Downward pressure automatic adjusting device and seeding monomer

Abstract

The invention discloses an automatic downward pressure adjusting device and a seeding monomer, and belongs to the technical field of agricultural seeding. The downward pressure automatic adjusting device comprises a parallel four-connecting-rod profiling mechanism, an electric adjusting mechanism and a sensing control system. The parallel four-connecting-rod profiling mechanism comprises a front plate, an upper rod and a lower rod; in the electric adjusting mechanism, the top of a shell is rotationally connected with a middle shaft fixed between the middle rear sections of two upper rods, the rear ends of two driven rods are rotationally connected to the two sides of the middle of the shell correspondingly, and the front ends of the driven rods are rotationally connected to the connecting positions of the upper rods and the front plate. The front end and the rear end of the fixing rod are fixedly connected to the middle of the top end of the front plate and the top end of the arc-shaped rail respectively. The sensing control system comprises an angle sensor and a controller, the controller controls the electric push-pull rod to work, and the electric push-pull rod rotates along with the parallel four-connecting-rod profiling mechanism to automatically adjust the downward pressure of the seeding single body in real time.

Description

Technical Field

[0001] The present invention belongs to the technical field of agricultural seeding, and more specifically, relates to a downforce automatic adjustment device and a seeding unit. Background Art

[0002] Mechanized seeding plays a crucial role in improving crop yield and per unit yield. The stability and consistency of seeding depth directly affect seed germination and the uniformity of seedling emergence. The stability and consistency of seeding depth are also important indicators for evaluating seeding quality.

[0003] During seeding operations, both the hardness of the soil and the surface undulations have a great impact on seeding depth. Hard soil or the upward pull caused by the decomposition of traction force will result in insufficient downforce of the seeding unit, too shallow seeding depth, which is not conducive to seed germination and weak seedling emergence, and thus leads to yield reduction; soft soil or the downward pressure caused by the decomposition of traction force will result in excessive downforce of the seeding unit, too deep seeding depth, which is not conducive to seedling emergence and causes yield reduction. Inconsistent seeding depth will affect the density and uniformity of crops, making the crops receive different temperatures, lights, etc., and affecting crop yield.

[0004] Therefore, it is necessary to provide an adjustment device that can ensure the stability and consistency of seeding depth. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a downforce automatic adjustment device and a seeding unit to achieve the follow-up adjustment of the downforce of the seeding unit.

[0006] To solve the above technical problems, according to one aspect of the present invention, a downforce automatic adjustment device is provided, which includes a parallel four-bar linkage profiling mechanism, an electric adjustment mechanism, and a sensing control system; The parallel four-bar linkage profiling mechanism includes a front plate, upper rods, and lower rods. Two upper rods form a group, and two lower rods form a group; The front end and the rear end of the upper rod are respectively rotatably connected to the top of the front plate and the upper part of the unit frame; the front end and the rear end of the lower rod are respectively rotatably connected to the bottom of the front plate and the lower part of the unit frame; The electric adjustment mechanism includes a driven rod, a fixed rod, an intermediate shaft, an electric push-pull rod, an arc track, a first roller, and a second roller; The electric push-pull rod includes a housing and a push-pull rod. The intermediate shaft is fixed between the middle and rear sections of the two upper rods, and the top of the housing is rotatably connected to the intermediate shaft; Two driven rods form a group. The rear ends of the two driven rods are respectively rotatably connected to both sides of the middle of the housing, and the front ends of the two driven rods are respectively rotatably connected to the connection part between the upper rod and the front plate; The front end of the fixed rod is fixedly connected to the middle of the top of the front plate, the rear end of the fixed rod is fixedly connected to the top of the arc track, and the bottom end of the arc track is fixedly connected to the middle of the bottom of the front plate; The first roller and the second roller are both directly or indirectly connected to the push-pull rod and are respectively arranged on the upper and lower sides of the arc track. The sensing control system includes an angle sensor and a controller. The controller is respectively connected to the angle sensor and the electric push-pull rod. The angle sensor is used to collect the change information of the traction angle and transmit it to the controller, and the controller controls the operation of the electric push-pull rod.

[0007] Furthermore, the sensing control system includes an optical sensor, which is connected to the controller and is used to collect the water content of the soil.

[0008] Furthermore, a first sleeve is fixed on the upper part of the single body frame. The rear ends of the two upper rods are connected by a bolt, and the bolt passes through the first sleeve. A second sleeve is fixed on the lower part of the single body frame. The rear ends of the two lower rods are connected by a bolt, and the bolt passes through the second sleeve.

[0009] Furthermore, the angle sensor includes an angle sensor fixed disk and an angle sensor moving disk. The angle sensor fixed disk is installed at one end of the second sleeve, and the angle sensor moving disk is installed at the rear end of the lower rod corresponding to the angle sensor fixed disk.

[0010] Furthermore, the first roller is installed on the first roller shaft, the second roller is installed on the second roller shaft, and the ends of the first roller shaft and the second roller shaft are connected by a connecting plate. The first roller shaft is connected to the bottom of the push-pull rod.

[0011] According to another aspect of the present invention, a seeding unit is provided, which includes a seed metering system, a double-disc opener, a depth-limiting mechanism, a pressing device, a seeding depth adjusting device, and the downforce automatic adjusting device described above.

[0012] Furthermore, the seed metering system includes a seed box, a seed metering device, and a seed metering pipe. The seed metering device is fixedly installed on the single body frame, the seed box is fixed above the seed metering device, the bottom of the seed metering device is connected to the seed metering pipe, and the bottom of the seed metering pipe is located inside the double-disc opener.

[0013] Furthermore, the double-disc opener is arranged below the single body frame and is installed on the single body frame through a disc shaft.

[0014] Further, the depth-limiting mechanism is arranged behind the double-disc furrow opener and includes depth-limiting wheels, wheel arms, wheel axles, limit blocks, limit block axles and downward pressure sensors. The two depth-limiting wheels are respectively located at the rear outside of the double-disc furrow opener. The depth-limiting wheels are connected to the single-frame through the wheel arms. One end of the wheel arm is connected to the depth-limiting wheel, and the other end of the wheel arm is connected to the single-frame through the wheel axle. The limit block axle is installed on the single-frame above the wheel arm. The limit block is provided with a middle hole, and the middle hole of the limit block passes through the limit block axle. The downward pressure sensor is installed at the lower end of the limit block axle and within the middle hole of the limit block. The limit block axle is connected to the seeding depth adjustment device. The seeding depth adjustment device is installed behind the single-frame and adjusts the seeding depth by adjusting the position of the limit block axle.

[0015] Further, the pressing device is arranged behind the seeding unit and is connected to the single-frame through a shaft.

[0016] By using the device of the present invention, during the seeding operation process, according to the angle change information collected by the angle sensor, and through the electric adjustment mechanism, the downward pressure of the seeding unit is automatically adjusted in real time as the parallel four-bar linkage profiling mechanism rotates, realizing the follow-up adjustment of the downward pressure of the seeding unit, ensuring the consistency and stability of the seeding depth, and further improving the seed germination rate, seeding operation quality and crop yield.

[0017] The present invention collects information on the soil moisture content through an optical sensor and determines the set value range of the downward pressure of the seeding unit according to the collected information. During the seeding operation process, when the soil moisture content changes, the set value range of the downward pressure of the seeding unit also changes accordingly to ensure the optimal set value of the downward pressure of the seeding unit.

[0018] The present invention uses the downward pressure sensor to sense the actual magnitude of the downward pressure in real time. When the actual downward pressure exceeds the set value range, the electric adjustment mechanism performs timely auxiliary adjustment during the follow-up adjustment process to ensure the accuracy of the downward pressure of the seeding unit. Description of the Drawings

[0019] The drawings here are used to provide further illustration of the present invention and constitute a part of this application. The schematic embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention.

[0020] Figure 1 is the overall structural schematic diagram of the seeding unit of the present invention; Figure 2 is the structural schematic diagram of the parallel four-bar linkage profiling mechanism; Figure 3 is the structural schematic diagram of the electric adjustment mechanism; Figure 4 is the installation schematic diagram of the angle sensor diagram; Figure 5 is the connection schematic diagram of the roller; Figure 6 is a schematic structural diagram of a seed metering system; Figure 7 is a schematic structural diagram of a double-disc furrow opener and a depth-limiting mechanism. To avoid obscuring the double-disc furrow opener, Figure 7 the outer depth-limiting wheels are omitted in the figure.

[0021] In the figure, 1 - parallelogram linkage profiling mechanism, 2 - electric adjustment mechanism, 3 - single-body frame, 4 - angle sensor, 5 - controller, 6 - optical sensor, 7 - seed metering system, 8 - double-disc furrow opener, 9 - depth-limiting mechanism, 10 - pressing device, 11 - seeding depth adjustment device; 100 - front plate, 110 - upper rod, 120 - lower rod; 130 - first sleeve, 140 - second sleeve, 150 - connecting pipe; 200 - driven rod, 210 - fixed rod, 220 - intermediate shaft, 230 - electric push-pull rod, 240 - arc track, 250 - first roller, 260 - second roller, 270 - connecting plate, 280 - first roller shaft, 290 - second roller shaft, 231 - housing, 232 - push-pull rod; 400 - angle sensor fixed disk, 410 - angle sensor moving disk; 700 - seed box, 710 - seed metering device, 720 - seed metering pipe; 810 - disk shaft; 910 - depth-limiting wheel, 920 - wheel arm, 930 - limit block, 940 - limit block shaft, 950 - lower pressure sensor, 960 - wheel shaft. Detailed implementation manners

[0022] To enable those skilled in the art to better understand the present invention, the present invention will be further clearly and completely described below with reference to the accompanying drawings and in conjunction with embodiments. It should be noted that, without conflict, the implementation manners and features in the embodiments in the present application can be combined with each other.

[0023] As Figure 1 shown, a down-force automatic adjustment device provided by a typical implementation manner of the present invention includes a parallelogram linkage profiling mechanism 1, an electric adjustment mechanism 2, and a sensing control system.

[0024] As Figure 2 shown, the parallelogram linkage profiling mechanism 1 includes a front plate 100, an upper rod 110, and a lower rod 120.

[0025] Two upper rods 110 form a group, and two lower rods 120 form a group. The upper rods 110 and the lower rods 120 are both arranged between the front plate 100 and the single-body frame 3, and can rotate relative to the front plate 100 and the single-body frame 3. The front end and the rear end of the upper rod 110 are respectively rotatably connected to the top end of the front plate 100 and the upper part of the single-body frame 3; the front end and the rear end of the lower rod 120 are respectively rotatably connected to the bottom end of the front plate 100 and the lower part of the single-body frame 3.

[0026] As shown Figure 2 in the figure, the front ends of the two upper rods 110 are respectively rotatably connected to both sides of the top end of the front plate 100, and the front ends of the two lower rods 120 are respectively rotatably connected to both sides of the bottom end of the front plate 100.

[0027] Exemplarily, both sides of the front plate 100 have side edges, and pin holes are formed at the top end and the bottom end of the side edges, and a pin shaft is installed in the pin holes. The front end of the upper rod 110 is rotatably connected to the pin shaft at the top end of the side edge, and the pin shaft at this position forms a rotation point, denoted as point A. The front end of the lower rod 120 is rotatably connected to the pin shaft at the bottom end of the side edge, and the pin shaft at this position forms another rotation point, denoted as point B.

[0028] As shown Figure 2 in the figure, the rear ends of the two upper rods 110 are rotatably connected to the upper part of the single body frame 3, and the rear ends of the two lower rods 120 are rotatably connected to the lower part of the single body frame 3.

[0029] As shown Figure 2 and Figure 3 in the figure, the electromagnetic force adjusting mechanism includes a driven rod 200, a fixed rod 210, an intermediate shaft 220, an electric push-pull rod 230, an arc track 240, a first roller 250 and a second roller 260.

[0030] The electric push-pull rod 230 includes a housing 231 and a push-pull rod 232. The intermediate shaft 220 is fixed between the middle and rear sections of the two upper rods 110. The connection position between the intermediate shaft 220 and the upper rod 110 is denoted as point C, and the top of the housing 231 is rotatably connected to the intermediate shaft 220.

[0031] The two driven rods 200 are in a group. The rear ends of the two driven rods 200 are respectively rotatably connected to both sides of the middle part of the housing 231, and the front ends of the two driven rods 200 are respectively rotatably connected to the connection position between the upper rod 110 and the front plate 100, that is, the pin shaft at point A.

[0032] The front end of the fixed rod 210 is fixedly connected to the middle part of the top end of the front plate 100. The rear end of the fixed rod 210 is fixedly connected to the top end of the arc track 240. The bottom end of the arc track 240 is fixedly connected to the middle part of the bottom end of the front plate 100. The arc track 240 is arranged with the midpoint of the line connecting the two points A as the center of the circle.

[0033] Both the first roller 250 and the second roller 260 are directly or indirectly connected to the push-pull rod 232 and are respectively arranged on the upper and lower sides of the arc track 240, that is, the first roller 250 is arranged on the upper side of the arc track 240, and the second roller 260 is arranged on the lower side of the arc track 240.

[0034] The described sensing control system includes an angle sensor 4 and a controller 5. The controller 5 is respectively connected to the angle sensor 4 and the electric push-pull rod 230. The angle sensor 4 is used to collect the change information of the traction angle and transmit it to the controller 5, and the controller 5 controls the operation of the electric push-pull rod 230.

[0035] In a preferred embodiment, the sensing control system includes an optical sensor 6. The optical sensor 6 is connected to the controller 5, and this optical sensor 6 is used to collect the water content of the soil. Preferably, the optical sensor 6 is installed at the bottom of the front plate 100 of the parallelogram profiling mechanism.

[0036] In a relatively specific embodiment, a first sleeve 130 is fixed to the upper part of the single-frame 3. Between the rear ends of the two upper rods 110 is connected by a bolt, and this bolt passes through the first sleeve 130, and this bolt can rotate inside the first sleeve 130. A second sleeve 140 is fixed to the lower part of the single-frame 3. Between the rear ends of the two lower rods 120 is connected by a bolt, and this bolt passes through the second sleeve 140, and this bolt can rotate inside the second sleeve 140. In addition, a connecting pipe 150 is also fixed between the two lower rods 120.

[0037] Exemplarily, the single-frame 3 includes a lower frame body and an upper frame body longitudinally fixed at the front end of the lower frame body. The first sleeve 130 is fixed to the top of the upper frame body, and the second sleeve 140 is fixed to the front end of the lower frame body.

[0038] Based on the above embodiments, this embodiment provides an optional installation method for the angle sensor 4. As Figure 4 shown, the angle sensor 4 includes an angle sensor fixed disk 400 and an angle sensor moving disk 410. The angle sensor fixed disk 400 is installed at one end of the second sleeve 140, and the angle sensor moving disk 410 is installed at the rear end of the lower rod 120 corresponding to the angle sensor fixed disk 400. The angle sensor moving disk 410 can rotate together with the lower rod 120.

[0039] In another relatively specific embodiment, as Figure 3 、 Figure 5 shown, the first roller 250 is installed on the first roller shaft 280, the second roller 260 is installed on the second roller shaft 290, and the ends of the first roller shaft 280 and the second roller shaft 280 are connected by a connecting plate 270; the first roller shaft 280 is connected to the bottom of the push-pull rod 232.

[0040] Another typical embodiment of the present invention provides a seeding monomer, which includes the downforce automatic adjustment device described in the above embodiments, as well as a metering system 7, a double-disc furrow opener 8, a depth-limiting mechanism 9, a pressing device 10, and a seeding depth adjustment device 11.

[0041] Among them, asFigure 6 As shown in the figure, the metering system 7 includes a seed box 700, a metering device 710, and a metering tube 720. The metering device 710 is fixedly installed on the single-frame 3. The seed box 700 is fixed above the metering device 710. The bottom of the metering device 710 is connected to the metering tube 720, and the bottom of the metering tube 720 is located inside the double-disc furrow opener 8.

[0042] The double-disc furrow opener 8 is arranged below the single-frame 3 and is installed on the single-frame 3 through a disc shaft 810.

[0043] The depth-limiting mechanism 9 is arranged behind the double-disc furrow opener 8 and includes depth-limiting wheels 910, wheel arms 920, a wheel shaft 960, a limit block 930, a limit block shaft 940, and a downward pressure sensor 950.

[0044] The two depth-limiting wheels 910 are respectively located at the outer and rear positions of the double-disc furrow opener 8. The depth-limiting wheels 910 are connected to the single-frame 3 through the wheel arms 920. One end of the wheel arm 920 is connected to the depth-limiting wheel 910, and the other end of the wheel arm 920 is connected to the single-frame 3 through the wheel shaft 960. The wheel shaft 960 is fixed to the single-frame 3.

[0045] Reference Figure 7 As shown in the figure, the limit block shaft 940 is installed on the single-frame 3 above the wheel arm 920. The limit block 930 is provided with a middle hole, and the middle hole of the limit block 930 passes through the limit block shaft 940. The downward pressure sensor 950 is installed at the lower end of the limit block shaft 940 and is inside the middle hole of the limit block 930. The limit block shaft 940 is connected to the seeding depth adjustment device 11. The seeding depth adjustment device 11 is installed behind the single-frame 3. The seeding depth adjustment device 11 adjusts the seeding depth by adjusting the position of the limit block shaft 940.

[0046] The pressing device 10 is arranged behind the seeding unit and is connected to the single-frame 3 through a shaft.

[0047] When starting the operation, the tractor pulls the seeding unit forward through the suspension device. The optical sensor 6 collects the soil moisture content information and transmits it to the controller 5. The controller 5, according to the information collected by the optical sensor 6, sends the information on the range of the set value of the downward pressure of the seeding unit to the electric push rod 230 and the downward pressure sensor 950 in real time.

[0048] The parallelogram linkage profiling mechanism 1 pulls the single-frame 3 forward along with the undulation of the ground. The electric push rod 230 adjusts the force addition or subtraction in real time according to the angle change information of the angle sensor 4 and along with the up and down floating of the parallelogram linkage profiling mechanism 1 to make the downward pressure of the seeding unit within the set value range.

[0049] Under the combined action of the gravity of the seeding unit, the decomposed traction force of the tractor, and the pushing and pulling force of the electric push-pull rod 230, the double-disc furrow opener 8 enters the soil to form a seed furrow. Seeds are discharged from the seed box 700 into the seed furrow through the metering device 710 and the seed tube 720. The depth-limiting wheel 910 rotates upward under the action of the soil reaction force. The depth-limiting wheel 910 drives the wheel arm 920 to press against the limit block 930, and the limit block 930 also presses against the downward pressure sensor 950. The downward pressure sensor 950 real-time feeds back the actual value information of the downward pressure of the unit frame 3 to the controller 5. At the same time, the depth-limiting wheel 910 squeezes and covers the soil in the seed furrow, and the pressing device 10 completes the pressing work on the seed furrow.

[0050] The following describes the process of downward pressure adjustment for different states. The main formula involved is: F = G + (±F1sinα) + (±F2); Where, F is the downward pressure of the seeding unit, G is the weight of the seeding unit, F1 is the traction force of the tractor on the seeding unit, F2 is the pushing and pulling force of the electric push-pull rod, and α is the traction angle of the seeding unit, which refers to the angle between the traction line and the horizontal center line of the seeding unit during the traction process.

[0051] Set the initial state (when α is 0). At this time, the traction force of the tractor on the seeding unit only has a forward force and no decomposed force. The push-pull rod 232 pulls back the second roller 260, and correspondingly pulls back the upper rod 110, and applies a certain downward force to the seeding unit, so that the downward pressure of the seeding unit is maintained within the set value range.

[0052] When α changes from 0° to 30°, the unit frame 3 of the seeding unit floats upward relative to the front plate 100. The upper rod 110 and the lower rod 120 simultaneously rotate counterclockwise around points A and B at their respective front ends. At the same time, a relative rotation occurs between the moving disk 410 of the angle sensor at the rear end of the lower rod 120 and the fixed disk 400 of the angle sensor. The angle sensor 4 transmits the α change information to the controller 5. The controller 5 issues an adjustment command to the electric push-pull rod 230 in real time according to the angle change information. The upper rod 110 drives the housing 231 to rotate counterclockwise through the intermediate shaft 220, and the driven rod 200 also rotates counterclockwise with the housing 231. When the push-pull rod 232 rotates counterclockwise, it pulls back the second roller 260 according to the command of the controller 5. The second roller 260 rolls upward along the outer side of the arc track 240. Correspondingly, the electric push-pull rod 230 pulls back the upper rod 110. As α increases, the downward decomposed force of the traction force also gradually increases, and the adjustment of the electric push-pull rod 230 pulling back and applying a downward force gradually decreases. When F2 decreases to 0, the push-pull rod 232 extrapolates the first roller 250 according to the command of the controller 5, and correspondingly also extrapolates the upper rod 110. The electric push-pull rod 230 extrapolates and adjusts the upward force reduction, and the adjustment of the upward force reduction gradually increases.

[0053] When the follower rod 200, the housing 231, and the line segment connecting points A and C are projected onto the same plane, a triangle is formed. Since the arc-shaped track 240 is centered at the midpoint of the line connecting the two A points and fixed to the front plate 100, the formed triangle also rotates around the midpoint of the line connecting the two A points. Therefore, the first roller 250 and the second roller 260 can roll along the arc-shaped track 240 with the push-pull rod 232. Due to the constraint of the arc-shaped track 240 and the formed triangle on the push-pull rod 232, when the push-pull rod 232 rotates with the upper rod 110, whether it is pushed out or pulled back, the length of the push-pull rod 232 extending out of the housing 231 remains unchanged. This also enables the electric push-pull rod 230 to exert a force-increasing or force-decreasing adjustment on the upper rod 110 in real time when it rotates with the parallelogram profiling mechanism 1.

[0054] When α changes from 30° to 0°, the electric push-pull rod 230 rotates clockwise with the parallelogram profiling mechanism 1. As α becomes smaller, the downward decomposition force of the traction force also gradually becomes smaller. The push-pull rod 232 pushes out the first roller 250 and the upward force-decreasing adjustment gradually becomes smaller. When F2 decreases to 0, the push-pull rod 232 pulls back the second roller 260 according to the instruction of the controller 5, and correspondingly pulls back the upper rod 110. The electric push-pull rod 230 pulls back and makes a downward force-increasing adjustment, and the downward force-increasing adjustment gradually becomes larger.

[0055] When α changes from 0° to -30°, the electric push-pull rod 230 rotates clockwise with the parallelogram profiling mechanism 1. As α becomes larger, the upward decomposition force of the traction force also gradually becomes larger. The electric push-pull rod 230 pulls back the second roller 260 and the downward force-increasing adjustment gradually becomes larger.

[0056] When α changes from -30° to 0°, the electric push-pull rod 230 rotates counterclockwise with the parallelogram profiling mechanism 1. As α becomes smaller, the upward decomposition force of the traction force also gradually becomes smaller. The electric push-pull rod 230 pulls back the second roller 260 and the downward force-increasing adjustment gradually becomes smaller.

[0057] The downward pressure sensor 950 real-time feeds back the actual downward pressure value at the double-disc furrow opener 8 to the controller 5. When the actual downward pressure exceeds the set value range, the controller 5 issues an immediate auxiliary adjustment instruction to the electromagnetic force adjustment mechanism to quickly adjust it to within the set value range.

[0058] The scope of protection required by the present invention is not limited to the above specific embodiments. For those skilled in the art, the present invention can have various deformations and modifications. Any modifications, improvements, and equivalent replacements made within the concept and principle of the present invention should be included within the protection scope of the present invention.

Claims

1. An automatic downforce adjustment device, characterized in that, It includes a parallelogram copying mechanism (1), an electric adjustment mechanism (2) and a sensing control system; The described parallelogram copying mechanism (1) includes a front plate (100), upper rods (110) and lower rods (120). Two upper rods (110) form a group, and two lower rods (120) form a group; The front end and the rear end of the upper rod (110) are respectively rotatably connected to the top of the front plate (100) and the upper part of the monomer frame (3); the front end and the rear end of the lower rod (120) are respectively rotatably connected to the bottom of the front plate (100) and the lower part of the monomer frame (3); The described electric adjustment mechanism (2) includes a driven rod (200), a fixed rod (210), an intermediate shaft (220), an electric push-pull rod (230), an arc track (240), a first roller (250) and a second roller (260); The electric push-pull rod (230) includes a housing (231) and a push-pull rod (232). The intermediate shaft (220) is fixed between the middle and rear sections of the two upper rods (110), and the top of the housing (231) is rotatably connected to the intermediate shaft (220); Two driven rods (200) form a group. The rear ends of the two driven rods (200) are respectively rotatably connected to both sides of the middle of the housing (231), and the front ends of the two driven rods (200) are respectively rotatably connected to the connection part of the upper rod (110) and the front plate (100); The front end of the fixed rod (210) is fixedly connected to the middle of the top of the front plate (100), the rear end of the fixed rod (210) is fixedly connected to the top of the arc track (240), and the bottom end of the arc track (240) is fixedly connected to the middle of the bottom of the front plate (100); Both the first roller (250) and the second roller (260) are directly or indirectly connected to the push-pull rod (232) and are respectively arranged on the upper and lower sides of the arc track (240); The described sensing control system includes an angle sensor (4) and a controller (5). The controller (5) is respectively connected to the angle sensor (4) and the electric push-pull rod (230).

2. The downforce automatic adjustment device according to claim 1, characterized in that: The sensing control system includes an optical sensor (6). The optical sensor (6) is connected to the controller (5) and is used to collect the water content of the soil.

3. The downforce automatic adjustment device according to claim 1 or 2, characterized in that: A first sleeve (130) is fixed to the upper part of the monomer frame (3). The rear ends of the two upper rods (110) are connected by bolts and the bolts pass through the first sleeve (130); a second sleeve (140) is fixed to the lower part of the monomer frame (3). The rear ends of the two lower rods (120) are connected by bolts and the bolts pass through the second sleeve (140).

4. The automatic downforce adjustment device according to claim 3, characterized in that: The described angle sensor (4) includes an angle sensor fixed disk (400) and an angle sensor moving disk (410). The angle sensor fixed disk (400) is installed at one end of the second sleeve (140), and the angle sensor moving disk (410) is installed at the rear end of the lower rod (120) corresponding to the angle sensor fixed disk (400).

5. The automatic downforce adjustment device according to claim 4, characterized in that: The first roller (250) is installed on the first roller shaft (280), the second roller (260) is installed on the second roller shaft (290), and the ends of the first roller shaft (280) and the second roller shaft (290) are connected by a connecting plate (270); the first roller shaft (280) is connected to the bottom of the push-pull rod (232).

6. A seeding unit, characterized in that: It includes a metering system (7), a double-disc furrow opener (8), a depth-limiting mechanism (9), a pressing device (10), a seeding depth adjustment device (11), and the downforce automatic adjustment device according to any one of claims 1-5.

7. The seeding monomer according to claim 6, wherein: The metering system (7) includes a seed box (700), a metering device (710), and a metering pipe (720). The metering device (710) is fixedly installed on the single-frame (3). The seed box (700) is fixed above the metering device (710). The bottom of the metering device (710) is connected to the metering pipe (720). The bottom of the metering pipe (720) is located inside the double-disc furrow opener (8).

8. The seeding monomer according to claim 6 or 7, characterized in that: The double-disc furrow opener (8) is arranged below the single-frame (3) and is installed on the single-frame (3) through a disc shaft (810).

9. The seeding monomer according to claim 8, characterized in that: The depth-limiting mechanism (9) is arranged behind the double-disc furrow opener (8) and includes depth-limiting wheels (910), wheel arms (920), a wheel shaft (960), a limit block (930), a limit block shaft (940), and a downforce sensor (950). The two depth-limiting wheels (910) are respectively located at the outer rear of the double-disc furrow opener (8). The depth-limiting wheels (910) are connected to the single-frame (3) through the wheel arms (920). One end of the wheel arm (920) is connected to the depth-limiting wheel (910), and the other end of the wheel arm (920) is connected to the single-frame (3) through the wheel shaft (960). The limit block shaft (940) is installed on the single-frame (3) above the wheel arm (920). The limit block (930) is provided with a middle hole, and the middle hole of the limit block (930) passes through the limit block shaft (940). The downforce sensor (950) is installed at the lower end of the limit block shaft (940) and inside the middle hole of the limit block (930). The limit block shaft (940) is connected to the seeding depth adjustment device (11). The seeding depth adjustment device (11) is installed behind the single-frame (3) and adjusts the seeding depth by adjusting the position of the limit block shaft (940).

10. The seeding monomer according to claim 9, characterized in that: The pressing device (10) is arranged behind the seeding unit and is connected to the single-frame (3) through a shaft.

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