A cleaning assembly for a wheel hub

Abstract

This invention discloses a cleaning production line and method for mass production of wheel hubs, belonging to the field of parts manufacturing technology. The invention provides a fully automated cleaning production line comprising a front conveyor line, a pre-cleaning conveyor line, a rear conveyor line, a post-processing module, and a PLC control system. The front conveyor line adopts a double-row roller structure, using first and second sets of photoelectric sensors to achieve two-stage deceleration and precise positioning of the wheel hubs. The pre-cleaning conveyor line uses a flipping mechanism to lift horizontal wheel hubs and flip them to a vertical position for high-pressure spray cleaning. The rear conveyor line receives the wheel hubs restored to a horizontal position and sequentially processes them through rinsing, pure water rinsing, and drying, coordinating the timing of each station and fault diagnosis. This invention achieves full automation, high-precision connection, and energy conservation and environmental protection in the wheel hub cleaning process, and is suitable for automated cleaning operations in the mass production of automotive wheel hubs.

Description

Technical Field

[0001] This invention belongs to the field of automotive parts manufacturing technology, specifically a cleaning production line and method for mass production of wheel hubs. Background Technology

[0002] In the field of mass production of wheel hubs, the pre-cleaning process after machining is a key step in removing oil, emulsion, aluminum chips and dust from the surface of the wheel hub. The quality of the cleaning directly affects the adhesion, appearance consistency and corrosion resistance of the subsequent coating process.

[0003] Currently, the industry mainly uses the following cleaning solutions, but all of them have significant technical defects: First, there is a structural contradiction between the degree of automation and the accuracy of transmission. To achieve efficient cleaning, suspended conveyor lines are often used to ensure that the wheel hubs enter the cleaning area vertically. However, this solution relies heavily on manual loading and unloading, which is labor-intensive, inefficient, and difficult to adapt to the pace of mass production. While robots can automate loading and unloading, the cyclical motion accuracy of the suspended chain (typically with a cumulative error of 5-10 mm) is difficult to match with the positioning requirements of the robot (usually within 1 mm), resulting in difficulties in product positioning, a high failure rate in grasping, and a serious imbalance between equipment investment and output benefits.

[0004] Secondly, the continuity of the cleaning process and the complexity of the control logic are significant challenges. While existing cleaning solutions (such as the single-tank lifting cleaning device disclosed in Chinese patent CN201933118U) can achieve lifting cleaning within a single tank, they are difficult to adapt to automated production lines. A complete cleaning line typically includes multiple stages such as pre-cleaning, rinsing, pure water rinsing, and drying. Achieving smooth, precise, and automated flow of wheel hubs between different workstations, as well as the time-series coordinated control of each workstation (such as spraying, ultrasonic cleaning, and drying), is a key bottleneck for improving overall efficiency. In existing technologies, each workstation is often controlled independently, lacking unified time-series coordination, resulting in poor inter-process connections and long idle waiting times.

[0005] Third, there are issues of cleaning quality control and resource waste. Traditional cleaning methods that use non-pure water for the final rinsing often leave water droplets (stains) on the wheel hub surface after drying due to the presence of calcium and magnesium ions in ordinary water. This affects the final appearance quality and can even lead to defects such as pinholes and fisheyes in subsequent painting. Furthermore, existing pure water rinsing devices mostly use continuous spraying, operating regardless of whether wheel hubs are passing by, resulting in significant waste of pure water and electricity. How to precisely control spraying and lifting actions based on the actual position of the wheel hub to achieve "on-demand operation" is a technical problem that the industry urgently needs to solve.

[0006] Therefore, there is an urgent need for an automated cleaning production line and its control method that can automatically rotate and transport wheel hubs, seamlessly connect with upstream and downstream processes, and be precise, reliable, energy-saving and environmentally friendly. Summary of the Invention

[0007] In view of the shortcomings of the existing technology, the purpose of this invention is to provide a cleaning production line and method for mass production of wheel hubs.

[0008] To achieve the above objectives, the present invention provides the following technical solution: a cleaning production line for mass production of wheel hubs, comprising: a front conveyor line (10) for conveying horizontally placed wheel hubs (50) to the cleaning station, wherein the front conveyor line (10) adopts a double-row roller structure and the double-row rollers form a first flip-plate clearance structure (100); a pre-cleaning conveyor line (20) connected to the front conveyor line (10), wherein a flip-plate mechanism (40) is provided on it for lifting the horizontal wheel hubs and flipping them to a vertical position for cleaning; a rear conveyor line (30) connected to the pre-cleaning conveyor line (20) for outputting the wheel hubs that have been cleaned and flipped back to a horizontal position, wherein a second flip-plate clearance structure (300) is provided on it; a post-processing module is arranged sequentially along the direction of the rear conveyor line (30), comprising at least a rinsing device, a pure water rinsing device (1) and a drying device; and a control system (PLC) comprising a controller, multiple position sensors and actuators.

[0009] The core of this invention lies in the control system, which achieves fully automatic and precise operation through the following innovative control logic: (1) Precise positioning and flip-plate control based on multi-level photoelectric sensors: A first set of photoelectric sensors (12) and a second set of photoelectric sensors (13) are sequentially set along the conveying direction on the front conveyor line (10), and a preset deceleration distance is maintained between the two sets of sensors. When the hub (50) passes the first set of photoelectric sensors (12), the control system controls the drive motor of the front conveyor line (10) to decelerate; when the hub (50) passes the second set of photoelectric sensors (13), the control system controls the drive motor of the front conveyor line (10) to stop completely, so that the hub is precisely positioned directly above the first flip-plate clearance structure (100); then, the control system starts the drive motor (23) of the pre-cleaning conveyor line (20), which drives the flip plate (40) to pass through the first flip-plate clearance structure (100) from bottom to top to smoothly lift the hub (50) and flip it to a vertical state.

[0010] (2) Composite motion control based on lifting and horizontal conveying: For workstations that use immersion or submersion cleaning methods (such as ultrasonic cleaning tanks), when the sensor detects that the hub is in place, the controller pauses the horizontal movement of the conveyor line; controls the lifting device to make the conveyor carrying the hub move vertically downward relative to the tank, so that the hub is completely immersed in the cleaning liquid; after the cleaning reaches the preset time, the controller controls the lifting device to move vertically upward; when the sensor detects that the hub is in place again, the horizontal conveying movement of the conveyor line is restarted.

[0011] (3) Pure water rinsing control based on collision triggering and timed reset: At the inlet of the pure water rinsing device (1), there is a collision rod (4) and a limit switch (5). Under normal circumstances, the water pump of the pure water rinsing device (1) is in standby mode; when the hub (7) on the conveyor line touches and pushes the collision rod (4), the collision rod (4) triggers the limit switch (5) which is electrically connected to the control system; after receiving the trigger signal, the control system immediately starts the water pump to spray; the control system has a built-in timing module, and when the water pump runs to the preset spraying time, it automatically shuts off the water pump and waits for the next trigger.

[0012] (4) Multi-module collaboration and fault alarm: The control system (PLC) is responsible for the timing logic control of the entire production line, coordinating the start and stop speeds of the front conveyor line (10), the pre-cleaning conveyor line (20), and the rear conveyor line (30), and controlling the collaborative work of the lifting device, water pump, fan, heater and other actuators; it has fault diagnosis and alarm functions: when a certain equipment fails or the sensor signal is abnormal, the control system triggers an audible and visual alarm and displays the fault location and fault code on the human-machine interface (HMI).

[0013] Compared with the prior art, the beneficial effects of the present invention are: First, it achieves full-process automation and high-precision docking. Through the two-stage deceleration-stop control logic of the first and second sets of photoelectric sensors, millimeter-level precise positioning of the wheel hub at the flipping station is achieved, solving the positioning problem when docking traditional conveyor lines with automated equipment. This enables the flipping mechanism to accurately and smoothly complete the "lift-flip" action without manual intervention, greatly improving production efficiency and reducing labor intensity.

[0014] Secondly, the reliability and adaptability of the control system have been improved. The control system adopts a modular and time-sequential logic design, with each workstation uniformly scheduled by a PLC, avoiding timing conflicts caused by independent control. The combined motion control of lifting and horizontal transmission ensures the smooth immersion and lifting of the wheel hub during the trough cleaning process, reducing the risk of collision damage.

[0015] Third, it significantly improves cleaning quality and appearance consistency. By introducing pure water rinsing before the drying process and achieving precise control over it, it effectively avoids residual mineral water stains on the wheel hub surface after drying, improves the product's appearance quality, provides a clean and residue-free substrate surface for subsequent coating processes, and reduces the coating defect rate.

[0016] Fourth, it achieves significant energy saving and consumption reduction. Through collision-triggered pure water spray control, an on-demand spraying mode is achieved: "spraying when the wheel hub arrives and stopping when the wheel hub leaves." Compared to continuous spraying, this saves over 60% of pure water consumption and reduces pump idling energy consumption. The coordinated control of each module prevents equipment idling, achieving energy-saving and environmentally friendly results.

[0017] Details of one or more embodiments of this application are set forth in the following drawings and description to make other features, objects and advantages of this application more readily apparent. The embodiments of this application will provide a detailed description and understanding of the application. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the structure of the hub-flipping pre-cleaning conveyor in an embodiment of the present invention, showing the spatial layout relationship of the front conveyor line (10), the pre-cleaning conveyor line (20), the flipping mechanism (40) and the rear conveyor line (30); Figure 2 for Figure 1 The top view of the device shows the installation positions of the first set of photoelectric sensors (12) and the second set of photoelectric sensors (13) on the front conveyor line (10), as well as the planar layout of the first flap clearance structure (100). Figure 3 This is a schematic diagram of the triggering structure of the pure water rinsing device in an embodiment of the present invention, showing the cooperation relationship between the collision rod (4), the rotating shaft (3), the support plate (2), the limit switch (5) and the soft material (6); Figure 4 The overall control flowchart of the control system of this invention shows the timing logic relationship between the feeding section, the turning and cleaning section, the tank cleaning section, the pure water rinsing section, the drying section and the unloading section.

[0019] In the diagram: 1. Pure water rinsing device; 2. Support plate; 3. Rotating shaft; 4. Collision rod; 5. Limit switch; 6. Soft material; 7. Wheel hub; 10. Front conveyor line; 12. First set of photoelectric sensors; 13. Second set of photoelectric sensors; 20. Pre-cleaning conveyor line; 22. Conveyor chain; 23. Drive motor; 30. Rear conveyor line; 40. Flipping mechanism; 41. Narrow section; 50. Wheel hub; 100. First flipping clearance structure; 300. Second flipping clearance structure. Detailed Implementation

[0020] 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.

[0021] Example 1: A hub-type flip-plate pre-cleaning conveyor device refer to Figure 1 and Figure 2 This embodiment provides a wheel hub flip-type pre-cleaning conveyor device, which is a core component of the wheel hub mass production cleaning line. It is mainly responsible for automatically flipping the horizontally placed wheel hubs to a vertical position and performing pre-cleaning treatment.

[0022] The front conveyor line (10) adopts a double-row roller structure with a central gap between the two rows of rollers, which forms the first flap clearance structure (100). The double-row rollers are driven by independent drive motors, and the conveying speed is controllable by frequency conversion speed regulation. A first set of photoelectric sensors (12) and a second set of photoelectric sensors (13) are installed sequentially along the conveying direction on the conveyor line. The distance between the two sets of sensors is set according to the conveyor line speed and deceleration requirements, usually 200~500mm. In this embodiment, the normal conveying speed V1 of the front conveyor line (10) is set to 12m / min, the low speed V2 is set to 3m / min, and the distance between the two sets of photoelectric sensors is set to 350mm. This distance can ensure that after the hub is decelerated by the first set of photoelectric sensors (12), it runs smoothly at low speed to the position of the second set of photoelectric sensors (13) and stops just in time.

[0023] Both the first group of photoelectric sensors (12) and the second group of photoelectric sensors (13) adopt through-beam photoelectric switches. The transmitting and receiving ends are respectively installed on both sides of the conveyor line, and the detection height is located at the center line of the wheel hub to ensure reliable detection of wheel hubs of various specifications. Both groups of sensors are electrically connected to the input module of the control system (PLC). The sensor signal adopts 24VDC digital input, and the response time is less than 2ms.

[0024] The pre-cleaning conveyor line (20) is driven by a motor (23) to make a circular motion of the conveyor chain (22), on which a pair of convex flaps (40) are fixed. The flaps (40) have a narrow part (41) and a wide part. The width of the narrow part (41) is smaller than the gap width of the first flap clearance structure (100) to ensure that it can pass through smoothly. In this embodiment, the gap width of the first flap clearance structure (100) is 120mm, and the width of the narrow part (41) of the flap is 80mm. The wide part of the flap is designed as an arc structure that matches the inner ring of the wheel hub, which can effectively support the wheel hub and keep it stable during the flipping process.

[0025] The downstream conveyor line (30) is arranged parallel to the pre-cleaning conveyor line (20) and is used to receive the horizontal hubs that have been flipped back from the pre-cleaning conveyor line (20) and transport them to the post-processing module. The downstream conveyor line (30) also adopts a double-row roller structure, with a second flap clearance structure (300) formed between the two rows of rollers. The gap width of the second flap clearance structure (100) is the same as or slightly larger than that of the first flap clearance structure (100) to ensure that the flap (40) can enter smoothly and place the hubs stably on the downstream conveyor line (30).

[0026] The workflow of a PLC control system is as follows: The first step is the feeding stage. The hub (50) is placed horizontally on the preceding conveyor line (10), with the rim facing down and the wheel surface facing up, and is conveyed forward by the double-row rollers. At this time, the control system controls the drive motor to run at the normal conveying speed V1.

[0027] The second step is the deceleration stage. When the hub (50) moves forward with the conveyor line, its edge first passes through the detection area of ​​the first set of photoelectric sensors (12). The photoelectric sensors (12) detect the presence of the hub and send a digital signal to the PLC. After receiving the signal, the PLC controls the drive motor of the preceding conveyor line (10) to decelerate from the normal conveying speed V1 to a low speed V2 through the frequency converter. This deceleration process adopts an S-curve deceleration method, and the deceleration time is 0.5 to 1 second to avoid hub slippage or inertial displacement caused by sudden stop.

[0028] The third step is the precise positioning and stopping stage. The hub (50) continues to move forward at a low speed V2. When it passes the second set of photoelectric sensors (13), the second set of photoelectric sensors (13) sends a signal to the PLC. After receiving the signal, the PLC immediately controls the drive motor to stop running. Since the distance from the installation position of the second set of photoelectric sensors (13) to the center line of the first flap clearance structure (100) has been precisely calibrated, and the inertia during low-speed operation is extremely small, the hub (50) can accurately stop directly above the first flap clearance structure (100), with a positioning accuracy of less than 2mm.

[0029] The fourth step is the flipping and lifting stage. After confirming that the preceding conveyor line (10) has stopped and the hub (50) has been accurately positioned, the PLC delays for 0.2 seconds to ensure system stability, and then starts the motor (23) of the pre-cleaning conveyor line (20). The motor (23) drives the conveyor chain (22) to operate, causing the flip plate (40) to move upward from the lower track of the pre-cleaning conveyor line (20). The narrow part (41) of the flip plate (40) first passes through the gap of the first flip plate clearance structure (100), and its wide part gradually supports the bottom of the inner ring of the hub (50). As the flip plate (40) continues to rise and move forward, the hub (50) is smoothly "lifted up" and moves in an arc around the flipping center. When the flip plate (40) moves to the upper track of the pre-cleaning conveyor line (20), the hub (50) has completed the flipping from the horizontal state to the vertical state. At this time, the wheel surface of the hub faces forward and the rim faces down, and it is supported by the flip plate (40) on the pre-cleaning conveyor line (20) for conveying.

[0030] Step 5, Pre-cleaning stage. The wheel hub (50), flipped to a vertical position, moves to the spray cleaning area along the pre-cleaning conveyor line (20). This area is equipped with two rows of high-pressure spray pipes, one above the other, aimed at the front and one below the back of the wheel hub, respectively. The PLC calculates the spraying time based on the conveyor line speed and the wheel hub diameter, and controls the high-pressure spray pump to rinse the wheel hub surface at a pressure of 0.5 MPa to remove residual oil, emulsion, and aluminum shavings from machining. The spraying time is 15-25 seconds, specifically set according to the degree of contamination of the wheel hub.

[0031] Step 6, the flipping and returning stage. After cleaning, the hub (50) continues to move along the circular track of the pre-cleaning conveyor line (20) with the flip plate (40). When the flip plate (40) moves to the rear end of the pre-cleaning conveyor line (20), it begins to move downward and enters the second flip plate clearance structure (300) of the subsequent conveyor line (30). As the flip plate (40) descends, the hub (50) gradually approaches the roller surface of the subsequent conveyor line (30). When the supporting surface of the flip plate (40) is lower than the roller surface, the hub (50) automatically stays on the subsequent conveyor line (30) due to gravity and returns to a horizontal state. At this time, the PLC controls the subsequent conveyor line (30) to start, conveying the hub backward to the post-processing module.

[0032] Throughout the flipping process, the movement trajectory of the flip plate (40) is a closed loop, and its movement speed is precisely matched with the speed of the preceding and following conveyor lines to ensure that the transfer of the hub between different workstations is smooth and without impact. The number of flip plates (40) is set according to the production cycle. In this embodiment, there are 6 pairs of flip plates, and the distance between two adjacent pairs of flip plates is 800mm, which can meet the production cycle requirement of 60 to 80 pieces per hour.

[0033] Example 2: A collision-triggered pure water rinsing control device refer to Figure 3This embodiment provides a collision-triggered pure water rinsing control device, which is installed on the downstream conveyor line (30) and is used to perform the final pure water rinsing treatment on the wheel hub after pre-cleaning and preliminary rinsing.

[0034] A pure water rinsing device (1) is installed on the downstream conveyor line (30). The pure water rinsing device (1) includes a pure water rinsing tank, a water pump, a spray pipe, a filtration system, and a piping system. The pure water rinsing tank is made of 304 stainless steel and has an effective volume of 200L. The tank is equipped with a level sensor and a conductivity sensor to monitor the level and quality of the pure water. When the level is lower than the set value or the conductivity exceeds the standard, the PLC automatically starts the water replenishment valve to replenish water or replace the pure water.

[0035] At the inlet of the pure water rinsing device (1), a collision rod (4) is installed via a support plate (2) and a rotating shaft (3). The support plate (2) is an L-shaped steel plate, which is fixed to the side of the frame of the pure water rinsing device (1) by bolts. The rotating shaft (3) is a stainless steel shaft, which is mounted on the support plate (2) via a bearing with a seat, and can rotate freely. The collision rod (4) is made of bakelite, which has good insulation, wear resistance and self-lubrication. The collision rod (4) has a mounting hole in the middle, which is fixed to the rotating shaft (3) by a set screw, and can rotate synchronously with the rotating shaft (3).

[0036] The lower end of the collision rod (4) is covered with a soft material (6). In this embodiment, a food-grade silicone sleeve with a thickness of 5 mm and a Shore A hardness of 40 is used. The silicone sleeve is fixed to the lower outer surface of the collision rod (4) by adhesive, which can effectively prevent the surface of the wheel hub from being scratched during contact. The natural downward position of the collision rod (4) is carefully adjusted so that the outer edge of its lower silicone sleeve is slightly lower than the highest point of the horizontal wheel hub (7) on the subsequent conveyor line (30), ensuring that the wheel hub (7) can reliably touch and push the collision rod (4) when it passes by.

[0037] A spring-loaded rocker switch (5) is positioned above the collision rod (4). The limit switch (5) is fixed to the top of the support plate (2) via a mounting bracket, with its rocker arm opposite to the upper end of the collision rod (4). In its natural state, a gap of 3-5 mm is maintained between the upper end of the collision rod (4) and the rocker arm of the limit switch (5) to prevent accidental triggering. The contact capacity of the limit switch (5) is AC220V / 5A, and it is electrically connected to the input module of the PLC.

[0038] The control system's workflow is as follows: Step 1, Standby mode. Under normal circumstances, when no wheel hub passes by, the water pump in the pure water rinsing device (1) is in standby mode and does not consume power, and the spray pipe does not spray water. At this time, the pure water rinsing device (1) maintains only extremely low standby power consumption (less than 10W), mainly used for signal monitoring of the PLC input module.

[0039] The second step is the triggering stage. When the downstream conveyor line (30) delivers the hub (7) to the inlet of the pure water rinsing device (1), the outer edge of the hub (7) first touches the soft material (6) at the lower end of the collision rod (4). As the hub (7) continues to move forward, the hub (7) pushes the lower end of the collision rod (4) to deflect in the direction of the conveyor line. Since the collision rod (4) is fixed on the rotating shaft (3), according to the lever principle, the upper end of the collision rod (4) swings in the opposite direction.

[0040] The third step is the signal generation stage. The upper end of the collision rod (4) swings and touches the lever of the limit switch (5), causing the contacts of the limit switch (5) to close. The limit switch (5) sends a continuous digital signal (high level) to the PLC. After the PLC's input module detects the signal, it confirms that the trigger is valid.

[0041] The fourth step is the spraying stage. After receiving the trigger signal from the limit switch (5), the PLC immediately controls the water pump in the pure water rinsing device (1) to start through the output module. The water pump delivers pure water from the pure water rinsing tank to the spray pipe through the main pipeline and branch pipelines, and sprays it from the fan-shaped nozzles of the spray pipe onto the surface of the wheel hub (7) that it passes through. The spraying pressure is set to 0.2MPa, the nozzle flow rate is 5L / min, and the spray coverage width is 400mm, which can completely cover the front surface of the wheel hub.

[0042] Step 5, continuous spraying stage. The timing module (timer) in the PLC starts timing when it receives the rising edge of the limit switch (5) signal. The timing time T is calculated based on the conveying speed V of the downstream conveyor line (30) and the effective length L of the rinsing zone. The calculation formula is: T=L / V+t, where L is the distance from the spray start position to the rinsing zone outlet, V is the conveying speed of the downstream conveyor line (30), and t is the safety margin.

[0043] In this embodiment, the conveying speed V of the downstream conveyor line (30) is 6 m / min (i.e., 100 mm / s), the effective length L of the rinsing zone is 1200 mm, and the safety margin t is set to 3 seconds. Therefore, the timing time T = 1200 / 100 + 3 = 15 seconds. This means that from the first trigger moment, the water pump will run continuously for 15 seconds to ensure that the hub and subsequent hubs passing through it can completely pass through the rinsing zone and receive sufficient pure water rinsing.

[0044] Step 6, shutdown and reset phase. When the PLC timer reaches the preset 15 seconds, the PLC automatically shuts off the water pump output signal, the water pump stops running, and the spraying stops. At the same time, the hub (7) has completely passed through the rinsing area, the collision rod (4) automatically returns to its natural drooping state under gravity, the contacts of the limit switch (5) open, and the signal returns to a low level. The system returns to standby mode, waiting for the next hub to arrive.

[0045] It should be noted that the sprayed water automatically flows back to the upstream cleaning or rinsing water tank and does not return to the pure water tank, in order to ensure that the water quality in the pure water tank always meets the process requirements (conductivity less than 10S / cm).

[0046] Compared to the traditional continuous spraying mode, the collision-triggered control in this embodiment has the following significant advantages: Based on a production cycle of 60 pieces per hour, each wheel hub takes approximately 12 seconds to pass through the rinsing zone. Therefore, the actual operating time of the water pump per hour is 60 × 15 = 900 seconds (i.e., 15 minutes), while in the traditional continuous spraying mode, the water pump needs to run continuously for 60 minutes. Thus, this embodiment can save 75% of the water pump's operating energy consumption and approximately 70% of pure water consumption, demonstrating significant energy-saving and consumption-reducing effects.

[0047] Furthermore, when the distance between the two hubs is small, the second hub can pass through within the spray cycle of the first hub. At this time, the limit switch (5) is triggered again, and the PLC keeps the water pump running continuously through logic judgment, so that there will be no interruption of spraying. When the distance between the hubs is large (greater than the spray cycle), the water pump automatically shuts off between the two triggers, realizing true "on-demand spraying".

[0048] Example 3: Overall Coordination Process of the Control System refer to Figure 4 This embodiment details the timing logic control process of the PLC as a central controller over the entire cleaning production line. The PLC communicates with sensors, drivers, and actuators at each workstation via an industrial fieldbus (in this embodiment, a Profibus-DP bus with a transmission rate of 1.5 Mbps) to achieve the following timing logic control: (a) Loading section control: The loading section is mainly composed of the front conveyor line (10). The PLC uses the first set of photoelectric sensors (12) and the second set of photoelectric sensors (13) to decelerate and precisely position the wheel hub to stop. The specific control logic has been described in detail in Embodiment 1. In addition, a third set of photoelectric sensors is provided at the entrance of the loading section to detect whether a wheel hub to be cleaned has entered. When no wheel hub is detected for 3 consecutive seconds, the PLC determines that it is a loading idle period and can control the front conveyor line (10) to enter a low-speed standby mode to reduce energy consumption.

[0049] (ii) Control of the Tilting and Cleaning Section: The tilting and cleaning section consists of a pre-cleaning conveyor line (20) and a high-pressure spray system. The PLC controls the motor (23) of the pre-cleaning conveyor line (20) to drive the tilting plate (40) to complete the "lift-tilt" action. In the pre-cleaning section, the PLC coordinates the start and stop of the high-pressure spray pump and sets the spray pressure (usually 0.3~0.8MPa) and spray time according to the hub material and the degree of oil contamination. Specifically, the PLC accurately determines the position of the tilting plate (40) based on the feedback signal from the encoder installed on the pre-cleaning conveyor line (20). When the tilting plate (40) reaches the spray area, the PLC starts the spray pump; when the tilting plate (40) leaves the spray area, the PLC stops the spray pump. For wheel hubs made of different materials (such as aluminum alloy wheel hubs and magnesium alloy wheel hubs), the PLC can retrieve the corresponding process parameter formulas: the spray pressure for aluminum alloy wheel hubs is set to 0.5MPa and the spray time is 20 seconds; the spray pressure for magnesium alloy wheel hubs is set to 0.3MPa and the spray time is 25 seconds (because magnesium alloys are more sensitive to corrosion, they require more thorough rinsing but lower pressure).

[0050] (III) Tank Cleaning Section Control: For the ultrasonic cleaning tank in the post-processing module, the PLC performs composite motion control of lifting and horizontal transmission. When the through-beam photoelectric sensor at the entrance of the ultrasonic cleaning tank above the downstream conveyor line (30) detects that the hub is in place, the PLC first pauses the horizontal movement of the downstream conveyor line (30). After a 0.5-second delay until the conveyor line has completely stopped, the PLC controls the servo motor of the lifting device to descend at a speed of 100 mm / s, so that the transport device (basket or pallet) carrying the hub descends vertically relative to the tank. During the descent, the PLC monitors the lifting position through limit switches and encoder feedback. When the hub is completely immersed in the cleaning fluid (immersion depth is 1.2 times the hub height to ensure complete immersion), the PLC stops the descent and starts the ultrasonic generator. The ultrasonic cleaning frequency is set to 28 kHz, the power density is 1.5 W / cm, and the cleaning time is set to 4 minutes. During the cleaning process, the PLC also controls the heater of the cleaning tank to maintain the cleaning fluid temperature at 50~60℃ to obtain the best cleaning effect. After the cleaning time reaches the preset time, the PLC first shuts off the ultrasonic generator and heater, delays for 5 seconds to allow the ultrasonic waves to attenuate, and then controls the lifting device to rise vertically at a speed of 80 mm / s. The rising speed is slightly lower than the falling speed to avoid violent shaking of the cleaning fluid. When the lifting device rises to a safe height (the bottom of the hub is 50 mm above the upper edge of the tank), the proximity switch installed at the upper limit position sends a signal to the PLC. After the PLC confirms, it restarts the horizontal conveying motion of the downstream conveyor line (30) to transport the hub to the next station.

[0051] (iv) Rinsing Section Control: The rinsing section consists of a general rinsing device. The PLC controls the water pump of the general rinsing device to perform preliminary rinsing on the wheel hubs and remove residual cleaning liquid from the surface. The general rinsing device adopts a continuous spraying method because the surface of the wheel hubs still has a small amount of cleaning liquid after ultrasonic cleaning, which needs to be thoroughly rinsed. The rinsing water adopts a recycling method, and is reused after impurities are removed by the filtration system. It is automatically replaced when the water quality drops to the set standard. The PLC calculates the residence time of each wheel hub in the rinsing zone based on the speed of the downstream conveyor line (30) and the length of the rinsing zone to ensure that the residence time is not less than 10 seconds. When the distance between two consecutive wheel hubs is detected to be greater than the set value, the PLC can temporarily shut down the rinsing pump to avoid water waste.

[0052] (V) Pure Water Rinse Section Control: The control logic of the pure water rinsing section has been described in detail in Embodiment 2. The PLC controls the pure water rinsing pump to work intermittently by receiving the signal from the limit switch (5) to achieve on-demand spraying. In this embodiment, the PLC also adds an intelligent judgment function: when it detects that the distance between continuously passing wheel hubs is less than a set threshold (such as 5 seconds), the PLC automatically extends the running time of the water pump to avoid water pump wear caused by frequent start-stop; when no wheel hub is detected to pass for 30 consecutive seconds, the PLC forcibly shuts down the water pump and outputs a prompt message to remind the operator to check whether there is any abnormality in the front-end process.

[0053] (vi) Drying section control: The drying section consists of a high-pressure blower, heater, air knife and temperature sensor. The PLC controls the start and stop of the high-pressure blower and heater according to the speed of the downstream conveyor line (30). A temperature sensor is installed at the inlet of the drying device. The PLC dynamically adjusts the hot air temperature according to the ambient temperature: when the ambient temperature is below 15℃, the hot air temperature is set to 75℃; when the ambient temperature is between 15 and 25℃, the hot air temperature is set to 70℃; when the ambient temperature is above 25℃, the hot air temperature is set to 65℃. This temperature range can ensure that the surface of the wheel hub is completely dry and there is no risk of thermal deformation (the thermal deformation temperature of aluminum alloy wheel hubs is usually higher than 150℃, so the set temperature has sufficient safety margin). The start of the drying section adopts predictive control: when the PLC detects that the wheel hub is about to enter the drying section (by obtaining the signal in advance through the upstream sensor), the blower and heater are started 3 seconds in advance to preheat, ensuring that the hot air is in a stable state when the wheel hub enters the drying section. The drying time is automatically adjusted according to the wheel size: 30 seconds for wheels under 16 inches, 40 seconds for wheels between 16 and 19 inches, and 50 seconds for wheels over 19 inches.

[0054] (vii) Unloading Section Control: Wheel hubs that have completed all processes are conveyed to the unloading position by the downstream conveyor line (30). A counting sensor is installed at the unloading position, and the PLC counter records the number of wheel hubs that have been cleaned. The counter increments by 1 for each wheel hub that is cleaned. The PLC uploads production data (including output, equipment operating status, fault information, etc.) to the host computer MES system via industrial Ethernet to realize real-time acquisition and analysis of production data. When the count reaches the preset batch quantity (e.g., 200 pieces), the PLC outputs a batch completion signal to prompt the operator to change the collection container or conduct quality inspection sampling. At the same time, the PLC automatically calculates and records the average cleaning time, pure water consumption, energy consumption, and other data of the batch, providing data support for production optimization.

[0055] (VIII) Fault Diagnosis and Alarm Control: The PLC possesses comprehensive fault diagnosis and alarm functions. When a fault occurs at any workstation, the PLC adopts different handling strategies based on the fault type: For minor faults (such as sensor signal flashing, temperature deviation, etc.), the PLC outputs a yellow warning message on the HMI interface, records the fault log, but does not stop the production line; the operator handles it at an appropriate time. For general faults (such as single water pump failure, conveyor speed deviation, etc.), the PLC outputs an orange alarm message, automatically activates backup equipment (such as the backup pump in a dual-pump system) or adjusts process parameters to maintain production, and simultaneously notifies maintenance personnel. For serious faults (such as main motor overload, encoder signal loss, safety door opening, etc.), the PLC immediately executes the emergency stop procedure: cuts off the main power output, stops all moving parts, shuts down all pumps and fans, outputs a red alarm message on the HMI interface and displays the fault location and fault code, and simultaneously triggers the audible and visual alarms. After an emergency stop, the PLC locks the start function; it can only be restarted by authorized personnel after troubleshooting and resetting. The PLC's fault diagnosis function is achieved by monitoring parameters such as the signal status of various sensors, motor current and temperature, and feedback signals from actuators. When a parameter exceeds the normal range or a signal malfunctions (such as signal loss, response timeout, or logic conflict), the PLC uses its built-in diagnostic program to determine the fault type and location. All fault information is timestamped and stored in the PLC's internal memory, which can record up to 500 recent fault records for easy post-event analysis and equipment maintenance.

[0056] Example 4: Compatibility handling for multiple wheel specifications In actual production, wheel hub batch cleaning lines need to be compatible with wheel hubs of various specifications (different diameters, widths, and weights). This embodiment describes the compatibility handling method of the cleaning line of the present invention for wheel hubs of multiple specifications.

[0057] (a) Hub Specification Identification: In the feeding section, a laser rangefinder sensor group is installed on the side of the preceding conveyor line (10) to automatically identify the diameter and width of the hub. When the hub passes through the sensor group, the PLC calculates the diameter D and width W of the hub based on the feedback data from multiple laser rangefinder sensors. The PLC compares the detected specification data with the preset specification database and automatically calls the corresponding process parameter formula. For example, for an aluminum alloy hub with a diameter of 18 inches (approximately 457 mm) and a width of 8 inches (approximately 203 mm), the PLC automatically calls the corresponding parameters: deceleration distance of 350 mm, spray pressure of 0.5 MPa, spray time of 22 seconds, pure water rinsing time of 16 seconds, and drying time of 40 seconds.

[0058] (ii) Adjustment of the position of the flip-plate mechanism: The spacing of the flip-plate mechanism (40) can be adjusted manually or electrically to accommodate wheel hubs of different diameters. For wheel hubs with a diameter of less than 16 inches, a flip-plate pair with a spacing of 700 mm is used; for wheel hubs with a diameter of 16 to 19 inches, a flip-plate pair with a spacing of 800 mm is used; for wheel hubs with a diameter of more than 19 inches, a flip-plate pair with a spacing of 900 mm is used. The flip-plate replacement adopts a quick replacement design and can be completed within 10 minutes, reducing downtime for model changeover.

[0059] (III) Sensitivity adjustment of photoelectric sensors: The sensitivity of the first group of photoelectric sensors (12) and the second group of photoelectric sensors (13) can be remotely adjusted by PLC. For dark-colored wheel hubs (such as black and gunmetal gray), the sensitivity of the sensors should be increased appropriately; for light-colored wheel hubs (such as silver and white), the sensitivity should be decreased appropriately to avoid false detection or missed detection.

[0060] (iv) Automatic adjustment of spray parameters: The nozzles of the high-pressure spray system are designed with adjustable angles. The PLC automatically adjusts the spray angle of the nozzles according to the wheel hub diameter to ensure that the spray water can cover the entire surface of the wheel hub. For large-diameter wheel hubs, the PLC increases the spray pressure and extends the spray time to ensure the cleaning effect.

[0061] (v) Automatic adjustment of pure water rinsing parameters: The PLC automatically calculates the spraying time of the pure water rinsing device based on the hub width. The calculation formula is: T=(D+W) / V+t, where D is the hub diameter, W is the effective width margin of the rinsing area, V is the conveyor linear speed, and t is the safety margin. For wider hubs, the spraying time is automatically extended to ensure that both sides of the hub receive sufficient pure water rinsing.

[0062] Example 5: Safety and Maintenance Design of a Cleaning Production Line This embodiment describes the design details of the cleaning production line of the present invention in terms of safety protection and daily maintenance.

[0063] (I) Mechanical Safety Design: The conveyor chain (22) of the flip mechanism (40) is equipped with a mechanical overload protection clutch. When the flip mechanism encounters abnormal resistance during movement (such as wheel hub jamming or foreign object entry), the clutch automatically slips, protecting the motor (23) and transmission mechanism from damage. At the same time, the PLC monitors the current of the motor (23). When the current exceeds 120% of the rated value for 2 seconds, the PLC determines it to be an overload fault, immediately stops the section of the conveyor line and alarms. Safety guardrails and safety doors are provided on both sides of each conveyor line. The safety doors are equipped with safety interlock switches. When the safety door is opened, the interlock switch sends a signal to the PLC, and the PLC immediately stops the movement of the conveyor line in that area to prevent personnel injury. The area cannot be started when the safety door is not closed and locked. The lifting device is equipped with upper and lower double limit protection: a safety limit switch is installed at each of the upper and lower limit positions. When the encoder or ordinary limit switch fails, the safety limit switch acts as the last line of protection, forcibly cutting off the power supply of the lifting motor.

[0064] (II) Electrical Safety Design: The power supply for the control system (PLC) adopts a dual-UPS uninterruptible power supply design. When the main power supply fails, the UPS automatically switches to the backup power supply to ensure uninterrupted power supply to the PLC and critical sensors, preventing production data loss and unexpected equipment shutdown. All electrical equipment meets IP54 protection requirements, and critical equipment such as water pumps and motors meet IP55 protection requirements. The control cabinet is equipped with a temperature and humidity control system to ensure that the PLC and frequency converter operate under suitable ambient temperature (0~40℃) and humidity (below 85%RH). The control system is equipped with lightning protection and electromagnetic compatibility (EMC) design. All signal cables are shielded cables, and power cables and signal cables are laid separately to avoid electromagnetic interference causing signal abnormalities.

[0065] (III) Routine Maintenance Design: The conveyor chain (22) of the flip-plate mechanism (40) adopts a maintenance-free self-lubricating chain, which should be visually inspected every 2000 hours of operation or 3 months (whichever comes first). The chain tensioning device is equipped with a scale indicator, which allows operators to judge the chain elongation. When the elongation exceeds 2%, the chain should be replaced. The soft material (6) at the lower end of the collision rod (4) is a consumable part, which should be inspected every 5000 hours of operation or 1 month. When the wear exceeds 2mm or damage occurs, the chain should be replaced. The replacement operation is simple and quick, and can be completed within 5 minutes without disassembling the entire collision rod. The transmitting and receiving windows of the photoelectric sensor should be cleaned with anhydrous ethanol once a month to ensure detection accuracy. The filter of the pure water rinsing device should be cleaned or replaced every two weeks, and the nozzle should be checked once a month to remove any possible blockages. The PLC control system has a built-in equipment running time statistics function, which automatically records the cumulative running time of each motor, pump, and fan. When the preset maintenance cycle is reached, maintenance reminder information is output on the HMI interface to remind maintenance personnel to perform preventive maintenance.

[0066] (iv) Cleaning Solution Management: The ultrasonic cleaning tank is equipped with automatic replenishment and concentration control functions for the cleaning solution. A concentration sensor is installed inside the cleaning tank to monitor the concentration of the cleaning solution in real time. When the concentration is lower than the set value, the PLC controls the replenishment pump to automatically replenish concentrated cleaning solution; when the concentration is higher than the set value, the PLC controls the water replenishment valve to replenish clean water. The cleaning solution replacement cycle is automatically calculated based on the degree of contamination and the cleaning volume. The PLC comprehensively judges the service life of the cleaning solution based on parameters such as conductivity, turbidity, and pH value, and outputs a prompt when replacement is needed.

[0067] The above embodiments merely illustrate several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

[0068] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A cleaning production line for mass production of wheel hubs, characterized in that, include: A front conveyor line (10) is used to transport horizontally placed wheel hubs (50) to the cleaning station. The front conveyor line (10) adopts a double-row roller structure, and the double-row rollers form a first flip-plate clearance structure (100). A pre-cleaning conveyor line (20) is connected to the front conveyor line (10). The pre-cleaning conveyor line (20) is provided with a flip-plate mechanism (40) for lifting the horizontal wheel hubs and flipping them to a vertical position for cleaning. A rear conveyor line (30) is connected to the pre-cleaning conveyor line (20) and is used to output the wheel hubs that have been cleaned and flipped back to a horizontal position. The rear conveyor line (30) is provided with a second flip-plate clearance structure (300). A post-processing module is arranged sequentially along the direction of the rear conveyor line (30) and includes at least a rinsing device, a pure water rinsing device (1), and a drying device. A control system is also provided. The system (PLC) includes a controller, multiple position sensors, and actuators; wherein, the front conveyor line (10) is provided with a first set of photoelectric sensors (12) and a second set of photoelectric sensors (13) in sequence along the conveying direction. The control system is configured to: when the hub (50) passes the first set of photoelectric sensors (12), control the drive motor of the front conveyor line (10) to decelerate; when the hub (50) passes the second set of photoelectric sensors (13), control the drive motor of the front conveyor line (10) to stop, so that the hub (50) is precisely positioned directly above the first flip-plate clearance structure (100); then start the drive motor (23) of the pre-cleaning conveyor line (20), drive the flip-plate mechanism (40) to pass through the first flip-plate clearance structure (100) from bottom to top to pick up the hub (50) and flip it to a vertical state.

2. The cleaning production line according to claim 1, characterized in that, The flipping mechanism (40) includes a pair of convex flipping plates, each having a narrow portion (41) and a wide portion. The width of the narrow portion (41) is less than the gap width of the first flipping clearance structure (100). The flipping plate (40) moves in a ring under the drive of the drive motor (23) and the conveyor chain (22).

3. The cleaning production line according to claim 1, characterized in that, The first group of photoelectric sensors (12) and the second group of photoelectric sensors (13) maintain a preset deceleration distance of 200~500mm.

4. The cleaning production line according to claim 1, characterized in that, The post-processing module also includes an ultrasonic cleaning tank, which is equipped with a lifting device. The control system is configured to: when the sensor detects that the hub is in position, control the lifting device to make the transport device carrying the hub move vertically downward relative to the tank, immersing the hub in the cleaning solution; after the cleaning reaches a preset time, control the lifting device to move vertically upward; when the sensor detects that the hub has risen to a safe height again, restart the horizontal conveying motion of the conveyor line.

5. The cleaning production line according to claim 1, characterized in that, The inlet of the pure water rinsing device (1) is provided with a collision rod (4) and a limit switch (5). The collision rod (4) is installed at the inlet end of the pure water rinsing device (1) through a rotating shaft (3) and a support plate (2). The lower end of the collision rod (4) is covered with a soft material (6). The control system is configured such that: under normal circumstances, the water pump of the pure water rinsing device (1) is in standby mode; when the hub (7) touches and pushes the collision rod (4), the collision rod (4) triggers the limit switch (5) which is electrically connected to the control system. After receiving the trigger signal, the control system starts the water pump to spray; when the water pump runs for the preset spraying time, the water pump is automatically turned off.

6. The cleaning production line according to claim 5, characterized in that, The preset spraying time T is determined based on the conveying speed V of the downstream conveyor line (30) and the effective length L of the rinsing zone. The calculation formula is: T=L / V+t, where t is a safety margin and the value range is 2~5 seconds.

7. The cleaning production line according to claim 1, characterized in that, The control system communicates with sensors, drivers, and actuators at each workstation via an industrial fieldbus, which includes Profibus, Modbus, or EtherCAT bus. The control system has fault diagnosis and alarm functions. When equipment malfunctions or sensor signals are abnormal, it triggers an audible and visual alarm and displays the fault location and fault code on the human-machine interface.

8. A cleaning method for mass production of wheel hubs, characterized in that, The method employs the cleaning production line as described in any one of claims 1-7. Includes the following steps: S1: Loading and conveying step, the horizontally placed wheel hub (50) is placed on the front conveyor line (10) for conveying; S2: Deceleration and positioning step, when the wheel hub (50) passes the first set of photoelectric sensors (12), the control system controls the front conveyor line (10) to decelerate; when the wheel hub (50) passes the second set of photoelectric sensors (13), the control system controls the front conveyor line (10) to stop, so that the wheel hub (50) is precisely positioned above the first flip-plate clearance structure (100); S3: Turning and cleaning step, the control system starts the pre-cleaning conveyor line (20), which drives the flip-plate mechanism (40) to pass through the first flip-plate clearance structure (100) from bottom to top to pick up the wheel hub (50) and turn it to a vertical position, and performs high-pressure spray cleaning on the pre-cleaning conveyor line (20); S4: Post-processing step, after cleaning, the wheel hub is transported to the downstream conveyor line (30) by the flipping mechanism (40). The flipping mechanism (40) moves downward into the second flipping clearance structure (300). The wheel hub (50) automatically stays on the downstream conveyor line (30) due to gravity and returns to a horizontal state. Then it goes through rinsing, pure water rinsing and drying in sequence. S5: Unloading step, the wheel hub that has completed all processes is transported to the unloading position by the downstream conveyor line (30).

9. The cleaning method according to claim 8, characterized in that, The pure water rinsing process in step S4 specifically includes: when the hub (7) moves to the inlet of the pure water rinsing device (1) along the conveyor line, it touches the collision rod (4), the collision rod (4) rotates around the shaft (3) and triggers the limit switch (5) above; the limit switch (5) sends a signal to the control system, and the control system starts the water pump of the pure water rinsing device (1) to spray; the timing module in the control system starts timing, and automatically shuts off the water pump when the preset spraying time is reached, waiting for the next trigger.

10. The cleaning method according to claim 8, characterized in that, The spray pressure of the high-pressure spray cleaning in step S3 is 0.3~0.8MPa; the drying process in step S4 uses hot air generated by a high-pressure blower and a heater for drying, the hot air temperature is 60~80℃, and the drying time is dynamically adjusted according to the ambient temperature.

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