A design method of an edge friction driving type block cleaning wheel and a block cleaning device

Abstract

The application provides a design method of an edge friction driving type block cleaning wheel and a block cleaning device. The design method of the edge friction driving type block cleaning wheel comprises the following steps: determining the distance between a friction circle of a seed plate and a circle where suction holes are located according to parameters of the suction holes of the seed plate; calculating the length of a friction arc corresponding to an included angle of adjacent suction holes; determining the number of block cleaning teeth and a draft angle of the block cleaning wheel according to an installation space of the block cleaning wheel and the length of the friction arc; calculating the diameter of the friction circle of the block cleaning wheel according to the length of the friction arc and the number of the block cleaning teeth; calculating the diameter of a circle where the block cleaning teeth are located according to the diameter of the friction circle of the block cleaning wheel, the distance between the friction circle of the seed plate and the circle where the suction holes are located and the draft angle of the block cleaning wheel; determining an included angle between the block cleaning wheel and the seed plate; calculating an included angle between an axis of the block cleaning wheel and the seed plate according to the included angle between the block cleaning wheel and the seed plate and the draft angle of the block cleaning wheel; calculating an included angle between the block cleaning teeth and the axis of the block cleaning wheel according to the included angle between the axis of the block cleaning wheel and the seed plate; determining the structure size and the height h of the block cleaning teeth according to the structure of the suction holes of the seed plate and the diameter, and completing the design.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of seed-metering device, and particularly relates to a design method of an edge friction driving type unblocking wheel and an unblocking device. BACKGROUND

[0002] The pneumatic seed-metering device (including positive pressure and negative pressure seed-metering device) has good seed-metering performance, and gradually replaces the mechanical seed-metering device to become a mainstream product in the market. The seed-metering disc is one of the core components of the pneumatic seed-metering device, and the air flow smoothness of the suction hole on the seed-metering disc is the key to guarantee the seed filling rate. When foreign matter or broken seeds are stuck in the suction hole, the seed-metering device is caused to miss sowing. The unblocking wheel is an important device for preventing the suction hole from being blocked. The unblocking wheel is driven to rotate by means of the uniform unblocking teeth on the outer periphery of the unblocking wheel meshing with the suction hole. The unblocking teeth are sequentially inserted into the suction hole to forcibly push out the blocking objects from the suction hole. The meshing action for a long time causes the unblocking teeth to be seriously worn and the service life of the unblocking teeth to be reduced. SUMMARY

[0003] The present application relates to the technical field of seed-metering device, and particularly relates to a design method of an edge friction driving type unblocking wheel and an unblocking device.

[0004] The technical scheme for solving the above technical problem is as follows: a design method of an edge friction driving type unblocking wheel, comprising the following steps: S1, determining the distance L between the friction circle of the seed-metering disc and the circle where the suction hole is located according to the suction hole parameters of the seed-metering disc; S2, calculating the friction arc length K corresponding to the adjacent suction hole included angle; S3, determining the number N of unblocking teeth and the draft angle B of the unblocking wheel according to the installation space of the unblocking wheel and the friction arc length K; S4, calculating the friction circle diameter φ1 of the unblocking wheel according to the friction arc length K and the number N of unblocking teeth; S5, calculating the circumferential diameter φ2 of the unblocking teeth according to the friction circle diameter φ1 of the unblocking wheel, the distance L between the friction circle of the seed-metering disc and the circle where the suction hole is located, and the draft angle B of the unblocking wheel; S6, determining the included angle A between the unblocking wheel and the seed-metering disc; S7, calculating the included angle C between the axis of the unblocking wheel and the seed-metering disc according to the included angle A between the unblocking wheel and the seed-metering disc and the draft angle B of the unblocking wheel; S8, calculating the included angle D between the unblocking teeth and the axis of the unblocking wheel according to the included angle C between the axis of the unblocking wheel and the seed-metering disc; and S9, determining the structure size and the height h of the unblocking teeth according to the structure and diameter of the suction hole of the seed-metering disc, and completing the design.

[0005] The beneficial effects of the technical scheme of the present application are as follows: the unblocking wheel is driven to rotate by means of the friction between the edge of the unblocking wheel and the seed disc, the wear between the unblocking teeth and the suction hole is avoided, the service life and reliability of the unblocking teeth are improved, and the maintenance cost of the seed-metering device is reduced. The design process of the edge friction driving type unblocking wheel is standardized, the development cycle is shortened, and theoretical support is provided for the design of the unblocking wheel.

[0006] Further, in step S1, the distance L between the friction circle of the seed-metering disc and the circle where the suction hole is located is in the range of 5-15 mm. Step S1 comprises: determining the radius R of the friction circle of the seed-metering disc according to the suction hole parameters of the seed-metering disc.

[0007] The beneficial effect of the further technical solution is that the diameter of the suction hole on the back of the seed plate is generally large to reduce the wind resistance, and the friction circle of the seed plate should not overlap the suction hole to ensure that the seed plate provides sufficient friction force to the cleaning wheel.

[0008] Further, in step S3, the value range of the draft angle B of the cleaning wheel is 0-6°, and the product of the friction arc length K and the number N of the cleaning teeth is the circumference of the friction circle of the cleaning wheel.

[0009] The beneficial effect of the further technical solution is that the friction circle of the cleaning wheel theoretically rolls relative to the friction circle of the seed plate, so the product of the friction arc length K and the number N of the cleaning teeth is the circumference of the friction circle of the cleaning wheel. The value range of the draft angle B of the cleaning wheel is 0-6°, which is convenient for machining.

[0010] Further, in step S4, the diameter φ1 of the friction circle of the cleaning wheel is calculated by the following formula: φ1=N×K / π, wherein φ1 is the diameter of the friction circle of the cleaning wheel, N is the number of cleaning teeth, and K is the friction arc length.

[0011] The beneficial effect of the further technical solution is that the diameter of the friction circle of the cleaning wheel is accurately calculated by the formula, improving accuracy.

[0012] Further, in step S5, the diameter φ2 of the circumference where the cleaning teeth are located is calculated by the following formula: φ2=φ1+2LarctanB, wherein φ2 is the diameter of the circumference where the cleaning teeth are located, φ1 is the diameter of the friction circle of the cleaning wheel, L is the distance between the friction circle of the seed plate and the circle where the suction hole is located, and B is the draft angle of the cleaning wheel.

[0013] The beneficial effect of the further technical solution is that the diameter of the circumference where the cleaning teeth are located is accurately calculated by the formula, improving accuracy.

[0014] Further, in step S6, the value range of the included angle A between the cleaning wheel and the seed plate is 3-10°.

[0015] The beneficial effect of the further technical solution is that the included angle A between the cleaning wheel and the seed plate is determined, and the included angle A is generally 3-10° to ensure the friction force. The included angle A ensures that the cleaning wheel is in contact with the seed plate at the friction line and is not in contact with the seed plate at other parts to prevent deflection force from being generated by multiple parts in contact.

[0016] Further, in step S7, the included angle C between the axis of the cleaning wheel and the seed plate is calculated by the following formula: C=A+B, wherein C is the included angle between the axis of the cleaning wheel and the seed plate, A is the included angle between the cleaning wheel and the seed plate, and B is the draft angle of the cleaning wheel.

[0017] The beneficial effect of the further technical scheme is that the formula is used to accurately calculate the angle between the clear block wheel axis and the seed plate, thereby improving accuracy.

[0018] Further, in step S8, the angle D between the clear block tooth and the clear block wheel axis is calculated by the following formula: D=C+90°, wherein D is the angle between the clear block tooth and the clear block wheel axis, and C is the angle between the clear block wheel axis and the seed plate.

[0019] The beneficial effect of the further technical scheme is that the formula is used to accurately calculate the angle between the clear block tooth and the clear block wheel axis, thereby improving accuracy.

[0020] Further, in step S9, the height h of the clear block tooth is calculated by the following formula according to the suction hole structure, diameter and seed plate thickness H: h=(0.6-1.2)H, wherein H is the seed plate thickness, and h is the height of the clear block tooth.

[0021] The beneficial effect of the further technical scheme is that the formula is used to accurately calculate the height of the clear block tooth, thereby improving accuracy.

[0022] In addition, the application provides an edge friction drive type clear block device, which comprises a clear block wheel, a seed plate, a clear block wheel support, and a spring designed by the design method of the edge friction drive type clear block wheel.

[0023] The beneficial effect of the technical scheme is that the spring is compressed after the seed plate is installed, so that the spring generates a pre-tightening force, which can ensure that the clear block tooth generates an outward ejection force and ensure that the seed plate friction circle and the clear block wheel friction circle are in close contact; when the seed plate rotates around its axis, the seed plate friction circle applies a friction force through the clear block wheel friction circle to drive the clear block wheel to rotate, and then the clear block tooth enters each suction hole of the seed plate in turn; when the suction hole is blocked, the clear block tooth ejects the blockage, thereby completing the hole cleaning.

[0024] The advantages of the additional aspects of the application will be partially given in the following description, partially become obvious from the following description, or be understood through the practice of the application. BRIEF DESCRIPTION OF DRAWINGS

[0025] Figure 1One of the schematic flow block diagrams of the design method of the edge friction driving type blockage cleaning wheel provided by the embodiment of the present application.

[0026] Figure 2 The second schematic flow block diagram of the design method of the edge friction driving type blockage cleaning wheel provided by the embodiment of the present application.

[0027] Figure 3 The schematic diagram of the key parameters of the friction driving type blockage cleaning wheel provided by the embodiment of the present application.

[0028] Figure 4 The structural schematic diagram of the blockage cleaning wheel working system provided by the embodiment of the present application.

[0029] Figure 5 The structural schematic diagram of the matching relationship of the friction driving type blockage cleaning wheel provided by the embodiment of the present application.

[0030] Figure 6 The structural schematic diagram of the seed disc provided by the embodiment of the present application.

[0031] Figure 7 The structural schematic diagram of the blockage cleaning wheel support provided by the embodiment of the present application.

[0032] Figure 8 The structural schematic diagram of the friction driving type blockage cleaning wheel provided by the embodiment of the present application.

[0033] BRIEF DESCRIPTION OF DRAWINGS 1, seed disc; 1.1, suction hole; 1.2, seed disc friction circle; 1.3, seed disc friction arc; 2, blockage cleaning wheel support; 2.1, spring fixing seat; 2.2, support mounting shaft; 2.3, wheel mounting shaft; 3, blockage cleaning wheel; 3.1, blockage cleaning wheel friction circle; 3.2, blockage cleaning tooth; 4, spring; A, included angle between blockage cleaning wheel and seed disc; B, blockage cleaning wheel draft angle; C, included angle between blockage cleaning wheel axis and seed disc; D, included angle between blockage cleaning tooth and blockage cleaning wheel axis; H, seed disc thickness; h, blockage cleaning tooth height; K, friction arc length; L, distance between seed disc friction circle and suction hole; N, number of blockage cleaning teeth; R, seed disc friction circle radius; φ1, blockage cleaning wheel friction circle diameter; φ2, circumference diameter of blockage cleaning tooth. DETAILED DESCRIPTION

[0034] The principles and characteristics of the present application are described below in combination with the drawings, and the embodiments are only used to explain the present application, and are not used to limit the scope of the present application.

[0035] As shown in Figure 1 The embodiment of the present application provides a design method of an edge friction driving type blockage cleaning wheel, which comprises the following steps: S1, determining the distance L between the seed disc friction circle and the suction hole according to the suction hole parameters of the seed disc; S2, calculating the friction arc length K corresponding to the included angle of adjacent suction holes;

[0036] S3, determining the number of the cleaning teeth N and the die drawing angle B of the cleaning wheel according to the installation space of the cleaning wheel and the friction arc length K; S4, calculating the friction circle diameter φ1 of the cleaning wheel according to the friction arc length K and the number of the cleaning teeth N; S5, calculating the circumference diameter φ2 of the cleaning teeth according to the friction circle diameter φ1 of the cleaning wheel, the distance L between the friction circle of the seed plate and the circle where the suction holes are located and the die drawing angle B of the cleaning wheel; S6, determining the angle A between the cleaning wheel and the seed plate; S7, calculating the angle C between the axis of the cleaning wheel and the seed plate according to the angle A between the cleaning wheel and the seed plate and the die drawing angle B of the cleaning wheel; S8, calculating the angle D between the cleaning teeth and the axis of the cleaning wheel according to the angle C between the axis of the cleaning wheel and the seed plate; S9, determining the structure size and the height h of the cleaning teeth according to the structure of the suction holes of the seed plate and the diameter, and completing the design.

[0037] The beneficial effects of the technical scheme of the present application are: the rotation of the cleaning wheel is driven by the friction between the edge of the cleaning wheel and the seed plate, the wear of the cleaning teeth is avoided, the service life and reliability of the cleaning teeth are improved, and the maintenance cost of the seed meter is reduced.

[0038] Further, in step S1, the distance L between the friction circle of the seed plate and the circle where the suction holes are located ranges from 5 to 15 mm, and step S1 comprises: determining the radius R of the friction circle of the seed plate according to the parameters of the suction holes of the seed plate.

[0039] The beneficial effects of the above further technical scheme are: in order to reduce the wind resistance, the diameter of the suction holes on the back of the seed plate is generally large, and in order to ensure that the seed plate provides sufficient friction force to the cleaning wheel, the friction circle of the seed plate should not overlap the suction holes.

[0040] Further, in step S3, the die drawing angle B of the cleaning wheel ranges from 0 to 6°, and the product of the friction arc length K and the number of the cleaning teeth N is the circumference of the friction circle of the cleaning wheel.

[0041] The beneficial effects of the above further technical scheme are: theoretically, the friction circle of the cleaning wheel rolls purely relative to the friction circle of the seed plate, so the product of the friction arc length K and the number of the cleaning teeth N is the circumference of the friction circle of the cleaning wheel. The die drawing angle B of the cleaning wheel ranges from 0 to 6°, which is convenient for machining.

[0042] Further, in step S4, the friction circle diameter φ1 of the cleaning wheel is calculated by the following formula: φ1=N×K / π, wherein φ1 is the friction circle diameter of the cleaning wheel, N is the number of the cleaning teeth, and K is the friction arc length.

[0043] The beneficial effects of the above further technical scheme are: the friction circle diameter of the cleaning wheel is accurately calculated by the formula, and the accuracy is improved.

[0044] Further, in step S5, the diameter of the circle where the unblocking tooth is located is calculated by the following formula: φ2=φ1+2LarctanB, wherein φ2 is the diameter of the circle where the unblocking tooth is located, φ1 is the diameter of the friction circle of the unblocking wheel, L is the distance between the friction circle of the seed plate and the circle where the suction hole is located, and B is the draft angle of the unblocking wheel.

[0045] The beneficial effect of the above further technical solution is that the diameter of the circle where the unblocking tooth is located is accurately calculated by the formula, thereby improving accuracy.

[0046] Further, in step S6, the included angle A between the unblocking wheel and the seed plate is in the range of 3-10°.

[0047] The beneficial effect of the above further technical solution is that the included angle A between the unblocking wheel and the seed plate is determined, and in order to ensure friction, the included angle A is generally 3-10°. The included angle A ensures that the unblocking wheel is in contact with the seed plate at the friction line, and the rest of the unblocking wheel is not in contact with the seed plate, so as to prevent deflection force caused by multiple parts of the unblocking wheel being in contact with the seed plate.

[0048] Further, in step S7, the included angle C between the axis of the unblocking wheel and the seed plate is calculated by the following formula: C=A+B, wherein C is the included angle between the axis of the unblocking wheel and the seed plate, A is the included angle between the unblocking wheel and the seed plate, and B is the draft angle of the unblocking wheel.

[0049] The beneficial effect of the above further technical solution is that the included angle between the axis of the unblocking wheel and the seed plate is accurately calculated by the formula, thereby improving accuracy.

[0050] Further, in step S8, the included angle D between the unblocking tooth and the axis of the unblocking wheel is calculated by the following formula: D=C+90°, wherein D is the included angle between the unblocking tooth and the axis of the unblocking wheel, and C is the included angle between the axis of the unblocking wheel and the seed plate.

[0051] The beneficial effect of the above further technical solution is that the included angle between the unblocking tooth and the axis of the unblocking wheel is accurately calculated by the formula, thereby improving accuracy.

[0052] Further, in step S9, according to the structure, diameter of the suction hole and the thickness H of the seed plate, the height h of the unblocking tooth is calculated by the following formula: h=(0.6-1.2)H, wherein H is the thickness of the seed plate, and h is the height of the unblocking tooth.

[0053] The beneficial effect of the above further technical solution is that the height of the unblocking tooth is accurately calculated by the formula, thereby improving accuracy.

[0054] As shown in FIG. 1, the design method (edge friction driving type unblocking wheel design method) provided by the embodiment of the present application comprises the following steps: Figures 1 to 8

[0055] ​S01, according to the suction hole 1.1 parameters of the seed plate, the friction circle of the seed plate and the suction hole spacing (the friction circle of the seed plate and the suction hole spacing L, generally 5-15 mm), the friction circle radius R of the seed plate;

[0056] In order to reduce the wind resistance, the diameter of the suction hole on the back of the seed plate is generally large, in order to ensure that the seed plate provides sufficient friction force to the cleaning wheel, the friction circle 1.2 of the seed plate should be avoided to overlap with the suction hole 1.1;

[0057] S02, calculate the friction arc length K corresponding to the angle of adjacent suction holes 1.1;

[0058] S03, according to the installation space of the cleaning wheel and the friction arc length K, determine the number of gear teeth (the number of cleaning teeth N) and the draft angle B of the cleaning wheel (the draft angle is 0-6°);

[0059] Theoretically, the friction circle 3.1 of the cleaning wheel rolls relative to the friction circle 1.2 of the seed plate, so the product of the friction arc length K and the number of cleaning teeth N is the circumference of the friction circle 3.1 of the cleaning wheel;

[0060] S04, calculate the diameter φ1 of the friction circle 3.1 of the cleaning wheel N×K / π, and the diameter φ2 of the circumference where the cleaning tooth 3.2 is located φ1+2LarctanB;

[0061] S05, determine the angle A between the cleaning wheel and the seed plate, generally 3-10° to ensure friction;

[0062] The angle (the angle A between the cleaning wheel and the seed plate) ensures that the cleaning wheel contacts the seed plate at the friction line, and the rest does not contact the seed plate, so as to prevent the deflection force caused by multiple contacts;

[0063] S06, calculate the angle C between the axis of the cleaning wheel and the seed plate C=A+B, and then get the angle D between the cleaning tooth and the axis of the cleaning wheel D=C+90°;

[0064] S07, according to the structure and diameter of the suction hole of the seed plate, determine the structure size (the thickness H of the seed plate) and the tooth height (the height h of the cleaning tooth) of the cleaning tooth h=(0.6-1.2)H, the tooth type of the cleaning tooth should be determined according to the specific suction hole structure; the key structure parameters of the cleaning wheel have been determined, the design is completed, and the overall structure is optimized, such as adding a certain fillet to the friction circle of the cleaning wheel to increase the friction force.

[0065] For example Figure 2As shown, the edge friction drive type blockage cleaning wheel design method (edge friction drive type blockage cleaning wheel design method) is as follows: S01, determining the seed plate friction circle and the suction hole spacing L (5-15 mm) and the seed plate friction circle radius R according to the seed plate suction hole parameters; S02, calculating the friction arc length K corresponding to the adjacent suction hole included angle; S03, determining the gear number N and the blockage cleaning wheel draft angle B (the draft angle is 0-6°) according to the blockage cleaning wheel installation space and the arc length K (friction arc length K);

[0066] S04, calculating the blockage cleaning wheel friction circle diameter φ1=N×K / π, and the blockage tooth located circle diameter φ2=φ1+2LarctanB; S05, determining the blockage cleaning wheel and the seed plate included angle A, generally 3-10° to ensure the friction force; S06, determining the blockage cleaning wheel axis and the seed plate included angle C=A+B, and then obtaining the blockage tooth and the axis included angle D; S07, determining the blockage tooth structure size according to the seed plate suction hole structure and diameter, completing the blockage cleaning wheel and support design, and optimizing.

[0067] As shown in the formula, Figures 3 to 8 In addition, the present application provides an edge friction drive type blockage cleaning device, which comprises a blockage cleaning wheel 3, a seed plate 1, a blockage cleaning wheel support 2 and a spring 4 designed by the edge friction drive type blockage cleaning wheel design method of any one of the above, one end of the blockage cleaning wheel support 2 is hinged to the seed plate bottom shell, the blockage cleaning wheel 3 is rotatably installed at the other end of the blockage cleaning wheel support 2, the two ends of the spring 4 are connected with the blockage cleaning wheel support 2 and the seed plate bottom shell respectively, the seed plate 1 is provided with a seed plate friction circle 1.2 and a plurality of suction holes 1.1, the blockage cleaning wheel 3 is provided with a blockage cleaning wheel friction circle 3.1 and a plurality of blockage teeth 3.2, the blockage teeth 3.2 are inserted into the suction holes 1.1, and the blockage cleaning wheel friction circle 3.1 abuts against the seed plate friction circle 1.2.

[0068] The beneficial effects of the technical scheme of the present application are as follows: after the seed plate is installed, the spring is compressed to generate a pre-tightening force, which can ensure that the blockage teeth generate an outward ejection force, and at the same time ensure that the seed plate friction circle and the blockage cleaning wheel friction circle are in close contact; when the seed plate rotates around its axis, the seed plate friction circle applies a friction force through the blockage cleaning wheel friction circle to drive the blockage cleaning wheel to rotate, and then the blockage teeth enter the suction holes of the seed plate in turn; when the suction holes are blocked, the blockage teeth eject the blockage, and the hole cleaning is completed. The edge of the blockage cleaning wheel and the seed plate are driven to rotate by friction, which avoids the wear of the blockage teeth and the suction holes, improves the service life and reliability of the blockage teeth, and reduces the maintenance cost of the seed plate. The design process of the edge friction drive type blockage cleaning wheel is standardized, the development cycle is shortened, and theoretical support is provided for the design of the blockage cleaning wheel.

[0069] The clogging wheel working system (edge friction driving type clogging device) is mainly composed of a seed plate 1, a clogging wheel support 2, a clogging wheel 3 and a spring 4. The clogging wheel support 2 is provided with a spring fixing seat 2.1, a support mounting shaft 2.2 and a wheel mounting shaft 2.3. The support mounting shaft 2.2 is hingedly mounted to the seed plate bottom shell. One end of the spring 4 is fixedly mounted at the spring fixing seat 2.1, and the other end is fixed to the seed plate bottom shell. The clogging wheel 3 is sleeved on the wheel mounting shaft 2.3 and can freely rotate therearound. A plurality of clogging teeth 3.2 are uniformly arranged on the outer circumference of the clogging wheel 3, and the clogging teeth 3.2 are inserted into the suction holes 1.1.

[0070] The seed plate 1 is provided with a seed plate friction arc 1.3, and the arc length of the seed plate friction arc 1.3 is the friction arc length K.

[0071] Working principle:

[0072] After the seed plate 1 is installed, the spring 4 is compressed to generate a pre-tightening force, so as to ensure that the clogging teeth 3.2 generate an outward ejection force, and at the same time, ensure that the seed plate friction circle 1.2 and the clogging wheel friction circle 3.1 are in close contact. When the seed plate rotates around its axis, the seed plate friction circle 1.2 applies a friction force through the clogging wheel friction circle 3.1 to drive the clogging wheel 3 to rotate, and then the clogging teeth 3.1 enter the suction holes 1.1 of the seed plate 1 in sequence. When the suction holes 1.1 are blocked, the clogging teeth 3.1 eject the blockage to complete the hole cleaning. In order to ensure sufficient friction force, the clogging wheel 3 should be made of a material with a high friction coefficient, and at the same time, a certain draft angle should be designed for easy processing.

[0073] The edge friction driving type clogging wheel does not rely on the meshing of the clogging teeth and the suction holes for driving, and the clogging teeth are almost not worn, so that the service life and reliability of the clogging wheel are improved, and the maintenance cost of the seed plate is reduced.

[0074] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present application, but not to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacement for part or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A method of designing an edge friction drive type cleanout wheel, characterized by, The method comprises the following steps: S1, determining the distance L between the friction circle of the seed plate and the circle where the suction holes are located according to the parameters of the suction holes of the seed plate; S2, calculating the length K of the friction arc corresponding to the included angle of adjacent suction holes; S3, determining the number N of the unblocking teeth and the draft angle B of the unblocking wheel according to the installation space of the unblocking wheel and the length K of the friction arc; S4, calculating the diameter φ1 of the friction circle of the unblocking wheel according to the length K of the friction arc and the number N of the unblocking teeth; S5, calculating the diameter φ2 of the circle where the unblocking teeth are located according to the diameter φ1 of the friction circle of the unblocking wheel, the distance L between the friction circle of the seed plate and the circle where the suction holes are located, and the draft angle B of the unblocking wheel; S6, determining the included angle A between the unblocking wheel and the seed plate; S7, calculating the included angle C between the axis of the unblocking wheel and the seed plate according to the included angle A between the unblocking wheel and the seed plate and the draft angle B of the unblocking wheel; S8, calculating the included angle D between the unblocking teeth and the axis of the unblocking wheel according to the included angle C between the axis of the unblocking wheel and the seed plate; S9, determining the structure size and the height h of the unblocking teeth according to the structure and diameter of the suction holes and the thickness H of the seed plate, and completing the design.

2. The method of designing a wheel for clearing blockages by edge friction drive as claimed in claim 1 wherein, In step S1, the distance L between the friction circle of the seed plate and the circle where the suction holes are located ranges from 5 mm to 15 mm. In step S1, the radius R of the friction circle of the seed plate is determined according to the parameters of the suction holes of the seed plate.

3. The method of designing a wheel for clearing blockages by edge friction drive as claimed in claim 1 wherein, In step S3, the draft angle B of the unblocking wheel ranges from 0° to 6°. The product of the length K of the friction arc and the number N of the unblocking teeth is the circumference of the friction circle of the unblocking wheel.

4. The method of designing a wheel for clearing blockages by edge friction drive as claimed in claim 1 wherein, In step S4, the diameter φ1 of the friction circle of the unblocking wheel is calculated by the following formula: φ1=N×K / π, wherein φ1 is the diameter of the friction circle of the unblocking wheel, N is the number of the unblocking teeth, and K is the length of the friction arc.

5. The method of designing a wheel for clearing blockages by edge friction drive as claimed in claim 1 wherein, In step S5, the diameter φ2 of the circle where the unblocking teeth are located is calculated by the following formula: φ2=φ1+2LarctanB, wherein φ2 is the diameter of the circle where the unblocking teeth are located, φ1 is the diameter of the friction circle of the unblocking wheel, L is the distance between the friction circle of the seed plate and the circle where the suction holes are located, and B is the draft angle of the unblocking wheel.

6. The method of designing a cleanout wheel with edge friction drive as claimed in claim 1 wherein, In step S6, the included angle A between the unblocking wheel and the seed plate ranges from 3° to 10°.

7. The method of designing a cleanout wheel with edge friction drive as claimed in claim 1 wherein, In step S7, the included angle C between the axis of the unblocking wheel and the seed plate is calculated by the following formula: C=A+B, wherein C is the included angle between the axis of the unblocking wheel and the seed plate, A is the included angle between the unblocking wheel and the seed plate, and B is the draft angle of the unblocking wheel.

8. The method of designing a wheel for clearing blockages by edge friction drive as claimed in claim 1 wherein, In step S8, the included angle D between the unblocking teeth and the axis of the unblocking wheel is calculated by the following formula: D=C+90°, wherein D is the included angle between the unblocking teeth and the axis of the unblocking wheel, and C is the included angle between the axis of the unblocking wheel and the seed plate.

9. The method of designing a wheel for clearing blockages by edge friction drive as claimed in claim 1 wherein, In step S9, the height h of the unblocking teeth is calculated by the following formula according to the structure and diameter of the suction holes and the thickness H of the seed plate: h=(0.6-1.2)H, wherein H is the thickness of the seed plate, and h is the height of the unblocking teeth.

10. A pigging device of the edge friction drive type, characterized in that The method comprises the following steps: The clog-removing wheel, seed disc, clog-removing wheel support and spring designed by the design method are characterized in that one end of the clog-removing wheel support is hingedly connected to a bottom shell of a seed metering device, the clog-removing wheel is rotatably installed at the other end of the clog-removing wheel support, two ends of the spring are respectively connected to the clog-removing wheel support and the bottom shell of the seed metering device, the seed disc is provided with a seed disc friction circle and a plurality of suction holes, the clog-removing wheel is provided with a clog-removing wheel friction circle and a plurality of clog-removing teeth, the clog-removing teeth are inserted into the suction holes, and the clog-removing wheel friction circle is in abutment with the seed disc friction circle.

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