the like in the existing artificial magnetic powder inspection. The core of the invention is a crankshaft defect detection mechanism based on line-by-line scanning, and the crankshaft defect detection mechanism comprises a crankshaft follow-up mechanism and a signal control system: the crankshaft follow-up mechanism is based on a base and is provided with five fixed brackets for constraining a servo motor, two follow-up crankshafts and a detected crankshaft, and a follow-up bracket is provided with a gear transmission mechanism for ensuring the synchronous operation of a linear array camera and the detected crankshaft; the two follow-up crankshafts, the I-shaped beam rod body and the connecting rod large end jointly form a horizontal mechanism, meanwhile, a signal control panel shell is built, cameras are fixed to the I-shaped beam rod body and the connecting rod large end, a light supplementing lamp is installed at the tail end of the panel shell, and a detected crankshaft main journal is collected through a fixed line-scan digital camera. The signal control system comprises a power supply, a line-scan digital camera, an ADC analog-to-digital module, an MCU control module and the like. The detection efficiency and accuracy can be improved, and the assembly rhythm of a production line is met.

Description

Technical Field

[0001] This invention relates to the field of imaging technology for detecting crankshaft defects in automobile engines, and in particular to a crankshaft defect detection mechanism and system based on line-by-line scanning. Background Technology

[0002] In the mass production quality inspection of automotive engines, the crankshaft, as a core component for power transmission, directly determines the safety of engine operation due to its surface quality. Especially when inspecting for micro-cracks on the surface of the crankshaft main journals and connecting rod journals, operators typically need to move the crankshaft to a testing table, apply a magnetic suspension to each journal section using magnetic particle testing, and then observe the magnetic traces section by section using ultraviolet light to determine the presence of cracks. However, existing surface defect inspections usually require manual operation, and manually completing a full surface inspection of a crankshaft takes 3-5 minutes or even longer, which cannot meet the assembly rhythm of the production line. Furthermore, when using a handheld endoscope, the limited field of vision makes it easier to misjudge crankshaft quality, thus affecting the post-assembly quality and overall test results.

[0003] Therefore, a control system is needed that can achieve crankshaft journal surface imaging through a follow-up system that assists in imaging with a linear array camera, while ensuring that the system automatically stops and corrects itself in the event of an unexpected situation. Summary of the Invention

[0004] This invention aims to provide a servo system that enables a linear array camera to dynamically rotate with the crankshaft surface and a control system to handle emergencies. The core solution is to address the problem that defects such as cracks and production damage cannot be accurately identified due to the limited field of view and the inability to synchronously track crankshaft rotation, as well as the problem of automatic stopping and prompting in cases of crankshaft misalignment. Ultimately, it ensures clear imaging of the entire crankshaft surface without blind spots and guarantees economic efficiency and personnel safety, laying the foundation for accurate defect identification in the future.

[0005] The technical scheme adopted by the present application is: a crankshaft defect detection mechanism and system based on line-by-line scanning, comprising a line-by-line scanning crankshaft defect detection mechanism and a signal control system: the crankshaft follow-up mechanism comprises a base, fixed supports are arranged on the base to respectively fix a servo motor and a crankshaft journal; a torque transmission mechanism is also installed on the fixed supports to realize synchronous operation of a camera mounting table and a target crankshaft; the camera mounting table is composed of two crankshafts of the same type as the measured crankshaft, and the camera is fixed on the corresponding crankshaft journal by cooperating with an I-beam shaft and a connecting rod big end; the signal control system comprises a power module, which provides power supply for the entire signal control system; a sensor, which collects received optical signals and converts them into corresponding voltage values; an analog-digital module, which converts collected sensor analog signals into digital signals; a communication module, which transmits data of the digital signals to an upper computer; an MCU control module, which processes signals transmitted by the analog-digital module and outputs control signals to the communication module and the motor control module; a user interaction module, which transmits obtained video streams and sends them to the upper computer; and a motor control module, which controls the start and stop of the servo motor and simultaneously sends corresponding feedback signals to the control module.

[0006] According to a preferred embodiment, a plurality of fixed supports are connected to the base by bolts, and the fixed supports for placing the measured crankshaft have a certain height difference with the follow-up crankshaft.

[0007] According to a preferred embodiment, the torque transmission mechanism is installed with synchronous wheels and synchronous tooth belts of a certain transmission ratio according to the rotation rate of the motor, and is installed on one side of the fixed supports of the measured crankshaft and the follow-up crankshaft, respectively.

[0008] According to a preferred embodiment, the camera mounting platform determines the end face installation of the driving bearing and the driven bearing according to the required crankshaft, the rotation direction and the observation target, and simultaneously ensures that the measured crankshaft is connected according to the same installation direction.

[0009] According to a preferred embodiment, the connecting rod mechanism and the connecting plate are installed on the journal of the corresponding camera mounting table according to the journal surface to be observed, so as to ensure that the camera is 5-10 mm away from the observed journal.

[0010] According to a preferred embodiment, the communication module, the analog-digital module, the motor control module, the MCU control module and the sensor module are connected to the power module, respectively. The MCU control module is connected to the communication module, the user interaction module, the analog-digital module and the motor control module, respectively. The sensor is connected to the analog-digital module. BRIEF DESCRIPTION OF DRAWINGS

[0011] The application will be further described in conjunction with the accompanying drawings and related design flowcharts.

[0012] Fig. 1 is a schematic diagram of the overall structure of a crankshaft defect detection mechanism and system based on line-by-line scanning according to the present application;

[0013] Fig. 2 is a top view of a crankshaft defect detection mechanism and system based on line-by-line scanning according to the present application;

[0014] Fig. 3 is a side view of a crankshaft defect detection mechanism and system based on line-by-line scanning according to the present application;

[0015] Fig. 4 is a schematic diagram of the signal control structure of a crankshaft defect detection mechanism and system based on line-by-line scanning according to the present application;

[0016] In the figure: 1, servo motor; 2, motor fixed support; 3, synchronous belt; 4, first measured crankshaft fixed support; 5, transmission gear; 6, first linear array camera; 7, second measured crankshaft fixed support; 8, measured crankshaft; 9, light supplement lamp; 10, second linear array camera; 11, signal control board shell; 12, I-beam shaft; 13, first follow-up crankshaft; 14, coupling key; 15, connecting rod big end; 16, second follow-up crankshaft; 17, base; 18, follow-up fixed support; 19, crankshaft end bearing; 20, signal control system; which includes: 201, power module; 202, motor control module; 203, analog-digital module; 204, MCU control module; 205, communication module; 206, user interaction module; 207, sensor. DETAILED DESCRIPTION

[0017] The embodiments of the present application will be described in detail below, and the example diagrams of these embodiments are all shown in the accompanying drawings, wherein the same or similar reference signs represent the same or similar elements with similar functions. The description of these embodiments by referring to the accompanying drawings is exemplary, and its purpose is to explain the present application, but not as a limitation to the present application.

[0018] Please refer to Figs. 1 to 3The application provides a crankshaft defect detection mechanism and system based on line-by-line scanning, which comprises a base 17; five support fixing supports are arranged on the base 17, mainly including a motor fixing support 2, a first measured crankshaft fixing support 4, a second measured crankshaft fixing support 7 and a follow-up fixing support 18, which are respectively used for fixing a servo motor 1, a synchronous belt 3, a transmission gear 5, a measured crankshaft 8, a first follow-up crankshaft 13 and a second follow-up crankshaft 16. Among them, the motor fixing support 2 is used for fixing the servo motor 1 through bolts, the motor is connected with the transmission gear 5 through a shaft coupling, and the transmission gear 5 provides power for the first follow-up crankshaft 13, the second follow-up crankshaft 16 and the measured crankshaft 8; the follow-up fixing support 18 is used for fixing the first follow-up crankshaft 13 and the second follow-up crankshaft 16, and the transmission gear 5 is fixed in an interference fit mode; taking the transmission gear 5 as an example, similar transmission gears adopt the same connection and fixing mode, the synchronous belt is meshed with a toothed groove of a pulley through a tooth shape, and relative sliding between gears can be avoided; the first measured crankshaft fixing support 4 is installed with a driven bearing, so as to reduce power consumption of the servo motor, and ensure the simultaneity of rotation speed and rotation direction; taking the second measured crankshaft fixing support 7 as an example, similar installation modes are adopted for the same or similar parts, and the parts are used for installing synchronous transmission crankshaft end bearings 19 of the measured crankshaft 8;

[0019] Preferably, the transmission gear 5 is fixed on an output shaft of the servo motor 1 through a shaft coupling, the outer side is fastened and limited by bolts, the transmission gear 5 is installed at the front end of the two first follow-up crankshafts 13 and the second follow-up crankshafts 16 and the measured crankshaft 8, the gear and the front end of the crankshaft are fastened by three groups of diagonal bolts, the sliding in the rotation process is avoided, and the accuracy of synchronous detection is ensured; the transmission gears 5 are connected through synchronous toothed belts, and it is necessary to ensure that the two gears connected by the synchronous toothed belts are in the same vertical plane, so as to ensure high transmission accuracy.

[0020] Preferably, the main bearing necks of the first follow-up crankshaft 13, the second follow-up crankshaft 16 and the measured crankshaft 8 are fixed in an interference fit mode, and the front ends are fixed with bearings in the first measured crankshaft fixing support 4 and the follow-up fixing support 18; further preferably, the second measured crankshaft fixing support 7 is adopted to ensure that the first follow-up crankshaft 13 and the second follow-up crankshaft 16 do not limit each other when rotating synchronously; when the measured crankshaft 8 is assembled, it is necessary to ensure that the first follow-up crankshaft 13 and the second follow-up crankshaft 16 have a certain phase difference with the measured crankshaft, so that the crankpin neck of the measured crankshaft can be clearly identified when a camera is assembled later.

[0021] Preferably, on the connecting rod journal of the first and second follow-up crankshafts 13 and 16, the I-beam shaft 12 and the connecting rod big end 15 matched with the model of the measured crankshaft 8 are assembled to further ensure the synchronous operation of the first and second follow-up crankshafts 13 and 16, and to improve the structural bearing capacity and provide a stable foundation for the assembly of the linear array camera; wherein the same elements as the connecting rod big end 15 need to be correspondingly assembled with two elements of the same model as the connecting key 15 to ensure that the overall structure has high tensile and shear resistance. Further preferably, the signal control board shell 11 is installed at the end of the I-beam shaft 12 to avoid damage and falling of the signal wire harness and power wire harness of the camera during the rotation of the crankshaft; at the same time, the fill light 9 needs to be installed at the end of the signal control board shell 11 to provide real-time fill light function when the follow-up system is running, and to realize clear image acquisition of the second linear array camera 10; in addition, the second linear array camera 10 needs to be fixed on the signal control board shell 11 by bolt connection to ensure that the linear array camera can be assembled in a stable and horizontal state. For the crankshaft main journal part of the measured crankshaft 8, the first linear array camera 6 is fixedly installed for fixed acquisition.

[0022] The signal control system 20 in the application includes a power module 201, a motor control module 202, an analog-digital module 203, an MCU control module 204, a communication module 205, a user interaction module 206 and a sensor 207. The analog-digital module 203, the MCU control module 204, the MCU control module 204, the communication module 205, the user interaction module 206 and the sensor 207 are respectively connected with the power module 201; the motor control module 202, the analog-digital module 203, the communication module 205 and the user interaction module 206 are sequentially connected with the MCU control module 204; and the sensor 207 is connected with the analog-digital module 203.

[0023] The power module 201 is used to provide driving power for the analog-digital module 203, the motor control module 202, the MCU control module 204, the communication module 205 and the user interaction module 206.

[0024] The sensor 207 is used to convert the collected external light signal into a voltage signal.

[0025] The analog-digital module 203 is used to collect the voltage signal and convert the analog quantity into a digital signal.

[0026] The motor control module 202 is used to control the start and stop operation of the servo motor, and adjust the rotating speed and direction according to the upper computer or the user interaction module.

[0027] The MCU control module 204 is used for collecting data of each module and outputting specified control signals to corresponding modules to realize corresponding functions.

[0028] The communication module 205 is used for realizing information transmission between the MCU and the host computer.

[0029] The user interaction module 206 is used for transmitting user control signals to the MCU control module and transmitting control signal feedback signals to the user interaction module 204 for display.

[0030] In the embodiment, the sensor 207 adopts a linear array image sensor as a collection core component, which is used for converting external incident light signals into voltage signals; the analog-digital module 203 is an ADC module, which is responsible for converting the voltage signals into digital signals and transmitting the digital signals to the MCU control module 204. The MCU control module 204 performs filtering processing on the collected digital signals containing noise, adopts a first-order low-pass filtering algorithm, and suppresses high-frequency signal interference in the collection or transmission process. The core formula used is as follows:

[0031] y k =a*x k +(1+a)*y k-1

[0032] In the formula, x k represents the original sampling value at time k, which contains the collected high-frequency interference signal, y k represents the filtering output value at time k, i.e., the waveform data after filtering, y k-1 represents the filtering output value at time k-1, and a represents a filtering coefficient, which is in a range of 0 to 1, and the coefficient determines the smoothing degree of filtering. The above algorithm is used to filter out the interference signal, and then the filtered signal is transmitted to the host computer control system through the communication module 205. This process realizes the complete link of electronic signal from preliminary collection to system transmission, and provides basic support for the imaging of the linear array camera.

[0033] Further, the MCU control module 204 realizes the start control of the servo motor through the motor control module 202: the user sends a control signal to the MCU control module 204 through the user interaction module 206, and after signal processing, the rotation speed and rotation direction of the servo motor can be accurately controlled; at the same time, the motor control module 202 can receive the speed and rotation direction information of the motor itself in real time and send the data to the MCU control module 204, and if an abnormal situation occurs, the motor and the part can be automatically corrected or triggered to stop, to ensure the safety of the motor and the part.

[0034] The principle of the crankshaft follow-up system of the present application is as follows: two reference crankshafts of the same type as the measured crankshaft are adopted, the connecting rod shaft necks at the corresponding positions of the two reference crankshafts are connected by connecting rods, the connecting rod shaft neck centers of the two reference crankshafts and the shaft neck centers of the two reference crankshafts themselves form a virtual parallelogram motion chain, and a linear array camera is precisely installed on the motion chain platform. In order to ensure that the camera optical axis and the surface of the measured connecting rod shaft neck always maintain accurate relative positions, that is, to realize the follow-up function, the system transmits the power of the servo motor to the measured crankshaft and the two reference crankshafts at the same time and in equal proportions through a precisely designed synchronous belt transmission system, so as to strictly ensure that the rotation speed and angular phase of the measured crankshaft and the two reference crankshafts are completely synchronized. For the main shaft neck and the balance block area, because the geometric shape is relatively simple and the position change law relative to the fixed reference system in the rotation process is clear, the system adopts a fixed position imaging scheme. The mechanism allows the operator or the control system to finely adjust the position of the camera in the horizontal plane within a small range to obtain the best imaging effect.

[0035] The present application is not limited to the above-mentioned optional embodiments, and anyone can obtain various forms of products under the inspiration of the present application. However, regardless of any changes in shape or structure, any technical solution falling within the scope defined by the claims of the present application belongs to the protection scope of the present application. Those skilled in the art should understand that the specification and drawings of the present application are only for illustrative purposes, and do not constitute a limitation on the claims. The protection scope of the present application is defined by the claims and their equivalents. In the entire text, the features introduced by "preferably" are only optional ways, and should not be understood as mandatory settings, therefore, the applicant reserves the right to abandon or remove the related preferred features at any time.

Claims

1. A crankshaft defect detection mechanism and system based on line-by-line scanning, including a crankshaft defect detection mechanism based on line-by-line scanning and a signal control system: the crankshaft follower mechanism includes a base (17), on which five fixed supports are provided to constrain the servo motor (1), the first follower crankshaft (13), the second follower crankshaft (16) and the crankshaft under test (8) respectively; a synchronous wheel transmission mechanism is also installed on the follower fixed support (18) to realize the synchronous operation of the line array camera (10) and the crankshaft under test (8); the I-beam rod body (14) is connected to the connecting rod big end (15) and together with two crankshafts of the same model as the crankshaft under test, they form a horizontal mechanism, and at the end of the I-beam rod body (14), a signal control plate shell (11) is mounted; and the signal control plate shell (11) can be connected to the second line array camera (10) by bolts. The signal control system (20) includes a power supply module (201), a sensor (207), an analog-to-digital module (203), a communication module (205), an MCU control module (204), a user interaction module (206), and a motor control module (202). The power supply module (201) provides power to the entire signal control system. The sensor (207) is used to collect optical signals and convert them into corresponding voltage values. The analog-to-digital module (203) is used to convert the analog signals output by the sensor (207) into digital signals. The communication module (205) is used to transmit the digital signals to the host computer. The MCU control module (204) is used to process the signals transmitted by the analog-to-digital module (203) and output control signals to the communication module (205) and the motor control module (202). The user interaction module (206) is used to control the output video stream. The motor control module (202) is used to control the start and stop of the servo motor (1) and send corresponding feedback signals to the MCU control module (204).

2. The crankshaft defect detection mechanism based on line-by-line scanning according to claim 1, characterized in that, All five fixed brackets are bolted to the base (17); the fixed brackets for placing the crankshaft under test (8) create a height difference between the crankshaft under test (8) and the first follower crankshaft (13) and the second follower crankshaft (16).

3. The crankshaft defect detection mechanism based on line-by-line scanning according to claim 1, characterized in that, The gear transmission mechanism is equipped with a synchronous pulley and a synchronous toothed belt with a specific transmission ratio according to the rotation speed of the servo motor (1). The synchronous pulley and the synchronous toothed belt are respectively installed on one side of the fixed bracket corresponding to the crankshaft under test (8) and the first follower crankshaft (13) and the second follower crankshaft (16).

4. The crankshaft defect detection mechanism based on line-by-line scanning according to claim 1, characterized in that, The horizontal mechanism, which is composed of the first follower crankshaft (13), the second follower crankshaft (16), the I-beam rod body (14) and the connecting rod big end (15), has a drive bearing and a driven bearing installed on the end face according to the rotation direction of the crankshaft and the observation requirements. The crankshaft under test (8) is installed in the same installation direction as the horizontal mechanism.

5. The crankshaft defect detection mechanism based on line-by-line scanning according to claim 1, characterized in that, The I-beam shaft (14) and the connecting rod big end (15) are installed on the journals corresponding to the first follower crankshaft (13) and the second follower crankshaft (16) according to the journal surface to be observed, and the line array camera (10) is at an appropriate distance from the journal to be observed.

6. The crankshaft defect detection mechanism based on line-by-line scanning according to claim 1, characterized in that, The transmission gear (5) in the gear transmission mechanism is fixed to the output shaft of the servo motor (1) by a coupling. The transmission gear (5) is fastened and limited by bolts on the outside. The transmission gears are respectively installed at the front ends of the first follower crankshaft (13), the second follower crankshaft (16) and the crankshaft under test (8). The transmission gears are fastened to the front ends of each crankshaft by three sets of diagonal bolts. The transmission gears (5) are connected by a synchronous belt (3), and the two transmission gears connected by the synchronous belt (3) are in the same vertical plane.

7. The crankshaft defect detection mechanism based on line-by-line scanning according to claim 1, characterized in that, The main bearing journals of the first follower crankshaft (13), the second follower crankshaft (16), and the crankshaft under test (8) adopt an interference fit, and their front ends are fixed to the bearings in the corresponding fixed brackets; the fixed brackets used to install the crankshaft under test (8) ensure that the first follower crankshaft (13) and the second follower crankshaft (16) do not mutually limit each other when rotating synchronously; when assembling the crankshaft under test (8), the first follower crankshaft (13), the second follower crankshaft (16) and the crankshaft under test (8) maintain a certain phase difference.

8. The crankshaft defect detection mechanism based on line-by-line scanning according to claim 1, characterized in that, On the connecting rod journals of the first follower crankshaft (13) and the second follower crankshaft (16) equipped with the second line array camera (10), an I-beam rod body (14) matching the model of the crankshaft under test (8) and a connecting rod big end (15) are assembled; the end of the I-beam rod body (14) is equipped with a signal control plate housing (11), and a supplementary light (9) is installed at the end of the signal control plate housing (11); the second line array camera (10) is fixed on the signal control plate housing (11) by bolt connection; the crankshaft main journal of the crankshaft under test (8) is fixedly collected by the first line array camera (6) that is fixedly installed.

9. The crankshaft defect detection mechanism based on line-by-line scanning according to claim 1, characterized in that, The first follower crankshaft (13) and the second follower crankshaft (16) are connected to the corresponding connecting rod journals through connecting rods, so that the center of the connecting rod journals of the two follower crankshafts and the center of their own journals form a virtual parallelogram motion chain. The second line array camera (10) is mounted on the motion chain platform. The gear transmission mechanism is equipped with a synchronous belt transmission system, which is used to transmit the power of the servo motor (1) to the crankshaft under test (8) and the first follower crankshaft (13) and the second follower crankshaft (16) simultaneously and proportionally, so as to ensure that the rotational speed and angular phase of the crankshaft under test (8) and the two follower crankshafts are synchronized. For the main journal and balance block area of ​​the crankshaft under test (8), a fixed position imaging scheme is adopted, and the position of the first line array camera (6) in the horizontal plane can be adjusted within a small range.

10. The signal control system (20) according to claim 1, characterized in that, The communication module (205), analog-to-digital module (203), motor control module (202), MCU control module (204), user interaction module (206), and sensor (207) are respectively connected to the power supply module (201); the MCU control module (204) is respectively connected to the communication module (205), user interaction module (206), analog-to-digital module (203), and motor control module (202); the signal control system also includes a sensor (207), which is connected to the analog-to-digital module (203).

11. The signal control system (20) according to claim 10, characterized in that, The sensor (207) is a linear array image sensor, and the analog-to-digital module (203) is an ADC module; the MCU control module (204) performs filtering algorithm processing on the digital signal transmitted by the analog-to-digital module (203) to filter out interference signals; the motor control module (202) receives the speed and steering information of the servo motor (1) in real time, and automatically corrects or triggers an emergency stop when an abnormality occurs.

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