Automatic distance changing method of automatic tightening shaft of cylinder head bolt automatic tightening machine

Abstract

The present application relates to the technical field of mechanical control, in particular to a kind of automatic tightening axle automatic distance changing method of cylinder head bolt automatic tightening machine, comprising: obtaining the model instruction of assembly station, wherein the model instruction is used to specify the target model of current engine to be assembled;According to model instruction, obtain the model code corresponding to target model from background database, wherein the model code is used to uniquely identify the assembly specification of target model;According to model code, call the tightening data matched with model code from central process database.The present application automatically matches model code through model instruction, calls bolt hole distance, tightening sequence and torque parameter from central process database, and drives sleeve replacement tool to automatically replace matched sleeve, controls servo motor to drive tightening head to move to each bolt target position, without manual adjustment of tightening axle distance or sleeve replacement, which greatly shortens product switching time.

Description

Technical Field

[0001] This invention relates to the field of mechanical control technology, specifically to an automatic pitch-changing method for the tightening shaft of an automatic cylinder head bolt tightening machine. Background Technology

[0002] Currently, traditional tightening machines require operators to manually change sleeves, manually adjust the tightening shaft spacing, or modify tightening parameters when dealing with different machine models. This results in long changeover times and is prone to misoperation leading to sleeve model mismatch or bolt hole spacing positioning deviation. Consequently, they cannot adapt to multi-variety mixed production lines and seriously affect the flexibility of the assembly line.

[0003] In addition, traditional methods tighten according to fixed parameters, do not collect torque data in real time to compare with the target value, and do not have an alarm function to stop when the tolerance is exceeded. Often, the torque is found to be unqualified only after tightening is completed, resulting in rework or missed inspection. At the same time, the tightening data is not automatically uploaded and saved, making it impossible to generate quality reports and historical traceability, making it difficult to analyze process problems. The pass rate and reliability of bolt tightening are low. Summary of the Invention

[0004] To achieve the above objectives, the present invention provides the following technical solution: a method for automatic pitch variation of the tightening shaft in an automatic cylinder head bolt tightening machine, comprising:

[0005] Obtain the model instruction of the assembly station, wherein the model instruction is used to specify the target model of the engine to be assembled; according to the model instruction, obtain the model code corresponding to the target model from the background database, wherein the model code is used to uniquely identify the assembly specifications of the target model;

[0006] Based on the machine model code, tightening data matching the machine model code is retrieved from the central process database. The tightening data includes bolt hole spacing data, tightening sequence data, and torque angle parameter data.

[0007] Based on the bolt hole distance data, control the tightening shaft to move to the sleeve replacement station, and drive the sleeve replacement fixture to disassemble the current sleeve and replace it with a target sleeve that matches the bolt hole distance data.

[0008] Based on the tightening sequence data and the torque angle parameter data, the tightening shaft is controlled to drive each servo motor to move the tightening head to the target position of each bolt corresponding to the bolt hole distance data, and the tightening shaft is locked after the movement is completed and a positioning signal is fed back.

[0009] Based on the torque angle parameter data, the tightening shaft is controlled to descend to the target sleeve to fit the corresponding bolt, and the tightening operation is performed sequentially according to the tightening sequence data.

[0010] Preferably, according to the model instruction, the model code corresponding to the target model is obtained from the background database, including:

[0011] When the engine enters the assembly station, the system receives the engine model instruction and performs a matching search in the background database according to the engine model instruction to obtain the engine model code corresponding to the target engine model. The engine model code includes the cylinder head structure identifier and bolt layout identifier of the target engine model.

[0012] Preferably, based on the machine model code, tightening data matching the machine model code is retrieved from the central process database, including:

[0013] Based on the cylinder head structure identifier in the model code, obtain the bolt hole distance data corresponding to the cylinder head structure identifier from the central process database;

[0014] Based on the bolt layout identifier in the model code, obtain the tightening sequence data corresponding to the bolt layout identifier from the central process database;

[0015] Based on the cylinder head structure markings and the bolt layout markings, torque angle parameter data matching the target engine model are obtained from the central process database.

[0016] Preferably, based on the bolt hole spacing data, the tightening shaft is controlled to move to the sleeve replacement station, and the sleeve replacement fixture is driven to disassemble the current sleeve and replace it with a target sleeve that matches the bolt hole spacing data, including:

[0017] The specification parameters of the target sleeve are determined based on the bolt hole spacing data, wherein the specification parameters include the sleeve inner diameter and the sleeve depth;

[0018] Control the tightening shaft to move to the disassembly position of the sleeve changing fixture, and drive the sleeve changing fixture to remove the current sleeve from the tightening head;

[0019] The robotic arm is controlled to place the disassembled sleeve replacement fixture onto the fixture rack and to pick up the fixture containing the target sleeve that matches the specified parameters.

[0020] Install the target sleeve onto the tightening head, and confirm that the installation is in place according to the specifications.

[0021] Preferably, based on the tightening sequence data and the torque angle parameter data, the tightening shaft drives each servo motor to move the tightening head to the target position of each bolt corresponding to the bolt hole distance data, and locks the tightening shaft and feeds back a positioning signal after the movement is completed, including:

[0022] Based on the coordinate information of each bolt in the bolt hole spacing data and the priority sorting of each bolt in the tightening sequence data, the movement path of the tightening head is generated.

[0023] Each servo motor is controlled to drive the tightening head to move sequentially to the target position of each bolt according to the moving path. When moving to each target position of a bolt, the position is calibrated according to the coordinate information of the bolt in the bolt hole distance data.

[0024] Once the tightening head moves to the target position of the last bolt, the tightening shaft is controlled to perform a locking action based on the locking torque parameter in the torque angle parameter data, and a positioning signal is generated.

[0025] Preferably, before controlling each servo motor to drive the tightening head to move sequentially to the target position of each bolt according to the said movement path, the method further includes:

[0026] Based on the distance information between adjacent bolts in the bolt hole distance data, calculate the movement time of the tightening head between the target positions of adjacent bolts;

[0027] Based on the tightening time parameters of each bolt in the torque angle parameter data, calculate the dwell time of the tightening head at the target position of each bolt;

[0028] Based on the movement time and the dwell time, a motion control timing sequence for each servo motor is generated, wherein the motion control timing sequence is used to coordinate the movement and dwell actions of the tightening head.

[0029] Preferably, based on the torque angle parameter data, the tightening shaft is controlled to move downwards to insert the target sleeve into the corresponding bolt, and the tightening operation is performed sequentially according to the tightening sequence data, including:

[0030] Based on the downward speed parameter in the torque angle parameter data, the tightening shaft is controlled to descend at a preset speed, wherein the preset speed is determined according to the tightening difficulty level of each bolt;

[0031] When the target sleeve contacts the corresponding bolt, the tightening head is controlled to apply an initial torque according to the initial torque parameter in the torque angle parameter data;

[0032] Based on the target torque and target angle values ​​of the current bolt in the tightening sequence data, the tightening head is controlled to complete the tightening of the current bolt according to the preset torque-angle curve;

[0033] Once the current bolt is tightened, the tightening shaft is moved to the target position of the next bolt according to the priority of the next bolt in the tightening sequence data, and the tightening operation is repeated until all bolts are tightened.

[0034] Preferably, after controlling the tightening shaft to move downwards according to the torque angle parameter data, inserting the target sleeve into the corresponding bolt, and performing the tightening operation sequentially according to the tightening sequence data, the method further includes:

[0035] The real-time torque data of the target sleeve during the tightening operation is acquired, wherein the real-time torque data is collected by a torque sensor on the tightening head;

[0036] The deviation value is obtained by comparing the real-time torque data with the target torque value in the torque angle parameter data;

[0037] If the deviation value exceeds a preset threshold, the tightening shaft is controlled to stop the tightening operation of the current bolt, and a tightening abnormality alarm signal is generated.

[0038] Preferably, after controlling the tightening shaft to stop the tightening operation of the current bolt and generating a tightening abnormality alarm signal when the deviation value exceeds a preset threshold, the method further includes:

[0039] Based on the tightening sequence data, determine the next priority bolt for the current bolt;

[0040] Control the tightening shaft to move to the target position of the next priority bolt, and perform the tightening operation of the next priority bolt according to the corresponding parameters in the torque angle parameter data;

[0041] After all bolts have been tightened, a tightening quality report is generated based on the real-time torque data. The tightening quality report includes a comparison between the actual torque value and the target torque value of each bolt.

[0042] Preferably, the method further includes:

[0043] After all bolts are tightened, the tightening shaft is controlled to return to the initial position, and the bolt hole spacing data, tightening sequence data, torque angle parameter data, and real-time torque data during this tightening process are uploaded to the background database according to the model code. The background database is used to record the tightening history data of the target model.

[0044] Compared with the prior art, the beneficial effects of the present invention are:

[0045] (1) The present invention automatically matches the model code through the model instruction, retrieves the bolt hole distance, tightening sequence and torque parameters from the central process database, and drives the sleeve changing tool to automatically change the matching sleeve, controls the servo motor to drive the tightening head to move to the target position of each bolt, without the need for manual adjustment of the tightening shaft distance or replacement of the sleeve, greatly shortens the product changeover time, adapts to multi-variety mixed production line production, and improves the flexibility and production efficiency of the engine assembly line;

[0046] (2) This invention uses tightening sequence data and torque angle parameters, adopts movement path and timing coordination control, and collects torque and target value in real time during the tightening process. If the deviation is exceeded, it will stop immediately and alarm, avoiding over-tightening or under-tightening defects. After all bolts are tightened, a quality report is generated, and the process parameters and real-time data are uploaded to the background database, realizing closed-loop monitoring and full traceability of tightening quality, effectively improving the pass rate and reliability of cylinder head bolt assembly. Attached Figure Description

[0047] Figure 1 This is a schematic flowchart of the overall method in one embodiment of the present invention. Detailed Implementation

[0048] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0049] Example 1, please refer to Figure 1 This invention provides a technical solution: an automatic torque-changing method for the tightening shaft of an automatic cylinder head bolt tightening machine, comprising:

[0050] S1. Obtain the model instruction of the assembly station, wherein the model instruction is used to specify the target model of the engine to be assembled; according to the model instruction, obtain the model code corresponding to the target model from the background database, wherein the model code is used to uniquely identify the assembly specifications of the target model;

[0051] S2. Based on the machine model code, retrieve the tightening data that matches the machine model code from the central process database. The tightening data includes bolt hole spacing data, tightening sequence data, and torque angle parameter data.

[0052] S3. Based on the bolt hole distance data, control the tightening shaft to move to the sleeve replacement station, and drive the sleeve replacement fixture to disassemble the current sleeve and replace it with the target sleeve that matches the bolt hole distance data.

[0053] S4. Based on the tightening sequence data and torque angle parameter data, control the tightening shaft to drive each servo motor to move the tightening head to the target position of each bolt corresponding to the bolt hole distance data, and lock the tightening shaft after the movement is completed and feed back the position signal.

[0054] S5. Based on the torque and angle parameter data, control the tightening shaft to move downwards and insert the target sleeve into the corresponding bolt, and perform the tightening operation in sequence according to the tightening sequence data.

[0055] It should be noted that on a certain engine assembly line, the cylinder head bolt automatic tightening machine received the engine type instruction "Model A" from the production line control; this instruction indicates that the engine to be assembled is a 6-cylinder diesel engine; based on the engine type instruction, the corresponding engine type code "D6-24" was found in the background database; this code uniquely identifies the assembly specifications of this engine type;

[0056] Retrieve tightening data matching model code D6-24 from the central process database: Bolt hole spacing data includes the coordinate sequence of 10 bolt holes on the cylinder head plane in the X and Y directions, with adjacent hole spacings of 85 mm, 85 mm, 90 mm, 85 mm, etc.; Tightening sequence data is the path of cross tightening from the middle to both sides; Torque angle parameter data includes a first-stage torque of 30 Nm, a second-stage torque of 80 Nm, and a final torque of 150 Nm plus a 90-degree rotation.

[0057] Based on the bolt hole spacing data, the tightening machine controller drives the servo motor to move the tightening shaft to the sleeve replacement station. This station is equipped with a sleeve replacement fixture. The fixture recognizes that the current sleeve specification is 14 mm, while the target bolt is an M12 hexagonal head bolt, which needs to be replaced with a 12 mm sleeve. The fixture automatically disassembles the original sleeve, grabs and installs the 12 mm target sleeve.

[0058] According to the tightening sequence data and bolt hole distance data, the controller drives five servo motors to move each tightening axis to the target position corresponding to each bolt hole; for example, the position coordinates of the first bolt are X100 and Y50. During the movement, each axis is driven independently. After reaching the target position, the position sensor provides feedback that the axis is in place, the controller issues a locking command, and the position of each axis is locked and feedback a signal that it is in place.

[0059] The controller controls the tightening shaft to descend as a whole, based on torque and angle parameters, so that the target sleeve is fully fitted onto the bolt head. Then, according to the tightening sequence data, the tightening motors of each shaft are started sequentially. The first step is to pre-tighten with a torque of 30 Nm, the second step is to tighten again with a torque of 80 Nm, and finally, the final tightening is performed with a torque of 150 Nm and an angle of 90 degrees. During the tightening process, the torque and angle are monitored in real time. Once the parameters are qualified, a completion signal is issued, the tightening shaft is reset, and it waits for the next cylinder head assembly.

[0060] In an optional embodiment, according to the model instruction, retrieving the model code corresponding to the target model from the background database includes:

[0061] When the engine enters the assembly station, it receives the model instruction and performs a matching search in the background database according to the model instruction to obtain the model code corresponding to the target model. The model code includes the cylinder head structure identifier and bolt layout identifier of the target model.

[0062] It should be noted that when an engine to be assembled enters the assembly station of the automatic tightening machine along the conveyor line, the photoelectric sensor next to the station triggers a signal, notifying the control to read the current work order information. Upon receiving the engine model instruction, such as the string "LY6-180", the control immediately connects to the backend database and performs a matching search. The database stores records for all engine models, each record containing the engine name, model code, cylinder head structure identifier, and bolt layout identifier. Through comparison, the engine model code corresponding to LY6-180 is found to be D6-24. In this model code, the cylinder head structure identifier is D6, indicating that the engine is an inline 6-cylinder engine with locating pin holes and a cooling water jacket. The bolt layout identifier is 24, indicating that there are 24 bolt holes, symmetrically distributed in two rows, with a fixed hole spacing and arrangement. The model code D6-24 is extracted for subsequent retrieval of tightening data. If no match is found in the database, an error is reported and the line is paused, prompting manual intervention.

[0063] In an optional embodiment, retrieving tightening data matching the machine model code from a central process database, including:

[0064] Based on the cylinder head structure identifier in the model code, retrieve the bolt hole spacing data corresponding to the cylinder head structure identifier from the central process database;

[0065] Based on the bolt layout identifier in the model code, retrieve the tightening sequence data corresponding to the bolt layout identifier from the central process database;

[0066] Based on the cylinder head structure markings and bolt layout markings, obtain torque angle parameter data matching the target model from the central process database.

[0067] It should be noted that the obtained model code is D6-24, where the cylinder head structure identifier is D6 and the bolt layout identifier is 24. Connecting to the central process database, the bolt hole spacing data is first queried based on the cylinder head structure identifier D6. The database returns the following results: This cylinder head is an inline 6-cylinder cylinder, with a cylinder head length of 600 mm and a total of 24 bolt holes, arranged in two rows of 12. The hole spacing data is stored in a coordinate list format. The X coordinates of the first row of holes are 50, 85, 170, 255, 340, 425, 510, and 545 mm, respectively. The corresponding X coordinates for the second row are the same, while the Y coordinates are 30 mm and -30 mm, respectively.

[0068] Based on bolt layout identifier 24, the tightening sequence data is queried; the database returns: a strategy of alternating tightening from the middle to both sides is adopted; the sequence path is: starting from holes 12 and 13, gradually advancing towards both ends, and finally reaching the edge bolts at both ends; the specific sequence number corresponds to the predefined hole position;

[0069] By combining the cylinder head structure marking D6 and bolt layout marking 24, the torque and angle parameter data are matched; the database returns: the first step pre-tightening torque is 30 N·m, the second step final tightening torque is 150 N·m, plus a 90-degree rotation angle, and the tightening speed is controlled at 10 degrees per second; in addition, the angle monitoring tolerance is ±3 degrees; these three parts of data are combined into complete tightening data for subsequent sleeve replacement and tightening operations.

[0070] In an optional embodiment, based on bolt hole spacing data, the tightening shaft is controlled to move to the sleeve replacement station, and the sleeve replacement fixture is driven to disassemble the current sleeve and replace it with a target sleeve that matches the bolt hole spacing data, including:

[0071] The specifications of the target sleeve are determined based on the bolt hole spacing data, including the sleeve inner diameter and sleeve depth.

[0072] Control the tightening shaft to move to the disassembly position of the sleeve changing fixture, and drive the sleeve changing fixture to remove the current sleeve from the tightening head;

[0073] The robotic arm is controlled to place the disassembled sleeve replacement fixture onto the fixture rack and to pick up the fixture containing the target sleeve that matches the specifications.

[0074] Install the target sleeve onto the tightening head and confirm that it is installed correctly according to the specifications.

[0075] It should be noted that, based on the bolt hole spacing data, the bolt to be tightened is determined to be M12. Therefore, the target sleeve specifications are retrieved from the database: sleeve inner diameter 12 mm, sleeve depth 25 mm. The tightening shaft is controlled to move along the guide rail to directly below the sleeve replacement fixture, i.e., the disassembly position. The grippers of the sleeve replacement fixture rise and lock the 14 mm sleeve currently mounted on the tightening head, and the pneumatic mechanism pulls the sleeve out. After disassembly, a six-axis robotic arm is controlled to move to the fixture stand, and the pneumatic gripper at the end of the robotic arm... The tooling holding the old sleeve is removed from the tooling changer and placed in the storage position of the tooling rack. Then, the robotic arm picks up a new tooling pre-loaded with a target sleeve with an inner diameter of 12 mm and a depth of 25 mm from another area of ​​the tooling rack and installs it onto the interface of the sleeve changing tooling. Subsequently, the changing tooling rises to align with the tightening head, pushes the target sleeve into the tightening head and locks it in place. The sensor inside the tightening head detects the sleeve's positioning signal, confirms the installation is complete, and then controls the tightening shaft to leave the changing station and enter the standby state.

[0076] In an optional embodiment, based on tightening sequence data and torque angle parameter data, the tightening shaft drives each servo motor to move the tightening head to the target position of each bolt corresponding to the bolt hole distance data, and locks the tightening shaft and feeds back a positioning signal after the movement is completed, including:

[0077] Based on the coordinate information of each bolt in the bolt hole spacing data, and combined with the priority sorting of each bolt in the tightening sequence data, the movement path of the tightening head is generated.

[0078] Each servo motor is controlled to drive the tightening head to move sequentially to the target position of each bolt according to the movement path. When moving to the target position of each bolt, the position is calibrated according to the coordinate information of the bolt in the bolt hole distance data.

[0079] Once the tightening head moves to the target position of the last bolt, the tightening shaft is controlled to perform a locking action based on the locking torque parameter in the torque angle parameter data, and a positioning signal is generated.

[0080] It should be noted that after the cylinder head bolt automatic tightening machine completes the sleeve replacement, it obtains the coordinates of 24 bolts based on the bolt hole spacing data. For example, bolt No. 1 is X100, Y50, bolt No. 2 is X185, Y50, and so on. At the same time, the tightening sequence data specifies that the priority order is from the middle to both sides, that is, tighten bolts No. 12 and No. 13 first, and then tighten them outwards in sequence. Combining these two data, the tightening head's movement path is generated: first it moves to the vicinity of bolt No. 12's coordinates, then to bolt No. 13, then to bolts No. 11 and No. 14, and so on, forming a continuous path.

[0081] Each servo motor is controlled to drive the tightening head to move sequentially to the target position of each bolt according to the generated movement path; when each bolt position is reached, the position is calibrated using the coordinate information of the bolt, for example, by detecting the deviation between the center of the tightening head and the center of the bolt hole through a laser displacement sensor, and the servo motor is finely adjusted to make the two precisely aligned with a deviation of less than 0.5 mm.

[0082] Once the tightening head has moved to the target position of the last bolt, namely bolt number 1, and completed the calibration, the brake of the tightening shaft is controlled to actuate according to the preset locking torque parameter in the torque angle parameter data, such as 50 N·m, so that the tightening head is axially locked to prevent deviation during downward movement. At the same time, a positioning signal is generated to the controller via the bus, indicating that all tightening heads are in place and locked, allowing the next tightening operation to begin. Only after receiving the signal does the controller issue a downward command to start tightening the bolt.

[0083] In an optional embodiment, before controlling each servo motor to drive the tightening head to move sequentially to the target position of each bolt according to the movement path, the method further includes:

[0084] Based on the distance information between adjacent bolts in the bolt hole distance data, calculate the movement time of the tightening head between the target positions of adjacent bolts;

[0085] Based on the tightening time parameters of each bolt in the torque angle parameter data, calculate the dwell time of the tightening head at the target position of each bolt;

[0086] Based on the movement time and dwell time, motion control timing is generated for each servo motor. The motion control timing is used to coordinate the movement and dwell actions of the tightening head.

[0087] It should be noted that before the automatic tightening machine controls the movement of the tightening head, the movement time is first calculated based on the distance between adjacent bolts in the bolt hole distance data; for example, if the straight-line distance between bolt No. 12 and bolt No. 13 is 100 mm, and the tightening head's movement speed is set to 200 mm / s, then the movement time is 0.5 seconds; if the distance between bolt No. 13 and bolt No. 11 is 120 mm, the movement time is 0.6 seconds; the movement time is calculated for each adjacent position individually.

[0088] The dwell time is calculated based on the tightening time parameters of each bolt in the torque angle parameter data; for example, each bolt requires 0.8 seconds for pre-tightening and 1.5 seconds for final tightening, for a total dwell time of 2.3 seconds; some special bolts may require a longer time and should be handled separately.

[0089] Based on these movement and dwell times, motion control timing sequences for each servo motor are generated. The timing rules are as follows: starting from the starting position, the motor moves to the first target bolt, dwells for 2.3 seconds, then moves to the next bolt, dwells for 2.3 seconds, and so on. The start and stop times of each motor are precisely arranged to ensure that when the tightening head reaches a bolt, the corresponding servo axis of that bolt is already locked, while other axes are moving. This timing sequence achieves coordination between movement and dwell, avoids interference between axes, and improves tightening efficiency.

[0090] In an optional embodiment, based on torque angle parameter data, the tightening shaft is controlled to move downwards to insert the target sleeve into the corresponding bolt, and tightening operations are performed sequentially according to tightening sequence data, including:

[0091] Based on the downward speed parameter in the torque angle parameter data, the tightening shaft is controlled to descend at a preset speed, wherein the preset speed is determined according to the tightening difficulty level of each bolt;

[0092] When the target sleeve contacts the corresponding bolt, the tightening head is controlled to apply the initial torque according to the initial torque parameter in the torque angle parameter data;

[0093] Based on the target torque and target angle values ​​of the current bolt in the tightening sequence data, control the tightening head to complete the tightening of the current bolt according to the preset torque-angle curve;

[0094] After the current bolt is tightened, the tightening shaft is moved to the target position of the next bolt according to the priority of the next bolt in the tightening sequence data, and the tightening operation is repeated until all bolts are tightened.

[0095] It should be noted that the automatic cylinder head bolt tightening machine begins the tightening operation based on torque and angle parameter data. First, it reads the downward speed parameter, which is determined according to the tightening difficulty level of each bolt. For example, bolts near the edge of the water jacket are difficult to tighten due to the narrow space, so the downward speed is set to 5 mm / s; while bolts in the middle are easier to tighten, so the downward speed is set to 10 mm / s. The currently processed bolt number 12 is in the middle, and the tightening shaft descends vertically at a speed of 10 mm / s. When the target sleeve contacts the bolt head, the contact force sensor detects a sudden change in force and immediately reads the initial torque parameter as 10 N·m. It then controls the tightening head to apply this initial torque, so that the sleeve and bolt head are fully in contact.

[0096] Based on the target torque value of 150 N·m and the target angle value of 90 degrees for the current bolt in the tightening sequence data, the tightening head is controlled to tighten according to the preset torque-angle curve. The curve is divided into two stages: the first stage increases to 80 N·m at a constant torque rate while monitoring the angle; the second stage uses torque control and angle monitoring to rotate at an angular velocity of 15 degrees per second until it reaches 150 N·m and the cumulative rotation angle reaches 90 degrees. During the process, the torque and angle are recorded in real time, and an alarm is triggered if the deviation exceeds ±3%.

[0097] After completing bolt number 12, according to the tightening sequence data, the next bolt is bolt number 13. Control the tightening shaft to lift and move to the coordinate position of bolt number 13. Repeat the steps of going down, applying the initial torque, and tightening according to the torque angle curve. Repeat this cycle until all 24 bolts are tightened in sequence. After tightening, a completion signal is issued, the tightening shaft is reset, and it waits for the next workpiece.

[0098] In an optional embodiment, after controlling the tightening shaft to move downwards to fit the target sleeve onto the corresponding bolt according to the torque angle parameter data, and performing the tightening operation sequentially according to the tightening sequence data, the method further includes:

[0099] The real-time torque data of the target sleeve during the tightening operation is acquired, wherein the real-time torque data is collected by the torque sensor on the tightening head;

[0100] The deviation value is obtained by comparing the real-time torque data with the target torque value in the torque angle parameter data;

[0101] If the deviation exceeds the preset threshold, the tightening shaft will stop the tightening operation of the current bolt and generate a tightening abnormality alarm signal.

[0102] It should be noted that during the automatic tightening of a certain engine cylinder head bolt, the tightening head was performing final tightening on bolt number 8 according to the torque and angle parameters. The target torque value was 150 Nm, and the preset deviation threshold was ±5 Nm. The torque sensor on the tightening head collected data in real time, reading once every 0.1 seconds. When tightening to 140 Nm, the real-time torque was normal. When tightening to 153 Nm, the current torque of 153 Nm was compared with the target of 150 Nm, and the deviation value was +3 Nm, which was still within the 5 Nm range, so the tightening continued. When tightening to 156 Nm, the deviation reached +6 Nm, exceeding the preset threshold. The tightening shaft was immediately stopped from rotating, and an audible and visual alarm signal was issued. At the same time, the abnormal information was uploaded to the production management system, prompting the operator to check whether the bolt or the tightening head was abnormal. The bolt was marked as unqualified, and subsequent tightening was suspended to avoid damage to the threads due to excessive torque.

[0103] In an optional embodiment, after controlling the tightening shaft to stop the tightening operation of the current bolt and generating a tightening abnormality alarm signal when the deviation value exceeds a preset threshold, the method further includes:

[0104] Based on the tightening sequence data, determine the next priority bolt for the current bolt;

[0105] Control the tightening shaft to move to the target position of the next priority bolt, and execute the tightening operation of the next priority bolt according to the corresponding parameters in the torque angle parameter data;

[0106] After all bolts have been tightened, a tightening quality report is generated based on real-time torque data. The tightening quality report includes a comparison between the actual torque value and the target torque value of each bolt.

[0107] It should be noted that during the automatic tightening of a certain engine cylinder head bolt, bolt number 8 stopped tightening and triggered an alarm because its real-time torque exceeded a preset threshold. After recording this bolt anomaly, the next priority bolt (bolt number 9) was located based on the tightening sequence data. The tightening shaft was then moved from the position of bolt number 8 to the target position of bolt number 9. Normal tightening was then performed according to the target torque of 150 Nm and the target angle of 90 degrees corresponding to bolt number 9 in the torque-angle parameter data. After bolt number 9 was tightened, the remaining bolts were tightened sequentially until all 24 bolts were tightened. All bolts have been processed; after all bolts have been tightened, the real-time torque data recorded during the tightening process of each bolt is exported to generate a tightening quality report; the report lists the sequence number, target torque value, actual maximum torque value, and deviation value of each bolt in tabular form. For example, bolt No. 1 has a target torque of 150 N·m and an actual torque of 151 N·m, with a deviation of +1 N·m, which is acceptable; bolt No. 8 has a target torque of 150 N·m and an actual torque of 156 N·m, with a deviation of +6 N·m, which is unacceptable and marked as abnormal, so the process is stopped; this report is uploaded to the workshop management via Ethernet for quality engineers to trace and analyze.

[0108] In an optional embodiment, the method further includes:

[0109] After all bolts are tightened, the tightening shaft is controlled to return to the initial position, and the bolt hole spacing data, tightening sequence data, torque angle parameter data, and real-time torque data of this tightening process are uploaded to the background database according to the machine model code. The background database is used to record the tightening history data of the target machine model.

[0110] It should be noted that after all bolts are tightened, the automatic control tightening shaft moves along the X-axis guide rail back to the initial standby position, waiting for the next workpiece to enter the station. At the same time, the bolt hole distance data, tightening sequence data, torque and angle parameter data, and the real-time torque value recorded for each bolt involved in this tightening process are categorized according to the target machine model code D6-24 and uploaded to the backend database in JSON format via industrial Ethernet. A new record is added to the tightening history table in the database, containing information such as assembly time, station number, machine model code, actual torque and angle of each bolt, tightening result, and whether an alarm occurred. This data can be used by quality engineers for future process analysis, trend monitoring, or tracing of non-conforming products, thereby optimizing tightening parameters or providing early warning of potential problems.

[0111] The embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the present invention is not limited thereto. Various changes can be made within the scope of knowledge possessed by those skilled in the art without departing from the spirit of the present invention.

Claims

1. A method for automatically adjusting the pitch of the tightening shaft in an automatic cylinder head bolt tightening machine, characterized in that, include: Obtain the model instruction of the assembly station, wherein the model instruction is used to specify the target model of the engine to be assembled; according to the model instruction, obtain the model code corresponding to the target model from the background database, wherein the model code is used to uniquely identify the assembly specifications of the target model; Based on the machine model code, tightening data matching the machine model code is retrieved from the central process database. The tightening data includes bolt hole spacing data, tightening sequence data, and torque angle parameter data. Based on the bolt hole distance data, control the tightening shaft to move to the sleeve replacement station, and drive the sleeve replacement fixture to disassemble the current sleeve and replace it with a target sleeve that matches the bolt hole distance data. Based on the tightening sequence data and the torque angle parameter data, the tightening shaft is controlled to drive each servo motor to move the tightening head to the target position of each bolt corresponding to the bolt hole distance data, and the tightening shaft is locked after the movement is completed and a positioning signal is fed back. Based on the torque angle parameter data, the tightening shaft is controlled to descend to the target sleeve to fit the corresponding bolt, and the tightening operation is performed sequentially according to the tightening sequence data.

2. The automatic pitch-changing method for the tightening shaft of the automatic cylinder head bolt tightening machine according to claim 1, characterized in that, Based on the specified model instruction, retrieve the model code corresponding to the target model from the background database, including: When the engine enters the assembly station, the system receives the engine model instruction and performs a matching search in the background database according to the engine model instruction to obtain the engine model code corresponding to the target engine model. The engine model code includes the cylinder head structure identifier and bolt layout identifier of the target engine model.

3. The automatic pitch-changing method for the tightening shaft of the cylinder head bolt automatic tightening machine according to claim 2, characterized in that, Based on the machine model code, retrieve the tightening data matching the machine model code from the central process database, including: Based on the cylinder head structure identifier in the model code, obtain the bolt hole distance data corresponding to the cylinder head structure identifier from the central process database; Based on the bolt layout identifier in the model code, obtain the tightening sequence data corresponding to the bolt layout identifier from the central process database; Based on the cylinder head structure markings and the bolt layout markings, torque angle parameter data matching the target model are obtained from the central process database.

4. The automatic pitch-changing method for the tightening shaft of the cylinder head bolt automatic tightening machine according to claim 3, characterized in that, Based on the bolt hole spacing data, the tightening shaft is controlled to move to the sleeve replacement station, and the sleeve replacement fixture is driven to disassemble the current sleeve and replace it with a target sleeve that matches the bolt hole spacing data, including: The specification parameters of the target sleeve are determined based on the bolt hole spacing data, wherein the specification parameters include the sleeve inner diameter and the sleeve depth; Control the tightening shaft to move to the disassembly position of the sleeve changing fixture, and drive the sleeve changing fixture to remove the current sleeve from the tightening head; The robotic arm is controlled to place the disassembled sleeve replacement fixture onto the fixture rack and to pick up the fixture containing the target sleeve that matches the specified parameters. Install the target sleeve onto the tightening head, and confirm that the installation is in place according to the specifications.

5. The automatic pitch-changing method for the tightening shaft of an automatic cylinder head bolt tightening machine according to claim 4, characterized in that, Based on the tightening sequence data and the torque angle parameter data, the tightening shaft is controlled to drive each servo motor to move the tightening head to the target position of each bolt corresponding to the bolt hole distance data. After the movement is completed, the tightening shaft is locked and a positioning signal is fed back, including: Based on the coordinate information of each bolt in the bolt hole spacing data and the priority sorting of each bolt in the tightening sequence data, the movement path of the tightening head is generated. Each servo motor is controlled to drive the tightening head to move sequentially to the target position of each bolt according to the moving path. When moving to each target position of a bolt, the position is calibrated according to the coordinate information of the bolt in the bolt hole distance data. Once the tightening head moves to the target position of the last bolt, the tightening shaft is controlled to perform a locking action based on the locking torque parameter in the torque angle parameter data, and a positioning signal is generated.

6. The automatic pitch-changing method for the tightening shaft of an automatic cylinder head bolt tightening machine according to claim 5, characterized in that, Before controlling each servo motor to drive the tightening head to move sequentially to the target position of each bolt according to the said movement path, the method further includes: Based on the distance information between adjacent bolts in the bolt hole distance data, calculate the movement time of the tightening head between the target positions of adjacent bolts; Based on the tightening time parameters of each bolt in the torque angle parameter data, calculate the dwell time of the tightening head at the target position of each bolt; Based on the movement time and the dwell time, a motion control timing sequence for each servo motor is generated, wherein the motion control timing sequence is used to coordinate the movement and dwell actions of the tightening head.

7. The automatic pitch-changing method for the tightening shaft of an automatic cylinder head bolt tightening machine according to claim 6, characterized in that, Based on the torque angle parameter data, the tightening shaft is controlled to move downwards to insert the target sleeve into the corresponding bolt, and the tightening operation is performed sequentially according to the tightening sequence data, including: Based on the downward speed parameter in the torque angle parameter data, the tightening shaft is controlled to descend at a preset speed, wherein the preset speed is determined according to the tightening difficulty level of each bolt; When the target sleeve contacts the corresponding bolt, the tightening head is controlled to apply an initial torque according to the initial torque parameter in the torque angle parameter data; Based on the target torque and target angle values ​​of the current bolt in the tightening sequence data, the tightening head is controlled to complete the tightening of the current bolt according to the preset torque-angle curve; Once the current bolt is tightened, the tightening shaft is moved to the target position of the next bolt according to the priority of the next bolt in the tightening sequence data, and the tightening operation is repeated until all bolts are tightened.

8. The automatic pitch-changing method for the tightening shaft of an automatic cylinder head bolt tightening machine according to claim 7, characterized in that, After controlling the tightening shaft to move downwards according to the torque angle parameter data, inserting the target sleeve into the corresponding bolt, and performing the tightening operation sequentially according to the tightening sequence data, the method further includes: The real-time torque data of the target sleeve during the tightening operation is acquired, wherein the real-time torque data is collected by a torque sensor on the tightening head; The deviation value is obtained by comparing the real-time torque data with the target torque value in the torque angle parameter data; If the deviation value exceeds a preset threshold, the tightening shaft is controlled to stop the tightening operation of the current bolt, and a tightening abnormality alarm signal is generated.

9. The automatic pitch-changing method for the tightening shaft of an automatic cylinder head bolt tightening machine according to claim 8, characterized in that, After the deviation value exceeds a preset threshold, the method further includes stopping the tightening operation of the current bolt by controlling the tightening shaft and generating a tightening abnormality alarm signal. Based on the tightening sequence data, determine the next priority bolt for the current bolt; Control the tightening shaft to move to the target position of the next priority bolt, and perform the tightening operation of the next priority bolt according to the corresponding parameters in the torque angle parameter data; After all bolts have been tightened, a tightening quality report is generated based on the real-time torque data. The tightening quality report includes a comparison between the actual torque value and the target torque value of each bolt.

10. The automatic pitch-changing method for the tightening shaft of an automatic cylinder head bolt tightening machine according to claim 9, characterized in that, The method further includes: After all bolts are tightened, the tightening shaft is controlled to return to the initial position, and the bolt hole spacing data, tightening sequence data, torque angle parameter data, and real-time torque data during this tightening process are uploaded to the background database according to the model code. The background database is used to record the tightening history data of the target model.

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