Chassis assembly and seat

Abstract

The utility model discloses a chassis assembly and a seat. The chassis assembly comprises a base, a cushion, a seat depth adjusting module, an angle adjusting module, a backrest and a third driving mechanism. The cushion comprises a first shell and a second shell which are connected with each other, and the first shell is rotationally connected with the base. The first shell and the second shell are connected through a seat depth adjusting module, and the seat depth adjusting module comprises a first driving mechanism. The angle adjusting module comprises a second driving mechanism. The backrest is rotationally connected to the base, and the third driving mechanism is used for driving the backrest to rotate relative to the base. The seat cushion is divided into the first shell part and the second shell part, the seat depth adjusting module is arranged to drive the second shell part to rotate to achieve seat depth adjustment, the angle adjusting module is arranged to drive the whole seat cushion to rotate relative to the base to achieve angle adjustment, adjustment of the two modules and the backrest is driven by the driving mechanism, manual adjustment is not needed, and more convenience is achieved.

Description

Technical Field

[0001] This utility model relates to the field of seating technology, specifically to a chassis assembly and a seat. Background Technology

[0002] Chairs are now a common piece of equipment used daily, and the chair base is an essential component. To improve user comfort, seat depth is a crucial parameter. Seat depth refers to the distance from the outermost edge of the seat cushion to the backrest. If the seat depth is too long, the knees cannot properly rest on the edge of the seat cushion when bent; if the seat depth is too short, the thighs are squeezed against the edge of the seat cushion, causing strain. Current technology incorporates structures on the chassis to adjust the seat cushion or backrest tilt angle, or to adjust the seat depth, allowing different users to adjust the angle and seat depth for a comfortable experience. However, the existing methods for adjusting the chassis are relatively cumbersome. Utility Model Content

[0003] This invention aims to solve at least one of the technical problems existing in the prior art. To this end, this invention proposes a chassis assembly that allows for more convenient adjustment of the seat depth and the tilt angle of the seat cushion and backrest.

[0004] This utility model also proposes a seat having the above-mentioned chassis components.

[0005] A chassis assembly according to a first aspect of the present invention includes a base, a seat cushion, a seat depth adjustment module, an angle adjustment module, a backrest, and a third drive mechanism. The seat cushion is mounted above the base and includes a first shell and a second shell connected to each other. The first shell is rotatably connected to the base. The first shell and the second shell are connected via the seat depth adjustment module, which includes a first drive mechanism for driving the second shell to move back and forth relative to the first shell. The angle adjustment module is mounted between the base and the seat cushion and includes a second drive mechanism for driving the seat cushion to rotate relative to the base. The backrest is rotatably connected to the base, and the chassis assembly further includes a third drive mechanism for driving the backrest to rotate relative to the base.

[0006] The chassis assembly according to the present invention has at least the following advantages: In the prior art, the adjustment of the seat cushion and backrest tilt angle often uses a mechanical angle adjuster, while the adjustment of the seat depth also uses mechanical structures such as limit bolts and limit grooves. Adjustment requires manually turning the angle adjuster or limit bolt, then adjusting the chassis to the appropriate position before resetting the angle adjuster and limit bolt, which is cumbersome. The chassis assembly of the present invention divides the seat cushion into a first shell and a second shell. A seat depth adjustment module drives the second shell to rotate to achieve seat depth adjustment, and an angle adjustment module drives the entire seat cushion to rotate relative to the base to achieve angle adjustment. Both modules and the backrest adjustment are driven by a drive mechanism, eliminating the need for manual adjustment and making it more convenient.

[0007] According to some embodiments of the present invention, the first shell has a placement cavity, and the second shell is movably installed in the placement cavity. The first shell includes a first side plate, and the second shell includes a second side plate and a top plate that are connected to each other. The first side plate and the second side plate are spaced apart in the front-back direction to form an active space, and the top plate covers the active space.

[0008] According to some embodiments of this utility model, the seat depth adjustment module further includes a worm, a worm wheel, a gear, and a rack. The first drive mechanism is installed on the second housing, and the output end of the first drive mechanism is connected to the worm. The worm wheel meshes with the worm, the gear is coaxially connected to the worm wheel and connected to the second housing, the gear meshes with the rack, and the rack is disposed in the placement cavity along the front-back direction of the first housing and fixedly connected to the first housing. The first drive mechanism drives the worm to rotate, so that the worm wheel and the gear rotate coaxially, thereby moving the gear and causing the second housing to move back and forth relative to the first housing.

[0009] According to some embodiments of the present invention, the rack is disposed at the rear end of the placement cavity, the chassis assembly further includes a plurality of rollers, the plurality of rollers are spaced apart at the front end of the placement cavity in the front-rear direction, and the second shell is slidably placed on the rollers.

[0010] According to some embodiments of the present invention, the angle adjustment module further includes a push rod and a crank. The second drive mechanism is connected to the push rod. The two ends of the crank are respectively connected to the push rod and the first housing. The end of the crank connected to the first housing is higher than the end of the crank connected to the push rod. The second drive mechanism is used to drive the push rod to move back and forth so that the crank drives the first housing to rotate relative to the base.

[0011] According to some embodiments of the present invention, the base includes a third housing and a fourth housing. The third housing is slidably connected to the fourth housing, and the fourth housing is rotatably connected to the first housing. The push rod is fixedly connected to the third housing, and the crank is rotatably connected to the third housing. The second driving mechanism drives the push rod to move back and forth to cause the third housing to slide relative to the fourth housing, thereby causing the crank to drive the first housing to rotate relative to the fourth housing.

[0012] According to some embodiments of the present invention, the third housing has a limiting groove, one end of the crank is rotatably connected in the limiting groove, and from back to front, the crank gradually extends out of the limiting groove, while the other end of the crank is located outside the limiting groove and is rotatably connected to the first housing.

[0013] According to some embodiments of the present invention, two cranks are symmetrically arranged along the width direction of the base, and both cranks are connected to the third housing. The push rod pushes the third housing to slide so that the two cranks rotate.

[0014] According to some embodiments of the present invention, the chassis assembly further includes an output shaft, which passes through the base and the backrest, is rotatably connected to the base, and is fixedly connected to the backrest. The output end of the third drive mechanism is connected to the output shaft, and the third drive mechanism is used to drive the output shaft to rotate around its own axis so that the backrest rotates relative to the base.

[0015] The seat according to a second aspect embodiment of the present invention includes the chassis assembly described in any one of the first aspect embodiments.

[0016] The seat according to the present invention has at least the following advantages: In the prior art, the adjustment of the seat cushion and backrest tilt angle often uses a mechanical angle adjuster, while the seat depth adjustment also uses mechanical structures such as limit bolts and limit grooves. Adjustment requires manually turning the angle adjuster or limit bolt, then adjusting the chassis to the appropriate position before resetting the angle adjuster and limit bolt, which is cumbersome. The chassis assembly of the present invention divides the seat cushion into a first shell and a second shell. A seat depth adjustment module drives the second shell to rotate to achieve seat depth adjustment, and an angle adjustment module drives the entire seat cushion to rotate relative to the base to achieve angle adjustment. Both modules and the backrest adjustment are driven by a drive mechanism, eliminating the need for manual adjustment. The seat using this chassis assembly is more convenient in terms of user experience.

[0017] Additional aspects and advantages of this invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0018] The present invention will be further described below with reference to the accompanying drawings and embodiments, wherein:

[0019] Figure 1 This is a first perspective view of the chassis assembly in one embodiment of the present utility model;

[0020] Figure 2 This is a second perspective view of the chassis assembly in one embodiment of the present invention;

[0021] Figure 3 This is an exploded view of the seat cushion of the chassis assembly in one embodiment of the present invention.

[0022] Figure 4 This is a top view of the chassis assembly in one embodiment of the present invention;

[0023] Figure 5 for Figure 4 Sectional view of section line AA in the middle;

[0024] Figure 6 This is an exploded view of the base of the chassis assembly in one embodiment of the present invention;

[0025] Figure 7 for Figure 6 The side view of the exploded diagram shown.

[0026] Reference numerals: chassis assembly 100, base 101, seat cushion 102, seat depth adjustment module 103, backrest 104, third drive mechanism 105, angle adjustment module 106, output shaft 201, first housing 301, second housing 302, fourth housing 303, first drive mechanism 304, worm gear 305, worm wheel 306, gear 307, rack 308, roller 309, placement cavity 310, first side plate 311, second side plate 312, top plate 313, activity space 501, third housing 601, second drive mechanism 602, push rod 603, crank 604, limiting groove 605. Detailed Implementation

[0027] The embodiments of this utility model are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this utility model, and should not be construed as limiting this utility model.

[0028] In the description of this utility model, it should be understood that the directional descriptions, such as up, down, front, back, left, right, etc., indicate the directional or positional relationship based on the directional or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.

[0029] In the description of this utility model, "several" means one or more, "multiple" means two or more, "greater than," "less than," and "exceeding" are understood to exclude the stated number, while "above," "below," and "within" are understood to include the stated number. The use of "first" and "second" in the description is merely for distinguishing technical features and should not be construed as indicating or implying relative importance, or implicitly indicating the number of indicated technical features, or implicitly indicating the order of the indicated technical features.

[0030] In the description of this utility model, unless otherwise explicitly defined, terms such as "setting," "installation," and "connection" should be interpreted broadly, and those skilled in the art can reasonably determine the specific meaning of the above terms in this utility model in conjunction with the specific content of the technical solution.

[0031] In the description of this utility model, the terms "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of this utility model. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0032] refer to Figures 1 to 3According to a first aspect embodiment of the present invention, a chassis assembly 100 includes a base 101, a seat cushion 102, a seat depth adjustment module 103, an angle adjustment module 106, a backrest 104, and a third drive mechanism 105. The seat cushion 102 is mounted above the base 101 and includes a first shell 301 and a second shell 302 connected to each other. The first shell 301 is rotatably connected to the base 101. The first shell 301 and the second shell 302 are connected via the seat depth adjustment module 103, which includes a first drive mechanism 304 for driving the second shell 302 to move back and forth relative to the first shell 301. The angle adjustment module 106 is mounted between the base 101 and the seat cushion 102 and includes a second drive mechanism 602 for driving the seat cushion 102 to rotate relative to the base 101. The backrest 104 is rotatably connected to the base 101. The chassis assembly 100 also includes a third drive mechanism 105, which drives the backrest 104 to rotate relative to the base 101. In the prior art, the adjustment of the tilt angle of the seat cushion 102 and the backrest 104 often uses a mechanical angle adjuster, and the adjustment of the seat depth also uses mechanical structures such as a limit bolt and a limit groove 605. Adjustment requires manually turning the angle adjuster or the limit bolt, then adjusting the chassis to the appropriate position, and finally resetting the angle adjuster and the limit bolt, which is cumbersome. In this embodiment of the present invention, the chassis assembly 100 divides the seat cushion 102 into a first shell 301 and a second shell 302. A seat depth adjustment module 103 drives the second shell 302 to rotate to achieve seat depth adjustment, and an angle adjustment module 106 drives the entire seat cushion 102 to rotate relative to the base 101 to achieve angle adjustment. Both modules and the adjustment of the backrest 104 are driven by drive mechanisms, eliminating the need for manual adjustment and making it more convenient.

[0033] refer to Figures 3 to 5 In some embodiments of this utility model, the first shell 301 has a placement cavity 310, and the second shell 302 is movably installed within the placement cavity 310. The first shell 301 includes a first side plate 311, and the second shell 302 includes a second side plate 312 and a top plate 313 connected to each other. The first side plate 311 and the second side plate 312 are spaced apart along the front-rear direction to form an active space 501, and the top plate 313 covers the active space 501. This design allows the relatively movable first shell 301 and second shell 302 to move as they are assembled. Figure 1 As shown, this design enhances the product's aesthetics, and the top plate 313 can be used to place and install other components above the seat cushion 102. The movable space 501 provides space for the movement of the second shell 302, and the placement cavity 310 is used to place the second shell 302 and the seat depth adjustment module 103, improving space utilization. The first side plate 311 also serves to limit and abut against the second side plate 312.

[0034] refer to Figure 3 and Figure 4 In some embodiments of this utility model, the seat depth adjustment module 103 further includes a worm 305, a worm wheel 306, a gear 307, and a rack 308. A first drive mechanism 304 is mounted on the second housing 302. The output end of the first drive mechanism 304 is connected to the worm 305. The worm wheel 306 meshes with the worm 305. The gear 307 is coaxially connected to the worm wheel 306 and connected to the second housing 302. The gear 307 meshes with the rack 308. The rack 308 is arranged in the placement cavity 310 along the front-back direction of the first housing 301 and is fixedly connected to the first housing 301. The first drive mechanism 304 drives the worm 305 to rotate, so that the worm wheel 306 and the gear 307 rotate coaxially, thereby moving the gear 307 and causing the second housing 302 to move back and forth relative to the first housing 301. The first drive mechanism 304 drives the worm gear 305 to rotate, which in turn drives the worm wheel 306 to rotate, thereby causing the coaxially connected gear 307 to rotate. Since the first drive mechanism 304, worm wheel 306, and worm gear 305 are all mounted on the second housing 302, while the rack 308 is mounted on the first housing 301, the gear 307 rotates and moves along the direction of the rack 308, causing the second housing 302 to move relative to the first housing 301 in the front-back direction, thus adjusting the seat depth. The design of the worm wheel 306 and worm gear 305 allows for smoother transmission. The coaxial design of the gear 307 and worm wheel 306 effectively improves the transmission ratio, and the size of the worm wheel 306 and gear 307 can be adjusted as needed to achieve acceleration or deceleration structures. The structure is compact and stable.

[0035] It should be noted that the reference Figure 4 In some embodiments of this utility model, the first drive mechanism 304 uses a dual-head motor, and the worm gear 306, worm 305, gear 307, and rack 308 are symmetrically arranged in two sets. The two sets are respectively connected to the two output ends of the dual-head motor. In this way, the first drive mechanism 304 can drive the two transmission structures at the same time, thereby driving the second housing 302 to move, making the force on the second housing 302 more uniform and the operation more stable.

[0036] refer to Figure 3In some embodiments of this utility model, the rack 308 is disposed at the rear end of the placement cavity 310, and the chassis assembly 100 also includes a plurality of rollers 309. The plurality of rollers 309 are spaced apart in the front end of the placement cavity 310 in the front-rear direction, and the second housing 302 is slidably placed on the rollers 309. The plurality of rollers 309 can make the movement of the second housing 302 more stable. The reason for placing the rollers 309 at the front end and the rack 308 at the rear end is to make the entire seat depth adjustment assembly located at the rear end of the seat cushion 102, so that it is close to the backrest 104, making the weight distribution more concentrated, improving the overall structural stability, and the rear position makes it less likely for the user to perceive the drive mechanism during use, thus improving the user experience.

[0037] refer to Figure 1 , Figure 6 and Figure 7 In some embodiments of this utility model, the angle adjustment module 106 further includes a push rod 603 and a crank 604. A second drive mechanism 602 connects to the push rod 603. The two ends of the crank 604 are respectively connected to the push rod 603 and the first housing 301. The end of the crank 604 connected to the first housing 301 is higher than the end connected to the push rod 603. The second drive mechanism 602 drives the push rod 603 to move back and forth, so that the crank 604 drives the first housing 301 to rotate relative to the base 101. The design of the push rod 603 and crank 604 allows the rotation of the first housing 301 to be completed only by the back and forth movement of the push rod 603. Therefore, the push rod 603 can have more flexible placement options, for example... Figure 1 and Figure 6 As shown, the push rod 603 is installed inside the third housing 601 and placed inside the fourth housing 303. The forward and backward movement of the push rod 603 will not be noticeable externally, and the transmission and fixed angle states of the linkage structure are very stable. In some embodiments of this utility model, the angle adjustment module 106, such as the third drive mechanism 105 and the output shaft 201, can also be configured such that the first housing 301 is directly driven to rotate relative to the base 101 by a power element.

[0038] refer to Figure 6 and Figure 7In some embodiments of this utility model, the base 101 includes a third housing 601 and a fourth housing 303. The third housing 601 is slidably connected to the fourth housing 303, and the fourth housing 303 is rotatably connected to the first housing 301. A push rod 603 is fixedly connected to the third housing 601, and a crank 604 is rotatably connected to the third housing 601. A second drive mechanism 602 drives the push rod 603 to move back and forth, thereby causing the third housing 601 to slide relative to the fourth housing 303, which in turn causes the crank 604 to rotate relative to the fourth housing 303. Dividing the base 101 into the relatively slidably connected third housing 601 and fourth housing 303 allows for more flexible positioning of the crank 604 and push rod 603. Furthermore, the relative sliding between the housings allows the force of the push rod 603 to be better transmitted to the crank 604, thereby causing the crank 604 to rotate and thus rotating the first housing 301. The specific principle is that the third housing 601, the crank 604 and the first housing 301 are rotatably connected to form a linkage transmission structure, and the push rod 603 applies a thrust to the third housing 601 to realize the transmission.

[0039] It should be noted that the reference Figure 6 In some embodiments of this utility model, an angle groove is provided at the connection position between the first housing 301 and the crank 604. The opening of the angle groove is greater than the end angle of the crank 604. This design allows the end of the crank 604 connected to the first housing 301 to rotate better.

[0040] refer to Figure 6 and Figure 7 In some embodiments of this utility model, the third housing 601 has a limiting groove 605. One end of the crank 604 is rotatably connected to the limiting groove 605. From back to front, the crank 604 gradually extends out of the limiting groove 605. The other end of the crank 604 is located outside the limiting groove 605 and is rotatably connected to the first housing 301. The limiting groove 605 can prevent the crank 604 from swinging left and right after being subjected to force, allowing it to rotate better around its two endpoints. The crank 604 is configured as follows... Figure 7 The shape shown allows the crank 604 to easily rotate upwards after being subjected to a forward thrust, thereby driving the first housing 301 to rotate. It should be noted that... Figure 7 The dotted lines shown represent the portion of the crank 604 obscured by the first housing 301 and the third housing 601, representing perspective treatment to fully display the shape of the crank 604.

[0041] refer to Figure 6In some embodiments of this utility model, two cranks 604 are symmetrically arranged along the width direction of the base 101. Both cranks 604 are connected to the third housing 601. The push rod 603 pushes the third housing 601 to slide, so that the two cranks 604 rotate. In this way, the second drive mechanism 602 can simultaneously drive the two cranks 604 to rotate through the third housing 601 and the push rod 603, thereby driving the first housing 301 to rotate, making the force on the first housing 301 more uniform and the operation smoother.

[0042] refer to Figure 1 and Figure 2 In some embodiments of this utility model, the chassis assembly 100 further includes an output shaft 201, which passes through the base 101 and the backrest 104. The output shaft 201 is rotatably connected to the base 101, and the backrest 104 is fixedly connected to the output shaft 201. The output end of the third drive mechanism 105 is connected to the output shaft 201. The third drive mechanism 105 is used to drive the output shaft 201 to rotate around its own axis, so that the backrest 104 rotates relative to the base 101. This design is simple and efficient, allowing the third drive mechanism 105 to effectively drive the backrest 104 to rotate, without requiring overly complex designs or manual adjustments, thus improving the user experience.

[0043] The seat according to a second aspect embodiment of the present invention includes a chassis assembly 100 as described in any of the first aspect embodiments. In the prior art, the adjustment of the tilt angle of the seat cushion 102 and backrest 104 often uses a mechanical angle adjuster, while the adjustment of the seat depth also uses mechanical structures such as a limit bolt and a limit groove 605. Adjustment requires manually turning the angle adjuster or the limit bolt, then adjusting the chassis to the appropriate position before resetting the angle adjuster and the limit bolt, which is cumbersome. The chassis assembly 100 of the present invention divides the seat cushion 102 into a first shell 301 and a second shell 302. A seat depth adjustment module 103 drives the second shell 302 to rotate to achieve seat depth adjustment, and an angle adjustment module 106 drives the entire seat cushion 102 to rotate relative to the base 101 to achieve angle adjustment. The adjustment of both modules and the backrest 104 is all driven by a drive mechanism, eliminating the need for manual adjustment. The seat using this chassis assembly 100 offers a more convenient user experience.

[0044] The embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the present invention. Furthermore, the embodiments of the present invention and the features thereof can be combined with each other unless otherwise specified.

Claims

1. A chassis assembly characterized by, The base; The seat cushion is installed above the base, the seat cushion comprises a first shell and a second shell connected with each other, the first shell is rotationally connected with the base; The seat depth adjustment module connects the first shell and the second shell, the seat depth adjustment module comprises a first driving mechanism, the first driving mechanism is used for driving the second shell to move forward and backward relative to the first shell; The angle adjustment module is installed between the base and the seat cushion, the angle adjustment module comprises a second driving mechanism, the second driving mechanism is used for driving the seat cushion to rotate relative to the base; The backrest is rotationally connected with the base, the base assembly further comprises a third driving mechanism, the third driving mechanism is used for driving the backrest to rotate relative to the base. The first shell has a placing cavity, the second shell is movably installed in the placing cavity, the first shell comprises a first side plate, the second shell comprises a second side plate and a top plate connected with each other, the first side plate and the second side plate are spaced apart in the front and back direction to form a movable space, and the top plate covers the movable space.

2. The chassis assembly of claim 1, wherein, The seat depth adjustment module further comprises a worm, a worm wheel, a gear and a rack, the first driving mechanism is installed on the second shell, the output end of the first driving mechanism is connected with the worm, the worm wheel is engaged with the worm, the gear is coaxially connected with the worm wheel and connected with the second shell, the gear is engaged with the rack, the rack is arranged in the placing cavity in the front and back direction of the first shell and fixedly connected with the first shell, and the first driving mechanism drives the worm to rotate, so that the worm wheel and the gear rotate coaxially, thereby moving the gear, so that the second shell moves forward and backward relative to the first shell.

3. The chassis assembly of claim 2, wherein, The rack is arranged at the rear end of the placing cavity, the base assembly further comprises a plurality of rollers, and the plurality of rollers are spaced apart in the front and back direction and arranged at the front end of the placing cavity, and the second shell is slidably placed on the rollers.

4. The chassis assembly of claim 3, wherein, The angle adjustment module further comprises a push rod and a crank, the second driving mechanism is connected with the push rod, two ends of the crank are respectively connected with the push rod and the first shell, one end of the crank connected with the first shell is higher than the other end of the crank connected with the push rod, and the second driving mechanism is used for driving the push rod to move forward and backward, so that the crank drives the first shell to rotate relative to the base.

5. The chassis assembly of claim 1, wherein, The base comprises a third shell and a fourth shell, the third shell is slidingly connected with the fourth shell, the fourth shell is rotationally connected with the first shell, the push rod is fixedly connected with the third shell, the crank is rotationally connected with the third shell, and the second driving mechanism drives the push rod to move forward and backward, so as to drive the third shell to slide relative to the fourth shell, thereby driving the crank to rotate the first shell relative to the fourth shell.

6. The chassis assembly of claim 5, wherein, ​ 7. The chassis assembly of claim 6, wherein, The third shell is provided with a limiting slot, one end of the crank is rotationally connected in the limiting slot, the crank gradually extends out of the limiting slot from back to front, and the other end of the crank is located outside the limiting slot and rotationally connected to the first shell.

8. The chassis assembly of claim 6, wherein, The two cranks are symmetrically arranged along the width direction of the base, both of the two cranks are connected to the third shell, the push rod pushes the third shell to slide so as to make the two cranks rotate.

9. The chassis assembly of claim 1, wherein, The base assembly further comprises an output shaft, the output shaft penetrates through the base and the backrest, the output shaft is rotationally connected with the base, the backrest is fixedly connected with the output shaft, the output end of the third driving mechanism is connected with the output shaft, and the third driving mechanism is used for driving the output shaft to rotate around the axis of the output shaft, so as to make the backrest rotate relative to the base.

10. A seat, characterized by A base assembly comprising any one of claims 1-9.

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