A control and monitoring method for assembling an automotive decelerator
By introducing a PLC control system into the reducer assembly process, combined with a touch screen and an electric setpoint wrench, the problems of non-standard screw tightening and missing data were solved, realizing intelligent and traceable reducer assembly, and improving assembly quality and efficiency.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- SHANDONG PENGXIANG AUTOMOBILE
- Filing Date
- 2026-02-12
- Publication Date
- 2026-06-19
AI Technical Summary
In the current assembly process of automotive reducers, the screw tightening lacks visual guidance and error prevention control, resulting in non-standard tightening, difficulty in adapting to the assembly of multiple models, and lack of electronic records and data traceability, which affects the assembly quality and efficiency.
Using a PLC as the control core, combined with a touch screen, electric fixed-value wrench and workpiece detection sensor, it realizes visual operation, error prevention control and data recording. Through PLC initialization, workpiece identification, tightening parameter calling and error prevention release logic, it ensures the standardization of screw tightening and data integrity.
It has enabled intelligent and traceable assembly of the reducer, improved assembly quality and efficiency, reduced the difficulty of manual operation, and enhanced the flexibility of the production line and the versatility of the equipment.
Smart Images
Figure CN122239610A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of automotive manufacturing and assembly automation technology, and in particular to a control and monitoring method for automotive reducer assembly. Background Technology
[0002] When assembling automotive reducers, screws are mainly tightened manually using handheld electric wrenches. This method cannot ensure the accuracy of screw torque. If screws are tightened using a single-function tightening tool monitoring system, there is a lack of visual guidance on tightening methods and sequences, as well as production line-linked error prevention control. Similarly, it cannot ensure that workers follow process specifications.
[0003] Different models of reducers have different assembly requirements. Incorrect tightening sequence and method may affect the stress distribution during assembly, leading to the risk of oil leakage in the reducer assembly. In addition, the entire reducer assembly process relies heavily on manual experience and conscientiousness, which has a high operational threshold. The tightening process of the workpiece lacks electronic recording, making it difficult to trace quality problems and resulting in a lack of data analysis.
[0004] In summary, there is a need for an intelligent tightening monitoring system that can provide visual guidance, prevent omissions and errors, and record data. This system would facilitate improved assembly quality of reducer assembly, reduce the manual difficulty of reducer assembly, and help with rapid location and data analysis for quality traceability. Summary of the Invention
[0005] In view of the shortcomings of the existing technology, the present invention aims to provide a control and monitoring method for automotive reducer assembly. It is a visually guided and production line-linked automotive reducer assembly tightening monitoring system that can effectively solve a series of assembly problems such as missing screws, non-standard tightening, inability to adapt to multi-model assembly, inability to digitally track, and inability to trace the execution of process standards.
[0006] The technical solution provided by this invention is: a control and monitoring method for assembling an automotive reducer, characterized in that it includes a PLC as the control core, and further includes: a touch screen for visual operation and providing a human-machine interface and assembly monitoring interface; an electric fixed-value wrench for performing tightening operations and providing feedback of the end signal; a workpiece detection sensor for detecting whether the workpiece has reached the assembly station; and a main control circuit for providing reasonable and safe power to all components; including the following steps: Step 1: PLC initialization, loading pre-stored tightening parameter formulas and prompts, and monitoring screen data corresponding to different product models; Step 2: After the workpiece arrives at the assembly station, receive the product model selection instruction input by the user through the human-machine interface; Step 3: According to the product model selection instruction, call the tightening parameter formula corresponding to the selected product model to the electric fixed value wrench, and switch to the corresponding assembly monitoring interface, where the visual status of the corresponding position is updated. Step 4: Determine whether all screws on the current workpiece have been tightened to the required position; and determine whether it should proceed to the next workstation.
[0007] Furthermore, it also includes error prevention control steps. When the PLC determines that the screw tightening operation of all the specified positions of the current workpiece has not been completed, it will trigger an alarm and output a control signal to prevent the production line from releasing the workpiece to the next station.
[0008] Furthermore, it also includes a data statistics step, recording the start and end times of tightening for each workpiece, the product model, and calculating the daily completion quantity according to the model. Furthermore, it obtains the system time by executing pre-stored macro instructions, formats it, and then associates the tightening completion time with the workpiece information before storing it in the LW register area.
[0009] The beneficial effects of this invention are: 1. Intelligent assembly process and tightening control: Through the complete method of "selecting model - calling process - visual guidance - process monitoring - error prevention and release", the assembly production line that relies on human experience and ability is transformed into a controllable and standardized one; 2. Improve assembly quality and traceability: The built-in anti-mis-tightening logic and data recording function in the method fundamentally avoid human error and generate a complete production data chain, which facilitates quality traceability and lean production analysis; 3. Enhance production line flexibility: By calling "assembly process" and "display screen", the same hardware system can be quickly adapted to the production of different products, improving equipment versatility and assembly efficiency. Attached Figure Description
[0010] Figure 1 This is a hardware architecture diagram of the present invention; Figure 2 This is a flowchart illustrating the overall implementation of the present invention. Detailed Implementation
[0011] To more clearly illustrate the technical solution of the present invention, the present invention will be described in detail below with reference to the accompanying drawings. This embodiment aims to fully explain the specific implementation of the automotive reducer assembly tightening monitoring method and system. The present invention will be described in detail below with reference to the accompanying drawings and as can be achieved by those skilled in the art.
[0012] The hardware system architecture of this invention, such as Figure 1As shown, its core is to build an integrated system with a PLC as the decision-maker and an industrial touch screen (HMI) as the central hub for the coordinated control of an electric fixed-value wrench. Based on a Mitsubishi FX3C-16MR / ES-A programmable logic controller (PLC), the PLC is compiled to carry analog input / output points, connecting to a workpiece positioning sensor to directly acquire tightening torque and detect whether the workpiece has reached the designated position and time. The PLC itself has built-in analog I / O points, which can directly acquire the torque analog signal (such as 0-10V or 4-20mA) output by the electric fixed-value wrench without the need for external expansion modules, ensuring the closed-loop integration of "control command output" and "torque signal monitoring". Through the powerful CC-Link network function, it can be expanded to a maximum of 256 points, with sufficient flexible upgrade interfaces reserved. The built-in data logging function can cache key data such as the timing and status of the tightening process in the machine first, and then upload them to the HMI at regular intervals via communication. Key interfaces are introduced in Table 1.
[0013] As an intelligent operating terminal, the touch screen is used for visual operation and provides a human-machine interface and assembly monitoring interface. It communicates with the PLC via RS485 / 232 serial port. After visual operation, it can display the tightening process guidance screen, display the selected product model and call the corresponding tightening parameters and other data. The touch screen has a high resolution of 1024×600 and the front panel reaches the NEMA4 / IP65 protection level. It is the hardware foundation for storing multiple sets of product tightening parameter formulas and smoothly running complex background macro instructions. The position, number and status color of screws in its graphical guide interface are clearly distinguishable, which can effectively resist oil, dust and liquid splashes in the assembly site and ensure the environmental robustness of the interactive medium. HMI and PLC exchange data through specific registers, which are described in Table 2.
[0014] The electric setpoint wrench is connected to the PLC to perform tightening operations and provide feedback of the end signal. By parsing its communication protocol or I / O characteristics, the PLC's Y0 output signal is converted into start and stop commands that the wrench can recognize, while the "tightening complete" signal (X1) fed back by the wrench is collected. This transforms it from an isolated tool into an intelligent execution terminal controlled by a central system. In addition, the workpiece detection sensor is used to detect whether the workpiece has arrived at the assembly station. The signal is connected to the X0 input point of the PLC and is the starting trigger condition for the entire automation control process. The main control circuit system has a total power supply of AC220V, which is responsible for the introduction, distribution, on / off control and short circuit / overload protection of the equipment's total power supply.
[0015] A method for controlling and monitoring the assembly of an automotive reducer, such as Figure 2It includes the following steps: Step 1: After the system starts, perform PLC initialization (S201) and load the pre-stored tightening parameter formulas and prompts, as well as monitoring screen data corresponding to different product models. Step 2: The PLC detects whether the workpiece is in position using the workpiece detection sensor (S202); if it is in position, it proceeds to S203 and receives the product model selection command input by the user through the human-machine interface. Step 3: The operator selects the product model on the main interface of the touch screen (S203); the PLC selects the product model (e.g., M1 corresponds to model 440, M2 corresponds to model 400) and calls up the corresponding tightening parameters and monitoring screen (S204). Step four: The system enters the core tightening monitoring cycle (S205), and the detailed steps are as follows: 1) S301: Set the initial tightening point position number i=1; 2) S302: Monitor the tightening completion signal at the i-th position; 3) S303: Determine whether the i-th position has been tightened; if so, update the icon of the i-th position on the touch screen interface to the completed state (turns green) (S304), and execute S305; if not, continue monitoring. 4) S305: Determine if all positions (e.g., i≥21) have been tightened; if not all are completed, then i=i+1 (S306), and return to S302 to monitor the next position; if all are completed, then execute S307. 5) S307: Record the completion timestamp and workpiece information for this assembly; 6) S308: Output permission signal (Y10 is on); 7) S309: If the system receives a clearance request during the loop (i.e., before all loops are completed), an alarm will be triggered immediately (S310), and the clearance will remain blocked. After all tightening is completed, the system records the data and allows release (S206), the workpiece flows out, and the process ends (S207).
[0016] The specific implementation process of the present invention is further explained as follows: (1) Initialization and workpiece identification (corresponding to process S201-S204) After the system is powered on, the PLC and HMI complete a communication self-test; the HMI loads all pre-stored product formulas and screen resources; when the workpiece detection sensor signal X0 changes from OFF to ON, the PLC's internal auxiliary relay M100 (workpiece position indicator) is set; the rising edge of M100 triggers the HMI to pop up the product selection main interface; the operator's selection action (such as clicking the "440 type" button) will trigger the HMI to execute two core operations: "screen switching" and "data writing". The human-machine division of labor code is introduced in Table 3. Table 3. Introduction to Human-Machine Division of Labor Codes Vbnet: HMI button "Type 440" press event script =SetData(1, "HMI", "D0") / / Writes product code "1" into the PLC's D0 register. =SetDevice( "M1", 1) / / Sets the M1 coil of the PLC, notifying the PLC to call the recipe. (2) Linkage between recipe and visuals After receiving the product model code (D0 value) and the call instruction (M1 rising edge), the PLC executes two parallel and related instructions within a single scan cycle to achieve intelligent synchronization and hardware-software locking between hardware parameters (wrench) and software interface (screen). (3) Visual guidance and sequential tightening monitoring (corresponding processes S301-S306) The screw positions are represented by graphical icons; the PLC internally maintains a tightening sequence (e.g., from position 1 to position 21) and uses a data register D100 as the current tightening position pointer; initially, all icons are grayed out, and D100 has a value of 1; when the PLC receives the "tightening complete" signal (rising edge of X1) from the electric fixed-value wrench, it executes a 4-step operation: 1) Use the INC instruction to increment the completion count counter D101 by 1; 2) Use the MOV instruction to transfer the current value of D100 to a status array D200 (starting address), and mark the position to complete; 3) Through communication, the HMI is instructed to dynamically update the corresponding icon on the interface to green; 4) Use the INC instruction to increment the position pointer D100 by 1, pointing it to the next position to be tightened; (4) Error prevention control and release logic (corresponding to process S305, S307-S310) In each scan cycle, the PLC executes a comparison instruction CMP to determine whether the current completed quantity D101 is equal to the preset total quantity D102 (e.g., 21). If they are equal (all completed): the PLC drives M200 (release permission flag) to be set, thereby enabling output point Y10. The Y10 signal can control the green light to illuminate or directly unlock the blocking cylinder of the production line, allowing the workpiece to flow into the next station; if they are not equal and the system detects a release request, corresponding to input X2: the PLC will immediately set M300 (alarm flag), enabling output point Y11, driving the audible and visual alarm, and displaying a prominent alarm screen covering the entire screen on the HMI, while strictly keeping Y10 in the off state; (5) In-depth implementation and interpretation of data recording and macro instructions (corresponding process S206) To achieve refined data traceability, a dedicated periodically triggered macro instruction was written in the HMI for the acquisition, formatting, and storage of high-precision timestamps. The macro instruction code follows a data pipeline of acquisition → conversion → normalization → assembly: First, the raw hour, minute, and second values are accurately obtained from the HMI system registers; then, each value is converted into an independent string, and a zero-value verification mechanism is introduced, dynamically padding zeros before single digits based on conditional judgment to ensure a consistent time unit format; finally, a multi-level string concatenation engine structurally assembles the processed time units and separators according to the international standard format "HH:MM:SS". This eliminates the risks of memory overflow and logical errors caused by segmented conversion, manual zero padding, and string concatenation; the generated string is written to a designated register, providing accurate timestamps for subsequent binding with product data and storage of historical records.
[0017] After trial use on the production line, the final system reduced the skill and experience requirements for operators, provided fast and reliable tightening guidance, and allowed for timely tracking of the assembly status of any reducer assembly.
[0018] The above description is merely illustrative of the principles and performance of the present invention and does not represent the entirety of the invention. People can obtain other embodiments based on this embodiment without creative effort, and these embodiments all fall within the protection scope of the present invention.
Claims
1. A method for controlling and monitoring the assembly of an automotive reducer, characterized in that, The system includes a PLC as the control core, a touchscreen for visual operation and to provide a human-machine interface and assembly monitoring interface; an electric setpoint wrench for performing tightening operations and providing a feedback end signal; a workpiece detection sensor for detecting whether the workpiece has reached the assembly station; and a main control circuit for providing reasonable and safe power to all components. The system includes the following steps: Step 1: PLC initialization, loading pre-stored tightening parameter formulas and prompts, and monitoring screen data corresponding to different product models; Step 2: After the workpiece arrives at the assembly station, receive the product model selection instruction input by the user through the human-machine interface; Step 3: According to the product model selection instruction, call the tightening parameter formula corresponding to the selected product model to the electric fixed value wrench, and switch to the corresponding assembly monitoring interface, where the visual status of the corresponding position is updated. Step 4: Determine whether all screws on the current workpiece have been tightened to the required position; and determine whether it should proceed to the next workstation.
2. The control and monitoring method for an automotive reducer assembly according to claim 1, characterized in that, It also includes error prevention control steps. When the PLC determines that the screw tightening operation of all the specified positions of the current workpiece has not been completed, it will trigger an alarm and output a control signal to prevent the production line from releasing the workpiece to the next station.
3. The control and monitoring method for an automotive reducer assembly according to claim 1, characterized in that, It also includes a data statistics step, which records the start and end time of tightening each workpiece, the product model, and counts the daily completed quantity according to the model.
4. The control and monitoring method for an automotive reducer assembly according to claim 1, characterized in that, It also obtains the system time by executing pre-stored macro instructions, and after formatting, associates the tightening completion time with the workpiece information and stores it in the LW register area.