CN113007287B

CN113007287B - Hollow gear set suspension gearbox with super multi-gear

Info

Publication number: CN113007287B
Application number: CN202110229952.0A
Authority: CN
Inventors: 李渝
Original assignee: Individual
Current assignee: Individual
Priority date: 2021-03-02
Filing date: 2021-03-02
Publication date: 2022-04-19
Anticipated expiration: 2041-03-02
Also published as: CN113007287A

Abstract

The invention relates to the technical field of gearboxes, in particular to a hollow gear set suspension gearbox with super-multi gears, which comprises a main transmission gear set, a fixed gear set, a first shaftless gear set and a second shaftless gear set, wherein the main transmission gear set rotates to drive a first free gear set of the first shaftless gear set to rotate, power transmission is realized through a slidable first gear shifting shaft, the first gear shifting shaft is arranged in the fixed shaft in a sliding mode, the fixed shaft is connected with the fixed gear set and drives the fixed gear set to rotate, the fixed gear set and a second free gear set of the second shaftless gear set are in meshing transmission, and the second gear shifting shaft is arranged in the center of the second free gear set in a sliding mode. The invention has compact structure and reasonable arrangement, can realize that the volume and weight change is not too large under the condition of changing 100 gears, has lower manufacturing cost, can simplify the processing and assembly and is convenient for the post-repair operation.

Description

Hollow gear set suspension gearbox with super multi-gear

Technical Field

The invention relates to the technical field of gearboxes, in particular to a hollow gear set suspension gearbox with super-multi gears.

Background

The manual gearbox mainly comprises gears and shafts, and the speed change and torque change are generated by combining different gears; the automatic gearbox AT consists of a hydraulic torque converter, a planetary gear, a hydraulic pitch-changing system and a hydraulic control system, and achieves speed and torque changing through a hydraulic transmission and gear combination mode.

The quality of the performance of the gearbox is the key for measuring the dynamic property, the economical efficiency and the drivability of the engineering machinery. The current speed change systems mainly comprise: mechanical transmission, hydraulic transmission, hydrostatic transmission. Nowadays, more and more engineering machines are applied to gearboxes, and requirements of large torque, large load and the like make speed changers of mechanical transmission increasingly popular. Along with the requirements of heavy load and large torque of engineering machinery, the structure of a transmission driven by the machinery is more complex, parts are numerous, the precision is high, the processing is difficult, the maintenance is complex, the disassembly is difficult, the occupied space is occupied, the operation is complex and the like.

Moreover, the existing mechanical transmission gearbox generally can realize few gear shifting gears, even if a large truck with excellent performance is used, the gear shifting gears are only between eight and sixteen, and the large truck and heavy engineering equipment adopt a gear transmission mode, so that the internal structure of the large truck and heavy engineering equipment is more complex, the parts are numerous, the installation precision requirement is high, the assembly is complicated, the processing cost is high, the size is larger, and the gear shifting gears are limited.

Disclosure of Invention

The invention aims to solve the technical problem of providing a hollow gear set suspension gearbox which can realize speed change of a plurality of gears, has compact and simple structure, smaller volume and lower cost and can simplify the processing, assembly and maintenance operation.

In order to achieve the purpose, the invention adopts the technical scheme that:

a hollow gear set suspension gearbox with super multi-gear comprises a main transmission gear set, a fixed gear set, a first shaftless gear set and a second shaftless gear set, wherein the main transmission gear set is fixed on an input shaft, the first shaftless gear set comprises a first free gear set, and the main transmission gear set is meshed with the first free gear set; a first gear shifting shaft capable of being clamped in a sliding manner is sleeved at the center of the first free gear set, a first clamp is arranged on the first gear shifting shaft, and the first clamp can be clamped and fixed with a gear of the first free gear set in the sliding process of the first gear shifting shaft; the fixed gear set is fixed on the fixed shaft, the first gear shifting shaft is slidably arranged on the inner wall of the fixed shaft, the second shaftless gear set comprises a second free gear set, and the fixed gear set and the second free gear set are in meshed connection; the central point of second free gear set puts the cover and is equipped with the second gear shifting shaft that can slide the joint, be provided with the second checkpost on the second gear shifting shaft, the second gear shifting shaft can be fixed with the gear joint of second free gear set at gliding in-process second checkpost.

Optionally, the gear arrangement on the fixed gear set is arranged in a stepped manner according to the diameter, and the gear with the smallest diameter on the fixed gear set is meshed with a free gear with a certain large diameter on the second free gear set through an intermediate gear; the second shift shaft is connected to the output shaft.

Optionally, the first shaftless gear set further includes a first movable gear set, the first movable gear set includes a plurality of movable gears and a first steel sleeve, the plurality of movable gears are arranged in a stepped manner and symmetrically arranged on two sides of the first steel sleeve, the movable gears on two sides of the first steel sleeve and the driving transmission gear of the driving transmission gear set are distributed in a regular triangle and are respectively meshed with the free gear of the first free gear set, so as to fix the position of the first free gear set; the second shaftless gear train still includes second movable gear group, second movable gear group includes that a plurality of moves gear and second steel bushing, a plurality of the movable gear be cascaded arrangement, symmetrical setting on the both sides of second steel bushing, thereby the movable gear on second steel bushing both sides and the gear of fixed gear train are the position of the fixed second free gear train of the free gear meshing of second free gear train respectively and the distribution of falling triangle-shaped.

Optionally, a first shift lever is fixed to the first shift shaft, and a second shift lever is fixed to the second shift shaft.

Optionally, a first positioning block is arranged on the inner side of the free gear on the first free gear set, and the first clip of the first shift shaft is arranged to be tightly attached to the first positioning block and the inner wall of the free gear; a second positioning block protruding from the inner side of the free gear on the second free gear set is arranged, and a second clip of the second gear shifting shaft is arranged in a manner of clinging to the second positioning block and the inner wall of the free gear; the clearance between every two free gears is neutral position entering point, and when first checkpost or second checkpost entered this position be neutral gear, it is the gearshift to enter into free gear inside as first checkpost or second checkpost.

Optionally, the first clip and the second clip are retractable clips.

Optionally, the first clip and the second clip are provided with contact sensors, and a stopper is provided on a side surface of each free gear of the first free gear set and the second free gear set.

Optionally, the second steel bushing includes a gear seat and a limiting plate, a plurality of gear seats are symmetrically arranged on two sides of the second steel bushing in a step-wise increasing manner, a distance between each two symmetrical gear seats on two sides of the second steel bushing is determined according to a diameter of the matched free gear, and a moving gear is rotatably arranged in each gear seat; every two the gear seat between still be provided with the limiting plate of extension, the both sides of each free gear of first free gear group and second free gear group are provided with bellied smooth surface.

Optionally, the fixed shaft is fixed on the fixed gear set, the fixed shaft is a hollow shaft, a groove is formed in the inner side of the fixed shaft, a fixed boss surface is arranged on the first gear shifting shaft, and the fixed boss surface is slidably arranged in the groove of the fixed shaft.

The invention has the following advantages and beneficial effects:

1. the transmission device drives the first free gear set of the first shaftless gear set to rotate through the rotation of the main transmission gear set, and realizes the transmission of power through the slidable first gear shifting shaft, and the first gear shifting shaft realizes the connection of the free gear and the placement of the free gear into a neutral gear through the first clamp; the first gear shifting shaft is arranged in the fixed shaft in a sliding mode, the first gear shifting shaft and the fixed shaft synchronously rotate, the fixed shaft drives the fixed gear set to rotate, the fixed gear set and the second free gear set of the second shaftless gear set are in meshing transmission, and finally the connection and torque transmission of the gears of the second free gear set and the second gear shifting shaft are achieved through the sliding of the second gear shifting shaft. The invention realizes the operation of gear shifting by connecting the free gear sets of the two shaftless gear sets through the two gear shifting shafts, can simply realize the replacement of 4X 8-32 gears, comprises 4 reverse gears, can meet the speed change in the fields of almost any large-scale engineering machinery, civil appliances and the like, is not limited to the change of 32 gears, can set more gears only by adding a certain number of gears, and can realize the change of more gears of gear shifting.

2. According to the invention, on the aspect of overall spatial arrangement, only upper and lower layers of spatial arrangement are arranged, and each group of gears are arranged in a stepped symmetrical meshing manner, so that in the process of gear shifting, the gear shifting can be conveniently realized only by moving the gear shifting shaft, and compared with the existing gear shifting structure, the gear shifting structure has no problems of complex gear arrangement and few gear shifting gears. The driving transmission gear set, the first shaftless gear set, the fixed gear set and the second shaftless gear set are arranged on a horizontal line in a gathering mode, and the internal structure is compact and simple, reasonable in arrangement and easy to assemble and disassemble; the transmission only comprises four gear sets, so that the internal complexity of the transmission is greatly reduced, more precise, complex and various gears are not required to be arranged in a matching way, the components are simplified, the occupied space is smaller, and the volume and weight change is not too large under the condition of realizing the shift of 32 x 2 gears.

3. According to the invention, the moving gear of the shaftless gear set is fixed by designing the steel sleeve, and the position of the free gear is fixed by meshing the moving gear and the free gear; furthermore, limiting plates extend out of two sides of the gear seat of the steel sleeve, so that a fixed point is formed by the limiting plates and the smooth surface of the free gear, and the free gear can be fixed in position in the whole space, so that the transmission stability of the free gear is guaranteed, and the overall performance is further guaranteed.

4. The invention realizes the connection and the separation of the shift shaft and the free gear through the slide of the first shift shaft and the second shift shaft and the clamp, thereby realizing the operation of shifting and putting into the neutral position.

Drawings

FIG. 1 is a front view of a hollow gearset suspension gearbox with ultra-multi-speed ratios according to an embodiment of the present invention;

FIG. 2 is a schematic view of the meshing engagement of the drive gear set and the first shaftless gear set taken along the direction A-A in FIG. 1;

FIG. 3 is a schematic view of the moving gear set of FIG. 2 disposed in a first steel sleeve;

FIG. 4 is a schematic illustration of the engagement of the fixed gear set and the second shaftless gear set in the direction B-B of FIG. 1;

FIG. 5 is a side view of one of the sets of moving gears of FIG. 4;

FIG. 6 is a schematic view of the moving gear set of FIG. 4 disposed in a second steel sleeve;

FIG. 7 is a meshing schematic view of the second shaftless gear set in the top view of FIG. 4;

FIG. 8 is a cross-sectional view taken along the line C-C in FIG. 7;

FIG. 9 is a schematic view of a first shift shaft within the first free gear set;

FIG. 10 is a cross-sectional view taken along line D-D of FIG. 9;

FIG. 11 is a cross-sectional view taken along the line E-E in FIG. 9;

FIG. 12 is a schematic view of the first shift shaft being sleeved on the stationary shaft;

FIG. 13 is a cross-sectional view taken along the direction F-F in FIG. 12;

icon: 1-input shaft, 11-main drive gear set, 2-first shift shaft, 21-first catch, 22-fixed boss face, 23-first shift lever, 23-first shaftless gear set, 231-first free gear set, 232-first movable gear set, 2311-first positioning block, 24-first steel sleeve, 3-first fixed seat, 4-fixed shaft, 41-fixed gear set, 5-second fixed seat, 6-third fixed seat, 7-central shaft, 71-intermediate gear, 8-second shift shaft, 81-second catch, 82-second shift lever, 83-second shaftless gear set, 831-second free gear set, 8311-second positioning block, 8312-smooth surface, 8313-gear engaging point, 8314-a neutral position insertion point, 832-a second moving gear set, 84-a second steel sleeve, 841-a gear seat, 842-a limiting plate and 9-a positioning shaft.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention.

Thus, the following detailed description of the embodiments of the present invention, presented in the figures, is not intended to limit the scope of the invention, as claimed, but is merely representative of selected embodiments of the invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Examples

As shown in fig. 1, fig. 2 and fig. 4, the hollow gear set suspension gearbox with super-multiple gears comprises a main transmission gear set 11, a fixed gear set 41, a first shaftless gear set 23 and a second shaftless gear set 83, wherein the main transmission gear set 11 comprises a plurality of main transmission gears (four main transmission gears with different diameters are arranged in the scheme) with different diameters, the main transmission gear set 11 is fixed on an input shaft 1, and one end of the input shaft 1 is rotatably arranged on a first fixed seat 3.

The first shaftless gear group 23 comprises a first free gear group 231 and a first moving gear group 232, the first free gear group 231 comprises a plurality of free gears with different diameters (in the scheme, the first free gear group 231 is provided with four free gears with different diameters), the number of the gears of the main transmission gear group 11 and the first free gear group 231 is equal, and two gears are meshed with each other to be connected for transmission; the first moving gear set 232 comprises a plurality of moving gears and a first steel sleeve 24, the moving gears are arranged in a stepped mode and symmetrically arranged on two sides of the steel sleeve, the moving gears 2321 on two sides of the first steel sleeve 24 and the driving transmission gears of the driving transmission gear set 11 are distributed in a regular triangle shape and are respectively meshed with the free gears of the first free gear set 231, and therefore the position of the first free gear set 231 is fixed.

The first free gear set 231 is sleeved with a slidable first shift shaft 2 at a central position thereof, the first shift shaft 2 is provided with a first hook 21, and the first hook 21 can be engaged and fixed with the free gear of the first free gear set 231 during the sliding of the first shift shaft 2.

The first shift shaft 2 is slidably disposed on an inner wall of the fixed shaft 4, the fixed shaft 4 is fixed with a fixed gear set 41, and both ends of the fixed shaft 4 are rotatably disposed on the second fixed seat 5 and the third fixed seat 6, respectively. The second shaftless gear group 83 comprises a second free gear group 831 and a second gear group 832, the second free gear group 831 comprises a plurality of free gears, the number of the gears of the fixed gear group 41 and the second free gear group 831 is equal (the number of the free gears of the second free gear group 831 is 8 in the invention) and two of the free gears are meshed and connected for transmission; the second movable gear set 832 comprises a plurality of movable gears and a second steel sleeve 84, the movable gears are arranged in a stepped mode and symmetrically arranged on two sides of the second steel sleeve 84, the movable gears on two sides of the second steel sleeve 84 and the gears of the fixed gear set 41 are distributed in an inverted triangle mode and are respectively meshed with the free gears of the second free gear set 831, and therefore the position of the second free gear set 831 is fixed.

The second free gear set 831 is provided with a slidable second shift shaft 8 at a central position thereof, the second shift shaft 8 is provided with a second hook 81, and the second hook 81 can be engaged and fixed with the gear of the second free gear set 831 during the sliding of the second shift shaft 8. Wherein, the free gear with the smallest diameter of the fixed gear set 41 is engaged with the free gear of the second free gear set 831 through the intermediate gear 71, which is a reverse gear; the intermediate gear 71 is fixed on the second fixed seat 5 and the third fixed seat 6 through the central shaft 7; one end of the second shift shaft 8 is sleeved on the positioning shaft 9, and the other end of the second shift shaft 8 is connected to the output shaft.

The invention drives the first free gear set 231 of the first shaftless gear set 23 to rotate through the rotation of the main transmission gear set 11, and realizes the transmission of power through the slidable first gear shift shaft 2, and the first gear shift shaft 2 realizes the connection of free gears and the arrangement of the free gears into a neutral gear through the first clamp 21; the first shift shaft 2 is slidably disposed inside the fixed shaft 4, and the fixed shaft 4 rotate synchronously, the fixed shaft 4 drives the fixed gear set 41 to rotate, the fixed gear set 41 and the second free gear set 831 of the second shaftless gear set 83 are in mesh transmission, and finally, the connection transmission torque of the gears of the second free gear set 831 and the second shift shaft 8 is realized through the sliding of the second shift shaft 8. The invention realizes the operation of gear shifting by connecting the free gear sets of the two shaftless gear sets through the two gear shifting shafts, can simply realize the replacement of 4 × 8-32 gears, comprises 4 reverse gears, can meet the speed change in the fields of almost any large engineering machinery, civil machinery and the like, is not limited to the change of 32 gears, can set more gears only by adding a certain number of gears, and can realize the change of more gears of gear shifting.

In addition, the gear sets are arranged compactly, the gears of each set are arranged in a stepped manner, multi-gear speed change is realized by combining a plurality of sets of simple gears and clamping the first gear shifting shaft 2 and the second gear shifting shaft 8, the structure is simple and compact, the space is not occupied, the assembly is easy, the number of the needed gears is less, the internal structure is simpler, the requirements on the processing precision and the assembly precision are further reduced, and the economy is high. Compared with the gear shifting mode in the prior art, the gear shifting mode can realize the shifting of more gears with more compact gear combinations, and the volume and weight change is not too large under the condition of realizing 32 gear shifting.

The first shift lever 23 is fixed to the first shift shaft 2, and the second shift lever 82 is fixed to the second shift shaft 8. The gear shifting deflector rod is externally connected with the gear of the console, and can artificially control the gear shifting so as to meet the requirement of manual gear shifting and meet the artificial operation feeling; furthermore, the first shift lever 23 and the second shift lever 82 may be externally connected to a microcomputer controlled automatic transmission system, so that the automatic transmission system becomes an AMT transmission, and the operation is more intelligent and convenient compared with a manual transmission.

As shown in fig. 2 and 4, further, a raised first stopper 2311 is provided on the center hole of the free gear of the first free gear set 231, and the first catch 21 of the first shift spindle 2 is disposed closely to the first stopper 2311 and the center hole surface of the free gear; a second positioning block 8311 is also provided on the inner side of the free gear of the second free gear group 831, and the second catch 81 of the second shift spindle 8 is disposed in close contact with the second positioning block 8311 and the central hole surface of the free gear. As shown in fig. 8, the gap between each two free gears is a neutral position insertion point 8314, which is a neutral position when the first hook 21 or the second hook 81 is brought into this position; the play between each free gear and the first or

second shift shaft

2, 8 is a shift input point 8313, which can be fixedly connected to the free gear when the first or

second catch

21, 81 is brought into this position, and the shift is successful. The gear shifting mode is easy to operate, the space for arranging the gears is also saved, the gears can be arranged more compactly, and the gears can be changed in more gears in a smaller volume.

The present invention realizes a gear engaging operation by engaging and disengaging the first and

second shift shafts

2 and 8 with and from the first and second free gear sets 231 and 831, respectively, and can realize connection fixation and disengagement by the first and

second clips

21 and 81 well. The combination of the two shift shafts can realize the transformation of more than a plurality of gears, and the gear-shifting mechanism is very suitable for various large-scale instruments.

Further, the first clip 21 and the second clip 81 are configured as retractable clips. In the present invention, the center surface of the free gear is provided with the first positioning block 2311 and the second positioning block 8311 which are protruded instead of the concave notches, so that when the first clip 21, the second clip 81 and the free gear are connected, the first clip 21 and the second clip 81 can be more quickly and easily butted, thereby realizing quick gear shifting. However, in order to further enhance the speed of shifting and the smooth and smooth gear shifting without jerk, the first and

second clips

21 and 81 are provided as retractable clips so that the clips can directly reach the designated positions without adjusting the search entry point when the first and

second shift shafts

2 and 8 are moved, and then the first or

second clips

21 or 81 extend and snap-engage with the free gear to realize shifting.

Further, the first clip 21 and the second clip 81 are provided with a touch sensor, and a stopper is provided on a side surface of the free gear. In order to ensure that the telescopic clip has a sufficiently rapid response, the first clip 21 and the second clip 81 are under the condition of extension under normal conditions, and springs are arranged inside the clips; when the first gear shift shaft 2 is moved to shift gears and the clips contact with the gear piece of the free gear, the contact type sensor transmits signals, and the first clips 21 are automatically compressed at the moment, so that the first clips enter the free gear smoothly; when the whole clip enters the free gear, the signal of the contact sensor disappears, and the clip is restored to the original position by the elasticity of the internal spring, so that the first gear shift shaft 2 is connected with the free gear in a buckling manner. Due to the design, the first gear shifting shaft 2 or the second gear shifting shaft 8 can quickly react and complete gear shifting operation, the blocking and jerking feeling in the gear shifting process is reduced, the gear shifting operation can be reliably realized, and the integral stability of the transmission is further ensured.

As shown in fig. 3, 5, 6 and 7, the second steel sleeve 84 includes a gear seat 841 and a limiting plate 842, a plurality of gear seats 841 are symmetrically and gradually arranged on two sides of the second steel sleeve 84, the distance between every two symmetrical gear seats 841 on two sides of the second steel sleeve 84 is determined according to the diameter of the matched free gear, and a moving gear is rotatably arranged in the gear seat 841; an extended limiting plate 842 is further arranged between every two gear seats 841, two sides of each free gear of the free gear set are provided with raised smooth surfaces 8312, and the first steel sleeve 24 is designed as the second steel sleeve 84. First, in the present invention, the first free gear set 231 is engaged and fixed in position by the first moving gear set 232 and the driving transmission gear set 11; the second free gear set 831 is meshed with and fixed to the fixed gear set 41 via the second movable gear set 832. Secondly, the design of the steel sleeve can be very compact and stable, and the mounting positions of the moving gears can be symmetrically arranged to be meshed and connected with the free gear; not only does so, the steel bushing is as the part of fixed moving gear, and it still is provided with limiting plate 842, and limiting plate 842 can be injectd the smooth surface 8312 of free gear in each position, prevents that its drunkenness, the off tracking that takes place the position in the process of moving from influencing the transmission effect to further guaranteed the stability of derailleur, through the steel bushing with each gear set design again, make the holistic space of derailleur more compact.

As shown in fig. 1, 9, 10, 11, 12 and 13, the fixed shaft 4 is fixed to the fixed gear set 41, wherein the fixed shaft 4 is a hollow shaft, a groove is provided on the inner side of the fixed shaft 4, and the first shift shaft 2 is provided with a fixed boss surface 22, and the fixed boss surface 22 is slidably provided in the groove of the fixed shaft 4, so that the first shift shaft 2 can slide on the fixed shaft 4 and can drive the fixed shaft 4 to move synchronously.

The working principle is as follows:

firstly, the input shaft 1 drives the driving transmission gear set 11 to rotate, the driving transmission gear set 11 drives the first free gear set 231 meshed with the driving transmission gear set to rotate, and the first free gear set 231 is fixed in position through the meshing of the first free gear set 232 and the driving transmission gear set 11; the first shift lever 23 is shifted to slide the first shift shaft 2 in the inner center hole of the first free gear set 11, and when the first hook 21 slides into the corresponding free gear, a snap connection is formed, so that the first shift shaft 2 rotates and drives the fixed shaft 4 to rotate, and when the first hook 21 is located between two free gears, the first free gear set 231 idles, and is in a neutral position at this time, the first shift shaft 2 can slide to any one of the free gears to complete a shift, so that one of the free gears of the first free gear set 231 drives the first shift shaft 2 to rotate, so that the first shift shaft 2 rotates and drives the fixed shaft 4 to rotate.

The fixed gear set 41 drives the second free gear set 831 engaged therewith to rotate, and the second free gear set 831 is fixed in position by the engagement of the second gear set 832 and the fixed gear set 41. Shifting the second shift lever 82 causes the second shift shaft 8 to slide in the inner center hole of the second freewheel group 831, which transmits power to the second shift shaft 8 while the second catch 81 slides inside the corresponding freewheel to form a snap-fit connection. Similarly, the second hook 81 can slide freely in the second free gear group 831 to be connected and fixed to a desired free gear, thereby completing final torque output.

The above is only a preferred embodiment of the present invention, and is not intended to limit the present invention, and various modifications and changes will occur to those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. The utility model provides a hollow gear train suspension gearbox of super many grades of gears which characterized in that:

the driving gear set is characterized by comprising a driving transmission gear set (11), a fixed gear set (41), a first shaftless gear set (23) and a second shaftless gear set (83), wherein the driving transmission gear set (11) is fixed on an input shaft (1), the first shaftless gear set (23) comprises a first free gear set (231), and the driving transmission gear set (11) is meshed with the first free gear set (231);

the center of the first free gear set (231) is sleeved with a first gear shifting shaft (2) capable of being clamped in a sliding mode, a first clamp (21) is arranged on the first gear shifting shaft (2), and the first clamp (21) can be clamped and fixed with a gear of the first free gear set (231) in the sliding process of the first gear shifting shaft (2);

the fixed gear set (41) is fixed on the fixed shaft (4), the first gear shift shaft (2) is slidably arranged on the inner wall of the fixed shaft (4), the second shaftless gear set (83) comprises a second free gear set (831), and the fixed gear set (41) and the second free gear set (831) are meshed and connected;

a second gear shifting shaft (8) capable of being clamped in a sliding mode is sleeved at the center position of the second free gear set (831), a second clamp (81) is arranged on the second gear shifting shaft (8), and the second clamp (81) can be clamped and fixed with a gear of the second free gear set (831) in the sliding process of the second gear shifting shaft (8);

the first shaftless gear set (23) further comprises a first movable gear set (232), the first movable gear set (232) comprises a plurality of movable gears and a first steel sleeve (24), the plurality of movable gears are arranged in a stepped mode and symmetrically arranged on two sides of the first steel sleeve (24), and the movable gears (232) and the driving transmission gear set (11) on two sides of the first steel sleeve (24) are distributed in a regular triangle mode and are respectively meshed with free gears of the first free gear set (231) so as to fix the position of the first free gear set (231);

the second shaftless gear set (83) further comprises a second movable gear set (832), the second movable gear set (832) comprises a plurality of movable gears and a second steel sleeve (84), the movable gears are arranged in a stepped mode and symmetrically arranged on two sides of the second steel sleeve (84), and the movable gears (832) and the fixed gear set (41) on two sides of the second steel sleeve (84) are distributed in an inverted triangle mode and are meshed with free gears of the second free gear set (831) respectively so as to fix the position of the second free gear set (831).

2. The hollow gearset suspended gearbox of claim 1, characterised in that: the gear arrangement on the fixed gear set (41) is in stepped arrangement according to the diameter, and a gear with the minimum diameter on the fixed gear set (41) is meshed with a free gear with a large diameter of the second free gear set (831) through an intermediate gear (71); the second shift shaft (8) is connected to the output shaft.

3. The hollow gearset suspended gearbox of claim 1, characterised in that: a first gear shifting lever (23) is fixed on the first gear shifting shaft (2), and a second gear shifting lever (82) is fixed on the second gear shifting shaft (8).

4. The hollow gearset suspended gearbox of claim 1, characterised in that: a first raised locating block (2311) is arranged on the inner side of a free gear on the first free gear set (231), and a first clamp (21) of the first gear shifting shaft (2) is arranged in a manner of clinging to the first locating block (2311) and the inner wall of the free gear; a second positioning block (8311) is arranged at the inner side of the free gear on the second free gear set (831), and a second clip (81) of the second gear shifting shaft (8) is arranged in a manner of clinging to the second positioning block (8311) and the inner wall of the free gear; the gap between every two free gears is a neutral position insertion point (8314).

5. The hollow gearset suspended gearbox of claim 1, characterised in that: the first clip (21) and the second clip (81) are arranged to be telescopic.

6. The hollow gearset suspended gearbox of claim 5, characterised in that: contact sensors are arranged on the first clip (21) and the second clip (81), and a baffle is arranged on the side surface of each free gear of the first free gear set (231) and the second free gear set (831).

7. The hollow gearset suspended gearbox of claim 1, characterised in that: the second steel sleeve (84) comprises a gear seat (841) and a limiting plate (842), a plurality of gear seats (841) are symmetrically and gradually arranged on two sides of the second steel sleeve (84) in a stepped manner, and a moving gear is rotatably arranged in each gear seat (841); an extended limiting plate (842) is further arranged between every two adjacent gear seats (841), and two sides of each free gear of the first free gear set (231) and the second free gear set (831) are provided with raised smooth surfaces (8312).

8. The hollow gearset suspended gearbox of claim 1, characterised in that: the fixed shaft (4) is fixed on the fixed gear set (41), the fixed shaft (4) is a hollow shaft, a groove is formed in the inner side of the fixed shaft (4), a fixed boss surface (22) is arranged on the first gear shifting shaft (2), and the fixed boss surface (22) is arranged in the groove of the fixed shaft (4) in a sliding mode.