Refrigerator

Abstract

This application provides an automatic door opening and closing device for a refrigerator, comprising a drive mechanism, a transmission mechanism including a planetary gear clutch unit, and a revolving door mechanism. The planetary gear clutch unit includes: a sun gear, at least one planetary gear, a planet carrier, and a gear ring having internal teeth meshing with at least one planetary gear and external teeth disposed radially outward therefrom. The clutch actuator has a slider that can be actuated and moved linearly, the slider having a toothed portion that engages with the external teeth. The clutch actuator actuates the slider to maintain it in the position engaged with the external teeth by a holding force. The holding force is configured to be greater than the disengagement force generated by the non-rectangular tooth profile and acting on the slider when the drive mechanism normally drives the revolving door mechanism, and less than the disengagement force generated by the non-rectangular tooth profile and acting on the slider when the door body driven by the revolving door mechanism is subjected to an external impact exceeding a predetermined value. The automatic door opening and closing device of this application has a simplified structure and high reliability.

Description

Technical Field

[0001] This application relates to the field of household appliance technology, and more particularly to a refrigerator. Background Technology

[0002] Implementing automatic door opening and closing functionality in refrigerators is fundamental for enhancing user experience, enabling remote control, and facilitating intelligent food management. Under the technical theme of automatic door opening and closing devices, the technology primarily revolves around three core modules: power drive, motion transmission, and door execution. Current mainstream solutions overcome the self-closing forces of the refrigerator door (such as door seal suction and suction aid gripping force) and the initial flipping torque of the flip beam in side-by-side refrigerators, generally employing a composite drive technology combining a "top-door mechanism" and a "rotating door mechanism." The top-door mechanism provides a linear push force during the initial opening phase to overcome significant static resistance; the rotating door mechanism then follows up after the door has opened to a certain angle, driving the door to complete subsequent large-angle opening and closing movements. However, this technical approach, focused on specific functional modules (top-door and rotating door collaboration scenarios), is gradually revealing inherent technical bottlenecks in the industry's pursuit of higher integration, better user experience, and lower manufacturing costs.

[0003] However, the commonly used "top door mechanism + rotating door mechanism" composite drive method in existing or mainstream technologies has several product performance defects in practical applications. First, at the structural level, this solution results in a large number of system components and a complex structure, which not only increases manufacturing costs and assembly difficulty but also makes it difficult to reduce the overall size of the automatic door opening and closing actuator, limiting its placement flexibility in the compact space of a refrigerator. Second, at the motion performance level, there is an unavoidable switching process between the linear pushing action of the top door mechanism and the rotational swinging action of the rotating door mechanism. To ensure that the two do not interfere with each other and achieve power handover, elastic transition elements such as springs are often required between the drive linkage and the drive groove. During the automatic door opening process, when the door passes through the self-closing force cam structure such as the suction aid, the opening direction thrust on the door will cause the drive linkage to move within the groove, resulting in a decrease in motion smoothness, producing a jerky feeling, and seriously affecting the user experience. Furthermore, in order to obtain sufficient push force, the push rod stroke and extension position of the door mechanism need to be far away from the door hinge. This often results in the push rod extending significantly beyond the refrigerator body when in operation, and a large fitting gap is also required when not in operation, which seriously damages the overall integrity and aesthetics of the refrigerator's appearance.

[0004] Therefore, a new technical solution is urgently needed to solve the problems of complex structure, uneven movement, and damage to appearance integrity, so as to meet the market demand for high-performance, high-reliability, and aesthetically pleasing automatic door opening and closing functions for refrigerators. Summary of the Invention

[0005] This application provides a refrigerator whose automatic door opening and closing device integrates three major functions—deceleration and torque increase, mode switching, and mechanical overload protection—into a compact unit, resulting in a simplified structure and high reliability.

[0006] In a first aspect, an automatic door opening and closing device for a refrigerator is provided, comprising: Drive mechanism, transmission mechanism, and rotary door mechanism, The transmission mechanism is used to transmit the power output by the drive mechanism to the rotary door mechanism, and the rotary door mechanism is used to connect to and drive the refrigerator door. The transmission mechanism includes a planetary gear clutch unit, which includes a sun gear connected to the output end of the drive mechanism. At least one planetary gear meshes with the sun gear; The planetary carrier is rotatably connected to at least one planetary gear and serves as the drive input end of the rotary door mechanism; A gear ring has internal teeth that mesh with the at least one planetary gear and external teeth disposed radially outward therefrom; A clutch actuator has a slider that can be actuated and moved in a straight line, the slider having a toothed portion that engages with the external teeth; The slider has a first position and a second position: In the first position, the toothed portion engages with the external tooth to restrict the rotation of the gear ring; In the second position, the toothed portion disengages from the external teeth, and the toothed ring can rotate freely; The tooth profile surface that meshes with the toothed portion is a non-rectangular tooth profile with a tooth angle, and the holding force provided by the clutch actuator to keep the slider in the first position is denoted as F1. When the drive mechanism (100) normally drives the rotary door mechanism (300), the component force in the disengagement direction generated by the non-rectangular tooth profile and acting on the slider (252) is denoted as F2. When the door body driven by the revolving door mechanism (300) is subjected to an external impact exceeding a predetermined value, the component force in the disengagement direction generated by the non-rectangular tooth profile and acting on the slider (252) is denoted as F3. Where F2≤F1≤F3.

[0007] The above technical solution breaks away from the conventional thinking of separating deceleration, clutch, and overload protection functions into separate designs. This solution cleverly utilizes the controllability of the gear ring and the mechanical characteristics of the tooth profile in a planetary gear system, integrating the three major functions of deceleration and torque increase, mode switching, and mechanical overload protection into a compact unit. This solution not only meets the requirements of efficient power transmission and on-demand clutch engagement in automatic mode, but also satisfies the passive protection requirements when the control system cannot respond to transient impacts in time through a purely mechanical means. It solves the problems of traditional solutions, such as numerous parts, loose structure, and susceptibility to damage under accidental impacts, achieving a comprehensive effect of structural simplification, cost reduction, and improved reliability.

[0008] In some embodiments, the non-rectangular tooth profile is a trapezoidal tooth profile.

[0009] The above technical solutions specifically define non-rectangular tooth profiles as trapezoidal tooth profiles commonly used in the technology, providing a clear and easy-to-manufacture specific tooth profile solution, clarifying the physical structural basis for realizing the generation of the radial component force, and enhancing the feasibility and certainty of the above technical solutions.

[0010] In some embodiments, the tooth profile half-angle of the non-rectangular tooth profile is denoted as α, and the range of the tooth profile half-angle α is determined based on the rated output torque of the drive mechanism, the estimated external impact torque above the predetermined value, and the rated holding force of the clutch actuator.

[0011] The above technical solutions define the key design parameter of tooth profile half-angle and its determination basis, providing a quantifiable design and verification physical basis for the "mechanical overload protection" function. This enables technicians to accurately design the tooth profile based on the specific motor torque, expected impact force, and electromagnet performance, ensuring the controllability and predictability of the overload protection threshold.

[0012] In some embodiments, the tooth profile half-angle α ranges from 2 degrees to 30 degrees.

[0013] The above technical solutions provide a specific numerical range for the tooth profile half-angle, further defining the engineering practice boundaries of tooth profile design. When α < 2°, an excessively small tooth profile half-angle may result in insufficient radial force, making reliable disengagement under impact difficult.

[0014] When α > 30°, an excessively large tooth profile half-angle will result in an excessively large electromagnet holding force required to maintain locking under normal operating conditions, increasing costs and energy consumption.

[0015] The setting of 2°≤α≤30° allows for a good balance between locking reliability and overload protection sensitivity within the range of conventional electromagnet selection and impact load estimation.

[0016] In some embodiments, the clutch actuator includes an electromagnetic actuator, the push rod of which is connected to the slider for driving the slider to move between the first position and the second position.

[0017] The above technical solution concretizes the clutch actuator into one that includes an electromagnetic actuator, and clarifies the common and controllable power source for realizing the linear movement of the slider. This enables the mode switching to respond quickly and accurately to the electronic control signal, facilitating integration with the refrigerator control system and realizing complex automatic logic.

[0018] In some embodiments, when the slider is in the first position, the number of meshing teeth between its toothed portion and the outer teeth of the toothed ring is at least one.

[0019] The above technical solutions limit the lower limit of the number of meshing teeth and clarify the basic conditions for the locking state. Even with single-tooth meshing, as long as the tooth profile strength and electromagnet holding force meet the requirements, the function can be achieved, which provides design flexibility (such as saving axial space). In addition, multi-tooth meshing can improve locking reliability.

[0020] In some embodiments, the outer teeth of the gear ring are distributed along its entire circumference, and the toothed portion of the slider has at least one tooth that meshes with the outer tooth groove.

[0021] The above technical solution limits the external teeth to be distributed around the entire circumference and the slider to have matching tooth grooves, ensuring that the slider can find a tooth groove to mesh with when the electromagnetic actuator is activated at any circumferential position, realizing the function of "disengagement at any position", improving the user experience and the level of system intelligence.

[0022] In some embodiments, the outer teeth of the gear ring are specifically designed to engage with the slider of the clutch actuator, and do not participate in the power transmission within the planetary gear clutch unit.

[0023] The above technical solutions clarify the functional specialization of the external gears and emphasize that their design is decoupled from the design principles of the internal gears (used for transmission). This allows for independent optimization of the external gear tooth profile (such as using a specific tooth profile half-angle) for requirements such as locking and overload protection, without being limited by the gear transmission meshing principle (such as involute).

[0024] In some embodiments, the direction of movement of the slider is consistent with the radial direction of the gear ring.

[0025] The above technical solution clarifies that the slider moves radially along the gear ring, making the engagement and disengagement of the slider's toothed portion with the external teeth most direct and efficient, with a clear force flow path. This radial engagement method is the most natural and compact structural layout for realizing the aforementioned "radial separation force" mechanism, avoiding complex motion conversion mechanisms.

[0026] In some embodiments, the clutch actuator further includes a limiting structure for limiting the travel of the slider.

[0027] The above technical solution adds a limiting structure, which ensures that the slider can accurately and reliably reach the first position (fully engaged) and the second position (fully disengaged), preventing poor engagement due to insufficient stroke or mechanical interference due to overshoot, and improving the reliability and consistency of clutch action.

[0028] In some embodiments, the sun gear and the input gear are coaxially fixedly arranged to form a double gear structure.

[0029] The above technical solution defines the sun gear and input gear as a coaxial, fixed double gear structure, providing a compact and highly rigid power input component configuration. This integrated or fixed connection design reduces the number of parts, improves transmission accuracy and structural strength, and is an effective means of achieving a compact layout.

[0030] In some embodiments, the diameter of the input gear in the double gear structure is larger than the diameter of the sun gear.

[0031] The above technical solution limits the input gear diameter to be larger than the sun gear, which indicates that there is a reduction stage between the drive motor and the sun gear. This helps to further reduce the torque requirements of the drive motor, allows for the selection of smaller and more economical motors, and optimizes the overall cost and size of the system.

[0032] In some embodiments, the planetary carrier is a plate-like structure with a support shaft for mounting at least one of the planetary gears, and a portion of the planetary carrier extends outward to form a drive arm for driving the rotary door mechanism.

[0033] The above technical solutions specify the planetary carrier as a plate-like structure with a support shaft and a drive arm, clarifying its specific form as both a support component and a power output component. The plate-like structure helps reduce axial dimensions, enabling a flattened design for the device; the integrated drive arm makes the structure simpler.

[0034] In some embodiments, the number of the at least one planetary gear is three, and they are evenly distributed along the circumference of the sun gear.

[0035] The above technical solution, which specifically limits the number of planetary gears to three, provides a preferred embodiment that offers uniform load distribution, smooth operation, and efficient space utilization. Three planetary gears are the most common and mature configuration in planetary gear systems, achieving a balance between performance and cost.

[0036] In some embodiments, the revolving door mechanism includes a link, a first end of which is hinged to the planetary carrier, a second end of which is hinged to a hinge bracket disposed on the refrigerator door, and the link is at least partially bent.

[0037] The above technical solution defines the specific shape characteristics (bent) of the connecting rod and its function (avoiding interference), providing a key design detail for the revolving door mechanism. This reflects the design consideration of kinematic avoidance within a compact space, a necessary feature to ensure the mechanism functions properly throughout its entire stroke.

[0038] In some embodiments, the curved portion of the link is referred to as the bend; the bend is located near the hinge point between the link and the planetary carrier, relative to the hinge point between the link and the hinge frame. The length of the bent portion is less than half the total length of the connecting rod.

[0039] The above technical solution limits the position of the bent part of the linkage to avoid interference with the hinge assembly connecting the door and the box when the door is opened; on the other hand, it makes the door closer to the box and door structure after it is opened.

[0040] In some embodiments, an angle detection unit is further included, which is configured to detect the rotation angle of the planetary carrier.

[0041] The above technical solutions, by adding an angle detection unit, enable closed-loop control of automatic door opening and closing (such as positioning control, speed adjustment, and obstacle detection), and are fundamental technical features for improving the intelligence, precision, and user experience of automatic door opening and closing.

[0042] In some embodiments, the angle detection unit includes a first gear portion disposed on the planetary carrier, a second gear meshing with the first gear portion, and an angle sensor connected to the shaft of the second gear.

[0043] The above technical solution provides a specific implementation plan for high-precision angle detection. By using gear transmission, the large-angle rotation of the planetary carrier is converted into a small-angle rotation of the angle sensor shaft, thereby amplifying and accurately measuring the angle signal and laying the foundation for high-precision control.

[0044] In some embodiments, the angle detection unit includes a first position sensor and a second position sensor fixed to the refrigerator body, and a trigger part that moves with the planetary frame. The trigger part is configured to trigger the first position sensor and the second position sensor respectively when the door reaches the closed position and the maximum open position.

[0045] The above technical solution provides a low-cost angle detection solution. It uses two fixed points to detect the position of the door instead of continuous angle measurement. While ensuring the basic automatic door opening and closing function (stopping when the door is in position), it significantly reduces the system cost and expands the application market of this technology (low-end models).

[0046] In some embodiments, the clutch actuator is configured to: actuate the slider to the first position only when the drive mechanism needs to output power to drive the door; and hold or release the slider to the second position when the drive mechanism does not output power.

[0047] The above technical solution defines the clutch's operating timing logic, achieving an energy-saving and safety strategy where "automatic mode is only engaged when needed, and manual mode is maintained at other times." This reduces the energizing time of the electromagnetic actuator, lowers energy consumption and heat generation, while ensuring that the door can be freely operated manually during non-active driving periods, improving safety and user experience.

[0048] In some embodiments, the holding force of the clutch actuator actuating the slider is determined based on the torque transmitted to the gear ring by the drive mechanism when it is running under rated load, and the first radial force component calculated from the tooth profile half angle of the non-rectangular tooth profile, and then a safety factor is added.

[0049] The above technical solutions further clarify the engineering method for determining the holding force of an electromagnet, directly linking it to the normal operating torque and tooth profile parameters of the system, thus giving the functional limitation of "greater than the disengagement force during normal driving" a calculable and verifiable technical connotation.

[0050] In some embodiments, the external impact exceeding the predetermined value refers to an impact that causes the instantaneous torque transmitted to the gear ring to exceed 1.5 to 3 times the rated output torque of the drive mechanism.

[0051] The above technical solutions provide a quantitative reference range for "external impacts exceeding a predetermined value," clarifying the trigger threshold for mechanical overload protection. This range definition avoids setting the threshold to be too sensitive (leading to false tripping) or too insensitive (loss of protection), providing an objective standard for evaluating overload protection performance.

[0052] In some embodiments, the relative positional relationship between the lengths of each link of the revolving door mechanism and each hinge point is determined based on an optimization algorithm aimed at minimizing the maximum driving torque required by the planetary carrier during the automatic opening and closing of the refrigerator door.

[0053] The above technical solution combines the optimization of the rotary door mechanism parameters with the planetary gear clutch unit, and summarizes the optimization algorithm at a higher level, forming a more complete and higher-level invention solution. This optimization ensures the high efficiency of the actuator itself, thereby reducing the capability requirements of the transmission system and drive mechanism from the source, resulting in system-level synergistic efficiency.

[0054] In some embodiments, the constraints of the optimization algorithm include: when the door is manually operated, the additional resistance torque introduced by the revolving door mechanism is between 0.5 Nm and 4 Nm.

[0055] The above technical solutions clarify a key constraint in the optimization process: balancing the efficiency of automatic driving with the ease of manual operation. This ensures that while achieving automatic functions, the invention does not burden users' daily manual use, reflecting a user-friendly overall design philosophy.

[0056] In some embodiments, the refrigerator door is the refrigerator compartment door of a side-by-side refrigerator, and the door is equipped with a suction device that generates a self-closing force and / or a rotatable rotating beam. The above technical solution precisely defines the application as the refrigerator compartment door of a side-by-side refrigerator and clarifies its features of having a suction device and a rotating beam, thus anchoring the scope of protection of this invention to products that have the specific technical problem of "large initial self-closing force and the need to overcome the flipping torque."

[0057] In some embodiments, the clutch actuator further includes a reset elastic element that acts on the slider to provide an elastic force that moves it toward the second position.

[0058] The above technical solution incorporates a reset elastic element, providing a safety redundancy mechanism that automatically disengages the slider and switches to manual mode in the event of a power outage or other malfunction of the electromagnetic actuator. This further enhances the system's fail-safe characteristics, ensuring that users can still manually open and close the door even in the event of a circuit failure, thus improving the product's reliability and safety.

[0059] In some embodiments, a sliding bearing or a rolling bearing is provided between the planetary gear and the support shaft on the planet carrier.

[0060] The above technical solutions define the support method for the planetary gears and provide specific implementation methods to reduce friction, improve transmission efficiency, and ensure long-term operational reliability. The selection of bearings is one of the key details affecting the lifespan and noise of the planetary gear system.

[0061] In some embodiments, the gear ring is rotatably supported on the housing or bracket of the planetary gear clutch unit by bearings.

[0062] The above technical solutions clarify the support method of the gear ring in manual mode, ensuring its stability and flexibility in free rotation, avoiding jamming or eccentric friction, and are important structural features to ensure smooth manual operation. Attached Figure Description

[0063] Figure 1 An exemplary schematic diagram of a refrigerator having an automatic door opening and closing device according to some embodiments is shown; Figure 2 An exemplary schematic diagram of a refrigerator having an automatic door opening and closing device when the door is closed, according to some embodiments, is shown. Figure 3 An exemplary schematic diagram of a partial structure of a refrigerator automatic door opening and closing device according to some embodiments is shown; Figure 4 An exemplary schematic diagram of the assembly structure of an automatic door opening and closing device for a refrigerator according to some embodiments is shown; Figure 5 An exemplary cross-sectional view of a refrigerator automatic door opening and closing device according to some embodiments is shown; Figure 6 An exploded view of a refrigerator automatic door opening and closing device according to some embodiments is shown as an example; Figure 7 An exploded view of a refrigerator automatic door opening and closing device according to some embodiments is shown as an example; Figure 8 An exemplary schematic diagram of a clutch actuator according to some embodiments is shown; Figure 9 An exploded structural diagram of a clutch actuator according to some embodiments is shown as an example; Figure 10 An exemplary schematic diagram is shown of the structure when the toothed portion meshes with the external tooth according to some embodiments; Figure 11 An exemplary schematic diagram of the structure when the toothed portion is separated from the external tooth according to some embodiments is shown; Figure 12 An exemplary schematic diagram of a refrigerator door according to some embodiments is shown when it is opened to a first angle; Figure 13 An exemplary schematic diagram of a refrigerator door opened to 90° according to some embodiments is shown; Figure 14 An exemplary schematic diagram of a refrigerator door opened to a second angle according to some embodiments is shown; Figure 15 An exemplary simplified kinematic model of a revolving door mechanism for an automatic door opening and closing process according to some embodiments is shown.

[0064] The components include: a drive mechanism 100; a drive motor 110; an output gear 120; a planetary gear clutch unit 200; an input gear 210; a sun gear 212; a planetary gear 220; a planetary carrier assembly 230; a support shaft 231; a rocker arm 603; a gear ring 240; internal gears 241; external gears 242; a clutch actuator 250; an electromagnetic actuator 251; a slider 252; a limiting structure 253; a toothed portion 254; a limiting block 255; a first limiting wall 2531; a second limiting wall 2532; a revolving door mechanism 300; a connecting rod 310; a hinge frame 320; a first gear portion 232; a second gear 400; and an angle sensor 500. Detailed Implementation

[0065] To make the objectives and implementation methods of this application clearer, the exemplary implementation methods of this application will be clearly and completely described below with reference to the accompanying drawings of the exemplary embodiments of this application. Obviously, the exemplary embodiments described are only some embodiments of this application, and not all embodiments.

[0066] like Figures 1-12 The diagram shows the system framework of the automatic refrigerator door opening and closing device provided in this application. The automatic refrigerator door opening and closing device includes: a drive mechanism 100, a planetary gear clutch unit 200, a door rotating mechanism 300, an angle detection unit, and a control unit (not shown). The collaborative relationship between the units is as follows: the control unit, as the system decision-making core, receives user commands and feedback signals from the angle detection unit, and sends control signals to the drive mechanism 100 and the clutch actuator 250 in the planetary gear clutch unit 200 based on user commands or sensor signals. The drive mechanism 100, as the power source, generates power that is decelerated, increased in torque, and switched between automatic and manual modes through the planetary gear clutch unit 200, and then transmitted to the door rotating mechanism 300, ultimately converting the rotational motion into the opening and closing swing of the refrigerator door. The door rotating mechanism 300 converts the rotational motion into the swing of the door. The angle detection unit monitors the angular position of the output shaft of the door rotating mechanism 300 or the planetary gear clutch unit 200 in real time and feeds it back to the control unit, forming a closed-loop control or position determination.

[0067] In some embodiments of this application, such as Figures 1-7 As shown, the drive mechanism 100 may include a drive motor 110 and an output gear 120 fixed to its output shaft. The drive motor 110 may be a DC brushed motor, a DC brushless motor, or a stepper motor, and integrates a reducer such as a planetary gear or a worm gear to provide low-speed, high-torque output within a compact size. The output gear 120 is fixed to the motor output shaft by means of key connection, press fitting, or screw fastening.

[0068] The drive mechanism 100 serves to provide the driving force in the system. For example, when an automatic door opening action is required, the control unit supplies power to the drive motor 110 and controls it to rotate in a preset direction and speed. The built-in reducer of the drive motor 110 first reduces the speed and increases the torque, then drives the output gear 120 to rotate via the output shaft. In other embodiments, the drive mechanism 100 can also be a regular motor without an integrated reducer; in this case, one or more external gear reduction stages need to be added between the motor and the output gear 120.

[0069] The positional relationship between the drive mechanism 100 and the planetary gear clutch unit 200 in the system is such that its output gear 120 directly meshes with the input gear 210 of the planetary gear clutch unit 200. This meshing relationship constitutes the first-stage power transmission path from the power source to the core transmission unit. For example, the axis of the output gear 120 is coaxial with the axis of the drive motor 110, while the axis of the input gear 210 is coaxial with the axis of the sun gear 212 of the planetary gear clutch unit 200. The two pairs of axes are parallel, and the gear pairs mesh in a parallel plane.

[0070] During dynamic operation, when the system is in automatic mode, the drive mechanism 100 starts according to control commands, and the output gear 120 rotates continuously to transmit power. When the system is in manual mode or standby mode, the drive mechanism 100 is powered off, and the output gear 120 remains stationary. In some embodiments requiring precise position control, the drive mechanism 100 may be a stepper motor or a servo motor with an encoder, and the control unit precisely controls the motor angle through pulses or feedback signals.

[0071] The sun gear 212 is coaxially fixed with the input gear 210. The drive mechanism 100 includes a drive motor 110 and an output gear 120 driven by the drive motor 110. The output gear 120 meshes with the input gear 210.

[0072] In some embodiments of this application, the gear ratio between the output gear 120 of the drive mechanism 100 and the input gear 210 of the planetary gear clutch unit 200 is designed to provide a single-stage reduction. For example, the output gear 120 is a pinion and the input gear 210 is a large gear, thereby providing initial speed reduction and torque increase before entering the planetary gear system. This helps to further reduce the torque and size requirements of the drive motor 110. This reduction ratio can be matched and designed according to the final torque required for the door body and the motor selection.

[0073] Unlike other similar technologies (or existing technologies), the output torque and power required by the drive mechanism 100 in this solution are jointly determined by the subsequently deeply optimized rotary door mechanism 300 and the high-efficiency integrated planetary gear clutch unit 200. Therefore, a smaller, lower-cost motor can be selected. In other similar technologies (or existing technologies), due to the low efficiency of the actuator and the potentially long and inefficient transmission chain, a motor with greater power and torque is often required to overcome system losses and initial high resistance, leading to increased cost and size. Therefore, the two technologies result in different motor selection and system energy efficiency, thus this solution achieves optimization of overall cost and size.

[0074] In some embodiments of this application, the housing of the planetary gear clutch unit 200 can be composed of upper and lower covers. The housing can be made of high-strength engineering plastics (such as POM, PA66+GF) or die-cast metal (such as aluminum alloy); the housing has precise bearing seats and gear mounting positions inside to accommodate and support all internal gears and shaft components. The housing not only encapsulates and protects the internal gear train but also provides a mounting interface for fixing to the refrigerator body and a base for mounting the clutch actuator 250. The housing is typically flattened cylindrical or square-round to fit the mounting space reserved on the side wall or top of the refrigerator.

[0075] In some embodiments of this application, such as Figures 2-7 As shown, the planetary gear clutch unit 200, based on its internally integrated planetary gear system and specially designed gear ring-slider clutch actuator, plays a core role in the system for deceleration and torque increase, automatic / manual mode switching, and mechanical overload protection. For example, in automatic mode, the planetary gear clutch unit 200 converts the high-speed, low-torque power input from the drive mechanism 100 into low-speed, high-torque power output to the turntable mechanism 300 through the deceleration effect of the planetary gear system. Simultaneously, the planetary gear clutch unit 200 allows the control system to connect or disconnect this power transmission path at any time via electrical signals, thereby controlling the rotational freedom of its internal gear ring 240 and switching between "automatic mode with closed power transmission path" and "manual mode with open power transmission path." Furthermore, the unique tooth profile design of the planetary gear clutch unit 200 gives it the passive protection capability of automatically cutting off power transmission under extreme impacts. When the output end is subjected to an instantaneous impact exceeding the design range, the planetary gear clutch unit 200 can automatically and physically disengage, protecting the internal gears. In other embodiments, the overload protection function can also be achieved through other mechanical means (such as friction plates or shear pins), but the toothed disengagement method of this solution is more direct, compact, and repositionable. In other embodiments, the reduction ratio and structural layout (such as the number of planetary gears) of the planetary gear clutch unit 200 can be adjusted according to the installation space and torque requirements of different refrigerator models.

[0076] The planetary gear clutch unit 200 has a clear hierarchy in its connection with other units in the system. Specifically, the planetary gear clutch unit 200 is connected to the drive mechanism 100 and the rotary door mechanism 300 in such a way that the input side of the planetary gear clutch unit 200 forms an external meshing gear pair with the output gear 120 of the drive mechanism 100 through the sun gear 212 or its coaxial input gear 210.

[0077] The output side of the planetary gear clutch unit 200 is directly or indirectly hinged to the drive input end (such as a connecting rod) of the rotary door mechanism 300 via the planet carrier 230 (such as a rocker arm).

[0078] In some embodiments of this application, the gear ring 240 is supported on the housing by bearings, allowing it to rotate freely; alternatively, the gear ring 240 may be supported on the housing by deep groove ball bearings or sliding bearings, allowing it to rotate freely about its own axis. The gear ring 240 has external teeth.

[0079] In some embodiments of this application, the gear ring 240 can be integrally formed using powder metallurgy to ensure the precision and strength of the internal teeth 241 and the external teeth 242. The material is generally iron-based powder metallurgy, which can be steam-treated or oil-impregnated to improve wear resistance. The gear ring body may be designed with reinforcing ribs to reduce weight and ensure rigidity.

[0080] The internal teeth 241 of the gear ring assembly 240, as standard components of the planetary gear system, participate in power transmission and reduction calculations. Its external teeth 242, as characteristic components of this invention, are dedicated to interacting with the clutch actuator to achieve mode locking and mechanical overload protection, and their functions are completely decoupled from the transmission function of the internal teeth.

[0081] The gear ring 240 is located on the outermost side of the unit. Its internal teeth 241 face inward and mesh with the planetary gear 220. Its external teeth 242 face outward so as to contact the slider 252 of the clutch actuator 250. The gear ring 240 is supported on the corresponding bearing seat of the housing through the bearing mounting surface on its outer cylindrical surface or end face flange, so that it can rotate freely about an axis coaxial with the sun gear and planet carrier.

[0082] During dynamic operation, the state of the gear ring 240 determines the working mode of the entire unit. In the automatic locking state, the gear ring is fixed by the slider and remains stationary. In the manual free state, the gear ring can rotate freely, and its rotational speed satisfies the kinematic relationship of the planetary gear system with the planet carrier speed and the sun gear state. At the moment the impact protection disengages, the gear ring is forcibly driven to rotate a very small angle from rest to release the impact energy, and then enters the free rotation state.

[0083] In some embodiments of this application, such as Figures 2-9As shown, the clutch actuator 250 mainly includes an electromagnetic actuator 251, a slider 252, a return spring (unlabeled), and possible guide and limit components. The electromagnetic actuator 251 is cylindrical or square and is fixed to the housing by screws. The slider 252 is usually made of metal or high-strength plastic, and its toothed portion 254 that meshes with the gear ring needs to have high hardness for wear resistance.

[0084] The clutch actuator 250 is the execution terminal that controls the switching of the working mode of the planetary gear clutch unit 200. According to the electrical signal of the control unit, it drives the slider 252 to make linear motion, thereby realizing the engagement and disengagement with the external teeth 242 of the gear ring 240, and thus switching the power transmission state of the entire transmission system.

[0085] The clutch actuator 250 is fixedly mounted on the side of the housing of the planetary gear clutch unit 200. The axis of the electromagnetic actuator 251 is parallel to the radial direction of the gear ring 240. The slider 252 is mounted in a linear guide or guide groove on the housing, ensuring that it can only slide radially along the gear ring. One end of the slider 252 is connected to the push rod of the electromagnet 251, and the other end is a toothed portion 254, which faces the outer teeth 242 of the gear ring 240. The return spring is usually sleeved on the push rod or installed between the slider and the housing.

[0086] During dynamic operation, when the control unit issues a "Enter Automatic Mode" command, it energizes the electromagnet 251. The push rod of the electromagnet 251 overcomes the force of the return spring, pushing the slider 252 along the guide rail towards the gear ring until the toothed part 254 engages with the external tooth 242 (may require motor micro-motion assistance), and remains in this position. When the control unit issues a "Exit Automatic Mode" command or the power is cut off, the electromagnet 251 is de-energized. The force of the return spring pulls or pushes the slider 252 away from the gear ring until the toothed part 254 completely disengages from the external tooth 242 and is blocked by the limiting structure 253, and the system switches back to manual mode.

[0087] The clutch actuator 250 is configured to actuate the slider 252 to the first position only when the drive mechanism 100 needs to output power to drive the door; and to hold or release the slider 252 to the second position when the drive mechanism 100 does not output power.

[0088] This is an optimized energy-saving and control strategy. The control unit logic can be as follows: The electromagnet 251 is energized and the slider is engaged only moment before the automatic door opening / closing action is initiated; after the automatic door opening / closing action is completed and the motor stops, the electromagnet power supply is disconnected after a very short delay (e.g., 0.5 seconds), releasing the slider. In this way, the electromagnet only works for a short period of time during the action, greatly reducing average power consumption, reducing heat generation, extending the electromagnet's lifespan, and ensuring that the system is in manual mode when the door is stationary, allowing the user to operate it manually at any time without waiting.

[0089] In some embodiments of this application, the clutch actuator 250 is fixedly mounted on the housing, and the slider 252 of the clutch actuator 250 can slide along the guide structure to interact with the outer teeth 242 of the gear ring 240. The slider 252 includes a toothed portion 254 for engaging with the outer teeth 242 of the gear ring 240. Thus, the movement path of the slider 252 of the clutch actuator 250 is restricted by the guide structure, ensuring that its toothed portion 254 can accurately contact or disengage from the outer teeth 242 of the gear ring 240.

[0090] During dynamic operation, the planetary gear clutch unit 200 has at least three key states: automatic locking state, manual free state, and impact disengagement state. In the first state, i.e., the automatic door opening state, the control unit first energizes the electromagnet 251 of the clutch actuator 250, pushing the slider 252 to attempt to engage with the gear ring 242. The slider 252 of the clutch actuator 250 is pushed out and held at the end of its stroke. If motor micro-motion assistance is required, the motor is controlled to move briefly. The toothed portion 254 of the clutch actuator 250 engages with the external teeth 242 of the gear ring 240. At this time, the rotational freedom of the gear ring 240 is completely restricted, equivalent to a fixed part. After confirming that the toothed portion 254 and the external teeth 242 of the gear ring 240 have engaged and locked, the control unit starts the drive mechanism 100 to rotate forward according to the preset speed curve. The power of the drive mechanism 100 is input through the sun gear 212, driving the planetary gear 220 meshing with it to rotate around its own axis. After the power is reduced and amplified by the planetary gear clutch unit 200, it drives the optimized revolving door mechanism 300 to smoothly open the door. Because the gear ring 240 is fixed, the rotation of the planetary gear 220 is forced to transform into revolution around the axis of the sun gear 212, thereby driving the planet carrier 230 to rotate in the same direction at a speed lower than the sun gear's rotational speed but with a force higher than the sun gear's torque, achieving reduced speed and increased torque output. The angle detection unit provides real-time feedback on the door angle. When the set opening angle is reached, the control unit stops the drive mechanism 100, then disconnects the power to the electromagnet 251, and the slider 252 resets under the action of the spring, switching the system back to manual mode.

[0091] In the second state, i.e., the manual free state, both the drive mechanism 100 and the clutch actuator 250 are de-energized. The slider 252 of the clutch actuator 250 retracts to its starting point of travel, and its toothed portion 254 completely disengages from the outer teeth 242 of the gear ring 240. At this time, the rotational freedom of the gear ring 240 is released, making it a freely rotatable component. When the user manually operates the door, the movement of the door is reverse-driven by the revolving door mechanism 300 to rotate the planetary carrier 230. The planetary carrier 230 drives the planetary gear 220 to revolve around the sun gear 212. Since the sun gear 212 usually has a certain resistance when the motor is not working (such as gear meshing friction, motor magnetic reluctance), the revolution of the planetary gear 220 will drive the gear ring 240 to rotate freely, thereby absorbing the reverse driving force, making manual operation easy, and the motor will not be forcibly dragged.

[0092] In the third state, i.e., the automatic door closing process, it is similar to the automatic opening and closing process, but the drive mechanism 100 reverses. If the angle detection unit detects obstruction of movement (such as abnormal angle change) during automatic operation, the control unit immediately cuts off the power supply to the electromagnet 251 and stops the motor, realizing active obstruction protection.

[0093] In the fourth state, i.e., the impact protection disengagement state, the system is initially in the first state (automatic door opening state). When the door body driven by the revolving door mechanism 300 is subjected to a sudden and violent external force impact, an impact torque far exceeding the normal driving torque is input in reverse through the planetary carrier 230. This impact torque is amplified through the planetary gear system and transmitted to the gear ring 240. The gear ring 240 bears a huge torque, and on the meshing inclined surface of its external teeth 242 and the tooth profile 254 of the slider 252, a huge radial component force is generated along the disengagement direction of the slider. This radial component force instantaneously exceeds the electromagnetic holding force (or combined with the mechanical holding force) used by the clutch actuator 250 to maintain the position of the slider, forcibly pushing the slider 252 to move in the disengagement direction, realizing mechanical overload protection. At the same time, the control unit detects an abnormality (such as motor stall current) and cuts off the power supply. Once the slider begins to move, the engagement disengages, and the gear ring 240 immediately returns to the free rotation state. The impact torque is released through the free rotation of the gear ring, and the transmission chain is physically cut off, thereby protecting the teeth of the sun gear, planet gears, etc. from overload damage. The entire system achieves safe, reliable, flexible, and efficient automatic door opening and closing functions through the precise coordination of electronic control logic and mechanical structure.

[0094] The tooth profile surface that meshes with the toothed portion 254 is a non-rectangular tooth profile with a tooth profile angle. The holding force provided by the clutch actuator 250 to actuate the slider 252 in the first position is configured to be greater than the disengagement direction component force generated by the non-rectangular tooth profile and acting on the slider 252 when the drive mechanism 100 normally drives the revolving door mechanism 300, and less than the disengagement direction component force generated by the non-rectangular tooth profile and acting on the slider 252 when the door body driven by the revolving door mechanism 300 is subjected to an external impact of more than a predetermined value.

[0095] In some embodiments of this application, the non-rectangular tooth profile is specifically a trapezoidal tooth profile. Trapezoidal tooth profiles have mature machining processes, high strength, and a clear trigonometric function relationship between their tooth profile angle (usually measured as tooth profile half-angle α) and the generated radial force. The tooth profile angle refers to the included angle formed between the two working surfaces of the tooth sides in a non-rectangular tooth profile (especially a trapezoidal tooth profile). For example... Figure 8 As shown, the tooth profile half-angle α is usually used to describe the inclination angle of a single tooth surface. The tooth profile half-angle α is half of the tooth profile angle. The tooth profile half-angle α is a key design parameter.

[0096] The outer teeth 242 of the gear ring 240 and the tooth profile 254 of the slider 252 adopt matching trapezoidal teeth. When the two mesh to transmit torque T, at the tooth surface contact point, the normal force on the tooth surface can be decomposed into a tangential force (used to transmit torque) and a radial force (perpendicular to the slider's movement direction, attempting to push the slider away). According to the principles of mechanics, the magnitude of this radial component force Fr is related to the torque T, the tooth profile half-angle α, and the meshing point radius r (which can be approximated by the pitch circle radius of the outer teeth of the gear ring), and its relationship can be characterized as: Fr = (T / r) * tan(α). It can be seen that under the same torque T, the larger the tooth profile half-angle α, the larger the radial component force Fr that attempts to push the slider away; and vice versa.

[0097] The holding force of the clutch actuator 250 actuating slider 252 is determined based on the torque transmitted to the gear ring 240 by the drive mechanism 100 under rated load and the first radial force value calculated from the tooth profile half angle of the non-rectangular tooth profile, and after adding a safety factor.

[0098] In the design process, it is first necessary to determine the maximum working torque Tnormal that the gear ring 240 needs to withstand during the normal automatic door opening and closing process. This torque can be calculated by multiplying the rated output torque of the drive motor 110 by the total transmission ratio from the motor to the gear ring 240 (including the transmission relationships of the motor reducer, the output gear 120 to the input gear 210, and the sun gear 212 to the gear ring 240). Then, based on the initial value of the selected tooth profile half angle α, the theoretical radial component force Frnormal generated under Tnormal is calculated using the formula. The rated holding force Fhold of the clutch actuator 250 (usually an electromagnet) must be greater than Frnormal and have a certain safety factor S (usually greater than 1, for example, S = 1.2 - 1.5) to ensure that the slider is absolutely reliably locked during normal operation, that is, it needs to satisfy: Fhold > S * Frnormal = S * (Tnormal / r) * tan(α). At the same time, a trigger threshold for mechanical overload protection, that is, an "external impact torque above a predetermined value" Timpact, needs to be set. The estimated value of this impact torque Timpact is usually based on the assessment of possible accidental impacts on the door body (such as being kicked forcefully by a person or being hit by a heavy object), and its value may be 1.5 to 3 times the normal maximum working torque Tnormal. The design needs to ensure that when the torque borne by the gear ring reaches Timpact, the generated radial component force Frimpact = (Timpact / r) * tan(α) can exceed the holding force Fhold of the electromagnet, thereby forcibly pushing open the slider, that is, it needs to satisfy: Fhold < Frimpact = (Timpact / r) * tan(α). By联立上述两个不等式,可以得出齿形半角α和电磁铁保持力Fhold的匹配设计窗口。通过调整α和Fhold,可以使系统既能在正常工作下可靠锁止,又能在预定冲击下可靠脱开。预定值以上的外部冲击,是指导致传递至齿圈240的瞬时扭矩超过驱动机构100额定输出扭矩1.5倍至3倍的冲击。

[0099] The value range of the tooth profile half angle α is from 2 degrees to 30 degrees.

[0100] It should be noted that there is an unclear part in the original text where it says "联立上述两个不等式,可以得出齿形半角α和电磁铁保持力Fhold的匹配设计窗口。通过调整α和Fhold,可以使系统既能在正常工作下可靠锁止,又能在预定冲击下可靠脱开。预定值以上的外部冲击,是指导致传递至齿圈240的瞬时扭矩超过驱动机构100额定输出扭矩1.5倍至3倍的冲击。" which seems to be a bit jumbled in the translation. It should be something like "By combining the above two inequalities, a matching design window for the tooth profile half angle α and the electromagnet holding force Fhold can be obtained. By adjusting α and Fhold, the system can be reliably locked during normal operation and reliably disengaged under a predetermined impact. An external impact above the predetermined value refers to an impact that causes the instantaneous torque transmitted to the gear ring 240 to exceed 1.5 to 3 times the rated output torque of the drive mechanism 100." But I translated it as accurately as possible based on the original text's structure.In engineering practice, through parameter calculations and experimental verification of different models of refrigerator automatic door opening and closing actuators, an effective and balanced design range for the tooth profile half-angle α is between 2 and 30 degrees. When α < 2°, the tooth profile is close to rectangular, generating a very small radial force. This means that a smaller electromagnet holding force is required to achieve protective disengagement under the same impact torque. Alternatively, for the same electromagnet, an excessively small tooth profile half-angle may lead to insufficient radial force, making reliable disengagement under impact difficult, resulting in a high impact protection threshold and decreased protection sensitivity. When α > 30°, the tooth profile is relatively "sharp," generating a large radial force. The electromagnet holding force required to maintain locking during normal operation is very large, necessitating the use of higher-power, more expensive electromagnets, and increasing energy consumption and heat generation. When 2° ≤ α ≤ 30° (e.g., α is 8 degrees), a better balance between locking reliability and overload protection sensitivity can be achieved within the range of conventional electromagnet selection and impact load estimation.

[0101] Among them, the non-rectangular tooth profile is a trapezoidal tooth profile. The tooth profile half angle is denoted as α, and the value range of the tooth profile half angle α is determined based on the rated output torque of the drive mechanism 100, the estimated external impact torque above a predetermined value, and the rated holding force of the clutch actuator 250.

[0102] The external teeth 242 of the gear ring 240 are specifically designed to engage with the slider 252 of the clutch actuator 250, and do not participate in the power transmission within the planetary gear clutch unit 200. This technical solution embodies the design concept of functional separation, allowing the external teeth 242 to employ a completely different tooth profile from the internal teeth 241. The internal teeth 241 typically have a standard involute tooth profile with a smaller module and higher tooth height to ensure smooth and efficient meshing with the planetary gears and power transmission. The design of the external teeth 242 can be completely independent of the stringent requirements for tooth profile in planetary gear transmissions. The external teeth 242 can employ large-module trapezoidal teeth with a lower tooth height and wider tooth grooves to provide a larger contact area and stronger shear resistance, focusing on bearing and transmitting radial disengagement forces. The tooth profile (such as trapezoidal, triangular, or even sawtooth teeth) and tooth direction (usually spur teeth) of the external gear 242 only need to be designed according to the requirements of clutch and overload protection. Its tooth height, pitch, pressure angle, and other parameters only need to meet the requirements of reliable meshing with the slider, transmission of radial force, and ease of machining, without having to follow the standard gear involute tooth profile or helix angle required by the internal gear 241 that meshes with the planetary gear 220. This allows for the decoupling and optimization of the design of the two functional areas, giving engineers a great deal of freedom to optimize overload protection characteristics without compromising the complex constraints of gear transmission. The machining of both can also be carried out independently; for example, the internal gear can be broached or shaped, while the external gear can be milled or directly formed in a powder metallurgy mold.

[0103] In some embodiments of this application, the radial movement of the slider 252 along the gear ring 240 is the most direct and efficient direction for clutch engagement, with the shortest force flow path and the fastest structural response. The direction of movement of the slider 252 is consistent with the radial direction of the gear ring 240. The slider 252 is typically confined to a linear guide groove along the radial direction of the gear ring. This radial clutch engagement method makes the engagement and disengagement of the slider tooth 254 and the external tooth 242 direct and efficient, with a clear force flow path and no unnecessary motion conversion. The axis of the electromagnet 251 push rod of the clutch actuator 250 is also typically parallel to this radial direction, directly pushing or pulling the slider, resulting in a compact structure and rapid response.

[0104] like Figures 9-11 As shown, the clutch actuator 250 may include a limiting structure 253 for limiting the travel of the slider 252. The limiting structure 253 may be a stop surface or boss provided on the housing or a separately installed limiting pin, ensuring that the slider 252 moves into position and does not overextend or retract. For example, a rigid stop may be provided at the end of the slider 252's travel path to prevent the electromagnet from overshooting and causing the slider to overtravel, ensuring consistent engagement depth, and also preventing excessive retraction of the slider from causing interference with other components.

[0105] In some embodiments of this application, such as Figure 9 As shown, the limiting structure 253 is configured as a limiting groove. The slider 252 is provided with a limiting block 255; the limiting block 255 is installed in the limiting groove (limiting structure 253). The limiting groove includes a first limiting wall 2531 near the external tooth 242 and a second limiting wall 2532 opposite to the first limiting wall 2531 and away from the external tooth 242.

[0106] like Figure 10 As shown, when the toothed portion 254 meshes with the external tooth 242, the limiting block 255 is located within the limiting groove (limiting structure 253) and cooperates with the first limiting wall 2531. The first limiting wall 2531 restricts the limit position of the limiting block 255 to the side closer to the external tooth 242, thereby limiting the limit position of the toothed portion 254 to the external tooth 242. In the above technical solution, the limiting structure 253 is located at the bottom of the slider 252, reducing the space occupied. The limiting structure 253 cooperates with the limiting block 255 on the slider 252 to ensure the stability of the engagement between the toothed portion 254 and the external tooth 242 when the electromagnetic actuator 251 is pushed out.

[0107] When the toothed portion 254 separates from the external tooth 242, the limiting block 255 is located in the limiting groove (limiting structure 253) and cooperates with the second limiting wall 2532; the first limiting wall 2531 restricts the limit position of the limiting block 255 to the side away from the external tooth 242, thereby restricting the limit position of the toothed portion 254 to the side away from the external tooth 242.

[0108] In some embodiments of this application, such as Figure 11 As shown, when the toothed portion 254 separates from the external tooth 242, the limiting block 255 is located within the limiting groove, and the limiting block 255 does not interact with the second limiting wall 2532. Alternatively, when the slider 252 separates from the external tooth 242, there is a first distance between the limiting block 255 and the second limiting wall 2532, and this first distance is greater than 0. This technical solution ensures that when the limiting block 255 moves to its limit position away from the external tooth 242, it does not collide with the second limiting wall 2532, thus preventing damage to the electromagnetic actuator 251 due to incomplete retraction.

[0109] Unlike other similar technologies (or existing technologies), the clutch actuator 250 in this solution is not a standalone, universal electromagnetic clutch, but a dedicated component deeply customized to match the gear ring structure of the planetary gear clutch unit 200. The radial movement of its slider 252, the special shape of its tooth profile 254, and its coupling design with the overload protection function are all designed to serve the specific external teeth of the gear ring. In other similar technologies (or existing technologies), electromagnetic clutches are typically standalone standard components connected to the drive shaft via couplings or gears. Their clutch action is axial or circumferential, and they lack the function of adjustable threshold overload protection through tooth profile half-angle. Therefore, the difference lies in the mechanism: a "customized integrated component" versus a "standardized outsourced component." This solution achieves a more compact layout, lower cost, and seamless integration with the core function (overload protection).

[0110] In some embodiments of this application, the sun gear 212 is typically made of high-strength steel or powder metallurgy material, and its teeth are precision machined to ensure transmission accuracy. The input gear 210 is made of a similar material. In some cost-sensitive applications, the sun gear 212 and the input gear 210 may also be injection molded from high-performance engineering plastics such as POM.

[0111] The sun gear 212 and input gear 210 serve as the power input terminals of the planetary gear clutch unit 200, receiving and transmitting power from the drive mechanism 100, and simultaneously driving the planetary gear system. The sun gear 212 is one of the core components of the planetary gear system, and its number of teeth, together with the number of teeth in the planetary gear 220 and the internal teeth of the gear ring 240, determines the reduction ratio of the unit.

[0112] The positional relationship between the sun gear 212 and the input gear 210 and other parts of the system is very clear. The input gear 210 is located on the upper or outer side of the unit and meshes externally with the output gear 120 of the drive mechanism 100. The sun gear 212 is located on the lower or inner side of the unit and meshes internally with the planetary gear 220. The two are rigidly connected coaxially through an intermediate connecting part (such as an integrally formed bushing or stepped shaft). This component is fitted onto a central shaft fixed to the housing through its central bearing hole, or is supported by bearings on the housing through its own journal, thus enabling it to rotate freely about its axis.

[0113] During dynamic operation, when the drive mechanism 100 is working, power is transmitted to the input gear 210 through the output gear 120, causing the entire sun gear and input gear assembly (210 / 212) to rotate together. The rotation of the sun gear 212 is the driving force for the entire planetary gear system. In automatic mode, the sun gear 212 rotates actively, driving the planetary gears 220. In manual mode, when the planet carrier 230 is reverse-driven by the door, the sun gear 212 usually remains stationary (due to motor resistance), becoming the reference center for the revolution of the planetary gears 220.

[0114] The sun gear 212 and the input gear 210 are coaxially fixed, forming a double gear structure. The diameter of the input gear 210 in the double gear structure is larger than the diameter of the sun gear 212.

[0115] The clutch actuator 250 includes an electromagnetic actuator 251, whose push rod is connected to a slider 252 for driving the slider 252 to move between a first position and a second position. The clutch actuator 250 also includes a reset elastic element that acts on the slider 252, providing an elastic force that tends it toward the second position.

[0116] In some embodiments of this application, the electromagnetic actuator 251 can be a DC push-pull electromagnet. When its coil is energized, the generated electromagnetic force drives the internal iron core (i.e., the push rod) to move linearly. The end of the push rod can be connected to the tail of the slider 252 via a threaded connection, snap-fit, or pin. The reset elastic element is typically a compression spring or a tension spring. For example, a compression spring can be provided, with one end pressing against the housing and the other end pressing against the slider 252. The preload of the spring gives the slider 252 a tendency to move toward the disengagement direction (second position). When the electromagnet is not energized, the spring force firmly holds the slider 252 in the disengagement position, ensuring the system is in manual mode, which is a fail-safe design. When the electromagnet is energized, its electromagnetic force needs to overcome the spring force and push the slider 252 to the engagement position (first position) and hold it there. Therefore, the rated holding force Fhold of an electromagnet actually needs to overcome two forces: first, the spring force (which may vary) and frictional resistance required to move the slider from the disengaged position to the engaged position; and second, the force required to resist the radial component force Frnormal generated during normal operation in the engaged position. Comprehensive calculations are required during the design process.

[0117] In the first position, the slider 252 has at least one toothed portion 254 that meshes with the outer teeth 242 of the gear ring 240. The outer teeth 242 of the gear ring 240 are distributed along its entire circumference, and the toothed portion 254 of the slider 252 has at least one toothed groove that meshes with the outer teeth 242.

[0118] To ensure that the slider 252 can smoothly engage with the rotating gear ring 240 when activating automatic mode from any stopping position (i.e., locking is achieved after the electromagnet actuates regardless of the angle at which the gear ring 240 stops), the outer teeth 242 of the gear ring 240 are typically designed as a full gear ring evenly distributed along the entire circumference. Correspondingly, the toothed portion 254 at the front end of the slider 252 is designed as a "rack segment" with one, two, or more toothed grooves. When the electromagnet pushes the slider out, there are two possible scenarios: Scenario 1: The toothed groove of the slider's toothed portion aligns precisely with the tooth tip of the outer tooth of the gear ring, allowing the slider to smoothly slide into the toothed groove and achieve engagement. Scenario 2: The toothed groove of the slider's toothed portion is misaligned with the tooth tip of the outer tooth of the gear ring, i.e., tooth tip to tooth tip, in which case the slider is blocked by the tooth tip and cannot reach its final position. To solve this problem, the control logic can be designed as follows: First, a brief pulse is given to the electromagnet to push the slider out. If the slider is not fully in place due to the tooth tips not being aligned, the control unit detects this (possibly by detecting the electromagnet current or a dedicated positioning sensor) and controls the drive motor 100 to rotate slightly at a very low speed. The motor rotation drives the sun gear 212 and planetary gear 220, thereby driving the gear ring 240 to rotate slightly. Once the gear ring has rotated a small angle, the tooth grooves and tooth tips align, and under the holding force of the electromagnet or the spring force, the slider will instantly fall into the tooth groove, completing the engagement and locking. This design ensures that the system can smoothly switch from manual mode to automatic locking mode at any initial angle, realizing the "any position engagement / disengagement" function. The number of engaging teeth can be a single tooth or multiple teeth (such as 2-3 teeth). Multiple tooth engagement can improve the reliability and impact resistance of locking, but requires more precise docking control and slightly more axial space.

[0119] In some embodiments of this application, the sun gear 212 and an input gear 210 are coaxially fixed to form a double gear structure. In some embodiments of this application, the sun gear 212 and the input gear 210 can be integrally formed, for example, by using powder metallurgy to form these two gears in one piece, connected by a thin-walled cylinder, thereby ensuring extremely high coaxiality and connection strength. This integrated double gear structure reduces the number of parts, avoids assembly errors, and improves transmission accuracy and reliability. The sun gear 212 and the input gear 210 can also be two independent gears assembled together by a key, spline, or interference fit. Output gear → Input gear: This is the first stage of reduction (or acceleration), with a transmission ratio i1 = Z. 输入齿轮 / Z 输出齿轮 The gear ratio is proportional to their pitch circle diameter. Sun gear → Planetary gear set. This is the second stage of reduction. With the ring gear fixed, the gear ratio of this planetary gear set is i2 = 1 + Z. 齿圈 / Z 太阳轮 >1 (always decelerating). Total gear ratio i 总 =i1×i2, where the planetary carrier is the final output.

[0120] The diameter of the input gear 210 is larger than the diameter of the sun gear 212, i.e., D. 输入齿轮 >D 太阳轮 Equivalent to Z 输入齿轮 >Z 太阳轮 Effect on the first stage (fixed-axis stage): The larger the input gear, the more i1=Z 输入齿轮 / Z 输出齿轮 The larger the value, the greater the first-stage reduction ratio (if the motor gear is a small drive gear). This stage of reduction can share part of the overall reduction ratio, thus allowing the planetary gear system's own reduction ratio (i2=1+Z) to increase. 齿圈 / Z 太阳轮 The size of the sun gear can be designed to be relatively smaller, which allows for a more compact planetary gear system and reduces the dimensions of the ring gear and sun gear. Impact on the second stage (planetary level): Sun gear tooth number Z 太阳轮 The planetary gear transmission ratio is relatively small, i2 = 1 + Z 齿圈 / Z 太阳轮 >1 will increase (because the denominator is small). Overall effect: Both the two-stage transmission ratios i1 and i2 are relatively large → the total transmission ratio i 总 It will be very large. The final output speed is very low, but the torque amplification factor is very large. The sun gear has fewer teeth, which may result in weaker bending strength, but the input gear is large, the first-stage reduction ratio is large, and the torque load on the motor bearings is relatively small.

[0121] In other embodiments, the diameter of the input gear 210 may also be smaller than that of the sun gear 212, i.e., D 输入齿轮 <D 太阳轮 Equivalent to Z 输入齿轮 <Z 太阳轮 Effect on the first stage (fixed-axis stage): The larger the input gear, the more i1=Z 输入齿轮 / Z 输出齿轮 If the output gear is smaller, the first-stage reduction ratio decreases, and it may even increase the speed (if the output gear is larger than the input gear). Effect on the second stage (planetary level): Sun gear tooth count Z 太阳轮 The planetary gearbox transmission ratio is relatively large, i2 = 1 + Z. 齿圈 / Z 太阳轮 >1 will become smaller. Overall effect: Both the two-stage transmission ratios i1 and i2 are smaller → the total transmission ratio i 总 The output speed is relatively high, but the torque amplification factor is relatively small. The sun gear has more teeth and better strength, and the planetary gear set may have a higher load-bearing capacity (because the sun gear tooth root is thick). However, if the reduction ratio of the first stage is too small, the motor may need to output more torque.

[0122] In some embodiments of this application, the planetary carrier 230 may be made of die-cast aluminum alloy or stamped high-strength steel plate to ensure sufficient rigidity and strength to withstand the output torque. Its shape is circular or symmetrical multi-arm disc structure, typically 3-8 mm thick, to achieve lightweight and flattening. The drive arm is a protruding part on top of it, and its shape may be a straight arm or an angled bent arm to accommodate the connection angle with the connecting rod 310.

[0123] The planetary carrier 230 plays a dual role in the planetary gear clutch unit 200, serving as both a power output carrier and a planetary gear support frame. On one hand, it provides the rotation center for the planetary gear 220 via the support shaft 231; on the other hand, its own rotational motion is directly output to the rotary gate mechanism 300, making it the hub connecting the transmission system and the actuator.

[0124] During dynamic operation, in automatic mode, the planetary carrier 230 acts as the driven component, rotating at a lower speed than the sun gear 212 under the influence of the revolution of the planetary gear 220. Its rotation direction is opposite to that of the sun gear 212 during automatic door opening and closing. In manual mode, the planetary carrier 230 becomes the driving component, rotating in the reverse direction driven by the rotary door mechanism 300, which in turn drives the planetary gear 220 to revolve around the sun gear 212.

[0125] In some later embodiments of this application, the planetary carrier 230 is a plate-like structure with a support shaft 231 for mounting at least one planetary gear 220. A portion of the planetary carrier 230 extends outward to form a drive arm for driving the revolving door mechanism 300. There are at least three planetary gears 220, evenly distributed circumferentially along the sun gear 212. The design of the support shaft 231 must ensure sufficient bending strength. The hinge holes on the drive arm are typically fitted with metal bushings to improve wear resistance and ensure hinge accuracy. The length and angle of the drive arm are part of the overall geometric parameters of the revolving door mechanism 300, and their design must be considered in the overall optimization of the revolving door mechanism.

[0126] The plate-shaped planetary carrier 230 helps reduce the overall axial thickness of the unit, achieving a "flattened" design, which is crucial for installation in the limited space at the top of the refrigerator. The planetary carrier 230 is typically formed by stamping sheet metal or injection molding engineering plastics, and is disc-shaped or cross-shaped with a thin profile to achieve flatness. The support shaft 231 can be a protruding post integrally formed with the planetary carrier, or an independent pin pressed into the planetary carrier bore. Three planetary gears 220 are mounted on the three support shafts 231 via needle roller bearings or oil-impregnated bearings, evenly distributed 120 degrees circumferentially. This symmetrical layout ensures even load distribution and smooth operation, while also counteracting radial forces and extending bearing life. The drive arm of the planetary carrier 230 is an arm-like structure extending radially from the edge of the planetary carrier 230 disc, with a through hole at its end for hinged connection to the connecting rod 310 of the door mechanism 300 via a riveted shaft or pin. Sliding bearings or rolling bearings can be installed between the planetary gears 220 and the support shafts 231 on the planetary carrier 230. Sliding bearings can be copper-based or plastic-based bearing sleeves with self-lubricating properties, resulting in lower costs. Rolling bearings, on the other hand, utilize miniature needle roller bearings, which offer low friction, high efficiency, and long lifespan, making them suitable for demanding products. The gear ring 240 is rotatably supported on the housing or bracket of the planetary gear clutch unit 200 via bearings. The outer cylindrical surface or end face of the gear ring 240 has bearing mounting positions, and it is supported at the center of the housing by one or a pair of angular contact bearings, ensuring flexible, smooth, and free rotation in manual mode without jamming.

[0127] Unlike other similar technologies (or existing technologies), the planetary gear clutch unit 200 in this solution creatively integrates the functions of three traditionally separate components—the reducer, clutch, and mechanical overload protection—into a single planetary gear module through the core element of a "gear ring with lockable external teeth." Furthermore, this is achieved through a unique design of "lockable external teeth + non-rectangular tooth profile." In other similar technologies (or existing technologies), these three functions are typically achieved by three independent physical components arranged in series: a set of parallel shaft gear pairs forming the reduction gearbox, an independent electromagnetic clutch for engagement and disengagement, and a friction-type torque limiter or shear pin as a safety clutch providing overload protection. Therefore, the fundamental difference between the two lies in their mechanisms: a "highly integrated single module" versus a "series of separate components." This integrated design eliminates the connection interfaces and redundant structures between components from a mechanistic perspective, which greatly shortens the axial dimension of the transmission chain, significantly reduces the total number of parts, simplifies the assembly process, improves overall reliability, and achieves instantaneous mechanical response for overload protection (without the need for electronic control judgment delay). As a result, this solution brings about the technical effects of extremely compact structure, significantly reduced cost, highly reliable performance, and failure-safe characteristics.

[0128] In some embodiments of this application, the connecting rod 310 of the revolving door mechanism 300 can be formed by stamping and bending of a metal sheet, or by injection molding of a steel rod or high-strength engineering plastic. Its shape is determined based on optimization results, and is usually a curved shape that is not a straight rod, so as to avoid interference with the refrigerator body, door hinge or other components during movement.

[0129] like Figure 2 , Figures 12-14 The diagram shows the state of the power conversion unit 300 when the door is opened to different angles. During the opening process of the door 102 from the closed state, the door 102 opens through a first angle, 90°, and a second angle; wherein the first angle < 90° < the second angle.

[0130] The door mechanism 300, based on its four-bar linkage principle, functions to convert the rotational motion of the planetary carrier 230 into the rotation of the refrigerator door around its fixed hinge axis (point O). Its core lies in achieving specific motion trajectories and force transmission characteristics through the specific proportions of the lengths of the links and the specific positions of the hinge points. For example: the drive arm of the planetary carrier 230 serves as the "drive rod" (AB rod) in the four-bar linkage, with its swing center point A fixed to the refrigerator body; the connecting rod 310 serves as the "connecting rod" (BC rod); the hinge frame 320 fixed to the door body serves as part of the "driven rod" (CO rod); and the hinge center point O of the door body is the fixed hinge point. In other embodiments, the four-bar linkage may have other variations in its configuration, such as changes in the connection points of the drive rod and the connecting rod, but the basic principle remains the same.

[0131] The connection between the revolving door mechanism 300, the planetary gear clutch unit 200, and the refrigerator door is as follows: one end is connected to the end of the drive arm (point B) of the planetary carrier 230 via a hinge (such as a rivet or pin); the other end is connected to point C on the hinge frame 320 fixed to the refrigerator door via another set of hinges. The door rotates around its own fixed hinge axis (point O). Point A (the rotation center of the drive rod) and point O (the hinge center of the door) are both fixed to the refrigerator body, and their relative positions (i.e., the frame rod AO) determine the basic configuration of the mechanism.

[0132] During dynamic operation, when the planetary carrier 230 is driven to reciprocate in automatic mode, it pulls or pushes the hinge point C on the door body via the connecting rod 310, forcing the door body to rotate around point O, thereby opening and closing the door. Throughout the entire movement, the angles (θ1, θ2, θ3) between the connecting rod 310 and the driving rod (AB rod) and the driven rod (CO rod) change continuously, causing the force transmission ratio of the mechanism (i.e., the ratio of driving torque to door resistance torque) to also change continuously. The optimization goal is to make this force transmission ratio as advantageous as possible throughout the entire stroke range, especially at positions where the greatest resistance needs to be overcome (such as the disengagement of the suction aid at the initial opening of the door), thereby minimizing the required driving torque.

[0133] The relative positional relationship between the lengths of each link and each hinge point of the revolving door mechanism 300 is determined based on an optimization algorithm aimed at minimizing the maximum driving torque required by the planetary carrier 230 during the refrigerator door operation. The constraints of the optimization algorithm include: when the door is manually operated, the additional resistance torque introduced by the revolving door mechanism 300 does not exceed a set threshold.

[0134] In some embodiments of this application, the optimization design process is as follows.

[0135] In some embodiments of this application, the cabinet defines a storage space with an access opening, and the door opens or closes the access opening; in the plane where the top wall of the cabinet is located, with the second fixed hinge point (O) as the origin, a straight line parallel to the plane where the access opening is located and passing through the second fixed hinge point (O) is denoted as the X-axis; a straight line passing through the second fixed hinge point (O) and perpendicular to the plane where the access opening is located is denoted as the Y-axis; the door includes a connecting end connected to the cabinet and a free end opposite to the connecting end, and when the door is open, the connecting end rotates around the connecting end; the positive direction of the X-axis is the direction from the free end to the connecting end when the door is closed; the positive direction of the Y-axis is the direction from the plane where the access opening is located to the rear wall of the cabinet; wherein, the Y-coordinate of the plane where the access opening is located is marked as Ym.

[0136] First, establish such Figure 15 The kinematic model of the four-bar linkage shown is described by vector equations, which give us a set of equations for the lengths l0, l1, l2, l3 and the angles θ1, θ2, θ3, θ4: (1).

[0137] Where l1 is the length of the driving rod (AB), l2 is the length of the connecting rod (BC), l3 is the distance from the hinge point C on the driven rod to the door hinge O (length CO), and l0 is the distance between the fixed hinges A and O (length AO). θ 1 is the AB rod and x The angle between the positive axis and the axis; θ 2 is BC rod andx The angle between the positive axis and the axis; θ 3 is the CO rod and x The angle between the positive axis and the axis; θ 4 is the AO rod and x The angle in the positive direction of the axis; θ4 is the fixed angle between the AO rod and the reference coordinate system, introducing the azimuth angle θ. AO The acute angle between the AO rod and the X-axis constitutes the azimuth angle θ of the AO rod. AO， Its relationship with θ4 is θ AO =360°-θ4. Among these parameters, l0, l1, l2, l3, θ AO For design variables.

[0138] Secondly, the static equilibrium equations of the mechanism are established for four operating conditions: automatic opening, automatic closing, manual opening, and manual closing, considering the frictional torque at each hinge point (represented by the friction circle radius ρ). Through derivation, the required torque Tm of the drive rod and the total resistance torque T of the door body can be obtained. f Relationships, such as the driving torque Tm of an automatic door opening mechanism and the door resistance torque T. f Relationship (4).

[0139] (4) This relationship indicates that Tm is a function of the door opening (implied in angles θ1, θ2, θ3) and design variables.

[0140] Then, define the optimization objective: find a set of design variables [l0, l1, l2, l3, θ] over the entire range of motion of the door from closed to maximum opening. AO This minimizes the maximum torque Tmmax of the drive rod required during automatic door opening and closing.

[0141] At the same time, a series of constraints must be met: 1. The drive rod hinge point B does not exceed the refrigerator body boundary (x) during the entire movement. B <0, y B >ym); 2. When manually opening and closing the door, the additional resistance torque increment T'm due to the existence of the revolving door mechanism shall not exceed a set threshold (e.g., 2Nm) to ensure easy manual operation; 3. The maximum opening angle that the door can achieve, θopenmax, is greater than 90 degrees (usually 110-115 degrees). 4. Meet the link length requirements of the four-bar linkage (such as the Grashov criterion) to ensure that a full rotation or a specific oscillation can be completed.

[0142] 5. Numerical optimization methods (such as genetic algorithms and particle swarm optimization) are used to solve the above-mentioned constrained nonlinear optimization problem. Through this optimization, a set of optimal parameters can be obtained. A feasible set of implementation parameters is as follows: l0=216mm, l1=104mm, l2=210mm, l3=100mm, θ AO =33°. This set of parameters reduces the maximum drive torque for automatic door opening from 35.25 Nm in the existing technology to 17.24 Nm, a reduction of 51%.

[0143] The door mechanism 300 includes a connecting rod 310, the first end of which is hinged to the planetary carrier 230, and the second end is hinged to the hinge bracket 320 provided on the refrigerator door. The connecting rod 310 is at least partially bent when the door is closed.

[0144] The curved link 310 is a direct geometrical manifestation of the optimization results. Its purpose is to prevent mechanical interference between the link 310 and the rotation axis area of ​​the door or the side wall of the housing when the door is opened to its maximum angle. The curved shape makes the link more flexible within the motion envelope. Hinges typically use a shaft and sleeve fit. A transition fit can be used between the bushing and the fixed rod to prevent excessive clearance from causing wobbling. At the same time, a small gap can be left between the bushing and the fixed rod to allow for slight vertical displacement of the door due to installation or thermal expansion and contraction, preventing this displacement from causing bending deformation of the link.

[0145] In some embodiments, the curved portion of the link 310 is referred to as the bend; the bend is located near the hinge point (B) between the link and the planetary carrier, relative to the hinge point (C) between the link and the hinge frame. The length of the bent portion is less than half the total length of the connecting rod 310. This technical solution limits the position of the bent portion of the connecting rod to avoid interference with the hinge assembly connecting the door and the housing when the door is opened; on the other hand, it allows the door to be closer to the housing and door structure after opening.

[0146] Unlike other similar technologies (or existing technologies), the revolving door mechanism 300 in this solution is not based on experience or simple spatial layout design, but is the result of rigorous kinematic and static modeling and system optimization with the goal of minimizing driving torque. Its rod length and hinge point position are specific solutions calculated to maximize the mechanism's own force transmission efficiency. In other similar technologies (or existing technologies), the parameter design of revolving door mechanisms often prioritizes spatial avoidance and range of motion, resulting in suboptimal force transmission characteristics, and may even lead to "dead points" or extremely poor force transmission ratios at certain locations, thus necessitating the reliance on an additional top-door mechanism to provide the initial high torque. Therefore, the difference between the two lies in the mechanism of "efficiency optimization design" versus "geometric space design." This solution achieves highly efficient driving from start to finish using only a single revolving door mechanism, fundamentally eliminating the need for a top-door mechanism and solving problems such as structural complexity, uneven switching, and exposed top rods.

[0147] In some embodiments of this application, the angle detection unit may include a high-precision solution and a low-cost solution. In the high-precision solution, the angle detection unit includes a first gear portion 232 disposed on the planetary carrier 230, a second gear 400 meshing with the first gear portion 232, and an angle sensor 500 connected to the rotating shaft of the second gear 400.

[0148] In some embodiments of this application, the first gear portion 232 may be a tooth arc (incomplete gear) on the edge of the planet carrier 230, or it may be a complete pinion mounted coaxially with the planet carrier 230. The number of teeth of the second gear 400 is much less than the number of teeth (or equivalent number of teeth) of the first gear portion 232, forming a speed-increasing transmission pair. This allows the shaft of the angle sensor 500 to rotate multiple times when the planet carrier rotates a certain angle (e.g., 90 degrees), thereby utilizing the sensor's limited measurement range (e.g., 0-360 degrees) to accurately measure the large-angle oscillation of the planet carrier. The angle sensor 500 may be an analog output potentiometer, or a digital output photoelectric encoder or magnetic encoder.

[0149] In the low-cost solution, the angle detection unit includes a first position sensor, a second position sensor, and a trigger that moves with the planetary carrier 230. The trigger is configured to activate the first and second position sensors respectively when the door reaches the closed position and the maximum open position. The first and second position sensors can be microswitches or reed switches. The trigger of the planetary carrier 230 can be a rocker arm 603. The first and second position sensors can be fixed to the refrigerator body.

[0150] In some embodiments of this application, the first position sensor can directly utilize the refrigerator's existing door switch (used to control the interior lighting), which reduces cost and complexity. The second position sensor is a new addition. The trigger is a lever 603 or protrusion extending from the planetary carrier 230. The arc curve (604) at the end of the lever 603 is designed to allow it to smoothly pass through the sensor's trigger arm in a rolling or sliding manner when the second position sensor is triggered, reducing impact and wear and ensuring the stability of the trigger signal.

[0151] The angle detection unit plays a crucial role in the system by monitoring the opening and closing angle of the door in real time or determining a specific position (fully closed, fully open). The angle or position signal provided by the angle detection unit is the foundation for the control unit to achieve precise position control, speed adjustment, obstacle detection, and status recording. For example, in a high-precision solution, a large-angle rotation of the planetary carrier is amplified into a small-angle rotation of the angle sensor shaft through gear transmission, improving measurement resolution; in a low-cost solution, simple position detection is achieved through two switches.

[0152] The connection between the angle detection unit and the planetary gear clutch unit 200 depends on the specific design. In a high-precision design, the first gear 232 is directly mounted on the planetary carrier 230 (coaxially or via an extension arm) and meshes with the second gear 400. The shaft of the second gear 400 is connected to the shaft of the angle sensor 500. In a low-cost design, the first and second position sensors are fixedly mounted on the refrigerator body, while the trigger unit is located on the planetary carrier 230 and moves with it.

[0153] During dynamic operation, for the high-precision solution, any rotation of the planetary carrier 230 is transmitted to the angle sensor 500 through the gear pair. The sensor continuously outputs a voltage, pulse, or digital signal proportional to the angle. For the low-cost solution, when the door is closed, the trigger presses or approaches the first position sensor, causing it to output a "door closed" signal. When the door is opened to the preset maximum angle, a specific part of the trigger (such as the arc curve 604 at the end) triggers the second position sensor, causing it to output a "door open" signal. In the intermediate position, neither sensor (the first position sensor nor the second position sensor) is triggered.

[0154] Unlike other similar technologies (or existing technologies), this solution offers two differentiated implementation schemes (high-precision continuous detection and low-cost two-point detection), which can be flexibly adapted to refrigerator product lines of different grades and costs, giving the technical solution a wider market applicability. In contrast, other similar technologies (or existing technologies) typically only employ one method, resulting in either higher costs or more basic functionality. Therefore, the difference between the two lies in their "configuration flexibility," thereby enhancing the productization flexibility and market competitiveness of this invention.

[0155] In some embodiments of this application, the control unit can be a separate printed circuit board (PCB) or integrated into the refrigerator's main control board. Its core can be a microcontroller (MCU), responsible for receiving instructions, processing sensor signals, and outputting motor drive signals and electromagnet control signals.

[0156] The control unit acts as the "command center" of the system. Based on user input (button, voice, network) and feedback from the angle detection unit, it coordinates the timing of the drive mechanism 100 and the clutch actuator 250 to achieve complex automatic control logic, safety protection, and anomaly handling. For example, when the control unit executes the automatic door opening program, it first powers on the clutch actuator 250 to lock it, then starts the drive mechanism 100 to rotate in a preset direction, while simultaneously monitoring the angle sensor signal. When the angle reaches the set value, the motor stops and the clutch is released.

[0157] The control unit is connected to the motor driver of the drive mechanism 100, the electromagnet drive circuit of the clutch actuator 250, and the angle detection unit (angle sensor 500 or position sensor 601 / 602) via wires or flexible circuits for power supply and signal communication.

[0158] During dynamic operation, the logic of the control unit determines the system behavior.

[0159] In some embodiments of this application, the control unit can be configured to energize the electromagnetic actuator 251 of the clutch actuator 250 only during brief periods when the drive mechanism 100 needs to output power to drive the door, keeping it in the locked position; at other times (such as when the door is stationary in the open or closed state), the electromagnetic actuator 251 is de-energized to save energy and reduce heat generation, during which time the system is in manual mode. The clutch actuator 250 may include a return spring, which ensures that the slider 252 reliably returns to the disengaged position when the electromagnet is de-energized, providing a fail-safe design.

[0160] In some embodiments of this application, if the angle detection unit detects obstruction of movement (such as abnormal angle change) during automatic operation, the control unit immediately cuts off the power supply to the electromagnet 251 and stops the motor, thereby achieving active obstruction protection.

[0161] Unlike other similar technologies (or existing technologies), this solution's control logic is deeply coupled with a unique mechanical structure (planetary gear clutch unit), enabling advanced functions such as "clutch engagement at any position" and "interrupted transmission resumption." Furthermore, it forms a dual safety system of "electronic active protection + mechanical passive protection" with mechanical overload protection. In contrast, other similar technologies (or existing technologies) may have relatively simple control logic, or limitations in the mechanical structure (such as the clutch only engaging at specific positions) prevent such flexible and intelligent control. Therefore, the difference lies in the collaborative innovation of control strategy and mechanical structure, resulting in a superior user experience and system safety.

[0162] In this application, "suction aid" refers to a common device on refrigerator doors used to achieve automatic door closing. It typically consists of a hook on the door and a spring-loaded roller or groove on the refrigerator body. When the door closes to a near-closed position (e.g., the last 3-10 degrees), the hook contacts the roller and compresses the spring, storing elastic potential energy. After the door passes a certain point, the spring releases energy, assisting in quickly pulling the door to the fully closed position. This device generates an initial holding force that needs to be overcome during the initial stage of automatic door opening.

[0163] In this application, "rotating beam" refers to a reversible, sealing beam located between the two refrigerator doors in a side-by-side refrigerator. When one door is closed, the rotating beam is in a first position, sealing the gap between the door and the central beam; when the door is opened, the rotating beam can be flipped to a second position by a linkage mechanism or manually. The flipping process requires overcoming a certain amount of friction and possible magnetic attraction.

[0164] The refrigerator door is the refrigerator compartment door of a side-by-side refrigerator, and the door is equipped with a suction device that generates a self-closing force and / or a rotating beam that can be flipped.

[0165] The above technical solutions precisely define the application targets of this solution, which typically exhibit high initial resistance. The suction aid provides the "self-closing force" in the final stage of door closure, but becomes the "initial holding force" that must be overcome first during automatic door opening. The rotating beam needs to flip from the first sealed position to the second position at the start of automatic door opening; this flipping action requires additional torque. These two factors are the main reasons why traditional solutions require a top-mounted door mechanism. The optimized rotating door mechanism of this solution is designed to efficiently overcome these specific resistances.

[0166] In some embodiments of this application, in conjunction with the overall system operation, the user says "open the refrigerator" via voice, and the control unit receives the command. The control unit first checks the current state of the door (e.g., via the first position sensor) to confirm that the door is closed. Then, the control unit sends an energizing command to the electromagnetic actuator 251 of the clutch actuator 250, pushing the slider 252 to extend. Since the outer teeth 242 of the gear ring 240 are full-circumferential teeth and are currently stationary, the toothed portion 254 of the slider 252 may abut against the tooth tip. Subsequently, the control unit starts the drive mechanism 100, the motor micro-moves, and drives the gear ring 240 to rotate slightly until the slider 252 falls into the tooth groove, completing reliable engagement and locking. After locking, the control unit controls the drive mechanism 100 to run at full speed in the opening direction or according to a preset speed curve. After the power is reduced and increased in torque by the planetary gear clutch unit 200, it drives the optimized revolving door mechanism 300 to work. The revolving door mechanism 300 efficiently converts the rotational motion into door swing sufficient to overcome the holding force of the suction aid and the overturning force of the rotating beam with a small input torque, so that the door opens smoothly. The angle detection unit provides real-time feedback on the door angle. When the preset opening angle (e.g., 90 degrees) is reached, the control unit stops the drive mechanism 100 and disconnects the power supply to the clutch actuator 250, and the system enters manual mode, allowing the user to manually adjust the door angle. During the opening process, if the user blocks the door with their hand, the control unit detects the abnormality through the angle sensor and immediately executes the obstruction protection logic, switching to manual mode. If the door is violently impacted during automatic operation, the mechanical overload protection mechanism of the planetary gear clutch unit 200 will activate instantly, physically disengaging to protect the gears. The automatic closing process is similar, but in the opposite direction. When the door closes to its final angle, the suction aid intervenes to assist in closing. The control unit can adjust the motor closing logic accordingly or release the clutch early, allowing the suction aid to complete the final stage of suction, thus improving closing smoothness and energy efficiency.

[0167] The entire system operates collaboratively across its components under various working conditions. In standby mode, both the drive mechanism 100 and the clutch actuator 250 are de-energized, the planetary gear clutch unit 200 is in a manually free state, and the revolving door mechanism 300 can be manually operated along with the door. Upon automatic startup, the clutch actuator 250 first attempts to lock, followed by the drive mechanism 100 starting to provide power; the timing of these actions ensures smooth engagement. During automatic operation, the drive mechanism 100 continues to operate, the clutch actuator 250 remains locked, the angle detection unit provides continuous feedback, and the control unit monitors and makes judgments in real time. When encountering an obstacle or reaching the endpoint, the control unit coordinates the timing of the drive mechanism 100 stopping and the clutch actuator 250 releasing. In the event of an accidental impact, the mechanical overload protection activates instantly, independent of the electronic control system. This multi-layered, multi-mechanism collaboration ensures the system's reliability, safety, and user experience under various operating conditions.

[0168] Within the technical framework of an automatic refrigerator door opening and closing system, its core functional modules typically consist of a drive mechanism that provides power, a transmission mechanism that reduces speed, increases torque, and distributes power, and a rotary door actuator that ultimately performs the door opening and closing action. Existing technical solutions, to address the self-closing force of the refrigerator door and the initial tilting torque of the tilting beam, generally employ a series collaboration between an independent door-lifting mechanism and a rotary door mechanism. This approach has inherent technical bottlenecks: the door-lifting mechanism is responsible for providing a large lifting force in the initial stage to overcome the static resistance of the door, and then needs to smoothly transfer the driving task to the rotary door mechanism to complete the subsequent large-angle opening and closing. This collaborative process leads to a complex system structure, numerous components, exposed door rods affecting aesthetics, and a series of defects such as unstable movement and swaying at the action switching point between the two mechanisms. The prevailing thinking in existing technology is that a separate, dedicated linear actuator (door-lifting mechanism) for providing a large initial thrust must solve the problem of a large initial opening torque, treating "providing a large initial torque" and "completing the entire movement" as functions that must be undertaken by two physically separate mechanisms.

[0169] However, this mindset fails to fundamentally examine the mechanical transmission efficiency of the revolving door actuator itself. The linkage parameter design of traditional revolving door mechanisms is often based on experience or simple spatial avoidance, without systematic optimization with drive efficiency as the core objective. This results in suboptimal force transmission characteristics throughout the entire movement, especially during the initial opening stage where maximum resistance must be overcome. The required input torque at the drive end is excessive, thus "forcing" the system to introduce an additional door-pushing mechanism. The mechanism of this technical problem lies in the fact that traditional design methods fail to treat the revolving door mechanism as an optimizable mechanical system and fail to explore its potential for providing "small torque input, large torque output" through parameter reconfiguration.

[0170] To overcome the aforementioned technical challenges, this solution abandons the additive approach of "adding mechanisms to supplement torque" and instead adopts a reconstructive problem-solving mechanism of "optimizing the core mechanism to improve its own efficiency." Specifically, the following technical methods are employed: First, the revolving door actuator is abstracted into a standard four-bar linkage model, and a complete set of kinematic and static equations is established for its entire opening and closing cycle (including automatic and manual opening and closing). Based on this, an optimization function is constructed with the core objective of minimizing the input torque required by the drive lever. Subsequently, a series of practical engineering constraints are introduced, such as ensuring the drive hinge point does not exceed the housing area, that the increment of manual operating force is lower than a set threshold, and that the maximum opening and closing angle of the door meets usage requirements. Finally, numerical optimization algorithms (such as intelligent optimization algorithms) are used to systematically optimize the length of each link and the relative position parameters of each hinge point in the four-bar linkage, thereby obtaining a set of optimal geometric parameters that significantly reduce the required torque of the drive lever throughout its entire stroke, especially at high-resistance points.

[0171] Through the aforementioned methods, this solution enables the optimized single revolving door mechanism to reliably overcome the full-stroke motion resistance of the door (including the maximum initial static resistance) with a relatively small input torque at the drive end, without the need for external jacking assistance, thus achieving the fundamental goal of eliminating the need for a separate door-jacking mechanism. Therefore, it achieves a series of technical benefits, including significantly simplified structure, reduced number of parts, significantly lower manufacturing costs, complete elimination of uneven movement at mechanism switching points, and exposure of the door jacking rod.

[0172] Furthermore, the core mechanism of this solution lies in the systematic parameter optimization of the actuator based on a mechanical model. This breaks the technical inertia of traditional technology, which states that "actuator design only serves the motion trajectory and spatial layout." This reconstructs the design principles of the actuator, elevating it from a passive "motion realization unit" to an active "force flow optimization unit." Ultimately, this achieves a simplified yet highly efficient design that replaces external functional patches by tapping into the inherent potential of the mechanism.

[0173] After successfully optimizing the actuator and reducing its torque requirements, this solution incorporates an integrated innovation in the transmission mechanism to further match low-torque motors and achieve safe and flexible switching between manual and automatic modes. In traditional solutions, functions such as deceleration, clutch engagement, and overload protection are often implemented by separate gear sets, electromagnetic clutches, torque limiters, and other components, resulting in a loose structure, long axial dimensions, high cost, and response delays in electronically controlled overload protection. This solution breaks away from the conventional thinking of "separate functions corresponding to separate components," adopting a problem-solving mechanism that integrates multiple functions into a single planetary gear module.

[0174] The specific technical approach adopted is as follows: a planetary gear system is used as the basic transmission unit, with the sun gear as input and the planet carrier as output, forming a speed reduction and torque amplification path. The key innovation lies in designing the gear ring as a dual-function component with both internal and external teeth: the internal teeth mesh with the planetary gears to participate in transmission; the external teeth are specifically used to mesh with a linear slider driven by an electromagnetic actuator, realizing the locking (automatic mode) and releasing (manual mode) of the gear ring. More importantly, the tooth profile of the external teeth at the meshing point with the slider is designed as a non-rectangular tooth profile with a specific tooth profile half-angle (such as trapezoidal teeth). By precisely designing this tooth profile half-angle and matching it with the holding force of the electromagnetic actuator, a mechanical overload protection threshold can be set: when the door is subjected to an unexpected and violent impact during automatic operation, the resulting impact torque is converted into a huge radial disengagement force through the tooth profile surface. This force will exceed the electromagnetic holding force, forcibly pushing the slider away, allowing the gear ring to rotate freely instantaneously, thereby cutting off the power transmission chain and achieving purely mechanical instantaneous overload protection.

[0175] Therefore, this solution achieves three major functions simultaneously—speed reduction and torque increase, mode switching, and mechanical overload protection—through a highly integrated planetary gear clutch unit, resulting in an extremely compact structure, small axial dimensions, fast response speed (no delay in mechanical overload protection), and high reliability.

[0176] Furthermore, the "controllable radial separation based on tooth profile half-angle design" mechanism adopted in this solution breaks the technical inertia of traditional clutches that "the locking tooth profile pursues reliable self-locking (such as rectangular teeth), and the protection mechanism is set separately." This reconstructs the functional definition of the clutch, enabling it to simultaneously bear the seemingly contradictory states of "reliably transmitting normal torque" and "automatically disengaging under excessive torque" on the same set of tooth surface meshing pairs. Ultimately, it achieves the passive, built-in, and instantaneous realization of safety protection functions.

[0177] Therefore, this solution, by reconstructing the design paradigm of the actuator and the functional integration method of the transmission mechanism, and through the two core technical means of "actuator parameter system optimization" and "multi-functional integration of planetary gears," solves the problems of complex structure, uneven operation, susceptibility to damage from accidental impacts, and high cost in automatic door opening and closing systems. Furthermore, this solution overcomes two long-standing technical biases in the home appliance industry regarding automatic door design: "high initial resistance must be solved by adding an external door-mounting mechanism" and "safety protection must rely on sensors and electronic control logic."

[0178] In this application, "planetary gear clutch unit 200" refers to a composite transmission device that integrates planetary gear reduction function, mode clutch function, and mechanical overload protection function. Its core feature is that it includes a gear ring with specially designed external teeth, which are used to cooperate with the clutch actuator. The tooth profile design enables the unit to automatically disengage under specific conditions.

[0179] In this application, "gear ring 240" refers to the ring gear component in a planetary gear system, which has internal teeth 241 and external teeth 242. The internal teeth are used to mesh with the planetary gears to participate in power transmission and deceleration; the external teeth are dedicated to cooperating with the slider of the clutch actuator to realize the locking or releasing of the gear ring, and its tooth profile design is independent of the transmission tooth profile of the internal teeth. In this application, "non-rectangular tooth profile" refers to the tooth profile of a gear or similar meshing component, whose tooth flank working surface is not parallel to the central axis, but forms a certain angle, such as trapezoidal teeth, triangular teeth, etc. When such a tooth profile transmits torque during meshing, it generates a normal force perpendicular to the tooth surface, which can be decomposed into tangential and radial components.

[0180] In this application, "tooth profile angle" refers to the angle formed between the working surfaces of two tooth sides in a non-rectangular tooth profile (especially a trapezoidal tooth profile). The inclination angle of a single tooth surface is usually described by the tooth profile half angle α, which is half of the tooth profile angle.

[0181] In this application, "revolving door mechanism 300" refers to a linkage mechanism that converts rotational motion into rotation of the refrigerator door about its hinge axis. Specifically, in this application, it refers to a planar four-bar linkage optimized by kinematics and mechanics, the optimization objective of which is to minimize the input torque required at the drive end while ensuring the range of motion and manual operating force requirements.

[0182] In this application, "door-pushing mechanism" refers to a common type of independent actuator in the prior art that applies a pushing force to the refrigerator door through a linear pushing motion during the initial stage of automatic door opening, in order to overcome significant initial resistance (such as door seal suction or suction booster gripping force). It typically consists of components such as a motor, cam, and push rod, and is separate from the door-turning mechanism that drives the door to complete subsequent large-angle movements.

[0183] This application provides a scenario for the automatic opening and closing of a refrigerator door. Users can remotely trigger the automatic opening or closing of the door via voice commands, touchscreen buttons, or an application. Upon receiving the command, the refrigerator control system drives the device to automatically open the refrigerator door to a preset angle (e.g., 90 degrees) for easy access to items, or automatically close the door from any opening angle. During automatic operation, if the user manually obstructs the door's movement, the device intelligently switches to manual mode; if the door is subjected to an unexpected and violent impact, the device's built-in mechanical protection mechanism will activate instantly to prevent damage to the internal gears.

[0184] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

[0185] For ease of explanation, the above description has been provided in conjunction with specific embodiments. However, the above exemplary discussion is not intended to be exhaustive or to limit the embodiments to the specific forms disclosed above. Various modifications and variations can be obtained based on the above teachings. The selection and description of the above embodiments are for the purpose of better explaining the principles and practical applications, thereby enabling those skilled in the art to better utilize the described embodiments and various different variations of embodiments suitable for specific use considerations.

Claims

1. An automatic door opening and closing device for a refrigerator, It includes a drive mechanism (100), a transmission mechanism, and a rotary door mechanism (300). The transmission mechanism is used to transmit the power output by the drive mechanism (100) to the door mechanism (300), and the door mechanism (300) is used to connect to and drive the refrigerator door. Its features are, The transmission mechanism includes a planetary gear clutch unit (200), which comprises: The sun gear (212) is connected to the output end of the drive mechanism (100); At least one planetary gear (220) meshes with the sun gear (212); The planetary carrier (230) is rotatably connected to the at least one planetary gear (220) and serves as the drive input of the rotary door mechanism (300); The gear ring (240) has internal teeth (241) that mesh with the at least one planetary gear (220) and external teeth (242) disposed radially outward therefrom. The clutch actuator (250) has a slider (252) that can be actuated to move in a straight line, the slider (252) having a toothed portion (254) that engages with the external teeth (242). The slider (252) has a first position and a second position: In the first position, the toothed portion (254) engages with the external tooth (242) to restrict the rotation of the toothed ring (240); In the second position, the toothed portion (254) disengages from the external tooth (242), and the toothed ring (240) can rotate freely; The tooth profile surface that meshes with the toothed portion (254) is a non-rectangular tooth profile with a tooth angle. The holding force provided by the clutch actuator (250) to actuate the slider (252) to remain in the first position is denoted as F1. When the drive mechanism (100) normally drives the rotary door mechanism (300), the component force in the disengagement direction generated by the non-rectangular tooth profile and acting on the slider (252) is denoted as F2. When the door body driven by the revolving door mechanism (300) is subjected to an external impact exceeding a predetermined value, the component force in the disengagement direction generated by the non-rectangular tooth profile and acting on the slider (252) is denoted as F3. Where F2≤F1≤F3.

2. The automatic door opening and closing device for a refrigerator according to claim 1, characterized in that, The non-rectangular tooth profile is a trapezoidal tooth profile.

3. The automatic door opening and closing device for a refrigerator according to claim 2, characterized in that, The tooth profile half angle of the non-rectangular tooth profile is denoted as α. The range of the tooth profile half angle α is determined based on the rated output torque of the drive mechanism (100), the estimated external impact torque above the predetermined value, and the rated holding force of the clutch actuator (250).

4. The automatic door opening and closing device for a refrigerator according to claim 3, characterized in that, The value of the tooth profile half-angle α ranges from 2 degrees to 30 degrees.

5. The automatic door opening and closing device for a refrigerator according to claim 1, characterized in that, The clutch actuator (250) includes an electromagnetic actuator (251), the push rod of which is connected to the slider (252) for driving the slider (252) to move between the first position and the second position.

6. The automatic door opening and closing device for a refrigerator according to claim 5, characterized in that, When the slider (252) is in the first position, the number of meshing teeth between its toothed portion (254) and the outer teeth (242) of the toothed ring (240) is at least one.

7. The automatic door opening and closing device for a refrigerator according to claim 6, characterized in that, The outer teeth (242) of the toothed ring (240) are distributed along its entire circumference, and the toothed portion (254) of the slider (252) has at least one tooth that meshes with the groove of the outer teeth (242).

8. The automatic door opening and closing device for a refrigerator according to claim 1, characterized in that, The outer teeth (242) of the gear ring (240) are specifically designed to engage with the slider (252) of the clutch actuator (250) and do not participate in the power transmission inside the planetary gear clutch unit (200).

9. The automatic door opening and closing device for a refrigerator according to claim 1, characterized in that, The direction of movement of the slider (252) is consistent with the radial direction of the toothed ring (240).

10. The automatic door opening and closing device for a refrigerator according to claim 1, characterized in that, The clutch actuator (250) also includes a limiting structure for limiting the travel of the slider (252).

11. The automatic door opening and closing device for a refrigerator according to claim 1, characterized in that, The sun gear (212) and the input gear (210) are coaxially fixed to form a double gear structure.

12. The automatic door opening and closing device for a refrigerator according to claim 11, characterized in that, The diameter of the input gear (210) in the double gear structure is larger than the diameter of the sun gear (212).

13. The refrigerator automatic door opening and closing device according to claim 1, characterized in that, The planetary carrier (230) is a plate-like structure with a support shaft (231) for mounting at least one of the planetary gears (220). A portion of the planetary carrier (230) extends outward to form a drive arm for driving the rotary door mechanism (300).

14. The automatic door opening and closing device for a refrigerator according to claim 1, characterized in that, The number of the at least one planetary gear (220) is three, and they are evenly distributed along the circumference of the sun gear (212).

15. The automatic door opening and closing device for a refrigerator according to claim 1, characterized in that, The revolving door mechanism (300) includes a connecting rod (310), the first end of which is hinged to the planetary carrier (230), and the second end is hinged to the hinge bracket (320) provided on the refrigerator door body, and the connecting rod (310) is at least partially bent.

16. The automatic door opening and closing device for a refrigerator according to claim 1, characterized in that, The curved portion of the connecting rod (310) is referred to as the curved portion; the curved portion is located near the hinge point between the connecting rod (310) and the planetary carrier (230) relative to the hinge point between the connecting rod (310) and the hinge frame (320). The length of the bent portion is less than half the total length of the connecting rod (310).

17. The automatic door opening and closing device for a refrigerator according to claim 1, characterized in that, It also includes an angle detection unit configured to detect the rotation angle of the planetary carrier (230).

18. The automatic door opening and closing device for a refrigerator according to claim 17, characterized in that, The angle detection unit includes a first gear set on the planetary carrier (230), a second gear (400) meshing with the first gear set, and an angle sensor (500) connected to the shaft of the second gear (400).

19. The automatic door opening and closing device for a refrigerator according to claim 17, characterized in that, The angle detection unit includes a first position sensor and a second position sensor fixed on the refrigerator body, and a trigger part that moves with the planetary frame (230). The trigger part is configured to trigger the first position sensor and the second position sensor respectively when the door reaches the closed position and the maximum open position.

20. The automatic door opening and closing device for a refrigerator according to claim 5, characterized in that, The clutch actuator (250) is configured to actuate the slider (252) to the first position only when the drive mechanism (100) needs to output power to drive the door; and to hold or release the slider (252) to the second position when the drive mechanism (100) does not output power.

21. The automatic door opening and closing device for a refrigerator according to claim 1, characterized in that, The holding force of the clutch actuator (250) actuating the slider (252) is determined based on the torque transmitted to the gear ring (240) by the drive mechanism (100) under rated load, the first radial force value calculated from the tooth profile half angle of the non-rectangular tooth profile, and a safety factor is added.

22. The automatic door opening and closing device for a refrigerator according to claim 1, characterized in that, The external impact exceeding the predetermined value refers to an impact that causes the instantaneous torque transmitted to the gear ring (240) to exceed the rated output torque of the drive mechanism (100) by 1.5 to 3 times.

23. The automatic door opening and closing device for a refrigerator according to claim 1, characterized in that, The relative positional relationship between the length of each link and each hinge point of the rotary door mechanism (300) is determined based on an optimization algorithm aimed at minimizing the maximum driving torque required by the planetary carrier (230) during the automatic opening and closing of the refrigerator door.

24. The automatic door opening and closing device for a refrigerator according to claim 23, characterized in that, The constraints of the optimization algorithm include: when the door is manually operated, the additional resistance torque introduced by the door mechanism (300) is between 0.5 Nm and 4 Nm.

25. The automatic door opening and closing device for a refrigerator according to claim 1, characterized in that, The refrigerator door is the refrigerator compartment door of a side-by-side refrigerator, and the door is equipped with a suction device that generates a self-closing force and / or a rotatable beam that can be flipped.

26. The automatic door opening and closing device for a refrigerator according to claim 5, characterized in that, The clutch actuator (250) further includes a reset elastic element that acts on the slider (252) to provide an elastic force that moves it toward the second position.

27. The automatic door opening and closing device for a refrigerator according to claim 1, characterized in that, A sliding bearing or a rolling bearing is provided between the planetary gear (220) and the support shaft (231) on the planetary carrier (230).

28. The automatic door opening and closing device for a refrigerator according to claim 1, characterized in that, The gear ring (240) is rotatably supported on the housing or bracket of the planetary gear clutch unit (200) by bearings.

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