Speed-changing gear box

Abstract

The utility model relates to a speed-changing gear box which comprises a shell, and a containing cavity is formed in the shell. An output shaft of the motor extends into the accommodating cavity from the first end of the accommodating cavity; the transmission assembly comprises a transmission gear set and an output gear, the transmission gear set is located in the containing cavity, the input end of the transmission gear set is connected with an output shaft of the motor, and the output gear is connected with the output end of the transmission gear set; the output gear comprises a circular disc part and tooth parts which are distributed on the circumference of the disc part and protrude in the radial direction of the disc part, the disc part is located in the containing cavity, and the part, corresponding to the central angle of the disc part, of each tooth part is larger than or equal to 180 degrees and smaller than 270 degrees extends out of the second end of the containing cavity. The speed-changing gear box has good application flexibility in different application scenes, dust and other impurities entering the speed-changing gear box can be reduced, and the service life of the speed-changing gear box is prolonged.

Description

TECHNICAL FIELD

[0001] The utility model relates to mechanical field, concretely relates to a gear transmission. BACKGROUND

[0002] Gear transmission is a kind of mechanical device that realizes speed change through gear combination, plays an important role in modern mechanical transmission, and its diversified type and extensive application make it meet the power transmission demand in different scenes, and it is widely used in electric appliance, automobile, industrial equipment and other fields.Gear transmission can output power through rotating shaft or through gear, and for the application of gear transmission in electric appliance, gear transmission is needed to output power through gear in some scenes, and the output gear for outputting power in gear transmission can be directly connected with the rotating disc in electric appliance, to realize the rotation of rotating disc, for example, can be used for rotating decorative lighting, rotating disc in microwave oven and other electric appliances.

[0003] However, most of the existing gear transmissions only extend a small number of teeth outward, to avoid interference with the shell, the rotating disc and other devices connected with the gear can only be arranged at a specific angle and specific position to cooperate with the output gear, or for the rotating disc at fixed position, the gear transmission can only be installed at a specific position to realize the cooperation of the output gear and the rotating disc, and to accommodate and install the gear transmission, the structure of the electric appliance needs to be greatly changed, which increases the development cost and limits the applicable scenarios of the gear transmission.

[0004] In addition, if the gear has more teeth extending out of the gear transmission to cooperate with other devices, the exposed part of the output gear is more, which makes dust and other impurities more easily enter the gear transmission, affecting the service life of the gear transmission. UTILITY MODEL CONTENTS

[0005] In view of the deficiencies of the prior art, the utility model aims at providing a gear transmission, which has good applicability and flexibility in different application scenarios, and can reduce the entry of dust and other impurities into the gear transmission, and improve the service life of the gear transmission.

[0006] To achieve the purpose of the utility model, the utility model provides a gear transmission box, it includes: the shell, the shell is formed in the accommodation cavity, motor, the output shaft of the motor is from the first end of the accommodation cavity and goes into the accommodation cavity, transmission assembly, the transmission assembly includes transmission gear set and output gear, the transmission gear set is located in the accommodation cavity, the input end of the transmission gear set is connected with the output shaft of the motor, the output gear is connected with the output end of the transmission gear set, the output gear includes the disc part of circular and the tooth part that is arranged in the circumference of the disc part and is protruding along the radial direction of the disc part, the disc part is located in the accommodation cavity, the part of the tooth part corresponding to the disc part center angle greater than or equal to 180 DEG and less than 270 DEG goes out from the second end of the accommodation cavity.

[0007] In some embodiments of the utility model, the shell includes first shell and second shell, the first shell includes first plate body, second plate body and first enclosure, the first plate body and the second plate body are ladder-shaped, the second plate body is closer to the second shell relative to the first plate body, the first enclosure connects the first plate body and the second plate body and surrounds the first plate body and the second plate body, the second shell includes third plate body, fourth plate body and second enclosure, the third plate body and the fourth plate body are ladder-shaped, the fourth plate body is farther away from the first shell relative to the second plate body, the second enclosure connects the third plate body and the fourth plate body and is arranged around the third plate body, the second enclosure forms a gap around the fourth plate body, the first enclosure is connected with the second enclosure, the first plate body is opposite to the third plate body, the second plate body is opposite to the fourth plate body, the output gear is located between the second plate body and the fourth plate body, the gap is limited between the fourth plate body and the first enclosure, part of the tooth part goes out from the gap, and the transmission gear set is hidden relative to the gap.

[0008] In some embodiments of the utility model, the thickness of the output gear is less than the height difference between the third plate body and the fourth plate body, and the thickness of the output gear is less than the distance between the fourth plate body and the first enclosure.

[0009] In some embodiments of the utility model, one of the first enclosure and the second enclosure has a convex part and the other has a concave part, and the convex part is matched with the concave part.

[0010] In some embodiments of the utility model, the second enclosure on both sides of the gap is provided with a first matching hole, the first enclosure is provided with a second matching hole opposite to the first matching hole, and the first matching hole and the second matching hole are connected by a first threaded fastener.

[0011] In some embodiments of the utility model, still be equipped with third cooperation hole on first surrounding board or first board body located transmission gear group both sides, still be equipped with fourth cooperation hole with third cooperation hole opposite on second surrounding board or third board body, third cooperation hole and fourth cooperation hole are connected by second threaded fastener.

[0012] In some embodiments of the utility model, the transmission gear set includes a worm, a worm wheel, a plurality of transmission gears and a plurality of mandrels, the worm is circumferentially linked and sleeved on the output shaft of the motor, the worm wheel is engaged with the worm, a plurality of the mandrels are parallel to each other and connected between the first housing and the second housing respectively, each of the mandrels is connected with one of the transmission gears or two circumferentially linked transmission gears, one of the transmission gears is connected with the worm wheel on the same mandrel, and the other transmission gear is connected with the output gear on the other mandrel, wherein the transmission gears on different mandrels are sequentially connected from the transmission gear connected with the worm wheel to the transmission gear connected with the output gear.

[0013] In some embodiments of the utility model, at least one of the mandrels is sleeved with two circumferentially linked transmission gears, the worm wheel and all the transmission gears are respectively arranged in one of the two circumferentially linked transmission gears, and the housing is arranged around the transmission gear set.

[0014] In some embodiments of the utility model, the first plate body, the second plate body, the third plate body and the fourth plate body are respectively provided with a boss and a groove in the boss, the groove of the first plate body is opposite to the groove of the third plate body, the groove of the second plate body is opposite to the groove of the third plate body, and the two ends of the mandrel are fixed in the corresponding grooves.

[0015] In some embodiments of the utility model, the transmission gear includes first gear, second gear, third gear, fourth gear, fifth gear, sixth gear and seventh gear, the mandrel includes first mandrel, second mandrel, third mandrel, fourth mandrel and fifth mandrel, the first gear and the worm gear are circumferentially linked and arranged on the first mandrel, the second gear and the third gear are circumferentially linked and arranged on the second mandrel, the fourth gear and the fifth gear are circumferentially linked and arranged on the third mandrel, the sixth gear is arranged on the fourth mandrel, the fifth gear and the output gear are circumferentially linked and arranged on the fifth mandrel, the first gear is engaged with the second gear, the third gear is engaged with the fourth gear, the fifth gear is engaged with the sixth gear, and the sixth gear is engaged with the seventh gear.

[0016] In some embodiments of the utility model, the worm gear, the third gear and the fourth gear are aligned, and the first gear, the second gear, the fifth gear, the sixth gear and the seventh gear are aligned.

[0017] In some embodiments of the utility model, the first gear is relative to the worm gear, the third gear is relative to the second gear, the fifth gear is relative to the fourth gear, and the output gear is relative to the seventh gear, all of which are tooth number increase or tooth number decrease.

[0018] In some embodiments of the utility model, the first end of the accommodating cavity is opposite to the second end of the accommodating cavity, and the first mandrel, the second mandrel, the third mandrel, the fourth mandrel and the fifth mandrel are distributed on both sides of the line from the first end of the accommodating cavity to the second end of the accommodating cavity.

[0019] In some embodiments of the utility model, the motor is connected to the side surface of the shell, the thickness of the shell is less than the thickness of the motor, and the shell is provided with a convex block which is transitioned to the motor shell of the motor in a circular arc and is flush with the motor shell.

[0020] In some embodiments of the utility model, the motor is connected to the shell through a third threaded fastener.

[0021] In some embodiments of the utility model, the shell is connected with a mounting plate, and the mounting plate is provided with a mounting hole.

[0022] Compared with the prior art, the utility model can achieve the following beneficial effects:

[0023] The gear transmission box utilizes the accommodating cavity formed by the shell to accommodate the transmission gear set, the output shaft of the motor is connected with the transmission gear set, the transmission gear set is connected with the output gear, and the transmission of power and the change of speed are realized. BRIEF DESCRIPTION OF DRAWINGS

[0024] Figure 1 is a three-dimensional structure schematic diagram of the gear transmission box embodiment of the utility model.

[0025] Figure 2 is a three-dimensional structure schematic diagram of the gear transmission box embodiment of the utility model.

[0026] Figure 3 is a three-dimensional structure schematic diagram of the gear transmission box embodiment of the utility model.

[0027] Figure 4 is a structure exploded schematic diagram of the gear transmission box embodiment of the utility model.

[0028] Figure 5 is a structure exploded schematic diagram of the gear transmission box embodiment of the utility model.

[0029] Figure 6 is a structure schematic diagram of the transmission assembly in the gear transmission box embodiment of the utility model.

[0030] Figure 7 is a structure schematic diagram of the transmission assembly in the gear transmission box embodiment of the utility model.

[0031] Figure 8 is a structure schematic diagram of the transmission assembly in the gear transmission box embodiment of the utility model.

[0032] In the figure, the shell 100, the accommodating cavity 110, the first shell 120, the first plate body 121, the second plate body 122, the first baffle 123, the second shell 130, the third plate body 131, the fourth plate body 132, the second baffle 133, the notch 134, the convex part 135, the concave part 136, the first matching hole 140, the second matching hole 141, the first threaded fastener 142, the third matching hole 150, the fourth matching hole 151, the second threaded fastener 152, the boss 160, the groove 161, the reinforcing rib 162, the convex block 170, the mounting plate 180, the mounting hole 181; the motor 200, the output shaft 210; the transmission assembly 300, the output gear 310, the disc part 311, the tooth part 312, the transmission gear 350 group 320, the worm 330, the worm wheel 340, the transmission gear 350, the first gear 351, the second gear 352, the third gear 353, the fourth gear 354, the fifth gear 355, the sixth gear 356, the seventh gear 357, the mandrel 360, the first mandrel 361, the second mandrel 362, the third mandrel 363, the fourth mandrel 364, the fifth mandrel 365.

[0033] The utility model will be further explained in detail below in combination with the drawings and specific embodiments. Specific embodiments

[0034] As Figures 1 to 8 shown, the embodiment of the utility model provides a gear transmission box, the gear transmission box can change the rotating speed of motor 200 by transmission assembly 300, and realizes power transmission by the tooth part 312 of the part of output gear 310 exposed to the shell 100 and other components cooperation. The gear transmission box of this embodiment is suitable for electric appliances and other various scenes needing to change speed.

[0035] Specifically, the gear transmission box of the embodiment includes a shell 100, a motor 200 and a transmission assembly 300.

[0036] The accommodating cavity 110 is formed in the shell 100, and the accommodating cavity 110 is a cavity that can accommodate other components. The shell 100 can support and protect other components. The shell 100 can be made of plastic or metal.

[0037] The output shaft 210 of the motor 200 extends into the accommodating cavity 110 from the first end of the accommodating cavity 110. The body of the motor 200 can be arranged outside the shell 100, which is convenient for fixing, detecting and replacing the motor 200. The motor 200 can be a direct current or alternating current drive, and can be an internal rotor motor. The output shaft 210 is connected with the body of the motor 200, and the output shaft 210 rotates under the drive of the body of the motor 200.

[0038] The transmission assembly 300 includes a transmission gear set 320 and an output gear 310, the transmission gear set 320 is located in the accommodating cavity 110, the input end of the transmission gear set 320 is connected with the output shaft 210 of the motor 200, the output gear 310 is connected with the output end of the transmission gear set 320, the transmission gear set 320 is used for transmitting the rotation of the output shaft 210 to the output gear 310 and changing the rotation speed. The transmission assembly 300 can be made of plastic or metal.

[0039] The output gear 310 includes a circular disc part 311 and a tooth part 312 arranged on the circumference of the disc part 311 and protruding along the radial direction of the disc part 311, the tooth part 312 can be straight teeth or helical teeth, and the tooth part 312 can be uniformly distributed on the circumference of the disc part 311.

[0040] The disc part 311 is located in the accommodating cavity 110, and the part of the tooth part 312 corresponding to the central angle of the disc part 311 greater than or equal to 180° and less than 270° protrudes from the second end of the accommodating cavity 110, the protruding part can cooperate with other devices in the scene of its application, and the central angle of the disc part 311 corresponding to the tooth part 312 protruding from the second end of the accommodating cavity 110 can be 180°, 190°, 200°, 210°, 220°, 230°, 240°, 250°, 260°, etc. If the corresponding central angle is too large, the support and protection of the shell 100 on the output gear 310 will be reduced, and if the corresponding central angle is too small, the range of the output gear 310 that can cooperate with other devices in the scene of its application will be reduced. The part of the tooth part 312 corresponding to the central angle of the disc part 311 greater than or equal to 180° and less than 270° can cooperate with devices such as the rotating disc of an electric appliance in a larger position range and a larger angle range, so that the gear transmission box has better application flexibility in different application scenarios. For example, for the rotating disc fixed in position in an electric appliance, the tooth part 312 of the output gear 310 protruding from the second end of the accommodating cavity 110 can be made to cooperate with the rotating disc, and the gear transmission box can be determined to be in a suitable position in the electric appliance while maintaining cooperation between the tooth part 312 and the rotating disc, which facilitates the selection and installation of the position of the gear transmission box and avoids major changes to the structure of the electric appliance.

[0041] Moreover, the disc part 311 of the output gear 310 is accommodated in the accommodating cavity 110, and only part of the tooth part 312 is exposed outside the accommodating cavity 110, which avoids excessive exposure of the output gear 310 and reduces dust accumulation on the output gear 310, thereby reducing the entry of dust and other impurities into the gear transmission box and improving the service life of the gear transmission box.

[0042] In some examples, the shell 100 includes a first shell 120 and a second shell 130, and the two shells are combined to form the shell, which is conducive to the installation of the motor 200, the transmission assembly 300, etc. In some examples, the shell 100 includes a first shell 120 and a second shell 130, and the two shells are combined to form the shell, which is conducive to the installation of the motor 200, the transmission assembly 300, etc.

[0043] In some examples, the first shell 120 includes a first plate body 121, a second plate body 122, and a first surrounding plate 123, the first plate body 121 and the second plate body 122 are stepped, the second plate body 122 is closer to the second shell 130 relative to the first plate body 121, and the stepped arrangement of the first plate body 121 and the second plate body 122 can cooperate with the transmission assembly 300, so that the first shell 120 is more fitted to the arrangement of the transmission assembly 300, and the space waste is reduced. The first surrounding plate 123 connects the first plate body 121 and the second plate body 122 and surrounds the first plate body 121 and the second plate body 122, and a stepped cavity is formed inside the first plate body 121, the second plate body 122, and the first surrounding plate 123, which constitutes part of the accommodation cavity 110.

[0044] The second shell 130 includes a third plate body 131, a fourth plate body 132, and a second surrounding plate 133, the third plate body 131 and the fourth plate body 132 are stepped, the fourth plate body 132 is farther away from the first shell 120 relative to the second plate body 122, and the stepped arrangement of the third plate body 131 and the fourth plate body 132 can cooperate with the transmission assembly 300, so that the second shell 130 is more fitted to the arrangement of the transmission assembly 300, and the space waste is reduced. The second surrounding plate 133 connects the third plate body 131 and the fourth plate body 132 and is arranged around the third plate body 131, and the second surrounding plate 133 forms a gap 134 around the fourth plate body 132, and the gap 134 is used for the tooth part 312 to extend out of the shell 100.

[0045] The first surrounding plate 123 is connected with the second surrounding plate 133, the first plate body 121 is opposite to the third plate body 131, and the second plate body 122 is opposite to the fourth plate body 132, so as to form the accommodation cavity 110. Most of the transmission gear set 320 is arranged between the first plate body 121 and the third plate body 131, the output gear 310 is located between the second plate body 122 and the fourth plate body 132, the gap 134 is limited between the fourth plate body 132 and the first surrounding plate 123, part of the tooth part 312 extends out of the gap 134, and the transmission gear set 320 is hidden relative to the gap 134. Through the above arrangement, it is more difficult for dust and other impurities to enter the transmission gear set 320 through the stepped shape, and the influence of dust on the gear transmission box is reduced.

[0046] In some examples, the thickness of the output gear 310 is less than the height difference between the third plate body 131 and the fourth plate body 132, avoiding that the gap 134 directly leads to the accommodation cavity 110 between the first plate body 121 and the third plate body 131, so as to better prevent dust. The thickness of the output gear 310 is less than the distance between the fourth plate body 132 and the first surrounding plate 123, i.e., the width of the gap 134, avoiding that the gap 134 affects the rotation of the output gear 310.

[0047] In some examples, one of the first and second enclosing plates 123 and 133 has a protrusion 135 and the other has a recess 136, the protrusion 135 and the recess 136 cooperate to facilitate the positioning and fitting between the first and second enclosing plates 123 and 133.

[0048] In some examples, the second enclosing plate 133 on both sides of the gap 134 is provided with a first fitting hole 140, and the first enclosing plate 123 is provided with a second fitting hole 141 opposite the first fitting hole 140, the first fitting hole 140 and the second fitting hole 141 are connected by a first threaded fastener 142, thereby improving the bonding strength between the second plate body 122 and the fourth plate body 132, avoiding warping of the second plate body 122 and the fourth plate body 132, and avoiding disengagement of the output gear 310 from the gap 134. One of the first fitting hole 140 and the second fitting hole 141 can be a through hole, and the other can be a blind hole.

[0049] In some examples, the first enclosing plate 123 or the first plate body 121 on both sides of the transmission gear set 320 is further provided with a third fitting hole 150, and the second enclosing plate 133 or the third plate body 131 is further provided with a fourth fitting hole 151 opposite the third fitting hole 150, the third fitting hole 150 and the fourth fitting hole 151 are connected by a second threaded fastener 152, thereby improving the connection strength of the first housing 120 and the second housing 130, and avoiding loosening of the first housing 120 and the second housing 130. One of the third fitting hole 150 and the fourth fitting hole 151 can be a through hole, and the other can be a blind hole.

[0050] In some examples, the transmission gear set 320 includes a worm 330, a worm wheel 340, a plurality of transmission gears 350, and a plurality of shafts 360, the worm 330 is circumferentially connected to the output shaft 210 of the motor 200, the worm wheel 340 is engaged with the worm 330, thereby converting the rotation of the output shaft 210 in a first direction into the rotation of the worm wheel 340 in a second direction. The plurality of shafts 360 are parallel to each other and connected between the first housing 120 and the second housing 130, each shaft 360 connects one transmission gear 350 or two transmission gears 350 circumferentially connected, one of the transmission gears 350 is connected to the same shaft 360 as the worm wheel 340, and the other transmission gear 350 is connected to another shaft 360 as the output gear 310; taking the transmission gear 350 connected to the worm wheel 340 as the head and the transmission gear 350 connected to the output gear 310 as the tail, the transmission gears 350 on different shafts 360 are sequentially engaged, thereby realizing rotation transmission from the worm wheel 340 to the output gear 310.

[0051] In some examples, two transmission gears 350 are arranged on at least one mandrel 360 in a circumferential linkage, the two transmission gears 350 on the same mandrel 360 can have different gear diameters and tooth numbers, so that the size and rotation speed of the gear box can be adjusted. The worm gear 340 and all the transmission gears 350 are arranged respectively in one of the two transmission gears 350 in a circumferential linkage, and the housing is arranged around the transmission gear set 320, so that the worm gear 340 and all the transmission gears 350 are mainly concentrated between two gear thicknesses, reducing the overall thickness of the gear box, saving the space occupied by the gear box, and facilitating the application of the gear box. The output gear 310 is arranged staggered with the two transmission gears 350 in a circumferential linkage, and the output gear 310 is arranged in a separate layer, so that the gap 134 only corresponds to the output gear 310, avoiding the transmission gears 350 from being contaminated by dust.

[0052] In some examples, the first plate body 121, the second plate body 122, the third plate body 131 and the fourth plate body 132 are respectively provided with bosses 160 and grooves 161 in the bosses 160, the grooves 161 of the first plate body 121 and the third plate body 131 are opposite, the grooves 161 of the second plate body 122 and the third plate body 131 are opposite, and the two ends of the mandrel 360 are fixed in the corresponding grooves 161, so as to realize the positioning of the mandrel 360 and facilitate the installation of the mandrel 360. The bosses 160 of the first plate body 121 and the second plate body 122 are provided with reinforcing ribs 162, or the bosses 160 of the third plate body 131 and the fourth plate body 132 are provided with reinforcing ribs 162, and the bosses 160 provided with the reinforcing ribs 162 can have a higher boss 160 height.

[0053] In some examples, the transmission gear 350 includes a first gear 351, a second gear 352, a third gear 353, a fourth gear 354, a fifth gear 355, a sixth gear 356 and a seventh gear 357, and the mandrel 360 includes a first mandrel 361, a second mandrel 362, a third mandrel 363, a fourth mandrel 364 and a fifth mandrel 365. The use of multiple transmission gears 350 and multiple mandrels 360 is conducive to improving the transmission ratio. The first gear 351 and the worm gear 340 are in a circumferential linkage and arranged on the first mandrel 361, the second gear 352 and the third gear 353 are in a circumferential linkage and arranged on the second mandrel 362, the fourth gear 354 and the fifth gear 355 are in a circumferential linkage and arranged on the third mandrel 363, the sixth gear is arranged on the fourth mandrel 364, and the fifth gear 355 and the output gear 310 are in a circumferential linkage and arranged on the fifth mandrel 365; the first gear 351 and the second gear 352 are engaged, the third gear 353 and the fourth gear 354 are engaged, the fifth gear 355 and the sixth gear 356 are engaged, and the sixth gear 356 and the seventh gear 357 are engaged, realizing multi-stage transmission and facilitating the arrangement of the positions of the transmission gears 350.

[0054] In some examples, the worm gear 340, the third gear 353 and the fourth gear 354 are aligned, and the first gear 351, the second gear 352, the fifth gear 355, the sixth gear 356 and the seventh gear 357 are aligned, so that the transmission gear 350 is concentrated between two layers of gear thickness, reducing the thickness of the gear transmission box.

[0055] In some examples, the first gear 351 is increased or decreased in the number of teeth relative to the worm gear 340, the third gear 353 is increased or decreased in the number of teeth relative to the second gear 352, the fifth gear 355 is increased or decreased in the number of teeth relative to the fourth gear 354, and the output gear 310 is increased or decreased in the number of teeth relative to the seventh gear 357, so as to realize the increase or decrease of the transmission speed of the entire gear transmission box.

[0056] In some examples, the first end of the accommodating cavity 110 is opposite to the second end of the accommodating cavity 110, and the motor 200 and the output gear 310 are arranged at two ends of the shell 100, so as to avoid the motor 200 from blocking the contact of other devices with the tooth part 312 of the output gear 310.

[0057] In some examples, the first core shaft 361, the second core shaft 362, the third core shaft 363, the fourth core shaft 364 and the fifth core shaft 365 are distributed on both sides of the line from the first end of the accommodating cavity 110 to the second end of the accommodating cavity 110, so that the transmission gear 350 is more reasonably arranged, and the size from the first end of the accommodating cavity 110 to the second end of the accommodating cavity 110 is prevented from being too long.

[0058] In some examples, the motor 200 is connected to the side surface of the shell 100, the thickness of the shell 100 is less than the thickness of the motor 200, and the shell 100 is provided with a convex block 170 that is transitioned by a circular arc and is flush with the motor 200 shell of the motor 200, so as to avoid the motor 200 from protruding from the shell 100 and being easily damaged by collision.

[0059] In some examples, the motor 200 is connected to the shell 100 through the third threaded fastener, so as to realize the fixation of the motor 200.

[0060] In some examples, the shell 100 is connected with a mounting plate 180, and the mounting plate 180 is provided with a mounting hole 181, which is used to be connected to the object to which it is applied, such as the inside of an electrical appliance shell, through the fourth threaded fastener.

[0061] Finally, it should be emphasized that the above description is only the preferred embodiment of the present application, and is not used to limit the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A gear change gearbox characterised in that The gear box comprises: a housing, a receiving cavity is formed in the housing; a motor, an output shaft of the motor extends into the receiving cavity from a first end of the receiving cavity; a transmission assembly, the transmission assembly comprises a transmission gear set and an output gear, the transmission gear set is located in the receiving cavity, an input end of the transmission gear set is connected with the output shaft of the motor, the output gear is connected with an output end of the transmission gear set, the output gear comprises a circular disc part and a tooth part, the circular disc part is located in the receiving cavity, a part of the tooth part corresponding to a central angle of the circular disc part greater than or equal to 180° and less than 270° extends out of a second end of the receiving cavity.

2. The gear box according to claim 1, wherein: the housing comprises a first housing and a second housing; the first housing comprises a first plate, a second plate and a first surrounding plate, the first plate and the second plate are stepped, the second plate is closer to the second housing than the first plate, the first surrounding plate connects the first plate and the second plate and surrounds the first plate and the second plate; the second housing comprises a third plate, a fourth plate and a second surrounding plate, the third plate and the fourth plate are stepped, the fourth plate is farther away from the first housing than the second plate, the second surrounding plate connects the third plate and the fourth plate and is located around the third plate, the second surrounding plate forms a gap around the fourth plate; the first surrounding plate is connected with the second surrounding plate, the first plate is opposite to the third plate, the second plate is opposite to the fourth plate, the output gear is located between the second plate and the fourth plate, the gap is limited between the fourth plate and the first surrounding plate, the part of the tooth part extends out of the gap, and the transmission gear set is hidden relative to the gap.

3. The gear box according to claim 2, wherein: a thickness of the output gear is less than a height difference between the third plate and the fourth plate, and the thickness of the output gear is less than a distance between the fourth plate and the first surrounding plate; one of the first surrounding plate and the second surrounding plate has a convex part and the other has a concave part, the convex part cooperates with the concave part; first matching holes are arranged on the second surrounding plate located on both sides of the gap, second matching holes are arranged on the first surrounding plate opposite to the first matching holes, the first matching holes and the second matching holes are connected by first threaded fasteners; third matching holes are further arranged on the first surrounding plate or the first plate located on both sides of the transmission gear set, fourth matching holes are further arranged on the second surrounding plate or the third plate opposite to the third matching holes, and the third matching holes and the fourth matching holes are connected by second threaded fasteners.

4. The gear box according to claim 2, wherein: The transmission gear set comprises a worm, a worm wheel, a plurality of transmission gears and a plurality of shafts, the worm is circumferentially connected to the output shaft of the motor, the worm wheel is engaged with the worm, a plurality of the shafts are parallel to each other and are connected between the first housing and the second housing, each of the shafts is connected with one of the transmission gears or two circumferentially connected transmission gears, one of the transmission gears is connected with the worm wheel on the same shaft, and the other transmission gear is connected with the output gear on another shaft; the transmission gears on different shafts are sequentially engaged, starting from the transmission gear connected with the worm wheel and ending with the transmission gear connected with the output gear.

5. The gear box according to claim 4, characterized in that: at least one of the shafts is circumferentially connected with two transmission gears, the worm wheel and all the transmission gears are respectively aligned with one of the circumferentially connected transmission gears, the housing is arranged around the transmission gear set, and the output gear is arranged away from the circumferentially connected transmission gears; the first plate, the second plate, the third plate and the fourth plate are respectively provided with bosses and recesses in the bosses, the recesses of the first plate and the third plate are opposite to each other, the recesses of the second plate and the third plate are opposite to each other, and the two ends of the shaft are fixed in the corresponding recesses; the bosses of the first plate and the second plate are provided with reinforcing ribs, or the bosses of the third plate and the fourth plate are provided with reinforcing ribs.

6. The gear box according to claim 4, characterized in that: the transmission gears comprise a first gear, a second gear, a third gear, a fourth gear, a fifth gear, a sixth gear and a seventh gear, the shafts comprise a first shaft, a second shaft, a third shaft, a fourth shaft and a fifth shaft, the first gear and the worm wheel are circumferentially connected and arranged on the first shaft, the second gear and the third gear are circumferentially connected and arranged on the second shaft, the fourth gear and the fifth gear are circumferentially connected and arranged on the third shaft, the sixth gear is arranged on the fourth shaft, and the fifth gear and the output gear are circumferentially connected and arranged on the fifth shaft; the first gear is engaged with the second gear, the third gear is engaged with the fourth gear, the fifth gear is engaged with the sixth gear, and the sixth gear is engaged with the seventh gear.

7. The gear box according to claim 6, characterized in that: the worm wheel, the third gear and the fourth gear are aligned, and the first gear, the second gear, the fifth gear, the sixth gear and the seventh gear are aligned; the first gear is increased in tooth number or decreased in tooth number relative to the worm wheel, the third gear is increased in tooth number or decreased in tooth number relative to the second gear, the fifth gear is increased in tooth number or decreased in tooth number relative to the fourth gear, and the output gear is increased in tooth number or decreased in tooth number relative to the seventh gear. The first end of the accommodating cavity is opposite to the second end of the accommodating cavity; the first core shaft, the second core shaft, the third core shaft, the fourth core shaft and the fifth core shaft are distributed on both sides of the line from the first end of the accommodating cavity to the second end of the accommodating cavity.

8. A gearbox according to any one of claims 1 to 7, wherein: The motor is connected with the side surface of the shell, the thickness of the shell is less than the thickness of the motor, and the shell is provided with a convex block which is transitioned to the motor shell in a circular arc and is flush with the motor shell.

9. A gearbox according to claim 8, wherein: The motor is connected to the shell through a third threaded fastener.

10. A gearbox according to any one of claims 1 to 7, wherein: The shell is connected with a mounting plate, and the mounting plate is provided with a mounting hole.

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