Transplanting mechanism plant spacing adjustment gearbox and plant spacing adjustment system

Abstract

The present invention discloses a plant spacing adjustment gearbox and a plant spacing adjustment system for a transplanting mechanism. The gearbox includes a box body, an input shaft, a plant spacing adjustment shaft, and an output shaft rotatably installed on the box body, and further includes a plant spacing adjustment assembly, a speed change shaft, and a speed change assembly; on the power transmission route, the speed change shaft is located between the input shaft and the plant spacing adjustment shaft, and the speed change assembly acts on the input shaft and the speed change shaft to switch the transmission speed ratio between the two between two fixed values, or cut off the power connection between the two. In the present invention, the user can select a suitable gear according to the output speed of the tractor that drives the transplanting machine to perform operations. In this way, the speed is consistent after the power is transmitted to the plant spacing adjustment shaft. The user can select the gear of the gear shift device according to the target plant spacing, which is convenient to operate; in addition, the power route can also be disconnected through the speed change assembly, so that the transplanting mechanism will not rotate idly after the transplanting machine travels to a position where no planting is required.

Description

Technical Field

[0001] The present invention relates to the technical field of agricultural machinery, and particularly to a plant spacing adjustment gearbox and a plant spacing adjustment system for a transplanting mechanism. Background Art

[0002] A transplanter is used for transplanting seedlings of rapeseed and vegetables. During the transplanting process, the plant spacing between seedlings is a very important indicator and often needs to be selected as required. Therefore, some transplanters are equipped with a gearbox to facilitate the adjustment of the plant spacing.

[0003] Patent CN209909122U provides a working transmission device for a transplanter, which has a gear position transmission assembly and a gear position selection transmission assembly. Through the gear position selection transmission assembly, the gear position transmission assembly can be meshed and selected with the forward gear position gear or the reverse gear position gear. When the gear position transmission assembly is not meshed with both, the transplanter is in the neutral position; in addition, the patent also includes a plant spacing control unit, which includes a plant spacing power shaft that transmits power outward. At least three linked plant spacing control gears are sequentially sleeved on the plant spacing power shaft, and the number of teeth and the pitch circle diameter of each plant spacing control gear are set differently. By selecting different plant spacing control gears to mesh with the gear position transmission assembly, the adjustment of the plant spacing during planting is realized.

[0004] The above patent has two technical problems: First, the transplanter is towed by a tractor to perform operations, and the operating power is provided by the power output shaft of the tractor. The output speeds of existing tractors are different (generally there are two types: 540 r / min and 720 r / min). When the transplanter is docked with different tractors, the power input to the input shaft is different, which will cause the preset plant spacing to be different from the actual planted plant spacing. To solve this problem, generally, an external speed change mechanism needs to be set up, resulting in a bloated system and complex operation, or the user needs to set the corresponding relationship between two gear positions and plant spacings according to the tractor output speed, which will increase the learning cost and is prone to errors; Second, the patent realizes the control of the plant spacing by controlling at least three linked plant spacing control gears to mesh with the gear position transmission assembly. It is relatively complex to control the meshing and disengagement of three or more gears on one side by using a mechanical structure, which will increase the cost and failure rate.

[0005] The following embodiments will be expanded with the above-mentioned first technical problem as the main technical problem. Summary of the Invention

[0006] Object of the Invention: In order to overcome the deficiencies in the prior art, the present invention provides a plant spacing adjustment gearbox and a plant spacing adjustment system for a transplanting mechanism that can adapt to tractors with different output speeds.

[0007] Technical solution: To achieve the above object, the plant spacing adjustment gearbox of the transplanting mechanism of the present invention includes a box body, an input shaft, a plant spacing adjustment shaft, and an output shaft rotatably installed on the box body. It further includes a plant spacing adjustment component for changing the transmission speed ratio between the plant spacing adjustment shaft and the output shaft. The plant spacing adjustment component includes a gear shift device and multiple sets of variable speed gear sets with different transmission ratios. Only one set of the variable speed gear sets is in a working state at the same time;

[0008] It further includes a variable speed shaft and a variable speed component; on the power transmission route, the variable speed shaft is located between the input shaft and the plant spacing adjustment shaft, and the variable speed component acts on both the input shaft and the variable speed shaft to switch the transmission speed ratio between two fixed values or cut off the power connection between the two.

[0009] The variable speed component includes a first gear and a second gear fixed on the input shaft, a third gear and a fourth gear slidably installed on the variable speed shaft, and a gear shifting mechanism;

[0010] The third gear and the fourth gear are relatively fixed, and the two are driven by the gear shifting mechanism to switch between three gear states, which are respectively:

[0011] Neutral gear: At this time, both the first gear and the second gear are located between the third gear and the fourth gear;

[0012] First gear: At this time, the first gear meshes with the third gear;

[0013] Second gear: At this time, the second gear meshes with the fourth gear.

[0014] Further, the gear shifting mechanism includes a shift fork connecting the third gear, a sliding shaft connecting the shift fork, and a gear position holding mechanism for maintaining the axial position of the sliding shaft.

[0015] Further, the sliding shaft has three arc-shaped grooves corresponding to the three gears; the gear position holding mechanism includes a steel ball and a spring installed in the box body, and the spring keeps the steel ball in contact with the sliding shaft and has a tendency to move closer to the axis of the sliding shaft.

[0016] Further, the variable speed shaft has a spline portion, and both the third gear and the fourth gear have spline holes.

[0017] Further, each set of the variable speed gear sets includes a first variable speed gear installed on the plant spacing adjustment shaft; the first variable speed gear has a central hole, and a plurality of arc-shaped grooves arranged in a circumferential array are formed on the hole wall of the central hole;

[0018] A set of engaging ball groups for establishing the power transmission relationship between the plant spacing adjustment shaft and the first transmission gear is provided on the plant spacing adjustment shaft corresponding to each of the first transmission gears. Only one set of engaging ball groups engages its corresponding first transmission gear with the plant spacing adjustment shaft at the same time.

[0019] Further, the plant spacing adjustment assembly further includes a transition shaft rotatably installed on the box body. Each set of transmission gear groups includes a second transmission gear that meshes with the first transmission gear and is fixed on the transition shaft; a transmission gear group is provided between the transition shaft and the output shaft.

[0020] A plant spacing adjustment system for a transplanting mechanism includes the above-mentioned plant spacing adjustment gearbox for the transplanting mechanism, and further includes a first operating mechanism connected to the sliding shaft and a second operating mechanism connected to the gear shifting device;

[0021] The first operating mechanism includes a first operating handle, a transition rod, and a rotating frame; the first operating handle and the rotating frame are respectively rotatably installed on the seat body and the box body; both ends of the transition rod are respectively connected to the first operating handle and the rotating frame;

[0022] The end of the sliding shaft has a ring groove portion, and the rotating frame has a placing portion placed in the ring groove portion.

[0023] Further, the gear shifting device has a shifting rod slidably installed axially relative to the plant spacing adjustment shaft; the second operating mechanism includes a pin shaft fixed on the shifting rod and a second operating rod rotatably installed on the seat body; a slot is provided at the end of the second operating rod, and the pin shaft passes through the slot.

[0024] Beneficial effects: The plant spacing adjustment gearbox and the plant spacing adjustment system of the transplanting mechanism of the present invention, by arranging a transmission shaft and a transmission component in the box body, the user can select a suitable gear according to the model of the tractor that pulls the transplanting machine to perform operations. In this way, the rotational speed is the same after the power is transmitted to the plant spacing adjustment shaft. The user can select the gear of the gear shifting device according to the target plant spacing, which is convenient to operate, does not require additional connection of a transmission device, and does not increase the operation difficulty; in addition, the power transmission route can be disconnected through the transmission component to stop the movement of the transplanting mechanism, so that after the transplanting machine travels to a position where no planting is required, the transplanting mechanism will not rotate idly. Description of the Drawings

[0025] Figure 1 It is an external view of the plant spacing adjustment gearbox for the transplanting mechanism;

[0026] Figure 2 It is a first perspective structure diagram inside the plant spacing adjustment gearbox for the transplanting mechanism;

[0027] Figure 3It is the second perspective structure diagram inside the plant spacing adjustment gearbox of the transplanting mechanism;

[0028] Figure 4 It is Figure 2 The enlarged structure diagram of part A in

[0029] Figure 5 It is the combined structure diagram of the sliding shaft and its peripheral components;

[0030] Figure 6 It is the combined structure diagram of the plant spacing adjustment shaft and its peripheral components;

[0031] Figure 7 It is the structure diagram of the first speed gear;

[0032] Figure 8 It is the structure diagram of the shift lever;

[0033] Figure 9 It is the structure diagram of the plant spacing adjustment system of the transplanting mechanism;

[0034] Figure 10 It is Figure 9 The enlarged structure diagram of part B in

[0035] Figure 11 It is Figure 9 The enlarged structure diagram of part C in

[0036] Figure 12 It is the combined diagram of the plant spacing adjustment shaft and the elastic retaining ring;

[0037] Figure 13 It is the structure diagram of the elastic retaining ring.

[0038] In the figure: 1 - housing; 2 - input shaft; 3 - plant spacing adjustment shaft; 31 - radial hole; 32 - axial hole; 33 - annular accommodating groove; 34 - communication groove; 35 - elastic retaining ring; 351 - annular part; 352 - retaining part; 4 - output shaft; 5 - plant spacing adjustment assembly; 51 - first speed gear; 511 - central hole; 512 - arc groove; 52 - engaging ball; 53 - shift lever; 54 - extruded part; 541 - arc-shaped annular groove; 55 - transition shaft; 56 - second speed gear; 57 - transmission gear set; 58 - retaining device; 6 - speed shaft; 61 - spline part; 7 - speed change assembly; 71 - first gear; 72 - second gear; 73 - third gear; 74 - fourth gear; 75 - fork; 76 - sliding shaft; 761 - arc-shaped groove; 762 - annular groove part; 77 - gear position retaining mechanism; 771 - steel ball; 772 - spring; 8 - first operating mechanism; 81 - first operating handle; 82 - transition rod; 9 - second operating mechanism; 91 - pin shaft; 92 - second operating lever; 10 - seat body. Detailed implementation manners

[0039] The present invention will be further described below in conjunction with the accompanying drawings.

[0040] As shown in Figures 1-3 the transplanting mechanism plant spacing adjustment gearbox (hereinafter referred to as: gearbox), which includes a box body 1 and an input shaft 2, a plant spacing adjustment shaft 3, and an output shaft 4 rotatably installed on the box body. The gearbox further includes a plant spacing adjustment assembly 5 for changing the transmission speed ratio between the plant spacing adjustment shaft 3 and the output shaft 4. The plant spacing adjustment assembly 5 includes a gear shift device and multiple sets of variable speed gear sets with different transmission ratios. Only one set of the variable speed gear sets is in the working state at the same time. In this way, by making different sets of variable speed gear sets in the working state, the rotation speed of the output shaft 4 can be adjusted, and the adjustment of the plant spacing can be realized.

[0041] In order to solve the influence of the input rotation speed of different tractors on the plant spacing adjustment shaft 3, the gearbox further includes a variable speed shaft 6 and a variable speed assembly 7; in the power transmission route, the variable speed shaft 6 is located between the input shaft 2 and the plant spacing adjustment shaft 3, and the variable speed assembly 7 acts on the input shaft 2 and the variable speed shaft 6 to switch the transmission speed ratio between two different fixed values, or cut off the power connection between the two. After the transplanting machine is connected to the tractor, the user can switch the transmission speed ratio through the variable speed assembly 7 according to the rotation speed of the tractor power output shaft, so that the transmission speed ratio is adapted to the rotation speed of the tractor power output shaft. In this way, no matter whether the tractor with an output rotation speed of 540 r / min or 720 r / min drives the transplanting machine to perform operations, after the power is transmitted to the plant spacing adjustment shaft 3 through the variable speed shaft 6, the rotation speed of the plant spacing adjustment shaft 3 is relatively consistent. The user can select the gear of the gear shift device according to the target plant spacing, which is convenient to operate, does not require additional connection of a variable speed device, and does not increase the operation difficulty; in addition, the power route can also be disconnected through the variable speed assembly to stop the movement of the transplanting mechanism, so that after the transplanting machine travels to a position where no planting is required, the transplanting mechanism will not rotate idly.

[0042] Specifically, as shown in Figure 2 the variable speed assembly 7 includes a first gear 71 and a second gear 72 fixed on the input shaft 2, a third gear 73 and a fourth gear 74 slidably installed on the variable speed shaft 6, and a shift mechanism.

[0043] The third gear 73 and the fourth gear 74 are relatively fixed. They can be integrally formed or processed separately and then fixed together. And these two gears are driven by the shifting mechanism to switch between three gear states, which are respectively: (1) Neutral gear: At this time, both the first gear 71 and the second gear 72 are located between the third gear 73 and the fourth gear 74; (2) First gear: At this time, the first gear 71 meshes with the third gear 73, and the second gear 72 disengages from the fourth gear 74; (3) Second gear: At this time, the second gear 72 meshes with the fourth gear 74.

[0044] In this embodiment, the number of teeth of the first gear 71 is less than that of the second gear 72. Correspondingly, the transmission speed ratio between the input shaft 2 and the transmission shaft 6 in the first gear (3:4 in this embodiment) is smaller than the transmission speed ratio between the input shaft 2 and the transmission shaft 6 in the second gear (1:1 in this embodiment). When the output speed of the tractor is 540 r / min, it is switched to the second gear. When the output speed of the tractor is 720 r / min, it is switched to the first gear, so that the rotation speed of the plant spacing adjusting shaft 3 is consistent.

[0045] The shifting mechanism includes a fork 75 connected to the third gear 73, a sliding shaft 76 connected to the fork 75, and a gear position holding mechanism 77 for maintaining the axial position of the sliding shaft 76. There are three arc-shaped grooves 761 corresponding to the three gears on the sliding shaft 76; as Figure 5 shown, the gear position holding mechanism 77 includes a steel ball 771 and a spring 772 installed in the box body 1. The spring 772 keeps the steel ball 771 in contact with the sliding shaft 76 and has a tendency to move closer to the axis of the sliding shaft 76.

[0046] With the above structure, when the third gear 73 is in a certain gear, the steel ball 771 is placed in the arc-shaped groove 761 corresponding to this gear and keeps the sliding shaft 76 in this position. When shifting gears is required, an axial force exceeding a certain value is applied to the sliding shaft 76 to squeeze the steel ball 771 out of the current arc-shaped groove 761. After the shifting is completed, the steel ball 771 enters another arc-shaped groove 761 and then keeps the sliding shaft 76 in the current position.

[0047] There is a spline portion 61 on the transmission shaft 6, and there are spline holes in both the third gear 73 and the fourth gear 74, so that the sliding between the gear and the transmission shaft 6 is smooth and the force is evenly distributed.

[0048] In order to achieve smooth gear shifting, the teeth on the first gear 71, the second gear 72, the third gear 73 and the fourth gear 74 all have a pointed corner on one side. In the above-mentioned neutral gear state, the first pointed corner d on the first gear 71 and the third pointed corner e on the third gear 73 are arranged oppositely (as Figure 4As shown, the second pointed corner portion on the second gear 72 is arranged opposite to the fourth pointed corner portion on the fourth gear 74. In this way, when shifting gears, the pointed corner portions of the two gears to be engaged come into contact first. The guiding function of the pointed corner portions can correct the positions of the two gears relative to each other, enabling the two gears to mesh smoothly.

[0049] In the above plant spacing adjusting assembly 5, there are a total of three speed change gear sets. Each speed change gear set includes a first speed change gear 51 mounted on the plant spacing adjusting shaft 3. As Figure 3 shown, the labels of the first speed change gears on the three speed change gear sets are 51a, 51b, and 51c respectively; as Figure 7 shown, the first speed change gear 51 has a central hole 511, and a plurality of arc grooves 512 arranged in a circumferential array are formed on the hole wall of the central hole 511;

[0050] As Figure 6 shown, a set of engagement ball groups is provided on the plant spacing adjusting shaft 3 corresponding to each first speed change gear 51. The engagement ball group includes a plurality of engagement balls 52 arranged in a circumferential array. Radial holes 31 corresponding to each engagement ball 52 are formed on the plant spacing adjusting shaft 3. Each engagement ball 52 can move in the radial direction of the plant spacing adjusting shaft 3; axial holes 32 communicating with each radial hole are also formed on the plant spacing adjusting shaft 3.

[0051] The gear shifting device includes a gear shift lever 53 and an extrusion member 54. The gear shift lever 53 is coaxially mounted with the plant spacing adjusting shaft 3 and can slide along the axial hole. The extrusion member 54 is fixed to the end of the gear shift lever 53. When the extrusion member 54 acts on the engagement ball group, the corresponding first speed change gear 51 of the engagement ball group rotates with the plant spacing adjusting shaft 3. As Figure 8 shown, an arc-shaped ring groove 541 is provided on the periphery of the extrusion member 54.

[0052] The plant spacing adjusting assembly 5 further includes a transition shaft 55 rotatably mounted on the housing 1. Each speed change gear set includes a second speed change gear 56 that meshes with the first speed change gear 51 and is fixed to the transition shaft 55; a transmission gear set 57 is provided between the transition shaft 55 and the output shaft 4.

[0053] With the structure of the plant spacing adjustment component 5 described above, by pulling the shift lever 53 to move axially along the plant spacing adjustment shaft 3, the engaging balls 52 of different engaging ball groups can be pushed out, so that a part of the engaging ball 52 protrudes outside the plant spacing adjustment shaft 3 and is embedded in the arc groove 512 of the corresponding first transmission gear 51. In this way, the first transmission gear 51 can move along with the plant spacing adjustment shaft 3 and transmit the power of the plant spacing adjustment shaft 3 to the intermediate shaft 55 and the output shaft 4. The engaging ball 52 acted on by the extruding member 54 contacts the arc-shaped annular groove 541, and when the gearbox operates, the engaging ball 52 moves along the arc-shaped annular groove 541. In the above structure, the two gears included in each transmission gear group are always in a meshing state. Which transmission gear group is in the working state is determined by the extruding member 54 extruding the engaging ball 52. Compared with the scheme of axially sliding meshing or disengaging of the driving gear, the structure is simpler, more compact, and easier to control, and can solve the second technical problem proposed in the background art.

[0054] In this embodiment, as Figure 12 shown, two radial holes 31 are provided on the plant spacing adjustment shaft 3 corresponding to each first transmission gear 51, and the radial holes 31 corresponding to adjacent first transmission gears 51 are staggered in the circumferential direction of the plant spacing adjustment shaft 3. An annular accommodating groove 33 is formed on the plant spacing adjustment shaft 3 between two groups of engaging ball groups, and a communication groove 34 is provided between the annular accommodating groove 33 and the radial holes 31 on both sides thereof; an elastic retaining ring 35 is installed on the plant spacing adjustment shaft 3. As Figure 13 shown, the elastic retaining ring 35 is composed of an annular portion 351 and a retaining portion 352 deviating from the annular portion 351. The retaining portion 352 is U-shaped, and the elastic retaining ring 35 is integrally formed with the annular portion 351. The deviating directions of adjacent two retaining portions 352 with respect to the annular portion 351 are opposite. The annular portion 351 is embedded in the annular accommodating groove 33, and the retaining portion 352 extends into the radial hole 31 on the side of the annular accommodating groove 33 through the communication groove 34. Due to the elasticity of the elastic retaining ring 35, it can be sleeved on the plant spacing adjustment shaft 3 and installed in place by deforming it. With the above structure, when the extruding member 54 acts on the engaging ball 52, the retaining portion 352 acts on the side of the engaging ball 52. When the extruding member 54 contacts and acts on the engaging ball 52, the elasticity of the retaining portion 352 causes the engaging ball 52 to return to the radial hole 31 and be in a non-protruding state. In this way, when the plant spacing adjustment shaft 3 rotates, it can be prevented that the engaging ball 52 is thrown out and engages with the corresponding first transmission gear 51, resulting in two or more groups of engaging balls 52 engaging with the corresponding first transmission gears 51 at the same time, causing system failures or damages. In addition, one elastic retaining ring 35 can act on two groups of engaging balls, which can save the number of elastic retaining rings 35.

[0055] A holding device 58 acting on the shift lever 53 is installed on the box body 1. The structures of the holding device 58 and the arc-shaped groove on the shift lever 53 that cooperates with the holding device 58 are partially consistent with those of the above-mentioned gear holding mechanism 77, and will not be elaborated here.

[0056] The present invention also provides a plant spacing adjustment system for a transplanting mechanism, as Figure 9 shown, which includes the above-mentioned plant spacing adjustment gearbox of the transplanting mechanism, and also includes a first operating mechanism 8 connected to the sliding shaft 76 and a second operating mechanism 9 connected to the gear shifting device.

[0057] As Figure 10 shown, the first operating mechanism 8 includes a first operating handle 81, a transition rod 82, and a rotating frame 83; the first operating handle 81 and the rotating frame 83 are respectively rotatably installed on the seat body 10 and the box body 1; the transition rod 82 has two ends, the axes of the two ends are perpendicular to each other, and the two ends are respectively connected to the first operating handle 81 and the rotating frame 83; the rotating frame 83 has a placing portion 831 placed in the annular groove portion 762.

[0058] In actual use, the above-mentioned gearbox is installed under the driver's seat, and the first operating handle 81 is vertically installed on the side of the seat. Since the two ends of the transition rod 82 are perpendicular to each other, the vertically placed first operating handle 81 can control the movement of the shaft 76, which is convenient for users to operate.

[0059] As Figure 11 shown, the second operating mechanism 9 includes a pin shaft 91 fixed on the shift lever 53 and a second operating lever 92 rotatably installed on the seat body 10; the end of the second operating lever 92 has a slotted hole, and the pin shaft 91 passes through the slotted hole. By rotating the second operating lever 92, the shift lever 53 can be driven to move to achieve plant spacing adjustment.

[0060] The above are only the preferred embodiments of the present invention. It should be noted that: for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and refinements can be made, and these improvements and refinements should also be regarded as the protection scope of the present invention.

Claims

1. Plant spacing adjustment gearbox of the transplanting mechanism, which includes a box body (1), an input shaft (2), a plant spacing adjustment shaft (3), and an output shaft (4) rotatably installed on the box body. It also includes a plant spacing adjustment component (5) for changing the transmission speed ratio between the plant spacing adjustment shaft (3) and the output shaft (4). The plant spacing adjustment component (5) includes a gear shift device and multiple variable speed gear sets with different transmission ratios. Only one group of the variable speed gear sets is in the working state at the same time. It is characterized in that: It also includes a variable speed shaft (6) and a variable speed component (7); on the power transmission route, the variable speed shaft (6) is located between the input shaft (2) and the plant spacing adjustment shaft (3), and the variable speed component (7) acts on the input shaft (2) and the variable speed shaft (6) to switch the transmission speed ratio between two fixed values or cut off the power connection between the two. The variable speed component (7) includes a first gear (71) and a second gear (72) fixed on the input shaft (2), a third gear (73) and a fourth gear (74) slidably installed on the variable speed shaft (6), and a gear shift mechanism. The third gear (73) and the fourth gear (74) are relatively fixed, and the two are driven by the gear shift mechanism to switch between three gear states, which are respectively: Neutral: At this time, both the first gear (71) and the second gear (72) are located between the third gear (73) and the fourth gear (74). First gear: At this time, the first gear (71) meshes with the third gear (73). Second gear: At this time, the second gear (72) meshes with the fourth gear (74). The transmission speed ratio between the input shaft (2) and the variable speed shaft (6) in the first gear is 3:4; the transmission speed ratio between the input shaft (2) and the variable speed shaft (6) in the second gear is 1:1; when the tractor output speed is 540 r / min, switch to the second gear, and when the tractor output speed is 720 r / min, switch to the first gear. Each group of the variable speed gear sets includes a first variable speed gear (51) installed on the plant spacing adjustment shaft (3); the first variable speed gear (51) has a central hole (511), and a plurality of arc grooves (512) arranged in a circumferential array are formed on the inner wall of the central hole (511). A set of engagement ball groups is arranged on the plant spacing adjustment shaft (3) corresponding to each first variable speed gear (51). The engagement ball group includes a plurality of engagement balls (52) arranged in a circumferential array, and each engagement ball (52) can move in the radial direction of the plant spacing adjustment shaft (3). The gear shift device includes a gear shift lever (53) and an extrusion part (54). The gear shift lever (53) is slidably arranged in the center of the plant spacing adjustment shaft (3), and the extrusion part (54) is fixed at the end of the gear shift lever (53). When the extrusion part (54) acts on the engagement ball group, the corresponding first variable speed gear (51) of the engagement ball group rotates along with the plant spacing adjustment shaft (3). Two radial holes (31) are provided on the plant spacing adjustment shaft (3) corresponding to each first speed change gear (51), and the radial holes (31) corresponding to adjacent first speed change gears (51) are staggered in the circumferential direction of the plant spacing adjustment shaft (3); an annular placement groove (33) is formed on the plant spacing adjustment shaft (3) between two sets of engaging ball groups, and a communication groove (34) is provided between the annular placement groove (33) and the radial holes (31) on both sides thereof; an elastic retaining ring (35) is installed on the plant spacing adjustment shaft (3), and the elastic retaining ring (35) is composed of an annular portion (351) and a retaining portion (352) deviating from the annular portion (351), the retaining portion (352) is U-shaped, and the elastic retaining ring (35) is integrally formed with the annular portion (351), and the deviation directions of adjacent two retaining portions (352) with respect to the annular portion (351) are opposite. The annular portion (351) is embedded in the annular placement groove (33), and the retaining portion (352) extends into the radial hole (31) on the side of the annular placement groove (33) through the communication groove (34); when the extruding member (54) acts on the engaging ball (52), the retaining portion (352) acts on the side of the engaging ball (52), and when the extruding member (54) contacts and acts on the engaging ball (52), the elasticity of the retaining portion (352) causes the engaging ball (52) to return to the radial hole (31) and be in a non-protruding state.

2. The plant spacing adjustment gearbox of the transplanting mechanism according to claim 1, characterized in that, The shifting mechanism includes a fork (75) connecting the third gear (73), a sliding shaft (76) connecting the fork (75), and a gear position retaining mechanism (77) for maintaining the axial position of the sliding shaft (76).

3. The plant spacing adjusting gearbox of the transplanting mechanism according to claim 2, characterized in that, Three arc-shaped grooves (761) corresponding to three gear positions are provided on the sliding shaft (76); the gear position retaining mechanism (77) includes a steel ball (771) and a spring (772) installed in the box body (1), and the spring (772) keeps the steel ball (771) in contact with the sliding shaft (76) and has a tendency to move closer to the axis of the sliding shaft (76).

4. The plant spacing adjustment gearbox of the transplanting mechanism according to claim 1, characterized in that, A spline portion (61) is provided on the speed change shaft (6), and spline holes are provided in both the third gear (73) and the fourth gear (74).

5. The plant spacing adjustment gearbox of the transplanting mechanism according to claim 1, characterized in that, The plant spacing adjustment assembly (5) further includes a transition shaft (55) rotatably installed on the box body (1), and each set of speed change gear groups includes a second speed change gear (56) meshing with the first speed change gear (51) and fixed on the transition shaft (55); a transmission gear group (57) is provided between the transition shaft (55) and the output shaft (4).

6. The plant spacing adjustment gearbox of the transplanting mechanism according to claim 1, characterized in that, An arc-shaped ring groove (541) is provided on the periphery of the extruding member (54).

7. Transplanting mechanism plant spacing adjustment system, characterized in that, It includes the plant spacing adjustment gearbox of the transplanting mechanism described in claim 3, and further includes a first operating mechanism (8) connecting the sliding shaft (76) and a second operating mechanism (9) connecting the gear position switching device; The first operating mechanism (8) includes a first operating handle (81), a transition rod (82), and a rotating frame (83); the first operating handle (81) and the rotating frame (83) are respectively rotatably mounted on the seat body and the box body (1); both ends of the transition rod (82) are respectively connected to the first operating handle (81) and the rotating frame (83). The end of the sliding shaft (76) has an annular groove portion (762), and the rotating frame (83) has a placing portion (831) placed in the annular groove portion (762).

8. The plant spacing adjustment system of the transplanting mechanism according to claim 7, characterized in that, The gear shifting device has a shifting rod (53) axially slidably mounted relative to the plant spacing adjusting shaft (3); the second operating mechanism (9) includes a pin shaft (91) fixed on the shifting rod (53) and a second operating rod (92) rotatably mounted on the seat body; the end of the second operating rod (92) has a slotted hole, and the pin shaft (91) passes through the slotted hole.

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