Refrigerator

Abstract

The application provides a refrigerator automatic door opening and closing device, which comprises a box body, a door body rotatably connected with the box body, a driving unit arranged on the box body, and a power conversion unit connected between the driving unit and the door body; the power conversion unit is a planar linkage system formed by a first connecting rod, a second connecting rod, a third connecting rod and a virtual fixed rod; in the planar linkage system, the length and position configuration relationship between the first connecting rod, the second connecting rod, the third connecting rod and the virtual fixed rod and the angle of the azimuth angle satisfy the following condition: in the whole process of driving the door body from the fully closed state to an opening angle of more than 90 degrees, the maximum driving torque of the driving unit acting on the first connecting rod is greater than the total resistance torque acting on the second fixed hinge point generated by the self-closing force and the resistance of the turnover beam when the door body is in the fully closed state; the refrigerator automatic door opening and closing device of the application realizes the effect of completing the full stroke automatic door opening by a single driving source and simplifies the structure.

Description

Technical Field

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

[0002] Within the technological framework of refrigerator products, the automatic door opening and closing function module is typically composed of a drive mechanism that provides power, a transmission and execution mechanism that transmits and converts motion, and a clutch and protection mechanism that enables mode switching and safety protection.

[0003] Current mainstream technologies have developed a deeply ingrained technological mindset when dealing with the unique characteristics of refrigerator doors—specifically, the significant initial resistance torque generated by the sealing force and the flip-up beam mechanism when closed. This mindset holds that a single traditional rotary door mechanism (typically a four-bar linkage) cannot output a sufficiently large torque to overcome the aforementioned resistance during the initial opening phase due to its inherent force transmission characteristics. Therefore, the industry-standard solution is to introduce a separate "door-pushing mechanism." This mechanism typically employs a linear pushing motion, applying a large thrust at the initial opening stage to open the door at a small angle to overcome the initial sealing force and the flip-up beam resistance; afterwards, it switches to the rotary door mechanism to complete the subsequent large-angle opening action. This composite solution of "door-pushing mechanism + rotary door mechanism" constitutes the mainstream paradigm of current technology.

[0004] However, this technological paradigm has given rise to a series of interconnected technical bottlenecks: First, the transition point between the two mechanisms is difficult to achieve smoothly and seamlessly, which may cause jerks or sudden speed changes in the door movement during the transition, affecting the smoothness of movement and user experience. Second, to avoid interference or conflict between the two drive mechanisms during movement, complex transition structures (such as drive grooves with spring buffers) are often required in their transmission chains. The cam structure commonly found on refrigerator doors, used to generate self-closing force, can exert additional thrust on the door at specific locations. This thrust may cause abnormal movement of the springs within the transition structure, further exacerbating the instability of movement. Third, to obtain sufficient ejection force, the push rod of the door-opening mechanism usually needs to extend from the side of the cabinet. This not only disrupts the overall appearance of the cabinet during ejection but also requires a large clearance during retraction, affecting aesthetics. Finally, two mechanisms inevitably lead to an increase in the number of parts and structural complexity, raising manufacturing costs and assembly difficulty. These bottlenecks collectively constitute obstacles to the pursuit of high performance and high integration in existing technological solutions.

[0005] With the development of smart homes, the market has put forward higher requirements for the integration and performance of this functional module: it is expected to achieve smooth and reliable automatic door opening and closing action throughout the entire process to improve the user experience, and it is also required to have a compact overall structure and simplified parts to reduce manufacturing costs and facilitate placement in the limited internal space of the refrigerator.

[0006] In view of the above, this application is hereby submitted. Summary of the Invention

[0007] This application provides a refrigerator whose power conversion unit adopts a single planar linkage system with specific parameter configuration, which realizes the effect of automatic door opening of the whole stroke by a single drive source and simplifies the structure.

[0008] In a first aspect, an automatic door opening and closing device for a refrigerator is provided, comprising: The box has a door on its front side, which is rotatably connected to the box via a hinge system; A drive unit, mounted on the housing, is used to output rotational power; A power conversion unit is connected between the output end of the drive unit and the door body, and is used to convert the rotational power into an action that drives the door body to swing around its rotation axis. The power conversion unit is a planar linkage system consisting of a first link, a second link, a third link, and a virtual fixed link, all hinged together. Wherein, the first end of the first connecting rod is hinged to the first fixed hinge point on the box body, and its second end is hinged to the first end of the second connecting rod at the first movable hinge point. The second end of the second link is hinged to the first end of the third link at the second connection point; The second end of the third link is hinged to a second fixed hinge point on the door body, and the second fixed hinge point is located on the rotation axis of the door body; The output end of the drive unit is connected to the first connecting rod transmission, and is used to drive the first connecting rod to swing around the first fixed hinge point; The line connecting the first fixed hinge point and the second fixed hinge point forms a virtual fixed rod; The acute angle between the virtual fixing rod and the plane containing the door in its fully closed state constitutes the azimuth angle θ of the virtual fixing rod. AO ; In the planar linkage system, the lengths of the first link, the second link, the third link, and the virtual fixed link, and the azimuth angle θ AO The length and positional arrangement relationships among the five angles satisfy: During the entire process of the door being driven open from a fully closed state to an opening angle of more than 90°, the maximum driving torque of the driving unit acting on the first link is greater than the total resistance torque generated by the self-closing force and the resistance of the flip beam that the door experiences in the fully closed state and acts on the second fixed hinge point.

[0009] The above technical solution breaks away from the conventional thinking that "a single linkage mechanism cannot provide adequate torque when the door is closed, and an additional door-mounting mechanism must be relied upon for activation" in existing technologies. This application cleverly utilizes a four-bar linkage with a specific length ratio, whose force transmission characteristics are configured to have a high force transmission ratio when the door is closed. Using this single-plane linkage system with specific parameter configuration, the large resistance torque formed by the door's self-closing force and the reversing force of the tilting beam can be effectively overcome with a relatively small input driving torque throughout the entire door opening stroke, especially in the initial stage. This achieves the effect of automatic door opening with a single drive source while eliminating the need for an independent door-mounting mechanism and its switching mechanism, and simplifies the structure.

[0010] In some embodiments, the length l1 of the first link, the length l2 of the second link, the length l3 of the third link, the length l0 of the virtual fixed rod, and the azimuth angle θ AO The matching relationship between them is denoted as the length and position configuration relationship; The length and positional configuration relationship satisfies: 20°≤θ AO ≤60°, 155mm≤l0≤300mm, 50mm≤l1≤115mm, 180mm≤l2≤300mm, 75mm≤l3≤200mm.

[0011] The above technical solution, by limiting the length of each rod within the verified parameter range, ensures that the planar linkage system can stably achieve the aforementioned high force transmission ratio characteristic, solves the problem of substandard performance caused by the inability to simultaneously meet various constraints, and provides a better selection basis for the reliable implementation of the device.

[0012] In some embodiments, the length and position configuration relationship also satisfies that: when the door is manually operated, the incremental operating torque added to the door due to the presence of the planar linkage system is denoted as Tm', where 0.5Nm≤Tm'≤4Nm.

[0013] The above technical solutions, by imposing an upper limit constraint on the additional torque for manual operation, ensure the ease of operation of the device in manual mode, solve the problem of deteriorated manual operation experience, and achieve the effect of improving user experience.

[0014] When the increase in operating torque is greater than 4Nm, the increase in operating torque will cause the manual torque required to open the door of a refrigerator equipped with automatic door opening and closing function to exceed 4Nm in manual mode, making it difficult to open the door and affecting the user experience.

[0015] When the operating torque increment is less than 0.5 Nm, the operating torque increment is too small, which will affect the length l1 of the first link, the length l2 of the second link, the length l3 of the third link, the length l0 of the virtual fixed rod, and the azimuth angle θ. AO The optimized data increases the maximum driving force Tm(max), making it difficult to effectively overcome the large resistance torque formed by the door's self-closing force and the reversing force of the flip beam with a relatively small input driving torque in the initial stage of door opening.

[0016] In some embodiments, the enclosure defines a storage space with an access opening, and the door opens or closes the access opening. In the plane containing the top wall of the enclosure, with the second fixed hinge point as the origin, a straight line parallel to the plane containing the access opening and passing through the second fixed hinge point is denoted as the X-axis; a straight line passing through the second fixed hinge point and perpendicular to the plane containing the access opening is denoted as the Y-axis. The door includes a connecting end connected to the housing and a free end opposite to the connecting end. When the door is open, the free end rotates around the connecting end. When the door is closed, the direction of the free end pointing to the connecting end is denoted as the positive direction of the X-axis. The direction of the plane where the access opening is located pointing to the rear wall of the housing is denoted as the positive direction of the Y-axis, forming a two-dimensional coordinate system XOY. The Y-coordinate of the plane where the access opening is located is ym; When the door is in a fully closed state, the x-coordinate value of the first movable hinge point is less than zero, and its y-coordinate value is greater than ym.

[0017] The above technical solution, by limiting the position of the first movable hinge point to a specific area inside the box when the door is closed, ensures that the linkage system does not interfere with the internal structure of the box during the entire opening and closing process, thus solving the problem of collision between the moving mechanism and the box.

[0018] In some embodiments, the hinge point between the third link and the door is located on the rotation axis of the door and near the edge of the door away from the box when it is in the fully closed state.

[0019] The above technical solution increases the lever arm when opening the door by setting the hinge point between the third link and the door body on the side of the door body away from the box body. This allows the drive unit to more effectively overcome the resistance torque when the door body is closed, thus solving the problem of insufficient starting torque.

[0020] In some embodiments, the drive unit includes a motor and a reduction gear mechanism, the output end of which is connected to the first linkage.

[0021] The above technical solutions, by employing a motor and a reduction gear transmission mechanism, provide sufficient output torque and controllable speed, thus solving the problems of insufficient torque or excessive speed that may occur with direct drive.

[0022] In some embodiments, the reduction transmission mechanism is a planetary gear reducer, the planetary structure of which forms the output end of the drive unit and is connected to the first connecting rod.

[0023] The above technical solution, by using a planetary gear reducer and taking the planet carrier as the output end, achieves the advantages of compact structure, large reduction ratio, smooth transmission, and concentricity between the output shaft and the input shaft, thus solving the problems of large space occupation and inconvenient layout of traditional multi-stage gear reducers.

[0024] In some embodiments, the refrigerator automatic door opening and closing device further includes a clutch mechanism, which is disposed between the motor and the reduction transmission mechanism or integrated inside the reduction transmission mechanism, for switching between automatic mode and manual mode.

[0025] The above technical solution, by incorporating a clutch mechanism, enables reliable switching between automatic and manual operation modes, solving the problem of the motor and reduction transmission mechanism becoming resistance during manual operation, thus improving the flexibility of use.

[0026] In some embodiments, the speed reduction transmission mechanism includes a rotating component; the rotating component is provided with mating teeth; The clutch mechanism is an electromagnetic clutch mechanism, which includes a locking element that can be driven by electromagnetic force. The locking element has a locking position and an unlocking position that engage or disengage with mating teeth.

[0027] The above technical solutions, by employing an electromagnetic clutch mechanism, achieve rapid, accurate, and electrically controllable mode switching, thus solving the problems of inconvenient operation or slow response of mechanical clutches.

[0028] In some embodiments, the mating surfaces of the mating teeth and the locking member are respectively provided with mutually cooperating inclined teeth; when the two are engaged, the inclined teeth cooperate with each other to prevent the rotating component from rotating relative to each other in the circumferential direction, this state is the automatic mode; when the torque borne by the rotating component exceeds a set threshold, the radial separation force generated by the mating surface can overcome the electromagnetic force and cause the locking member to disengage from the mating teeth, this state is the manual mode.

[0029] The above technical solution, by designing the joint surface as a sloping structure, can achieve a purely mechanical instantaneous disengagement protection in the event of overload (such as human impact on the door), thus solving the problem of slow response and potential damage to transmission components when relying solely on electronic control detection, thereby improving the reliability and safety of the system.

[0030] Secondly, a refrigerator is provided, comprising: an automatic door opening and closing device as described above.

[0031] The above technical solution, by applying an automatic door opening and closing device with an optimized linkage system to the refrigerator, enables the refrigerator to achieve advantages such as simplified structure, smooth and reliable door opening and closing, and no exposed top-out mechanism. It solves the problems of complex structure, high cost, or poor aesthetics of existing refrigerators with automatic door opening and closing functions. Attached Figure Description

[0032] Figure 1 An exemplary schematic diagram of the overall structure of a refrigerator according to some embodiments is shown; Figure 2 An exemplary schematic diagram of a refrigerator having an automatic door opening and closing device according to some embodiments is shown; Figure 3 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 4 An exemplary schematic diagram of a partial structure of a refrigerator automatic door opening and closing device according to some embodiments is shown; Figure 5 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 6 An exemplary cross-sectional view of a refrigerator automatic door opening and closing device according to some embodiments is shown; 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 exploded view of a refrigerator automatic door opening and closing device according to some embodiments is shown as an example; Figure 9 An exemplary schematic diagram of a refrigerator door according to some embodiments is shown when it is opened to a first angle; Figure 10 An exemplary schematic diagram of a refrigerator door opened to 90° according to some embodiments is shown; Figure 11 An exemplary schematic diagram of a refrigerator door opened to a second angle according to some embodiments is shown; Figure 12 An exemplary simplified kinematic model of the power conversion unit for an automatic door opening and closing process according to some embodiments is shown; Figure 13 An exemplary force model of the automatic door opening process of the power conversion unit according to some embodiments is shown; Figure 14An exemplary force model of the automatic door closing process of the power conversion unit according to some embodiments is shown; Figure 15 An exemplary force model of the power conversion unit during manual door opening process according to some embodiments is shown; Figure 16 An exemplary force model of the power conversion unit during manual door closing process according to some embodiments is shown; Figure 17 An exemplary flowchart of design variable optimization calculation according to some embodiments is shown.

[0033] The components include: a housing 1; a door 2; a hinge system 3; a hinge frame 320; a power conversion unit 300; a first fixed hinge point A; a second fixed hinge point O; a first movable hinge point B; a second connection point C; a first connecting rod AB; a second connecting rod BC; a third connecting rod CO; a virtual fixed rod AO; a drive unit 100; a motor 110; a reduction transmission mechanism 120; a planetary carrier 230; a planetary gear 220; a sun gear 212; a gear ring 240; an input gear 210; a clutch mechanism 200; an electromagnet 251; a locking element 252; a locking tooth 254; a mating tooth 242; an angle detection unit 500; a first gear section 232; and a detection gear 400. Detailed Implementation

[0034] 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.

[0035] like Figures 1-11 As shown, the automatic door opening and closing device of the refrigerator includes: a cabinet 1, a door 2, a drive unit 100, and a power conversion unit 300. Optionally, it also includes a clutch mechanism 200, a control unit, and an angle detection unit. The cooperative relationship between the units is as follows: the drive unit 100 provides rotational power (based on commands from the control unit), which is transmitted to the power conversion unit 300 after being controllably switched on and off by the clutch mechanism 200; the power conversion unit 300 converts the rotational motion into a planar linkage swing, thereby pulling or pushing the door 2 to rotate relative to the cabinet 1, realizing the opening and closing of the door; the angle detection unit monitors the angular position of the door or related transmission components in real time and feeds the signal back to the control unit, forming a closed-loop control. The control unit coordinates the entire action sequence and achieves precise control based on the feedback from the angle detection unit 500.

[0036] In some embodiments of this application, the cabinet 1 can be the outer shell structure of the refrigerator's cold storage compartment or freezer compartment, typically made of metal sheet (such as steel sheet) or engineering plastic, with sufficient structural strength to support the installation of the door, hinges, and automatic door opening / closing device. It constitutes the main frame of the refrigerator and the outer boundary of the storage space.

[0037] Based on its function of accommodating storage space, the housing 1 serves as both the installation foundation and the spatial carrier within the system. For example, the front opening edge of the housing 1 typically features a reinforcing structure for mounting the hinge system 3, and the side walls or top have pre-reserved cavities or mounting brackets for mounting the drive unit 100 and its transmission components. In other embodiments, a dedicated mounting base plate can also be provided on the inner side wall of the housing 1 for centrally fixing components such as the drive unit 100 and the clutch mechanism 200.

[0038] The housing 1 and the door 2 are rotatably connected by a hinge system 3. For example, one end of the hinge system 3 is fixed to the reinforcing structure of the housing 1 by screws or welding, and the other end is similarly fixed to the side edge of the door 2. In other embodiments, the hinge system 3 is a dual-axis hinge, where the first pivot (main axis) allows the door 2 to swing relative to the housing 1, and the second pivot allows for minor translation of the door 2 within a certain range to avoid interference. The second fixed hinge point O is typically located on the axis of the first pivot (main axis).

[0039] During the dynamic operation of the door opening and closing mechanism, the housing 1 serves as a fixed reference frame, with the first fixed hinge point A and the second fixed hinge point O remaining stationary relative to the housing 1. The door 2 rotates around the second fixed hinge point O, and the links of the power conversion unit 300 move within the space defined by the wall of the housing 1, ensuring no interference. In other embodiments, the inner wall of the housing 1 may be equipped with guide rails or limiting blocks to guide or restrict the movement trajectory of certain links (such as the second link BC).

[0040] In this embodiment, the front side of the cabinet 1 is provided with a door 2, which is rotatably connected to the cabinet 1 via a hinge system 3. In other embodiments, the cabinet 1 may be one of the compartments of a multi-door refrigerator.

[0041] In some embodiments of this application, the enclosure defines a storage space with an access opening, and a door opens or closes the access opening. For example... Figure 3 As shown, in the plane containing the top wall of the box, with the second fixed hinge point O as the origin, the straight line parallel to the plane containing the access opening and passing through the second fixed hinge point O is denoted as the X-axis; the straight line passing through the second fixed hinge point O and perpendicular to the plane containing the access opening is denoted as the Y-axis. The door includes a connecting end connected to the housing and a free end opposite to the connecting end. When the door is open, the free 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 housing. A two-dimensional coordinate system XOY is formed. The Y-coordinate of the plane containing the access opening is ym; When the door 2 is in a fully closed state, the x-coordinate value of the first movable hinge point B is less than zero, and its y-coordinate value is greater than ym.

[0042] The above settings limit the position of the first movable hinge point B to a specific area inside the box when the door is closed, thereby ensuring that the linkage system does not interfere with the internal structure of the box during the entire opening and closing process, and solving the problem of collision between the moving mechanism and the box.

[0043] In some embodiments of this application, the first movable hinge point B is located in the area projected onto the top wall of the cabinet in the coordinate system XOY, so as to ensure that the range of motion of the first movable hinge point B in the coordinate system XOY is limited to the area defined by the top wall of the cabinet, and to avoid the range of motion of the first movable hinge point B in the coordinate system XOY exceeding the top wall of the cabinet and requiring additional space beyond the top wall of the cabinet, so that no additional space is needed to place the refrigerator.

[0044] In some embodiments of this application, the door 2 can be the door of a refrigerator compartment or freezer compartment, typically consisting of a door shell, an inner liner, an insulation layer, and a door seal. The door shell serves as an exterior component, the inner liner forms part of the storage space, and the door seal is used to tightly fit against the opening edge of the compartment 1 when closed to achieve a seal.

[0045] In some embodiments of this application, the door 2, based on its function of sealing storage space and opening access opening, serves as a driven execution terminal in the system. Example: The door 2 is provided with a hinge bracket 320 for mounting a third link CO. The hinge bracket 320 needs to have sufficient strength to withstand the tensile or pushing forces from the link.

[0046] In some embodiments of this application, the door 2 and the power conversion unit 300 are connected by a third link CO and a hinge frame 320 to achieve power transmission. This connection point is the second connection point C. The door 2 and the housing 1 are rotatably connected by a hinge system 3.

[0047] During the automatic opening and closing operation, the door 2 is in a first state (e.g., closed), where it is pressed tightly against the housing 1 by the self-closing force and the resistance of the tilting beam. In the second state (e.g., opening), the drive unit 100 applies a torque to the door 2 through the power conversion unit 300 to overcome the resistance, causing the door 2 to begin rotating around the hinge axis (second fixed hinge point O). During opening, the angle of the door 2 gradually increases, and the hinge frame 320 on it causes point C of the door 2 to move accordingly. During automatic closing, the above movement process is reversed.

[0048] In this embodiment, the second end of the third link CO is hinged to the second fixed hinge point O on the door body 2, and the second fixed hinge point O is located on the rotation axis of the door body 2. In other embodiments, the hinge frame 320 may be a metal bracket fixed to the inner liner of the door body, which has an outwardly protruding hinge shaft or bushing.

[0049] The hinge point (O) between the third link CO and the door 2 is located on the rotation axis of the door 2, near the edge of the door 2 away from the cabinet 1 when it is fully closed. For example, in a side-by-side refrigerator, the rotation axis of the left door is located on its left side, and the rotation axis of the right door is located on its right side. Positioning the hinge point O near the edge of the door's rotation axis allows for a relatively short length l3 of the third link CO and a large lever arm (the distance from point O to the door's center of gravity or resistance center), which is beneficial for obtaining a larger driving torque.

[0050] In this embodiment, the hinge system is a dual-axis hinge, and the second fixed hinge point O is located on the main axis of the dual-axis hinge. In other embodiments, if a single-axis hinge is used, then point O is the axis of that single axis.

[0051] Unlike other similar technologies (such as automatic doors with exposed push rods), the outer side of the door body 2 in this application (the side that mates with the housing) does not require a recess or receiving mechanism for mates with the push rod, nor does it require an opening for the push rod to pass through. In other similar technologies, the door body typically requires a recess or bevel to mate with the end of the push rod. Therefore, there is a significant difference in the structural integrity of the two, resulting in a simpler manufacturing process, a more complete and aesthetically pleasing appearance, and no issues of heat leakage or aesthetics caused by gaps in the push rod mating.

[0052] In some embodiments of this application, such as Figures 2-8 As shown, the drive unit 100 can be a combination including a motor 110 and a reduction gear mechanism 120. The motor 110 can be a brushed DC motor, a brushless DC motor, or a stepper motor, providing the initial rotational power. The reduction gear mechanism 120 is used to reduce the motor's output speed while increasing the output torque.

[0053] The drive unit 100, based on its function of providing controllable rotational power, acts as a power source in the system. For example, the output torque and speed of the drive unit 100 are calculated and matched to overcome the resistance torque of the door 2 under the most unfavorable operating conditions through the optimized power conversion unit 300, and to meet the door opening and closing speed requirements.

[0054] The drive unit 100 is fixedly connected to the housing 1 by bolts, clips, or brackets. Its output end is connected to the first link AB of the power conversion unit 300 via transmission, or indirectly via the clutch mechanism 200. It is electrically connected to the control unit via wires to receive start / stop, steering, and speed control commands.

[0055] During the dynamic operation of the automatic door opening and closing mechanism, the drive unit 100 has a first state (standby state), in which the motor 110 is not powered, and the output shaft is stationary or disconnected by the clutch mechanism 200. The drive unit 100 has a second state (automatic door opening start), in which the control unit sends commands to the motor 110 and the clutch mechanism 200, the clutch mechanism 200 engages, and the motor 110 starts running in a specific direction (such as the door opening direction) and with a specific current (or PWM duty cycle), outputting torque through the reduction transmission mechanism 120. During operation, the control unit may adjust the input voltage or PWM duty cycle of the motor 110 based on the angle feedback signal to achieve speed control (such as acceleration at start, constant speed operation, and deceleration before reaching the destination). The drive unit 100 has a third state (automatic door closing start), in which the motor 110 runs in reverse. The drive unit 100 has a fourth state (manual mode). In the fourth state, the clutch mechanism 200 is disengaged, the motor 110 can be de-energized or in a free state, and the movement of the door 2 will not drag the motor 110 to rotate (or the clutch mechanism is designed to allow it to idle).

[0056] The drive unit 100 includes a motor 110 and a reduction transmission mechanism 120. The output end of the reduction transmission mechanism 120 is connected to the first connecting rod AB via a transmission. For example, the output shaft of the motor 110 is connected to the input gear / worm gear of the reduction transmission mechanism 120 via a coupling or directly. The final output shaft of the reduction transmission mechanism 120 (such as a planetary carrier shaft or a final stage gear shaft) is fixed to the rod body of the first connecting rod AB near the first fixed hinge point A via a key connection, tight fit, or flange connection, so that the rotation center of the output shaft coincides with point A. The rotation of the output shaft directly drives the first connecting rod AB to swing around the first fixed hinge point A.

[0057] The reduction transmission mechanism 120 is a planetary gear reducer, with its planet carrier 230 forming the output end of the drive unit 100 and being connected to the first connecting rod AB via a transmission. For example, the planetary gear reducer includes a sun gear 212, multiple planet gears 220, a planet carrier 230, and a ring gear 240. The output of the motor 110 drives the sun gear 212 via the input gear 210. When the ring gear 240 is fixed, power is output from the planet carrier 230; the planet carrier 230 is directly or via a connector fixed to the first connecting rod AB. The planetary gear reducer can provide a large reduction ratio and a compact structure, with its output shaft (planet carrier) coaxial with the input shaft (sun gear), facilitating layout.

[0058] Among them, such as Figures 2-8 As shown, the refrigerator's automatic door opening and closing device also includes a clutch mechanism 200. The clutch mechanism 200 is located between the motor 110 and the reduction transmission mechanism 120, or integrated inside the reduction transmission mechanism 120, and is used to switch between automatic mode and manual mode. The clutch mechanism includes a metal gear, an engineering plastic housing, an electromagnet coil, and magnetic conductive materials.

[0059] The clutch mechanism 200, based on its function of controlling the opening and closing of the power transmission path, acts as a "switch" for switching between automatic and manual modes in the system. For example: in automatic mode, the clutch mechanism 200 reliably transmits the power from the drive unit 100 to the power conversion unit 300; in manual mode, the clutch mechanism 200 disconnects this transmission path, allowing the user to freely operate the door manually while preventing the motor from being dragged backward.

[0060] In some embodiments of this application, the clutch mechanism 200 is integrated inside the reduction gear transmission mechanism 120. The clutch mechanism 200 and the reduction gear transmission mechanism 120 are fused into a planetary gear clutch mechanism. The gear ring 240 of the planetary gear clutch mechanism is not always fixed, but can be selectively locked or released by a locking member 252 driven by an electromagnet 251. When the locking teeth 254 of the locking member 252 mesh with the mating teeth 242 on the outer periphery of the gear ring 240, the gear ring 240 is fixed, the planetary gear system works in a deceleration state, and the planet carrier 230 outputs power (automatic mode). When the locking member 252 retracts, the gear ring 240 is free. At this time, when the door body 2 is manually rotated to drive the planet carrier 230 to rotate, the planetary gear 220 will revolve around the stationary sun gear 212 and drive the gear ring 240 to rotate freely. The output shaft of the motor 110 does not rotate with it or can rotate freely (manual mode).

[0061] The clutch mechanism 200 is an electromagnetic clutch mechanism, including a locking member 252 that can be driven by electromagnetic force. The locking member 252 has a locking position and an unlocking position that engage or disengage with mating teeth 242 on a rotating component (such as a gear ring 240) of the reduction transmission mechanism 120. For example, when the electromagnet 251 is energized, its push rod extends, pushing the locking member 252 (such as a slider) to move along a straight line or arc, causing the locking teeth 254 at the front end of the locking member 252 to insert between the mating teeth 242 (such as external teeth) on the outer periphery of the rotating component (such as a gear ring 240) to engage with the mating teeth 242, thus locking. When the electromagnet 251 is de-energized, the spring force or the restoring force of the electromagnet 251 pulls the locking member 252 back, disengaging the locking teeth 254 from the mating teeth 242, thus unlocking.

[0062] The mating surfaces of the mating teeth 242 and the locking member 252 are respectively provided with mutually cooperating inclined teeth. When the two are engaged, the inclined teeth cooperate to prevent the rotating component (such as the gear ring 240) from rotating relative to each other in the circumference. This allows the radial separation force generated by the mating surfaces to overcome the electromagnetic force and disengage the locking member 252 from the mating teeth 242 when the torque on the rotating component (such as the gear ring 240) exceeds a set threshold in automatic mode. For example, the mating teeth 242 of the gear ring 240 and the locking teeth 254 of the locking member 252 are trapezoidal teeth, and their mating surfaces (tooth flanks) have a tooth profile half angle α with the radial direction.

[0063] During normal transmission, the torque T borne by the gear ring 240 is transmitted through the mating surface, generating a radial component force Fr=T*tan(α) / r on the locking element 252, attempting to push it away, where r is the radius of the meshing point. If α is too small (tooth profile is close to rectangular), the radial separation force is small, and the overload protection sensitivity is low; if α is too large (tooth profile is sharp), the radial separation force during normal transmission is also large, requiring a larger electromagnet to maintain the lock, which is uneconomical.

[0064] Therefore, it is necessary to comprehensively determine the value of α based on the maximum torque Tnormal during normal transmission, the selected electromagnetic holding force Fhold, and the radius r of the meshing point. The design should meet the following requirements: during normal operation, the holding force (or spring pre-tightening force) of the electromagnetic solenoid 251 should be slightly greater than the maximum Frnormal during normal transmission, where Frnormal = Tnormal * tan(α) / r < Fhold. When an abnormal overload occurs (such as a violent human impact on the door body), the instantaneous torque Timpact increases sharply, resulting in a radial component force Frimpact greater than the holding force of the electromagnetic solenoid, where Frimpact = Timpact * tan(α) / r > Fhold. Here, Timpact is the set torque threshold for overload protection triggering. Thus, the locking member 252 is forcibly pushed open to achieve mechanical overload protection and disconnect the power transmission. By reasonably selecting α, reliable overload protection can be achieved. Exemplary: If r = 30 mm, Tnormalmax = 5 Nm, and it is desired to have protection when Timpact = 20 Nm, with the electromagnetic holding force Fhold = 50 N. Then it can be calculated that during normal operation, it is required that tan(α) < (Fhold * r) / Tnormal = (50 * 0.03) / 5 = 0.3, that is, α < 16.7°; during overload, it is required that tan(α) > (Fhold * r) / Timpact = (50 * 0.03) / 20 = 0.075, that is, α > 4.3°. Therefore, α can be selected between 4.3° and 16.7°, for example, taking α = 10°.

[0065] The system allows switching between manual and automatic modes at any door opening / closing angle. For example, when the door is half-open (e.g., 60°), the user triggers automatic closing. At this time, because the gear ring 240 is in a free state, its mating teeth 242 and the locking teeth 254 of the locking element 252 may not be aligned (tooth tip to tooth tip). The control process is as follows: 1) The electromagnet 251 is energized, and the locking element 252 is pushed out. Due to the misalignment, the locking teeth 254 may be pressing against the tooth tip of the mating teeth 242, without engagement, and the gear ring can still rotate freely. 2) The motor 110 is started to rotate in the closing direction. The motor drives the sun gear 212 to rotate, which in turn drives the planetary gears 220, attempting to drive the planetary carrier 230 to rotate in the closing direction. However, because the gear ring 240 is free at this time, the entire planetary gear system is in a differential state, the motor idles or rotates slowly, and the planetary carrier 230 may not rotate temporarily or rotate slowly. 3) During motor rotation, planetary gear 220 drives ring gear 240 to slowly idle. When the ring gear 240 rotates until the groove of its mating tooth 242 aligns with the locking tooth 254 of the locking element 252, the locking element 252 instantly falls into the groove under the thrust of the electromagnet, completing the engagement and locking the ring gear 240. 4) Once the ring gear 240 is locked, the planetary gear system immediately enters the fixed-axis reduction transmission state, and the motor torque is effectively output through the planetary carrier 230, starting the automatic door closing action. This process achieves a "seamless" mode engagement at any position.

[0066] During dynamic operation, the clutch mechanism 200 has a first state (automatic mode preparation): when the control unit issues an automatic door opening / closing command, the electromagnet 251 is energized first. The push rod of the electromagnet 251 extends, pushing the locking member 252 to move along a straight line or guide groove, so that the locking tooth 254 at the front end of the locking member 252 engages with the mating tooth 242 on the outer periphery of the gear ring 240. At this time, the gear ring 240 is fixed and cannot rotate.

[0067] The clutch mechanism 200 has a second state (automatic mode operation): the motor 110 starts, and the power is transmitted to the planet carrier 230 through the sun gear 212 and planet gear 220. Since the ring gear 240 is fixed, the planet carrier 230 outputs torque at a reduced speed.

[0068] The clutch mechanism 200 has a third state (manual mode): when the electromagnet 251 is de-energized, the locking element 252 retracts under the action of the return spring or the electromagnet's own return force, and the locking tooth 254 disengages from the mating tooth 242. At this time, the gear ring 240 is in a free state. When the user manually opens or closes the door, the door movement drives the planetary carrier 230 to rotate through the linkage system, and the planetary gear 220 revolves around the basically fixed sun gear 212 (because the motor has internal resistance or slight electromagnetic braking), while simultaneously driving the gear ring 240 to rotate freely. Power is not transmitted back to the motor, achieving the convenience of manual operation.

[0069] The clutch mechanism 200 has a fourth state (overload protection): In automatic mode, if the door is subjected to a violent external impact, a huge abnormal torque Timpact is instantaneously generated on the planetary carrier 230 and the gear ring 240. This torque is converted into a separation force Fr=Timpact*tan(α) / r by the engagement slope of the locking tooth 254 and the mating tooth 242, which attempts to radially push the locking member 252. If this instantaneous separation force Fr exceeds the holding force (attraction force) of the electromagnet 251 on the locking member 252 in the current energized state, the locking member 252 will be forcibly pushed away, causing the gear ring 240 to instantly disengage and become free. The transmission chain is mechanically cut off, thereby protecting the gears and other precision components from damage.

[0070] Unlike other similar technologies (such as those employing independent clutches, reducers, and motors arranged in series), this application creatively integrates the clutch function with a planetary gear reducer, directly determining the transmission mode (reduction / differential) based on the gear ring's state (fixed / free), and integrating the overload protection function into the same meshing interface through a special tooth profile design. This application highly integrates reduction, clutch, and even overload protection functions into a single planetary gear clutch mechanism, significantly reducing the number of parts and axial dimensions. In other similar technologies, the clutch, reducer, and overload protector are typically implemented as three independent components connected in series, resulting in long axial dimensions, numerous parts, high cost, loose structure, and large space occupation. Therefore, existing similar technologies differ fundamentally from this application in terms of integration and space utilization. The clutch mechanism 200 of this application integrates three major functions in a very small space, resulting in a more compact structure and greatly optimizing the overall size and cost of the automatic door opening / closing actuator, making it particularly suitable for installation environments with limited space on the refrigerator door or top of the refrigerator cabinet.

[0071] The power conversion unit 300 is the core motion conversion mechanism of the refrigerator's automatic door opening and closing device, such as... Figure 2 , Figures 9-11 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.

[0072] Specifically, the power conversion unit 300 is a planar four-bar linkage consisting of a first link AB, a second link BC, a third link CO, and a virtual fixed link AO, all hinged together. The structural material can be metal, such as steel or aluminum alloy, to provide sufficient strength and rigidity, or it can be a high-strength engineering plastic. The shape is primarily rod-shaped, with the second link BC having a specific bending shape. In other embodiments, the links can also be composite structures, such as a metal core encased in plastic.

[0073] Wherein, the first fixed hinge point A is a fixed rotation center fixed on the box body 1, and the second fixed hinge point O is a fixed rotation center fixed on both the box body 1 and the door body 2. During the opening and closing of the door, the first fixed hinge point A and the second fixed hinge point O are relatively stationary, and the line connecting the first fixed hinge point A and the second fixed hinge point O forms a virtual fixed rod AO.

[0074] The power conversion unit 300, based on the function of converting the rotational motion output by the drive unit 100 into the swinging motion of the door 2, plays a key role in the system in motion form conversion and force / torque amplification. For example: the drive unit 100 drives the first link AB to reciprocate around point A, and through the transmission of the second link BC, pushes the third link CO and the door 2 to reciprocate around point O (the second fixed hinge point O), thus realizing the opening and closing of the door. In this way, the swinging motion of the drive rod (AB) at a small angle is amplified into a large-angle rotation of the door 2 exceeding 90°, while its geometric configuration is optimized to achieve effective force amplification. In other embodiments, this unit can also be regarded as a mechanical amplifier with variable transmission bit characteristics.

[0075] The connection between the power conversion unit 300 and the drive unit 100 is as follows: the first end of the first link AB of the power conversion unit 300 is fixedly connected to the output end of the drive unit 100 (or the output end after passing through the clutch mechanism) at the first fixed hinge point A, so that the rotation center of the output shaft coincides with point A, and the rotation of the output shaft is directly converted into the oscillation of the first link AB around point A.

[0076] The second end of the first link AB is hinged to the first end of the second link BC at point B.

[0077] The connection between the power conversion unit 300 and the door body 2 is as follows: the second end of the second link BC is hinged to the first end of the third link CO (the hinge frame 320 on the door body 2) at the second connection point C. The second end of the third link CO is hinged to the door body 2 at point O. Point O coincides with the hinge axis of the door body 2.

[0078] The power conversion unit 300 is associated with the housing 1 as follows: the first fixed hinge point A is fixed to the top of the housing 1 or to an internal support, forming one of the fixed reference bases for the entire linkage system. In other embodiments, the first link AB can also be connected to the output end of the drive unit 100 via an intermediate transition piece.

[0079] During the dynamic operation of the automatic door opening and closing mechanism, the power conversion unit 300 has a first state (door closed), at which time each linkage is in a specific initial position configuration. At this time, the first movable hinge point B is located on the side of the first fixed hinge point A closest to the side wall of the housing 1. The acute angle between the virtual fixed rod AO and the plane (X-axis) where the door 2 is in the fully closed state constitutes the azimuth angle θ of the virtual fixed rod AO. AO Among them, the length of the first link AB (l1), the length of the second link BC (l2), the length of the third link CO (l3), the length of the virtual fixed link AO (l0), and the azimuth angle θ AO The geometric relationships together determine the force transmission ratio of the mechanism in the closed position.

[0080] The power conversion unit 300 has a second state (door opening process). In this state, the drive unit 100 drives the first link AB to swing in the door opening direction (the drive unit 100 drives the first link AB to swing counterclockwise (taking the left door as an example)). The first link AB drives the second link BC through point B, and the second link BC then drives the third link CO through point C. Since point O of the third link CO is constrained on the rotation axis of the door body 2, this driving force forces the door body 2 to begin rotating around point O, thus opening the door. Throughout the entire door opening stroke, the spatial positions of points B and C change continuously, causing key angles such as the angle between the second link BC and the third link CO (θ3-θ2) and the angle between the first link AB and the second link BC (θ2-θ1) to continuously change. This makes the instantaneous force transmission ratio (output torque / input torque) of the mechanism a function of the door opening angle. This application optimizes the design to maintain a high function value throughout the entire door opening stroke, especially in the initial stage when the resistance torque is greatest, thereby minimizing the input torque required by the drive unit 100. Where θ1 is the angle between rod AB and the positive X-axis; θ2 is the angle between rod BC and the positive X-axis; and θ3 is the angle between rod CO and the positive X-axis.

[0081] The power conversion unit 300 has a third state (door open to its maximum angle), where each link reaches another extreme configuration. At this point, the bent portion of the second link BC precisely avoids the door hinge area, preventing interference. The automatic closing process is the reverse of the above process; the drive unit 100 drives the first link AB to swing in the opposite direction, pushing the door 2 to close through the linkage system. The closing process is the reverse of the above motion.

[0082] The power conversion unit 300 comprises a planar linkage system consisting of a first link AB, a second link BC, a third link CO, and a virtual fixed link AO, all hinged together. These hinges are all revolute joints, allowing relative rotation between the links within the plane of motion. In other embodiments, each link can be a straight rod or a rod with a specific curved shape to accommodate space avoidance requirements.

[0083] In this configuration, the first end of the first connecting rod AB is hinged to the first fixed hinge point A on the housing 1, and its second end is hinged to the first movable hinge point B of the second connecting rod BC. Each hinge point can be implemented using a pin-bearing coupling or a pin-sleeve coupling. Alternatively, oil-impregnated bearings or miniature needle roller bearings can be installed at hinge points A and B to reduce friction.

[0084] In this embodiment, the second end of the second link BC is hinged to the first end of the third link CO at the second connection point C. In other embodiments, to reduce weight, the links may be made of aluminum alloy or engineering plastic, and reinforcing ribs may be provided in key stress-bearing parts.

[0085] In this design, the second end of the third link CO is hinged to the second fixed hinge point O on the door body 2, which is located on the rotation axis of the door body 2. This hinge must ensure that only the torque rotating about point O is transmitted, without restricting small displacements of the door body 2 in other directions (allowing for slight radial float to accommodate small translations caused by the dual-axis hinge or manufacturing tolerances). Therefore, a bushing with clearance or a spherical bearing can be used at the hinge point.

[0086] In this context, the line connecting the first fixed hinge point A and the second fixed hinge point O forms a virtual fixed rod AO. This is an imaginary rod with fixed length and direction, representing the geometric constraint between the two fixed points on box 1 in the kinematic analysis. In the kinematic analysis, the length (l0) of rod AO and its angle (θ) with the X-axis are... AO ) are two important fixed parameters.

[0087] In the planar linkage system, the lengths and azimuth angles θ of the first link AB, the second link BC, the third link CO, and the virtual fixed link AO are... AOThe length and positional configuration of the five components satisfy the following: during the entire process of the door 2 being driven open from a fully closed state to an opening angle exceeding 90°, the maximum driving torque of the drive unit 100 acting on the first link AB is greater than the total resistance torque acting on the second fixed hinge point O generated by the self-closing force and the resistance of the tilting beam experienced by the door 2 in the fully closed state. This is not a single structural feature, but a comprehensive performance characteristic presented by the synergistic effect of the geometric parameters of the entire linkage system. This means that the planar linkage system optimized in this application possesses the characteristics of a "force-saving lever" in the closed position, capable of amplifying the smaller torque at the drive end to overcome the larger resistance at the door end. For example, assuming that when the door is closed, the sealing strip compression and the tilting beam mechanism together generate a resistance torque of 25 Nm (in the direction of hindering opening). Conventional four-bar linkages in the prior art may require a driving torque of 35 Nm or even greater to start. The optimized four-bar linkage of this application, with its specific bar length and hinge point layout, allows a torque as small as 17 Nm on the drive bar (first link AB) to generate an effective opening torque of over 25 Nm at the second connection point C after transmission and amplification by the mechanism when the door is closed, thus successfully starting the door. This characteristic eliminates the theoretical and physical basis for an independent door-opening mechanism.

[0088] Where l1 is the length of rod AB; l2 is the length of rod BC; l3 is the length of rod CO; and l0 is the length of rod AO. The lengths of the first link AB (l1), the second link BC (l2), the third link CO (l3), the virtual fixed rod AO (l0), and the azimuth angle θ are also considered. AO The matching relationship between them satisfies: 20°≤θ AO ≤60°, 155mm≤l0≤300mm, 50mm≤l1≤115mm, 180mm≤l2≤300mm, 75mm≤l3≤200mm. It should be noted that the given value range does not mean that arbitrarily choosing values ​​within this range will achieve the effect of "effectively overcoming the large resistance torque formed by the door's self-closing force and the reversing force of the tilting beam with a smaller input driving torque." Rather, it requires selecting a parameter value within the above range using the optimization algorithm proposed in this application, with "effectively overcoming the large resistance torque formed by the door's self-closing force and the reversing force of the tilting beam with a smaller input driving torque" as the optimization objective, and then performing optimization according to the optimization algorithm to determine the corresponding values ​​of the other relevant parameters.

[0089] In some embodiments of this application, θ AO =41°, or θ AO =43°, or θ AO =39°, or θ AO =37°, or θ AO =35°, or θ AO=33°, or θ AO =31°, or θ AO =29°, or θ AO =27°, or θ AO =31°.

[0090] In some embodiments of this application, l0 = 190 mm, or l0 = 188 mm, or l0 = 194 mm, or l0 = 204 mm, or l0 = 202 mm, or l0 = 200 mm, or l0 = 214 mm, or l0 = 216 mm, or l0 = 218 mm, or l0 = 222 mm, or l0 = 228 mm, or l0 = 232 mm, or l0 = 242 mm, or l0 = 246 mm, or l0 = 238 mm, or l0 = 234 mm.

[0091] In some embodiments of this application, l1 = 80 mm, or l1 = 84 mm, or l1 = 90 mm, or l1 = 94 mm, or l1 = 100 mm, or l1 = 104 mm, or l1 = 110 mm, or l1 = 114 mm, or l1 = 120 mm, or l1 = 126 mm, or l1 = 130 mm, or l1 = 136 mm, or l1 = 140 mm.

[0092] In some embodiments of this application, l2 = 198 mm, or l2 = 196 mm, or l2 = 202 mm, or l2 = 214 mm, or l2 = 194 mm, or l2 = 212 mm, or l2 = 210 mm, or l2 = 216 mm, or l2 = 220 mm, or l2 = 226 mm, or l2 = 230 mm.

[0093] In some embodiments of this application, l3 = 75mm, or l3 = 80mm, or l3 = 85mm, or l3 = 90mm, or l3 = 95mm, or l3 = 100mm, or l3 = 105mm, or l3 = 110mm, or l3 = 115mm, or l3 = 120mm, or l3 = 125mm, or l3 = 130mm, or l3 = 135mm, or l3 = 140mm.

[0094] For example, a feasible set of implementation parameters is: θ AO =33°, l0=216mm, l1=104mm, l2=210mm, l3=100mm.

[0095] If l1 is too short, it may result in insufficient lever arm; if l1 is too long, it may cause the movement range of point B to exceed the space of the box. When l1 is less than 50mm, the lever arm may be too short, requiring a larger driving force or rematching with other parameters; when l1 is greater than 200mm, the movement range of point B may be too large, and interference with the box should be noted.

[0096] If l2 is too short, it may limit the door opening angle; if l2 is too long, it may also cause spatial interference. When l2 is less than 100mm, it may limit the maximum door opening angle; when l2 is greater than 300mm, it may cause the overall size of the mechanism to be too large.

[0097] l3 determines the position of the hinge point (i.e., the second connection point C) between the second link BC and the door body 2. The shorter l3 is, the closer the second connection point C is to the door body's rotating hinge, which is more conducive to reducing the length of each link and improving the aesthetics of the door opening process. However, if l3 is too short, interference may occur during the door opening process; if l3 is too long, it may lead to an increase in the length of each link, increasing costs and not being conducive to the aesthetics of the door opening process.

[0098] l0 and θ AO This reflects the relative positions of point A and point O, which need to be determined based on the specific dimensions of the refrigerator. These parameters must be correlated with θ. AO (The azimuth angle of the virtual fixed rod AO) is determined collaboratively.

[0099] In this configuration, when the door 2 is fully closed, the first movable hinge point B is located on the side of the first fixed hinge point A closest to the side wall of the housing 1. This technical solution indicates that in the closed state, the connection point B between the drive rod (AB) and the connecting rod (BC) is in a "retracted" position, rather than extending outwards. This arrangement provides a more favorable starting angle for the drive rod (AB) during the initial swinging phase of opening the door, enabling it to more effectively transmit torque to the subsequent connecting rods. Specifically, when point A is fixed and point B is close to and inside point A, when the drive rod (AB) begins to swing counterclockwise to open the door, the direction of the force acting on point B forms a more effective force transmission angle with the axis of the connecting rod BC, contributing to a larger initial force transmission ratio.

[0100] The second link BC is curved, and its curved portion avoids the rotating hinge area of ​​the door 2 when the door 2 is opened to its maximum angle. For example, in sections where straight rods might interfere, the second link BC is designed as an arc or bend that arches away from the hinge system, or has a bend near point C. Thus, when the door is opened to a large angle (e.g., 115°), the curved second link BC can bypass protruding structures on the door hinge box or housing, avoiding collisions and allowing for a larger opening angle.

[0101] The length and positional configuration also satisfy the following: when manually operating door 2, the incremental operating torque added to door 2 due to the planar linkage system is denoted as Tm', where 0.5Nm≤Tm'≤4Nm. To meet this constraint, a mechanical model for manual opening and closing must be established during the optimization design process. During manual operation, the user directly applies force to the door. At this time, the motor is not working, the clutch mechanism is disengaged, and the sun gear 212 can be considered fixed (due to the internal resistance of the motor or electromagnetic brake). The movement of the door will drive the planetary carrier 230 to rotate through the linkage system, thereby driving the gear ring 240 to rotate freely. During this process, the friction and pushing force at the hinge points (A, B, C, O) are the main reasons for the additional operating torque. The optimization algorithm needs to calculate the additional manual opening torque Tm' that the user needs to apply due to these frictions throughout the entire manual opening and closing stroke, and ensure that its maximum increment is within 0.5Nm-4Nm. This makes it so that users can hardly feel the resistance from the automatic mechanism when manually opening and closing the door, maintaining a good manual operation experience.

[0102] When the increase in operating torque is greater than 4Nm, the increase in operating torque is too large. This will cause the increase in manual torque required to open the door 2 of the refrigerator equipped with automatic door opening and closing function to exceed 4Nm in manual mode, making it difficult to open the door and affecting the user experience.

[0103] When the operating torque increment is less than 0.5 Nm, the operating torque increment is too small, which will affect the length of the first link AB (l1), the length of the second link BC (l2), the length of the third link CO (l3), the length of the virtual fixed link AO (l0), and the azimuth angle θ. AO The optimized data increases the maximum driving force Tm(max), making it difficult to effectively overcome the large resistance torque formed by the door's self-closing force and the reversing force of the flip beam with a relatively small input driving torque in the initial stage of door opening.

[0104] In some embodiments of this application, the lengths of the first link AB (l1), the second link BC (l2), the third link CO (l3), the virtual fixed link AO (l0), and the azimuth angle θ are specified. AO Configured as: θ AO =33°, l0=216mm, l1=104mm, l2=210mm, l3=100mm.

[0105] In some embodiments of this application, the lengths of the first link AB (l1), the second link BC (l2), the third link CO (l3), the virtual fixed link AO (l0), and the azimuth angle θ are specified. AO Configured as: θ AO=43°, l0=204mm, l1=84mm, l2=214mm, l3=75mm.

[0106] In some embodiments of this application, the lengths of the first link AB (l1), the second link BC (l2), the third link CO (l3), the virtual fixed link AO (l0), and the azimuth angle θ are specified. AO Configured as: θ AO =39°, l0=194mm, l1=84mm, l2=194mm, l3=80mm.

[0107] In some embodiments of this application, the lengths of the first link AB (l1), the second link BC (l2), the third link CO (l3), the virtual fixed link AO (l0), and the azimuth angle θ are specified. AO Configured as: θ AO =37°, l0=202mm, l1=90mm, l2=202mm, l3=85mm.

[0108] In some embodiments of this application, the lengths of the first link AB (l1), the second link BC (l2), the third link CO (l3), the virtual fixed link AO (l0), and the azimuth angle θ are specified. AO Configured as: θ AO =35°, l0=200mm, l1=94mm, l2=196mm, l3=90mm.

[0109] In some embodiments of this application, the lengths of the first link AB (l1), the second link BC (l2), the third link CO (l3), the virtual fixed link AO (l0), and the azimuth angle θ are specified. AO Configured as: θ AO =35°, l0=214mm, l1=100mm, l2=212mm, l3=95mm.

[0110] In some embodiments of this application, the lengths of the first link AB (l1), the second link BC (l2), the third link CO (l3), the virtual fixed link AO (l0), and the azimuth angle θ are specified. AO Configured as: θ AO =31°, l0=218mm, l1=110mm, l2=210mm, l3=105mm.

[0111] In some embodiments of this application, the lengths of the first link AB (l1), the second link BC (l2), the third link CO (l3), the virtual fixed link AO (l0), and the azimuth angle θ are specified.AO Configured as: θ AO =31°, l0=222mm, l1=114mm, l2=212mm, l3=110mm.

[0112] In some embodiments of this application, the lengths of the first link AB (l1), the second link BC (l2), the third link CO (l3), the virtual fixed link AO (l0), and the azimuth angle θ are specified. AO Configured as: θ AO =29°, l0=228mm, l1=120mm, l2=216mm, l3=115mm.

[0113] In some embodiments of this application, the lengths of the first link AB (l1), the second link BC (l2), the third link CO (l3), the virtual fixed link AO (l0), and the azimuth angle θ are specified. AO Configured as: θ AO =29°, l0=232mm, l1=126mm, l2=220mm, l3=120mm.

[0114] In some embodiments of this application, the lengths of the first link AB (l1), the second link BC (l2), the third link CO (l3), the virtual fixed link AO (l0), and the azimuth angle θ are specified. AO Configured as: θ AO =27°, l0=242mm, l1=130mm, l2=226mm, l3=125mm.

[0115] In some embodiments of this application, the lengths of the first link AB (l1), the second link BC (l2), the third link CO (l3), the virtual fixed link AO (l0), and the azimuth angle θ are specified. AO Configured as: θ AO =27°, l0=246mm, l1=136mm, l2=230mm, l3=130mm.

[0116] In some embodiments of this application, the lengths of the first link AB (l1), the second link BC (l2), the third link CO (l3), the virtual fixed link AO (l0), and the azimuth angle θ are specified. AO Configured as: θ AO =31°, l0=238mm, l1=136mm, l2=226mm, l3=135mm.

[0117] In some embodiments of this application, the lengths of the first link AB (l1), the second link BC (l2), the third link CO (l3), the virtual fixed link AO (l0), and the azimuth angle θ are specified. AO Configured as: θ AO =31°, l0=234mm, l1=140mm, l2=230mm, l3=140mm.

[0118] The length and positional configuration ensures that the maximum opening angle of door 2 is greater than 90°. For example, through optimization, the maximum opening angle θopen(max) can reach 115°, facilitating the storage and retrieval of large items. This is achieved by appropriately setting the lengths of each rod and ensuring no interference during movement. In the optimization model, this is an inequality constraint: θopen(max) > 90° (usually set to > 105° or 110° to allow for margin).

[0119] Specifically, when door 2 is fully closed, the x-coordinate of the first movable hinge point B is less than zero, and its y-coordinate is greater than a preset minimum y-coordinate value (ym). In the set coordinate system XOY, xB<0 and yB>ym constitute the spatial constraint of the movement trajectory of point B, ensuring that point B is located inside the top area of ​​the box (relative to the door seam plane) when the door is closed.

[0120] The first link AB, the second link BC, and the third link CO are all rigid rods, and each hinge point is equipped with a bearing or bushing structure. Using bearings (such as sliding bearings or rolling bearings) or self-lubricating bushings can reduce friction, improve transmission efficiency, make the actual mechanical characteristics of the mechanism closer to the theoretical optimization model, and extend its service life.

[0121] The length and positional configuration relationship is determined through the following steps: (1) Establishing a system of kinematic equations: based on Figure 12 The vector diagram of the four-bar linkage shown has the following properties based on the vector closure principle: Decomposing it onto the x and y coordinate axes yields the following system of kinematic equations: (1) Where l1, l2, l3, and l0 are the rod lengths (design variables), θ1 is the angle between rod AB and the positive X-axis; θ2 is the angle between rod BC and the positive X-axis; θ3 is the angle between rod CO and the positive X-axis; θ4 is the angle between rod AO and the positive X-axis; θ AO The relationship with θ4 is θ AO=360°-θ4. For a given opening angle θopen (the angle between the door rod CO and the initial position), we have θ3=θ3initial±θopen (the sign depends on the direction of rotation). Using this system of equations, given the rod length and θ... AO In this case, θ1 and θ2 corresponding to each door opening angle θopen can be solved.

[0122] Establish a system of mechanical equilibrium equations for multiple working conditions: consider the friction existing at each hinge point (represented by the radius ρ of the friction circle).

[0123] (2) such as Figure 13 As shown, the mechanical model of the automatic door opening process is as follows: Taking the moment balance at point O of rod OC (i.e., door rod CO), we obtain equation (2): (2) Where T f It is the door resistance torque (known or measurable), F 23 It is the force exerted by the BC rod on the OC rod. It is the radius of the friction circle at hinge point C. It is the radius of the friction circle at the hinge point O.

[0124] |T f | This is preset data, representing the torque required to open or close the door.

[0125] Taking the moment equilibrium at point A of rod AB, we obtain equation (3): (3) Where T m It is the required driving torque (target), F 21 It is the force exerted by rod BC on rod AB.

[0126] Since member BC is a two-force member, F 21 =F 23 Solve equations (2) and (3) simultaneously, and eliminate F. 21 / F 23 The driving torque T is obtained. m With the door resistance torque T f Relationship (4): (4) Similarly, an automatic door closing mechanism can be established. Figure 14 ), manual door opening ( Figure 15 ), manual door closing ( Figure 16 The mechanical equilibrium equations of ) are obtained as follows: (5), (6), and (7); Automatic door closing process: (5) Manual door opening process: (6) Manual door closing process: (7) These formulas have similar structures, but the signs before the friction term are different, reflecting the hindering effect of friction in different directions of motion.

[0127] Define the optimization objective and constraints: Objective function: Minimize the maximum value of the maximum driving torque Tm of the drive rod during the automatic opening and closing process. That is, minimize max(max(Tmopen(θ)), max(Tmclose(θ))), where Tmopen(θ) and Tmclose(θ) are the driving torque curves that vary with the opening angle θ, calculated using the above formulas (4) and (5).

[0128] Constraints: θopen(max)>90° (maximum door opening angle constraint).

[0129] max(Tm'open(θ))≤2Nm and max(Tm'close(θ))≤2Nm (manual operation with additional torque constraint, Tm' is calculated by formulas (6) and (7).

[0130] xB(θ)<0 and yB(θ)>ym, for all θ∈[0, θopen(max)] (B-point motion space constraint, xB, yB can be calculated from the kinematic equations).

[0131] Four-bar linkage link length conditions (e.g., satisfying the Grashov condition, etc., to ensure that the mechanism can rotate a full circle or meet the predetermined swing range).

[0132] Boundary constraints for design variables (e.g., l1, l2, l3, l0, θ) AO (The reasonable range of values).

[0133] Numerical optimization solution: The above objective function and constraints constitute a nonlinear constrained optimization problem. The design variables are X = [l1, l2, l3, l0, θ]. AO Due to the complexity of the problem, analytical solutions are difficult to obtain, and numerical optimization algorithms are typically employed. Wherein, θ AO The relationship with θ4 is θ AO =360°-θ4. The final output is a set of optimized parameter values.

[0134] Optimize processes such as Figure 17 As shown: a. Given the initial guessed value of the design variable X.

[0135] b. Verify whether the link length condition of the four-bar linkage is met. If not, return "fail".

[0136] c. Calculate θ1initial when the door is closed and the maximum opening angle θopen(max) based on the kinematic equations. Determine whether θopen(max) > 90° satisfies the condition.

[0137] d. Discretize the door opening stroke into N points, and calculate the required torque Tm for automatic door opening and the additional torque Tm' for manual door opening at each point. Determine whether Tm'≤2Nm is satisfied throughout the entire stroke.

[0138] e. Find the maximum value of Tm during the automatic door opening process: Tmopenmax.

[0139] f. Similarly, discretely calculate the door closing stroke, including automatic closing Tm and manual closing Tm', and determine the constraint of Tm'. Find the maximum value of automatic closing Tm, Tmclosemax.

[0140] g. Calculate the objective function value max(Tmopenmax, Tmclosemax).

[0141] h. According to the rules of the optimization algorithm (such as genetic algorithm, particle swarm optimization), determine whether the termination condition is met (such as reaching the maximum number of iterations or the objective function improving very little). If met, output the current optimal X; if not, the algorithm generates a new design variable X and returns to step b to continue iterating.

[0142] Through the above systematic and procedural design methods, one (or more) sets of optimal or near-optimal linkage system parameters [l1, l2, l3, l0, θ] can be found efficiently and reliably. AO The power conversion unit 300 defined by this set of parameters possesses the core characteristic of "small torque driving large resistance" and simultaneously meets all performance requirements such as large door opening angle, easy manual operation, and no interference in movement.

[0143] It should be noted that the above "kinematic equations" refer to the set of mathematical equations describing the geometric relationships between the positions, velocities, and accelerations of the components in the mechanism, and do not involve the action of forces.

[0144] In this application, "mechanical equilibrium equations" refers to a set of mathematical equations that describe the balance relationship between external forces, internal forces and torques acting on each component of a mechanism under specific working conditions, based on the principles of statics.

[0145] In this application, the "friction circle radius" is a simplified model parameter used in mechanical principles to calculate the friction torque in a rotating pair. Its value is related to the hinge radius, the coefficient of friction, and the force conditions.

[0146] The power conversion unit 300 in this application differs fundamentally from other similar technologies (such as those employing a composite scheme of "top door mechanism + traditional rotary door mechanism") in that it is a single four-bar linkage designed with systematic and multi-objective optimization. It is designed to independently handle the entire driving process from the door's closed, high-resistance state to full opening. In other words, the power conversion unit 300 is the sole actuator responsible for driving the door from closing to full opening, completely eliminating the need for a separate top door mechanism.

[0147] In other similar technologies, the "revolving door mechanism" is usually just a conventional linkage or gear mechanism that has not been deeply optimized for the special resistance curve of the refrigerator door. It cannot solve the problem of high initial resistance on its own, so it must rely on an additional "top door mechanism" that is independent in function and structure to start. The power conversion unit (usually referring only to the revolving door mechanism) is only responsible for the large-angle opening stage and needs the assistance of the top door mechanism to start. Therefore, there is a fundamental difference between the two in terms of system architecture and functional completeness. Thus, the power conversion unit 300 of this application solves the industry problem that a single mechanism cannot cope with the large initial resistance torque through its own optimized design, and achieves extreme simplification of the mechanism and smooth and continuous movement throughout the process. It eliminates a series of chain problems caused by the switching of two mechanisms, such as unevenness, swaying, structural complexity, high cost, and poor aesthetics.

[0148] The control unit (not shown separately in the figure, but mentioned in the description) can be a circuit board based on a microprocessor (MCU) or a dedicated control chip, and typically includes a power module, signal input interface, motor drive circuit, electromagnet drive circuit, and communication interface.

[0149] The control unit, based on its functions of receiving commands, processing sensor signals, and controlling actuator actions, acts as the central command in the system. For example, the control unit receives door opening and closing commands from the user interface (buttons, touchscreen, voice module) or network module, and also receives feedback signals from the angle detection unit 500 or limit switches.

[0150] The control unit is electrically connected to the motor 110 drive circuit of the drive unit 100, electrically connected to the electromagnet 251 drive circuit of the clutch mechanism 200, and electrically connected to the signal output terminal of the angle detection unit 500 or the limit switch.

[0151] During the automatic door opening and closing operation, the control unit has a first state (waiting for instructions), in which it operates in a low-power monitoring state. In the second state (executing the automatic door opening command), the control unit first energizes the electromagnet 251, engaging the clutch mechanism 200. Then, it controls the motor 110 to rotate forward according to a preset speed curve (e.g., acceleration at startup, constant speed in the middle, and deceleration near the target angle). During operation, it reads the signal from the angle detection unit 500 in real time to calculate the current door angle. When the detected angle reaches the preset target opening angle (e.g., 115°), it stops the motor 110, then de-energizes the electromagnet 251 after a short delay, switching to manual mode. In the third state (executing the automatic door closing command), the process is similar, but the motor 110 reverses direction, the target angle is 0° (fully closed), and the first limit switch or the angle detection unit 500 determines that the door is closed correctly. The control unit has a fourth state (abnormal handling). For example, if an abnormal angle change (such as being blocked) or an abnormal increase in motor current is detected during automatic operation, the motor will be stopped immediately, the clutch will be released, the system will switch to manual mode, and an alarm will be triggered.

[0152] The control unit is electrically connected to the drive unit 100 and is used to control the automatic opening and closing of the door 2. The control unit is configured to adjust the output of the drive unit 100 based on the real-time angle feedback signal of the door 2. For example, the control unit uses a PID control algorithm, taking the difference between the target angle and the actual angle as the error, and adjusts the motor torque and speed by adjusting the PWM duty cycle output to the motor 110 to achieve precise closed-loop position control.

[0153] Unlike other similar technologies that may employ open-loop time control or simple position switch control, the control unit in this application enables closed-loop control based on angle feedback, thereby achieving more precise position control and smoother speed control. In some low-cost applications, only two limit switches (door open position, door close position) may be used for control. Therefore, there are differences in control accuracy and smoothness, resulting in the control unit of this application providing a superior user experience and more reliable position stopping.

[0154] Angle detection unit 500, such as Figures 4-5 and Figures 7-8 As shown, it is used to detect the swing angle of the first link AB or the opening angle of the door 2 and generate an angle feedback signal.

[0155] The angle detection unit 500, based on its function of providing position feedback, acts as the "eye" in the system and is a prerequisite for achieving closed-loop control.

[0156] Angle detection unit 500, whose sensor body is fixed to the housing 1 or the drive unit 100 housing. Its detection components (such as gears, encoders) are linked to the first connecting rod AB or the shaft that drives its rotation. Its signal output terminal is connected to the control unit.

[0157] During operation, when the first link AB swings, the angle detection unit 500 drives the detection component linked with it to rotate synchronously. The angle detection unit 500 converts this mechanical rotation angle into an electrical signal (such as analog voltage, PWM wave, digital code) and outputs it to the control unit.

[0158] The angle detection unit 500 can be a rotary encoder (incremental or absolute), a potentiometer, or a combination of angle sensors driven by a gear pair.

[0159] The angle detection unit 500, based on the function of providing an electrical signal proportional to the angular position of the door body 2 or the drive shaft, provides the control unit in the system with the feedback information necessary for realizing position closed-loop control and status monitoring.

[0160] The refrigerator automatic door opening and closing device includes an angle detection device for detecting the swing angle of the first link AB or the opening angle of the door 2 and generating an angle feedback signal.

[0161] The angle detection device includes a first gear section 232 mounted on a component that rotates synchronously with the first connecting rod AB, and a detection gear 400 meshing with the first gear section 232. For example, an extended arc is provided on the end face of the planetary carrier 230, and an incomplete gear is machined on this arc to form the first gear section 232. A separate detection gear 400 meshes with the first gear section 232, and an angle detection unit 500 (such as a potentiometer or rotary encoder) is mounted on the shaft of the detection gear 400. The rotation of the planetary carrier 230 is transmitted and decelerated through the gear pair before being detected by the angle detection unit 500. The gear ratio design ensures that the sensor rotation range corresponding to the entire stroke of the door is within its effective range, thus improving resolution.

[0162] Example: The first gear section 232 has fewer teeth, for example, only 10-20 teeth, covering an arc range of approximately 120°, corresponding to the entire stroke of the door. The detection gear 400 has even fewer teeth, for example, 5-10 teeth, to achieve deceleration and increased distance, improving the resolution accuracy of the angle sensor. The angle detection unit 500 can be a single-turn absolute encoder with a range of 0-360°. After gear deceleration, the entire stroke of the door (0-115°) corresponds to an encoder rotation angle of approximately 60-100°, fully utilizing its range and improving detection resolution and control accuracy.

[0163] During operation, when the planetary carrier 230 drives the first gear section 232 to rotate, the detection gear 400 meshing with it rotates in the opposite (or same) direction at a certain transmission ratio. The angle detection unit 500 mounted on the shaft of the detection gear 400 converts the angle change of its shaft into a change in voltage, resistance, or digital pulse signal. By reading this signal and calibrating according to the gear transmission ratio and the initial position, the control unit can calculate the current absolute rotation angle of the planetary carrier 230, and then deduce the opening and closing angle of the gate 2.

[0164] In some embodiments of this application, angle detection can also be performed in other ways, such as: 1) directly installing an absolute encoder on the rotation shaft of the door body 2; 2) installing a magnet and a Hall sensor on the housing 1 and the door body 2 respectively, and calculating the angle by detecting changes in the magnetic field; 3) using a potentiometer coaxially connected to the swing shaft of the first connecting rod AB.

[0165] Unlike simple solutions using only limit switches, the angle detection unit 500 of this application can provide continuous, high-resolution angle information. This allows the control unit to not only achieve precise end-position control but also implement fine-grained speed and acceleration control throughout the entire movement, resulting in extremely smooth and fluid door opening and closing actions, enhancing the user experience of high-end products. It can also detect anomalies during operation (such as angle stagnation when obstructed). In contrast, the limit switch solution can only provide trigger signals for two extreme positions, leaving the intermediate process uncontrollable, resulting in poor movement smoothness and lower control precision and flexibility. Therefore, there is a significant difference in control precision between the two.

[0166] The limit switch unit can serve as a low-cost alternative or supplement to the angle detection unit 500. The first limit switch is used to detect the position where the door 2 is fully closed. The second limit switch is used to detect the position where the door 2 is opened to the maximum preset angle.

[0167] Limit switch units, based on their function of providing limit position switching signals, play a role in position detection in low-cost applications.

[0168] The limit switch unit consists of two parts. The first limit switch is typically mounted on the housing 1, and its trigger (such as a button) is located at the position reached when the door 2 is closed. The second limit switch is also mounted on the housing 1, and its trigger position corresponds to the position reached by the trigger (such as the arc curve 604 at the end of the lever 603) located on the door 2 or the planetary carrier 230 when the door is opened to its maximum angle.

[0169] During operation, when the door 2 moves to the fully closed position, the door presses the trigger button of the first limit switch, changing the switch state, and the control unit receives a "door closed" signal. When the door 2 opens to its maximum angle during automatic opening, the arc curve at the end of the swing rod 603 fixed on the planetary carrier 230 touches the trigger of the second limit switch, changing the switch state, and the control unit receives a "door open" signal.

[0170] The first limit switch is a detection element originally built into the refrigerator body, generally used to detect whether the refrigerator door is open. Once the refrigerator door is detected to be open, it controls the refrigerator to perform actions such as turning on the internal lights. The first limit switch used in the automatic door opening device can be the same as the original door closing position limit switch built into the refrigerator. This achieves resource sharing and reduces costs.

[0171] Limit switch units offer significantly lower costs compared to angle sensor solutions, but they can only provide two-point position signals, making precise control and monitoring of intermediate processes impossible. Therefore, they are suitable for refrigerator models where cost is a concern and control precision requirements are not high.

[0172] Under different operating states of the overall system, the collaborative work between the various components of the overall system is as follows: Automatic door opening state: The user issues an opening command → The control unit drives the electromagnet 251 to be energized, and the locking part 252 locks the gear ring 240 → The control unit drives the motor 110 to rotate in the forward direction → The power is transmitted to the first link AB through the reduction transmission mechanism 120 (at this time the gear ring is fixed and the planetary carrier outputs) → The first link AB swings around point A → It is transmitted through the second link BC and the third link CO, causing the door body 2 to rotate around point O and open → The angle detection unit 500 provides real-time feedback on the angle → When the control unit determines that the angle has reached the preset opening angle (or the second limit switch is triggered) → The control unit controls the motor 110 to stop working → After a set delay time, the electromagnet 251 is released, and the system switches to manual mode.

[0173] Automatic door closing state: When the user issues a door closing command → the control unit drives the electromagnet 251 to be energized and locked → the control unit drives the motor 110 to rotate in the opposite direction → the power transmission path is the same as the door opening but in the opposite direction, driving the door body 2 to close → when the control unit judges that the angle is 0° (or the first limit switch is triggered) → the control unit controls the motor 110 to stop working → after a set delay time, the electromagnet 251 is released.

[0174] Manual mode: Electromagnet 251 is de-energized, locking element 252 disengages, and gear ring 240 is free. The user can then freely open and close the door manually. When manually opening the door, the rotation of the door body 2 drives the planetary carrier 230 to rotate via the third link CO, the second link BC, and the first link AB. Since gear ring 240 is free, planetary gears 220 revolve around the sun gear 212, causing the gear ring to rotate freely, and the motor shaft is not under load. The optimized linkage system ensures a minimal increase in manual operating force.

[0175] Overload protection: In automatic mode, if the door is subjected to an abnormally violent impact, a torque, Timpact, far exceeding the normal value, is generated in the transmission chain. This torque generates a huge radial separation force, Frimpact, through the engagement ramp between the gear ring 240 and the locking element 252. This force exceeds the holding force of the electromagnet 251, forcibly pushing the locking element 252 open. The gear ring 240 instantly becomes free, and the power transmission is mechanically cut off, protecting the gears and other transmission components from damage.

[0176] The core problem with existing technological inertia lies in its view of the two technical elements of "overcoming high initial resistance" and "using a single revolving door mechanism" as irreconcilable conflicts, thus assuming that the problem must be solved through an extensional approach of "adding additional mechanisms." This thinking fails to delve into the plasticity and optimization potential of the force transmission performance of the revolving door mechanism (four-bar linkage) itself, and ignores the possibility that by systematically and meticulously designing its internal geometric parameters, it is entirely possible to reshape its torque output characteristics, thereby enabling it to independently handle the task of starting from a state of high initial resistance and completing the entire door opening process.

[0177] To overcome the aforementioned technical problems, this application abandons the conventional thinking of "adding components" and instead adopts an intrinsic problem-solving mechanism of "optimizing the performance of core components." Specifically, the core mechanism of this application lies in: performing multi-objective, multi-constraint system engineering optimization design on the planar four-bar linkage system constituting the revolving door mechanism, configuring its geometric parameters (length of each bar, initial position of the hinge point) into a specific combination. This combination enables the mechanism to achieve an optimal or near-optimal force transmission ratio throughout the entire opening and closing stroke, especially in the fully closed state where resistance is greatest. To achieve this mechanism, this application adopts the following key technical means: First, the revolving door mechanism is abstracted into a standard planar four-bar linkage kinematic model, and its static equilibrium equations are established under four typical working conditions: automatic opening, automatic closing, manual opening, and manual closing, thereby accurately describing the complex mapping relationship between the driving torque and the door resistance torque. Secondly, with minimizing the maximum driving torque required by the drive lever as the core optimization objective, and taking the maximum opening angle of the door, the additional torque for manual operation, and the motion space boundary of the movable hinge point as hard constraints, a complete mathematical model of the constrained optimization problem is constructed. Finally, a numerical optimization algorithm (such as an intelligent optimization algorithm) is used to solve the model to find a set of optimal mechanism parameters that satisfy all performance and geometric constraints and minimize the driving torque requirement.

[0178] Through the aforementioned technical means, this application enables the optimized four-bar linkage to possess force transmission characteristics significantly superior to conventional designs even when the door is closed. This achieves the goal of overcoming a large resistance torque on the door with a relatively small drive input torque—the core effect of "small torque driving large resistance." Furthermore, this fundamental performance improvement makes it possible for the linkage to independently handle the task of fully automatic door opening and closing, thus completely eliminating the need for the aforementioned top-mounted mechanism and all its auxiliary components (such as top rods, drive channels, and buffer springs).

[0179] Therefore, this application achieves a series of positive technical effects: First, by eliminating the switching action between mechanisms, the entire movement of the door from rest to full opening is continuously driven by a single mechanism, fundamentally improving the smoothness of movement. Second, it eliminates the motion swaying problem that may be caused by the interaction of the switching mechanism, spring buffer, and self-closing force cam, making operation more reliable. Third, by eliminating the exposed ejector rod and the corresponding openings and gaps, the outer surface of the refrigerator cabinet can remain intact and flat, significantly improving aesthetics. Finally, the number of parts in the entire actuator is greatly reduced, the structure is simplified, and material costs and assembly complexity are directly reduced.

[0180] Furthermore, the mechanism of "systematic parameter optimization to reshape the original performance of the mechanism" adopted in this application completely breaks the deep-seated technical inertia of "requiring the superposition of auxiliary drive mechanisms when facing large initial resistance" in traditional technology. This shift in thinking reconstructs the design paradigm of the refrigerator's automatic door opening and closing mechanism, moving from a "combinatorial" design that relies on the series collaboration of multiple mechanisms to an "integrated optimization" design that deeply explores the performance potential of a single core mechanism. Ultimately, this reconstruction not only solves problems related to stability, reliability, aesthetics, and cost, but also achieves a higher level of unity between system performance and integration.

[0181] Therefore, this application, through a redesign methodology for the revolving door mechanism and refined design methods based on multi-condition coupled modeling and numerical optimization, solves the historical problem that a single mechanism cannot efficiently overcome the large initial resistance torque of the refrigerator door. Furthermore, this solution demonstrates in practice that, through deep optimization, the traditional four-bar linkage mechanism can meet the stringent performance requirements of automatic door opening and closing in refrigerators. This breaks through the long-standing technical prejudice in the industry that "automatic door opening must rely on the top door mechanism for activation," providing a new approach and model for the compact, efficient, and low-cost design of actuators in household appliances.

[0182] In this application, "length and positional configuration relationship" refers to the length dimension and combined azimuth angle θ of each link (first link AB, second link BC, third link CO, and virtual fixed link AO) constituting the planar linkage system. AO The defined relative spatial relationships determine the force and torque transmission characteristics of the linkage system during motion.

[0183] In this application, "maximum driving torque" refers to the maximum torque value that the output end of the drive unit 100 needs to apply during the entire process of driving the door body 2 to complete one complete automatic opening or closing action.

[0184] In this application, "total resistance torque" refers to the sum of all torques that resist the opening of the door when the door 2 is in a fully closed state, acting on its rotation axis (second fixed hinge point O). It mainly includes the self-closing torque generated by the compression of the door seal and the reversing torque generated by the flip beam mechanism.

[0185] In this application, "planar linkage system" refers to a mechanism in which all moving components move in mutually parallel planes, and the components are connected by revolute joints (hinges). Specifically, in this application, it refers to a closed four-bar linkage consisting of a first link AB, a second link BC, a third link CO, and a virtual fixed link AO.

[0186] In this application, "virtual fixed rod AO" refers to an imaginary line segment connecting the first fixed hinge point A and the second fixed hinge point O, combined with the azimuth angle θ. AOIts length and spatial orientation are fixed, and it is used to characterize the geometric constraints between two fixed hinge points on box 1 in kinematic analysis.

[0187] In this application, "operating torque increment" refers to the additional torque value that the user needs to apply when manually operating the door 2, due to the presence of the power conversion unit 300, compared to a door without the unit installed.

[0188] In this application, "reduction transmission mechanism" refers to a mechanical transmission device used to reduce the speed of the drive motor and increase the output torque, and its form includes, but is not limited to, planetary gear reducers, harmonic reducers, worm gear reducers or multi-stage parallel shaft gear reducers.

[0189] In this application, "clutch mechanism" refers to a device used to connect or disconnect the power transmission between the engine (or drive source) and the driven parts, and in this application, it is used to switch between automatic mode (power on) and manual mode (power off).

[0190] In this application, "angle feedback signal" refers to an electrical signal generated by the angle detection device that is proportional to or has a definite functional relationship with the real-time angular position of the door body 2 or the drive linkage. This signal is provided to the control unit to realize closed-loop control.

[0191] In this application, "constrained optimization problem" refers to a mathematical problem that seeks a set of decision variables (such as rod length and angle) that minimize or maximize a certain objective function under the premise of satisfying a series of equality or inequality constraints.

[0192] This application provides a scenario for the use of an automatic door opening and closing device for a refrigerator. Users can issue commands to the refrigerator to "automatically open" or "automatically close" via voice commands, touchscreen buttons, or a mobile application. Upon receiving the command, the refrigerator's control unit controls the drive unit and clutch mechanism to smoothly open the door to a preset angle or close it to a sealed state. During automatic operation, if the user intervenes manually (such as blocking or pushing the door), the device can switch to manual mode to ensure safety and flexibility.

[0193] 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.

[0194] 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, comprising: The box (1) has a door (2) on its front side, and the door (2) is rotatably connected to the box (1) by a hinge system. A drive unit (100) is mounted on the housing (1) and is used to output rotational power; A power conversion unit (300) is connected between the output end of the drive unit (100) and the door body (2) to convert the rotational power into an action that drives the door body (2) to swing around its rotation axis. The power conversion unit (300) is a planar linkage system consisting of a first link (AB), a second link (BC), a third link (CO), and a virtual fixed link (AO) hinged together. Wherein, the first end of the first connecting rod (AB) is hinged to the first fixed hinge point (A) on the box (1), and its second end is hinged to the first end of the second connecting rod (BC) at the first movable hinge point (B). The second end of the second link (BC) is hinged to the first end of the third link (CO) at the second connection point (C). The second end of the third link (CO) is hinged to the second fixed hinge point (O) on the door body (2), and the second fixed hinge point (O) is located on the rotation axis of the door body (2); The output end of the drive unit (100) is connected to the first connecting rod (AB) for driving the first connecting rod (AB) to swing around the first fixed hinge point (A); Its features are, The line connecting the first fixed hinge point (A) and the second fixed hinge point (O) forms a virtual fixed rod (AO); The acute angle between the virtual fixed rod (AO) and the plane containing the door (2) in the fully closed state constitutes the azimuth angle θ of the virtual fixed rod (AO). AO ; In the planar linkage system, the lengths of the first link (AB), the second link (BC), the third link (CO), and the virtual fixed link (AO), and the azimuth angle θ AO The length and positional arrangement relationships among the five angles satisfy: During the entire process of the door (2) being driven open from a fully closed state to an opening angle of more than 90°, the maximum driving torque of the drive unit (100) acting on the first link (AB) is greater than the total resistance torque generated by the self-closing force and the resistance of the flip beam that the door (2) experiences in the fully closed state and acts on the second fixed hinge point (O).

2. The automatic door opening and closing device for a refrigerator according to claim 1, characterized in that, The length l1 of the first link (AB), the length l2 of the second link (BC), the length l3 of the third link (CO), the length l0 of the virtual fixed rod (AO), and the azimuth angle θ AO The matching relationship between them is denoted as the length and position configuration relationship; The length and positional configuration relationship satisfies: 20°≤θ AO ≤60°, 155mm≤l0≤300mm, 50mm≤l1≤115mm, 180mm≤l2≤300mm, 75mm≤l3≤200mm.

3. The refrigerator automatic door opening and closing device according to any one of claims 1-2, characterized in that, The length and position configuration relationship also satisfies that: when the door (2) is manually operated, the incremental operating torque added to the door (2) due to the presence of the planar linkage system is denoted as Tm', where 0.5Nm≤Tm'≤4Nm.

4. The automatic door opening and closing device for a refrigerator according to claim 1, characterized in that, The cabinet defines a storage space with an access opening, and the door opens or closes the access opening. In the plane containing the top wall of the enclosure, with the second fixed hinge point (O) as the origin, a straight line parallel to the plane containing the access opening 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 containing the access opening is denoted as the Y-axis. The door includes a connecting end connected to the housing and a free end opposite to the connecting end. When the door is open, the free end rotates around the connecting end. When the door is closed, the direction of the free end pointing to the connecting end is denoted as the positive direction of the X-axis. The direction of the plane where the access opening is located pointing to the rear wall of the housing is denoted as the positive direction of the Y-axis, forming a two-dimensional coordinate system XOY. The Y-coordinate of the plane where the access opening is located is ym; When the door (2) is in a fully closed state, the x-coordinate value of the first movable hinge point (B) is less than zero, and its y-coordinate value is greater than ym.

5. The automatic door opening and closing device for a refrigerator according to claim 1, characterized in that, The hinge point (O) between the third link (CO) and the door (2) is located on the rotation axis of the door (2) and close to the edge of the door (2) away from the box (1) when it is in the fully closed state.

6. The automatic door opening and closing device for a refrigerator according to claim 1, characterized in that, The drive unit (100) includes a motor (110) and a speed reduction transmission mechanism (120), the output end of which is connected to the first connecting rod (AB) in a transmission connection.

7. The automatic door opening and closing device for a refrigerator according to claim 6, characterized in that, The speed reduction transmission mechanism (120) is a planetary gear reducer, and its planet carrier (230) forms the output end of the drive unit (100) and is connected to the first connecting rod (AB) in a transmission.

8. The automatic door opening and closing device for a refrigerator according to claim 6 or 7, characterized in that, The refrigerator automatic door opening and closing device also includes a clutch mechanism (200), which is located between the motor (110) and the reduction transmission mechanism (120), or integrated inside the reduction transmission mechanism (120), and is used to switch between automatic mode and manual mode.

9. The automatic door opening and closing device for a refrigerator according to claim 8, characterized in that, The speed reduction transmission mechanism (120) includes a rotating component; the rotating component is provided with mating teeth (242). The clutch mechanism (200) is an electromagnetic clutch mechanism, which includes a locking member (252) that can be driven by electromagnetic force. The locking member (252) has a locking position and an unlocking position that engage or disengage with the mating teeth (242).

10. The automatic door opening and closing device for a refrigerator according to claim 9, characterized in that, The mating surfaces of the mating teeth (242) and the locking member (252) are respectively provided with mutually mating inclined teeth; when the two are mated, the inclined teeth cooperate with each other to prevent the rotating component from rotating relative to each other in the circumferential direction. This state is the automatic mode. When the torque borne by the rotating component exceeds a set threshold, the radial separation force generated by the mating surface can overcome the electromagnetic force and cause the locking member (252) to disengage from the mating tooth (242). This state is manual mode.

11. A refrigerator, characterized in that, Includes the refrigerator automatic door opening and closing device as described in any one of claims 1 to 10.

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