Air suction type precision seed sowing device based on coaxial transmission

Abstract

The invention relates to the field of agricultural machinery, in particular to an air suction type precision seed sowing device based on coaxial transmission. Comprising an air-suction type seed metering mechanism and a seed guiding mechanism which are connected through a planetary gear mechanism, a planet carrier of the planetary gear mechanism is fixedly connected with a seed suction disc of the air suction type seed metering mechanism, and a sun gear of the planetary gear mechanism is fixedly connected with a seed guide belt wheel of the seed guide mechanism; the seed suction ports of the seed suction disc and the seed guide belt have the same linear speed, and the distance between the two adjacent seed suction ports on the seed suction disc is equal to the distance between the two adjacent seed guide partition plates on the seed guide belt. Only one power input shaft is needed to simultaneously drive the seed suction disc and the seed guide belt wheel to coaxially and differentially rotate, the rotating speed ratio of the seed suction disc to the seed guide belt wheel can be strictly controlled, the radius ratio of the seed suction disc to the seed guide belt wheel is designed, so that the linear speed of a seed suction opening is the same as that of a seed guide belt, seeds adsorbed on the seed suction disc can be accurately transferred to the seed guide belt, and the seed suction disc is prevented from being damaged. The seed guide belt conveys the seeds to the ground all the time, so that precise seeding is realized.

Description

Technical Field

[0001] The present invention relates to the field of agricultural machinery, in particular to an air-suction precision seed metering device based on coaxial transmission. Background Art

[0002] Sowing is a key step in the crop planting process, directly related to the final crop yield. Mechanical sowing not only improves sowing efficiency but also improves sowing quality. The realization of mechanized precision sowing of crops has become an inevitable trend.

[0003] As the core working component of the seeder, various types of seeders have been developed, such as spoon type, finger clamp type, spoon clamp type, etc. They have certain defects in performance and structure: the spoon type seeder is not suitable for high-speed sowing and has poor vibration resistance; the finger clamp type and spoon clamp type seeders have serious parts wear and tear, and require a high-power drive unit; the air suction type seeder performs well in high-speed operation, no seed damage, and low missed seeding rate, and has gradually become an important development direction of precision seeding technology.

[0004] The pneumatic seed metering mechanism operates by creating a negative pressure in the suction chamber housing through an air suction pipe. As the seed tray rotates and passes over the seeds in the seed box, the negative pressure causes the seeds to be attracted to the tray's suction opening. As the tray continues to rotate, the suction opening, holding the seeds, moves out of the negative pressure zone. Gravity forces the seeds to fall from the suction opening and into the seed guide, completing the seed metering process.

[0005] The air-suction seeder without a seed guide belt uses a seed guide tube to transport seeds. There is no constraint on the seeds during their falling process, and the seed placement is not accurate enough. Although the air-suction seeder with a seed guide belt can constrain the falling process of seeds, it requires multiple power inputs during actual operation and it is difficult to ensure that the rotation speed of the seed suction disc and the seed guide pulley is accurately matched. A larger space is required to install the seed guide device, and the installation space on the agricultural machinery is limited, which is not conducive to the compact design of the equipment. Summary of the Invention

[0006] The purpose of the present invention is to overcome the above-mentioned defects in the prior art and propose an air-suction precision seed metering device based on coaxial transmission, which has a stable working process, small error, and is convenient for achieving precise sowing.

[0007] The technical solution of the present invention is: an air-suction precision seed metering device based on coaxial transmission, which includes an air-suction seed metering mechanism and a seed guiding mechanism, and the air-suction seed metering mechanism and the seed guiding mechanism are connected by a planetary gear mechanism; The planetary carrier of the planetary gear mechanism is fixedly connected to the seed suction disc of the air suction seeding mechanism, and the sun gear of the planetary gear mechanism is fixedly connected to the seed guide pulley of the seed guide mechanism; The linear speeds of the seed suction port of the seed suction disc and the seed guide belt are the same, and the distance between two adjacent seed suction ports on the seed suction disc is equal to the distance between two adjacent seed guide partitions on the seed guide belt.

[0008] In the present invention, the air suction seeding mechanism includes: The suction chamber shell has an air intake port on its upper part and an annular negative pressure cavity inside thereof, the negative pressure cavity is connected to the air intake port, and the air intake port is connected to the negative pressure fan; A seed chamber shell, the upper portion of which is provided with a seed inlet; The seed suction tray is located in the cavity formed by the suction chamber shell and the seed chamber shell. One side of it is a negative pressure cavity and the other side is a seed inlet. A sealing ring is provided between the seed suction tray and the negative pressure cavity, and several seed suction ports are evenly spaced along the circumferential edge of the seed suction tray.

[0009] The seed guide mechanism includes an annular seed guide belt arranged in the vertical direction, the upper end of which is wound around the seed guide belt wheel, and the lower end of which is wound around the seed guide belt driven wheel; Several seed guide partitions are evenly spaced along the length of the seed guide belt; The sides of the seed guide belt fit into the sides of the seed suction disc.

[0010] The planetary gear mechanism includes: The gear ring is annular and fixed in the reserved space in the middle of the suction chamber shell through interference fit, and its inner surface is provided with an internal gear; The sun gear is located at the center of the ring gear and is fixedly connected to the central axis of the seed guide pulley; Several planetary gears are arranged between the annular outer side of the sun gear and the annular inner wall of the ring gear. The planetary gears mesh with the inner teeth of the ring gear and the sun gear at the same time.

[0011] The planetary gear mechanism also includes a planet carrier; The planetary frame is provided with several support columns, each of which is rotatably connected to the center of the planetary wheel. The corresponding seed suction disc is provided with several fixed connection holes, and the end of each support column passes through the fixed connection hole and is fixedly connected to the seed suction disc. The center of the planet carrier is rotatably connected to the sun gear; The center of the planet carrier away from the sun gear is connected to the input shaft.

[0012] As the input shaft rotates, the planetary gears are driven to revolve around the sun gear through the planet carrier, and the sun gear is driven to rotate through the meshing of the gears between the planetary gears and the sun gear; The planet carrier drives the seed suction disc to rotate, and the rotation speed of the seed suction disc is equal to that of the planet carrier; the sun gear drives the seed guide pulley to rotate, and the rotation speed of the sun gear and the seed guide pulley is equal.

[0013] By setting the gear ratio of the planetary gear to the sun gear, the speed ratio between the planet carrier and the sun gear is determined to be 1:n; The ratio of the distance from the seed suction port of the seed suction disc to the center of the seed suction disc to the radius of the seed guide pulley is n:1, thereby ensuring that the linear speed of the seed suction port of the seed suction disc and the seed guide pulley is the same.

[0014] The seeds that enter the air-suction seeding mechanism through the seed inlet are adsorbed at the seed suction port under the action of negative pressure. As the seed suction disc rotates, when the seed suction port is in the negative pressure area, the seeds are always adsorbed at the seed suction port. When the seed suction disc rotates to the seed suction port and enters the non-negative pressure area, the seeds move along a certain trajectory under the action of gravity and fall onto the corresponding seed guide partition; As the seed suction disc and the seed guide belt rotate, the seeds adsorbed on each seed suction port fall into the adjacent seed guide partitions in turn.

[0015] One end of the central shaft of the seed guide pulley is fixedly connected to the sun gear, and the other end of the central shaft of the seed guide pulley is fixedly connected to the seed guide belt pulley; the central shaft of the seed guide pulley passes through the central hole of the seed suction disc.

[0016] The seed guiding mechanism also includes a seed guiding shield, which is arranged on the outside of the seed guiding belt and the seed guiding partition; The seed guide belt driven wheel and the seed guide shield are rotationally connected; Arc-shaped guide plates are respectively arranged on the two outer sides below the seed guide belt. The two guide plates are symmetrically arranged and fixed on the guide shield.

[0017] The beneficial effects of the present invention are: (1) By introducing the planetary gear mechanism, the planetary carrier is used as the only power input component, which can not only drive the seed suction disc to rotate, but also drive the sun gear to rotate through the planetary gear, thereby driving the seed guide pulley to rotate. Through the same power input component, the seed suction disc and the seed guide pulley are driven to rotate at the same time, ensuring the movement stability of the entire machine. Compared with using two motors and two power input shafts to drive the seed suction disc and the seed guide pulley respectively, the machine is more stable and can reduce the error in the process of mutual coordination; (2) Since the seed suction disc and the seed guide pulley in the present application are driven by the same power input component, it is very convenient to achieve the same linear speed of the seed suction port of the seed suction disc and the seed guide belt; under the premise that the seed suction port of the seed suction disc and the seed guide belt have the same linear speed, the distance between two adjacent seed suction ports is equal to the distance between two adjacent seed guide partitions, which fully ensures that during the rotation of the seed suction disc, each seed falling from the seed suction port can fall into the adjacent seed guide partitions in sequence, thereby achieving precise seed placement control; (3) The seeds that fall into the seed guide partition move downward at a uniform speed to the ground along the seed guide belt. The seeds in each seed guide partition fall into the soil separately, achieving precise sowing.

[0018] To sum up, the present application only needs one power input shaft to simultaneously drive the seed suction disc and the seed guide pulley to rotate coaxially and differentially, which can strictly control the speed ratio of the seed suction disc and the seed guide pulley, and by designing the radius ratio of the seed suction disc and the seed guide pulley, the linear speed of the seed suction port and the seed guide belt is made the same, the seeds adsorbed on the seed suction disc can be accurately transferred to the seed guide belt, and the seed guide belt transports the seeds all the way to the ground to achieve precise sowing. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a structural schematic diagram of the present invention; Figure 2 It is an exploded view of the structure of the present invention; Figure 3 Schematic diagram of the structure of the seed suction tray and the seed guide mechanism in the present invention; Figure 4 Schematic diagram of the main structure of the planetary gear mechanism of the present invention; Figure 5 It is a rear structural schematic diagram of the planetary gear mechanism of the present invention.

[0020] Among them, 1 input shaft; 2 planetary gear mechanism; 2-1 planetary carrier; 2-2 ring gear; 2-3 planetary gear 2-4 sun gear; 3 suction chamber housing; 3-1 suction port; 3-2 negative pressure chamber; 4 bearing; 5 sealing ring; 6 seed suction disc; 6-1 seed suction port; 7 seed cleaning knife; 8 seed guide shield; 9 seed guide pulley; 10 seed guide belt driven pulley; 11 seed guide belt; 12 seed guide partition; 13 seed chamber housing; 13-1 seed inlet. DETAILED DESCRIPTION

[0021] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0022] The following description sets forth specific details to facilitate a thorough understanding of the present invention. However, the present invention can be implemented in a variety of other ways than those described herein, and those skilled in the art will be able to make similar generalizations without departing from the scope of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0023] like Figure 1 and Figure 2 As shown, the pneumatic precision seed metering device based on coaxial transmission described in the present invention includes an pneumatic seed metering mechanism and a seed guiding mechanism, and the pneumatic seed metering mechanism and the seed guiding mechanism are connected by a planetary gear mechanism.

[0024] The air-suction seeding mechanism includes a housing and a seed suction disc 6 disposed within the housing. The housing includes a suction chamber housing 3 and a seed chamber housing 13, which are fixedly connected by bolts, forming a cavity inside the suction chamber housing 3 and the seed chamber housing 13, and the seed suction disc 6 is located in the cavity.

[0025] An annular negative pressure chamber 3-2 is provided within the suction chamber housing 3. An air inlet 3-1 is provided at the top of the suction chamber housing 3, communicating with the negative pressure chamber 3-2. The air inlet 3-1 is connected to a negative pressure blower to create a negative pressure region within the negative pressure chamber 3-2, thereby attracting the crop seeds to the seed suction tray 6 through the negative pressure.

[0026] A circular space is reserved in the middle of the suction chamber housing 3, and the planetary gear mechanism is arranged in the circular space.

[0027] The upper portion of the seed chamber housing 13 is provided with a seed inlet 13 - 1 , through which crop seeds enter the interior of the air-suction seed-dispensing mechanism. The seed inlet 13 - 1 is communicated with the seed suction tray 6 .

[0028] One side of the seed suction disc 6 is the negative pressure chamber 3-2, and the other side of the seed suction disc 6 is the seed inlet 13-1. A sealing ring 5 is provided between the negative pressure chamber 3-2 and the seed suction disc 6, which ensures the sealing of the negative pressure chamber 3-2 and facilitates maintaining a negative pressure state in the negative pressure chamber 3-2.

[0029] Several seed suction openings 6-1 are evenly spaced along the edge of the periphery of the seed suction tray 6. In the present embodiment, the seed suction tray 6 is a circular disk, so several seed suction openings are evenly spaced along the circumferential edge of the seed suction tray 6.

[0030] A negative pressure seed suction area is formed in the cavity composed of the suction chamber shell 3 and the seed chamber shell 13 through the negative pressure cavity 3-2. The negative pressure seed suction area is located in the annular area in the middle and upper part of the cavity. Therefore, after the crop seeds enter the cavity through the seed inlet 13-1, the seeds are adsorbed on the seed suction port 6-1 under the action of negative pressure.

[0031] In the negative pressure area, the crop seeds are adsorbed on the seed suction port 6-1. When the seed suction disc 6 rotates until the seed suction port enters the non-negative pressure area, the crop seeds on the seed suction port move along a certain trajectory under the action of gravity and fall directly into the seed guide mechanism.

[0032] The seed suction tray 6 is provided with a seed cleaning knife 7. The seed cleaning knife 7 is set to two gears: when the seed suction tray 6 carries seeds and passes through the seed cleaning knife 7 in the first gear, the seed cleaning knife 7 can clear the excess seeds adsorbed by the seed suction tray 6 back to the seed inlet 13-1, ensuring that each seed suction port 6-1 only adsorbs one seed; when sowing is stopped, the seed cleaning knife 7 is adjusted to the second gear, at which time the seed cleaning knife 7 can clear all the seeds adsorbed on the seed suction tray 6 back to the seed inlet 13-1.

[0033] like Figure 2 and Figure 3As shown, the seed guide mechanism includes an annular seed guide belt 11, which is arranged in a vertical direction. The upper end of the seed guide belt 11 is wrapped around the seed guide pulley 9, and the lower end of the seed guide belt 11 is wrapped around the seed guide belt driven pulley 10. During the rotation of the seed guide pulley 9, the seed guide belt 11 is driven to move, and the seed guide belt driven pulley 10 also rotates accordingly, playing a guiding role. Several seed guide partitions 12 are evenly spaced along the outer surface of the seed guide belt 11 along its length. The side of the seed guide belt 11 is in contact with the side wall of the seed suction disk 6 to prevent the formation of a gap between the seed guide belt 11 and the seed suction disk 6, which may cause the seeds to get stuck or even leak.

[0034] The seed guide mechanism in this embodiment also includes a seed guide shield 8, which is located outside the seed guide belt 11 and seed guide partition 12 and forms a seed guide chamber with the seed guide belt 11 and seed guide partition 12. A seed guide belt driven pulley 10 is rotatably mounted on the seed guide shield 8. Furthermore, curved deflectors are symmetrically positioned on either side of the lower end of the seed guide belt 11 and are fixed to the seed guide shield 8. These deflectors ensure that crop seeds falling from the seed guide belt are more accurately deposited into the soil.

[0035] like Figure 2 ,like Figure 4 and Figure 5 As shown, the planetary gear mechanism includes a ring gear 2-2, which is annular and has internal teeth on its inner surface. A sun gear 2-4 is located at the center of the ring gear 2-2. Several planet gears 2-3 are located around the outer ring of the sun gear 2-4. The planet gears 2-3 mesh with both the inner teeth of the ring gear 2-2 and the sun gear 2-3. In this embodiment, four planet gears 2-3 are evenly spaced and arranged around the outer ring of the sun gear 2-4.

[0036] The gear ring 2 - 2 is fixedly installed in the reserved space in the middle of the suction chamber shell 3 through interference fit.

[0037] Planetary gears 2-3 are mounted on planetary carrier 2-1. Several support columns corresponding to the planetary gears are fixed to planetary carrier 2-1. Each support column is rotatably connected to the center of planetary gear 2-3. To prevent direct contact and friction between the support columns and planetary gears 2-3, bearings 4 are installed between the center holes of planetary gears 2-3 and the support columns.

[0038] At the same time, the planetary frame 2-1 is fixedly connected to the seed suction disc 6. The seed suction disc 6 is provided with several fixed connection holes, and the support column on the planetary frame passes through the center of the planetary gear and also passes through the fixed connection holes, thereby realizing the fixed connection between the planetary frame and the seed suction disc.

[0039] The center of the planet carrier 2-1 is rotatably connected to the sun gear 2-4. In this embodiment, the center of the planet carrier 2-1 and the sun gear 2-4 are rotatably connected via a bearing 4, which reduces the friction between the sun gear 2-4 and the planet carrier 2-1.

[0040] At the same time, the sun gear 2-4 is also fixedly connected to the central axis of the seed guide pulley 9, that is, when the sun gear 2-4 rotates, it drives the seed guide pulley 9 to rotate at the same time. One end of the central axis of the seed guide pulley is fixedly connected to the sun gear 2-4, and the other end of the central axis of the seed guide pulley is fixedly connected to the seed guide pulley 9. The central axis of the seed guide pulley passes through the seed suction disc 6.

[0041] The center of the planetary carrier 2-1 is fixedly connected to the input shaft 1. Input shaft 1 is the power input shaft. When input shaft 1 rotates, it drives planetary gears 2-3 to rotate through the support columns of planetary carrier 2-1. At this time, planetary gears 2-3 revolve around sun gear 2-4 and, through the gear meshing between planetary gears 2-3 and sun gear 2-4, drive sun gear 2-4 to rotate. At the same time, the planetary carrier 2-1 also drives the seed suction disc 6 to rotate simultaneously. During the rotation of the seed suction disc 6, the negative pressure within the negative pressure area attracts crop seeds into the seed suction port 6-1. As the seed suction disc 6 rotates, when the seed suction port 6-1 rotates into the non-negative pressure area, the seed suction port 6-1 moves along a specific trajectory under the action of gravity and falls into the seed guide mechanism.

[0042] As sun gear 2-4 rotates, the central axis of the seed guide pulley drives seed guide pulley 9, which in turn drives seed guide belt 10. Seed guide baffles 12 on seed guide belt 10 move with it, causing crop seeds falling from seed suction port 6-1 to fall onto seed guide baffles 12. Seed guide baffles 12 gradually move to the bottom along with seed guide belt 10. When seed guide baffles 12 reach their lowest point and approach the ground, the crop seeds on these baffles fall directly into the soil under the influence of gravity. As seed guide belt 10 continues to rotate, the crop seeds on each baffle fall into the soil in sequence, achieving sequential sowing.

[0043] In order to realize accurate sowing, will guarantee that only one crop seed falls on each seed guiding partition 12. In order to achieve the above-mentioned object, will make the linear speed of the seed suction port 6-1 on the seed suction tray and the seed guiding belt 10 identical.

[0044] By setting the gear ratio between the planetary gear and the sun gear, the speed ratio between the planetary carrier and the sun gear is determined to be 1:n. Since the planetary carrier 2-1 and the seed suction disc 6 rotate at the same speed, and the sun gear and the seed guide pulley 9 rotate at the same speed, to ensure the linear speed of the seed suction disc and the seed guide belt is the same, the ratio of the distance from the seed suction disc to the center of the seed suction disc to the radius of the seed guide pulley is n:1.

[0045] At the same time, the distance between two adjacent seed suction ports 6-1 is equal to the distance between two adjacent seed guide partitions 12. Based on this, while ensuring that the linear speeds of the seed suction port of the seed suction disc and the seed guide pulley are the same, it can also ensure that each crop seed falling from the seed suction port 6-1 can accurately fall on the corresponding seed guide partition 12 in order, which can ensure that crop seeds can fall on each seed guide partition and only one crop seed falls on each seed guide partition, thereby achieving uniform and accurate sowing.

[0046] In this embodiment, when the gear ratio between the planetary gear and the sun gear is 3:2, the speed ratio between the planetary carrier and the sun gear is 1:5, so the distance from the seed suction port 6-1 of the seed suction disc to the center of the seed suction disc is five times the radius of the seed guide pulley.

[0047] The working principle of the device is as follows: when seeds are put into the seed inlet 13-1, the negative pressure fan is turned on and power is input to the planetary frame 2-1, which drives the seed suction disc 6 to rotate clockwise. Due to the existence of negative pressure, the seed suction port 6-1 absorbs the seeds in the seed inlet 13-1.

[0048] When the seed suction disc 6 carries the seeds and passes the seed cleaning knife 7 in the first gear, the seed cleaning knife 7 can clear the excess seeds absorbed by the seed suction disc 6 back to the seed inlet 13-1, ensuring that each seed suction port 6-1 only absorbs one seed. The planetary gear 2-3 is engaged with the sun gear 2-4. When the planetary gear 2-3 rotates clockwise, it drives the sun gear 2-4 to rotate clockwise, and the sun gear 2-4 drives the seed guide pulley 9 to rotate clockwise.

[0049] When seed suction port 6-1 is in the negative pressure area, seeds are attracted to it. When seed suction port 6-1 rotates to the bottom, free of negative pressure, seeds fall from it. Because the distance between adjacent seed guide baffles 12 on seed guide belt 11 is the same as the distance between adjacent seed suction ports 6-1 on seed suction tray 6, each crop seed that falls from seed suction tray 6 is guaranteed to land on its corresponding seed guide baffle 12. The seeds are then transported to the ground by seed guide belt 11 and baffles 12, where they enter the soil evenly and sequentially, achieving precise sowing.

[0050] When stopping sowing, the seed-clearing knife 7 is transferred to the second gear. At this moment, the seed-clearing knife 7 can clear all the seeds adsorbed on the seed-absorbing tray 6 back to the seed inlet 13-1. When there is no seed adsorption on the seed-absorbing tray 6, the seed-dispensing device is closed to complete the sowing operation.

[0051] The above is a detailed introduction to the air suction precision seed metering device based on coaxial transmission provided by the present invention. Specific examples are used herein to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only used to help understand the method of the present invention and its core idea. It should be pointed out that for ordinary technicians in this technical field, without departing from the principles of the present invention, several improvements and modifications can be made to the present invention, and these improvements and modifications also fall within the scope of protection of the claims of the present invention. The above description of the disclosed embodiments enables professionals in this field to implement or use the present invention. Various modifications to these embodiments will be obvious to professionals in this field, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but will conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A pneumatic precision seed metering device based on coaxial transmission, characterized in that: It includes an air-suction seed-discharging mechanism and a seed-guiding mechanism, which are connected via a planetary gear mechanism. The planetary carrier of the planetary gear mechanism is fixedly connected to the seed suction disc of the air suction seeding mechanism, and the sun gear of the planetary gear mechanism is fixedly connected to the seed guide pulley of the seed guide mechanism; The linear speeds of the seed suction port of the seed suction disc and the seed guide belt are the same, and the distance between two adjacent seed suction ports on the seed suction disc is equal to the distance between two adjacent seed guide partitions on the seed guide belt.

2. The air suction precision seed metering device based on coaxial transmission according to claim 1 is characterized in that: The air suction seeding mechanism includes: The suction chamber shell has an air intake port on its upper part and an annular negative pressure cavity inside thereof, the negative pressure cavity is connected to the air intake port, and the air intake port is connected to the negative pressure fan; A seed chamber shell, the upper portion of which is provided with a seed inlet; The seed suction tray is located in the cavity formed by the suction chamber shell and the seed chamber shell. One side of it is a negative pressure cavity and the other side is a seed inlet. A sealing ring is provided between the seed suction tray and the negative pressure cavity, and several seed suction ports are evenly spaced along the circumferential edge of the seed suction tray.

3. The air suction type precision seed metering device based on coaxial transmission according to claim 2 is characterized in that: The seed guide mechanism includes an annular seed guide belt arranged in the vertical direction, the upper end of which is wound around the seed guide belt wheel, and the lower end of which is wound around the seed guide belt driven wheel; Several seed guide partitions are evenly spaced along the length of the seed guide belt; The sides of the seed guide belt fit into the sides of the seed suction disc.

4. The air suction type precision seed metering device based on coaxial transmission according to claim 1 is characterized in that: The planetary gear mechanism includes: The gear ring is annular and fixed in the reserved space in the middle of the suction chamber shell through interference fit, and its inner surface is provided with an internal gear; The sun gear is located at the center of the ring gear and is fixedly connected to the central axis of the seed guide pulley; Several planetary gears are arranged between the annular outer side of the sun gear and the annular inner wall of the ring gear. The planetary gears mesh with the inner teeth of the ring gear and the sun gear at the same time.

5. The air suction type precision seed metering device based on coaxial transmission according to claim 4 is characterized in that: The planetary gear mechanism also includes a planet carrier; The planetary frame is provided with several support columns, each of which is rotatably connected to the center of the planetary wheel. The corresponding seed suction disc is provided with several fixed connection holes, and the end of each support column passes through the fixed connection hole and is fixedly connected to the seed suction disc. The center of the planet carrier is rotatably connected to the sun gear; The center of the planet carrier away from the sun gear is connected to the input shaft.

6. The air suction type precision seed metering device based on coaxial transmission according to claim 5, characterized in that: As the input shaft rotates, the planetary gears are driven to revolve around the sun gear through the planet carrier, and the sun gear is driven to rotate through the meshing of the gears between the planetary gears and the sun gear; The planet carrier drives the seed suction disc to rotate, and the rotation speed of the seed suction disc is equal to that of the planet carrier; the sun gear drives the seed guide pulley to rotate, and the rotation speed of the sun gear and the seed guide pulley is equal.

7. The air suction type precision seed metering device based on coaxial transmission according to claim 1 is characterized in that: By setting the gear ratio of the planetary gear to the sun gear, the speed ratio between the planet carrier and the sun gear is determined to be 1:n; The ratio of the distance from the seed suction port of the seed suction disc to the center of the seed suction disc to the radius of the seed guide pulley is n:1, thereby ensuring that the linear speed of the seed suction port of the seed suction disc and the seed guide pulley is the same.

8. The air suction type precision seed metering device based on coaxial transmission according to claim 7, characterized in that: The seeds that enter the air-suction seeding mechanism through the seed inlet are adsorbed at the seed suction port under the action of negative pressure. As the seed suction disc rotates, when the seed suction port is in the negative pressure area, the seeds are always adsorbed at the seed suction port. When the seed suction disc rotates to the seed suction port and enters the non-negative pressure area, the seeds move along a certain trajectory under the action of gravity and fall onto the corresponding seed guide partition; As the seed suction disc and the seed guide belt rotate, the seeds adsorbed on each seed suction port fall into the adjacent seed guide partitions in turn.

9. The air suction type precision seed metering device based on coaxial transmission according to claim 4, characterized in that: One end of the central shaft of the seed guide pulley is fixedly connected to the sun gear, and the other end of the central shaft of the seed guide pulley is fixedly connected to the seed guide pulley; the central shaft of the seed guide pulley passes through the central hole of the seed suction disc.

10. The air suction type precision seed metering device based on coaxial transmission according to claim 3, characterized in that: The seed guiding mechanism also includes a seed guiding shield, which is arranged on the outside of the seed guiding belt and the seed guiding partition; The seed guide belt driven wheel and the seed guide shield are rotationally connected; Arc-shaped guide plates are respectively arranged on the two outer sides below the seed guide belt. The two guide plates are symmetrically arranged and fixed on the guide shield.

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