CN201393362Y

CN201393362Y - Multifunctional rotary cultivator as well as extending shaft and speed change gear box convenient for reversal thereof

Info

Publication number: CN201393362Y
Application number: CN2009200455497U
Authority: CN
Inventors: 葛伟岸; 葛玉明
Original assignee: Individual
Current assignee: Individual
Priority date: 2009-05-20
Filing date: 2009-05-20
Publication date: 2010-02-03
Anticipated expiration: 2019-05-20

Abstract

The utility model discloses a multifunctional rotary cultivator as well as extending shaft and speed change gear box convenient for reversal thereof. The coulter shaft of the rotary cultivator is connected with the power device of a tractor through the speed change gear box; the colter shaft is mounted with a rotary colter. The multifunctional rotary cultivator as well as extending shaft and speedchange gear box convenient for reversal thereof is characterized in that at least one end of the colter shaft is provided with a connecting mechanism used for connecting the extending shaft. The extending shaft is the cutter shaft of a ditcher, the cutter shaft of a stubble covering machine or the colter shaft of the rotary cultivator. The gear box of the multifunctional cultivator of the preferable proposal is divided into two parts which comprise an upper shell and a lower shell; the mounting on-off gaps of the upper shell and the lower shell are arranged at the position of the centre lineof the bearing hole of a driven cone gear shaft on the upper part of the gear box; the upper shell and the lower shell are fixedly connected through a bolt. Based on guaranteeing the function of the original rotary cultivator, the multifunctional rotary cultivator as well as extending shaft and speed change gear box convenient for reversal thereof can obtain the functions of stubble covering and ditching as well as other functions only by simply adjusting and increasing a small amount of part accessories. The gear box is convenient to be dismounted, which is beneficial for adjusting the mounting pattern and maintenance of gears, extensively reducing the purchasing cost of farmers, being convenient to be mounted and saving the farming hours.

Description

Multifunctional rotary cultivator, extension shaft thereof and speed change gear box capable of conveniently reversing

Technical Field

The utility model belongs to the field of agricultural machinery, concretely relates to can expand for having the multi-functional rotary cultivator of uses such as burying stubble and ditching to and the last extension axle of this kind of multi-functional rotary cultivator and above can make things convenient for the change gear box that reverses.

Background

The existing farmland rotary cultivator hung at the rear part of a tractor is a machine type which is widely used in agricultural machinery and has a very long history, and the structure and the working principle are as follows: the power of the tractor is transmitted through a pair of bevel gears and a plurality of cylindrical gears to drive the coulter shaft, so that the lower edge of the rotary blade on the coulter shaft rotates backwards (rotates forwards) to cut up and turn over the soil.

The rotary cultivator has the main defects that the rotary cultivator has a single function and can only be used for farmlands with few straws, a plurality of field blocks with a lot of straws are left on the ground surface after crops such as wheat and rice are planted and the straws cannot be buried into the soil during rotary cultivation, a reverse stubble burying machine needs to be additionally purchased by farmers, and a ditching machine needs to be purchased again when ditching is needed. Therefore, farmers need to buy three agricultural machines with different purposes, which not only has high cost, but also wastes time and labor in the process of disassembling and assembling the farm machine and the tractor because the matched agricultural machines with different functions need to be replaced for different purposes frequently during the farmland operation; secondly, the gear box of the rotary cultivator is a whole, is troublesome to disassemble and assemble, and is inconvenient to adjust and maintain.

Disclosure of Invention

The utility model aims at: the multifunctional rotary cultivator is redesigned and innovated, and on the basis of ensuring the function of the original rotary cultivator, the functions of stubble burying, ditching and other purposes can be obtained only by simply adjusting and adding a small number of parts. The gear box is convenient to disassemble and assemble, the assembly mode and the maintenance of the gear can be adjusted, the machine purchasing cost of farmers can be greatly reduced, the gear box is convenient to install, and the farming season is saved. The utility model discloses the extension axle on still will providing this kind of multi-functional rotary cultivator and the change gear case that can conveniently overturn on it.

The scheme for completing the first invention task is as follows: a multifunctional rotary cultivator is composed of a plough-shank linked to power unit of tractor via speed-varying gear box, and a rotary tiller installed to said plough-shank.

The coupling mechanism for coupling the elongate shaft may be one of the following:

1. the coupling mechanism is a male-female insertion structure:

at least one end (preferably both the left and right ends) of the colter shaft is provided with a hollow cylindrical section (a main shaft); the connecting end of the extending shaft (or called extending shaft) to be connected with the hollow cylindrical section is provided with a protruding shaft (male shaft) which has the same length as the hollow cylindrical section and the same inner diameter as the hollow cylindrical section; a key and a locking positioning pin are arranged between the two; or,

at least one end (preferably both the left and right ends) of the colter shaft is provided with a protruding shaft (male shaft); the connecting end of an extension shaft (or called extension shaft) to be connected with the hollow cylindrical section (female shaft) is provided with the same length and the same diameter; a key and a locking positioning pin are arranged between the two.

The cross section of the hollow cylindrical section and the protruding shaft can be spline, round, polygonal or square.

2. The coupling mechanism is a spiral coupling structure:

at least one end (preferably both the left and right ends) of the colter shaft is provided with an internal thread section; the connecting end of the extending shaft to be connected with the connecting end is provided with an external thread section; or, conversely, at least one end of the coulter shaft (preferably both the left and right ends) is provided with an external thread section; the coupling end of the elongate shaft to be coupled thereto is provided with an internally threaded section.

The extension shaft (or called extension shaft) can be a cutter head shaft of a ditcher, a stubble-burying cutter head shaft or still be a colter shaft of a rotary cultivator (namely, the rotary cultivator which becomes a wider working face after being connected).

Connecting the extending shafts, such as a cutter disc shaft and a stubble burying cutter disc shaft of a ditcher, at least one end (preferably at the left end and the right end) of the colter shaft, and then changing the rotating direction of the operating shaft (colter shaft) into reverse rotation to bury stubbles or ditch; or the rotary cultivator with wider working surface can be formed by connecting the extension shafts of the colter shafts of the rotary cultivator without changing the rotating direction of the colter shafts. This shows that above scheme can reach the purpose of the utility model, namely, on the basis of guaranteeing original rotary cultivator function, only need simple regulation and increase a small amount of part accessories can obtain the function of burying stubble, ditching and other usage.

However, in order to make the effect of ditching and burying the stubble more ideal, above scheme can further improve, when ditching and burying the stubble operation, the direction of rotation of transform operation axle (colter axle) is more simple and convenient, the utility model discloses there is following optimization scheme:

the gear box of the multifunctional rotary cultivator is divided into an upper shell and a lower shell, and an assembling opening and closing seam of the upper shell and the lower shell is arranged at the center line of a bearing hole at the shaft end of a driven bevel gear at the upper part of the gear box; the upper shell and the lower shell are fastened by bolts. The structure constitutes a change speed gear box which can be conveniently reversed.

The central line of the bearing hole of the driven bevel gear shaft at the upper part of the gear box refers to a larger range near the central line; the assembling device comprises an assembling opening and closing seam which is horizontally arranged, wherein the opening and closing seam can pass through the centers of driven and driving bevel gear bearing holes; or the inclined line is provided with an assembling opening and closing seam which only passes through the center of the driven bevel gear bearing hole and the like. The key is that the driven bevel gear is easy to disassemble and turn to install from the gear box, and the fit clearance between the bearing and the assembly hole on the gear box cannot be enlarged even if the driven bevel gear is disassembled and assembled for many times.

The structure is easy to open the gear box to change the rotation direction of the operation shaft (colter shaft), so that the rotary tillage operation and the stubble burying and ditching operation are very convenient to change.

It should be noted that: the utility model discloses a multifunctional rotary cultivator, as long as be provided with the coupling mechanism who is used for linking the extension axle at least one end or both ends of coulter shaft, can constitute new product, can sell alone under the condition of not disposing any extension axle (or being called extension axle). And the extension shaft (the cutter head shaft, the stubble burying cutter head shaft or the extension shaft of the colter shaft of the rotary cultivator can also comprise a cutter head of a ditcher and a stubble burying cutter head on the extension shaft) matched with the extension shaft, or the gear box of the multifunctional rotary cultivator can respectively and independently form a product for independent sale. But all belong to the technical scheme of the utility model.

The utility model discloses when expanding out the ditching machine following optimization scheme in addition:

the cutter head of the ditcher adopts an axially adjustable fixing mode on the cutter head shaft, so that the distance between the cutter head and the central line of the tractor can be conveniently adjusted;

the shaft on the two sides of the cutter head of the ditcher is also provided with a field leveling and soil leveling cutter, a detachable installation mode is adopted between the soil leveling cutter and the cutter head of the ditcher, and the soil leveling cutter can adopt a rotary tillage cutter. The function is to eliminate the accumulated soil on the two sides of the ditches.

The scheme for completing the 2 nd invention task of the present application is as follows: the extension shaft of the multifunctional rotary cultivator is characterized in that at least one end (generally, only one end or the left end and the right end) of the extension shaft is provided with a connecting mechanism for connecting with one end of a plough coulter shaft of the rotary cultivator; the elongate shaft is one of the following structures: a cutter head of the ditcher is assembled on the cutter head shaft of the ditcher; or a colter shaft of the rotary cultivator, which is provided with a rotary blade; or a cutter head shaft of the stubble burying machine, on which a stubble burying cutter is assembled.

The scheme for completing the 3 rd invention task of the present application is as follows: the speed change gear box convenient for reverse rotation on the multifunctional rotary cultivator is internally provided with a bevel gear pair and is characterized in that a gear box body is divided into an upper shell and a lower shell, and an assembly opening and closing seam of the upper shell and the lower shell is arranged at the central line of a bearing hole of a driven bevel gear shaft; the upper shell and the lower shell are fastened by bolts.

The central line of the bearing holes of the two bevel gear shafts on the upper part of the gear box refers to that: the assembly opening and closing seam of the box body is superposed or basically close to the center of the bearing hole; the setting mode includes: horizontally arranging an assembling opening and closing seam; the assembling opening and closing seam is arranged obliquely (oblique line).

In other words, in order to achieve the above-mentioned multi-functional purpose, a technical solution which is suitable for different purposes, simple in structure, low in cost, reliable and durable, and convenient to assemble and adjust must be sought. On the basis through a large amount of studies and repeated experiments, the utility model provides a two break traditional custom thinking, seem simple but have the technical scheme of special positive effect, and its main core content is:

1. the outer ends of the left side and the right side of the colter shaft of the rotary cultivator are provided with mechanisms connected with the extension shaft; the extension shaft is tightly connected with the colter shaft when needed; the extension shaft and the colter shaft are fastened by a key or a pin which is coupled with each other to transmit torque; the extension shaft and the colter shaft can be conveniently assembled and disassembled.

2. The gear box of the rotary cultivator is divided into an upper shell and a lower shell, and an assembling opening and closing seam of the upper shell and the lower shell is arranged at the center line of a bearing hole of a driven bevel gear shaft at the upper part of the gear box; or the central lines of the bearing holes of the two bevel gear shafts, and the side walls of the upper shell and the lower shell of the gear box are respectively provided with a semi-circular bearing assembly concave arc. The upper shell and the lower shell are fastened by bolts.

The utility model has the advantages that:

1. firstly, the function of the rotary cultivator is fully ensured. The rotary cultivator is the most used type in agricultural machinery, and the extension shafts at two ends of the colter shaft are disassembled, so that the rotary cultivator is a product with the same function as a common professional rotary cultivator, and the problems of cost increase, inconvenience in walking and the like are solved.

2. Simple structure, installation regulation and increased function are very convenient. When the operations such as ditching and the like are needed, the extension shaft and the colter shaft are connected and fastened, and then accessories such as a ditching cutter head, a soil dividing plate and the like are installed, so that the ditching operation can be carried out; in the field with soft soil or light load and needing only shallow rotary tillage, the lengthened coulter shaft with the rotary tillage blades can be assembled on the lengthened shaft, so that the lengthened coulter shaft is expanded into a large-width rotary cultivator, and the power and the efficiency of the tractor are fully utilized.

3. The gear box is convenient to disassemble and assemble, low in cost and good in reliability. From the evaluation of stubble burying effect, the rotary cultivator coulter has better reverse rotation than forward rotation, namely the lower edge of the coulter shaft rotates towards the forward direction of the tractor. In the prior art, if the coulter shaft of the forward rotary cultivator is changed into reverse rotation, the gear box of the rotary cultivator needs to be disassembled, the direction of the driven bevel gear is adjusted, because the bearing on the bevel gear shaft and the bearing hole of the gear box need to be in tight transition fit, the parts in the gear box need to be disassembled and reassembled, the coulter shaft can be operated only by a special tool with certain technical capability, and common farmers can not finish the operation in the field. If the complex shifting fork change gear and other mechanisms are adopted for steering adjustment, the complexity of the internal structure of the gear box can be increased, the cost is increased, the weight is increased, and the gear box is easy to damage. The utility model divides the gear box into an upper shell and a lower shell, and the assembling opening and closing seam of the upper shell and the lower shell is arranged at the center line of the bearing holes of two bevel gear shafts at the upper part of the gear box; the upper shell and the lower shell are connected and fastened by bolts, and the driven bevel gear can be conveniently adjusted to rotate reversely by only dismounting the connecting bolts at the joint. The disassembly and assembly time is very short, the work can be completed without the need of more skilled technology and complex special tools, and much time is saved compared with the replacement of one agricultural machine. The bearing assembly holes formed by the two semicircular arcs are not abraded during assembly and disassembly, so that the fit clearance cannot be enlarged, and the assembly precision can be ensured due to the clearance compensation function.

Because these parts are the spare part, be convenient for a person to carry, the construction, it is far more laborsaving and convenient than changing another kind of holistic agricultural machinery. The special stubble burying machine or the ditching machine has the weight of about 380 kilograms, farmers do not have lifting equipment such as a forklift and the like, and can disassemble and assemble the special stubble burying machine or the ditching machine only by the cooperative work of four or five strong labors.

4. The cost is greatly saved. Each of the three agricultural machines of rotary tillage, stubble cleaning and ditching needs four to five thousand yuan, and the total of buying the three agricultural machines together is ten thousand yuan. The utility model can only increase the fittings of one hundred kilograms, increase the cost by one thousand and more, and save nearly half of the cost compared with buying three complete agricultural machines.

Drawings

Fig. 1 is a structural view of embodiment 1 shown from the rear view direction of a tractor;

FIG. 2 is a block diagram of an embodiment 2 of the assembly of the trenching cutter head on the elongate shaft 4 shown from the rear view of the tractor;

FIGS. 3-1 and 3-2 are structural views corresponding to FIG. 2, shown from the right side direction of the tractor; oblique (oblique) arrangements respectively representing the assembly opening and closing seams; horizontally arranging;

FIG. 4 is a schematic structural view of an embodiment of the rotary cultivator expanded to a wide width;

FIG. 5 is a right side view of an embodiment of the multi-functional rotary tiller configured for use with a hand tractor;

fig. 6 is a top view a-a of fig. 5.

Detailed Description

Embodiment 1, the utility model discloses a multifunctional rotary cultivator, figure 1 is the structure of embodiment 1 shown from the rear view direction of tractor: in fig. 1: 1. the lower shell of the gear box, 2, a colter shaft, 3, a locking pin, 4, an extension shaft, 5, a rotary cultivator frame, 6, a tractor driving wheel, 7, a universal joint, 8, the upper shell of the gear box, 9, a connecting bolt, 10 and a stubble blocking grid. In the figure 1, the colter shaft 2 is a circular tube structure, inner splines are arranged on the inner walls of two ends of the colter shaft, the extension shaft 4 is inserted into the colter shaft 2, the section of the extension shaft is an external spline corresponding to the inner wall of the circular tube of the colter shaft 2, and the colter shaft and the extension shaft are positioned by the locking pin 3 to transmit torque. The section shape of the connection and matching of the extension shaft 4 and the tubular coulter shaft 2 can also be polygonal, square or directly cylindrical, the locking pin 3 is used for axially positioning to transmit torque, the coulter shaft 2 can be flush with the outer side of the rotary cultivator frame 5, and can also extend out of the rotary cultivator frame 5 for a certain distance, if the two ends of the coulter shaft 2 are solid circles, the section of the shaft can extend out of the outer side of the rotary cultivator frame 5 for a certain length, the extension shaft 4 adopts a circular tube type structure and is sleeved and inserted on the coulter shaft 2 extending out of the rotary cultivator frame 5, and the section shape can still adopt the various structures;

as can be seen from figure 1, the opening and closing seam of the gear box is arranged at the center line of the bearing of the bevel gear shaft at the upper part of the opening and closing seam, so that the gear box forms two parts of an upper shell 8 and a lower shell 1 of the gear box and is fastened by a connecting bolt 9 on a flange ring at the periphery of the gear box. When the stubble-burying rotary tillage needs to be carried out in a reverse rotation mode, the connecting bolt 9 is detached, the upper shell 8 of the gear box is uncovered, the driven bevel gear and the shaft can be adjusted in rotation direction, the colter shaft is enabled to rotate in the reverse direction, soil blocks and straws are thrown upwards by the reverse colter, the soil blocks are thrown out from the grids through filtration of the stubble-burying grids, the straws of rice, wheat and the like are blocked by the stubble-burying grids 10 and fall down, and then the straws are buried and covered by the highly-thrown soil blocks, so that the stubble-burying effect is achieved.

Embodiment 2, a multifunctional rotary cultivator equipped with a ditching cutter head, fig. 2 is a structure of embodiment 2 equipped with a ditching cutter head on an extension shaft 4, which is shown from the rear view direction of a tractor, and in fig. 2: 1. the rotary cultivator comprises a lower gear box shell, 2, a colter shaft, 3, a locking pin, 4, an extension shaft, 5, a rotary cultivator frame, 6, a tractor driving wheel, 7, a universal joint, 8, an upper gear box shell, 9, a connecting bolt, 10, a stubble blocking grid, 11, a ditching cutter head, 12, a rotary tillage cutter, 13, a soil separating plate and 15 nuts.

Fig. 3 is a structural view corresponding to fig. 2, shown from the right side direction of the tractor, in which: 1. gear box lower casing, 4, extension axle, 5, rotary cultivator frame, 6, tractor drive wheel, 7, universal joint, 8, gear box upper casing, 9, connecting bolt, 11, ditching blade disc, 12, rotary blade. In the figure, the soil separating plate 13 plays a role of throwing soil milled by the ditching cutter head to two sides, if the ditching cutter head 11 rotates anticlockwise, namely rotates reversely, the soil separating plate 13 is arranged at the front upper part of the ditching cutter head, and if the ditching cutter head 11 rotates clockwise, namely rotates clockwise, the soil separating plate 13 is arranged at the rear upper part of the cutter head. The blade on the ditching cutter head 11 can also be a universal rotary tillage blade, and the arrangement direction of the blade is suitable for the turning direction. The rotary blades 12 are arranged on two sides of the ditching cutter head, the rotary radius of the rotary blades 12 can be adjusted, the effect of leveling soil blocks on two sides of the ditch is achieved, soil crumbs on two sides of the ditch are prevented from being accumulated to be too high to form a ridge, and drainage is facilitated.

Embodiment 3, a wide-width multifunctional rotary cultivator. Fig. 4 is a schematic view of the extension of the wide rotary cultivator with the rotary blade mounted on the extension shaft, fig. 4 is also a rear view directional diagram of the tractor, wherein: 1. the rotary cultivator comprises a lower gear box shell, 2 parts of a colter shaft, 3 parts of a locking pin, 4 parts of an extension shaft, 5 parts of a rotary cultivator frame, 6 parts of a tractor driving wheel, 7 parts of a universal joint, 8 parts of an upper gear box shell, 9 parts of a connecting bolt, 10 parts of a stubble blocking grid, 12 parts of a rotary tillage cutter. The coulter shaft tube 14 is a round tube structure, is provided with a plurality of rotary tillage cutters 12, is sleeved on the extension shaft 4, has keys coupled with the extension shaft 4 and other structures for transmitting torsion, and is externally screwed by a nut 15.

If the function of the rotary cultivator needs to be recovered, the extension shaft, the ditching cutter head on the shaft and other parts can be removed, and a dustproof cover is additionally plugged at the hole where the extension shaft is inserted into the frame of the rotary cultivator. If the connecting mechanism of the colter shaft and the extension shaft protrudes out of the side frame of the rotary cultivator, a dustproof sleeve is added.

FIGS. 1-3 (including FIGS. 3-1 and 3-2) are a rotary cultivator type in which a pair of bevel gears and all cylindrical gears are arranged in a gear box in the middle to directly drive a left colter shaft and a right colter shaft in the middle, or a rotary cultivator type in which only a pair of bevel gears is arranged in the middle and the cylindrical gear below the bevel gears is arranged on one side of a rotary cultivator frame, the shaft of a driven bevel wheel is lengthened, and power is transmitted to the cylindrical gear or chain on the side to drive the colter shafts to drive.

Embodiment 4, right side view of the embodiment of the multifunctional rotary cultivator matched with the walking tractor. The structure is shown in FIG. 5. Fig. 6 is a top view a-a of fig. 5. In the figure: 1. the ditching cutter head, 2, an extension shaft, 3, a ditching blade, 4, a soil homogenizing cutter, 5, a rotary cultivator, 6, a locking pin, 7, a rotary cultivator colter shaft, 8, a rotary cultivator gear box, 9, a reversing gear box, 10, a tractor driving wheel, 11, a tail wheel, 12, a seat, 13, a soil separating plate, 14, a clutch handle, 15 and a hand tractor.

In the multi-functional rotary tiller matched with the walking tractor 15 shown in fig. 5 and fig. 6, the rotary tiller shaft 7 is also of a hollow circular tube structure, the end part of the rotary tiller shaft 7 is provided with a connecting device matched with the extension shaft 2, the extension shaft 2 is connected with the connecting device of the rotary tiller shaft 7 when ditching is needed, the ditching cutter head 1 is arranged on the extension shaft 2, a soil separating plate 13 is arranged above the ditching cutter head 1, the front part of the rotary tiller gear box 8 is also provided with a commercially available universal reversing gear box 9, and the rotary tiller shaft 7 is rotated anticlockwise or reversely by one or a plurality of odd-numbered gears in the reversing gear box 9. The reversing gear box 9 is added to prolong the horizontal distance between the coulter shaft 7 of the rotary cultivator and the front and back of the driving wheel 10 of the hand tractor 15, so that the ditching cutter head 1 can obtain larger space and lifting height, and soil blocks can be thrown in the process of walking and ditching. The height of the tail wheel from the ground is adjusted, so that the ditching depth can be adjusted.

During ditching operation, the clutch handle 14 is pulled to switch on power, so that the colter shaft 7, the extension shaft 2 and the ditching blade 3 on the ditching cutter head 1 are used for cutting soil into pieces and projecting the pieces towards the upper part, the pieces are thrown to two sides of a ditch through the V-shaped soil distribution plate 13, the two sides of the cutter head 1 are also provided with soil homogenizing cutters 4, the broken soil on two sides of the ditch can be homogenized, and the situation that the broken soil on the ditch sides is accumulated too high to form a soil ridge to influence drainage is prevented.

Because the end part of the colter shaft 7 of the rotary cultivator is provided with the special structure which is matched and connected with the extension shaft 2, the ditching cutter head can be arranged at the side of the hand tractor 15, no barrier is arranged in front of the ditching cutter head, a necessary space is created for the cutter head 1 to reversely throw soil forwards, and the soil throwing uniformity is improved. And because the ditching cutter head 1 is laterally arranged beside the operator, compared with the prior art that the ditching cutter head is positioned in the middle, the safety of the operator is improved, the influence of dust generated during operation on people is also obviously reduced, and the ditch can be opened to the edge of the field.

The ditching cutter head and the extension shaft are dismantled, the universal rotary cultivator can be recovered, the cost of the multifunctional rotary cultivator with rotary tillage and ditching is greatly reduced compared with the cost of purchasing two special rotary cultivators and a rear-mounted ditcher, the multifunctional rotary cultivator is convenient for farmers to install and use, and more importantly, the combined ditcher has improved soil throwing uniformity during ditching, adaptability to fields, safety to operators and protection to dust.

Example 5 the trenching cutter head and cutter head shaft of the above examples as elongate shafts were produced and sold separately as products.

Example 6 the rotary tiller extension shaft as the extension shaft in the above examples was produced and sold separately as a product.

Example 7, the stubble-burying cutter head shaft as the elongate shaft in the above examples, was produced and sold as a product alone.

Embodiment 7, the conveniently reversible change speed gear box of the above embodiment is produced and sold as a product alone.

Claims

1. A multifunctional rotary cultivator is characterized in that at least one end of a colter shaft is provided with a connecting mechanism for connecting an extension shaft.

2. The multi-functional rotary cultivator of claim 1, wherein the coupling mechanism for coupling the elongated shaft is one of: the coupling mechanism is a male-female insertion structure, or a spiral coupling structure.

3. The multi-functional rotary cultivator of claim 1, wherein the elongate shaft is a ditcher cutter shaft, a stubble burying cutter shaft, or a coulter shaft of the rotary cultivator.

4. The multi-functional rotary cultivator of claim 3 wherein the cutter head shaft of the ditcher as an elongated shaft is fixed to the cutter head shaft in an axially adjustable manner.

5. The multifunctional rotary cultivator of claim 3 or 4, wherein the shafts on both sides of the cutter head of the ditcher are provided with soil leveling blades, the soil leveling blades and the cutter head of the ditcher are detachably mounted, and the soil leveling blades are rotary tillage blades.

6. The multifunctional rotary cultivator of claim 1, 2 or 3, wherein the gearbox of the multifunctional rotary cultivator is divided into an upper shell and a lower shell, and the assembling opening and closing seam of the upper shell and the lower shell is arranged at the center line of the bearing hole of the driven bevel gear shaft at the upper part of the gearbox; the upper shell and the lower shell are fastened by bolts.

7. The multifunctional rotary cultivator of claim 6, wherein the arrangement mode of the assembling opening and closing seams of the upper shell and the lower shell of the speed change gear box is as follows: horizontally arranging an assembling opening and closing seam; or the assembling opening and closing seam is obliquely arranged.

8. An elongate shaft on a multi-function rotary tiller as claimed in claim 1, wherein at least one end of the elongate shaft is provided with coupling means for coupling with an end of a tiller shaft; the elongate shaft is one of the following structures: a cutter head of the ditcher is assembled on the cutter head shaft of the ditcher; or a colter shaft of the rotary cultivator, which is provided with a rotary blade; or a cutter head shaft of the stubble burying machine, on which a stubble burying cutter is assembled.

9. The conveniently reversible speed change gear box of the multifunctional rotary cultivator of claim 1, wherein a bevel gear pair is arranged in the gear box, and the gear box body is divided into an upper shell and a lower shell, and an assembling opening and closing seam of the upper shell and the lower shell is arranged at the central line of a bearing hole of a driven bevel gear shaft; the upper shell and the lower shell are fastened by bolts.

10. The conveniently reversible speed change gear box of the multifunctional rotary cultivator of claim 8, wherein the assembling opening and closing seams of the upper shell and the lower shell are arranged in a mode that: horizontally arranging an assembling opening and closing seam; or the assembling opening and closing seam is obliquely arranged.