Wheelchair chassis wheel retracting and releasing mechanism for welfare seat

Abstract

The invention discloses a wheelchair chassis wheel retracting and releasing mechanism for a welfare seat, and belongs to the technical field of vehicle welfare seats. According to the wheel folding and unfolding mechanism, a traditional complex wheelchair chassis structure is optimized, when the wheels are folded and unfolded, only the lead screws on the two sides need to be driven by the motor to rotate, then the front wheel connecting rod and the rear wheel connecting rod are driven to move, and the front wheels and the rear wheels can be driven to be unfolded or folded; meanwhile, through the scientific design of the shape of the connecting rod, after the front wheel and the rear wheel move in place, the connecting rod can play a role in supporting or limiting and fixing the wheels, and the stability of the wheels during unfolding and folding is guaranteed; meanwhile, due to the design of a pull wire, after the rear wheel is unfolded, self-locking of the rear wheel supporting rod can be achieved, the stability of the unfolded wheel is guaranteed, meanwhile, when the wheel is folded, the function of assisting the rear wheel to be folded can be achieved, and in addition, due to the auxiliary function of an air spring, the action of folding and unfolding the wheel is more stable and smoother; and the stability of overall movement is guaranteed, design is scientific and reasonable, and practicability is high.

Description

Technical Field

[0001] The invention relates to the technical field of vehicle welfare seats, in particular to a wheelchair chassis retractable wheel mechanism for a welfare seat. Background Art

[0002] Welfare seats are mainly used in commercial vehicles. Their bases have the functions of rotation and lifting, so that the welfare seats can be coordinated with wheelchairs to facilitate getting on and off the vehicle for special groups such as the elderly and the disabled, avoiding the problem of manual transportation of wheelchairs.

[0003] When using a detachable welfare seat, the wheelchair lift lifts the passenger into the vehicle and fixes the wheelchair to the vehicle with a wheelchair fixing device. When using this detachable welfare seat, the wheelchair's retractable wheel function needs to be considered, that is, the wheelchair needs to be retracted after entering the vehicle and the wheels need to be unfolded after leaving the vehicle. However, the current wheelchair retractable wheel structure is complicated and cumbersome, the processing cost is high, and the failure rate is high.

[0004] To this end, we have designed a wheelchair chassis retractable wheel mechanism for welfare seats. This mechanism greatly optimizes the wheelchair chassis retractable wheel structure. By controlling the lead screw to drive the connecting rod movement, the wheel retraction and extension activities can be easily realized. At the same time, with the cooperation of the pull wire, the wheel can be locked after the wheel is released, and it can also assist in wheel retraction. Through the scientific design of the connecting rod, the connecting rod can support the wheel after the wheel is released, ensuring that the support rod is evenly stressed. There is no need to additionally assemble complex locking and supporting devices, which simplifies the chassis structure and effectively reduces the failure rate. Summary of the invention

[0005] The object of the present invention is to provide a wheelchair chassis retractable wheel mechanism for a welfare seat to solve the problems raised in the above-mentioned background technology.

[0006] To achieve the above object, the present invention provides the following technical solutions: A wheelchair chassis retractable wheel mechanism for a welfare seat comprises a chassis frame, a front wheel and a rear wheel, wherein the front wheel and the rear wheel are respectively provided with a front wheel support rod and a rear wheel support rod, and the front wheel support rod and the rear wheel support rod are respectively connected to the chassis frame through a front wheel support shaft and a rear wheel support shaft, and further comprises A front wheel connecting rod, one end of which is rotatably connected to the front wheel supporting rod, and is used to drive the front wheel supporting rod to rotate; A rear wheel connecting rod, one end of which is rotatably connected to the rear wheel supporting rod, and is used to drive the rear wheel supporting rod to rotate; The connecting rod driving mechanism is used to drive the front wheel connecting rod and the rear wheel connecting rod to move synchronously, so as to realize the simultaneous folding or unfolding of the front wheel and the rear wheel; The cable locking mechanism is used to limit and fix the rear wheel support rod on the chassis frame after the rear wheel is unfolded; The front wheel connecting rod and the rear wheel connecting rod are provided with support limit parts for preventing the front wheel supporting rod and the rear wheel supporting rod from automatically retracting after being deployed, so as to provide support force for the deployed front wheels and rear wheels.

[0007] As a further preferred embodiment of the present invention: the connecting rod driving mechanism includes a lead screw rotatably arranged on both sides of the chassis frame, a slider threadably arranged on the chassis frame is provided, an L-shaped plate is rotatably connected to the outer side of the slider, the front side of the L-shaped plate is rotatably connected to the front wheel connecting rod, the lower end of the L-shaped plate is fixedly connected to the rear wheel connecting rod, and a motor for driving the lead screw to rotate is provided on the chassis frame.

[0008] As a further preferred embodiment of the present invention, the rear wheel support shaft comprises an inner fixed shaft fixedly connected to the chassis frame, an outer rotating tube is rotatably sleeved on the outer side of the inner fixed shaft, and the rear wheel support rod is fixedly connected to the outer rotating tube.

[0009] As a further preferred embodiment of the present invention: the wire locking mechanism includes a fixed sleeve fixed on the rear wheel support rod, one end of the fixed sleeve is connected to the outer rotating tube, a sliding head is slidably arranged in the fixed sleeve, one end of the sliding head passes through the fixed sleeve and the outer rotating tube, and is inserted in the inner fixed shaft, a spring is arranged between the other end of the sliding head and the fixed sleeve, a wire is connected to the side of the sliding head away from the inner fixed shaft, the wire passes through the fixed sleeve and is connected to the wire adjustment rod, and the wire adjustment rod is movably arranged on the chassis frame for pulling the wire.

[0010] As a further preferred embodiment of the present invention: the support limiting portion includes a front wheel support shaft contact portion and a rear wheel support shaft contact portion, the front wheel support shaft contact portion is located at the front side of the middle portion of the front wheel connecting rod, and is used to abut against the front wheel support shaft, and the rear wheel support shaft contact portion is located at the rear side of the rear wheel connecting rod, and is used to abut against the rear wheel support shaft.

[0011] As a further preferred embodiment of the present invention: a rear wheel support shaft snap-in corresponding to the rear wheel support shaft is provided at the lower end of the rear wheel connecting rod, and when the rear wheel support rod is retracted, the rear wheel support shaft snap-in can be snapped onto the rear wheel support shaft.

[0012] As a further preferred embodiment of the present invention: the wire adjustment rod is rotatably arranged in the middle of the chassis frame, a wire connecting plate is arranged at one end of the wire adjustment rod, a wire guide tube for guiding the wire is arranged on the chassis frame, and one end of the wire passes through the wire guide tube and is connected to the wire connecting plate.

[0013] As a further preferred embodiment of the present invention: a limiting snap-in is provided on the front side of the rear wheel connecting rod, and a rear wheel connecting rod limiting plate corresponding to the limiting snap-in is provided on the side wall of the chassis frame. When the rear wheel support rod is unfolded, the limiting snap-in is clamped on the rear wheel connecting rod limiting plate.

[0014] As a further preferred solution of the present invention: a gas spring is hinged on the front side of the side wall of the chassis frame, and an output end of the gas spring is hinged to the rear wheel connecting rod.

[0015] Compared with the prior art, the present invention has the following beneficial effects: The wheel retracting and extending mechanism of the wheelchair chassis for the welfare seat optimizes the traditional complex wheelchair chassis structure. When retracting and extending the wheels, it is only necessary to drive the lead screws on both sides to rotate through the motor, thereby driving the front and rear wheel connecting rods to move, and the front and rear wheels can be driven to unfold or retract; at the same time, through the scientific design of the connecting rod shape, after the front and rear wheels move into place, the connecting rod can play a supporting or limiting role in fixing the wheels, ensuring the stability of the wheels when unfolding and retracting; at the same time, the design of the pull wire enables the rear wheel support rod to be self-locked after the rear wheel is unfolded, ensuring the stability of the wheel after unfolding, and at the same time, it can also assist in the folding of the rear wheel when the wheel is retracted. Coupled with the auxiliary role of the gas spring, the movement of the wheel when folding and unfolding is smoother, ensuring the stability of the overall movement. The design is scientific and reasonable, and the practicability is strong. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 The three-dimensional structure of the wheelchair chassis retractable wheel mechanism for the welfare seat of the present invention when the wheels are unfolded Figure 1 ; Figure 2 for Figure 1 A magnified schematic diagram of the structure at the middle L-shaped plate; Figure 3 The three-dimensional structure of the wheelchair chassis retractable wheel mechanism for the welfare seat of the present invention when the wheels are unfolded Figure 2 ; Figure 4 for Figure 3 An enlarged schematic diagram of the structure at the middle pull wire adjustment rod; Figure 5 for Figure 3 An enlarged schematic diagram of the structure at the middle and rear wheel connecting rod limit plate; Figure 6 The three-dimensional structure of the wheelchair chassis retractable wheel mechanism for the welfare seat of the present invention when the wheels are unfolded Figure 3 ; Figure 7 It is a side view structural schematic diagram of the wheelchair chassis retractable wheel mechanism for the welfare seat of the present invention when the wheels are unfolded; Figure 8 It is a cross-sectional structural diagram of the fixing sleeve of the retractable wheel mechanism of the wheelchair chassis for the welfare seat of the present invention; Fig. 9 for Figure 8 An enlarged schematic diagram of the structure of the middle fixed sleeve; Fig.10The three-dimensional structure of the wheelchair chassis retractable wheel mechanism for the welfare seat of the present invention when the wheels are retracted Figure 1 ; Fig.11 The three-dimensional structure of the wheelchair chassis retractable wheel mechanism for the welfare seat of the present invention when the wheels are unfolded Figure 2 ; Fig.12 for Fig.11 An enlarged schematic diagram of the structure at the center rear wheel support shaft snap-on.

[0017] In the figure: 1. chassis frame; 2. cable adjustment rod; 3. front wheel; 4. rear wheel; 5. front wheel support rod; 6. front wheel support shaft; 7. cable lock; 8. cable; 9. rear wheel support rod; 10. rear wheel support shaft; 11. rear wheel connecting rod; 12. rear wheel support shaft snap-on; 13. front wheel connecting rod; 14. front wheel support shaft contact part; 15. screw; 16. slider; 17. motor; 18. drive shaft; 19. gear steering box; 20. gas spring; 21. cable connecting plate; 22. cable guide tube; 23. rear wheel support shaft contact part; 24. sliding head; 25. fixing groove; 26. spring; 27. fixing sleeve; 28. rear wheel connecting rod limit plate; 29. ​​limit snap-on; 30. inner fixed shaft; 31. outer rotating tube; 32. L-shaped plate. DETAILED DESCRIPTION

[0018] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention. Example 1

[0019] See also Figure 1-12 The present embodiment provides a wheelchair chassis retractable wheel mechanism for a welfare seat, including a chassis frame 1, a front wheel 3 and a rear wheel 4, on which a front wheel support rod 5 and a rear wheel support rod 9 are respectively provided, and the front wheel 3 and the rear wheel 4 are rotationally connected to the front wheel support rod 5 and the rear wheel support rod 9, which is a conventional design and will not be described in detail; and the front wheel support rod 5 and the rear wheel support rod 9 are rotationally connected to the chassis frame 1 through the front wheel support shaft 6 and the rear wheel support shaft 10, respectively. In actual application, the retraction and deployment of the front wheel 3 and the rear wheel 4 are realized by the rotation of the front wheel support rod 5 and the rear wheel support rod 9 on the chassis frame 1. The above structure is a conventional design familiar to those skilled in the art and will not be described in detail.

[0020] In the present application, in order to realize the movement of the front wheel support rod 5 and the rear wheel support rod 9 on the chassis frame 1, it is realized by designing a reciprocating front wheel connecting rod 13 and a rear wheel connecting rod 11. Specifically, the front wheel connecting rod 13 and the rear wheel connecting rod 11 are arranged on both sides of the chassis frame 1 corresponding to the front and rear wheels. One end of the front wheel connecting rod 13 is rotatably connected to the front wheel support rod 5, and is used to drive the front wheel support rod 5 to rotate, and one end of the rear wheel connecting rod 11 is rotatably connected to the rear wheel support rod 9, and is used to drive the rear wheel support rod 9 to rotate.

[0021] In order to realize the movement of the front wheel link 13 and the rear wheel link 11, a link driving mechanism is provided on the chassis frame 1, which is used to drive the front wheel link 13 and the rear wheel link 11 to move synchronously, thereby realizing the simultaneous folding or unfolding of the front wheel 3 and the rear wheel 4; Figure 1 , Figure 2 as well as Figure 6 As shown, it includes a lead screw 15 rotatably arranged on both sides of the chassis frame 1, a slider 16 threadedly connected to the lead screw 15 is slidably arranged on the chassis frame 1, an L-shaped plate 32 is rotatably connected to the outer side of the slider 16, the front side of the L-shaped plate 32 is rotatably connected to the front wheel connecting rod 13, the lower end of the L-shaped plate 32 is fixedly connected to the rear wheel connecting rod 11, and a motor 17 for driving the lead screw 15 to rotate is arranged on the chassis frame 1. It should be noted that the drive of the lead screw 15 should be a conventional design familiar to those skilled in the art. Preferably, in this application, the motor 17 is arranged on the front side of the chassis frame 1. In order to be able to drive the retraction and deployment of the wheels on both sides at the same time, a dual-axis motor is preferably used, and the output ends of both sides are connected to the drive shaft 18. The transmission of the drive shaft 18 and the lead screw 15 can be realized by a gear steering box 19 on the chassis frame 1. Among them, the gear steering box 19 is a conventional general structure in the field, which can be obtained by customization and will not be repeated; those skilled in the art can also realize the rotation of the lead screw 15 through other conventional designs, and this application will not repeat the limitation.

[0022] In order to ensure the stability of the front and rear wheels after they are deployed, the mechanism is also provided with a cable locking mechanism. At the same time, support limit parts are provided on the front wheel connecting rod 13 and the rear wheel connecting rod 11.

[0023] The wire locking mechanism is used to realize the position fixing of the rear wheel support rod 9 on the chassis frame 1 after the rear wheel 4 is unfolded; specifically, Figure 1 , Figure 3 , Figure 4 , Figure 8 as well as Fig. 9As shown, the rear wheel support shaft 10 includes an inner fixed shaft 30 fixedly connected to the chassis frame 1, the outer rotating sleeve of the inner fixed shaft 30 is rotatably sleeved with an outer rotating tube 31, and the rear wheel support rod 9 is fixedly connected to the outer rotating tube 31; the cable locking mechanism includes a fixed sleeve 27 fixed on the rear wheel support rod 9, one end of the fixed sleeve 27 is connected to the outer rotating tube 31, a sliding head 24 is slidably arranged in the fixed sleeve 27, one end of the sliding head 24 passes through the fixed sleeve 27 and the outer rotating tube 31, and is inserted into the inner fixed shaft 30, that is, a slot corresponding to the sliding head 24 is arranged on the inner fixed shaft 30, a spring 26 is arranged between the other end of the sliding head 24 and the fixed sleeve 27, a cable 8 is connected to the side of the sliding head 24 away from the inner fixed shaft 30, the cable 8 passes through the fixed sleeve 27 and is connected to the cable adjustment rod 2, and the cable adjustment rod 2 is movably arranged on the chassis frame 1 for pulling the cable 8; specifically, refer to Figure 3 as well as Figure 4 The wire adjustment rod 2 is rotatably arranged in the middle of the chassis frame 1. A wire connection plate 21 is arranged at one end of the wire adjustment rod 2. A wire guide 22 for guiding the wire 8 is arranged on the chassis frame 1. One end of the wire 8 passes through the wire guide 8 and is connected to the wire connection plate 21. When the wire adjustment rod 2 moves downward, the wire 8 should be in a relaxed state. Figure 8 As shown, the spring 26 should exert force to push the sliding head 24 into the inner fixed shaft 30, so that the outer rotating tube 31 is stuck, thereby fixing the rear wheel 4 after it is unfolded; on the contrary, when the driving cable adjustment rod 2 moves upward, the cable 8 is tightened, driving the sliding head 24 to leave the inner fixed shaft 30, and the spring 26 is compressed. At this time, the limiting fixation of the outer rotating tube 31 is released, and the screw 15 can be driven to rotate, thereby causing the front wheel connecting rod 13 and the rear wheel connecting rod 11 to drive the two support rods to rotate, thereby realizing wheel retraction.

[0024] The support limiter is used to prevent the front wheel support rod 5 and the rear wheel support rod 9 from automatically retracting after being deployed, and to provide support force for the deployed front wheel 3 and the rear wheel 4. Figure 1 , Figure 3 as well as Figure 6 As shown, the support limiting portion includes a front wheel support shaft contact portion 14 and a rear wheel support shaft contact portion 23. The front wheel support shaft contact portion 14 is located at the front middle portion of the front wheel connecting rod 13. When the front wheel 3 is unfolded, it abuts against the front wheel support shaft 6. The rear wheel support shaft contact portion 23 is located at the rear side of the rear wheel connecting rod 11. When the rear wheel 4 is unfolded, it abuts against the rear wheel support shaft 10.

[0025] Considering the stability after the wheels are retracted, Figure 1 , Fig.11 as well as Fig.12 As shown, a rear wheel support shaft snap-in 12 corresponding to the rear wheel support shaft 10 is provided at the lower end of the rear wheel connecting rod 11 , and when the rear wheel support rod 9 is retracted, the rear wheel support shaft snap-in 12 can be snapped onto the rear wheel support shaft 10 .

[0026] At the same time, in order to further ensure the stability of the wheels after they are unfolded, Figure 5-7 As shown, a limiting slot 29 is provided on the front side of the rear wheel connecting rod 11, and a rear wheel connecting rod limiting plate 28 corresponding to the limiting slot 29 is provided on the side wall of the chassis frame 1. When the rear wheel support rod 9 is unfolded, the limiting slot 29 is clamped on the rear wheel connecting rod limiting plate 28; at this time, the rear wheel support shaft contact portion 23 on the rear side of the rear wheel connecting rod 11 abuts against the rear wheel support shaft 10, and the rear wheel connecting rod 11 realizes front and rear positioning, while the front wheel support shaft contact portion 14 on the front side of the front wheel connecting rod 13 abuts against the front wheel support shaft 6, and the front wheel connecting rod 13 and the rear wheel connecting rod 11 are connected by an L-shaped plate 32. Therefore, the stability of the front wheel connecting rod 13 and the rear wheel connecting rod 11 after the wheels are unfolded is fully guaranteed, and the stability of the wheels after unfolding is guaranteed.

[0027] At the same time, in order to make the connecting rod smoother and more stable during movement and save more effort when retracting the wheel, Figure 1 As shown, a gas spring 20 is hinged on the front side of the side wall of the chassis frame 1, and the output end of the gas spring 20 is hinged to the rear wheel connecting rod 11. The gas spring 20 is an existing conventional structure and can be obtained by purchase, so it will not be described in detail in this application.

[0028] In order to enable those skilled in the art to better understand the present application, the working principle of the retractable wheel mechanism will be described below: Wheel release status: Figure 1 , Figure 5 , Figure 6 , Figure 7 as well as Fig. 9 As shown, the motor 17 drives the lead screw 15 to rotate, and after the slider 16 moves into place, the gas spring 20 also returns to the initial contracted state. At this time, the front wheel connecting rod 13 pushes the front wheel support rod 5 to open, and the front wheel support shaft contact portion 14 on the front wheel connecting rod 13 abuts against the front wheel support shaft 6; at the same time, the rear wheel connecting rod 11 drives the rear wheel support rod 9 to open backward by moving forward, so that the rear wheel 4 is opened. At this time, the rear wheel support shaft contact portion 23 at the tail of the rear wheel connecting rod 11 abuts against the rear wheel support shaft 10, and the front side limiting bayonet 29 is clamped on the rear wheel connecting rod limiting plate 28. At the same time, the cable adjustment rod 2 and the cable connecting plate 21 are in the lower position, and the cable 8 is in a relatively relaxed state. At this time, under the action of the spring 26, the sliding head 24 is inserted into the internal fixed shaft 30, so that the rear wheel support rod 9 no longer rotates, that is, the front and rear wheels are in the open state; Retracting status: Figure 10-12As shown, when the wheel is retracted on the basis of the wheel releasing state, the motor 17 drives the lead screw 15 to move, so that the slider 16 slides to the rear side. At this time, the wire adjustment rod 2 moves upward under the action of external force, so that the wire connecting plate 21 tightens the wire 8, and then the wire 8 pulls the sliding head 24 to compress the spring 26, and makes the sliding head 24 leave the inner fixed shaft 30, contact the limit of the rear wheel support rod 9, and at the same time, the rear wheel support rod 9 is counterclockwise (the direction is Figure 1 The rotational force of the rear wheel connecting rod 13 (with the middle position as a reference) cooperates with the rear wheel connecting rod 13 to move backward, so that the rear wheel supporting rod 9 rotates in the opposite direction, that is, retracts. At the same time, the front wheel connecting rod 13 pulls the front wheel supporting rod 5 inward to achieve the folding of the front and rear wheels. After folding, the rear wheel supporting shaft bayonet 12 on the rear wheel connecting rod 9 is just stuck on the rear wheel supporting shaft 10, so that the limiting fixation of the connecting rod after folding is achieved.

[0029] It should be noted that in actual applications, in order to achieve folding and folding, gaps should be provided between the connecting rod, gas spring 20 and other accessories, and the position design of the rotation point between the connecting rod and the support rod are all conventional designs familiar to those skilled in the art, and this application will not elaborate on the limitations. At the same time, the up and down adjustment of the wire adjustment rod 2 should be achieved by a cylinder or other conventional external telescopic structure, which is also a conventional design familiar to those skilled in the art, and its driving structure can be selected according to the needs, and this application will not elaborate on the limitations.

[0030] It should be noted that in Figure 1 , Figure 3 , Figure 6 as well as Figure 7 In order to enable those skilled in the art to better understand the structure of the pull wire 8, the state of the pull wire 8 after being pulled out from the pull wire conduit 22 is also shown. In actual application, the state of the pull wire 8 is as follows Figure 4 As shown, one end of the pull wire 8 is connected to the pull wire connecting plate 21, and the other end is connected to the sliding head 24 after being guided by the pull wire conduit 22. The connection of the pull wire 8 is realized through the fixing groove 25 in the sliding head 24. The connection method is a conventional design familiar to those skilled in the art and will not be repeated. The direction of the pull wire 8 is realized by the pull wire conduit 22, and its arrangement method is also a conventional design familiar to those skilled in the art and will not be repeated.

[0031] It should be noted that the above embodiments are only specific and clear descriptions of the technical solutions and technical features of the present application. For those skilled in the art, solutions or features that belong to the prior art or common knowledge are not described in detail in the above embodiments.

[0032] In addition, the technical solutions of the present application are not limited to the above-mentioned embodiments. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation methods that can be understood by those skilled in the art.

Claims

1. A wheelchair chassis retractable wheel mechanism for a welfare seat, comprising a chassis frame (1), a front wheel (3) and a rear wheel (4), wherein the front wheel (3) and the rear wheel (4) are respectively provided with a front wheel support rod (5) and a rear wheel support rod (9), wherein the front wheel support rod (5) and the rear wheel support rod (9) are respectively connected to the chassis frame (1) via a front wheel support shaft (6) and a rear wheel support shaft (10), and characterized in that: Also includes A front wheel connecting rod (13), one end of which is rotatably connected to the front wheel supporting rod (5) and is used to drive the front wheel supporting rod (5) to rotate; A rear wheel connecting rod (11), one end of which is rotatably connected to the rear wheel supporting rod (9) and is used to drive the rear wheel supporting rod (9) to rotate; A connecting rod driving mechanism, used for driving the front wheel connecting rod (13) and the rear wheel connecting rod (11) to move synchronously, thereby achieving simultaneous folding or unfolding of the front wheel (3) and the rear wheel (4); A pull-wire locking mechanism, used to achieve position-limited fixation of the rear wheel support rod (9) on the chassis frame (1) after the rear wheel (4) is deployed; The front wheel connecting rod (13) and the rear wheel connecting rod (11) are provided with support limit parts for preventing the front wheel supporting rod (5) and the rear wheel supporting rod (9) from automatically retracting after being deployed, and providing support force for the deployed front wheel (3) and the rear wheel (4).

2. The wheelchair chassis retractable wheel mechanism for a welfare seat according to claim 1, characterized in that: The connecting rod driving mechanism comprises a lead screw (15) rotatably arranged on both sides of the chassis frame (1); a slider (16) threadedly connected to the lead screw (15) is slidably arranged on the chassis frame (1); an L-shaped plate (32) is rotatably connected to the outer side of the slider (16); the front side of the L-shaped plate (32) is rotatably connected to the front wheel connecting rod (13); the lower end of the L-shaped plate (32) is fixedly connected to the rear wheel connecting rod (11); and a motor (17) for driving the lead screw (15) to rotate is arranged on the chassis frame (1).

3. The wheelchair chassis retractable wheel mechanism for a welfare seat according to claim 1, characterized in that: The rear wheel support shaft (10) comprises an inner fixed shaft (30) fixedly connected to the chassis frame (1); an outer rotating tube (31) is rotatably sleeved on the outside of the inner fixed shaft (30); and the rear wheel support rod (9) is fixedly connected to the outer rotating tube (31).

4. The wheelchair chassis retractable wheel mechanism for a welfare seat according to claim 3, characterized in that: The cable locking mechanism comprises a fixing sleeve (27) fixed on the rear wheel support rod (9), one end of the fixing sleeve (27) is connected to the outer rotating tube (31), a sliding head (24) is slidably arranged in the fixing sleeve (27), one end of the sliding head (24) passes through the fixing sleeve (27) and the outer rotating tube (31), and is inserted into the inner fixed shaft (30), a spring (26) is arranged between the other end of the sliding head (24) and the fixing sleeve (27), a cable (8) is connected to the side of the sliding head (24) away from the inner fixed shaft (30), the cable (8) passes through the fixing sleeve (27) and is connected to the cable adjustment rod (2), and the cable adjustment rod (2) is movably arranged on the chassis frame (1) for pulling the cable (8).

5. The wheelchair chassis retractable wheel mechanism for a welfare seat according to claim 1, characterized in that: The support limiting portion comprises a front wheel support shaft contact portion (14) and a rear wheel support shaft contact portion (23); the front wheel support shaft contact portion (14) is located at the front side of the middle of the front wheel connecting rod (13) and is used to abut against the front wheel support shaft (6); and the rear wheel support shaft contact portion (23) is located at the rear side of the rear wheel connecting rod (11) and is used to abut against the rear wheel support shaft (10).

6. The wheelchair chassis retractable wheel mechanism for a welfare seat according to claim 2, characterized in that: A rear wheel support shaft snap-in (12) corresponding to the rear wheel support shaft (10) is provided at the lower end of the rear wheel connecting rod (11); when the rear wheel support rod (9) is retracted, the rear wheel support shaft snap-in (12) can be snapped onto the rear wheel support shaft (10).

7. The wheelchair chassis retractable wheel mechanism for a welfare seat according to claim 4, characterized in that: The wire adjustment rod (2) is rotatably arranged in the middle of the chassis frame (1); a wire connection plate (21) is arranged at one end of the wire adjustment rod (2); a wire guide tube (22) for guiding the wire (8) is arranged on the chassis frame (1); one end of the wire (8) passes through the wire guide tube (8) and is connected to the wire connection plate (21).

8. The wheelchair chassis retractable wheel mechanism for a welfare seat according to claim 5, characterized in that: A limit snap-in opening (29) is provided on the front side of the rear wheel connecting rod (11), and a rear wheel connecting rod limit plate (28) corresponding to the limit snap-in opening (29) is provided on the side wall of the chassis frame (1); when the rear wheel support rod (9) is unfolded, the limit snap-in opening (29) is clamped on the rear wheel connecting rod limit plate (28).

9. The wheelchair chassis retractable wheel mechanism for a welfare seat according to claim 2, characterized in that: A gas spring (20) is hingedly connected to the front side of the side wall of the chassis frame (1), and an output end of the gas spring (20) is hingedly connected to the rear wheel connecting rod (11).

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