Massage chair leg driving mechanism

Abstract

The utility model relates to massage chair technical field, more particularly, relate to a massage chair leg drive mechanism. Through adopting double shaft output motor to drive left and right leg support assembly simultaneously, and combining with the two thread connectors of opposite rotation, make two screw rods produce the axial movement of opposite direction when the motor same direction rotation, to drive left and right leg support assembly realizes asynchronous motion. This structure only needs a motor to realize the action of double legs independent, asymmetric, can simulate more natural leg alternate movement, significantly improves the massage comfort degree and the real feeling, reduces the number of motor, reduces cost and energy consumption simultaneously.

Description

Technical Field

[0001] This utility model relates to the field of massage chair technology, and more specifically, to a massage chair leg drive mechanism that enables asynchronous movement of the left and right leg components. Background Technology

[0002] With increasing health awareness, massage chairs, as a relaxing and health-promoting device, have become widely used in homes and public places. Existing massage chairs typically include leg massage functions, using a drive mechanism to raise or lower the leg support assembly to massage the thighs, calves, and feet.

[0003] Currently, most common massage chair leg drive mechanisms use a single motor to simultaneously drive the left and right leg support components via a transmission rod, gearbox, or steel cable, ensuring that the legs move completely synchronously (lifting or lowering simultaneously). This synchronous movement mode starts in the initial state (legs level) and remains level and synchronized throughout the operation. It cannot simulate the asymmetrical posture of the legs moving back and forth and alternating during natural walking, kicking, or kneading, thus limiting the massage comfort and effectiveness.

[0004] To address these issues, some massage chairs employ two independent motors to drive the left and right leg support components separately, enabling asynchronous movement. While this solution allows the legs to be misaligned during operation, it requires two motors and two independent control systems, resulting in high cost and complex structure. More importantly, when the massage ends and the legs need to be reset, this dual-motor solution typically requires complex sensors and control algorithms to restore the legs to their initial aligned position. If the control is flawed, the left and right legs can easily fail to reset synchronously, resulting in one leg being higher than the other, severely impacting the user experience.

[0005] In addition, there is another solution in the existing technology: asynchronous movement is achieved through mechanical structure. However, this solution often results in a fixed offset in the initial position of the legs (e.g., the left leg is higher and the right leg is lower), and it cannot automatically return to the initial state of being completely aligned before each use, which does not meet the needs of the massage chair for initial storage or the user's comfortable sitting.

[0006] Therefore, how to achieve the complete dynamic process of "initial alignment → working misalignment → reset alignment" of the massage chair leg drive mechanism with a low-cost, simple and reliable structure is a technical problem that urgently needs to be solved in this field. Utility Model Content

[0007] The purpose of this utility model is to overcome the shortcomings of the prior art and provide a massage chair leg drive mechanism to solve the problem that the prior art cannot achieve the dynamic switching of the left and right leg support components from a level state to a misaligned working state with low cost and simple structure, and restore the level state after reset.

[0008] To achieve the above objectives, the present invention adopts the following technical solution: A massage chair leg drive mechanism includes a massage chair frame and a left leg support assembly and a right leg support assembly respectively mounted on the massage chair frame, and also includes a dual-axis output motor, a first transmission assembly and a second transmission assembly; One output shaft of the dual-axis output motor is connected to the left leg support assembly via the first transmission assembly; The other output shaft of the dual-axis output motor is connected to the right leg support assembly via the second transmission assembly; The first transmission assembly and the second transmission assembly each include a screw and a threaded connector fixedly sleeved on the screw. The threaded connectors of the first transmission assembly and the second transmission assembly have opposite thread directions. The two output shafts of the dual-axis output motor simultaneously drive the two threaded connectors. The two screws respectively drive the left leg support assembly and the right leg support assembly, causing the left leg support assembly and the right leg support assembly to produce asynchronous motion. The screw is provided with a nut seat that mates with it. The nut seat is hinged to the corresponding left leg support assembly or right leg support assembly. The left leg support assembly and the right leg support assembly each include a leg bracket and a linkage mechanism hinged to the massage chair frame. The nut seat is hinged to one end of the linkage mechanism, and the other end of the linkage mechanism is connected to the leg bracket. The linkage mechanism is a two-bar linkage, which includes a first link and a second link. One end of the first link is hinged to a nut seat, and the other end of the first link is hinged to the middle of the second link. One end of the second link is hinged to the massage chair frame, and the other end of the second link is fixedly connected to the leg support. One of the two first links is configured to have an adjustable length, while the other first link is configured to have a non-adjustable length.

[0009] Furthermore, the length-adjustable first connecting rod includes a first sleeve, a second sleeve, and a locking element. The first sleeve and the second sleeve are nested together, and the locking element is installed at the connection between the first sleeve and the second sleeve and is used to lock the relative position between the first sleeve and the second sleeve.

[0010] Furthermore, at least two position sensors are provided on the first sleeve or the second sleeve, respectively for sensing the relative positions of the first sleeve and the second sleeve in two states: when they are retracted and when they are extended. The two position sensors are respectively electrically connected to the drive end of the locking member.

[0011] Furthermore, the locking element is a needle cylinder, and the direction of movement of the needle cylinder is perpendicular to the axis of the first sleeve or the second sleeve.

[0012] Furthermore, the massage chair frame includes a first crossbeam and a second crossbeam. The first crossbeam is positioned closer to the leg support component than the second crossbeam. One end of the screw is mounted on the first crossbeam via a bearing seat, and the other end of the screw is mounted on the second crossbeam via another bearing seat.

[0013] Furthermore, the first transmission component and the second transmission component are arranged parallel to each other and horizontally spaced apart, and the dual-axis output motor is located between the first transmission component and the second transmission component.

[0014] Furthermore, a bearing is fitted onto the screw, and the housing of the dual-shaft output motor is fitted onto the bearing.

[0015] Furthermore, the screw is inclined, with one end of the screw near the leg support assembly being higher than the other end of the screw away from the leg support assembly, and the bearing is located on the end of the screw away from the leg support assembly.

[0016] Furthermore, the massage chair frame includes a base frame and a backrest frame hinged to the base frame, and the leg drive mechanism is mounted on one side of the base frame.

[0017] Furthermore, the dual-axis output motor, the first transmission assembly, and the second transmission assembly are respectively disposed inside the base frame.

[0018] Compared with the prior art, this utility model has the following advantages: This utility model provides a leg drive mechanism for a massage chair. It employs a dual-axis output motor to simultaneously drive the left and right leg support components, combined with two threaded connectors with opposite rotation directions. This causes the two screws to move axially in opposite directions when the motors rotate in the same direction, thereby driving the left and right leg support components to achieve asynchronous movement. This structure requires only one motor to achieve independent, asymmetrical leg movements, simulating more natural alternating leg movements, significantly improving massage comfort and realism, while reducing the number of motors, lowering costs and energy consumption. Furthermore, by setting the first link in the linkage mechanism on both sides to be adjustable and non-adjustable respectively, and coordinating with a specific control sequence (initially, the adjustable side unlocks, the motor drives it to extend to its limit and then locks it, forming a misalignment reference; during reset, it unlocks and retracts after reaching its lowest position, restoring alignment), this mechanism can automatically switch from an initial state of left and right alignment to a stable misaligned movement state at the start of each massage, and reliably return to the initial state of left and right alignment after the massage ends. This solution eliminates the need for dual motors and complex reset algorithms, resulting in a simple structure, low cost, high flatness after each reset, and a good user experience. Attached Figure Description

[0019] Figure 1 This is a first-view overall structural schematic diagram of the leg drive mechanism of a massage chair according to this utility model. Figure 2 yes Figure 1 A magnified view of a section at point A in the middle; Figure 3 This is a second-view overall structural schematic diagram of the leg drive mechanism of a massage chair according to this utility model. Figure 4 yes Figure 3 A magnified view of a section at point B in the middle; Figure 5 This is a third-view schematic diagram of the overall structure of a massage chair leg drive mechanism according to this utility model. Figure 6 yes Figure 1 The main view; Figure 7 yes Figure 1 Top view; Label Explanation: 1. Massage chair frame; 11. First crossbeam; 12. Second crossbeam; 13. Base frame; 14. Backrest frame; 2. Dual-axis output motor; 3. First transmission assembly; 31. First screw; 32. First threaded connector; 33. First nut seat; 4. Second transmission assembly; 41. Second screw; 42. Second nut seat; 5. First bearing housing; 6. Second bearing housing; 7. Left linkage mechanism; 71. First linkage; 711. First sleeve; 712. Second sleeve; 713. Locking element; 72. Second linkage; 8. Right linkage mechanism. Detailed Implementation

[0020] The present invention will be further described below with reference to the accompanying drawings and specific embodiments: Example 1 Please see Figures 1 to 7 As shown, this embodiment provides a massage chair leg drive mechanism, including a massage chair frame 1, a left leg support assembly, a right leg support assembly, a dual-axis output motor 2, a first transmission assembly 3, and a second transmission assembly 4.

[0021] The massage chair frame 1 is a welded steel or aluminum alloy frame used to support all components of the chair. The left leg support assembly and the right leg support assembly are respectively installed on the left and right sides of the massage chair frame 1 to support the user's left and right legs.

[0022] The dual-axis output motor 2 is a dual-output-shaft geared motor, with one output shaft extending from each of its left and right sides. The output shaft on the left side is connected to the left leg support assembly via the first transmission assembly 3; the output shaft on the right side is connected to the right leg support assembly via the second transmission assembly 4.

[0023] The first transmission assembly 3 includes a first screw 31 and a first threaded connector 32 fixedly sleeved on the first screw 31. The second transmission assembly 4 includes a second screw 41 and a second threaded connector fixedly sleeved on the second screw 41. The threads of the first threaded connector 32 and the second threaded connector have opposite directions of rotation. The two output shafts of the dual-axis output motor 2 simultaneously drive the two threaded connectors to rotate. Since the two threaded connectors have opposite directions of rotation, when the motor output shafts rotate in the same direction, the axial movement directions of the first screw 31 and the second screw 41 are opposite, thereby causing the left leg support assembly and the right leg support assembly to produce asynchronous movement.

[0024] This embodiment further defines the connection method between the nut seat and the leg support assembly. The first screw 31 is provided with a first nut seat 33 that mates with it. The internal thread of the first nut seat 33 matches the external thread of the first screw 31, allowing it to move axially along the screw. The first nut seat 33 is hinged to the corresponding left leg support assembly, specifically through a pin for rotational connection.

[0025] Similarly, a second nut seat 42 is provided on the second screw 41, and the second nut seat 42 is hinged to the right leg support assembly. When the screw rotates, the nut seat moves linearly along the screw and transmits thrust to the leg support assembly through the hinge point. The hinge design can automatically adapt to the angle changes of the leg support assembly during movement, avoiding jamming or additional bending moment caused by rigid connection, making the transmission smoother and the assembly simpler.

[0026] This embodiment describes in detail the specific motion conversion structure of the leg support assembly. The left leg support assembly includes a left leg bracket and a left linkage mechanism 7 hinged to the massage chair frame 1. The first nut seat 33 is hinged to one end of the left linkage mechanism 7, and the other end of the left linkage mechanism 7 is connected to the left leg bracket. The rotational motion of the first screw 31 is converted into the swinging motion of the left linkage mechanism 7 through the first nut seat 33, realizing the lifting or lowering motion of the left leg bracket.

[0027] The right leg support assembly similarly includes a right leg bracket and a right linkage mechanism 8. The second nut seat 42 is hinged to the right linkage mechanism 8 to drive the right leg bracket to move.

[0028] The linkage mechanism converts the linear motion of the nut seat into the arc-shaped swing of the leg support, a trajectory that better conforms to the natural flexion and extension curve of the human leg. Simultaneously, the linkage mechanism provides a certain leverage ratio, reducing the demand on the motor's output torque, resulting in smoother and gentler leg raising and lowering movements, avoiding abruptness.

[0029] This embodiment further defines the specific form of the linkage mechanism. The left linkage mechanism 7 is a two-bar linkage mechanism, including a first link 71 and a second link 72. One end of the first link 71 is hinged to the first nut seat 33, and the other end of the first link 71 is hinged to the middle of the second link 72. One end of the second link 72 is hinged to the massage chair frame 1, and the other end of the second link 72 is fixedly connected to the left leg support (which can be fixed by bolts or welding).

[0030] Similarly, the right linkage mechanism 8 is also a two-bar linkage with a symmetrical structure. When the nut seat moves back and forth, the first linkage 71 pushes the second linkage 72 to swing around its hinge point with the frame. The end of the second linkage 72 drives the leg support to make an arc motion. Because the second linkage 72 is subjected to force in the middle, its end swing angle is larger, achieving a larger leg lifting angle within a limited stroke. Moreover, the entire mechanism occupies little space, making it suitable for the compact layout inside a massage chair.

[0031] The specific implementation methods for adjusting and dynamically locking the length of the first link are as follows: In this embodiment, to achieve the complete dynamic process of "initial alignment → working misalignment → resetting alignment", only one of the first links in each of the left linkage mechanism 7 and the right linkage mechanism 8 is configured to be length-adjustable, while the other is not. The following explanation uses the example of the first link 71 in the left linkage mechanism 7 being a length-adjustable structure and the first link in the right linkage mechanism 8 being a fixed-length structure.

[0032] Specifically, the length-adjustable first connecting rod 71 includes a first sleeve 711, a second sleeve 712, and a locking member 713. The first sleeve 711 and the second sleeve 712 are nested together (for example, the second sleeve 712 is slidably inserted into the first sleeve 711). The locking member 713 is installed at the connection between the first sleeve 711 and the second sleeve 712 to lock the relative position between the first sleeve 711 and the second sleeve 712 after adjustment. The nested sleeve structure achieves length adjustment, which is simple in structure, low in cost, and easy to manufacture and assemble. The locking member reliably fixes the length after adjustment, ensuring the stability of the connecting rod's geometry during massage, preventing accidental extension or retraction due to force, and ensuring the reliable maintenance of the misaligned movement mode. In this embodiment, the locking member 713 is preferably a needle-type cylinder, whose direction of movement is perpendicular to the axis of the first sleeve or the second sleeve, to provide a stable and easily controllable locking force. The needle cylinder, used as a locking component, offers fast response and stable locking force. Its movement direction is perpendicular to the sleeve axis, effectively resisting tensile / compressive forces between the sleeves during locking and preventing slippage. The vertical locking method minimizes wear on the sleeve wall, thus extending the mechanism's service life.

[0033] To achieve precise automatic control, at least two position sensors (not shown in the figure) are provided on the first sleeve 711 or the second sleeve 712, respectively used to sense the relative positions of the first sleeve 711 and the second sleeve 712 in their two extreme states of full retraction and full extension. The two position sensors are electrically connected to the drive end of the locking member 713, and also electrically connected to the main controller of the massage chair. By automatically detecting the extreme positions of the sleeves (full retraction or full extension) through the position sensors and electrically connecting them to the locking member, automatic locking or unlocking can be achieved without manual intervention. This provides a precise detection and control basis for automatic locking during the "initial alignment → working misalignment" process and automatic unlocking during the "reset alignment" process, improving the intelligence and reset accuracy of the mechanism.

[0034] The complete working principle of this embodiment is as follows: Initial state (left and right aligned): Both the left and right leg support components are in their lowest positions (i.e., the leg supports are flat), aligned left and right. At this time, the first adjustable link 71 in the left linkage mechanism 7 is in the unlocked state (the needle cylinder is not locked), and its first sleeve 711 and second sleeve 712 can slide freely relative to each other and are in the fully retracted position (i.e., shortest length). The first link in the right linkage mechanism 8 is of fixed length. The dual-axis output motor 2 drives two screws, so that the first nut seat 33 corresponding to the left leg support component is located in the middle position of the screw (central assembly), while the second nut seat 42 corresponding to the right leg support component is located in the bottom position of the screw (bottom assembly).

[0035] Step 1 – Transition from Alignment to Misalignment (Single-Sided Stroke Self-Adaptation): The dual-axis output motor 2 starts, and the two screws rotate in the same direction. Due to the opposite screw threads, the first nut seat 33 and the second nut seat 42 move in opposite directions. Specifically, the first nut seat 33 moves towards the bottom of the screw, driving the left leg support assembly to rise; simultaneously, the second nut seat 42 moves towards the top of the screw, driving the right leg support assembly to descend. However, since the second nut seat 42 is initially at the bottom, the right leg support assembly on its side cannot descend further, so the right leg support assembly remains stationary. The left leg support assembly continues to rise under the drive of the first nut seat 33, simultaneously causing the first sleeve 711 and the second sleeve 712 of the first link 71 in the unlocked state of the left linkage mechanism 7 to slide relative to each other (relative movement of the sleeves) to absorb this difference in movement. When the first nut seat 33 reaches the bottom of the screw, the left leg support assembly rises to its highest point, at which point the left leg has formed a clear misalignment with the right leg (one high and one low).

[0036] Step Two – Locking the Misalignment Reference: When the left leg support assembly rises to its highest point, and the position sensor detects that the first sleeve 711 and the second sleeve 712 have slid relative to each other to their fully extended state (i.e., at their longest length), the controller issues a command to activate the needle cylinder (locking element 713) to lock the relative position of the first sleeve 711 and the second sleeve 712. At this time, the first link 71 of the left linkage mechanism 7 is fixed to a new, longer length, and the misalignment state of the left and right leg support assemblies is mechanically locked.

[0037] Step 3 – Maintaining the Asynchronous Movement with Misalignment: The dual-axis output motor 2 switches its rotation direction (enters normal operating mode). At this time, the needle cylinder remains locked, and the length of the first connecting rod 71 no longer changes. The two nut seats begin to move in opposite directions (the first nut seat 33 moves towards the top of the screw, and the second nut seat 42 moves towards the bottom of the screw). Since the geometric length of the left connecting rod mechanism 7 has been locked and changed, under the same nut seat stroke, the left leg support assembly and the right leg support assembly will exhibit a stable asynchronous movement with misalignment (e.g., one side rises at a greater angle than the other, or one side rises while the other side falls but the amplitude is asymmetrical), thereby simulating more natural and asymmetrical leg interaction movements, such as walking and pedaling.

[0038] Step 4 – Resetting Alignment (Returning from Misalignment to Alignment): When it is time to end the massage and reset, the dual-axis output motor 2 continues to rotate in the direction that lowers the legs (i.e., maintaining the direction of rotation in Step 3). During this process, the needle cylinder remains locked, and the left and right leg support components remain misaligned and descend synchronously. When the position sensor detects that the left leg support component (i.e., the side that was previously length-adjusted) has descended to its lowest position first, the controller issues a command, the needle cylinder opens, and the first sleeve 711 and the second sleeve 712 are unlocked. The first connecting rod 71 then automatically retracts to its fully retracted state under the action of gravity or spring force (if any). Subsequently, the dual-axis output motor 2 continues to drive a short distance, causing the right leg support component to also descend to its lowest position. At the same time, the first nut seat 33 returns to the center position, and the second nut seat 42 returns to the bottom position. At this point, the entire mechanism has completely returned to its initial aligned state (both legs are at the bottom, and the first connecting rod has returned to its shortest length), ready for the next start.

[0039] Through the above-described process, this embodiment achieves a complete dynamic process of "initial alignment → working misalignment → resetting alignment" under single-motor drive. It automatically completes the misalignment adaptation at the start of each massage, maintains stable asymmetrical movement during the massage, and reliably resets to a left-right aligned state after the massage ends. The entire process requires no manual intervention from the user, is simple to control, and has high reset accuracy, effectively solving the problems of difficult reset or initial inability to align in existing technologies.

[0040] Example 2 Based on Embodiment 1, this embodiment optimizes the support structure of the frame and screw. The massage chair frame 1 includes a first crossbeam 11 and a second crossbeam 12. The first crossbeam 11 is closer to the leg support component than the second crossbeam 12 (i.e., the first crossbeam 11 is located on the side closer to the user's legs, and the second crossbeam 12 is located on the side farther from the legs). One end of the first screw 31 is mounted on the first crossbeam 11 via a first bearing seat 5, and the other end of the first screw 31 is mounted on the second crossbeam 12 via a second bearing seat 6. Similarly, the second screw 41 is also mounted on the first crossbeam 11 and the second crossbeam 12 via two bearing seats.

[0041] This two-end support structure can effectively withstand the bending moment and radial force generated by the rotation of the screw and axial load, preventing the screw from bending and deforming during long-term use, thus improving transmission accuracy and service life. At the same time, since both left and right screws are mounted on the same pair of crossbeams, parallelism and horizontality are ensured, making the movement of the left and right leg support components more stable and reliable.

[0042] Example 3 This embodiment optimizes the overall layout. The first transmission assembly 3 and the second transmission assembly 4 are arranged parallel to each other and horizontally spaced apart, with space between them. The dual-axis output motor 2 is located between the first transmission assembly 3 and the second transmission assembly 4, that is, the dual-axis output motor 2 is located in the middle of the two left and right screws.

[0043] This symmetrical arrangement ensures even force distribution on both sides, preventing additional torsion caused by unilateral force on the frame. Simultaneously, centering the motor shortens the distance between the two output shafts and their corresponding transmission components, reducing energy loss and torsional elastic deformation caused by long shaft transmissions. The overall structure is balanced, aesthetically pleasing, and facilitates installation and maintenance.

[0044] Example 4 This embodiment discloses a compact motor mounting method. A bearing component is fitted onto each screw (e.g., the first screw 31 and the second screw 41), and this bearing component can be a deep groove ball bearing or a sliding bearing. The housing of the dual-shaft output motor 2 is mounted on the bearing component via a bracket or directly, meaning that the left and right sides of the motor housing are fixedly connected to the outer rings of the bearing components on the two screws, respectively.

[0045] In this way, the motor not only provides power but also serves as an intermediate auxiliary support point for the screw, sharing part of the load on the bearing housing and improving the screw's bending stiffness. Simultaneously, the relative position of the motor housing and the screw is directly fixed, eliminating the need for an additional motor mounting bracket, reducing the number of parts and manufacturing costs, and making the entire machine more compact.

[0046] Example 5 In this embodiment, the tilt angle of the screw is set. Both the first screw 31 and the second screw 41 are tilted, specifically: the end of the screw closer to the leg support assembly (i.e., the end closer to the first crossbeam 11) is higher than the end of the screw farther from the leg support assembly (i.e., the end closer to the second crossbeam 12). The bearing is located on the end of the screw farther from the leg support assembly, i.e., the lower end position.

[0047] The inclined arrangement has the following advantages: When the motor stops driving, the nut seat will automatically slide to the lower end (the end away from the legs) under the action of gravity, thereby assisting the leg support to descend and reducing the load and energy consumption when the motor reverses. At the same time, the bearings at the lower end bear the main axial force, which is conducive to the return of lubricating oil or grease to the threaded pair under the action of gravity, improving lubrication conditions and extending the service life of the transmission components.

[0048] Example 6 This embodiment is described in conjunction with the overall frame of the massage chair. The massage chair frame 1 includes a base frame 13 and a backrest frame 14 hinged to the base frame 13 (the backrest frame 14 can rotate relative to the base frame 13 to achieve backrest angle adjustment). The leg drive mechanism (including a dual-axis output motor 2, a first transmission component 3, and a second transmission component 4) is installed on one side of the base frame 13.

[0049] By installing the leg drive mechanism independently from the backrest frame 14, leg movements and backrest angle adjustment are decoupled. Users can independently control leg lifting without affecting the backrest posture, or coordinate with the backrest for a full-body massage (e.g., lifting the legs while the backrest reclines to simulate a zero-gravity posture). The base frame 13 serves as a fixed foundation, providing a stable mounting platform for screws, motors, etc., avoiding movement interference.

[0050] Example 7 This embodiment further integrates the internal layout. The dual-axis output motor 2, the first transmission assembly 3, and the second transmission assembly 4 are respectively disposed inside the base frame 13. Specifically, the base frame 13 has a hollow structure or is formed by a U-shaped steel beam enclosing an internal cavity, in which all the aforementioned components are housed.

[0051] The benefits of this design are: it makes full use of the unused space inside the base, resulting in a clean and simple appearance with no exposed moving parts, thus improving safety—preventing users' feet or foreign objects from getting caught in the screws or linkages and causing injury. At the same time, the built-in structure lowers the center of gravity, increasing the massage chair's stability and facilitating standardized wiring, dust prevention, and noise reduction, thereby enhancing product quality and user experience.

[0052] This utility model has been described with reference to the above-described embodiments and accompanying drawings. However, the above embodiments are merely examples for implementing this utility model. It must be noted that the disclosed embodiments do not limit the scope of this utility model. On the contrary, modifications and equivalent provisions included in the spirit and scope of the claims are all included within the scope of this utility model.

Claims

1. A leg drive mechanism for a massage chair, comprising a massage chair frame and a left leg support assembly and a right leg support assembly respectively mounted on the massage chair frame, characterized in that, It also includes a dual-axis output motor, a first transmission assembly, and a second transmission assembly; One output shaft of the dual-axis output motor is connected to the left leg support assembly via the first transmission assembly; The other output shaft of the dual-axis output motor is connected to the right leg support assembly via the second transmission assembly; The first transmission assembly and the second transmission assembly each include a screw and a threaded connector fixedly sleeved on the screw. The threaded connectors of the first transmission assembly and the second transmission assembly have opposite thread directions. The two output shafts of the dual-axis output motor simultaneously drive the two threaded connectors. The two screws respectively drive the left leg support assembly and the right leg support assembly, causing the left leg support assembly and the right leg support assembly to produce asynchronous motion. The screw is provided with a nut seat that mates with it. The nut seat is hinged to the corresponding left leg support assembly or right leg support assembly. The left leg support assembly and the right leg support assembly each include a leg bracket and a linkage mechanism hinged to the massage chair frame. The nut seat is hinged to one end of the linkage mechanism, and the other end of the linkage mechanism is connected to the leg bracket. The linkage mechanism is a two-bar linkage, which includes a first link and a second link. One end of the first link is hinged to a nut seat, and the other end of the first link is hinged to the middle of the second link. One end of the second link is hinged to the massage chair frame, and the other end of the second link is fixedly connected to the leg support. One of the two first links is configured to be length-adjustable, and the other of the two first links is configured to be length-non-adjustable. The length-adjustable first connecting rod includes a first sleeve, a second sleeve, and a locking element. The first sleeve and the second sleeve are nested together, and the locking element is installed at the connection between the first sleeve and the second sleeve and is used to lock the relative position between the first sleeve and the second sleeve. The first sleeve or the second sleeve is provided with at least two position sensors, which are used to sense the relative positions of the first sleeve and the second sleeve in two states: when they are in a contracted state and when they are in an expanded state. The two position sensors are electrically connected to the drive end of the locking member.

2. The massage chair leg drive mechanism according to claim 1, characterized in that, The locking component is a needle cylinder, and the direction of movement of the needle cylinder is perpendicular to the axis of the first sleeve or the second sleeve.

3. The massage chair leg drive mechanism according to claim 1, characterized in that, The massage chair frame includes a first crossbeam and a second crossbeam. The first crossbeam is positioned closer to the leg support component than the second crossbeam. One end of the screw is mounted on the first crossbeam via a bearing seat, and the other end of the screw is mounted on the second crossbeam via another bearing seat.

4. The massage chair leg drive mechanism according to claim 1, characterized in that, The first transmission component and the second transmission component are arranged parallel to each other and horizontally spaced apart, and the dual-axis output motor is located between the first transmission component and the second transmission component.

5. The massage chair leg drive mechanism according to claim 4, characterized in that, The screw is fitted with a bearing, and the housing of the dual-shaft output motor is fitted onto the bearing.

6. The massage chair leg drive mechanism according to claim 5, characterized in that, The screw is inclined, with one end of the screw near the leg support assembly being higher than the other end of the screw away from the leg support assembly, and the bearing is located on the end of the screw away from the leg support assembly.

7. The massage chair leg drive mechanism according to claim 1, characterized in that, The massage chair frame includes a base frame and a backrest frame hinged to the base frame, and the leg drive mechanism is mounted on one side of the base frame.

8. The massage chair leg drive mechanism according to claim 7, characterized in that, The dual-axis output motor, the first transmission component, and the second transmission component are respectively disposed inside the base frame.

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