A driving structure applied to an electric small table board of a car

Abstract

The utility model discloses a drive structure applied to electric small table board of car, including the shell, be equipped with motor and transmission assembly in the inner chamber of shell, the output of motor is equipped with worm, the worm is engaged with transmission assembly, has given transmission assembly torque transmission, transmission assembly is five stage transmission gear, wherein, primary transmission gear has self -locking function, the structure type of secondary transmission gear to four stage transmission gear is same, and two bevel gears of one big and one small constitute double coupling gear, and the output shaft of five stage transmission gear is connected with connecting shaft through the shaft coupling. The utility model under the premise of space limited can reduce transmission loss, promote transmission ratio to realize the output of big torque. Meanwhile, also has improved the lifting force and the bearing capacity of small table board to the upward, makes electric small table board more sensitive and stable in the process of operation, and the limit of bearing weight is bigger, and the security is higher.

Description

Technical Field

[0001] This utility model belongs to the field of electric small tables, specifically relating to a drive structure applied to an electric small table in a car. Background Technology

[0002] An electric tray table is a small tray table installed on the seats of vehicles, airplanes and other means of transportation. In order to enable the tray table to be electrically controlled to unfold or retract, a drive structure is installed at the bottom of the tray table. Although the existing drive structure can achieve the purpose of controlling the unfolding or retraction of the tray table, the size of the drive structure is limited by the space of the tray table. Therefore, there are problems such as low transmission ratio, low lifting force and load-bearing capacity. Utility Model Content

[0003] The purpose of this invention is to solve the aforementioned problems by providing a drive structure for an electric car tray table. This drive structure, under space constraints, can reduce transmission losses and increase the transmission ratio, thereby achieving high torque output. Furthermore, it improves the upward lifting force and load-bearing capacity of the tray table, making the electric tray table more responsive and stable during operation, with a greater weight limit and higher safety.

[0004] To achieve the above objectives, this utility model provides a drive structure for an electric car tray table, including a housing, a motor and a transmission assembly that cooperates with the motor are provided in the inner cavity of the housing, a worm gear is provided at the output end of the motor, the worm gear meshes with the transmission assembly to transmit torque, the transmission assembly is a multi-stage transmission double gear, and the last stage transmission gear has outwardly extending output shafts on both axial sides. The output shafts on both sides pass through the housing and are connected to a connecting shaft through a coupling.

[0005] The first-stage transmission gear in the multi-stage transmission double gear meshes with the worm, and the helix angle of the worm pair is less than the equivalent friction angle, which can realize the self-locking of the drive structure. Through the cooperation of the multi-stage transmission double gear, a large torque output can be achieved.

[0006] Advantages and beneficial effects of this utility model

[0007] This invention reduces transmission losses and achieves a large torque output of 27 N·m under space constraints. It also improves the upward lifting force and load-bearing capacity of the small table. The maximum upward lifting force can reach 25 kg, and the maximum load-bearing capacity can reach 800 N. This makes the electric small table more sensitive and stable during operation, with a greater weight limit and higher safety. It also improves the applicability of the small table in different scenarios and meets the diverse needs of users. Attached Figure Description

[0008] To more clearly illustrate the technical solutions in the embodiments of this utility model, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0009] Figure 1 This is a schematic diagram of the overall structure provided in the embodiment of this utility model;

[0010] Figure 2 This is a schematic diagram of the present invention after the top shell has been removed, provided in an embodiment of the present invention;

[0011] Figure 3 This is an isometric view of the present invention after removing the upper shell;

[0012] Figure 4 This is a schematic diagram of the device after removing the outer shell, provided in an embodiment of the present invention;

[0013] Figure 5 This is a schematic diagram of the transmission assembly installed in the inner cavity of the lower shell according to an embodiment of the present invention;

[0014] Figure 6 This is a schematic diagram of the meshing of the secondary transmission gear and the tertiary transmission gear provided in an embodiment of this utility model;

[0015] Figure 7 This is a schematic diagram of the upper shell structure provided in an embodiment of the present utility model;

[0016] Figure 8 This is a schematic diagram of the lower shell structure provided in an embodiment of the present utility model.

[0017] Reference numerals: Outer shell 1, Upper shell 11, Motor upper mounting cavity 111, Connecting shaft mounting bracket 112, Secondary transmission gear mounting cavity 113, Tertiary transmission gear mounting cavity 114, Fourth transmission gear mounting cavity 115, Fifth transmission gear mounting cavity 116, Connecting lug 117, Upper heat dissipation vent 118, Lower shell 12, Motor lower mounting cavity 121, Primary transmission gear mounting cavity 122, Secondary transmission gear mounting cavity 123, Tertiary transmission gear mounting cavity 124, Fourth transmission gear mounting cavity 125, Fifth transmission gear mounting cavity 126, Lower heat dissipation vent 127, Motor 2, Transmission assembly 3, Primary Transmission gear 31, worm gear 311, helical gear 312, first double gear 313, first connecting shaft 314, second-stage transmission gear 32, first large helical gear 321, first small helical gear 322, second double gear 323, second connecting shaft 324, process groove 325, third-stage transmission gear 33, second large helical gear 331, second small helical gear 332, fourth-stage transmission gear 34, third large helical gear 341, third small helical gear 342, fifth-stage transmission gear 35, fourth large helical gear 351, worm 4, output shaft 5, coupling 6, connecting shaft 7, spline 71, shim 8, motor positioning plate 9, and bearing 10. Detailed Implementation

[0018] The terms "first," "second," "third," "fourth," etc., used in the specification, claims, and accompanying drawings of this utility model are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments described herein can be implemented in a sequence other than that illustrated or described herein.

[0019] The specific embodiments of this utility model will be described in detail below with reference to the accompanying drawings. It should be noted that in the description of this utility model, the terms "upper", "lower", "left", "right", "inner", "outer", "front", "rear", etc., indicate the orientation or positional relationship based on the orientation 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.

[0020] like Figure 1 As shown, a drive structure for an electric table in a car includes a housing 1. The housing 1 is made of magnesium alloy and has the characteristics of high strength and lightweight. In order to facilitate the installation of the motor 2, transmission components and output shaft 5 in the inner cavity of the housing 1, the housing 1 is divided into an upper housing 11 and a lower housing 12.

[0021] like Figure 2As shown, the motor 2 is a brushless motor with a no-load speed of 5852 PRM and a stall torque of 972 gcm. The output shaft of the motor 2 is made of 42CrMu carburized and quenched material, which can ensure high-strength output. A worm 4 is press-fitted onto the output shaft of the motor 2. The worm 4 is made of tin bronze, which can reduce impact noise while ensuring the contact strength with the worm wheel surface and the bending strength of the tooth root. The worm 4 adopts the design parameters of 1 tooth and 0.4 module, and the helix angle is less than the equivalent friction angle. Because it has a self-locking function, the worm 4 meshes with the first-stage transmission gear 31 in the transmission assembly 3, and the torque has been transmitted to the first-stage transmission gear 31 through the worm 4.

[0022] The output shaft and worm gear 4 are press-fitted together. This ensures the synchronization of the output shaft and worm gear 4, allowing the torque generated by the motor 2 to be efficiently transmitted to the worm gear 4. Furthermore, it can withstand larger torque loads, ensuring the stability of power transmission during long-term operation of the worm gear 4. Finally, it makes assembly and quality control more convenient and faster, reduces manufacturing risks, and improves controllability.

[0023] As a further optimization, a motor positioning piece 9 is provided between the end of the motor housing near the output shaft and the inner cavity of the outer shell 1. The motor positioning piece 9 plays a role in axial positioning of the motor 2.

[0024] like Figures 2-5 As shown, the transmission assembly 3 includes a first-stage transmission gear 31, a second-stage transmission gear 32, a third-stage transmission gear 33, a fourth-stage transmission gear 34, and a fifth-stage transmission gear 35 that mesh with each other. The first-stage transmission gear 31 includes a first double gear 313 composed of a worm gear 311 and a helical gear 312. On the one hand, the worm pair formed by the worm 4 meshing with the worm gear 311 has a large transmission ratio. Through cooperation with the helical gear 312, a large degree of deceleration can be achieved within a limited driving space. By reducing the speed of the motor 2, a suitable output speed and torque can be obtained. On the other hand, the worm pair in this application has a self-locking characteristic. When it cooperates with the helical gear 312, it further enhances the self-locking capability of the drive structure, preventing the small table from falling accidentally when it is open and providing stable support for the small table. Finally, the helical gear 312 has high transmission efficiency and can accurately transmit power. The worm pair can be further optimized and adjusted during the power transmission process. The cooperation between the two can make the power transmission smoother and more efficient, reducing energy loss.

[0025] The first double gear 313 is made of 20CrMn material, which reduces costs while giving the first double gear 313 strong strength and hardness. The worm gear 311 has a design parameter of 18 teeth and a module of 0.4, and the helical gear 312 has a design parameter of 9 teeth and a module of 0.6.

[0026] The worm gear 311 and helical gear 312 are interference-fitted and connected separately by press-fitting. On the one hand, press-fitting enhances the connection strength between the two, allowing for a tighter fit between the worm gear 311 and the helical gear 312, effectively transmitting torque and ensuring efficient power transmission. On the other hand, it makes assembly more convenient, faster, and more economical. Finally, in terms of quality control, it reduces manufacturing risks and improves controllability.

[0027] After being press-fitted, the mounting holes of the first double gear 313 are coaxial, and the first connecting shaft 314 passes through the mounting holes of the first double gear 313 and connects to the inner walls of both sides of the housing 1. The first double gear 313 is rotatably connected to the first connecting shaft 314, and both ends of the first connecting shaft 314 are rotatably connected to the housing 1. This design saves space while improving the mechanical efficiency of the first-stage transmission gear 31 and reducing frictional wear when the first connecting shaft 314 rotates with the housing 1.

[0028] As a further optimization, a shim 8 is provided on the first connecting shaft 314 between the two ends of the first double gear 313 and the outer casing 1. The shim 8 can prevent the first double gear 313 from moving axially relative to the first connecting shaft 314, and also prevent the first double gear 313 from directly contacting the outer casing 1 to buffer and eliminate noise.

[0029] The motor 2 drives the primary transmission gear 31 to rotate. Specifically, the rotation of the output shaft of the motor 2 drives the worm 4, which is press-fitted with it, to rotate. The worm 4 meshes with the worm wheel 311 in the primary transmission gear 31, thereby driving the helical gear 312, which is coaxial with it, to rotate through the worm wheel 311. The helical gear 312 meshes with the first large helical gear 321 in the secondary transmission gear 32, thereby transmitting torque from the primary transmission gear 31 to the secondary transmission gear 32.

[0030] like Figures 3-5As shown, the secondary transmission gear 32, tertiary transmission gear 33, and quaternary transmission gear 34 have the same structure. The following description uses the secondary transmission gear 32 as an example. The secondary transmission gear 32 is composed of a first large helical gear 321 and a first small helical gear 322, forming a second double gear 323. The double gear design from the secondary transmission gear 32 to the quaternary transmission gear 34 can further improve the transmission efficiency of the drive structure. The first large helical gear 321 and the first small helical gear 322 are interference-fitted and connected by laser welding. Specifically, the first small helical gear 322 is a stepped gear, with outwardly extending second connecting shafts 324 on both axial sides. The small end of the stepped gear is interference-fitted with the first large helical gear 321 and connected by laser welding (see...). Figure 4 and Figure 5 The end face of the connected stepped gear is lower than the height of the mounting hole of the first large helical gear 321, forming a downwardly recessed process groove 325 (since the size of the second-stage transmission gear 32 is smaller than the size of the third-stage transmission gear 33, the position of the process groove 325 is shown more clearly). Figure 6 (The marking is made in the third-stage transmission gear 33). The process groove 325 can prevent weld scars from protruding and colliding with the second connecting shaft 324, thus ensuring that the gears can mesh and operate. The second-stage transmission gear 32 is connected to the inner cavity of the housing via the second connecting shaft 324.

[0031] As a further optimization, such as Figure 5 As shown, both ends of the second connecting shaft 324 are stepped shafts. A bearing 10 is provided between the stepped shaft and the inner cavity of the outer casing 1. The bearing 10 can be limited by the fit between the stepped surface of the stepped shaft and the inner cavity of the outer casing 1, preventing axial movement of the bearing 10. The bearing 10 can reduce the frictional loss of the second connecting shaft 324 and improve the positioning accuracy and transmission efficiency of the second-stage transmission gear 32, the third-stage transmission gear 33, and the fourth-stage transmission gear 34.

[0032] As a further optimization, the ends of the first connecting shaft 314 and the second connecting shaft 324 are both chamfered downwards to facilitate quick installation. To prevent over-positioning of the transmission assembly 3, gaps are left between the two ends of the first connecting shaft 314 and the second connecting shaft 324 and the inner cavity of the housing 1.

[0033] The secondary transmission gear 32 is made of 20CrMn material and undergoes a carburizing and quenching heat treatment process to form a hard and wear-resistant surface layer, improving its hardness and wear resistance while maintaining good internal toughness. This "hard surface, tough interior" design gives the double gear both good wear resistance and the ability to withstand certain impact loads. The design parameters of the first large helical gear 321 are 32 teeth and a module of 0.6, and the design parameters of the first small helical gear 322 are 9 teeth and a module of 0.6. The first small helical gear 322 in the secondary transmission gear 32 meshes with the second large helical gear 331 in the tertiary transmission gear 33, thus transmitting torque from the secondary transmission gear 32 to the tertiary transmission gear 33.

[0034] The structure of the third-stage transmission gear 33 is the same as that of the second-stage transmission gear 32. The difference lies in that the third-stage transmission gear 33 is made of 42CrMn material and undergoes a carburizing, quenching, and low-temperature tempering heat treatment process. This design gives it higher strength, hardness, and wear resistance, better resisting tooth surface wear and contact fatigue. The second large helical gear 331 in the third-stage transmission gear 33 has 32 teeth and a module of 0.6, while the second small helical gear 332 has 9 teeth and a module of 0.6. The second small helical gear 332 in the third-stage transmission gear 33 meshes with the third large helical gear 341 in the fourth-stage transmission gear 34, thus transmitting torque from the third-stage transmission gear 33 to the fourth-stage transmission gear 34.

[0035] The structure, material, and heat treatment process of the fourth-stage transmission gear 34 are the same as those of the third-stage transmission gear 33. The difference lies in that the third large helical gear 341 in the fourth-stage transmission gear 34 has a design parameter of 32 teeth and a module of 0.6, while the third small helical gear 342 has a design parameter of 7 teeth and a module of 1.25. The third small helical gear 342 in the fourth-stage transmission gear 34 meshes with the fourth large helical gear 351 in the fifth-stage transmission gear 35, thus transmitting torque from the fourth-stage transmission gear 34 to the fifth-stage transmission gear 35.

[0036] like Figure 3 and Figure 4 As shown, the five-stage transmission gear 35 includes a fourth large helical gear 351. The five-stage transmission gear 35 is made of 42CrMn material and undergoes a carburizing, quenching, and low-temperature tempering heat treatment process. It adopts a design parameter of 13 teeth and a module of 1.25. The fourth large helical gear 351 has outwardly extending output shafts 5 on both axial sides. The output shafts 5 pass through the housing 1 and are connected to the connecting shaft 7 via a coupling 6. The connecting shaft 7 has a spline 71 that connects to the small table. The torque is ultimately transmitted to the small table through the connecting shaft 7 to drive the small table to open or close.

[0037] In this application, the output shaft 5 and the connecting shaft 7 are connected separately by a coupling 6. On the one hand, this is to achieve the assemblability of the overall drive structure and the small table. On the other hand, the connection by the coupling 6 can ensure the coaxiality of the output shaft 5 and the connecting shaft 7, thereby ensuring transmission accuracy.

[0038] As a further optimization, such as Figure 5 As shown, the output shaft 5 is positioned relative to the housing 1 as a stepped shaft, and a bearing 10 is mounted on the stepped shaft. The bearing 10 is axially limited by the fit between the stepped surface of the output shaft 5 and the inner cavity of the housing 1. The bearing 10 can reduce the frictional loss of the output shaft 5 during rotation and improve the positioning accuracy and transmission efficiency of the five-stage transmission gear 35.

[0039] In this application, all gears in the transmission component 3 are helical gears. Helical gears can improve transmission efficiency, which is 95%-98%, improve load-bearing capacity, and reduce transmission loss.

[0040] Due to the size limitation of the small tabletop, the motor size is relatively small, making it difficult to generate a large amount of torque. Therefore, structurally, this application employs a five-stage transmission. The first stage uses a worm gear pair and helical gears, which not only enables the drive structure to achieve overall self-locking after deployment but also accurately transmits power. The second to fourth stages use a double-gear configuration with one large and one small helical gear, further improving transmission efficiency and reducing transmission losses. To reduce frictional losses in the first-stage transmission gear within the confined space, this application uses a first double-gear 313 rotatably connected to a first connecting shaft 314, which in turn is rotatably connected to the outer casing 1, improving the efficiency of the transmission. To improve mechanical efficiency and reduce friction loss, bearings 10 are used on the second-stage transmission gears 32 to the fifth-stage transmission gears 35 to reduce friction loss and improve transmission efficiency. In terms of process, the output shaft of the motor 2 is press-fitted to the worm gear 4, and the worm wheel and helical gear in the first-stage transmission gears are also press-fitted, which enables torque to be effectively transmitted and provides stability for power transmission. The large helical gear and small helical gear in the second-stage transmission gears 32 to the fourth-stage transmission gears 34 are connected by laser welding after interference fit, which can further improve transmission efficiency. Ultimately, a large torque output is achieved in a confined space, which improves the lifting force of the drive structure on the small table and the load-bearing capacity of the small table.

[0041] To describe in detail how the motor 2, transmission assembly 3, and output shaft 5 are installed in the inner cavity of the housing 1, the upper housing 11 and the lower housing 12 will be explained separately.

[0042] like Figure 7As shown, the upper shell 11 is a shell near the small table. Its inner cavity is provided with a motor mounting cavity 111, a connecting shaft mounting bracket 112 located on the left and right sides of the output shaft, a secondary transmission gear mounting cavity 113, a tertiary transmission gear mounting cavity 114, a quaternary transmission gear mounting cavity 115, and a quinary transmission gear mounting cavity 116 in sequence. The upper shell 11 is provided with connecting ears 117 around its perimeter. The outer shell 1 is connected to the bottom of the small table through the connecting ears 117.

[0043] like Figure 8 As shown, the lower shell 12 is the shell on the side away from the small table. Its inner cavity contains, in sequence, a motor lower mounting cavity 121, a first-stage transmission gear mounting cavity 122 located at the end of the output shaft, a second-stage transmission gear mounting cavity 123, a third-stage transmission gear mounting cavity 124, a fourth-stage transmission gear mounting cavity 125, and a fifth-stage transmission gear mounting cavity 126. After the upper shell 11 and lower shell 12 are screwed together, the motor 2 is installed in the contoured inner cavity formed by the connection of the upper motor mounting cavity 111 and the lower motor mounting cavity 121. The first-stage transmission gear 31 is rotatably connected to the contoured inner cavity formed by the connection of the connecting shaft mounting bracket 112 and the first-stage transmission gear mounting cavity 122 through mounting holes. Bearings 10 are installed at both ends of the second connecting shaft of the second-stage transmission gear 32. After installation, the second-stage transmission gear 32 is installed in the second-stage transmission gear mounting upper cavity 113 and the second-stage transmission gear mounting cavity 126. In the contoured inner cavity after the lower cavity 123 is connected, bearings 10 are installed at both ends of the second connecting shaft of the third-stage transmission gear 33. The installed third-stage transmission gear 33 is installed in the contoured inner cavity after the upper cavity 114 and the lower cavity 124 of the third-stage transmission gear are connected. Bearings 10 are installed at both ends of the second connecting shaft of the fourth-stage transmission gear 34. The installed fourth-stage transmission gear 34 is installed in the contoured inner cavity after the upper cavity 115 and the lower cavity 125 of the fourth-stage transmission gear are connected. Bearings 10 are installed at both ends of the second connecting shaft of the fifth-stage transmission gear 35. The installed fifth-stage transmission gear 35 is installed in the contoured inner cavity after the upper cavity 116 and the lower cavity 126 of the fifth-stage transmission gear are connected. The output shaft 5 of the fifth-stage transmission gear 35 extends outward through the outer shell 1 and is connected to the connecting shaft 7 through the coupling 6.

[0044] In order to prevent the motor 2 from accumulating a large amount of heat inside the housing 1 during operation, this application provides a lower heat dissipation port 127 on the lower mounting cavity 121 of the motor and an upper heat dissipation port 118 on the upper mounting cavity 111 of the motor.

[0045] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present utility model, and are not intended to limit them. Although the present utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the present utility model.

Claims

1. A drive structure for an electric table in a car, comprising a housing (1), wherein a motor (2) and a transmission assembly (3) cooperating with the motor (2) are disposed in the inner cavity of the housing (1), characterized in that: The output end of the motor (2) is provided with a worm (4), which meshes with the transmission assembly (3) to transmit torque. The transmission assembly (3) is a multi-stage transmission double gear. The last stage transmission gear has outwardly extending output shafts (5) on both sides of its axial direction. The output shafts (5) on both sides pass through the outer casing (1) and are connected to the connecting shaft (7) through the coupling (6). The first-stage transmission gear (31) of the multi-stage transmission double gear meshes with the worm (4), and the helix angle of the worm pair is less than the equivalent friction angle, which can realize the self-locking of the drive structure. Through the cooperation of the multi-stage transmission double gear, a large torque output can be achieved.

2. The driving structure for an electric car tray table according to claim 1, characterized in that: The transmission assembly (3) is a five-stage double gear system, including a first-stage transmission gear (31), a second-stage transmission gear (32), a third-stage transmission gear (33), a fourth-stage transmission gear (34), and a fifth-stage transmission gear (35) that mesh with each other. The first-stage transmission gear (31) includes a first double gear (313) composed of a worm gear (311) and a helical gear (312). The worm (4) meshes with the worm gear (311) in the first-stage transmission gear (31) to form a worm pair. The second-stage transmission gear (32), the third-stage transmission gear (33), and the fourth-stage transmission gear (34) have the same structural type, all including a second double gear composed of a large helical gear and a small helical gear. The helical gear in the first-stage transmission gear (31) (312) meshes with the first large helical gear (321) in the second-stage transmission gear (32), the first small helical gear (322) in the second-stage transmission gear (32) meshes with the second large helical gear (331) in the third-stage transmission gear (33), the second small helical gear (332) in the third-stage transmission gear (33) meshes with the third large helical gear (341) in the fourth-stage transmission gear (34), and the third small helical gear (342) in the fourth-stage transmission gear (34) meshes with the fourth large helical gear (351) in the fifth-stage transmission gear (35). The fourth large helical gear (351) has outwardly extending output shafts (5) at both ends of its axial direction. The transmission assembly (3) drives the load connected to it through the output shafts (5).

3. The driving structure for an electric car tray table according to claim 1, characterized in that: The output shaft of the motor (2) is connected to the worm gear (4) by press fitting.

4. The driving structure for an electric car tray table according to claim 2, characterized in that: The worm gear (311) and helical gear (312) are interference-fitted and connected separately by press fitting.

5. The driving structure for an electric car tray table according to claim 2, characterized in that: The first connecting shaft (314) is rotatably connected in the mounting hole of the first double gear (313), and the two ends of the first connecting shaft (314) are rotatably connected to the inner walls of both sides of the outer casing (1).

6. The driving structure for an electric car tray table according to claim 5, characterized in that: Shims (8) are provided on the first connecting shaft (314) between the two ends of the first double gear (313) and the outer casing (1).

7. The drive structure for an electric car tray table according to claim 1, characterized in that: A motor positioning piece (9) is provided between the end of the motor housing near the output shaft and the inner cavity of the outer shell (1).

8. The driving structure for an electric car tray table according to claim 2, characterized in that: The large helical gear and small helical gear in the secondary transmission gear (32), tertiary transmission gear (33), and quaternary transmission gear (34) are connected by laser welding after interference fit.

9. The driving structure for an electric car tray table according to claim 8, characterized in that: The small helical gear in the second-stage transmission gear (32), third-stage transmission gear (33), and fourth-stage transmission gear (34) is a stepped gear. One end of the stepped gear is interference-fitted with the large helical gear and connected by laser welding. The end face of the stepped gear at the connecting end is lower than the height of the mounting hole of the large helical gear, forming a downward recessed process groove (325). The stepped gear has a second connecting shaft (324) extending outward on both sides of its axial direction. The second-stage transmission gear (32), third-stage transmission gear (33), and fourth-stage transmission gear (34) are connected to the inner cavity of the outer shell (1) through the second connecting shaft (324).

10. The driving structure for an electric table in a car according to claim 2, characterized in that: The second-stage transmission gear (32), the third-stage transmission gear (33), and the fourth-stage transmission gear (34) have second connecting shafts (324) on both sides of the axial direction. Bearings (10) are provided on the output shafts (5) on both sides of the second connecting shafts (324) and the fifth-stage transmission gear (35). The two ends of the second connecting shaft (324) are stepped shafts, and the position of the output shaft (5) relative to the bearing (10) is also a stepped shaft. The axial direction of the bearing (10) is limited by the cooperation between the stepped surfaces of the second connecting shaft (324) and the output shaft (5) and the inner cavity of the outer shell (1).

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