Dishwasher and method for detecting a malfunction of a spray system thereof

Abstract

The application discloses a kind of dish washer and its spray system fault detection method.Dish washer includes spray arm, rotating shaft, shaft seat and water distribution valve, permanent magnet is installed on rotating shaft, electromagnetic induction unit is installed on shaft seat.Detection method includes: during the operation of dish washer, the induction signal output by electromagnetic induction unit is continuously monitored;If induction signal meets the set rule, it is determined that no fault occurs;If induction signal does not meet the set rule or disappears, it is determined that a fault occurs.Further, dish washer can also include photoelectric detection device consisting of light emitting unit, light receiving unit and light transmission channel on rotating shaft, through the comprehensive judgment of two kinds of detection signals, interference signals can be filtered out and short-term faults that can be self-eliminated can be identified.The application can effectively detect and distinguish different faults such as spray arm locked-rotor, water distribution valve clogging and spray hole clogging, and has the advantages of simple structure, low cost and strong anti-interference capability.

Description

Technical Field

[0001] This invention belongs to the field of dishwasher technology, specifically, it relates to a method for detecting faults in a dishwasher and its spray system. Background Technology

[0002] The dishwasher pumps washing water from the bottom cup into the spray system via a wash pump. The spray system typically includes a water distribution valve and multiple spray arms (e.g., upper, middle, and lower layers). The water distribution valve switches between different water paths, allowing washing water to spray from different spray arms according to a preset washing cycle. Each spray arm has multiple spray holes, which are angled relative to the arm's axis. This angle allows water to flow from different angles, improving the washing effect.

[0003] During long-term use of a dishwasher, the spray system is prone to the following malfunctions: (1) the spray arms become blocked due to foreign objects, causing water to spray only from a fixed direction and angle, making it impossible to achieve multi-angle rinsing; (2) the internal channels of the water distribution valve are blocked by foreign objects, causing abnormal water circuit switching, and some spray arms cannot obtain sufficient water; (3) the spray holes on the spray arms are blocked by food residue or scale, causing changes in the reaction force on the spray arms and affecting their normal rotation trajectory. Any of the above malfunctions will significantly reduce the cleaning effect of the dishwasher, and may result in stains remaining on the dishes after the washing program ends, requiring users to wash them again, wasting electricity and water resources.

[0004] To address the aforementioned issues, some improvements have been proposed in existing technologies. For example, a magnetic block is installed on the spray arm, and a magnetic field detection circuit is placed at a corresponding location inside the dishwasher. When the spray arm rotates, the magnetic block moves with it, and the magnetic field detection circuit outputs a corresponding electrical signal. When an abnormal electrical signal is detected, a malfunction in the spray system is detected, and the dishwasher can issue an alarm. However, this technical solution has the following problems: the spray arm is usually far from the sensing circuit on the dishwasher's inner wall. To ensure the effectiveness of the detection signal, a strong magnetic block is required. However, a strong magnetic field may interfere with the normal operation of other electromagnetic components inside the dishwasher (such as the water inlet solenoid valve and drain pump motor), affecting the overall reliability of the machine. When the dishwasher has multiple spray arms, if each spray arm is equipped with a magnetic block, the magnetic fields generated by each magnetic block are prone to mutual interference, leading to disordered detection signals and making it difficult to accurately determine which spray arm is malfunctioning. Furthermore, the overall detection circuit is complex, resulting in high hardware costs. Summary of the Invention

[0005] To address the aforementioned technical problems, this invention proposes a method for detecting faults in the spray system of a dishwasher and a dishwasher in general, enabling intelligent self-diagnosis and accurate location of faults in the spray system.

[0006] The present invention is implemented using the following technical solutions: A method for fault detection of a dishwasher spray system is proposed. The dishwasher includes a washing chamber and a spray system disposed in the washing chamber. The spray system includes a plurality of spray arms and a water distribution valve responsible for switching different water paths to different spray arms. Each spray arm is equipped with a rotating shaft for driving the spray arm to rotate and a bearing for supporting the rotating shaft. The dishwasher further includes a first fault detection device; the first fault detection device includes a permanent magnet and an electromagnetic induction unit, wherein the permanent magnet is mounted on a rotating shaft, and the electromagnetic induction unit is mounted on a shaft seat; the detection method includes: During dishwasher operation, the sensing signal output by the electromagnetic induction unit is continuously monitored; If the sensing signal matches the set rules, it is determined that the sprinkler system is not malfunctioning. If the sensing signal does not conform to the set rules or disappears, it is determined that the sprinkler system has malfunctioned.

[0007] Compared with existing technologies, the advantages and positive effects of this invention are as follows: In the dishwasher spray system fault detection method proposed in this invention, a permanent magnet is installed on the rotating shaft of each spray arm, and an electromagnetic induction unit is installed on the shaft seat. Utilizing the physical principle that the permanent magnet rotates synchronously with the rotating shaft when the spray arm rotates, and the magnetic lines of force periodically cut the electromagnetic induction unit, the mechanical rotation state of the spray arm is directly converted into an electrical signal that can be recognized by the controller in real time. When the spray arm rotates normally, a regularly changing magnetic flux is generated between the permanent magnet and the electromagnetic induction unit, and the induced signal exhibits regular periodic characteristics. When the spray arm stalls, the rotating shaft stops rotating, the permanent magnet stops, the magnetic lines of force no longer cut the electromagnetic induction unit, and the induced signal disappears. When the water distribution valve is completely blocked, preventing water from entering the spray arm, the spray arm also stops rotating, and the induced signal disappears. When the spray holes are blocked or the water distribution valve is not completely blocked, causing abnormal water flow, the induced signal is abnormal. This solution eliminates the need for complex motion conversion mechanisms. It achieves fault self-sensing solely through the inherent rotation of the spray arms, resulting in a fast detection response. Furthermore, when there are a large number of spray arms, the permanent magnets on each shaft are effectively shielded by the dishwasher's metal casing, preventing magnetic field interference between them and ensuring the accuracy of the detection.

[0008] In some embodiments of the present invention, the dishwasher further includes a second fault detection device; the second fault detection device includes a light emitting unit and a light receiving unit arranged on a shaft seat, and the two are arranged opposite to each other; and a light-transmitting channel is opened at the same height position as the light emitting unit and the light receiving unit on the rotating shaft; the detection method further includes: During dishwasher operation, the photoelectric conversion signal output by the light receiving unit is continuously monitored; If the photoelectric conversion signal is a pulse signal with a set rule, then the sprinkler system is determined to be without fault. If the photoelectric conversion signal is a pulse signal that does not conform to the set rules or disappears, it is determined that the sprinkler system has malfunctioned.

[0009] In this embodiment, a light emitting unit and a light receiving unit are arranged opposite each other on the shaft, and a light-transmitting channel is opened at the same height as the two on the rotating shaft to construct a photoelectric detection channel. When the spray arm rotates normally, the rotating shaft rotates accordingly, and the light-transmitting channel periodically rotates to the position aligned with the light emitting unit and the light receiving unit. The light signal intermittently passes through the light-transmitting channel and is received by the light receiving unit, thereby outputting a regular pulse electrical signal. The frequency of this pulse signal is directly related to the rotation speed of the spray arm and can accurately reflect the real-time rotation state of the spray arm. When the spray arm stalls or the water distribution valve is completely blocked, causing the rotating shaft to stop, the light-transmitting channel is stationary. The light receiving unit either continuously receives the light signal (if it stops at the light-transmitting position) or continuously does not receive the light signal (if it stops at the non-light-transmitting position). In both cases, it no longer outputs a pulse signal with periodic characteristics. When the water distribution valve is partially blocked or the spray hole is partially blocked, causing the rotation speed of the spray arm to change, the rotation speed of the light-transmitting channel changes, and the frequency of the pulse signal changes accordingly, deviating from the set rule. The working principles of photoelectric detection and electromagnetic induction detection are completely different. They are independent of each other and redundant, which can effectively avoid misjudgments that may occur due to environmental factors (such as temperature changes affecting electromagnetic properties, water mist affecting the optical path, etc.) caused by a single detection method.

[0010] In some embodiments of the present invention, the detection method further includes: If the sensing signal and the pulse signal continuously reflect the same fault information within a preset time period, then the fault is confirmed to have occurred. If the fault information reflected by the sensing signal and the pulse signal within a preset time period is inconsistent, it is determined to be an interference fault.

[0011] In this embodiment, the induction signal output by the electromagnetic induction unit and the pulse signal output by the photoelectric receiving unit are comprehensively compared and judged, utilizing the difference in the physical principles of the two detection methods to achieve anti-interference. In the actual working environment of a dishwasher, improper placement of tableware may cause the spray arm to be briefly stuck and then recover on its own, or fluctuations in water flow may cause instantaneous fluctuations in the spray arm speed. At this time, a single detection signal may show a brief abnormality, but the device has not actually experienced a continuous malfunction. By setting a preset time period, the two detection signals are required to continuously reflect consistent fault information in the time dimension before a fault is confirmed, which can effectively filter out the above-mentioned transient interference. At the same time, since the two detection methods share the same rotating shaft as the signal source, if the fault information reflected by the two is inconsistent (for example, the electromagnetic induction signal is abnormal while the photoelectric signal is normal), it indicates that at least one detection device has been interfered with by external factors rather than the spray system itself malfunctioning. This judgment logic significantly reduces the probability of false alarms, so that the dishwasher only triggers the subsequent processing flow when a continuous and substantial fault actually occurs, improving the reliability of the system and the user experience.

[0012] In some embodiments of the present invention, the detection method further includes: If the sensing signal and / or the pulse signal briefly show fault information within a preset time period, it is determined to be a self-eliminating transient fault.

[0013] In this embodiment, the identification and filtering of self-eliminating temporary faults are achieved by detecting the transient appearance of inductive signals and / or pulse signals. During the actual operation of the dishwasher, the spray arm may momentarily jam due to food residue or small foreign objects. However, with the impact of water flow or the inertia of the spray arm itself, this jamming state may spontaneously dissipate within a very short time, and the spray arm will then resume normal rotation. The signal abnormality at this time is a self-recoverable transient phenomenon, which does not require triggering a fault alarm or interrupting the washing process. By setting a preset time threshold, a real fault is only determined when the signal abnormality state continues to exceed the threshold. Signal abnormalities that disappear spontaneously within the threshold time are determined to be self-eliminating transient faults, and no response action is triggered. This solution avoids frequent false alarms or accidental interruptions to the washing process due to non-substantial jamming of the dishwasher, ensuring both the sensitivity of fault detection and the continuity of the washing process and the smoothness of the user experience.

[0014] In some embodiments of the present invention, if the sensing signal does not conform to the set rules, it is determined that the sprinkler system has malfunctioned, specifically including: If the sensing signal disappears, it is determined that a type of fault has occurred in the sprinkler system; the type of fault is that the sprinkler arm is blocked or the water distribution valve is completely blocked, resulting in the complete misalignment of the water distribution plate. If the sensing signal exists but does not conform to the set rules, it is determined that the sprinkler system has a type II fault; the type II fault is that the water distribution valve is blocked, causing partial misalignment of the water distribution plate or blockage of the sprinkler holes.

[0015] In this embodiment, by finely identifying different abnormal forms of the sensing signal, the system achieves differentiated diagnosis of fault types in different parts of the sprinkler system. When the sprinkler arm is completely jammed and blocked, the shaft stops rotating completely, the permanent magnet no longer cuts the magnetic lines of force, and the sensing signal disappears completely. When the water distribution valve causes the water distribution plate to be completely misaligned and completely blocked, water cannot flow into the sprinkler arm at all, the sprinkler arm also stops rotating, and the sensing signal also disappears completely—the two exhibit the same signal characteristics and are classified as the same type of fault. However, when the water distribution plate of the water distribution valve is partially misaligned, resulting in only partial blockage, some water still flows into the sprinkler arm. Although the sprinkler arm can rotate, the speed is significantly lower than normal. The sensing signal still exists, but its waveform frequency or amplitude deviates from the set rules. When individual sprinkler holes on the sprinkler arm are blocked, the balance of the reaction force on the sprinkler arm is disrupted, and the rotation trajectory and speed become abnormal. This is also manifested as the presence of a sensing signal but with an abnormal waveform—the two are classified as the second type of fault. By classifying the sensor signals into two states, "disappeared" and "existing but abnormal," and associating each with different causes of failure, repair personnel can quickly locate the faulty part based on the fault type information output by the dishwasher during manual inspection. For relatively easy-to-handle faults such as clogged spray nozzles, the spray arm can be cleaned directly. For more serious faults such as completely blocked water distribution valves or stalled spray arms, targeted disassembly and repair can be performed, significantly shortening the troubleshooting and repair time.

[0016] The present invention also proposes a dishwasher, comprising: Washing chamber; The spray system configured in the washing chamber includes several spray arms and a water distribution valve responsible for switching different water paths to different spray arms; wherein, each spray arm is equipped with a rotating shaft for driving the spray arm to rotate and a bearing for supporting the rotating shaft. The first fault detection device includes a permanent magnet and an electromagnetic induction unit; wherein the permanent magnet is mounted on a rotating shaft and the electromagnetic induction unit is mounted on a shaft seat. The controller, connected to the electromagnetic induction unit, is configured to: During dishwasher operation, the sensing signal output by the electromagnetic induction unit is continuously monitored; If the sensing signal matches the set rules, it is determined that the sprinkler system is not malfunctioning. If the sensing signal does not conform to the set rules or disappears, it is determined that the sprinkler system has malfunctioned.

[0017] Compared with existing technologies, the advantages and positive effects of this invention are as follows: The dishwasher provided by this invention, which includes the aforementioned detection device, installs permanent magnets on the rotating shafts of each spray arm and electromagnetic induction units on the corresponding shaft seats, and connects the electromagnetic induction units to the controller signal. This allows the dishwasher to acquire real-time rotational status information of each spray arm during normal washing. The controller determines whether the spray system has malfunctioned based on whether the sensing signals conform to set rules. When the signals conform to the set rules, it indicates that the spray arms are rotating normally at the expected speed; when the signals do not conform to the set rules or disappear, a malfunction is determined. This dishwasher does not rely on users to check the cleanliness of the dishes after washing to detect abnormalities in the spray system. Instead, it detects malfunctions in real time during the washing process and can take timely countermeasures, avoiding the continuation of a full washing cycle when the spray system has malfunctioned. This saves water resources, electricity, and user time, and improves the intelligence level of the dishwasher and user satisfaction.

[0018] In some embodiments of the present invention, the dishwasher further includes: The second fault detection device includes a light emitting unit and a light receiving unit arranged on the bearing, and the two are arranged opposite to each other. A light-transmitting channel is provided at the same height as the light emitting unit and the light receiving unit, located on the rotating shaft. The controller is also configured to: During dishwasher operation, the photoelectric conversion signal output by the light receiving unit is continuously monitored; If the photoelectric conversion signal is a pulse signal with a set rule, then the sprinkler system is determined to be without fault. If the photoelectric conversion signal is a pulse signal that does not conform to the set rules or disappears, it is determined that the sprinkler system has malfunctioned.

[0019] The dishwasher provided by this invention further integrates a photoelectric detection device. A light emitting unit and a light receiving unit are arranged opposite each other on the shaft seat, and a light-transmitting channel is opened at the corresponding position on the rotating shaft, forming a second detection link independent of electromagnetic induction detection. During dishwasher operation, the controller continuously monitors the photoelectric conversion signal output by the light receiving unit, verifying the rotation state of the spray arm by determining whether the signal is a pulse signal according to a set rule. Electromagnetic induction detection and photoelectric detection are based on two completely different physical principles: magnetic field change and light path continuity. Both signals originate from the same mechanical rotation of the spray arm shaft, but they are independent and uncoupled in signal conversion and transmission paths. This redundant detection architecture allows the other detection device to independently perform fault detection even when one detection device experiences performance degradation or failure due to water mist condensation, dirt adhesion, or component aging, significantly improving the fault tolerance and long-term operational reliability of the dishwasher's fault detection system.

[0020] In some embodiments of the present invention, the control is further configured to: If the sensing signal and the pulse signal continuously reflect the same fault information within a preset time period, then the fault is confirmed to have occurred. If the fault information reflected by the sensing signal and the pulse signal within a preset time period is inconsistent, it is determined to be an interference fault.

[0021] In the dishwasher provided by this invention, the controller is further configured to verify the consistency of the sensing signal and the pulse signal within a preset time period. A fault is confirmed only when both signals consistently reflect consistent fault information; otherwise, it is determined to be an interference fault. Because the electromagnetic induction unit and the light receiving unit are installed in different positions—the former inside the bearing and the latter above—they face different interference sources: the electromagnetic induction unit is mainly affected by temperature changes and magnetic field environment, while the light receiving unit is mainly affected by water mist, lighting conditions, and dirt obstruction. When the dishwasher experiences momentary signal jitter in a single detection device due to vibration or water flow impact, the other detection device is likely unaffected. In this case, the fault information reflected by the two signals is inconsistent, and the controller determines it as interference without triggering fault confirmation. This judgment logic effectively overcomes the technical challenge of a single sensor being susceptible to environmental interference and false alarms in the complex and humid environment inside the dishwasher, enabling the dishwasher to maintain accurate fault judgment capabilities even in harsh working environments.

[0022] In some embodiments of the present invention, the control is further configured to: If the sensing signal and / or the pulse signal briefly show fault information within a preset time period, it is determined to be a self-eliminating transient fault.

[0023] In the dishwasher provided by this invention, the controller is further configured to identify abnormal characteristics of transiently occurring sensing signals and / or pulse signals within a preset time period, and to determine them as self-eliminating transient faults without responding. During the dishwasher washing process, the spray arm may sometimes experience a brief jam due to being momentarily blocked by large tableware (such as soup bowls, baby bottles, etc.), but this obstruction is quickly resolved by the spray arm's own rotational inertia or the force of the water flow; or small food residue may be briefly stuck in the gap between the rotating shafts and then washed away by the water flow, which are also temporary phenomena that can recover on their own. By setting a time window, the controller identifies abnormal signals with a duration shorter than the window as self-eliminating faults that do not require intervention, avoiding frequent interruptions of the washing process or unnecessary alarm prompts due to the aforementioned non-substantive faults. This ensures washing efficiency and avoids user inconvenience and after-sales complaints caused by frequent false alarms.

[0024] In some embodiments of the present invention, the controller is configured to, when it determines that a fault has occurred in the sprinkler system: If the sensing signal disappears, it is determined that a type of fault has occurred in the sprinkler system; the type of fault is that the sprinkler arm is blocked or the water distribution valve is completely blocked, resulting in the complete misalignment of the water distribution plate. If the sensing signal exists but does not conform to the set rules, it is determined that the sprinkler system has a type II fault; the type II fault is that the water distribution valve is blocked, causing partial misalignment of the water distribution plate or blockage of the sprinkler holes.

[0025] In the dishwasher provided by this invention, when the controller judges the fault of the sensing signal, it further distinguishes the specific fault type based on the abnormal pattern of the sensing signal and outputs corresponding diagnostic information. Specifically, when the sensing signal completely disappears, the controller determines it as a Class I fault. This fault may be caused by mechanical blockage due to the spray arm being jammed by a foreign object, or it may be caused by complete blockage of the water distribution valve, resulting in a complete interruption of water flow. Although the causes of the two faults are different, both are manifested by the spray arm completely stopping and unable to recover on its own, requiring manual intervention. When the sensing signal exists but its waveform does not conform to the set rules, the controller determines it as a Class II fault. This fault may be caused by partial blockage of the water distribution valve, resulting in insufficient water supply and thus affecting the rotation speed, or it may be caused by blockage of the spray holes, resulting in abnormal reaction force and thus affecting the uniformity of rotation. By outputting a clear fault type code to the user or maintenance personnel, the dishwasher can guide subsequent fault self-clearing or manual repair strategies. For Class II faults caused by blockage of the spray holes, it can usually be cleared by rinsing with high-temperature water. For Class I or Class II faults caused by blockage of the water distribution valve, manual disassembly and cleaning are required. This fault classification and diagnosis function enables the dishwasher to have intelligent fault prediction and graded processing capabilities, improving fault handling efficiency.

[0026] Other features and advantages of the present invention will become clearer after reading the following detailed description of the embodiments of the present invention in conjunction with the accompanying drawings. Attached Figure Description

[0027] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0028] Figure 1 This is a schematic diagram of the steps in the first embodiment of the dishwasher spray system fault detection method proposed in this invention; Figure 2 This is a schematic diagram of the first fault detection device for the dishwasher spray system proposed in this invention; Figure 3 This is a schematic diagram of the second fault detection device for the dishwasher spray system proposed in this invention; Figure 4This is a schematic diagram of the steps in the second embodiment of the dishwasher spray system fault detection method proposed in this invention. Detailed Implementation

[0029] 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.

[0030] The dishwasher provided by this invention includes a washing chamber and a spray system disposed within the washing chamber. The spray system includes several spray arms and a water distribution valve. The water distribution valve is used to switch different water paths according to a preset washing control process, causing water pumped by the washing pump to be sprayed from different spray arms in a predetermined sequence. The number of spray arms can be configured according to the specific model of the dishwasher and washing requirements; for example, it can be set to one, two, or more. A specific embodiment of this invention is illustrated using a dishwasher with upper, middle, and lower three-layer spray arms as an example.

[0031] Each spray arm is equipped with a rotating shaft 1 and a bearing 2, such as Figure 2 As shown, the rotating shaft 1 drives the spray arm to rotate, and the bearing seat 2 supports the rotating shaft 1. One end of the rotating shaft 1 is fixedly connected to the spray arm, and the other end is rotatably mounted in the bearing seat 2. The bearing seat 2 is fixedly mounted on the washing chamber wall or internal support of the dishwasher. The spray arm has several spray holes, and the opening direction of these spray holes has a predetermined tilt angle relative to the axis of the spray arm. When water flows out from the spray holes, it generates a reaction torque on the spray arm, pushing the spray arm to rotate around the rotating shaft 1, thereby realizing multi-angle spray rinsing.

[0032] The dishwasher also includes a first fault detection device, such as Figure 2 As shown, the first fault detection device includes a permanent magnet 3 and an electromagnetic induction unit 4. The permanent magnet 3 is fixedly mounted on the rotating shaft 2, and the electromagnetic induction unit 4 is fixedly mounted on the shaft seat 2. The mounting position of the electromagnetic induction unit 4 corresponds to the position of the permanent magnet 3, so that when the rotating shaft 1 rotates, the permanent magnet 3 rotates synchronously with the rotating shaft 2, and the magnetic lines of force generated by the permanent magnet 2 can periodically cut the electromagnetic induction unit 4. The electromagnetic induction unit 4 can be a component that can convert changes in magnetic field into electrical signals, such as a Hall sensor, a magnetoresistive sensor, or an electromagnetic induction coil. A Hall sensor is preferred because it has advantages such as small size, fast response speed, and low cost.

[0033] Based on the above, the dishwasher spray system fault detection method proposed in this invention is executed by a controller, which is signal-connected to the electromagnetic induction unit 4, such as... Figure 1 As shown, follow these steps to detect faults in the sprinkler system: S1: During dishwasher operation, continuously monitor the sensing signal output by the electromagnetic induction unit.

[0034] The controller can use the dishwasher's original main control chip, or a dedicated detection and control chip can be set up separately; both are within the protection scope of this invention.

[0035] During the dishwasher's startup and washing cycle, the washing pump pumps water from the water cup at the bottom of the washing chamber into the spray system, and the water distribution valve switches the water flow to different spray arms according to a preset sequence. After the water enters the spray arm, it is sprayed out from the spray nozzles, and the reaction force pushes the spray arm and the rotating shaft to rotate.

[0036] During the rotation of the spray arm, the permanent magnet 3 mounted on the rotating shaft 1 rotates synchronously with the rotating shaft 1, and the magnetic field generated by the permanent magnet 3 also changes periodically in space. Since the electromagnetic induction unit 4 is fixedly mounted on the shaft seat 2 and its position is fixed, the magnetic lines of force generated by the rotating permanent magnet 3 continuously cut the electromagnetic induction unit 4. The electromagnetic induction unit 4 generates an alternating induced electromotive force according to Faraday's principle of electromagnetic induction, that is, it outputs in the form of an induced electrical signal.

[0037] The controller continuously monitors the sensing signal output by the electromagnetic induction unit 4 during dishwasher operation. This sensing signal is a periodic alternating electrical signal, the frequency of which is proportional to the rotational speed of the shaft 1, and its amplitude is related to the magnetic field strength and rotational speed of the permanent magnet 3.

[0038] S2: Determine whether the sensing signal conforms to the set rules.

[0039] The controller compares the received sensing signal with preset setting rules, which may be preset voltage amplitude range, frequency range or waveform characteristic parameters.

[0040] S3: If the sensing signal meets the set rules, it is determined that the sprinkler system has not malfunctioned.

[0041] When the spray system is working normally, the spray arm rotates smoothly at the designed speed. The frequency, amplitude and waveform of the sensing signal are all within the preset normal range. At this time, the controller judges that the sensing signal meets the set rules, and then judges that the spray system has not malfunctioned and the washing program is running normally.

[0042] S4: If the sensing signal does not conform to the set rules or disappears, it is determined that the sprinkler system has malfunctioned.

[0043] Conversely, when the sprinkler system malfunctions, for example, if the sprinkler arm is jammed by a foreign object, causing it to stall, the rotating shaft 1 stops rotating, the permanent magnet 3 stops, the magnetic lines of force no longer cut the electromagnetic induction unit 4, the electromagnetic induction unit 4 cannot generate alternating induced electromotive force, and the induction signal disappears. Another example is if the water distribution valve becomes completely blocked, preventing water from entering the sprinkler arm, causing the sprinkler arm to stop rotating due to lack of driving force, and the induction signal also disappears. Yet another example is when the sprinkler orifice becomes blocked, the reaction torque on the sprinkler arm changes, and its rotational speed deviates from the design value. In this case, although the induction signal still exists, its frequency corresponding to the speed change or its waveform characteristics deviates from the set rules.

[0044] When the controller detects that the sensing signal does not conform to the set rules or disappears, it determines that the sprinkler system has malfunctioned.

[0045] Furthermore, the controller classifies faults based on the abnormal patterns of the sensing signals: if the sensing signal disappears, it is determined that a Class I fault has occurred in the sprinkler system, which corresponds to a stalled sprinkler arm or a completely blocked water distribution valve causing complete misalignment of the water distribution plate; if the sensing signal exists but its waveform characteristics, such as frequency, amplitude, and duty cycle, do not conform to the set rules, it is determined that a Class II fault has occurred in the sprinkler system, which corresponds to a partial blockage of the water distribution valve causing partial misalignment of the water distribution plate or a blockage of the sprinkler holes on the sprinkler arm.

[0046] In a preferred embodiment of the present invention, the dishwasher is further provided with a second fault detection device, which operates based on the photoelectric detection principle. Figure 3 As shown, the second fault detection device includes a light emitting unit 5 and a light receiving unit 6, which are arranged opposite each other at the same height on the bearing 2. The light emitting unit 5 can be a light-emitting diode (LED) or a laser diode to emit a detection beam; the light receiving unit 6 can be a photodiode, phototransistor, or photoresistor to receive the light signal emitted by the light emitting unit 5 and convert it into an electrical signal.

[0047] At the same height as the light emitting unit 5 and the light receiving unit 6, a light-transmitting channel 7 is provided on the rotating shaft 1. This light-transmitting channel 7 extends radially through the shaft 1, and its axial direction is perpendicular to the axis of rotation of the shaft 1. When the rotating shaft 1 rotates to a specific angle, the light-transmitting channel 7 aligns with the optical path between the light emitting unit 5 and the light receiving unit 6, and the detection beam emitted by the light emitting unit 5 passes through the light-transmitting channel 7 to reach the light receiving unit 6. When the rotating shaft 1 rotates to other angles, the solid part of the rotating shaft 1 blocks the optical path, and the light receiving unit 6 cannot receive the light signal. Therefore, under normal continuous rotation of the spray arm, the photoelectric conversion signal output by the light receiving unit 6 is a series of regular pulse signals. Each pulse corresponds to one event of the light-transmitting channel 79 aligning with the optical path, and the frequency of the pulse is proportional to the rotational speed of the rotating shaft 1.

[0048] The controller is connected to the light receiving unit 6 and continuously monitors the photoelectric conversion signal output by the light receiving unit 6 during dishwasher operation. If the photoelectric conversion signal is a pulse signal with preset rules, that is, the characteristics of the pulse frequency, amplitude, duty cycle and other features meet the preset normal operating parameter range, the controller determines that the spray system is not faulty; if the photoelectric conversion signal does not meet the pulse signal characteristics of the preset rules or the signal disappears, the controller determines that the spray system is faulty.

[0049] In a preferred embodiment of the present invention, the controller simultaneously receives the induction signal output by the electromagnetic induction unit 4 and the photoelectric conversion signal, i.e., the pulse signal output by the light receiving unit 6, and compares and judges the two signals in a comprehensive manner to improve the accuracy of fault detection and anti-interference capability.

[0050] Because electromagnetic induction detection and photoelectric detection are based on two completely different physical principles—the former based on changes in magnetic fields and the latter on the continuity of light paths—their respective sources of interference differ. For example, electromagnetic induction detection may be affected by stray magnetic fields generated by other electromagnetic components inside the dishwasher, such as motors and solenoid valves; photoelectric detection may be affected by reduced light transmittance caused by water mist condensing on the surface of the light emitting unit 5 or the light receiving unit 6 within the washing chamber. Therefore, signal anomalies in either detection method during operation may not originate from mechanical failures of the spray arm itself, but rather from interference from the aforementioned environmental factors.

[0051] To overcome this problem, the controller performs a comprehensive judgment on the two detection signals within a preset time period. Specifically, for example... Figure 4 As shown, the controller sets a preset time period T (e.g., T = 5 seconds or 10 seconds, which can be adjusted according to actual needs), and continuously collects and records the status of two detection signals during this time period. If, within this preset time period, both the sensing signal and the pulse signal continuously reflect consistent fault information—for example, both signals exhibit abnormalities with consistent abnormal characteristics—the controller confirms that a fault has indeed occurred. Conversely, if, within this preset time period, the fault information reflected by the sensing signal and the pulse signal is inconsistent—for example, the sensing signal is abnormal while the pulse signal is normal, or vice versa—the controller determines it to be an interference fault, does not trigger subsequent fault handling procedures, and the washing program continues to operate normally.

[0052] The above judgment logic makes full use of the independence and differences in the physical principles of the two detection methods. Only when the two signals jointly confirm the existence of the fault from different dimensions will a fault be confirmed, which effectively avoids misjudgment caused by interference from environmental factors due to a single sensor.

[0053] In another preferred embodiment of the invention, the controller is also configured to identify self-eliminating transient malfunctions. During the actual washing process of the dishwasher, the spray arm may experience transient rotational abnormalities for the following reasons: for example, large tableware such as soup bowls or baby bottles may be displaced by the water flow during spraying, temporarily blocking the rotation path of the spray arm, but the tableware is subsequently washed away by the continuous water flow, and the obstruction is removed; or, small pieces of food residue or bone fragments may briefly become stuck in the gap between the rotating shaft 1 and the bearing 2, but with the rotational inertia of the rotating shaft 1 or the scouring effect of the water flow, the residue is quickly crushed or washed away, and the stuck state is released. In the above cases, the abnormal rotation of the spray arm is transient and self-recoverable, without triggering a fault alarm or interrupting the washing process.

[0054] To address the above situation, the controller sets a preset time threshold t, for example, t = 2 seconds or 3 seconds. When an abnormality is detected in the sensing signal and / or pulse signal, it is not immediately identified as a fault, but a timer is started. If the abnormal signal disappears and returns to normal within the preset time threshold t, the controller determines it as a self-eliminating transient fault and does not trigger any subsequent response action; the washing program continues to operate normally. Only when the duration of the abnormal signal exceeds the preset time threshold t will the controller recognize it as a persistent fault and trigger the subsequent fault handling process.

[0055] In this embodiment of the invention, when the controller confirms that the sprinkler system has experienced a persistent fault, the following fault handling procedure is executed: S51: The controller pauses the currently running washing process. To prevent the sprinkler system from continuing to operate when it is malfunctioning, which would result in dishes not being washed properly and thus wasting water, electricity, and time.

[0056] S52: The controller initiates a fault self-clearing process.

[0057] Specifically, the self-clearing process includes, but is not limited to, the following: The controller activates the heating wire or heating tube in the washing pump to heat the water in the washing chamber to a preset high temperature, such as 70°C to 80°C. The high-temperature water has a stronger dissolving and decomposing ability, capable of dissolving and decomposing grease and protein blockages attached to the internal channels of the water distribution valve 2 or the spray nozzles of the spray arm. Simultaneously, the controller increases the speed of the washing pump, giving the water flow higher pressure and velocity. The enhanced water flow impact force flushes away the blockages softened and decomposed by the high temperature, restoring the spray system to normal operation.

[0058] Preferably, the heating and speed-up operations in step S52 can be performed individually or simultaneously. For grease-based blockages, heating alone can dissolve them; for fibrous or granular blockages, increasing the water flow rate alone can flush them away; for stubborn blockages, simultaneous heating and speed-up can achieve the best removal effect.

[0059] S53: After the fault self-clearing process has run for a preset time, the controller will perform fault detection again.

[0060] That is, repeat the detection and judgment steps described in the above embodiments to verify whether the fault has been cleared.

[0061] If the fault has been cleared after verification in step S53, i.e. the sensing signal and / or pulse signal have returned to normal, the controller will control the dishwasher to resume the suspended washing process and continue to complete the remaining washing, rinsing and drying programs.

[0062] If the fault is not cleared after verification in step S53, i.e., the sensing signal and / or pulse signal remain abnormal, the controller determines that the fault is a stubborn fault that cannot be eliminated through the self-cleaning process. For example, the spray arm may be mechanically blocked due to a large hard foreign object, or the water distribution valve may be completely blocked by hard particles. In this case, the controller will no longer attempt self-cleaning but will instead issue a fault alarm signal. Alarm methods include, but are not limited to: displaying fault codes and / or fault text information on the dishwasher's UI display interface, emitting a fault alarm sound through a buzzer or speaker, and pushing fault notification messages to the user's mobile terminal via the wireless communication module, prompting the user to perform manual inspection and repair in a timely manner.

[0063] In this invention, the positions of the first fault detection device (i.e., the permanent magnet 3 and the electromagnetic induction unit 4) and the second fault detection device (i.e., the light emitting unit 5, the light receiving unit 6, and the light-transmitting channel 7) on the spray arm shaft 1 have a specific correspondence. Specifically, during the rotation of the spray arm, the position that triggers the electromagnetic induction unit 4 to generate a change in the induced signal is the same as the position that triggers the light receiving unit 6 to generate a change in the photoelectric conversion signal.

[0064] This positional correspondence can be achieved as follows: the installation angle of the permanent magnet 3 and the opening angle of the light-transmitting channel 7 are kept consistent in the circumferential direction of the rotating shaft 1, that is, the center line of the magnetic pole of the permanent magnet 3 and the central axis of the light-transmitting channel 7 are located in the same radial plane of the rotating shaft 1. When the rotating shaft 1 rotates to a certain angle, the light-transmitting channel 7 is aligned with the optical path between the light emitting unit 5 and the light receiving unit 6, and the light receiving unit 6 outputs a high-level or low-level signal; at the same time, the magnetic pole of the permanent magnet 3 is exactly at an angle position opposite to the electromagnetic induction unit 4, and the electromagnetic induction unit 4 simultaneously outputs the corresponding peak or valley value of the induced signal. When the rotating shaft 1 rotates 180°, the light-transmitting channel 7 is completely deviated from the optical path, and the light receiving unit 6 outputs a signal of the opposite level; the other magnetic pole of the permanent magnet 3 is also at an angle position opposite to the electromagnetic induction unit 4, and the electromagnetic induction unit 4 outputs a peak or valley value of the induced signal of the opposite polarity.

[0065] By setting the corresponding positions as described above, the two detection signals are triggered synchronously in time. The controller can more accurately align and compare the two signals in time, which helps to further improve the accuracy of the comprehensive judgment. At the same time, since the two detection methods share the same trigger signal, when the spray arm speed changes, the frequency changes of the two signals occur synchronously. The controller can verify the reliability of the detection results by comparing the consistency of the frequency changes of the two signals.

[0066] For dishwashers with multiple spray arms, this invention can configure one or more sets of first fault detection devices and / or second fault detection devices for each spray arm. Since the rotating shafts and bearings of each spray arm are located at different positions within the dishwasher's washing chamber, with sufficient space between them, and since dishwashers are typically metal shells that provide good shielding against magnetic fields, the magnetic fields generated by the permanent magnets will not interfere with each other. Similarly, photoelectric detection devices can be independently installed at the rotating shafts of each spray arm, and the installation positions of each light emitting unit and light receiving unit are isolated from each other, ensuring that the optical paths do not overlap and eliminating the problem of mutual interference.

[0067] In a preferred embodiment of the present invention, the fault self-clearing process can adopt different execution strategies depending on the type of fault. When the controller determines that a fault is a type I, i.e., the sensing signal disappears, corresponding to a blocked spray arm or a completely blocked water distribution valve, the self-clearing process preferentially adopts a high-temperature heating method. This is because such faults are usually caused by grease coagulation or protein-based dirt solidification, resulting in jamming between the mating surfaces of the rotating shaft 1 and the bearing seat 2, or the valve core of the water distribution valve being stuck with grease. High-temperature heating can effectively dissolve the grease blockage, thereby relieving the jamming state.

[0068] When the controller determines that a Class II fault exists, i.e. the sensing signal is present but abnormal, corresponding to partial blockage of the water distribution valve or spray hole, the self-cleaning process prioritizes increasing the speed of the washing pump. This is because such faults are usually caused by fibrous residue or small particles blocking part of the spray hole or water distribution valve channel. High-speed water flow can generate greater flushing force to wash away these blockages.

[0069] Of course, in practice, both high-temperature heating and increased washing pump speed can be used simultaneously to achieve the best troubleshooting effect. For example, first, the heating device can be started to heat the water flow to a preset temperature and maintain that temperature for a period of time. Then, the washing pump speed can be increased to allow the high-temperature, high-speed water flow to jointly flush the clogged area. After the preset self-cleaning time, the controller will check the fault status again and decide whether to resume the washing process or issue a fault alarm based on the detection results. When the controller issues a fault alarm signal, it can also output fault type information to guide users or maintenance personnel to quickly locate the faulty part.

[0070] It should be noted that the above description is not intended to limit the present invention, and the present invention is not limited to the examples given above. Any changes, modifications, additions, or substitutions made by those skilled in the art within the scope of the present invention, such as splitting and combining the contents of the above embodiments to implement several safety control schemes, should also fall within the protection scope of the present invention.

Claims

1. A method for detecting faults in a dishwasher spray system, the dishwasher comprising a washing chamber and a spray system disposed within the washing chamber; the spray system comprising a plurality of spray arms and a water distribution valve responsible for switching different water paths to different spray arms; each spray arm being provided with a rotating shaft for driving the spray arm to rotate and a bearing for supporting the rotating shaft; characterized in that, The dishwasher further includes a first fault detection device; the first fault detection device includes a permanent magnet and an electromagnetic induction unit, wherein the permanent magnet is mounted on a rotating shaft, and the electromagnetic induction unit is mounted on a shaft seat; the detection method includes: During dishwasher operation, the sensing signal output by the electromagnetic induction unit is continuously monitored; If the sensing signal matches the set rules, it is determined that the sprinkler system is not malfunctioning. If the sensing signal does not conform to the set rules or disappears, it is determined that the sprinkler system has malfunctioned.

2. The dishwasher spray system fault detection method according to claim 1, characterized in that, The dishwasher also includes a second fault detection device; the second fault detection device includes a light emitting unit and a light receiving unit arranged on the bearing seat, and the two are arranged opposite to each other; and a light-transmitting channel is opened at the same height position as the light emitting unit and the light receiving unit on the rotating shaft. The detection method further includes: During dishwasher operation, the photoelectric conversion signal output by the light receiving unit is continuously monitored; If the photoelectric conversion signal is a pulse signal with a set rule, then the sprinkler system is determined to be without fault. If the photoelectric conversion signal is a pulse signal that does not conform to the set rules or disappears, it is determined that the sprinkler system has malfunctioned.

3. The dishwasher spray system fault detection method according to claim 2, characterized in that, The detection method further includes: If the sensing signal and the pulse signal continuously reflect the same fault information within a preset time period, then the fault is confirmed to have occurred. If the fault information reflected by the sensing signal and the pulse signal within a preset time period is inconsistent, it is determined to be an interference fault.

4. The dishwasher spray system fault detection method according to claim 2, characterized in that, The detection method further includes: If the sensing signal and / or the pulse signal briefly show fault information within a preset time period, it is determined to be a self-eliminating transient fault.

5. The dishwasher spray system fault detection method according to claim 1, characterized in that, If the sensing signal does not conform to the set rules, the sprinkler system is judged to be malfunctioning, specifically including: If the sensing signal disappears, it is determined that a type of fault has occurred in the sprinkler system; the type of fault is that the sprinkler arm is blocked or the water distribution valve is completely blocked, resulting in the complete misalignment of the water distribution plate. If the sensing signal exists but does not conform to the set rules, it is determined that the sprinkler system has a type II fault; the type II fault is that the water distribution valve is blocked, causing the water distribution plate to be misaligned or the sprinkler holes to be blocked.

6. A dishwasher, comprising: Washing chamber; A spray system configured within the washing chamber includes several spray arms and a water distribution valve responsible for switching different water paths to different spray arms; wherein each spray arm is equipped with a rotating shaft for driving the spray arm to rotate and a bearing for supporting the rotating shaft; characterized in that the dishwasher further includes: The first fault detection device includes a permanent magnet and an electromagnetic induction unit; wherein the permanent magnet is mounted on a rotating shaft and the electromagnetic induction unit is mounted on a shaft seat. The controller, connected to the electromagnetic induction unit, is configured to: During dishwasher operation, the sensing signal output by the electromagnetic induction unit is continuously monitored; If the sensing signal matches the set rules, it is determined that the sprinkler system is not malfunctioning. If the sensing signal does not conform to the set rules or disappears, it is determined that the sprinkler system has malfunctioned.

7. The dishwasher according to claim 6, characterized in that, The dishwasher also includes: The second fault detection device includes a light emitting unit and a light receiving unit arranged on the bearing, and the two are arranged opposite to each other. A light-transmitting channel is provided at the same height as the light emitting unit and the light receiving unit, located on the rotating shaft. The controller is also configured to: During dishwasher operation, the photoelectric conversion signal output by the light receiving unit is continuously monitored; If the photoelectric conversion signal is a pulse signal with a set rule, then the sprinkler system is determined to be without fault. If the photoelectric conversion signal is a pulse signal that does not conform to the set rules or disappears, it is determined that the sprinkler system has malfunctioned.

8. The dishwasher according to claim 7, characterized in that, The control is also configured to: If the sensing signal and the pulse signal continuously reflect the same fault information within a preset time period, then the fault is confirmed to have occurred. If the fault information reflected by the sensing signal and the pulse signal within a preset time period is inconsistent, it is determined to be an interference fault.

9. The dishwasher according to claim 7, characterized in that, The control is also configured to: If the sensing signal and / or the pulse signal briefly show fault information within a preset time period, it is determined to be a self-eliminating transient fault.

10. The dishwasher according to claim 6, characterized in that, When the controller determines that a fault has occurred in the sprinkler system, it is configured to: If the sensing signal disappears, it is determined that a type of fault has occurred in the sprinkler system; the type of fault is that the sprinkler arm is blocked or the water distribution valve is completely blocked, resulting in the complete misalignment of the water distribution plate. If the sensing signal exists but does not conform to the set rules, it is determined that the sprinkler system has a type II fault; the type II fault is that the water distribution valve is blocked, causing partial misalignment of the water distribution plate or blockage of the sprinkler holes.

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