Seed metering drum structure and seed metering device for oilseed rape

Abstract

The application provides a seed feeding roller structure and a seed feeder for rape, and the seed feeding roller structure comprises a seed feeding roller, a plurality of seed filling holes are arranged on the seed feeding roller, the seed filling holes sequentially comprise a Bezier type hole, an air hole and a tapered hole from outside to inside, the outer opening of the Bezier type hole is a rectangular orifice, the cross section of the Bezier type hole along the radial direction of the seed feeding roller is a third-order Bezier curve, the bottom of the Bezier type hole is provided with an air port connected with one end of the air hole, the other end of the air hole is connected with a small end of the tapered hole, and a large end of the tapered hole is arranged on the inner wall of the seed feeding roller. The Bezier type hole can be adapted to rape seeds with different shapes and sizes, the rape seeds can pass through the Bezier type hole smoothly, the Bezier type hole is not easy to be blocked or cause air flow energy loss, the seed breaking rate in the seeding process is greatly reduced, the Bezier curve can also reduce the impact of air flow on the hole wall, reduce the generation of air flow vortex, and ensure the uniformity and stability of seed feeding.

Description

Technical Field

[0001] This invention belongs to the field of agricultural machinery technology, specifically relating to a seed metering roller structure and seed metering device for rapeseed. Background Technology

[0002] Rapeseed, as an important oilseed crop, is of great significance to agricultural and economic development. Sowing, as a key step in mechanized planting, directly affects the sowing quality due to the performance of the seed metering device. Existing seed metering devices generally use grooved wheel holes, straight round holes, or conical holes. During the operation of the seed metering device, if it encounters seeds that are too large or too small, these holes are prone to unstable seed filling, resulting in low seed filling efficiency. They are also prone to problems such as seed jamming and seed knocking. Summary of the Invention

[0003] To solve the above-mentioned technical problems, the present invention provides a seed metering roller structure and a seed metering device for rapeseed.

[0004] The technical solution adopted by the present invention to solve its technical problem is: a seed metering roller structure for rapeseed, including a seed metering roller, wherein the seed metering roller is provided with a plurality of rings of seed filling holes, wherein the seed filling holes include, from the outside to the inside, a Bezier-type hole, an air hole and a conical hole, wherein the outer opening of the Bezier-type hole is a rectangular opening, its cross section along the radial direction of the seed metering roller is a third-order Bezier curve, and its bottom is provided with an air port connected to one end of the air hole, the other end of the air hole is connected to the small end of the conical hole, and the large end of the conical hole is located on the inner wall of the seed metering roller.

[0005] Optionally, the parameters of the Bessel-type aperture are designed according to the force on the rapeseed seeds inside when it is in the horizontal direction, at which point the rapeseed seeds are at the critical point of being ejected. The seed metering roller is fitted with an arc-shaped plate, and the elastic force F of the arc-shaped plate on the rapeseed seeds... N2 The frictional force F between the rapeseed and the curved plate is 0. f2 The resultant force on the rapeseed is 0, providing the centripetal force. The parameters of the Bezier-type aperture include the length L of the rectangular aperture, the width W of the rectangular aperture, the height H of the Bezier-type aperture, the diameter D of the air inlet, and the inclination angle θ of the straight section of the aperture, where the length L = l max +k L Width W = w max +k w Height H = k H h max The diameter of the air inlet, D, is ≤0.9b. min The inclination angle θ of the straight section of the hole is calculated by the following formula.

[0006]

[0007] In the formula, l maxk represents the maximum length of a rapeseed seed. L k is the length adjustment coefficient. L Take 1-1.5mm, w max k represents the maximum width of the rapeseed seed. w k is the width adjustment coefficient. w Take 1-1.2 mm, h max k represents the maximum height of the rapeseed seed. H k is the height adjustment coefficient. H Take 0.9–1.1 mm, b min Let G be the minimum size of the rapeseed seed, G be the weight of the rapeseed seed, m be the mass of the rapeseed seed, and g be the acceleration due to gravity. The supporting force of the lower wall of the perforation on the rapeseed. ω is the frictional force between the rapeseed seed and the lower wall of the die, r is the radius of the seed metering roller, ω is the angular velocity of the seed metering roller, and μ is the coefficient of friction between the seed metering roller and the rapeseed seed, with μ set to 0.3.

[0008] Optionally, the maximum length l of the rapeseed seed max Take 2.03mm as the maximum height w of the rapeseed seed. max Take 2.03 mm as the maximum height h of the rapeseed seed. max Take 2.03mm, the smallest size b of rapeseed. min Take 1.8mm.

[0009] Optionally, the radius r of the seed metering roller is 74 mm, the angular velocity ω of the seed metering roller is 0.5π≤ω≤π, and the friction coefficient μ between the seed metering roller and the rapeseed is 0.3, resulting in an inclination angle θ∈[12.44°, 15.63°] for the straight section of the orifice.

[0010] Optionally, the rectangular opening of the Bezier-type hole has a length L of 3.3 mm, a width W of 3.2 mm, and a height H of 2.2 mm.

[0011] Optionally, the equation of the third-order Bézier curve is determined by the following formula:

[0012] B(t)=(1-t) 3 P0+3(1-t) 2 tP1+3(1-t)t 2 P2+t 3 P3,

[0013] In the formula, t is a parameter with a value range of [0,1]. P0, P1, P2, and P3 are the starting point, two control points, and the ending point, respectively. P0 = (0,0), P1 = (-0.5,3), P2 = (3,1.9), and P3 = (2.8,0).

[0014] Optionally, the Bezier-type hole has a chamfer at the rectangular opening.

[0015] Accordingly, the present invention also provides a seed metering device for rapeseed, comprising a roller cover, a seed feeding pipe, and the aforementioned seed metering roller structure for rapeseed; wherein, the roller cover is a cavity structure with an open top, comprising side plates of the cover arranged parallel to both ends, a pair of inclined plates symmetrically arranged between the two side plates and inclined inward, and an arc-shaped plate arranged between the bottoms of the two inclined plates and protruding outward, wherein the side of the arc-shaped plate has an opening near the bottom, the width of which in the circumferential direction can completely cover at least one seed filling hole; the seed metering roller structure comprises a seed metering roller and a high-pressure chamber, the seed metering roller being rotatably mounted on a rotating shaft. Inside the roller cover, the lower part of the seed metering roller is located in the groove of the arc-shaped plate, and its upper part extends out of the groove of the arc-shaped plate. The arc-shaped plate, the inclined plate and the seed metering roller are fitted with a clearance. The cavity between the outer wall of the upper part of the seed metering roller and the two inclined plates and the two side plates of the cover forms a seed filling area. The high-pressure chamber is closely attached to the inner wall of the seed metering roller at the position corresponding to the opening of the arc-shaped plate. The high-pressure chamber is filled with airflow that can blow the rapeseed seeds located in the Bessel-type hole at the high-pressure chamber outward. The seed feeding pipe is located at the bottom of the arc-shaped plate. The upper opening of the seed feeding pipe is connected to the opening of the arc-shaped plate, and its lower opening is connected to the outside.

[0016] Optionally, end caps are fitted at both ends of the rotating shaft in the gap outside the seeding roller, and the end caps are fixedly installed on the corresponding side plates of the cover. The high-pressure chamber is fixedly installed on the end caps.

[0017] Optionally, the opening of the arc-shaped plate can completely cover 2-5 seed filling holes in the circumferential direction.

[0018] The beneficial effects of this invention are as follows: The seed metering roller structure for rapeseed provided by this invention adopts the form of a seed metering roller, and several rings of seed filling holes are opened on the seed metering roller. The seed filling holes include, from the outside to the inside, a Bezier-shaped hole, an air hole, and a conical hole. The Bezier-shaped hole can effectively adapt to rapeseed seeds of different shapes and sizes. Its cross-section is a third-order Bezier curve. This special curve can ensure that the shape of the hole is smooth while having an appropriate curvature so that the rapeseed seeds can pass through smoothly without getting stuck or causing airflow energy loss, which greatly reduces the breakage rate of seeds during the sowing process. Moreover, when the airflow blows from the conical hole into the Bezier-shaped hole through the air hole, the Bezier curve contour design can also reduce the impact of the airflow on the hole wall, thereby reducing the generation of airflow eddies and ensuring the uniformity and stability of seed metering.

[0019] On the other hand, this invention also provides a seed metering device for rapeseed. Through the structural design of the roller cover, the seeds in the filling area are encased in the orifice as the seed metering roller rotates. The seeds in the orifice are cleaned by the action of the inclined plate and protected by the arc plate. Finally, the seeds rotate together with the seed metering roller to the bottom of the seed metering roller. Under the action of the seed's own weight and the positive pressure airflow in the high-pressure chamber, the seeds are blown down by the seed delivery pipe to complete the seed metering. This invention adopts an internal blowing type + mechanical roller type. By controlling the curvature of the orifice, the airflow is accelerated when passing through, which can push the seeds more effectively, optimize the seed transmission and discharge path, and avoid the blockage of the orifice. The Bezier orifice is used for rapeseed sowing, which can realize the sowing of rapeseed of different shapes, sizes and shapes. The seed metering device adopts a seed metering roller for centralized seed metering, which significantly reduces the seed breakage rate, improves the seed filling performance, and prevents seed jamming. It has high sowing efficiency and reliability, and the structure is simpler and more integrated. Through the design of the roller cover, it can ensure that the seeds are smoothly transported to the seed delivery pipe during the rotation of the seed metering roller. Attached Figure Description

[0020] The present invention will be further described below with reference to the accompanying drawings and embodiments. In the accompanying drawings:

[0021] Figure 1 This is a schematic diagram of the seed metering roller structure for rapeseed provided by the present invention;

[0022] Figure 2 This is a top view of the Bezier-type hole in an embodiment of the present invention;

[0023] Figure 3 This is a radial cross-sectional view of the Bezier-type hole in an embodiment of the present invention;

[0024] Figure 4 This is a third-order Bezier curve diagram of the Bezier-type hole in an embodiment of the present invention;

[0025] Figure 5 This is a force analysis diagram of rapeseed seeds inside Bessel-type holes in an embodiment of the present invention;

[0026] Figure 6 This is a schematic diagram of the structure of the seed metering device for rapeseed provided by the present invention.

[0027] In the diagram: 100 - Seed metering roller structure, 101 - Seed metering roller, 102 - Seed filling hole, 102.1 - Bezier type hole, 102.2 - Air hole, 102.3 - Conical hole, 103 - High pressure chamber, 104 - Rotating shaft, 200 - Roller cover, 201 - Cover side plate, 202 - Inclined plate, 203 - Arc plate, 204 - Seed filling area; 300 - Seed feeding pipe, 301 - Fixing plate. Detailed Implementation

[0028] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of the embodiments of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0029] In the description of this invention, it should be noted that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention. In addition, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0030] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances. Furthermore, in the description of this invention, unless otherwise stated, "a plurality of" or "several" means two or more.

[0031] like Figures 1-5 As shown, the present invention provides a seed metering roller structure for rapeseed, including a seed metering roller 101. The seed metering roller 101 is provided with a plurality of rings of seed filling holes 102. The seed filling holes 102 include, from the outside to the inside, a Bezier-shaped hole 102.1, an air hole 102.2 and a conical hole 102.3. The outer opening of the Bezier-shaped hole is a rectangular orifice, and its cross section along the radial direction of the seed metering roller is a third-order Bezier curve. The bottom of the orifice is provided with an air port connected to one end of the air hole. The other end of the air hole is connected to the small end of the conical hole. The large end of the conical hole is located on the inner wall of the seed metering roller. More preferably, the air hole is inclined, which can reduce the turbulence formed by the gas in the orifice.

[0032] Experiments have shown that the opening size and width of the Bezier-type aperture are crucial dimensions affecting seed filling and spacing effects, thus requiring further analysis. Therefore, this invention optimizes the aperture parameters to ensure that only one seed is filled into a single aperture. In one embodiment, such as... Figure 5As shown, the parameters of the Bessel-type aperture are designed based on the force exerted on the rapeseed seeds when it is in the horizontal direction. At this point, the rapeseed seeds are at the critical point of being ejected. The seed metering roller is fitted with an arc-shaped plate, and the elastic force F exerted by the arc-shaped plate on the rapeseed seeds... N2 The frictional force F between the rapeseed and the curved plate is 0. f2 The resultant force on the rapeseed seed is 0, providing the centripetal force. The inclination angle θ of the bezel orifice is calculated based on the force acting on the seed. The parameters of the bezel orifice include the length L of the rectangular opening, the width W of the rectangular opening, the height H of the bezel orifice, the diameter D of the air inlet, and the inclination angle θ of the straight section of the orifice. The inclination angle is the angle between the frictional force exerted by the bezel orifice wall on the seed and the horizontal direction. To prevent clogging and facilitate seed filling, the length L = l max +k L Width W = w max +k w Height H = k H h max This avoids the possibility of two rapeseed seeds being trapped inside the cavity; the diameter of the air vent, D, is ≤0.9b. min To prevent rapeseed seeds from falling into the air chamber, the inclination angle θ of the straight section of the pore is calculated using the following formula.

[0033]

[0034] In the formula, l max k represents the maximum length of a rapeseed seed. L k is the length adjustment coefficient. L Take 1-1.5mm, w max k represents the maximum width of the rapeseed seed. w k is the width adjustment coefficient. w Take 1-1.2 mm, h max k represents the maximum height of the rapeseed seed. H k is the height adjustment coefficient. H Take 0.9–1.1 mm, b min Let G be the minimum size of the rapeseed seed, G be the weight of the rapeseed seed, and m be the mass of the rapeseed seed, where m is taken as 4.45 × 10⁻⁶. -6 kg, where g is the acceleration due to gravity. The supporting force of the lower wall of the perforation on the rapeseed. Let r be the frictional force between the rapeseed seed and the lower wall of the bezier hole, ω be the radius of the seed metering roller, ω be the angular velocity of the seed metering roller, and μ be the coefficient of friction between the seed metering roller and the rapeseed seed, with μ set to 0.3. This invention, through precise design of the shape and size of the Bezier hole, ensures that the seed meterer can be used with rapeseed seeds of different shapes and sizes, and maximizes the filling efficiency by ensuring that only one seed is filled into each hole, preventing seed jamming, knocking, double-seeding, and missed sowing. It also ensures smooth seed filling during the process, guaranteeing uniformity and stability of seed metering and significantly reducing seed breakage during sowing.

[0035] Since the triaxial dimensions and shape of the seed are key parameters for designing the seed metering orifice, the external dimensions of the rapeseed seed must be determined first when designing the parameters of the Bezier orifice. Therefore, in one embodiment, the maximum length l of the rapeseed seed is... max Take 2.03mm as the maximum height w of the rapeseed seed. max Take 2.03 mm as the maximum height h of the rapeseed seed. max Take 2.03mm, the smallest size b of rapeseed. min Using 1.8mm as an example, the Bessel-type aperture parameters designed based on the above seed size are: length L = 3.03~3.53mm, width W = 2.03~3.23mm, height H = 1.83~2.23mm, and air vent diameter D ≤ 1.62mm. This aperture design can be applied to rapeseed seeds of different shapes and sizes. Even better, the air vent diameter is 1.4mm.

[0036] At the same sowing speed, if the diameter of the seed metering roller is too small, the rotation speed of the seed meterer will be relatively high, and the time for the seed hole to pass through the seed cluster will be too short, which is not conducive to seed filling; if the diameter of the seed metering roller is too large, the processing quality and cost requirements of the seed meterer will be too high, and the size space will be too large. Therefore, the diameter of the seed metering roller is generally 80-200mm. Preferably, in one embodiment, the present invention determines the diameter of the seed metering roller to be 148mm according to actual needs, that is, the radius r is 74mm. According to the rapeseed sowing speed, the rotation speed of the seed metering roller is generally set to 15-30 rpm, that is, the angular velocity ω of the seed metering roller is 0.5π≤ω≤π, and the friction coefficient μ between the seed metering roller and the rapeseed is 0.3, so that the inclination angle θ∈[12.44°, 15.63°] of the straight section of the seed hole is obtained.

[0037] Based on stress analysis and simulation experiments, the optimal seed-rearing effect is achieved by combining a Bezier curve and a straight line segment (the aforementioned "volute-shaped" orifice). The length of the straight line segment on the left side of the orifice is 0.3 mm, and the length l of the straight line segment on the right side (the side of the vent hole) is 0.5 mm. Therefore, the groove depth of the Bezier curve segment of the orifice is determined to be 1.9 mm, the opening length to be 2.8 mm, and the designed orifice width to be 2.8 mm. To prevent seed damage upon entering the orifice, a chamfer is designed at the orifice opening. Through a series of simulation experiments, it is found that a 0.1 mm straight line segment h on the left side of the orifice is used to extend and round the corner at the end of the Bezier line segment. Therefore, in one embodiment, such as... Figure 3 As shown, the total height H of the hole is 2.2mm, the total length L of the hole after rounding is 3.3mm, and the total width W after rounding is 3.2mm, which meets the requirements.

[0038] Based on the requirements for rapeseed seed spacing and combined with gas-solid coupling, a third-order Bézier curve and a straight line segment are used to fit the aperture profile. The Bézier curve ensures that the aperture shape maintains a smooth flow while having appropriate curvature, so that seeds can pass through smoothly without getting stuck or causing airflow energy loss. Therefore, in one embodiment, such as... Figure 4 As shown, the equation of the third-order Bézier curve is determined by fitting as follows:

[0039] B(t)=(1-t) 3 P0+3(1-t) 2 tP1+3(1-t)t 2 P2+t 3 P3,

[0040] In the formula, t is a parameter with a value range of [0,1]. P0, P1, P2, and P3 are the starting point, two control points, and the ending point, respectively. P0 = (0,0), P1 = (-0.5,3), P2 = (3,1.9), and P3 = (2.8,0).

[0041] Substituting these points into Bessel's equation, we get:

[0042] x(t) = -1.5t + 12t 2 -7.7t 3

[0043] y(t) = 9t - 12.3t 2 +3.3t 3

[0044] In one embodiment, such as Figure 2 , Figure 3 As shown, the Bessel-type aperture has a chamfer at the rectangular opening to prevent damage when seeds enter the aperture.

[0045] To address the problems of high airflow demand, high energy consumption, and high airtightness requirements in traditional air-blowing seed metering devices, as well as the issue of seed drop and leakage due to decreased seed filling performance in the orifice, this invention employs an internal blowing + mechanical roller seed metering device. Specifically, in one embodiment, as follows... Figure 6 As shown, a high-pressure chamber 103 is installed close to the inner wall of the seed metering roller 101, located on the seed-forming hole. The high-pressure chamber 103 contains an airflow that blows the seeds from the seed-forming hole located within it outwards. The arc length of the high-pressure chamber is less than half the circumference of the seed metering roller. Part of the seed metering roller is used for seed filling, and another part for seed metering. The high-pressure chamber corresponds to the seed metering area, and it is preferable for the high-pressure chamber to cover 2-5 rows of seed-forming holes, specifically 4. The seed metering roller has multiple sets of seed-forming holes, each set including 2-6 rings of holes. A high-pressure chamber is installed at each set of seed-forming holes. Using multiple sets of seed-forming holes can improve sowing efficiency.

[0046] This invention utilizes a high-pressure chamber installed on the inner wall of the seed metering drum. The high-pressure chamber is tightly fitted to the inner surface of the drum. A fan delivers gas into the high-pressure chamber through a duct, creating a positive pressure airflow. Seeds are directed into the high-pressure chamber area and expelled through the seed holes by the gas, completing the sowing process. The high-pressure chamber design solves the problem of seeds getting stuck at high speeds due to their own weight, and also addresses the issue of rapeseed, with its high oil content, easily adhering to the seed holes and causing uneven seed dispensing. This prevents seed hole blockage and ensures better consistency in seed metering across rows, achieving both precision and multi-row sowing.

[0047] This invention uses an internal air blowing + mechanical roller seed metering drum, which utilizes the working principle of gravity seed filling and airflow seed cleaning, and has better seed adaptability, lower airtightness requirements and higher sowing efficiency. In particular, the seed damage is less due to airflow cleaning.

[0048] Considering the existing rapeseed seed metering devices have problems such as complex structure, heavy weight, cumbersome installation and removal of the seed metering disc, inconvenient adjustment of seed feed rate, fixed air blowing height, and difficulty in assembling with other machinery, correspondingly, such as Figure 6 As shown, the present invention also provides a seed metering device for rapeseed, including a roller cover 200, a seed delivery pipe 300 and the above-mentioned seed metering roller structure 100 for rapeseed;

[0049] Among them, the roller cover 200 is a cavity structure with an open top, which includes a cover side plate 201 arranged parallel to both ends, a pair of inclined plates 202 symmetrically arranged between the two cover side plates and inclined inward, and an arc plate 203 arranged between the bottom of the two inclined plates and protruding outward. The side of the arc plate 203 is provided with an opening near the bottom, and the width of the opening in the circumferential direction can completely cover at least one seed filling hole.

[0050] The seed metering roller structure 100 includes a seed metering roller 101 and a high-pressure chamber 103. The seed metering roller 101 is rotatably installed inside the roller cover 200 via a rotating shaft 104. The lower part of the seed metering roller 101 is located in the groove of the arc plate 203, and its upper part extends out of the groove of the arc plate. The arc plate, the inclined plate and the seed metering roller are fitted with a clearance. The cavity between the outer wall of the upper part of the seed metering roller and the two inclined plates and the two cover side plates forms a seed filling area 204. The high-pressure chamber 103 is closely attached to the inner wall of the seed metering roller at a position corresponding to the opening of the arc plate. The high-pressure chamber is filled with an airflow that can blow the rapeseed seeds located in the Bessel-type holes at the high-pressure chamber outward.

[0051] The seeding pipe 300 is located at the bottom of the arc-shaped plate. The upper opening of the seeding pipe is connected to the opening of the arc-shaped plate, and its lower opening is connected to the outside.

[0052] In one embodiment, such as Figure 6 As shown, the two ends of the rotating shaft 104 are fitted with end caps (not shown in the figure) in the gap outside the seeding roller. The end caps are fixedly installed on the corresponding side plates of the cover, and the high-pressure chamber is fixedly installed on the end caps.

[0053] In one embodiment, such as Figure 6 As shown, the circumferential width of the opening of the arc-shaped plate 203 can completely cover 2-5 seed filling holes, which can improve seed dispensing efficiency. Specifically, in this embodiment, the opening of the arc-shaped plate 203 can cover 4 seed filling holes.

[0054] In one embodiment, such as Figure 6 As shown, the rotating shaft is a hexagonal shaft. The rotatable seed metering roller is fitted with fixed end caps on both sides with a clearance. A fixed arc-shaped plate is provided on the lower circumference of the seed metering roller. The hexagonal shaft, coaxial with the seed metering roller, passes through the seed metering roller and extends beyond the outer side of the end caps. A gear fixed on the hexagonal shaft is connected to a gear of the motor fixed on the side plate of the cover by a chain, and the motor drives the seed metering roller to rotate. The motor is also connected to a reducer, which can adjust the speed of the seed metering roller to achieve sowing at different speeds. The seed metering roller contains a motor and a reducer, and uses chain drive to connect the motor and the seed metering roller. This solves the problem of motor malfunction due to jamming during sowing. At the same time, the structural layout of the motor and reducer makes the entire seed metering roller more reasonable and compact, facilitating tractor installation and debugging.

[0055] This invention uses a motor reducer to adjust the speed of the seed metering drum, enabling the seed meterer to sow at different speeds. The seed meterer is equipped with a motor and a reducer, and uses chain drive to connect the motor and the seed metering drum, solving the problem of the motor failing to operate due to jamming during sowing. At the same time, the structural layout of the motor and reducer makes the whole machine more reasonable and compact, facilitating the installation and debugging of the tractor.

[0056] In one embodiment, such as Figure 6As shown, the seeding pipe 300 is fixedly connected to a fixed plate 301, and the two ends of the fixed plate 301 are fixedly connected to the side plates 201 of the cover on both sides.

[0057] The seed metering device for rapeseed provided by this invention adopts an air-blowing central seed metering principle. It features a compact and small structure. The seed metering roller uses an internal blowing + mechanical roller design, which optimizes the seed transport and discharge path, achieving precision and simultaneous seeding while avoiding clogging of the seed holes. The entire seed metering device utilizes a seed metering roller and seed box for centralized seed metering, significantly reducing seed breakage rate, improving seed filling performance, and preventing seed jamming. It boasts high sowing efficiency and reliability, a simple structure, and a high degree of integration. The seed box is composed of a front panel, a rear panel, two left side panels, a connecting plate, two telescopic support rods, and a seed metering device cover.

[0058] The seed metering device for rapeseed provided by this invention has the following specific installation steps: First, install the roller cover and position the side plates of the two cover shells. The two side plates of the cover shell can be fixed together by a crossbeam. Then, install the arc-shaped plate and a pair of inclined plates between the two side plates of the cover shell. The front end of the arc-shaped plate contacts the front inclined plate, and the rear end of the arc-shaped plate contacts the rear inclined plate. The two inclined plates are fitted with the outer surface of the seed metering roller with a clearance fit. This can avoid the working resistance between the seed metering roller and the inclined plates when rotating, and can also remove excess seeds from the upper surface of the orifice. The arc-shaped plate has an opening at the connection with each seeding pipe, which is the seed discharge groove. Seeding pipes are installed at both openings and are fixedly installed on the side plates of the cover shell on both sides by fixing plates. Then, install the rotating shaft with the seed metering roller. The two ends of the seed metering roller are fitted with a clearance fit. It has end caps, which are fixedly installed on the corresponding side plates of the cover. The seed metering roller has shaped holes for picking up seeds. Specifically, the seed metering roller has 6 rings of Bezier shaped holes symmetrically arranged on the left and right, with 3 rings as a group. Each group corresponds to a high-pressure chamber and a seed feeding pipe. Each ring has 90 shaped holes evenly distributed on the circumference. Then, the motor, reducer, and chain are installed. The motor and reducer are fixed to the side plates of the cover with screws. Next, the seed box for holding seeds is installed. The seed box is connected to the seed filling area above the roller cover. Finally, the high-pressure chamber is connected to the air source through an air pipe. There are two high-pressure chambers, which are respectively installed on the inner surface of the end caps on both sides with screws. Each high-pressure chamber has an air pipe interface, which is connected to an air pipe. The fan is connected to the air pipe through a tee. The high-pressure chamber and the shaped holes in the area of ​​the high-pressure chamber at the bottom form a positive pressure channel.

[0059] The entire working process of this invention when sowing rapeseed is as follows: Rapeseed seeds are poured into the seed box, the blower is turned on, and gas at a certain pressure is connected to the air pipe. The air pipe guides the gas into the high-pressure chamber, forming a positive pressure airflow in the high-pressure chamber area. After the blower starts, the drive motor is turned on. The motor drives the hexagonal shaft nested in the seed metering roller to rotate through gear transmission. The seed metering roller rotates accordingly. At this time, the seeds in the seed box are filled into the Bezier-shaped holes of the seed metering roller as the seed metering roller rotates. The rapeseed seeds filled into the Bezier-shaped holes are carried to the high-pressure chamber area below as the seed metering roller rotates. Under the airflow, the seeds that move to the bottom of the seed metering roller and are in the Bezier-shaped hole are blown out of the hole and fall into the seed delivery pipe through the opening of the arc plate for effective seed unloading, thus completing the sowing. At the same time, the motor drives the seed metering roller to rotate around the hexagonal axis. The rotation moves to the Bezier-shaped hole above the seed metering roller to fill the seed box with seeds. The seeds filled in the Bezier-shaped hole are cleaned by the action of the inclined plate and protected by the arc plate. Finally, the seeds move to the bottom of the seed metering roller and are metered by their own weight and positive pressure airflow.

[0060] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention, and should all fall within the protection scope of the appended claims of the present invention.

Claims

1. A seed metering roller structure for rapeseed, characterized in that, The device includes a seed metering roller, which has several rings of seed filling holes. The seed filling holes, from the outside to the inside, include a Bezier-type hole, an air hole, and a conical hole. The outer opening of the Bezier-type hole is a rectangular orifice, and its cross-section along the radial direction of the seed metering roller is a third-order Bezier curve. Its bottom is provided with an air port connected to one end of the air hole. The other end of the air hole is connected to the small end of the conical hole. The large end of the conical hole is located on the inner wall of the seed metering roller. The parameters of the Bessel-type aperture are designed based on the force exerted on the rapeseed seeds when it is in the horizontal direction, at which point the rapeseed seeds are at the critical point of being ejected. The seed dispensing roller is fitted with an arc-shaped plate, and the elastic force F exerted by the arc-shaped plate on the rapeseed seeds... N2 The frictional force F between the rapeseed and the curved plate is 0. f2 The resultant force on the rapeseed provides the centripetal force, which is 0. The parameters of the Bezier-type aperture include the length L of the rectangular aperture, the width W of the rectangular aperture, the height H of the Bezier-type aperture, the diameter D of the air inlet, and the inclination angle θ of the straight section of the aperture, where the length L = l max +k L Width W = W max +k w Height H=k H h max The diameter of the air inlet, D, is ≤0.9b. min The inclination angle of the straight section of the hole is calculated using the following formula. ， In the formula, l max k represents the maximum length of a rapeseed seed. L k is the length adjustment coefficient. L Take 1~1.5mm, W max k represents the maximum width of the rapeseed seed. w k is the width adjustment coefficient. w Take 1~1.2mm, h max k represents the maximum height of the rapeseed seed. H k is the height adjustment coefficient. H Take 0.9~1.1mm, b min Let G be the minimum size of the rapeseed seed, m be the weight of the rapeseed seed, g be the acceleration due to gravity, and F be the minimum velocity of the rapeseed seed. N1 For the supporting force of the pore wall on the rapeseed, F f1 ω is the frictional force between the rapeseed and the wall of the seed metering cylinder, r is the radius of the seed metering cylinder, ω is the angular velocity of the seed metering cylinder, and μ is the coefficient of friction between the seed metering cylinder and the rapeseed, which is taken as 0.

3. The equation of the third-order Bézier curve is determined by the following formula: ， In the formula, t is a parameter with a value range of [0,1]. P0, P1, P2, and P3 are the starting point, two control points, and the ending point, respectively. P0 = (0,0), P1 = (-0.5,3), P2 = (3,1.9), and P3 = (2.8,0).

2. The seed metering roller structure for rapeseed according to claim 1, characterized in that, The maximum length of the rapeseed seed l max Take 2.03 mm as the maximum width W of the rapeseed seed. max Take 2.03 mm as the maximum height h of the rapeseed seed. max Take 2.03mm, the smallest size b of rapeseed. min Take 1.8mm.

3. The seed metering roller structure for rapeseed according to claim 2, characterized in that, The radius of the seed metering roller is taken as 74 mm, and the angular velocity of the seed metering roller is taken as 0.5π≤ω≤π, resulting in the inclination angle θ∈[12.44°, 15.63°] of the straight section of the orifice.

4. The seed metering roller structure for rapeseed according to claim 3, characterized in that, The rectangular opening of the Bezier-type hole has a length L of 3.3 mm, a width W of 3.2 mm, and a height H of 2.2 mm.

5. The seed-metering roller structure for rapeseed according to claim 1, characterized in that, The Bessel-type hole has a chamfer at the rectangular opening.

6. A seed metering device for rapeseed, characterized in that, Includes a roller cover, a seeding pipe, and a seed-discharging roller structure for rapeseed as described in any one of claims 1-5; wherein, The roller cover is a cavity structure with an open top. It includes side plates of the cover arranged parallel to both ends, a pair of inclined plates symmetrically arranged between the two side plates and inclined inward, and an arc plate arranged between the bottom of the two inclined plates and protruding outward. The side of the arc plate has an opening near the bottom, and the width of the opening in the circumferential direction can completely cover at least one seed filling hole. The seed metering roller structure includes a seed metering roller and a high-pressure chamber. The seed metering roller is rotatably installed inside the roller cover via a rotating shaft. The lower part of the seed metering roller is located in the groove of the arc-shaped plate, and its upper part extends out of the groove of the arc-shaped plate. The arc-shaped plate, the inclined plate and the seed metering roller are fitted with a clearance. The cavity between the outer wall of the upper part of the seed metering roller and the two inclined plates and the two side plates of the cover forms a seed filling area. The high-pressure chamber is closely attached to the inner wall of the seed metering roller at a position corresponding to the opening of the arc-shaped plate. The high-pressure chamber is circulated with an airflow that can blow the rapeseed seeds located in the Bessel-type holes at the high-pressure chamber outward. The seeding pipe is located at the bottom of the arc-shaped plate, with its upper opening connected to the opening of the arc-shaped plate and its lower opening connected to the outside.

7. The seed metering device for rapeseed according to claim 6, characterized in that, Both ends of the rotating shaft are fitted with end caps in the gap outside the seeding roller. The end caps are fixedly installed on the corresponding side plates of the cover. The high-pressure chamber is fixedly installed on the end caps.

8. The seed metering device for rapeseed according to claim 6, characterized in that, The opening of the arc-shaped plate is wide enough in the circumferential direction to completely cover 2-5 seed filling holes.

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