Walking driving gearbox of agricultural machine

Abstract

The invention relates to the field of agricultural machinery gearboxes, in particular to an agricultural machinery walking driving gearbox which comprises a gearbox body, a shifting piece in the gearbox body is connected with a push rod, a round hole is formed in the gearbox body, the push rod extends out of the gearbox body through the round hole, one side of the gearbox body is fixedly provided with a locking block, and the locking block is fixedly installed on the other side of the gearbox body. And a through hole coaxial with the circular hole is formed in the locking block. A pushing rod is pushed to move towards one side through a pushing structure, a limiting column is driven to penetrate through a connecting groove from the interior of an annular locking groove in the middle to enter annular locking grooves in the two sides, the pushing structure continues to operate to push the pushing rod to rotate, and the limiting column rotates in the annular locking groove and is away from the connecting groove in one side; and the pushing rod is locked after gear engaging is completed, and the running stability and safety of the agricultural machine are guaranteed while the convenience of gear engaging operation is not affected.

Description

Technical Field

[0001] This invention relates to the field of agricultural machinery gearboxes, specifically to an agricultural machinery walking drive gearbox. Background Technology

[0002] The gearbox is the core component of the internal combustion engine transmission system. It changes the engine's output speed and torque by adjusting the gear combination to adapt to different driving conditions. When agricultural vehicles travel on uneven roads, the unevenness of the road surface will generate a large torsional vibration impact on the vehicle's output shaft. This impact is transmitted to the synchronizer sleeve through the output shaft. The synchronizer sleeve is softly locked by ball grooves. Large vibrations can cause the synchronizer sleeve to disengage from the engagement ring to a certain extent, resulting in the vehicle losing power. To address this issue, patent application CN117345865B provides a transmission shift lock assembly, transmission, and automobile. It uses a paddle inserted into a groove on the shift fork shaft, which improves the locking effect of the lock structure. Even if vibration occurs during driving, the paddle is not easy to disengage from the groove. Although the above structure can lock the shift fork shaft and prevent the vehicle from disengaging during driving, the groove on the shift fork shaft will cause stress concentration. Long-term operation will cause the shift fork shaft to break, which will seriously affect the service life of the shift fork shaft and the transmission. Moreover, the paddle needs to be pressed to lock during shifting, making shifting more complicated.

[0003] Therefore, a walking drive gearbox for agricultural machinery is proposed. Summary of the Invention

[0004] The purpose of this invention is to provide a walking drive gearbox for agricultural machinery, which solves the problem of locking the synchronizer sleeve of the gearbox while maintaining the ease of shifting and ensuring the service life of the gearbox without changing the shifting operation method.

[0005] To achieve the above objectives, the present invention provides the following technical solution: A walking drive gearbox for agricultural machinery includes a gearbox body. A push rod is connected to a paddle inside the gearbox body. A circular hole is formed on the gearbox body, through which the push rod extends to the outside of the gearbox body. A locking block is fixedly installed on one side of the gearbox body. A through hole coaxially arranged with the circular hole is formed in the locking block, through which the push rod extends. Multiple evenly arranged annular locking grooves are formed in the locking block. The through hole is coaxially arranged with and passes through the annular locking grooves. Multiple connecting grooves are formed in the locking block, connecting two adjacent annular locking grooves. Two symmetrically arranged limiting posts are installed on the push rod. A placement groove is formed at the end of each limiting post away from the push rod, where a roller is rotatably connected. The roller rolls within the annular locking groove. A pushing structure is installed on the push rod. When the gearbox shifts gears, the pushing structure drives the limiting post from the middle annular locking groove through the connecting groove into the two annular locking grooves on either side, where it rotates.

[0006] When agricultural vehicles travel over uneven roads, the roughness of the surface causes significant torsional vibration impacts on the output shaft. This impact is transmitted through the output shaft to the synchronizer sleeve, causing it to disengage from the engagement ring to some extent. This results in loss of power and affects driving stability and safety. To address this issue, the present invention aims to effectively lock the synchronizer sleeve after shifting, while maintaining the efficiency and stability of the transmission, preventing accidental disengagement due to external impacts or other factors. Furthermore, traditional transmissions often fail to shift properly or experience loose locking mechanisms, leading to shift failures and potentially damage to the transmission, severely impacting vehicle operation and lifespan. The transmission designed in this invention, by introducing key components such as annular locking grooves, connecting grooves, and limiting posts, and by having these components work synergistically, achieves more precise and reliable shifting and locking functions. Specifically, after the limit post is pushed into place, it needs to be rotated. This design ensures that the synchronizer sleeve can accurately move to the predetermined position after the push rod moves, thus ensuring smooth and stable shifting and effectively improving the overall performance and durability of the gearbox. During operation, the push structure pushes the push rod to one side and moves the limit post on the push rod, causing the limit post to pass through the connecting groove in the middle and enter the annular locking grooves on both sides. At this point, the push rod can no longer move. Since the push structure can no longer push the push rod to move, it will push the push rod to rotate, causing the limit post to rotate in the annular locking groove and move away from the connecting groove on one side, thereby locking the entire push rod. Due to the roller design, the limit post can reduce friction during rolling, improving the smoothness of shifting. Of course, the locking of the limit post only targets the pushing force generated by the output shaft vibration on the push rod and will not affect the normal operation of the shifting mechanism. By locking the push rod after shifting, the driving stability and safety of the agricultural machinery are ensured.

[0007] Preferably, the pushing structure includes a ball bearing, an mounting ring is fixedly mounted on the pushing rod, the ball bearing is rotatably connected to the mounting ring, a sleeve is slidably connected to the pushing rod, the sleeve is slidably connected to the through hole, the mounting ring is slidably connected to the sleeve, a guide groove is provided on the sleeve, the guide groove is generally S-shaped, the ball bearing is rotatably connected to the guide groove, a first compression spring is abutted on both sides of the mounting ring, the other end of the first compression spring on both sides abuts against the two ends of the sleeve, the first compression spring is sleeved on the pushing rod, and the sleeve is connected to the shifting mechanism.

[0008] When the gearbox shifts gears, the shifting mechanism drives the sleeve to slide along the push rod. Since the guide groove is S-shaped, the ball rolls in the guide groove as the sleeve slides. However, both sides of the mounting ring are abutted by the first compression spring. When the sleeve pushes the ball a certain distance through the first compression spring, it will first push the push rod to one side to perform the gear engagement operation, and drive the limit post and the roller on it to pass through the connecting groove and enter the annular locking groove on one side. When the push rod can no longer move, the sleeve will compress the first compression spring and make the ball roll in the guide groove. However, since the push rod can no longer move, the push rod will rotate at this time. The rotation will cause the limit post to swing away from the connecting groove on one side, thereby locking the push rod. This design allows the push rod to move smoothly and accurately to the predetermined position during gear shifting. Simultaneously, the sleeve returns to its original position under the action of the first compression spring, preparing for the next gear shift. After shifting gears by pushing the push rod with the sleeve, the sleeve continues to move and pushes the push rod to rotate and lock, ensuring that the push rod is locked in a certain position after the gear shifting operation is completed. This simple structure effectively locks the push rod while ensuring quick and easy gear shifting, preventing significant torsional vibration impacts when the vehicle is driving on uneven roads. When the output shaft transmits power to the synchronizer sleeve, the synchronizer sleeve pushes the push rod to move and disengages from the engagement gear ring, preventing the vehicle from losing power. Locking the push rod after gear shifting ensures the stability and safety of the agricultural machinery.

[0009] Preferably, a locking ring is fixedly installed on the push rod, and the locking ring is provided with multiple sliding holes. The limiting post is slidably connected in the sliding holes, and a second compression spring is installed in the sliding holes. The two ends of the second compression spring abut against the inner wall of the sliding hole and the limiting post, respectively. Both the locking ring and the mounting ring are divided into upper and lower half rings, and the two half rings are connected and fixed to the push rod by screws.

[0010] The design of setting a roller at one end of the limiting post allows the limiting post to slide within the sliding hole when subjected to external force, reducing the friction generated by the limiting post. The elastic force of the second compression spring ensures that the limiting post can always push the roller against the inner wall of the annular locking groove, thus ensuring that the limiting post can be stably locked in the annular locking groove. At the same time, the separate design of the locking ring and the mounting ring facilitates installation and disassembly. It should be noted that the two half rings are installed vertically, so that the two limiting posts are symmetrically arranged vertically, avoiding the gaps between the limiting posts and the locking blocks from overlapping. The locking ring and the mounting ring are installed with screws, which greatly improves the ease of maintenance of the gearbox.

[0011] Preferably, the cross-section of the annular locking grooves on both sides is a fan-shaped structure, with the vertical edges of the fan-shaped structures on both sides facing the central annular locking groove. The length of the limiting post is 'a', and the depth of the annular locking groove is 'b', where 0 < b < 0.5a. This design allows the limiting post to have a certain amount of room to move within the annular locking groove while still being effectively locked.

[0012] When the limiting post slides into the annular locking groove, the vertical edge of the fan-shaped structure faces the center, effectively causing the limiting post to abut against one side wall of the annular locking groove. Because the diameter of the limiting post is always smaller than the thickness of the annular locking groove, the limiting post can smoothly enter the groove. Any gaps created will cause the limiting post to wobble, leading to wobble in the synchronizer sleeve. The fan-shaped structure allows the roller to drive the limiting post into the annular locking groove, ensuring it is tightly against the vertical edge and achieving stable operation of the shifting mechanism. Furthermore, the depth of the annular locking groove is b. When b equals half the overall length of the limiting post, the distance the limiting post penetrates into the annular locking groove allows it to withstand greater force and torque, making it less prone to breakage due to external forces. However, this results in the annular locking groove experiencing the same compressive force as the protruding part of the push rod, potentially damaging the push rod. When b is less than half the overall length of the limiting post, the overall length of the limiting post on the push rod increases, raising the force-bearing area and preventing damage to the push rod, thus ensuring the stability and safety of the agricultural machinery.

[0013] Preferably, the distance between the two annular locking grooves is equal to the distance the push rod moves the paddle to one side. Both sides of the connecting groove are provided with arc-shaped chamfers, and the arc-shaped chamfers are asymmetrically arranged, with the radius of curvature on one side being half the radius of curvature on the other side.

[0014] This design allows the limiting post to slide smoothly from one annular locking groove to another during paddle shifting, reducing jamming and resistance during the shifting process. The curved chamfer design not only facilitates the entry and exit of the paddle, but also ensures that the radius of curvature on one side of the chamfer is half that on the other side, allowing the limiting post to slide more smoothly within the annular locking grooves on both sides during rotation. This reduces wear to some extent, extends the service life of the gearbox, ensures smooth gear shifting during agricultural machinery operation, and improves driving comfort and safety.

[0015] Preferably, multiple positioning holes are provided in the annular locking grooves on both sides. The depth of the positioning holes is less than half the radius of the roller. When the ball moves to the apex position on both sides of the guide groove, the roller enters the positioning hole.

[0016] At this point, the roller is firmly locked in the positioning hole, thus locking the push rod and ensuring that the shifting mechanism is in a stable shifting position. This design not only improves the shifting accuracy of the gearbox, but also prevents the roller from rotating on its own due to vibration or other external factors, thereby preventing the push rod from coming off the annular locking groove on one side due to unexpected circumstances, and ensuring the driving stability and safety of the agricultural machinery.

[0017] Preferably, the push rod is cast entirely from metal, and during casting, two annular protrusions are formed on the surface of the push rod, located on both sides of the locking ring. This design not only enhances the structural strength of the push rod but also limits the locking ring, preventing axial movement of the locking ring on the push rod. This ensures the stability of the connection between the locking ring and the push rod, preventing the locking ring and annular locking groove from failing to limit the push rod after it is pushed, thus avoiding displacement of the push rod. The annular protrusions ensure the locking ring locks the push rod securely, preventing significant torsional vibrations from occurring when the agricultural vehicle travels over uneven roads. When this vibration is transmitted to the synchronizer sleeve via the output shaft, the locking ring can limit the synchronizer sleeve via a paddle, preventing the synchronizer sleeve from disengaging from the engagement ring and causing the vehicle to lose power, thereby ensuring safe driving.

[0018] Preferably, the gearbox body has multiple threaded holes on one side, evenly distributed around the circular hole. The locking block consists of upper and lower parts, which are installed in the threaded holes with screws. The upper and lower parts of the locking block have a compact structure and reasonable design, which can effectively increase the connection strength between the locking block and the gearbox. The threaded holes not only facilitate the installation and removal of the locking block, but also ensure the stability of the locking block on the gearbox. In addition, the upper and lower parts of the locking block facilitate the installation of internal parts. However, a certain gap is inevitable when the two parts are joined, which will affect the rotation of the rollers. Therefore, when the two rollers are in the neutral position, they are arranged vertically, and the rotation is limited to a specific angle to prevent the rollers from rotating to the gap position, thereby ensuring the stable operation of the equipment.

[0019] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. The push mechanism moves the push rod to one side, causing the limiting post to pass through the connecting groove from the middle annular locking groove and into the annular locking grooves on both sides. As the push mechanism continues to operate, it will push the push rod to rotate, causing the limiting post to rotate within the annular locking groove and move away from the connecting groove on one side, thereby locking the entire push rod. After shifting gears, the push rod is locked, ensuring the stability and safety of the agricultural machinery while not affecting the convenience of shifting gears.

[0020] 2. After the sleeve pushes the push rod to move and engage the gear, the sleeve continues to move and pushes the push rod to rotate and lock, ensuring that the push rod can be locked in a certain position after the gear engagement operation is completed. Through a simple structure, the push rod is effectively locked while ensuring fast gear engagement, preventing the synchronizer sleeve from disengaging from the engagement gear ring and causing the vehicle to lose power, thus ensuring the driving stability and safety of the agricultural machinery.

[0021] 3. Because the diameter of the limiting post is always smaller than the thickness of the annular locking groove, the limiting post can smoothly enter the annular locking groove. The resulting gap will cause the limiting post to wobble, which will cause the synchronizer sleeve to wobble. The fan-shaped structure allows the roller to drive the limiting post into the annular locking groove and keep it close to the vertical side. This prevents the push rod from causing the synchronizer sleeve to wobble slightly after the push rod is locked, thus ensuring the stability and safety of the agricultural machinery. Attached Figure Description

[0022] Figure 1 This is a three-dimensional structural diagram of the present invention; Figure 2 This is a schematic diagram of the internal structure of the locking block in this invention; Figure 3 for Figure 2 Enlarged structural diagram at point A; Figure 4 This is a three-dimensional structural diagram of the sleeve in this invention; Figure 5 This is a schematic diagram of the internal structure of the sleeve in this invention; Figure 6 This is a schematic diagram of the moving structure of the push rod in this invention; Figure 7 This is a schematic diagram of the locking ring structure in this invention; Figure 8 This is a schematic diagram of the positioning hole in the present invention.

[0023] In the diagram: 1. Gearbox body; 2. Locking block; 3. Through hole; 4. Push rod; 5. Sleeve; 6. Locking ring; 7. Annular protrusion; 8. Annular locking groove; 9. Connecting groove; 10. Limiting post; 11. Roller; 12. Guide groove; 13. Mounting ring; 14. Ball bearing; 15. First compression spring; 16. Arc-shaped chamfer; 17. Fan-shaped structure; 18. Sliding hole; 19. Second compression spring; 20. Placement groove; 21. Positioning hole. Detailed Implementation

[0024] Please see Figures 1 to 8 This invention provides a walking drive gearbox for agricultural machinery, the technical solution of which is as follows: A walking drive gearbox for agricultural machinery includes a gearbox body 1. A push rod 4 is connected to a paddle inside the gearbox body 1. A circular hole is provided on the gearbox body 1, and the push rod 4 extends to the outside of the gearbox body 1 through the circular hole. A locking block 2 is fixedly installed on one side of the gearbox body 1. A through hole 3 is provided in the locking block 2, which is coaxial with the circular hole. The push rod 4 extends into the through hole 3. A plurality of evenly arranged annular locking grooves 8 are provided in the locking block 2. The through hole 3 is coaxial with and passes through the annular locking grooves 8. A plurality of connecting grooves 9 are provided in the locking block 2, which connect two adjacent annular locking grooves 8. Two symmetrically arranged limiting posts 10 are installed on the push rod 4. A placement groove 20 is provided at the end of the limiting post 10 away from the push rod 4. A roller 11 is rotatably connected in the placement groove 20 and rolls in the annular locking groove 8. A pushing structure is installed on the push rod 4. When the gearbox shifts gears, the pushing structure drives the limiting post 10 from the middle annular locking groove 8 through the connecting groove 9 into the annular locking grooves 8 on both sides and rotates.

[0025] The pushing structure includes a ball bearing 14, a mounting ring 13 fixedly mounted on the pushing rod 4, the ball bearing 14 rollingly connected to the mounting ring 13, a sleeve 5 slidably connected to the pushing rod 4, the sleeve 5 slidably connected to the through hole 3, the mounting ring 13 slidably connected to the sleeve 5, a guide groove 12 is provided on the sleeve 5, the guide groove 12 is generally S-shaped, the ball bearing 14 rollingly connected to the guide groove 12, a first compression spring 15 abutting against both sides of the mounting ring 13, the other end of the first compression spring 15 abutting against both ends of the sleeve 5 respectively, the first compression spring 15 is sleeved on the pushing rod 4, and the sleeve 5 is connected to the shifting mechanism.

[0026] A locking ring 6 is fixedly installed on the push rod 4. The locking ring 6 has multiple sliding holes 18. The limiting post 10 is slidably connected in the sliding hole 18. A second compression spring 19 is installed in the sliding hole 18. The two ends of the second compression spring 19 abut against the inner wall of the sliding hole 18 and the limiting post 10, respectively. The locking ring 6 and the mounting ring 13 are both divided into upper and lower half rings. The two half rings are connected and fixed to the push rod 4 by screws. The entire push rod 4 is made of metal material. When the push rod 4 is cast, two annular protrusions 7 are formed on the surface of the push rod 4. The annular protrusions 7 are located on both sides of the locking ring 6. Multiple threaded holes are opened on one side of the gearbox body 1. The threaded holes are evenly distributed around the round hole. The locking block 2 consists of upper and lower parts and is installed on the threaded holes by screws.

[0027] The cross-section of the two annular locking grooves 8 is a fan-shaped structure 17, and the vertical edges of the two fan-shaped structures 17 are all facing the middle annular locking groove 8. The length of the limiting post 10 is 40mm, and the depth of the annular locking groove 8 is 18mm.

[0028] The distance between the two annular locking grooves 8 is equal to the distance that the push rod 4 moves the paddle to one side. Both sides of the connecting groove 9 are provided with arc-shaped chamfers 16, and the arc-shaped chamfers 16 are asymmetrically arranged, with the radius of curvature on one side being half the radius of curvature on the other side.

[0029] Multiple positioning holes 21 are provided in the annular locking grooves 8 on both sides. The depth of the positioning holes 21 is less than half the radius of the roller 11. When the ball 14 moves to the apex position on both sides of the guide groove 12, the roller 11 enters the positioning hole 21.

[0030] In practical use, the push rod 4 is made of metal casting, and two annular protrusions 7 are formed on the surface of the push rod 4 during casting. The locking ring 6 is quickly installed by using the annular protrusions 7. The upper and lower halves of the locking ring 6 are inserted into the middle of the two annular protrusions 7. It should be noted that when inserting the locking ring 6, the limiting post 10 should be inserted into the sliding hole 18 first, and the second compression spring 19 should be inserted. The two halves of the ring are then fixed with screws. It should be noted that the two limiting posts 10 should be symmetrically arranged to avoid the gaps between the limiting posts 10 and the locking block 2 overlapping. The annular protrusions 7 not only limit the locking block 2, but also help the installer to install quickly.

[0031] After installing locking block 2, the lower half of locking block 2 is screwed onto the gearbox body 1, so that locking ring 6 is located in the middle annular locking groove 8, and sleeve 5 on one side slides in locking block 2. When the two parts are engaged, a certain gap will inevitably be generated, which will affect the rotation of roller 11. Therefore, when the two rollers 11 are in neutral, they are arranged vertically, and their rotation is limited to a specific angle to prevent rollers 11 from rotating to the gap position. Finally, the upper half of locking block 2 is placed on top of the lower half for final installation. After installing locking block 2, sleeve 5 is connected to the shift mechanism.

[0032] When shifting gears, the shifting mechanism pushes the sleeve 5 to one side. Since the guide groove 12 is S-shaped, the ball 14 rolls in the guide groove 12 as the sleeve 5 slides. However, the mounting ring 13 has a first compression spring 15 on both sides. When the sleeve 5 pushes the ball 14 a certain distance through the first compression spring 15, it will first push the push rod 4 to one side to perform the gear shifting operation, and drive the limit post 10 and the roller 11 on it to pass through the connecting groove 9 and enter the annular locking groove 8 on one side. When the push rod 4 can no longer move, the sleeve 5 will compress the first compression spring 15 and make the ball 14 roll in the guide groove 12. However, since the push rod 4 can no longer move, the push rod 4 will rotate at this time. By rotating, the limit post 10 swings away from the connecting groove 9 on one side, thereby locking the push rod 4.

[0033] This design allows the push rod 4 to move smoothly and accurately to the predetermined position during gear shifting. At the same time, the sleeve 5 returns to its original position under the action of the first compression spring 15, preparing for the next gear shift. After the sleeve 5 pushes the push rod 4 to move and engage the gear, the sleeve 5 continues to move and pushes the push rod 4 to rotate and lock, ensuring that the push rod 4 can be locked in a certain position after the gear engagement operation is completed. Through a simple structure, the push rod 4 can be effectively locked while ensuring that the gear engagement operation is quick and simple.

[0034] Both sides of the connecting groove 9 are provided with arc-shaped chamfers 16, and the arc-shaped chamfers 16 are asymmetrically arranged, with the radius of curvature on one side being half that of the other side. The limiting post 10 can smoothly slide from one annular locking groove 8 to another annular locking groove 8, reducing the jamming and resistance during gear shifting. The design of the arc-shaped chamfers 16 not only facilitates the entry and exit of the paddles, but also, the fact that the radius of curvature on one side of the arc-shaped chamfers 16 is half that of the other side allows the limiting post 10 to slide more smoothly in the annular locking grooves 8 on both sides during rotation, which reduces wear to a certain extent and extends the service life of the gearbox.

[0035] Because the diameter of the limiting post 10 is always smaller than the thickness of the annular locking groove 8, the limiting post 10 can smoothly enter the annular locking groove 8. The resulting gap will cause the limiting post 10 to wobble to a certain extent, which will cause the synchronizer sleeve to wobble. When the limiting post 10 slides into the annular locking groove 8, because the vertical side of the fan-shaped structure 17 faces the middle, the elastic force of the second compression spring 19 can make the limiting post 10 always push the roller 11 against the inner wall of the annular locking groove 8, which can effectively make the limiting post 10 against one side wall of the annular locking groove 8.

[0036] Furthermore, the depth of the annular locking groove 8 is b. When b is equal to half the overall length of the limiting post 10, the distance that the limiting post 10 penetrates into the annular locking groove 8 can withstand greater force and torque, making it less prone to breakage due to external force. However, at this time, the compressive force on the annular locking groove 8 is the same as the force on the protrusion of the push rod 4, which may cause some damage to the push rod 4. When b is less than half the overall length of the limiting post 10, the overall length of the limiting post 10 on the push rod 4 increases, the force-bearing area is increased, and the push rod 4 is prevented from being damaged, thus ensuring the driving stability and safety of the agricultural machinery.

[0037] The specific embodiment of the present invention has been described in detail above with reference to the accompanying drawings, but the present invention is not limited to the embodiments described above. For those skilled in the art, various changes, modifications, substitutions, and variations made to these embodiments without departing from the principles and ideas of the present invention should still fall within the protection scope of the present invention.

Claims

1. A walking drive gearbox for agricultural machinery, comprising a gearbox body (1), wherein a push rod (4) is connected to a paddle within the gearbox body (1), characterized in that, The gearbox body (1) has a circular hole, and the push rod (4) extends through the circular hole to the outside of the gearbox body (1). A locking block (2) is fixedly installed on one side of the gearbox body (1). A through hole (3) coaxially arranged with the circular hole is opened in the locking block (2). The push rod (4) extends into the through hole (3). A plurality of evenly arranged annular locking grooves (8) are opened in the locking block (2). The through hole (3) is coaxially arranged with the annular locking grooves (8) and passes through the annular locking grooves (8). A plurality of connecting grooves (9) are opened in the locking block (2). (9) Connect two adjacent annular locking grooves (8). Two symmetrically arranged limiting posts (10) are installed on the push rod (4). A placement groove (20) is opened at the end of the limiting post (10) away from the push rod (4). A roller (11) is rotatably connected in the placement groove (20). The roller (11) rolls in the annular locking groove (8). A push structure is installed on the push rod (4). When the gearbox switches gears, the push structure drives the limiting post (10) to enter the annular locking grooves (8) on both sides through the connecting groove (9) and rotate.

2. The agricultural machinery walking drive gearbox according to claim 1, characterized in that, The pushing structure includes a ball bearing (14), and an mounting ring (13) is fixedly installed on the pushing rod (4). The ball bearing (14) is slidably connected to the mounting ring (13). A sleeve (5) is slidably connected to the pushing rod (4). The sleeve (5) is slidably connected to the through hole (3). The mounting ring (13) is slidably connected to the sleeve (5). A guide groove (12) is provided on the sleeve (5). The guide groove (12) is S-shaped. The ball bearing (14) is slidably connected to the guide groove (12). A first compression spring (15) is abutted on both sides of the mounting ring (13). The other end of the first compression spring (15) on both sides abuts against the two ends of the sleeve (5). The first compression spring (15) is sleeved on the pushing rod (4). The sleeve (5) is connected to the shifting mechanism.

3. The agricultural machinery walking drive gearbox according to claim 2, characterized in that, A locking ring (6) is fixedly installed on the push rod (4). The locking ring (6) has multiple sliding holes (18). The limiting post (10) is slidably connected in the sliding hole (18). A second compression spring (19) is installed in the sliding hole (18). The two ends of the second compression spring (19) abut against the inner wall of the sliding hole (18) and the limiting post (10) respectively. The locking ring (6) and the mounting ring (13) are both divided into an upper half ring and a lower half ring. The two half rings are connected and fixed to the push rod (4) by screws.

4. The agricultural machinery walking drive gearbox according to claim 2, characterized in that, The cross-section of the annular locking groove (8) on both sides is a fan-shaped structure (17), and the vertical sides of the fan-shaped structure (17) on both sides are directed toward the annular locking groove (8) in the middle. The length of the limiting post (10) is a, and the depth of the annular locking groove (8) is b, 0 < b < 0.5a.

5. The agricultural machinery walking drive gearbox according to claim 4, characterized in that, The distance between the two annular locking grooves (8) is equal to the distance that the push rod (4) moves the paddle to one side. Both sides of the connecting groove (9) are provided with arc chamfers (16), and the arc chamfers (16) are asymmetrically arranged, with the radius of curvature on one side being half the radius of curvature on the other side.

6. The agricultural machinery walking drive gearbox according to claim 3, characterized in that, Multiple positioning holes (21) are provided in the annular locking grooves (8) on both sides. The depth of the positioning holes (21) is less than half the radius of the roller (11). When the ball (14) moves to the apex position on both sides of the guide groove (12), the roller (11) enters the positioning hole (21).

7. The agricultural machinery walking drive gearbox according to claim 3, characterized in that, The push rod (4) is made of metal material and two annular protrusions (7) are formed on the surface of the push rod (4) during the casting process. The annular protrusions (7) are located on both sides of the locking ring (6).

8. The agricultural machinery walking drive gearbox according to claim 3, characterized in that, The gearbox body (1) has multiple threaded holes on one side, which are evenly distributed around the circular hole. The locking block (2) consists of two parts, upper and lower, and is installed on the threaded holes by screws.

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