Massage chair leg asynchronous lifting and falling driving structure

Abstract

The utility model relates to massage chair technical field, more particularly, relate to a massage chair chair leg asynchronous lifting drive structure. Through single drive motor, bevel gear drive mechanism, incomplete gear assembly, the sliding block assembly of rack and the collaborative cooperation of connecting rod mechanism, realized two chair leg assembly's asynchronous lifting movement. This structure only needs a power source to drive both sides chair leg alternate lifting, has reduced manufacturing cost and energy consumption significantly. Meanwhile, asynchronous lifting is more in line with the leg alternate power habit of human natural sitting, has improved user's comfortable feeling and the convenience of getting on and off massage chair. Besides, whole transmission chain structure is compact, transmission efficiency is high, and utilizes the intermittent characteristic of incomplete gear, has guaranteed the accuracy and stability of asynchronous action.

Description

Technical Field

[0001] This utility model relates to the field of massage chair technology, and more specifically, to an asynchronous lifting and lowering drive structure for massage chair legs. Background Technology

[0002] With the improvement of people's living standards, massage chairs, as a health and wellness device, have been widely used in homes, hotels, and business lounges. To improve the ease of getting in and out of the chair and enhance user comfort, modern massage chairs are usually equipped with a leg raising and lowering function, allowing the chair legs to automatically raise or lower when the user is about to get in or out of the massage chair, avoiding the need for the user to bend over or strain to lift their legs.

[0003] Most existing massage chairs use two independent motors to drive the left and right legs respectively, or a single motor to drive both legs simultaneously via a synchronous transmission mechanism. However, these existing technologies have the following shortcomings: First, while the dual-motor solution offers flexible control, it is more expensive, has complex control logic, and it is difficult to guarantee the synchronization between the two motors. Second, while the single-motor synchronous drive solution is cheaper, the two legs always move synchronously, which does not conform to the human body's natural habit of alternating leg movements when sitting up. Users are prone to discomfort during the lifting process, and the center of gravity shifts drastically during synchronous lifting, reducing comfort and safety.

[0004] Therefore, how to provide a drive structure that is compact, low-cost, and can achieve asynchronous lifting and lowering of chair legs is a technical problem that urgently needs to be solved by those skilled in the art. Utility Model Content

[0005] The purpose of this invention is to overcome the shortcomings of the prior art and provide an asynchronous lifting and lowering drive structure for massage chair legs. This structure only requires a single drive motor to realize the alternating and asynchronous lifting and lowering movement of the two chair legs, which is more ergonomic, compact in structure and reliable in transmission.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] An asynchronous lifting and lowering drive structure for massage chair legs includes a base frame and chair leg assemblies, a drive motor, a bevel gear transmission mechanism, an incomplete gear assembly, a slider assembly with a rack and pinion, and a linkage mechanism, all respectively mounted on the base frame.

[0008] The output shaft of the drive motor is connected to the input end of the bevel gear transmission mechanism. The bevel gear transmission mechanism includes two output ends that rotate in opposite directions, and the two output ends that rotate in opposite directions respectively mesh with the two incomplete gear assemblies.

[0009] Each of the incomplete gear assemblies engages with a rack-and-pinion slider assembly, which is slidably disposed within a groove in the base frame; the slider assembly is hinged to the chair leg assembly via a linkage mechanism.

[0010] The drive motor drives the two chair leg assemblies to achieve asynchronous lifting and lowering movements through a transmission chain consisting of a bevel gear transmission mechanism, an incomplete gear assembly, a slider assembly, and a linkage mechanism.

[0011] Furthermore, the bevel gear transmission mechanism includes two driven gears and two bevel gear assemblies. The two driven gears are distributed on both horizontal sides of the output shaft of the drive motor and are respectively connected to the output shaft of the drive motor. Each driven gear is connected to an incomplete gear assembly through a bevel gear assembly.

[0012] Furthermore, the bevel gear assembly includes a first bevel gear and a second bevel gear that mesh with each other. The driven gear meshes with the first bevel gear. The incomplete gear assembly is fixedly mounted on the output shaft of the second bevel gear. The tooth distribution angle of the incomplete gear assembly is less than 360°, and the tooth distribution phase difference between the two incomplete gears is 180°.

[0013] Furthermore, the rack-and-tooth slider assembly includes a ring-shaped slider body and two racks disposed on the slider body. The slider body includes two straight segments and two arc segments. The two straight segments are arranged in parallel vertically. The two arc segments are respectively connected to the same side ends of the two straight segments. The two racks are respectively disposed on the opposite surfaces of the two straight segments. The incomplete gear assembly meshes with the racks on the slider body.

[0014] The two straight segments are provided with strip-shaped protrusions on their opposing surfaces. The base frame has a strip-shaped slide groove. The strip-shaped protrusions cooperate with the strip-shaped slide groove. When the incomplete gear assembly is driven, it drives the slider body to reciprocate linearly along the strip-shaped slide groove of the base frame.

[0015] Furthermore, the linkage mechanism includes a first link and a second link. One end of the first link is hinged to the slider body, 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 base frame, and the other end of the second link is hinged to the bottom of the chair leg assembly.

[0016] Furthermore, it also includes a limiting member, which includes a limiting body and two connecting arms extending outward from opposite ends of the limiting body. The limiting body and the two connecting arms together form a receiving space that can accommodate the incomplete gear assembly. The limiting body is provided with a through hole for the output shaft of the second bevel gear to pass through. The incomplete gear assembly and the second bevel gear are respectively disposed on both sides of the limiting body. The two connecting arms are respectively fixedly connected to the base frame.

[0017] Furthermore, the effective meshing angle of the gear teeth in the incomplete gear assembly is 120°-180°, and the gear tooth module matches the module of the rack on the slider assembly.

[0018] Furthermore, it also includes a reduction gearbox, through which the output shaft of the drive motor is connected to the input end of the bevel gear transmission mechanism.

[0019] Furthermore, the reduction gearbox is a worm gear reducer, and the drive motor is a DC geared motor.

[0020] Compared with the prior art, this utility model has the following advantages:

[0021] This utility model provides an asynchronous lifting and lowering drive structure for massage chair legs. Through the coordinated operation of a single drive motor, a bevel gear transmission mechanism, an incomplete gear assembly, a rack-and-pinion slider assembly, and a linkage mechanism, it achieves asynchronous lifting and lowering motion of two chair leg assemblies. This structure requires only one power source to drive the alternating lifting and lowering of both chair legs, significantly reducing manufacturing costs and energy consumption. Simultaneously, asynchronous lifting and lowering better conforms to the alternating leg force exertion habit of the human body when naturally sitting up, improving user comfort and the convenience of getting on and off the massage chair. Furthermore, the entire transmission chain structure is compact, has high transmission efficiency, and utilizes the intermittent characteristics of incomplete gears to ensure the accuracy and stability of asynchronous movements. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the overall structure of an asynchronous lifting and lowering drive structure for the legs of a massage chair according to this utility model.

[0023] Figure 2 yes Figure 1 The main view;

[0024] Figure 3 yes Figure 1 Top view;

[0025] Figure 4 yes Figure 1 Side view;

[0026] Figure 5 This is a partial structural diagram of an asynchronous lifting and lowering drive structure for the legs of a massage chair according to this utility model;

[0027] Figure 6 yes Figure 5 The main view;

[0028] Figure 7 yes Figure 5 Top view;

[0029] Figure 8 yes Figure 5 Side view;

[0030] Figure 9 This is a schematic diagram of the bevel gear transmission mechanism, incomplete gear assembly, and slider assembly of an asynchronous lifting and lowering drive structure for the legs of a massage chair according to this utility model.

[0031] Figure 10 yes Figure 9 Top view;

[0032] Figure 11 yes Figure 9 Side view;

[0033] Figure 12 This is an exploded view of the incomplete gear assembly and slider assembly of the asynchronous lifting and lowering drive structure for the legs of a massage chair according to this utility model.

[0034] Figure 13 This is an exploded structural diagram of the incomplete gear assembly and slider assembly of the asynchronous lifting and lowering drive structure of the massage chair legs according to this utility model.

[0035] Label Explanation:

[0036] 1. Base frame; 11. Strip slide; 12. Crossbeam;

[0037] 2. Chair leg assembly;

[0038] 3. Drive motor;

[0039] 4. Bevel gear transmission mechanism; 41. Driven gear; 42. Bevel gear assembly; 421. First bevel gear; 422. Second bevel gear;

[0040] 5. Incomplete gear assembly;

[0041] 6. Slider assembly; 61. Slider body; 611. Straight segment; 612. Arc segment; 62. Rack; 63. Strip-shaped protrusion;

[0042] 7. Linkage mechanism; 71. First link; 72. Second link;

[0043] 8. Limiting component; 81. Limiting body; 82. Connecting arm; 83. Through hole. Detailed Implementation

[0044] The present invention will be further described below with reference to the accompanying drawings and specific embodiments:

[0045] This utility model provides an asynchronous lifting and lowering drive structure for massage chair legs, including a base frame and chair leg assemblies, a drive motor, a bevel gear transmission mechanism, an incomplete gear assembly, a slider assembly with a rack and pinion, and a linkage mechanism respectively mounted on the base frame.

[0046] The output shaft of the drive motor is connected to the input end of the bevel gear transmission mechanism. The bevel gear transmission mechanism includes two output ends that rotate in opposite directions, and the two output ends that rotate in opposite directions respectively mesh with the two incomplete gear assemblies.

[0047] Each of the incomplete gear assemblies engages with a rack-and-pinion slider assembly, which is slidably disposed within a groove in the base frame; the slider assembly is hinged to the chair leg assembly via a linkage mechanism.

[0048] The drive motor drives the two chair leg assemblies to achieve asynchronous lifting and lowering movements through a transmission chain consisting of a bevel gear transmission mechanism, an incomplete gear assembly, a slider assembly, and a linkage mechanism.

[0049] Compared with the prior art, this utility model has the following advantages:

[0050] This utility model provides an asynchronous lifting and lowering drive structure for massage chair legs. Through the coordinated operation of a single drive motor, a bevel gear transmission mechanism, an incomplete gear assembly, a rack-and-pinion slider assembly, and a linkage mechanism, it achieves asynchronous lifting and lowering motion of two chair leg assemblies. This structure requires only one power source to drive the alternating lifting and lowering of both chair legs, significantly reducing manufacturing costs and energy consumption. Simultaneously, asynchronous lifting and lowering better conforms to the alternating leg force exertion habit of the human body when naturally sitting up, improving user comfort and the convenience of getting on and off the massage chair. Furthermore, the entire transmission chain structure is compact, has high transmission efficiency, and utilizes the intermittent characteristics of incomplete gears to ensure the accuracy and stability of asynchronous movements.

[0051] Furthermore, the bevel gear transmission mechanism includes two driven gears and two bevel gear assemblies. The two driven gears are distributed on both horizontal sides of the output shaft of the drive motor and are respectively connected to the output shaft of the drive motor. Each driven gear is connected to an incomplete gear assembly through a bevel gear assembly.

[0052] As described above, by defining the specific structure of the bevel gear transmission mechanism (including two driven gears and two bevel gear assemblies), power splitting and steering conversion on both sides of the drive motor output shaft are achieved. This layout allows the rotational motion of the motor output shaft to be smoothly and efficiently transmitted to the incomplete gear assemblies arranged on both sides, ensuring the symmetry and independence of the transmission paths on both sides. The two driven gears are directly connected to the motor output shaft, reducing intermediate transmission links, improving transmission accuracy and response speed, and providing a precise power foundation for subsequent asynchronous actions.

[0053] Furthermore, the bevel gear assembly includes a first bevel gear and a second bevel gear that mesh with each other. The driven gear meshes with the first bevel gear. The incomplete gear assembly is fixedly mounted on the output shaft of the second bevel gear. The tooth distribution angle of the incomplete gear assembly is less than 360°, and the tooth distribution phase difference between the two incomplete gears is 180°.

[0054] As described above, the bevel gear assembly (first and second bevel gears meshing) provides reliable orthogonal shaft transmission, enabling power to be converted from horizontal to vertical output, facilitating flexible arrangement within the limited space of the massage chair base. Specifically, setting the phase difference of the tooth distribution of the two incomplete gears to 180° is the core key to achieving "asynchronous" lifting and lowering. When one incomplete gear engages to drive the slider assembly, the other side is in a disengaged, stationary, or reset state, ensuring an alternating lifting and lowering cycle for both chair legs, avoiding motion interference and ensuring smooth and natural movement transitions.

[0055] Furthermore, the rack-and-tooth slider assembly includes a ring-shaped slider body and two racks disposed on the slider body. The slider body includes two straight segments and two arc segments. The two straight segments are arranged in parallel vertically. The two arc segments are respectively connected to the same side ends of the two straight segments. The two racks are respectively disposed on the opposite surfaces of the two straight segments. The incomplete gear assembly meshes with the racks on the slider body.

[0056] The two straight segments are provided with strip-shaped protrusions on their opposing surfaces. The base frame has a strip-shaped slide groove. The strip-shaped protrusions cooperate with the strip-shaped slide groove. When the incomplete gear assembly is driven, it drives the slider body to reciprocate linearly along the strip-shaped slide groove of the base frame.

[0057] As described above, the unique annular slider body and its double rack structure ensure that the incomplete gear always meshes with one of the racks during rotation, achieving continuous reciprocating linear motion. This avoids the drawbacks of traditional single rack mechanisms that require a return spring or additional reset mechanism. The racks on the opposing surfaces of the two linear segments, combined with the forward and reverse rotation of the incomplete gear, drive the slider to smoothly change direction. The cooperation between the strip-shaped convex ribs and strip-shaped grooves provides precise linear guidance and support for the slider, effectively suppressing wobbling or deflection during operation, ensuring transmission stability and positional accuracy, and extending service life.

[0058] Furthermore, the linkage mechanism includes a first link and a second link. One end of the first link is hinged to the slider body, 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 base frame, and the other end of the second link is hinged to the bottom of the chair leg assembly.

[0059] As described above, the double-hinged linkage mechanism, consisting of the first and second links, efficiently converts the reciprocating linear motion of the slider into the lifting or lowering rotational motion of the chair leg assembly. This linkage structure has a motion amplification effect, allowing for a larger lifting angle of the chair legs using a smaller stroke of the slider. Simultaneously, the hinged connection reduces friction and wear on the moving parts, resulting in a smooth and reliable motion trajectory. One end of the second link is hinged to the base frame to form a fixed fulcrum, while the other end pushes the bottom of the chair leg. This arrangement gives the chair leg a self-locking tendency when raised to its highest point, improving safety during use.

[0060] Furthermore, it also includes a limiting member, which includes a limiting body and two connecting arms extending outward from opposite ends of the limiting body. The limiting body and the two connecting arms together form a receiving space that can accommodate the incomplete gear assembly. The limiting body is provided with a through hole for the output shaft of the second bevel gear to pass through. The incomplete gear assembly and the second bevel gear are respectively disposed on both sides of the limiting body. The two connecting arms are respectively fixedly connected to the base frame.

[0061] As described above, the added limiting component provides a stable installation and positioning space for the incomplete gear assembly. The receiving space formed by the limiting body and its two connecting arms can precisely limit the axial movement and radial runout of the incomplete gear assembly, ensuring that it always maintains the correct meshing position with the rack on the slider. The through hole allows the output shaft of the second bevel gear to pass through, making the entire transmission assembly a modular unit, facilitating assembly and maintenance. This structure effectively prevents the incomplete gear from dislodging or shifting during high-speed rotation or load changes, significantly improving the reliability and durability of the transmission system.

[0062] Furthermore, the effective meshing angle of the gear teeth in the incomplete gear assembly is 120°-180°, and the gear tooth module matches the module of the rack on the slider assembly.

[0063] As described above, limiting the effective meshing angle of the incomplete gear teeth to 120°-180° ensures sufficient drive stroke for the chair legs to complete the raising and lowering action, while avoiding unclear asynchronous switching or motion interference caused by an excessively large meshing angle. This angle range matches the slider stroke and the chair leg raising angle, allowing the motor to continuously transmit power for most of the working time, thus improving efficiency. Simultaneously, matching the gear tooth module with the slider rack module ensures smooth meshing, sufficient load-bearing capacity, reduces tooth surface wear and noise, and extends the service life of the gear pair.

[0064] Furthermore, it also includes a reduction gearbox, through which the output shaft of the drive motor is connected to the input end of the bevel gear transmission mechanism.

[0065] As described above, adding a reduction gearbox between the drive motor and the bevel gear transmission mechanism reduces the motor's output speed and increases its output torque, thereby providing a stronger driving force to overcome the load on the chair legs and the user's legs. The addition of the reduction gearbox allows for the selection of a higher-speed, lower-torque micro motor, reducing motor cost and size. Simultaneously, the deceleration process smooths the power output, reducing impact and vibration, making the raising and lowering of the chair legs slower, gentler, and quieter, thus improving the user experience.

[0066] Furthermore, the reduction gearbox is a worm gear reducer, and the drive motor is a DC geared motor.

[0067] As described above, the combination of a worm gear reducer and a DC geared motor offers multiple advantages: the worm gear reducer has a self-locking characteristic, ensuring the chair legs reliably maintain their position at any elevation angle when the motor stops rotating, preventing them from falling due to gravity and significantly improving safety. The DC geared motor features high starting torque, simple control, and convenient speed adjustment, facilitating precise position adjustment of the chair legs through simple forward / reverse rotation or PWM control. The overall solution achieves a low-noise, high-torque, self-locking, reliable, and cost-effective drive system, making it ideal for home appliances like massage chairs that require frequent start-stop and safety positioning.

[0068] Example 1

[0069] Please see Figures 1 to 13This embodiment provides an asynchronous lifting and lowering drive structure for massage chair legs, particularly suitable for high-end massage chairs that need to simulate the natural sitting and standing movements of the human body. The structure mainly includes: a base frame 1, two left and right leg assemblies 2, a drive motor 3, a bevel gear transmission mechanism 4, two incomplete gear assemblies 5, two rack-and-pinion slider assemblies 6, and two sets of linkage mechanisms 7. All components are symmetrically or correspondingly arranged on the left and right sides of the base frame 1.

[0070] The base frame 1 includes multiple crossbeams 12, which together form a load-bearing structure. The drive motor 3 and the bevel gear transmission mechanism 4 are respectively mounted on the load-bearing structure.

[0071] The output shaft of the drive motor 3 is first connected to a reduction gearbox. In this embodiment, the reduction gearbox is preferably a worm gear reducer, and the drive motor 3 is a DC geared motor. Because the worm gear reducer has a self-locking characteristic, when the drive motor 3 stops operating, the chair leg assembly 2 can reliably maintain any raised angle and will not fall due to the weight of the person or the component itself, greatly improving safety. At the same time, the DC geared motor has the advantages of high starting torque, simple control, and convenient speed adjustment, facilitating precise adjustment of the chair leg position through simple forward / reverse control or PWM speed regulation.

[0072] The output shaft of the drive motor 3, after being reduced in speed and torque by the gearbox, is connected to the input end of the bevel gear transmission mechanism 4. Specifically, the bevel gear transmission mechanism 4 includes two driven gears 41 (i.e., a left driven gear and a right driven gear) and two bevel gear assemblies 42. The two driven gears 41 are symmetrically distributed on both sides of the output shaft of the drive motor 3 (or the output shaft of the gearbox) and mesh with the output shaft respectively, thereby obtaining rotational power in opposite directions. Each driven gear 41 then transmits power to the corresponding incomplete gear assembly 5 through a bevel gear assembly 42.

[0073] More specifically, each of the bevel gear assemblies 42 includes a first bevel gear 421 and a second bevel gear 422 that mesh with each other. The driven gear 41 meshes with the first bevel gear 421, which then transmits power orthogonally to the second bevel gear 422. The incomplete gear assembly 5 is fixedly mounted on the output shaft of the second bevel gear 422. Through this series of transmissions, the rotational motion of the drive motor 3 is split into left and right sides with opposite directions, and changed to an axial direction suitable for driving the incomplete gear assembly 5.

[0074] As the core components for asynchronous lifting and lowering, the two incomplete gear assemblies 5 have essentially the same structure, but their tooth distribution phases differ significantly. Specifically, the tooth distribution angle of each incomplete gear assembly 5 is less than 360° (i.e., not a complete spur gear), and the tooth distribution phase difference between the two incomplete gear assemblies 5 is 180°. For example, when the first tooth of the left incomplete gear assembly 5 is in the initial meshing position, the first tooth of the right incomplete gear assembly 5 is exactly in the disengagement position or 180° out of phase. This design ensures that when the left incomplete gear enters the meshing zone and drives its corresponding slider assembly 6 to move, the right incomplete gear is exactly in the toothless idle stroke segment, and its corresponding slider assembly 6 is in a stationary or reset state, and vice versa, thus achieving strictly alternating lifting and lowering of the two chair leg assemblies 2.

[0075] The rack-and-pinion slider assembly 6 includes a ring-shaped slider body 61 and two racks 62. The slider body 61 is integrally formed by two parallel straight segments 611 and arc segments 612 at the left and right ends, forming an oval or rectangular rounded-corner ring. The two racks 62 are respectively mounted (or integrally formed) on the opposite surfaces of the two straight segments 611, namely the lower surface of the upper straight segment and the upper surface of the lower straight segment. The teeth of the two racks 62 are arranged oppositely and match the teeth of the incomplete gear assembly 5. This unique ring-shaped double rack structure allows the incomplete gear assembly 5 to mesh with the upper and lower racks sequentially when rotating continuously in one direction, thereby driving the slider body 61 to move linearly to one side first. After the incomplete gear has rotated half a turn, it drives the slider body 61 to move linearly in the opposite direction, achieving continuous reciprocating motion without a reversing mechanism. At the same time, this structure eliminates the need for a return spring or additional reset mechanism required by traditional single racks, simplifying the overall design.

[0076] To ensure sliding guidance accuracy, strip-shaped protrusions 63 are provided on the back surfaces of the two straight segments 611 (i.e., the upper surface of the upper straight segment and the lower surface of the lower straight segment). A corresponding strip-shaped groove 11 is provided on the base frame 1. The strip-shaped protrusions 63 are embedded in the strip-shaped grooves 11, forming a sliding fit. When the incomplete gear assembly 5 is driven to rotate, its teeth mesh with the rack 62 on the slider body 61, driving the slider body 61 to perform precise and stable reciprocating linear motion along the strip-shaped groove 11 of the base frame 1. The cooperation between the strip-shaped protrusions 63 and the strip-shaped groove 11 effectively suppresses wobbling or deflection of the slider during operation.

[0077] The linkage mechanism 7 includes a first link 71 and a second link 72. One end of the first link 71 is hinged to the upper end of the slider body 61, and the other end of the first link 71 is hinged to the middle (near the midpoint) of the second link 72. One end of the second link 72 is hinged to the base frame 1 via a fixed hinge support, forming a swing fulcrum, and the other end of the second link 72 is hinged to the chair leg assembly 2. When the slider body 61 performs reciprocating linear motion, it pulls the first link 71, which in turn pushes the second link 72 to swing around its hinge point with the base frame 1, thereby efficiently converting the linear motion of the slider body 61 into the lifting or lowering rotational motion of the chair leg assembly 2. This linkage mechanism 7 has a certain motion amplification effect, that is, a relatively small stroke of the slider body 61 can achieve a large lifting angle of the chair legs.

[0078] To prevent the incomplete gear assembly 5 from axial movement or radial runout during high-speed rotation or under load impact, which could affect its proper meshing with the rack 62, this embodiment preferably also includes a limiting member 8. The limiting member 8 comprises a plate-shaped limiting body 81 and two connecting arms 82 extending outward from opposite ends of the limiting body 81. The limiting body 81 and the two connecting arms 82 together form an approximately U-shaped or C-shaped receiving space, within which the incomplete gear assembly 5 is housed, with its gear teeth extending from the open side to mesh with the rack 62. A through hole 83 is provided at the center of the limiting body 81, through which the output shaft of the second bevel gear 422 passes before being fixedly connected to the incomplete gear assembly 5. After assembly, the incomplete gear assembly 5 and the second bevel gear 422 are located on either side of the limiting body 81, and the two connecting arms 82 are fixedly connected to the base frame 1 by screws or welding. The limiting component 8 not only provides precise installation positioning for the incomplete gear assembly 5, but also restricts its axial and radial degrees of freedom, effectively preventing tooth stripping and uneven wear, and significantly improving the reliability and service life of the transmission system.

[0079] As a further preferred embodiment, the effective meshing angle of the teeth in the incomplete gear assembly 5 (i.e., the range of angles in which the teeth are continuously distributed on the circumference) is set to 120° to 180°. This angle range has been verified in practice: if the angle is less than 120°, the stroke of the drive slider body 61 is insufficient, resulting in insufficient lifting angle of the chair leg assembly 2; if the angle is greater than 180°, overlapping meshing areas will occur during the alternating switching of the left and right incomplete gear assemblies 5, affecting the clarity of the asynchronous effect. At the same time, the module of the teeth is precisely matched with the module of the rack on the slider assembly 6 to ensure smooth meshing, sufficient load-bearing capacity, and reduced operating noise.

[0080] The work process is briefly described as follows:

[0081] When the drive motor 3 rotates forward through the reduction gearbox, the power is split into left and right rotational outputs via the bevel gear transmission mechanism 4, with opposite rotational directions on both sides. Since the phase difference between the teeth of the two incomplete gear assemblies 5 is 180°, assuming that the left incomplete gear assembly 5 is currently engaged with the rack on the left slider assembly 6, while the right incomplete gear assembly 5 is in a toothless idle zone, the left incomplete gear assembly 5 drives the left slider assembly 6 to move linearly backward (or forward), pulling the left chair leg assembly 2 upward (or downward) via the left linkage mechanism 7. Simultaneously, the right slider assembly 6 and chair leg assembly 2 remain stationary or in a lowered reset state. When the drive motor 3 continues to rotate until the teeth of the left incomplete gear assembly 5 disengage, the teeth of the right incomplete gear assembly 5 engage, driving the right slider assembly 6 to move, which in turn raises the right chair leg assembly 2, while the left chair leg assembly 2 falls back down. This cycle repeats, resulting in alternating, asynchronous raising and lowering movements of the two chair leg assemblies 2.

[0082] When the user needs to stop, the drive motor 3 is de-energized, and the self-locking characteristic of the worm gear reducer locks the entire transmission chain, keeping the chair leg assembly 2 stably at the current angle, ensuring safety and reliability.

[0083] In summary, the asynchronous lifting and lowering drive structure for massage chair legs provided in this embodiment of the invention, through the ingenious integration of multiple technical features such as single motor drive, bevel gear splitting, 180° phase difference of incomplete gears, and annular double rack slider, reliably realizes the asynchronous lifting and lowering function of chair legs with extremely low cost and compact structure, greatly improving the human-computer interaction experience and user comfort of the massage chair.

[0084] 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. An asynchronous lifting and lowering drive structure for the legs of a massage chair, characterized in that, Includes a base frame and chair leg assemblies, drive motors, bevel gear transmission mechanisms, incomplete gear assemblies, rack-and-pinion slider assemblies, and linkage mechanisms, all mounted on the base frame. The output shaft of the drive motor is connected to the input end of the bevel gear transmission mechanism. The bevel gear transmission mechanism includes two output ends that rotate in opposite directions, and the two output ends that rotate in opposite directions mesh with the two incomplete gear assemblies respectively. The tooth distribution angle of the incomplete gear assembly is less than 360°, and the tooth distribution phase difference between the two incomplete gear assemblies is 180°. Each of the incomplete gear assemblies engages with a rack-and-pinion slider assembly, which is slidably disposed within a groove in the base frame; the slider assembly is hinged to the chair leg assembly via a linkage mechanism. The drive motor drives the two chair leg assemblies to achieve asynchronous lifting and lowering movements through a transmission chain consisting of a bevel gear transmission mechanism, an incomplete gear assembly, a slider assembly, and a linkage mechanism.

2. The massage chair leg asynchronous lifting and falling driving structure according to claim 1, characterized in that: The bevel gear transmission mechanism includes two driven gears and two bevel gear assemblies. The two driven gears are distributed on both sides of the output shaft of the drive motor and are respectively connected to the output shaft of the drive motor. Each driven gear is connected to an incomplete gear assembly through a bevel gear assembly.

3. The massage chair leg asynchronous lifting and falling driving structure according to claim 2, characterized in that: The bevel gear assembly includes a first bevel gear and a second bevel gear that mesh with each other. The driven gear meshes with the first bevel gear, and the incomplete gear assembly is fixedly mounted on the output shaft of the second bevel gear.

4. The massage chair leg asynchronous lifting and falling driving structure according to claim 3, characterized in that: The rack-and-tooth slider assembly includes a ring-shaped slider body and two racks disposed on the slider body. The slider body includes two straight segments and two arc segments. The two straight segments are arranged in parallel vertically. The two arc segments are respectively connected to the same side ends of the two straight segments. The two racks are respectively disposed on the opposite surfaces of the two straight segments. The incomplete gear assembly meshes with the racks on the slider body. The two straight segments are provided with strip-shaped protrusions on their opposing surfaces. The base frame has a strip-shaped slide groove. The strip-shaped protrusions cooperate with the strip-shaped slide groove. When the incomplete gear assembly is driven, it drives the slider body to reciprocate linearly along the strip-shaped slide groove of the base frame.

5. The massage chair leg asynchronous lifting and falling driving structure according to claim 4, characterized in that: The linkage mechanism includes a first link and a second link. One end of the first link is hinged to the slider body, 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 base frame, and the other end of the second link is hinged to the bottom of the chair leg assembly.

6. The massage chair leg asynchronous lifting and falling driving structure according to claim 3, characterized in that: It also includes a limiting component, which includes a limiting body and two connecting arms extending outward from opposite ends of the limiting body. The limiting body and the two connecting arms together form a receiving space that can accommodate the incomplete gear assembly. The limiting body is provided with a through hole for the output shaft of the second bevel gear to pass through. The incomplete gear assembly and the second bevel gear are respectively disposed on both sides of the limiting body. The two connecting arms are respectively fixedly connected to the base frame.

7. The asynchronous lifting and lowering drive structure for the massage chair legs according to claim 3, characterized in that: The effective meshing angle of the gear teeth in the incomplete gear assembly is 120°-180°, and the gear tooth module matches the module of the rack on the slider assembly.

8. The asynchronous lifting and lowering drive structure for the massage chair legs according to claim 1, characterized in that: It also includes a gearbox, through which the output shaft of the drive motor is connected to the input end of the bevel gear transmission mechanism.

9. The massage chair leg asynchronous lifting and falling driving structure according to claim 8, characterized in that: The gearbox is a worm gear reducer, and the drive motor is a DC geared motor.

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