Pressure reduction structure of positive pressure seed meter

Abstract

This invention discloses a pressure loss reduction structure for a positive pressure seed metering device. The space enclosed by the front and rear shells of the positive pressure seed metering device is divided into a front cavity and a rear cavity by a seed metering disc. An airtight cover and a pressure relief wheel are installed in the rear cavity. The airtight cover has a central hole, and a first sealing element is provided between its outer edge and the edge of the seed metering disc. The airtight cover can rotate with the seed metering disc, and its central hole is connected to the rear shell via a bearing. A first sealing ring and a second sealing ring are respectively provided between the inner and outer rings of the bearing and the rear shell and the airtight cover. The mounting bracket connected to the pressure relief wheel has a fan-shaped connecting part, on which an arc-shaped windbreak is fixed. In the direction of movement of the seed suction holes on the seed metering disc, the windbreak is located behind the pressure relief wheel and can block the back side of the seed suction holes within its arc length range. In this invention, a dual measure is adopted to avoid pressure loss, which can significantly reduce wind pressure loss, reduce the required positive pressure airflow pressure, and maintain the stability of the suction force of the seed suction holes.

Description

Technical Field

[0001] This invention relates to the field of seed metering technology, and in particular to a pressure reduction structure for a positive pressure seed metering device. Background Technology

[0002] In the field of precision seeding in agriculture, positive pressure seed metering devices use the pressure difference generated by positive pressure airflow to adsorb seeds onto the suction holes of the seed metering disc, thereby achieving precise seed picking and metering. To maintain the stability of the suction force at the suction holes, the sealing performance of the air chamber inside the seed metering device is crucial.

[0003] In current technologies, such as the utility model patent CN219395501U, an air-sealing structure for a circular fixed base and a circular seed-dispensing tray is disclosed. This structure primarily achieves sealing by creating an annular groove on the inner surface of the fixed base and embedding an air-sealing rubber ring, utilizing the tight compression between the rubber ring and the inner end face of the seed-dispensing tray. However, this structure represents a large-diameter dynamic sealing method. During operation, the frequent friction between the seed-dispensing tray and the rubber ring significantly increases the running resistance of the seed-dispensing tray and causes rapid wear of the rubber ring, affecting the seal's lifespan.

[0004] More importantly, the aforementioned existing technologies generally focus on the circumferential sealing of the seed metering disc's edge, but neglect the additional air pressure loss caused by the suction holes in the non-working area (i.e., between the seed metering area and the seed suction area). Since these suction holes remain open during operation, they continuously release pressure and consume a large amount of positive pressure airflow, leading to increased fan energy consumption and fluctuations in suction pressure, thus affecting the operational stability of the seed metering device. Existing technologies include sealing solutions for air-suction (negative pressure) seed metering devices. For example, utility model patent CN216218713U discloses a negative pressure chamber sealing ring. By setting a support ring with a working plane, a sealed negative pressure chamber is formed with the seed metering disc. The function of this sealing ring is to limit the negative pressure suction force within a specific arc-shaped working range. However, there is currently no solution in the existing technology for how to generate suction force in the suction holes within a certain range in a positive pressure seed metering device, while preventing pressure release in the suction holes in the non-working area. Summary of the Invention

[0005] Purpose of the invention: In order to overcome the shortcomings of the existing technology, the present invention provides a pressure loss reduction structure for a positive pressure seed metering device.

[0006] Technical Solution: To achieve the above objectives, the positive pressure seed metering device of the present invention has a pressure reduction structure, which is applied to a positive pressure seed metering device having a front shell, a seed metering disc, a pressure relief wheel, and a rear shell. The space enclosed by the front shell and the rear shell of the positive pressure seed metering device is separated into a front cavity and a rear cavity by the seed metering disc. The front shell has an air inlet for introducing positive pressure airflow into the front cavity. An airtight cover and a pressure relief wheel are installed in the rear cavity. The airtight cover has a central hole, and a first sealing element is provided between its outer edge and the edge of the seed metering disc.

[0007] The airtight cover can rotate with the seeding disc, and its central hole is connected to the rear shell through a bearing; the inner and outer rings of the bearing are respectively provided with a first sealing ring and a second sealing ring between the rear shell and the airtight cover; the bearing is a bearing with a sealing cover between the inner and outer rings.

[0008] The mounting bracket connected to the pressure relief wheel has a fan-shaped connecting part, and an arc-shaped windbreak is fixed on it; in the direction of movement of the seed suction hole on the seed metering disc, the windbreak is located on the rear side of the pressure relief wheel and can block the back side of the seed suction hole within its arc length range.

[0009] When the positive pressure seed metering device is in operation, under the action of positive pressure airflow, the seed suction hole generates suction force, sucking out the seeds from the seed pile at the bottom of the front chamber and transporting the seeds to the position of the pressure relief wheel. The pressure relief wheel first blocks the seed suction hole, so that the pressure of the seed suction hole disappears, and the seeds sucked by the seed suction hole fall off to complete the seed metering. After the seed metering, the seed suction hole enters the working area of ​​the wind deflector. Within the arc range of the wind deflector, the back side of the seed suction hole is blocked until the seed suction hole reaches the vicinity of the bottom of the front chamber again and leaves the working range of the wind deflector to generate suction force again.

[0010] Furthermore, the rear housing has an annular portion extending into the rear cavity in the middle; the bearing is sleeved on the annular portion; the mounting bracket is fixed to the end of the annular portion, and the mounting bracket abuts against the inner ring of the bearing; the first sealing ring is located at the junction of the annular portion, the mounting bracket, and the inner ring of the bearing.

[0011] Furthermore, one end of the outer ring of the bearing abuts against the limiting step in the intermediate hole, and the end of the airtight cover is fixed with a pressure plate that abuts against the other end of the outer ring; the second sealing ring is placed in the annular groove in the intermediate hole and contacts the pressure plate.

[0012] Furthermore, the first sealing member has a fixing part and a tapered first sealing lip that is turned outward from the fixing part; the end face of the outer edge of the airtight cover has an annular groove for the fixing part to be inserted; the first sealing lip contacts the back edge of the seed metering tray.

[0013] Furthermore, a second sealing element is provided at the joint between the front shell and the rear shell. The second sealing element has a sleeve fixing part and a conical second sealing lip that is turned outward from the end of the sleeve fixing part. The end face of the rear shell has an outwardly protruding annular part for the sleeve fixing part to be sleeved. The second sealing lip contacts the inner wall of the front shell.

[0014] There are gaps between the edge of the seed metering disc and the front and rear shells, and the first and second sealing elements are placed on opposite sides of the gaps. Both the first and second sealing lips are flexible.

[0015] Furthermore, the fan-shaped connecting part has a fan-shaped body and a curved flange, and the edge of the curved flange has multiple connecting parts arranged in a dispersed manner; the windproof member has a number of sleeve parts that are matched one-to-one with the connecting parts.

[0016] Furthermore, the main body of the windshield has an arc-shaped groove on its end face.

[0017] Beneficial effects: The air pressure reduction structure of the positive pressure seed metering device of the present invention has the following beneficial effects:

[0018] (1) In this invention, two measures are adopted to avoid air pressure loss. The first measure is the sealing treatment around the airtight cover, which forms a sealed space between the airtight cover and the rear shell to prevent air pressure from leaking out from the edge of the seed metering tray. The dynamic sealing treatment method of fixing the airtight cover in the prior art CN219395501U will increase the running resistance of the seed metering tray and cause frequent wear of the rubber ring. In contrast, this invention adopts a static sealing form in which the airtight cover rotates with the seed metering tray, and uses the bearing sealing cover and two sealing rings at the inner and outer rings of the bearing for dynamic sealing near the bearing. This can avoid increasing the rotational resistance of the seed metering tray, and the sealing part has a small diameter, which significantly reduces the sealing difficulty. The second measure is to block the back side of the seed suction hole in the middle area between the seed metering area and the seed suction area to prevent the pressure of the seed suction hole in this part from leaking and causing additional air pressure loss. Based on the above two measures, the air pressure loss can be greatly reduced, the required positive pressure airflow pressure can be reduced, and the stability of the suction force of the seed suction hole can be maintained, thus improving the operating stability of the seed meterer.

[0019] (2) The structural design of the first and second sealing elements allows air pressure to press the first and second sealing lips tightly against the respective wall surfaces they are attached to, preventing air leakage and ensuring airtightness. In addition, the front and rear shells do not require precise fitting to achieve a seal at the joint, which can reduce the difficulty of disassembly and assembly.

[0020] (3) The connection structure between the wind deflector and the mounting frame is reasonably designed, which makes it easy to fix the wind deflector stably and reduces the installation difficulty. The arc groove design on the wind deflector can ensure the sealing effect while reducing the frictional resistance with the seed metering tray.

[0021] (4) The windshield and the pressure relief wheel share the same mounting bracket, which can reduce the number of parts and reduce the structural complexity. Attached Figure Description

[0022] Figure 1 This is an exploded structural diagram of a positive pressure seed metering device;

[0023] Figure 2 This is a cross-sectional view of a positive pressure seed metering device;

[0024] Figure 3 for Figure 2 Enlarged structural diagram of section A;

[0025] Figure 4 for Figure 2 Enlarged structural diagram of section B;

[0026] Figure 5 This is a structural diagram of the combined structure of the mounting bracket, pressure relief wheel, and wind deflector.

[0027] In the diagram: 1-front shell; 2-seed metering disc; 2a-seed suction hole; 3-pressure relief wheel; 4-rear shell; 4a-annular part; 4b-outer convex ring; 5-airtight cover; 5a-central hole; 6-first seal; 6a-fixing part; 6b-first sealing lip; 7-bearing; 8-first sealing ring; 9-second sealing ring; 10-mounting bracket; 10a-fan-shaped connecting part; a-bent flange; 10b-support arm; 11-wind baffle; 11a-sleeve part; 11b-arc groove; 12-pressure plate; 13-second seal; 13a-sleeve fixing part; 13b-second sealing lip. Detailed Implementation

[0028] The invention will now be further described with reference to the accompanying drawings.

[0029] The pressure loss reduction structure of this invention is applied to, for example... Figure 1 and Figure 2 The positive pressure seed metering device shown has a front shell 1, a seed metering disc 2, a pressure relief wheel 3, and a rear shell 4. The space enclosed by the front shell 1 and the rear shell 4 is separated into a front cavity and a rear cavity by the seed metering disc 2. The front shell 1 has an air inlet for introducing positive pressure airflow into the front cavity. An airtight cover 5 and a pressure relief wheel 3 are installed in the rear cavity. The airtight cover 5 has a central hole 5a, and a first sealing element 6 is provided between its outer edge and the edge of the seed metering disc 2. The internal space of the airtight cover 5 is in communication with the atmosphere.

[0030] The airtight cover 5 can rotate with the seed metering disc 2, and its central hole 5a is connected to the rear shell 4 via a bearing 7; Figure 4 As shown, the inner and outer rings of the bearing 7 are respectively provided with a first sealing ring 8 and a second sealing ring 9 between them and the rear housing 4 and the airtight cover 5; the bearing 7 is a bearing with a sealing cover between the inner and outer rings.

[0031] The mounting bracket 10 connected to the pressure relief wheel 3 has a fan-shaped connecting part 10a, on which an arc-shaped windbreak 11 is fixed. The pressure relief wheel 3 is mounted on a support arm 10b independent of the fan-shaped connecting part 10a. In the direction of movement of the seed suction hole 2a on the seed metering disc 2, the windbreak 11 is located on the rear side of the pressure relief wheel 3 and can block the back side of the seed suction hole 2a within its arc length range.

[0032] When the positive pressure seed metering device is in operation, under the action of positive pressure airflow, the seed suction hole 2a generates suction force, sucking out the seeds from the seed pile at the bottom of the front chamber and transporting the seeds to the position of the pressure relief wheel 3. The pressure relief wheel 3 first blocks the seed suction hole 2a, so that the pressure of the seed suction hole 2a disappears, and the seeds adsorbed by the seed suction hole 2a fall off to complete the seed metering. After the seed metering, the seed suction hole 2a enters the working area of ​​the wind deflector 11. Within the arc range of the wind deflector 11, the back side of the seed suction hole 2a is blocked until the seed suction hole 2a reaches the vicinity of the bottom of the front chamber again and leaves the working range of the wind deflector 11 to generate suction force again.

[0033] In this invention, two measures are employed to avoid air pressure loss. The first measure is a sealing treatment around the airtight cover 5, which creates a sealed space between the airtight cover 5 and the rear shell 4, preventing air pressure from leaking out from the edge of the seed metering disc 2. Existing technologies using a dynamic sealing method with a fixed airtight cover increase the operating resistance of the seed metering disc and cause frequent wear of the rubber rings. In contrast, this invention uses a static sealing method where the airtight cover 5 rotates with the seed metering disc 2, and a dynamic sealing method near the bearing 7 using the bearing's sealing cover and two sealing rings at the inner and outer rings of the bearing. This avoids increasing the rotational resistance of the seed metering disc 2, and the sealing part has a small diameter, significantly reducing the sealing difficulty. The second measure is to block the back side of the seed suction hole 2a located in the middle area between the seed metering zone and the seed suction zone, preventing pressure leakage from this part of the seed suction hole 2a and causing additional air pressure loss. Based on these two measures, air pressure loss can be significantly reduced, the required positive pressure airflow can be lowered, and the stability of the suction force of the seed suction hole 2a can be maintained, thus improving the operational stability of the seed meterer.

[0034] Preferably, the rear housing 4 has an annular portion 4a extending into the rear cavity in its middle portion; the bearing 7 is sleeved on the annular portion 4a; the mounting bracket 10 is fixed to the end of the annular portion 4a, and the mounting bracket 10 abuts against the inner ring of the bearing 7; the first sealing ring 8 is located at the junction of the annular portion 4a, the mounting bracket 10, and the inner ring of the bearing 7. This structure, by providing the annular portion 4a and utilizing the mounting bracket 10 to press against the inner ring of the bearing 7, achieves a compact integration of the bearing 7 and the mounting bracket 10. Simultaneously, the first sealing ring 8, placed at the junction of the annular portion 4a, the mounting bracket 10, and the inner ring of the bearing 7, forms a highly efficient multi-faceted sealing system, strictly preventing high-pressure airflow leakage from the installation gap.

[0035] Preferably, one end of the outer ring of the bearing 7 abuts against the limiting step in the intermediate hole 5a, and the end of the airtight cover 5 is fixed with a pressure plate 12 that abuts against the other end of the outer ring; the second sealing ring 9 is placed in the annular groove in the intermediate hole 5a and contacts the pressure plate 12.

[0036] Preferably, the first sealing member 6 has a fixing part 61 and a conical first sealing lip 6b that is turned outward from the fixing part 6a; the end face of the outer edge of the airtight cover 5 has an annular groove for the fixing part 6a to be inserted; the first sealing lip 6b contacts the back edge of the seeding tray 2.

[0037] Preferably, such as Figure 3 As shown, a second sealing member 13 is provided at the joint between the front shell 1 and the rear shell 4. The second sealing member 13 has a sleeve fixing part 13a and a conical second sealing lip 13b that is turned outward from the end of the sleeve fixing part 13a. The end face of the rear shell 4 has an outwardly protruding ring 4b for the sleeve fixing part 13a to be sleeved. The second sealing lip 13b is in contact with the inner wall of the front shell 1.

[0038] There are gaps between the edge of the seed metering disc 2 and the front shell 1 and the rear shell 4, and the first sealing element 6 and the second sealing element 13 are placed on both sides of the gap. Both the first sealing lip 6b and the second sealing lip 13b are flexible.

[0039] The structural design of the first sealing element 6 and the second sealing element 13 allows air pressure to press the first sealing lip 6b and the second sealing lip 13b tightly against the wall surface they are attached to, preventing air leakage and ensuring airtightness. In addition, the front shell 1 and the rear shell 4 do not require precise fitting to achieve a seal at the joint, which can reduce the difficulty of disassembly and assembly.

[0040] Preferably, such as Figure 5 As shown, the fan-shaped connecting part 10a has a fan-shaped body and a curved flange a, and the edge of the curved flange a has multiple connecting parts arranged in a dispersed manner; the windproof member 11 has a number of sleeve parts 11a that are in equal and corresponding fit with the connecting parts.

[0041] Preferably, the end face of the main body of the windbreak 11 has an arc-shaped groove 11b.

[0042] The connection structure between the wind deflector 11 and the mounting bracket 10 is reasonably designed, facilitating stable fixation of the wind deflector 11 and reducing installation difficulty. The arc-shaped groove 11b on the wind deflector 11 ensures the sealing effect while reducing frictional resistance with the seed metering disc 2. The wind deflector 11 and the pressure relief wheel 3 share the same mounting bracket 10, which reduces the number of parts and lowers structural complexity.

[0043] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A pressure reduction structure for a positive pressure seed metering device, wherein the space enclosed by the front shell (1) and the rear shell (4) of the positive pressure seed metering device is separated into a front cavity and a rear cavity by a seed metering disc (2); the front shell (1) has an air inlet for introducing positive pressure airflow into the front cavity; an airtight cover (5) and a pressure relief wheel (3) are installed in the rear cavity; the airtight cover (5) has a central hole (5a), and a first sealing element (6) is provided between its outer edge and the edge of the seed metering disc (2); Its features are: The airtight cover (5) can rotate with the seeding tray (2), and its middle hole (5a) is connected to the rear shell (4) through a bearing (7); the inner and outer rings of the bearing (7) are respectively provided with a first sealing ring (8) and a second sealing ring (9) between the rear shell (4) and the airtight cover (5). The mounting bracket (10) connected to the pressure relief wheel (3) has a fan-shaped connecting part (10a), and an arc-shaped windproof member (11) is fixed on it; in the direction of movement of the seed suction hole (2a) on the seed metering disc (2), the windproof member (11) is located on the rear side of the pressure relief wheel (3) and can block the back side of the seed suction hole (2a) within its arc length range.

2. The air pressure reduction structure of the positive pressure seed metering device according to claim 1, characterized in that, The rear housing (4) has an annular portion (4a) extending into the rear cavity in the middle; the bearing (7) is sleeved on the annular portion (4a); the mounting bracket (10) is fixed to the end of the annular portion (4a) and the mounting bracket (10) abuts against the inner ring of the bearing (7); the first sealing ring (8) is located at the junction of the annular portion (4a), the mounting bracket (10) and the inner ring of the bearing (7).

3. The air pressure reduction structure of the positive pressure seed metering device according to claim 1, characterized in that, One end of the outer ring of the bearing (7) abuts against the limiting step in the intermediate hole (5a), and the end of the airtight cover (5) is fixed with a pressure plate (12) that abuts against the other end of the outer ring; the second sealing ring (9) is placed in the annular groove in the intermediate hole (5a) and contacts the pressure plate (12).

4. The air pressure reduction structure of the positive pressure seed metering device according to claim 1, characterized in that, The first sealing member (6) has a fixing part (61) and a tapered first sealing lip (6b) that is turned outward from the fixing part (6a); the end face of the outer edge of the airtight cover (5) has an annular groove for the fixing part (6a) to be inserted; the first sealing lip (6b) contacts the back edge of the seeding tray (2).

5. The air pressure reduction structure of the positive pressure seed metering device according to claim 1, characterized in that, A second sealing element (13) is provided at the joint between the front shell (1) and the rear shell (4). The second sealing element (13) has a sleeve fixing part (13a) and a conical second sealing lip (13b) that is turned outward from the end of the sleeve fixing part (13a). The end face of the rear shell (4) has an outwardly protruding ring (4b) for the sleeve fixing part (13a) to be sleeved. The second sealing lip (13b) is in contact with the inner wall of the front shell (1).

6. The air pressure reduction structure of the positive pressure seed metering device according to claim 1, characterized in that, The fan-shaped connecting part (10a) has a fan-shaped body and a curved flange (a), and the edge of the curved flange (a) has multiple connecting parts arranged in a dispersed manner; the windproof member (11) has a number of sleeve parts (11a) that are in one-to-one correspondence with the connecting parts.

7. The air pressure reduction structure of the positive pressure seed metering device according to claim 1, characterized in that, The windbreak (11) has an arc-shaped groove (11b) on the end face of the main body.

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