CN216867430U

CN216867430U - Four-wheel drive mini-tiller belt transmission case

Info

Publication number: CN216867430U
Application number: CN202220404273.2U
Authority: CN
Inventors: 王杰荣
Original assignee: Liuzhou Xinsheng Agricultural Machinery Co ltd
Current assignee: Liuzhou Xinsheng Agricultural Machinery Co ltd
Priority date: 2022-02-28
Filing date: 2022-02-28
Publication date: 2022-07-01
Anticipated expiration: 2032-02-28

Abstract

The utility model relates to the technical field of agricultural machinery, in particular to a belt transmission case of a four-wheel-drive mini-tiller, which comprises a main transmission case and a rotary tillage case connected with the main transmission case, wherein the main transmission case comprises a transmission case body, a first transmission shaft, a second transmission shaft, a reverse gear shaft, a third transmission shaft and a fourth transmission shaft, a rotary tillage driving gear is arranged on the second transmission shaft, a rotary tillage driven gear is arranged on the third transmission shaft, the rotary tillage driven gear is rotatably supported at the upper end of the third transmission shaft, and the rotary tillage driven gear can be meshed with the rotary tillage driving gear. In the four-wheel-drive mini-tiller belt transmission case, the transmission and disconnection of the walking power and the rotary tillage power are respectively and independently controlled, the output of the rotary tillage power is not influenced no matter the mini-tiller walks forwards or backwards, the mini-tiller walking and tillage operation are mutually independent and do not interfere with each other.

Description

Four-wheel drive mini-tiller belt transmission case

Technical Field

The utility model relates to the technical field of agricultural machinery, in particular to a belt transmission case of a four-wheel-drive mini-tiller.

Background

The mini-tiller is powered by a small diesel engine or a gasoline engine, has the characteristics of light weight, small size and the like, is widely suitable for dry lands, paddy fields, orchards and the like in plains, mountainous areas and hills, can be used for pumping water, generating electricity, spraying medicine, spraying and the like by being matched with corresponding machines, can be freely driven in the fields, is convenient for users to use and store, saves the trouble that large agricultural machinery cannot enter the fields in the mountainous areas, is the best choice for vast farmers to replace cattle tillage, has the influence of advancing and shifting gear of the mini-tiller on the rotary tillage power output, and has a complex structure of a transmission case of the mini-tiller, and is inconvenient for the users to use.

SUMMERY OF THE UTILITY MODEL

The utility model aims to solve the problems and provide a belt transmission case of a four-wheel-drive mini-tiller.

In order to achieve the purpose, the utility model adopts the technical scheme that: a belt transmission case of a four-wheel-drive mini-tiller comprises a main transmission case and a rotary tillage case connected with the main transmission case, wherein the main transmission case comprises a transmission case body, a transmission primary shaft, a transmission secondary shaft, a reverse shaft, a transmission three shaft and a transmission four shaft, a primary shaft transmission gear is arranged on the transmission primary shaft, one end of the transmission primary shaft extends out of the transmission case body and is matched with a belt transmission type external clutch, a secondary shaft transmission gear and a rotary tillage driving gear are arranged on the transmission secondary shaft, the secondary shaft transmission gear is meshed with a primary shaft transmission gear, the rotary tillage driving gear can move along the axial direction of the transmission secondary shaft, a reverse gear duplicate gear is arranged on the reverse shaft, a pinion of the reverse gear duplicate gear is meshed with the secondary shaft transmission gear, a three-shaft transmission gear and a driven gear are arranged on the transmission three shaft, the peripheral side surface of the upper end of the transmission three shaft is a smooth cylindrical surface, a spline is arranged on the peripheral side surface of the lower end of the transmission three shaft, and the three shaft transmission gear is connected with the lower end of the transmission shaft by the spline in a sliding way, the three-shaft transmission gear can be meshed with the two-shaft transmission gear or meshed with a large gear of a reverse gear duplicate gear on the reverse gear shaft, the rotary tillage driven gear is rotatably supported at the upper end of the transmission three shaft, the rotary tillage driven gear is a duplicate gear, and the large gear of the rotary tillage driven gear can be meshed with the rotary tillage driving gear; four-axis drive gears and four-axis transition gears are arranged on the four drive shafts, the thickness of each four-axis drive gear is two times larger than that of each three-axis drive gear, and the four-axis drive gears are meshed with the three-axis drive gears.

Preferably, the main transmission box further comprises a five transmission shafts and a six transmission shafts, five-shaft transmission gears and high-low gear driving gears are arranged on the five transmission shafts, the high-low gear driving gears are duplicate gears, the high-low gear driving gears can axially move along the five transmission shafts, the five-shaft transmission gears are meshed with the four-shaft transition gear, six transmission gears, a high-gear driven gear and a low-gear driven gear are arranged on the six transmission shafts, large gears of the high-low gear driving gears can be meshed with the high-gear driven gear to form a high gear, and small gears of the high-low gear driving gears can be meshed with the low-gear driven gear to form a low gear.

Preferably, the main transmission case also comprises a seven transmission shafts, a driving gear is arranged in the middle of the seven transmission shafts, the driving gear is meshed with the six transmission gears, and two ends of the seven transmission shafts are used for installing driving wheels.

Preferably, the main transmission case still includes eight transmission shafts and nine transmission shafts, eight transmission gears and eight transition gears are arranged on the eight transmission shafts, the eight transmission gears are engaged with the pinion of the rotary tillage driven gear, nine transmission gears and nine transmission chain wheels are arranged on the nine transmission shafts, the nine transmission gears are engaged with the eight transition gears, the rotary tillage case includes a rotary tillage case body and a rotary tillage shaft, the rotary tillage case body is obliquely connected to the right side of the transmission case body, a rotary tillage chain wheel is arranged on the rotary tillage shaft, and a chain is sleeved on the rotary tillage chain wheel and the nine transmission chain wheels.

Preferably, the transmission primary shaft, the transmission secondary shaft, the transmission four-shaft and the transmission five-shaft, the six-shaft transmission gear, the eight-shaft transmission gear and the nine-shaft transmission gear are spline shafts, the one-shaft transmission gear is statically connected with the one-shaft transmission shaft through a spline, the two-shaft transmission gear is statically connected with the two-shaft transmission shaft through a spline, a rotary tillage driving gear is slidingly connected with the two-shaft transmission shaft through a spline, a rotary tillage driving gear is connected with a shifting fork, the four-shaft transmission gear and the four-shaft transition gear are statically connected with the four-shaft transmission shaft through a spline, the five-shaft transmission gear is statically connected with the five-shaft transmission shaft through a spline, the high-low gear driving gear is slidingly connected with the five-shaft transmission shaft through a spline, the six-shaft transmission gear, the high-gear driven gear and the low-gear driven gear are statically connected with the six-shaft transmission shaft through a spline, the eight-shaft transmission gear and the eight-shaft transition gear are statically connected with the eight transmission shaft through a spline, and the nine-shaft transmission gear and the nine transmission chain wheel are statically connected with the nine transmission shaft through a spline.

Preferably, the inner ring of the reverse double gear is rotatably supported on the reverse shaft through a copper sleeve, and the reverse double gear is axially positioned through a retainer ring.

Preferably, the inner ring of the rotary tillage driven gear is rotatably supported at the upper end of the three transmission shafts through a copper sleeve, and the rotary tillage driven gear is axially positioned through a retaining ring.

In the belt transmission case of the four-wheel-drive mini-tiller, the transmission and disconnection of the walking power and the rotary tillage power are respectively and independently controlled, the output of the rotary tillage power is not influenced no matter the mini-tiller walks forwards or backwards, and the mini-tiller walks independently and does not interfere with tillage operation. In addition, the belt transmission case of the four-wheel-drive mini-tiller realizes quick switching of forward or backward walking of the mini-tiller, has a simple and light overall structure, and is convenient for a user to control the mini-tiller to move forward or backward.

Drawings

The utility model is further illustrated with reference to the following figures and examples.

FIG. 1 is a schematic structural diagram of a four-wheel-drive mini-tiller belt transmission case provided by a preferred embodiment of the utility model;

FIG. 2 is a cross-sectional view taken along line A-A of FIG. 1;

FIG. 3 is a cross-sectional view taken along line B-B of the reverse shaft and a reverse double gear disposed on the reverse shaft of FIG. 1;

in the figure: 1. a transmission case body; 11. a drive shaft; 112. a shaft transmission gear; 12. a transmission secondary shaft; 121. a two-axis transmission gear; 122. a rotary tillage driving gear; 13. three shafts are driven; 131. a three-axis drive gear; 132. a driven gear is rotary-ploughed; 14. a transmission four-axis; 141. a four-axis transmission gear; 142. a four-axis transition gear; 15. five shafts are driven; 151. a five-axis transmission gear; 152. a high-low gear driving gear; 16. six shafts are driven; 161. a six-shaft transmission gear; 162. a high-gear driven gear; 163. a low-gear driven gear; 17. a transmission seven shaft; 171. a drive gear; 18. eight shafts are driven; 181. eight-shaft transmission gears; 182. an eight-axis transition gear; 19. nine shafts are driven; 191. a nine-shaft transmission gear; 192. a nine-shaft drive sprocket; 10. a reverse gear shaft; 101. a reverse double gear; 2. a rotary tillage box body; 21. a rotary tillage shaft; 22. a rotary tillage chain wheel; 23. a chain; 3. belt drive type external clutch.

Detailed Description

The utility model will now be described in further detail with reference to the accompanying drawings and examples, which are simplified schematic drawings and illustrate only the basic structure of the utility model in a schematic manner, and thus show only the constituents relevant to the utility model.

In the description of the present invention, it is to be understood that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", and the like, indicate orientations or positional relationships based on those shown in the drawings, and are used only for convenience in describing the present invention and for simplicity in description, and do not indicate or imply that the referenced devices or elements must have a particular orientation, be constructed and operated in a particular orientation, and thus, are not to be construed as limiting the present invention. Furthermore, the terms "first," "second," and the like are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or to implicitly indicate a number of the indicated technical features. Thus, a feature defined as "first," "second," etc. may explicitly or implicitly include one or more of that feature. In the description of the present invention, "a plurality" means two or more unless otherwise specified.

In the description of the present invention, it should be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, e.g., as meaning either a fixed connection, a removable connection, or an integral connection; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meaning of the above terms in the present invention can be understood by those of ordinary skill in the art through specific situations.

As shown in fig. 1, 2 and 3, a belt transmission case of a four-wheel-drive mini-tiller according to a preferred embodiment of the present invention includes a main transmission case and a rotary tillage case connected to the main transmission case.

The main transmission case comprises a transmission case body 1, a first transmission shaft 11, a second transmission shaft 12, a reverse gear shaft 10, a third transmission shaft 13, a fourth transmission shaft 14, a fifth transmission shaft 15, a sixth transmission shaft 16, a seventh transmission shaft 17, an eighth transmission shaft 18 and a ninth transmission shaft 19, wherein shaft necks at two ends of each shaft are respectively provided with a bearing fixed on the transmission case body 1.

The transmission case body 1 is integrally formed by stamping, and the integrally formed case body is compared with a case body formed by splicing a plurality of small casting case bodies, so that the manufacturing cost is low, the assembly difficulty is small, the weight of the case body is moderate, and the requirements of farmers on low price, light weight and stable operation of the mini-tiller are met.

The transmission shaft 11 is provided with a shaft transmission gear 112, the transmission shaft 11 is a spline shaft, the shaft transmission gear 112 is statically connected with the transmission shaft 11 through a spline, the shaft transmission gear 112 and the transmission shaft 11 synchronously rotate, one end of the transmission shaft 11 extends out of the transmission box body 1 and is matched with the belt transmission type external clutch 3, and power output by the engine is transmitted to the transmission shaft 11 or power transmitted to the transmission shaft 11 is cut off through the belt transmission type external clutch 3. The belt-driven external clutch 3 includes a clutch pulley and a belt drive device which are assembled between the driving shaft 11 and the engine, and the belt-driven external clutch 3 is the most common clutch, belongs to the prior art, and is not described in detail.

The transmission secondary shaft 12 is provided with a secondary transmission gear 121 and a rotary tillage driving gear 122, the diameter of the secondary transmission gear 121 is equal to that of the rotary tillage driving gear 122 (in fig. 1, the secondary transmission gear 121 is overlapped with the rotary tillage driving gear 122), the transmission secondary shaft 12 is a spline shaft, the secondary transmission gear 121 is statically connected with the transmission secondary shaft 12 through a spline, so that the secondary transmission gear 121 and the transmission secondary shaft 12 synchronously rotate, and the secondary transmission gear 121 is meshed with the primary transmission gear 112. The rotary tillage driving gear 122 is connected with the transmission shaft 12 in a sliding mode through splines, the rotary tillage driving gear 122 is connected with a shifting fork, and the rotary tillage driving gear 122 can move axially along the transmission shaft 12 under the control of the shifting fork.

The reverse gear shaft 10 is provided with a reverse gear duplicate gear 101, the reverse gear duplicate gear 101 is rotatably supported on the reverse gear shaft 10, specifically, an inner ring of the reverse gear duplicate gear 101 is rotatably supported on the reverse gear shaft 10 through a copper bush (not shown), the reverse gear duplicate gear 101 is axially positioned through a retainer ring (not shown), and a pinion of the reverse gear duplicate gear 101 is meshed with the two-shaft transmission gear 121.

A three-shaft transmission gear 131 and a rotary tillage driven gear 132 are arranged on the transmission three shaft 13, the peripheral side surface of the upper end of the transmission three shaft 13 is a smooth cylindrical surface, a spline is arranged on the peripheral side surface of the lower end of the transmission three shaft 13, the three-shaft transmission gear 131 is in sliding connection with the transmission three shaft 13 through the spline, the three-shaft transmission gear 131 is connected with a shifting fork, and the three-shaft transmission gear 131 is controlled by the shifting fork to move axially along the transmission three shaft 13. The rotary tillage driven gear 132 is a duplicate gear, the diameter of a large gear of the rotary tillage driven gear 132 is equal to the diameter of the three-shaft transmission gear 131 (in fig. 1, the three-shaft transmission gear 131 is overlapped with the large gear of the rotary tillage driven gear 132), the large gear of the rotary tillage driven gear 132 can be meshed with the rotary tillage driving gear 122, the rotary tillage driven gear 132 is rotatably supported at the upper end of the transmission three shaft 13, specifically, the inner ring of the rotary tillage driven gear 132 is rotatably supported at the upper end of the transmission three shaft 13 through a copper sleeve (not shown), and the rotary tillage driven gear 132 is axially positioned through a retaining ring (not shown).

The four-shaft transmission gear 141 and the four-shaft transition gear 142 are arranged on the four transmission shaft 14, the four transmission shaft 14 is a spline shaft, the four-shaft transmission gear 141 and the four-shaft transition gear 142 are in spline static connection with the four transmission shaft 14, the four-shaft transmission gear 141 and the four-shaft transition gear 142 rotate synchronously with the four transmission shaft 14, the thickness of the four-shaft transmission gear 141 is two times larger than that of the three-shaft transmission gear 131, and the thickness of the four-shaft transmission gear 141 is larger, so that the four-shaft transmission gear 141 is always meshed with the three-shaft transmission gear 131 no matter the three-shaft transmission gear 131 is meshed with the two-shaft transmission gear 121 or meshed with the large gear of the reverse double-gear 101.

The five-shaft transmission gear 151 and the high-low gear driving gear 152 are arranged on the five transmission shaft 15, the five transmission shaft 15 is a spline shaft, the five-shaft transmission gear 151 and the five transmission shaft 15 are in spline static connection, the high-low gear driving gear 152 is a duplicate gear, the high-low gear driving gear 152 and the five transmission shaft 15 are in spline sliding connection, a fixed shifting fork is connected onto the high-low gear driving gear 152, the high-low gear driving gear 152 can axially move along the five transmission shaft 15 under the control of the shifting fork, and the five transmission shaft 151 is meshed with the four-shaft transition gear 142.

The six transmission shafts 16 are provided with six transmission gears 161, a high-gear driven gear 162 and a low-gear driven gear 163, the six transmission shafts 16 are spline shafts, the six transmission gears 161, the high-gear driven gear 162 and the low-gear driven gear 163 are in spline static connection with the six transmission shafts 16, the six transmission gears 161, the high-gear driven gear 162 and the low-gear driven gear 163 rotate synchronously with the six transmission shafts 16, the six transmission gears 161 are located in the middle of the six transmission shafts 16, the high-gear driven gear 162 and the low-gear driven gear 163 are located on two sides of the six transmission gears 161, and the diameter of the high-gear driven gear 162 is smaller than that of the low-gear driven gear 163.

The seven transmission shafts 17 are used for driving the mini-tiller to walk, the driving gear 171 is arranged in the middle of the seven transmission shafts 17, the driving gear 171 is meshed with the six-shaft transmission gear 161, in actual farming, the seven transmission shafts 17 are provided with driving wheels with the outer diameter of 380mm, the outer diameters of the driving wheels can be set according to actual farming needs of the actual mini-tiller, and specific limitation is not made one by one here.

The eight transmission shafts 18 are provided with eight transmission gears 181 and eight transition gears 182, the eight transmission shafts 18 are spline shafts, the eight transmission gears 181 and the eight transition gears 182 are in spline static connection with the eight transmission shafts 18, the eight transmission gears 181 and the eight transition gears 182 rotate synchronously with the eight transmission shafts 18, and the eight transmission gears 181 are meshed with the pinions of the rotary tillage driven gears 132.

Nine-shaft transmission gears 191 and nine-shaft transmission chain wheels 192 are arranged on the nine transmission shafts 19, the nine transmission shafts 19 are spline shafts, the nine transmission gears 191 and the nine transmission chain wheels 192 are in spline static connection with the nine transmission shafts 19, the nine transmission gears 191 and the nine transmission chain wheels 192 rotate synchronously with the nine transmission shafts 19, and the nine transmission gears 191 are meshed with the eight transition gears 182.

The rotary tillage case includes rotary tillage box 2 and rotary tillage axle 21, rotary tillage box 2 couples in transmission box 1 right side through the screw slope, the axle journal at rotary tillage axle 21 both ends is adorned respectively and is fixed in the bearing on rotary tillage box 2, be provided with rotary tillage sprocket 22 on the rotary tillage axle 21, the cover is equipped with chain 23 on rotary tillage sprocket 22 and the nine drive sprocket 192, transmit rotary tillage sprocket 22 and rotary tillage axle 21 through chain 23 with the power of the nine 19 outputs of transmission, rotary tillage axle 21 both ends mountable rotary tillage blade disc or harrow wheel, can realize carrying out the plow harrow to the field, the rotary tillage, satisfy user's different operation demands. The rotary tillage chain wheel 22 in the main transmission box and the nine-shaft transmission chain wheel 192 in the rotary tillage box are sleeved with the chain 23 for power transmission, the distance between the rotary tillage shaft 21 and the nine transmission shafts 19 can be set to be larger, so that the chain 23 and the rotary tillage box body 2 with longer length can be used, rotary tillage cutter heads or harrowing wheels with larger size can be installed at two ends of the rotary tillage shaft 21, and the farming requirement of the larger field depth is met.

When the utility model is used, when the shifting fork is used for controlling the rotary tillage driving gear 122 to axially move along the transmission two-shaft 12, so that the rotary tillage driving gear 122 is meshed with the large gear of the rotary tillage driven gear 132, the power output by the engine can be transmitted to the rotary tillage shaft 21 through the transmission eight-shaft 18, the transmission nine-shaft 19, the nine-shaft transmission chain wheel 192, the chain 23 and the rotary tillage chain wheel 22 in sequence, and the plowing and rotary tillage of a field can be realized through the rotary tillage cutterheads or harrowing wheels arranged at the two ends of the rotary tillage shaft 21; when the rotary tillage driving gear 122 moves to the neutral position (at this time, the rotary tillage driving gear 122 is not engaged with the large gear of the rotary tillage driven gear 132), the rotary tillage driving gear 122 idles around the transmission secondary shaft 12, and the rotary tillage shaft 21 does not rotate; when the shifting fork is used for controlling the three-shaft transmission gear 131 to axially move along the three transmission shafts 13, so that the three-shaft transmission gear 131 is meshed with the two-shaft transmission gear 121, the mini-tiller moves forwards; when the shifting fork is used for controlling the three-shaft transmission gear 131 to axially move along the three transmission shafts 13, the three-shaft transmission gear 131 is meshed with the large gear of the reverse gear duplicate gear 101 to be switched to a reverse gear, and the micro-farming machine walks backwards; because the rotary tillage driven gear 132 is rotatably supported at the upper end of the transmission three-shaft 13, no matter the micro-cultivator walks forwards or backwards, the rotating directions of the rotary tillage driven gear 132 and the rotary tillage shaft 21 are kept unchanged, so that the walking and the rotary tillage of the micro-cultivator are independent and do not influence each other; when the shifting fork is used for controlling the high-low gear driving gear 152 to axially move along the five transmission shafts 15, the large gear of the high-low gear driving gear 152 is meshed with the high-gear driven gear 162 on the six transmission shafts 16 to form a high gear, and the seven transmission shafts 17 rotate at a high speed to drive the mini-tiller to walk; when the pinion of the high-low gear driving gear 152 is meshed with the low-gear driven gear 163 on the transmission six-shaft 16 to form a low gear, the transmission seven-shaft 17 rotates at a lower speed to drive the micro-cultivator to walk; when the high-low gear driving gear 152 moves to the middle of the five transmission shafts 15 and is not meshed with the high-low gear driven gear 162 and the low-low gear driven gear 163, the five transmission shafts 15 idle, and the seven transmission shafts 17 do not rotate.

In the belt transmission case of the four-wheel-drive mini-tiller, the power output by an engine is transmitted to two sets of gears in the transmission case body 1, the gears are respectively used for transmitting walking power and rotary tillage power, and the transmission and disconnection of the walking power and the rotary tillage power are respectively and independently controlled, so that the walking of the mini-tiller and the tillage operation are independent and do not interfere with each other, namely, the forward or backward walking of the mini-tiller and the tillage operation can be simultaneously carried out, no matter the mini-tiller walks forwards or backwards, the rotation directions of a rotary tillage driven gear 132 and a rotary tillage shaft 21 are kept unchanged, and the mini-tiller can also be stopped in place to carry out plowing and rotary tillage on a field, or the mini-tiller does not carry out tillage operation when walking.

In addition, the belt transmission case of the four-wheel-drive mini-tiller drives the three-shaft transmission gear 131 to axially move along the three transmission shaft 13 through the shifting fork, the three-shaft transmission gear 131 is meshed with the two-shaft transmission gear 121 or the large gear of the reverse gear duplicate gear 101 on the reverse gear shaft 10, the thickness of the four-shaft transmission gear 141 is set to be two times larger than that of the three-shaft transmission gear 131, and the thickness of the four-shaft transmission gear 141 is larger, so that the four-shaft transmission gear 141 is always meshed with the three-shaft transmission gear 131 no matter the three-shaft transmission gear 131 is meshed with the two-shaft transmission gear 121 or the large gear of the reverse gear duplicate gear 101, the fast forward or backward walking switching of the mini-tiller is realized, the whole structure is simple and light, and the user can conveniently control the mini-tiller to move forward or backward.

In light of the foregoing description of the preferred embodiments of the present invention, it is to be understood that various changes and modifications may be made by those skilled in the art without departing from the spirit and scope of the utility model. The technical scope of the present invention is not limited to the content of the specification, and must be determined according to the scope of the claims.

Claims

1. The utility model provides a four-wheel drive ploughs quick-witted belt drive case a little, includes the main gear case and with the rotary tillage case of main gear case hookup, the main gear case includes transmission box, transmission one, transmission two axles, reverse gear axle, transmission three-axis and transmission four-axis, and the transmission is epaxial to be provided with a drive gear, and the outer clutch of the outer adaptation belt drive formula of transmission box, its characterized in that are stretched out to one of them one end of transmission one: a two-shaft transmission gear and a rotary tillage driving gear are arranged on a transmission two shaft, the two-shaft transmission gear is meshed with a one-shaft transmission gear, the rotary tillage driving gear can move axially along the transmission two shaft, a reverse gear duplex gear is arranged on a reverse gear shaft, a small gear of the reverse gear duplex gear is meshed with the two-shaft transmission gear, a three-shaft transmission gear and a rotary tillage driven gear are arranged on the transmission three shaft, the peripheral side surface of the upper end of the transmission three shaft is a smooth cylindrical surface, a spline is arranged on the peripheral side surface of the lower end of the transmission three shaft, the three-shaft transmission gear is in sliding connection with the lower end of the transmission three shaft through the spline, the three-shaft transmission gear can be meshed with the two-shaft transmission gear or meshed with a large gear of the reverse gear duplex gear on the reverse gear shaft, the rotary tillage driven gear can be rotatably supported at the upper end of the transmission three shaft, the rotary tillage driven gear is a duplex gear, and the large gear of the rotary tillage driven gear can be meshed with the rotary tillage driving gear; four-axis drive gears and four-axis transition gears are arranged on the four drive shafts, the thickness of each four-axis drive gear is two times larger than that of each three-axis drive gear, and the four-axis drive gears are meshed with the three-axis drive gears.

2. The four-wheel-drive mini-tiller belt transmission case as claimed in claim 1, wherein: the main transmission box further comprises a five-axis transmission and a six-axis transmission, a five-axis transmission gear and a high-low gear driving gear are arranged on the five-axis transmission, the high-low gear driving gear is a duplicate gear, the high-low gear driving gear can axially move along the five-axis transmission, the five-axis transmission gear is meshed with a four-axis transition gear, a six-axis transmission gear, a high-gear driven gear and a low-gear driven gear are arranged on the six-axis transmission, a large gear of the high-low gear driving gear can be meshed with the high-gear driven gear to form a high gear, and a small gear of the high-low gear driving gear can be meshed with the low-gear driven gear to form a low gear.

3. The four-wheel-drive mini-tiller belt transmission case as claimed in claim 2, characterized in that: the main transmission box further comprises seven transmission shafts, a driving gear is arranged in the middle of each seven transmission shafts, the driving gears are meshed with the six transmission gears, and two ends of each seven transmission shaft are used for mounting driving wheels.

4. The four-wheel-drive mini-tiller belt transmission case as claimed in claim 3, wherein: the main transmission box further comprises eight transmission shafts and nine transmission shafts, eight transmission gears and eight transition gears are arranged on the eight transmission shafts, the eight transmission gears are meshed with the small gear of the rotary tillage driven gear, nine transmission gears and nine transmission chain wheels are arranged on the nine transmission shafts, the nine transmission gears are meshed with the eight transition gears, the rotary tillage box comprises a rotary tillage box body and a rotary tillage shaft, the rotary tillage box body is obliquely connected to the right side of the transmission box body, a rotary tillage chain wheel is arranged on the rotary tillage shaft, and a chain is sleeved on the rotary tillage chain wheel and the nine transmission chain wheels.

5. The four-wheel-drive mini-tiller belt transmission case as claimed in claim 4, wherein: the first transmission shaft, the second transmission shaft, the fourth transmission shaft, the fifth transmission shaft, the sixth transmission shaft, the eighth transmission shaft and the ninth transmission shaft are spline shafts, a first transmission gear is in static connection with the first transmission shaft through a spline, a second transmission gear is in static connection with the second transmission shaft through a spline, a rotary tillage driving gear is in sliding connection with the second transmission shaft through a spline, the rotary tillage driving gear is connected with a shifting fork, a fourth transmission gear and a fourth transmission gear are in static connection with the fourth transmission shaft through a spline, a fifth transmission gear is in static connection with the fifth transmission shaft through a spline, a high-low gear driving gear is in sliding connection with the fifth transmission shaft through a spline, a sixth transmission gear, a high-low gear driven gear and a low-gear driven gear are in static connection with the sixth transmission shaft through a spline, an eighth transmission gear and an eighth transmission gear are in static connection with the eight transmission shaft through a spline, and a ninth transmission sprocket is in static connection with the ninth transmission shaft through a spline.

6. The four-wheel-drive mini-tiller belt transmission case as claimed in claim 1, wherein: the inner ring of the reverse gear duplicate gear is rotatably supported on the reverse gear shaft through a copper sleeve, and the reverse gear duplicate gear is axially positioned through a check ring.

7. The four-wheel-drive mini-tiller belt transmission case as claimed in claim 1, wherein: the inner ring of the rotary tillage driven gear is rotatably supported at the upper end of the transmission three shaft through a copper sleeve, and the rotary tillage driven gear is axially positioned through a check ring.