Curve groove wheel type longitudinal accurate conveying device for rice seedling trays and conveying method of curve groove wheel type longitudinal accurate conveying device

Abstract

The invention discloses a curved groove wheel type longitudinal accurate conveying device for rice seedling trays and a conveying method of the curved groove wheel type longitudinal accurate conveying device. A roller is hinged to a beating rod, two cams are fixed to a rotating shaft, one end of a rocker is fixed to the rotating shaft, the middle of the rocker is fixed to a tension spring, the two ends of a connecting rod are hinged to the other end of the rocker and one end of a swing rod, and the other end of the swing rod is supported on a hollow shaft integrally formed on a driving gear through a one-way bearing. A plurality of driven gears are hinged to the gear frame, the driven gears are meshed with the driving gear, two symmetrically-arranged round pins are fixed to the driven gears, the balls and the springs are all arranged in a cylinder integrally formed on the brake hollow disc, and parts of the balls are exposed out of the cylinder; the ball is pressed by the spring; the part, exposed out of the cylinder, of the ball and the annular groove of the driving gear form a rolling friction pair, and the rolling friction pair is initially embedded into a groove formed in the annular groove. Longitudinal conveying work of seedling trays is achieved, the accuracy is high, and then the accuracy of transplanting work can be guaranteed.

Description

Technical Field

[0001] The invention belongs to the technical field of agricultural machinery, and in particular relates to a curved groove wheel type rice seedling tray longitudinal precision conveying device and a conveying method thereof. Background Art

[0002] The intermittent and fixed-distance longitudinal transportation of rice seedling trays is a prerequisite for the rice seedling transplanter to achieve precise transplanting. The existing longitudinal transportation mechanism of rice seedling trays is mainly ratchet type. However, the existing ratchet type longitudinal transportation mechanism of rice seedling trays has the problems of large rigid impact and unsatisfactory self-locking effect when working, which affects the accuracy of the longitudinal transportation of the seedling trays, and thus affects the accuracy of the transplanting work. Summary of the invention

[0003] The purpose of the present invention is to overcome the deficiencies of the prior art and to provide a curved groove wheel type rice seedling tray longitudinal precision conveying device and a conveying method thereof.

[0004] To achieve the above object, the present invention adopts the following technical solutions:

[0005] The invention discloses a curved groove wheel type rice seedling tray longitudinal precision conveying device, comprising a rotating shaft, a beating rod, a roller, a cam, a one-way bearing, a rocker, a tension spring, a connecting rod, a swing rod, a driving gear, a gear rack, a curved groove wheel mechanism and a braking mechanism.

[0006] The roller is hinged on the hitting rod, and two cams arranged at intervals are fixed on the horizontally arranged rotating shaft; one end of the rocker is fixed to the rotating shaft, the two ends of the connecting rod are hinged to the other end of the rocker and one end of the swing rod, and one end of the tension spring is fixed to the middle part of the rocker; the other end of the swing rod is supported on a hollow shaft integrally formed and coaxially arranged on the driving gear through a one-way bearing; an annular groove is provided on the driving gear, and a plurality of grooves uniformly distributed along the circumference are provided on the bottom surface of the annular groove; the curved groove wheel mechanism includes a curved groove wheel, a driven gear and a round pin, and a plurality of driven gears uniformly distributed along the circumference of the driving gear are all hinged to the gear frame and meshed with the driving gear, and each driven gear is fixed with a central pin about the driven gear. The curved groove wheel is coaxially arranged with the driving gear, and a plurality of wheel grooves are evenly distributed along the circumferential direction; the braking mechanism comprises a brake hollow disc, balls, springs and a brake fixed shell, the brake hollow disc is fixed on the brake fixed shell, the balls and springs are placed in a cylindrical cylinder integrally formed on the brake hollow disc, and a part of the balls is exposed outside the cylindrical cylinder; the balls are pressed by the springs; the part of the balls exposed outside the cylindrical cylinder and the annular groove of the driving gear form a rolling friction pair; in the initial state, the part of the balls exposed outside the cylindrical cylinder is embedded in one of the grooves, a round pin on each driven gear is embedded in a wheel groove of the curved groove wheel, and the round pins in each wheel groove are evenly distributed along the circumferential direction.

[0007] Preferably, the rocker arm is fixed to the outer ring of the one-way bearing, and the inner ring of the one-way bearing is fixed to the hollow shaft.

[0008] Preferably, an end of the cylindrical tube away from the ball is provided with an internal thread and is threadedly connected to the bolt, and two ends of the spring are in contact with the ball and the bolt respectively.

[0009] Preferably, the theoretical contour line of the curved groove wheel is composed of an arc part and a straight line part. The theoretical contour line design process of the curved groove wheel is as follows: assuming that the rotation center of one of the driven gears is point A, the rotation center of the curved groove wheel is point B, the initial positions of the centers of the two round pins on the driven gear are points C1 and D1 respectively, and when the driven gear drives the round pins to rotate, the trajectory circle of the centers of the round pins intersects with the line segment AB at point P1, assuming that when the driven gear drives the two round pins to rotate from the initial position by an angle of θ, the two round pins rotate from points C1 and D1 to points C2 and D2 respectively, the curved groove wheel stops, and when the driven gear drives the round pins to continue to rotate by an angle of Φ, the two round pins rotate from points C2 and D2 to points D1 and C1 respectively, and the curved groove The wheel rotates; during the movement of the curved groove wheel, the center of the round pin always moves along the theoretical contour line. When the curved groove wheel stops, the arc D1D2 with point A as the rotation center is the curved part of the theoretical contour line of the curved groove wheel; at point D2, the arc part and the straight part of the theoretical contour line of the curved groove wheel intersect, and a tangent to the arc D1D2 is made at point D2. When the center of the round pin moves from point D2 to point P2, the end point of the tangent line, along the tangent line relative to the curved groove wheel, the position of point P2 on the curved groove wheel reaches the position of point P1. A circle is made with point B as the center and BP1 as the radius. The intersection of the circle and the tangent line is point P2, and the straight line D2P2 is the straight part of the theoretical contour line of the curved groove wheel, thereby obtaining the theoretical contour line of the curved groove wheel.

[0010] More preferably, the rotation angle of the driven gear during the process from the round pin entering the wheel groove to exiting the wheel groove is 2α0, and the corresponding rotation angle of the curved groove wheel is Since the arc part of the theoretical contour line is tangent to the trajectory circle of the center of the round pin when the center of the round pin is at the exit point of the wheel groove, ∠AC1B=90°, then 2α0, There is the following relationship with the number of grooves Z of the curved groove wheel:

[0011]

[0012]

[0013] Assume that when the center of the round pin moves from the starting point to the end point of the straight line part of the theoretical contour line, the driven gear rotates through an angle of γ. At this time, the cylindrical surface of the round pin moves to the bottom of the wheel groove, that is, the center of the round pin moves from point D2 to point P1, and at the same time, the curved groove wheel rotates through ∠P1BP2. If the driven gear rotates again through an angle of γ, the center of the round pin moves from the end point of the straight line part of the theoretical contour line to the starting point, that is, the center of the round pin exits the straight line part and begins to enter the curved part, and let:

[0014]

[0015] Assume that the time for the driven gear to rotate one circle is T, and the time for the indexing motion of the curved groove wheel is t f The rest time is t d , then the motion coefficient τ and static coefficient g of the curved groove wheel mechanism are

[0016]

[0017]

[0018] The dynamic-stop ratio k of the curved groove wheel mechanism is the rotation time t of the curved groove wheel. f With rest time t d The ratio of

[0019]

[0020] More preferably, the relationship between the number of grooves of the curved groove wheel and the rotation radius of the seedling tray is:

[0021]

[0022] In the formula, l is the distance the seedling tray moves longitudinally each time, and r is the rotation radius of the seedling tray.

[0023] More preferably, the driven gear rotation angle α and the curved groove wheel rotation angle in a single motion cycle of the curved groove wheel are The analysis process of the relationship between them is:

[0024] When the round pin leaves the curved groove wheel, α=α0. During the rotation of the curved groove wheel, α∈[-γ,π / 2-π / Z]. Based on the segmentation of the round pin entering and leaving the straight part, the movement stage of the curved groove wheel is divided into three sections:

[0025] (1) The center of the circular pin moves from point D2 to point P1, at which point α∈[-γ,0];

[0026] (2) The center of the round pin moves from point P1 to the straight line part leaving the curved groove wheel, at this time α∈(0,γ);

[0027] (3) The center of the round pin moves from the point where it enters the curve to the point where it leaves the curve groove wheel, at which point α∈[γ,π / 2-π / Z];

[0028] Suppose the initial position of the theoretical contour line is expressed as D1D2P2. When the center of the round pin is at point D2, the curved groove wheel is at the starting position of the three-segment motion. Suppose the rotation center of the driven gear is point O1, and the rotation center of the curved groove wheel is point O2. A coordinate system is established with point O2 as the origin, the straight line O2O1 as the X-axis, and the straight line perpendicular to the straight line O2O1 and parallel to the end face of the driven gear as the Y-axis. Suppose the distance from the center of the curved groove wheel to the center of the driven gear is L, the distance from the center of the driven gear to the center of the round pin is R, the position point of the center of the round pin in the curved groove wheel is P, the length of the line segment O2P is ρ, the angle between the straight line O2P and the X-axis is β1, and a circle is drawn with O2 as the center and ρ as the radius, intersecting the initial position of the theoretical contour line at point P0 (x0, y0). The angle between the straight line O2P0 and the X-axis is β2, then

[0029]

[0030]

[0031]

[0032] In addition, R and L and The relationship is:

[0033]

[0034] When point P0 is located on the straight line of the theoretical contour line, the coordinates of point P0 satisfy

[0035]

[0036] When point P0 is located on the arc part of the theoretical contour line, the coordinates of point P0 satisfy

[0037]

[0038] The three-stage motion process is analyzed. The rotation angle of the curved groove wheel in the first stage of motion is The rotation angle of the curved groove wheel during the second and third stages of motion is

[0039]

[0040] The conveying method of the curved groove wheel type rice seedling tray longitudinal precision conveying device of the present invention is as follows:

[0041] The end of the beating rod away from the roller is fixed to the double helical shaft in the rice seedling transplanter, so that the rotating shaft is parallel to the double helical shaft and forms a rotating pair with the rice seedling box frame in the rice seedling transplanter, and the end of the tension spring away from the rocker is fixed to the rice seedling box frame; the curved groove wheel is fixed to the dial shaft in the rice seedling transplanter, the hollow shaft of the driving gear is sleeved on the dial shaft, and forms a rotating pair with the dial shaft, and the brake fixing shell and the gear frame are fixed to the rice seedling box frame; wherein, the dial shaft in the rice seedling transplanter and the rice seedling box frame form a rotating pair;

[0042] When the rice seedling transplanter is transplanting, the driving part drives the double screw shaft to rotate, and the double screw shaft drives the seedling box frame to move back and forth horizontally, and drives the beating rod and roller to rotate; when a row of seedlings at the seedling taking position on the seedling tray is taken, the seedling box frame moves to the corresponding extreme position, and a corresponding cam moves with the seedling box frame to align with the roller, the roller contacts the cam, and pushes the rotating shaft to rotate forward through the cam, and the rotating shaft drives the swing arm to rotate forward through the rocker and the connecting rod, the tension spring is stretched, and the swing arm drives the outer ring of the one-way bearing to rotate forward, the inner ring and the outer ring of the one-way bearing are locked, and the swing arm drives the active gear to rotate forward through the one-way bearing, the ball disengages from the corresponding groove, and moves relatively along the annular groove, the spring is further compressed, and the active gear meshes with the driven gears, and then drives the round pins to reverse through the driven gears, and the round pins mesh with the wheel groove of the curved groove wheel, thereby driving the curved groove wheel The line groove wheel rotates forward, thereby driving the dial shaft to rotate, and the disk winding mechanism on the dial shaft drives the seedling tray to move longitudinally; as the double spiral shaft continues to rotate, when the roller disengages from the cam, the ball moves to the next groove, and the spring pushes the ball to embed into the next groove, the driving gear stops rotating, and each driven gear rotates half a circle, and the other round pin on each driven gear is embedded in the corresponding next wheel groove, the curved groove wheel stops rotating, and the next row of seedlings on the seedling tray moves longitudinally to the seedling retrieval position. At the same time, the tension spring pulls the rocker to reverse to its original position, and the rocker drives the cam to reverse to its original position through the rotating shaft, and drives the swing arm to reverse to its original position through the connecting rod, and when the swing arm drives the outer ring of the one-way bearing to reverse, the outer ring and the inner ring of the one-way bearing are not locked, then the swing arm does not drive the driving gear to rotate when it reverses, thereby completing a longitudinal conveying of the seedling tray, and then the double spiral shaft drives the seedling box frame to translate in the opposite direction.

[0043] The present invention has the following beneficial effects:

[0044] The present invention can realize the precise longitudinal conveying of the seedling tray; specifically, the present invention drives the roller to hit the cam through the hitting rod, so that the cam drives the swing arm to rotate forward through the rotating shaft, the rocking arm and the connecting rod, and the swing arm drives the active gear to rotate forward through the one-way bearing, and the active gear drives each driven gear to reverse, and the round pin of each driven gear drives the curved groove wheel to rotate forward, and the curved groove wheel drives the dial shaft to rotate, so that the winding disk mechanism on the dial shaft drives the seedling tray to move longitudinally, thereby realizing the longitudinal conveying of the seedling tray; compared with the ratchet mechanism, the curved groove wheel mechanism adopted by the present invention mainly has a flexible impact mode, which is In the linear groove wheel mechanism, the flexible impact is small, and two round pins are provided on the driven gear in the curved groove wheel mechanism, which can realize the positioning and self-locking of the curved groove wheel, and the positioning accuracy is higher, thereby improving the accuracy of the longitudinal transportation of the seedling tray; further, a braking mechanism is provided in the present invention, and a ball is embedded in a groove on the driving gear through a spring, so that the driving gear will not continue to rotate due to inertia when it is not rotating, ensuring that the vibration of the seedling box during non-longitudinal transportation will not affect the position of each gear, further ensuring the accuracy of the longitudinal transportation of the seedling tray. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Figure 1 This is a schematic diagram of the structure of the present invention installed on a rice seedling pot transplanter;

[0046] Figure 2 It is a structural diagram of the present invention;

[0047] Figure 3 It is a cross-sectional view of the driving gear and the brake mechanism after removing the brake fixing housing in the present invention;

[0048] Figure 4 It is a geometrical schematic diagram of the curved groove wheel mechanism in the present invention;

[0049] Figure 5 It is a schematic diagram of the longitudinal transportation of the seedling tray;

[0050] Figure 6 is the rotation angle α of the driven gear and the rotation angle of the curved groove wheel in the present invention Relationship analysis diagram;

[0051] Figure 7 Schematic diagram of the angular velocity and angular acceleration curves of the curved sheave in the present invention;

[0052] Figure 8 Schematic diagram of the angular velocity and angular acceleration curves of linear groove wheels of the same size. DETAILED DESCRIPTION

[0053] The present invention is further described below in conjunction with the accompanying drawings.

[0054] like Figure 1 , Figure 2 and Figure 3 As shown, a curved groove wheel type rice seedling tray longitudinal precision conveying device of the present invention includes a rotating shaft, a beating rod 1, a roller 2, a cam 3, a rocker 4, a tension spring 5, a connecting rod 6, a rocker 7, a driving gear 8, a one-way bearing 12, a gear rack, a curved groove wheel mechanism and a braking mechanism. The roller 2 is hinged on the rod 1, and two cams 3 arranged at intervals are fixed on the horizontally arranged rotating shaft; one end of the rocking arm 4 is fixed to the rotating shaft, and the two ends of the connecting rod 6 are hinged to the other end of the rocking arm 4 and one end of the rocking rod 7, and one end of the tension spring 5 is fixed to the middle part of the rocking arm 4; the other end of the rocking rod 7 is fixed to the outer ring of the one-way bearing 12, and the inner ring of the one-way bearing 12 is fixed to the hollow shaft integrally formed and coaxially arranged on the driving gear 8; an annular groove is provided on the driving gear 8, and a plurality of grooves uniformly distributed along the circumferential direction are provided on the bottom surface of the annular groove; the curved groove wheel mechanism includes a curved groove wheel 9, a driven gear 10 and a round pin 11, and a plurality of driven gears 10 uniformly distributed along the circumference of the driving gear 8 are all hinged to the gear frame, The two driven gears 10 are meshed with the driving gear 8, and two round pins 11 are fixed on each driven gear 10, which are arranged symmetrically about the center of the driven gear 10. The curved groove wheel 9 is coaxially arranged with the driving gear 8, and the curved groove wheel 9 is provided with a plurality of wheel grooves evenly distributed along the circumferential direction. The brake mechanism includes a brake hollow disc 13, a ball 14, a spring 15 and a brake fixed housing 16. The brake hollow disc 13 is fixed on the brake fixed housing 16. The ball 14 and the spring 15 are both placed in a cylindrical cylinder integrally formed on the brake hollow disc 13, and the ball 14 is partially exposed outside the cylindrical cylinder. The ball 14 is pressed by the spring 15. The part of the ball 14 exposed outside the cylindrical cylinder forms a rolling friction pair with the annular groove of the driving gear 8. In the initial state, the part of the ball 14 exposed outside the cylindrical cylinder is embedded in one of the grooves, the driving gear 8 is locked, and a round pin 11 on each driven gear 10 is embedded in a wheel groove of the curved groove wheel 9, and is located at the same position in each wheel groove (the round pins in each wheel groove are evenly distributed along the circumferential direction).

[0055] As a preferred embodiment, an internal thread is provided at one end of the cylindrical tube away from the ball 14 and is threadedly connected to the bolt 17. Both ends of the spring 15 are in contact with the ball 14 and the bolt 17 respectively. The preload force of the spring 15 can be adjusted by controlling the depth of the bolt 17 screwed into the cylindrical tube.

[0056] The conveying method of the curved groove wheel type rice seedling tray longitudinal precision conveying device of the present invention is as follows:

[0057] like Figure 1As shown, the ratchet-type mechanism for realizing the longitudinal conveying function of the seedling tray in the rice seedling transplanter is replaced by the present invention, and the end of the beating rod 1 away from the roller 2 is fixed to the double helical shaft 20 in the rice seedling transplanter, so that the rotating shaft is parallel to the double helical shaft 20 and forms a rotation pair with the seedling box frame in the rice seedling transplanter, and the end of the tension spring 5 away from the rocker 4 is fixed to the seedling box frame; the curved groove wheel 9 is fixed to the dial shaft 21 in the rice seedling transplanter, and the hollow shaft of the driving gear 8 is sleeved on the dial shaft and forms a rotation pair with the dial shaft, and the brake fixing housing 16 and the gear frame are fixed to the seedling box frame. Among them, the dial shaft in the rice seedling transplanter forms a rotation pair with the seedling box frame.

[0058] When the rice seedling transplanter is transplanting rice seedlings, the driving member drives the double screw shaft 20 to rotate, and the double screw shaft 20 drives the seedling box frame to move back and forth horizontally, and drives the beating rod 1 and the roller 2 to rotate; when a row of seedlings at the seedling taking position on the seedling tray 19 is taken out, the seedling box frame moves to the corresponding extreme position, and a corresponding cam 3 moves with the seedling box frame to align with the roller 2, the roller 2 contacts the cam 3, and the cam 3 drives the rotating shaft to rotate forward, and the rotating shaft drives the rocking arm 4 and the connecting rod 6 to rotate. When the rod 7 rotates forward, the tension spring 5 is stretched, and the swing rod 7 drives the outer ring of the one-way bearing 12 to rotate forward, the inner ring and the outer ring of the one-way bearing 12 are locked, and the swing rod 7 drives the driving gear 8 to rotate forward through the one-way bearing 12, and the ball 14 is separated from the corresponding groove and moves relatively along the annular groove, and the spring 15 is further compressed, and the driving gear 8 is meshed with each driven gear 10, and then the round pins 11 are driven to reverse through each driven gear 10, and each round pin 11 is meshed with the wheel groove of the curved groove wheel 9, thereby driving the curved groove wheel 9 to rotate forward. The line groove wheel 9 rotates forward, thereby driving the dial shaft to rotate, and the winding disc mechanism 18 on the dial shaft drives the seedling tray 19 to move longitudinally; as the double spiral shaft 20 continues to rotate, when the roller 2 is out of contact with the cam 3, the ball 14 moves to the next groove, and the spring 15 pushes the ball 14 to embed into the next groove, the driving gear 8 stops rotating, each driven gear 10 rotates half a circle, and another round pin 11 on each driven gear 10 is embedded in the corresponding next wheel groove, the curved groove wheel 9 stops rotating, and the next row of seedlings in the seedling tray 19 moves longitudinally to the seedling taking position, and at the same time, the tension spring 5 pulls the rocker 4 to reverse to its original position, and the rocker 4 drives the cam 3 to reverse to its original position through the rotating shaft, and drives the swing rod 7 to reverse to its original position through the connecting rod 6, and when the swing rod 7 drives the outer ring of the one-way bearing 12 to reverse, the outer ring and the inner ring of the one-way bearing 12 are not locked, then the swing rod 7 does not drive the driving gear 8 to rotate when it reverses, thereby completing a longitudinal conveying work of the seedling tray, and then the double spiral shaft 20 drives the seedling box frame to translate in the opposite direction. Among them, the disk winding mechanism 18 includes a positioning frame 22 and a disk feeding wire 23. The positioning frame 22 is fixed on the dial shaft 21. Multiple disk feeding wires 23 are evenly distributed and fixed on the positioning disk 22 along the circumferential direction. Every time the driven gear 10 rotates half a circle, a disk feeding wire 23 drives the seedling disk 19 to move longitudinally by one row.

[0059] Among them, the theoretical contour line of the curved sheave wheel 9 is composed of an arc part and a straight line part, and the theoretical contour line design process of the curved sheave wheel 9 is:

[0060] like Figure 4 As shown, let the rotation center of one of the driven gears 10 be point A, the rotation center of the curved groove wheel 9 be point B, the initial positions of the centers of the two round pins 11 on the driven gear 10 are points C1 and D1 respectively, when the driven gear 10 drives the round pin 11 to rotate, the trajectory circle of the center of the round pin 11 intersects with the line segment AB at point P1, the curved groove wheel mechanism is an intermittent motion mechanism, let the driven gear 10 drive the two round pins 11 to rotate from the initial position by an angle θ, the two round pins 11 rotate from points C1 and D1 to points C2 and D2 respectively, the curved groove wheel 9 stops, when the driven gear 10 drives the round pins 11 to continue to rotate by an angle Φ, the two round pins 11 rotate from points C2 and D2 to points D1 and C1 respectively, and the curved groove wheel 9 rotates; in the process of the curved groove wheel movement, in order to avoid motion distortion, the center of the round pin should always move along the theoretical contour line, then when the curved groove wheel 9 stops, the arc D with point A as the rotation center 1D2 is the curve part of the theoretical contour line of the curved groove wheel 9; at point D2, the arc part and the straight part of the theoretical contour line of the curved groove wheel 9 intersect. In order to ensure that the speed curve of the curved groove wheel 9 is continuous and smooth at the intersection of the arc part and the straight part of the theoretical contour line during the movement, the arc part and the straight part are tangent, and a tangent of the arc D1D2 is made at point D2. When the center of the round pin moves from point D2 to the end point P2 of the tangent line relative to the curved groove wheel 9 along the tangent line, the position of point P2 on the curved groove wheel 9 reaches the position of point P1. Then, a circle is made with point B as the center and BP1 as the radius. The intersection of the circle and the tangent line is point P2. The straight line D2P2 is the straight part of the theoretical contour line of the curved groove wheel 9, and then the theoretical contour line of the curved groove wheel 9 is obtained. Since the driven gear 10 is provided with two symmetrically arranged round pins 11, the curved groove wheel 9 has two motion cycles and rotates through two wheel grooves for every rotation of the driven gear 10.

[0061] In addition, suppose that the rotation angle of the driven gear 10 during the process from the round pin entering (the symmetrical point position of point C1 about line segment AB is the entry point) to exiting (the position of point C1 is the exit point) the wheel groove is 2α0, and the corresponding rotation angle of the curved groove wheel 9 is Since the arc part of the theoretical contour line is tangent to the trajectory circle of the center of the round pin when the center of the round pin is at the exit point of the wheel groove, ∠AC1B=90°, then 2α0, There is the following relationship with the number of grooves Z of the curved groove wheel:

[0062]

[0063]

[0064] Assume that when the center of the round pin moves from the starting point to the end point of the straight line part of the theoretical contour line, the driven gear 10 rotates through an angle of γ. At this time, the cylindrical surface of the round pin moves to the bottom of the wheel groove, that is, the center of the round pin moves from point D2 to point P1, and at the same time, the curved groove wheel rotates through ∠P1BP2. If the driven gear rotates again through an angle of γ, the center of the round pin moves from the end point of the straight line part of the theoretical contour line to the starting point, that is, the center of the round pin exits the straight line part and begins to enter the curved part, and let:

[0065]

[0066] Assume that the time for the driven gear 10 to rotate one circle is T, and the time for the indexing motion of the curved groove wheel 9 is t f (The center of the round pin moves from point D2 to point C1), the rest time is t d , then the motion coefficient τ and the static coefficient g of the grooved wheel mechanism are

[0067]

[0068]

[0069] The dynamic-stop ratio k of the curved groove wheel mechanism is the rotation time t of the curved groove wheel. f With rest time t d The ratio of

[0070]

[0071] From the above formula, we can know that the motion law of the curved groove wheel mechanism is determined by the number of grooves of the curved groove wheel. As the number of grooves Z of the curved groove wheel increases, the dynamic-stop ratio k of the curved groove wheel mechanism decreases, and the motion time t of the curved groove wheel is f The working efficiency of the curved groove wheel mechanism is improved by reducing the center distance between the curved groove wheel and the driven gear. In addition, the center distance between the curved groove wheel and the driven gear only affects the overall size of the curved groove wheel, while the number of grooves of the curved groove wheel affects the shape of the theoretical contour line of the curved groove wheel and determines the turning radius of the seedling tray when it passes around the bottom of the seedling box. If the turning radius is too large, the seedling picking position point is too high, which affects the uprightness of the seedling planting. If the turning radius is too small, the seedling tray will produce too much deformation during the winding process. The greater the deformation, the greater the resistance generated by the seedling tray when transporting the seedling tray, and the greater the possibility of damage to the seedling tray. Therefore, the number of grooves of the curved groove wheel is a key indicator for designing the winding mechanism 18. Figure 5 As shown, assuming that the distance of each longitudinal movement of the seedling tray 19 is l, and the rotation radius of the seedling tray 19 is r, according to the working principle, the seedling tray 19 moves longitudinally by a distance l each time the curved groove wheel rotates through a wheel groove, and the relationship between the number of wheel grooves Z of the curved groove wheel and the rotation radius r of the seedling tray is:

[0072]

[0073] Further, according to the motion process of the curved groove wheel, the rotation angle α of the driven gear and the rotation angle of the curved groove wheel in a single motion cycle of the curved groove wheel are calculated. Analyze the relationship between them. When the round pin leaves the curved groove wheel, α=α0. During the rotation of the curved groove wheel, α∈[-γ,π / 2-π / Z]. Since the theoretical contour line of the curved groove wheel is asymmetric, the motion law is not symmetric during the motion process. Based on the segmentation of the round pin entering and leaving the straight part, the motion stage of the curved groove wheel is divided into 3 sections:

[0074] (1) The center of the round pin moves from point D2 to point P1 (that is, when the center of the round pin moves from point D2 to point P2 along the straight line relative to the curved groove wheel 9), at this time α∈[-γ,0];

[0075] (2) The center of the round pin moves from point P1 to the straight part leaving the curved groove wheel 9 (i.e., entering the curved part), at which time α∈(0,γ);

[0076] (3) The center of the round pin moves from the point where it enters the curve to the point where it leaves the curve groove wheel, and at this point α∈[γ,π / 2-π / Z].

[0077] During these three movements, α and The relationship between them is different. The three-stage motion process is analyzed. The initial position of the theoretical contour line is expressed as D1D2P2. When the center of the round pin is at point D2, the curved groove wheel is at the starting position of the three-stage motion. Figure 6 As shown, let O1 be the rotation center of the driven gear, O2 be the rotation center of the curved groove wheel, and establish a coordinate system with O2 as the origin, straight line O2O1 as the X-axis, and the straight line perpendicular to O2O1 and parallel to the end face of the driven gear as the Y-axis. Let L be the distance from the center of the curved groove wheel to the center of the driven gear, R be the distance from the center of the driven gear to the center of the round pin, P be the position of the center of the round pin in the curved groove wheel, ρ be the length of the line segment O2P, β1 be the angle between the straight line O2P and the X-axis, and draw a circle with O2 as the center and ρ as the radius, which intersects the theoretical contour line at the initial position at point P0 (x0, y0). β2 be the angle between the straight line O2P0 and the X-axis, then

[0078]

[0079] In addition, if Figure 4 As shown, R and L and The relationship is:

[0080]

[0081] When point P0 is located on the straight line of the theoretical contour line, the coordinates of point P0 satisfy (the difference between the x- and y-coordinates of point P0 and the x- and y-coordinates of point D2 in the triangle is expressed as follows: )

[0082]

[0083] When point P0 is located on the arc part of the theoretical contour line, the coordinates of point P0 satisfy

[0084]

[0085] The three-stage motion process is analyzed. The rotation angle of the curved groove wheel in the first stage of motion is The rotation angle of the curved groove wheel during the second and third stages of motion is Among them, at the beginning of the 3-stage motion, the center of the round pin is located at point D2 of the straight line part of the theoretical contour line. When the round pin rotates through the -γ angle, the cylindrical surface of the round pin is located at the bottom of the curved groove wheel groove, and the center of the round pin is located on the straight line O2O1, that is, point P is located on the straight line O2O1, and the corresponding point P0 is located as follows: Figure 4 Point P2 of the straight line part of the theoretical contour line shown in the figure, at this time α=0, substitute into equation (7) and equation (9), and obtain β1 and ρ, and then use equation (11) to obtain the horizontal coordinate x0 and vertical coordinate y0 of point P0, and then use equation (8) to obtain β2, and finally obtain Similarly, the rotation angle of the curved groove wheel at each position during the motion process can be obtained by analysis and calculation. and

[0086] From the above, we can know that the angle of the curved groove wheel There is a functional relationship between and the driven gear rotation angle α, let The first and second order derivatives of f(α) with respect to time t are obtained, and then the formulas for the angular velocity and angular acceleration of the curved groove wheel are obtained, which are

[0087]

[0088]

[0089] Wherein, ω1 is the angular velocity of the driven gear 10, and ω2 is the angular velocity of the curved groove wheel 9.

[0090] like Figure 7 As shown in the figure, the curves of ω2 and ε2 are drawn by Matlab software. Figure 7It can be seen that in the first segment of movement, after the round pin enters the curved groove wheel, the angular velocity of the curved groove wheel gradually increases, but the maximum value of the angular velocity of the curved groove wheel does not occur at the position of α=0°. When the round pin leaves the straight part of the contour line of the curved groove wheel, that is, when the second segment of movement is completed, the angular velocity of the curved groove wheel is the maximum value, the angular acceleration is 0, and the direction of the angular acceleration is ready to change direction. During the third segment of movement, the curved groove wheel begins to decelerate, and the angular velocity slowly decreases until the round pin completely exits the curved groove wheel. The angular acceleration of the round pin is not 0 when entering and exiting the curved groove wheel, indicating that this type of special-shaped groove wheel still has flexible impact. In order to prove that the flexible impact of the mechanism is smaller than that of the linear groove wheel with the same L and R dimensions, the motion of the linear groove wheel with the same L and R dimensions is analyzed.

[0091] During the motion of the linear groove wheel mechanism, the dial angle α2 and the linear groove wheel angle Always satisfy the following formula:

[0092]

[0093] Attention, corner is the angle of the current position of the curved sheave relative to the position of the straight line BP2, and the angle It is the rotation angle of the current position of the linear sheave relative to the position of the line connecting the linear sheave and the center of the dial. Although there is an angle difference with the reference straight line, the angle difference is a constant value and does not affect the rotation angle. or corner Comparison of angular velocity and angular acceleration after differentiation.

[0094] By taking the first and second order derivatives of the above formula with respect to time, we can obtain the angular velocity ω of the dial in the linear grooved wheel mechanism: 21 Angular velocity ω of the linear sheave 22 and angular acceleration ε 22 The relationship between

[0095]

[0096]

[0097] Plotted by Matlab software 22 and ε 22 The curve diagram of Figure 8 As shown in the figure, in a single motion process of the linear groove wheel mechanism with the same L and R dimensions, the dial angle α2∈[-3π / 7,3π / 7], the angular velocity change curve is symmetrical about α2=0°, and the angular velocity reaches the maximum value when α2=0°. Figure 7 and Figure 8It was found that: at the beginning of the movement, the angular acceleration mutation of the curved groove wheel is smaller than the angular acceleration mutation of the linear groove wheel, which proves that the curved groove wheel has a smaller flexible impact than the linear groove wheel with the same L and R dimensions, that is, the impact force of the dial on the curved groove wheel when it is just about to move is smaller than the impact force of the dial on the linear groove wheel when it is just about to move. In this way, the curved groove wheel mechanism in the present invention has less noise than the existing linear groove wheel mechanism.

[0098] The impact force of the linear groove wheel mechanism when it is about to move is obviously smaller than the impact force of the ratchet mechanism when it is about to move. In this way, the use of the present invention to replace the existing ratchet type mechanism for realizing the longitudinal conveying function of the seedling tray will inevitably avoid the problem of large rigid impact of the existing ratchet type mechanism for realizing the longitudinal conveying function of the seedling tray when working. Instead, it has a smaller flexible impact than the linear groove wheel mechanism, and can solve the problem of unsatisfactory self-locking effect of the ratchet mechanism (the ratchet mechanism relies on the flexible connection of the spring to realize movement), thereby greatly improving the accuracy of the longitudinal conveying of the seedling tray, and thus improving the accuracy of transplanting work.

Claims

1. A curved groove wheel type rice seedling tray longitudinal precision conveying device, comprising a beating rod, a roller, a cam and a one-way bearing, characterized in that: It also includes a rotating shaft, a rocking arm, a tension spring, a connecting rod, a rocking arm, a driving gear, a gear frame, a curved groove wheel mechanism and a braking mechanism; the roller is hinged on the hitting rod, and two cams arranged at intervals are fixed on the horizontally arranged rotating shaft; one end of the rocking arm is fixed to the rotating shaft, the two ends of the connecting rod are hinged to the other end of the rocking arm and one end of the rocking arm, and one end of the tension spring is fixed to the middle part of the rocking arm; the other end of the rocking arm is supported on a hollow shaft integrally formed and coaxially arranged on the driving gear through a one-way bearing; an annular groove is provided on the driving gear, and a plurality of grooves evenly distributed along the circumferential direction are provided on the bottom surface of the annular groove; the curved groove wheel mechanism includes a curved groove wheel, a driven gear and a round pin, along the driving gear A plurality of driven gears uniformly distributed in the circumferential direction of the gear are all hinged to the gear frame and meshed with the driving gear, and two round pins symmetrically arranged about the center of the driven gear are fixed on each driven gear; the curved groove wheel is coaxially arranged with the driving gear, and the curved groove wheel is provided with a plurality of wheel grooves uniformly distributed along the circumferential direction; the braking mechanism comprises a brake hollow disc, balls, springs and a brake fixed housing, the brake hollow disc is fixed on the brake fixed housing, the balls and springs are both placed in a cylindrical barrel integrally formed on the brake hollow disc, and a part of the balls is exposed outside the cylindrical barrel; the balls are pressed by the springs; the part of the balls exposed outside the cylindrical barrel forms a rolling friction pair with the annular groove of the driving gear; In the initial state, the portion of the ball protruding from the cylindrical tube is embedded in one of the grooves, and a round pin on each driven gear is embedded in a wheel groove of the curved groove wheel.

2. The device for longitudinal precise conveying of rice seedling trays with curved groove wheels according to claim 1, characterized in that: The swing rod is fixed to the outer ring of the one-way bearing, and the inner ring of the one-way bearing is fixed to the hollow shaft.

3. The device for longitudinal precise conveying of rice seedling trays with curved groove wheels according to claim 1, characterized in that: An end of the cylindrical tube away from the ball is provided with an internal thread and is connected with the bolt through a thread, and two ends of the spring are respectively in contact with the ball and the bolt.

4. The device for longitudinal precise conveying of rice seedling trays with curved groove wheels according to claim 1, characterized in that: The theoretical contour line of the curved groove wheel is composed of an arc part and a straight line part. The design process of the theoretical contour line of the curved groove wheel is as follows: Assume that the rotation center of one of the driven gears is point A, the rotation center of the curved groove wheel is point B, the initial positions of the centers of the two round pins on the driven gear are points C1 and D1 respectively, and when the driven gear drives the round pin to rotate, the trajectory circle of the round pin center intersects with line segment AB at point P1. Assume that when the driven gear drives the two round pins to rotate by angle θ from the initial position, the two round pins rotate from points C1 and D1 to points C2 and D2 respectively, and the curved groove wheel stops. When the driven gear drives the round pins to continue to rotate by angle Φ, the two round pins rotate from points C2 and D2 to points D1 and C1 respectively, and the curved groove wheel rotates; during the movement of the curved groove wheel, the center of the round pin always moves along the rational In terms of contour line movement, when the curved groove wheel stops, the arc D1D2 with point A as the rotation center is the curved part of the theoretical contour line of the curved groove wheel; at point D2, the arc part and the straight part of the theoretical contour line of the curved groove wheel intersect, and a tangent to the arc D1D2 is made at point D2. When the center of the round pin moves from point D2 to point P2, the end point of the tangent line, along the tangent line relative to the curved groove wheel, the position of point P2 on the curved groove wheel reaches point P1. A circle is made with point B as the center and BP1 as the radius. The intersection of the circle and the tangent line is point P2, and the straight line D2P2 is the straight part of the theoretical contour line of the curved groove wheel, thereby obtaining the theoretical contour line of the curved groove wheel.

5. The device for longitudinal precise conveying of rice seedling trays with curved groove wheels according to claim 4, characterized in that: Assume that the rotation angle of the driven gear from the round pin entering the wheel groove to exiting the wheel groove is 2α0, and the corresponding rotation angle of the curved groove wheel is Since the arc part of the theoretical contour line is tangent to the trajectory circle of the center of the round pin when the center of the round pin is at the exit point of the wheel groove, ∠AC1B=90°, then 2α0, There is the following relationship with the number of grooves Z of the curved groove wheel: Assume that when the center of the round pin moves from the starting point to the end point of the straight line part of the theoretical contour line, the driven gear rotates through an angle of γ. At this time, the cylindrical surface of the round pin moves to the bottom of the wheel groove, that is, the center of the round pin moves from point D2 to point P1, and at the same time, the curved groove wheel rotates through ∠P1BP2. If the driven gear rotates again through an angle of γ, the center of the round pin moves from the end point of the straight line part of the theoretical contour line to the starting point, that is, the center of the round pin exits the straight line part and begins to enter the curved part, and let: Assume that the time for the driven gear to rotate one circle is T, and the time for the indexing motion of the curved groove wheel is t f The rest time is t d , then the motion coefficient τ and static coefficient g of the curved groove wheel mechanism are The dynamic-stop ratio k of the curved groove wheel mechanism is the rotation time t of the curved groove wheel. f With rest time t d The ratio of 6. The device for longitudinal precise conveying of rice seedling trays with curved groove wheels according to claim 5, characterized in that: The relationship between the number of grooves of the curved groove wheel and the rotation radius of the seedling tray is: In the formula, l is the distance the seedling tray moves longitudinally each time, and r is the rotation radius of the seedling tray.

7. The device for longitudinal precise conveying of rice seedling trays with curved groove wheels according to claim 4, characterized in that: The driven gear rotation angle α and the curved groove wheel rotation angle in a single motion cycle of the curved groove wheel The analysis process of the relationship between them is: When the round pin leaves the curved groove wheel, α=α0. During the rotation of the curved groove wheel, α∈[-γ,π / 2-π / Z]. Based on the segmentation of the round pin entering and leaving the straight part, the movement stage of the curved groove wheel is divided into three sections: (1) The center of the circular pin moves from point D2 to point P1, at which point α∈[-γ,0]; (2) The center of the round pin moves from point P1 to the straight line part leaving the curved groove wheel, at this time α∈(0,γ); (3) The center of the round pin moves from the point where it enters the curve to the point where it leaves the curve groove wheel, at which point α∈[γ,π / 2-π / Z]; Suppose the initial position of the theoretical contour line is expressed as D1D2P2. When the center of the round pin is at point D2, the curved groove wheel is at the starting position of the three-segment motion. Suppose the rotation center of the driven gear is point O1, and the rotation center of the curved groove wheel is point O2. A coordinate system is established with point O2 as the origin, the straight line O2O1 as the X-axis, and the straight line perpendicular to the straight line O2O1 and parallel to the end face of the driven gear as the Y-axis. Suppose the distance from the center of the curved groove wheel to the center of the driven gear is L, the distance from the center of the driven gear to the center of the round pin is R, the position point of the center of the round pin in the curved groove wheel is P, the length of the line segment O2P is ρ, the angle between the straight line O2P and the X-axis is β1, and a circle is drawn with O2 as the center and ρ as the radius, intersecting the initial position of the theoretical contour line at point P0 (x0, y0). The angle between the straight line O2P0 and the X-axis is β2, then In addition, R and L and The relationship is: When point P0 is located on the straight line of the theoretical contour line, the coordinates of point P0 satisfy When point P0 is located on the arc part of the theoretical contour line, the coordinates of point P0 satisfy The three-stage motion process is analyzed. The rotation angle of the curved groove wheel in the first stage of motion is The rotation angle of the curved groove wheel during the second and third stages of motion is 8. A conveying method for a curved groove wheel type rice seedling tray longitudinal precision conveying device according to any one of claims 1 to 7, characterized in that: The details are as follows: The end of the beating rod away from the roller is fixed to the double helical shaft in the rice seedling transplanter, so that the rotating shaft is parallel to the double helical shaft and forms a rotating pair with the rice seedling box frame in the rice seedling transplanter, and the end of the tension spring away from the rocker is fixed to the rice seedling box frame; the curved groove wheel is fixed to the dial shaft in the rice seedling transplanter, the hollow shaft of the driving gear is sleeved on the dial shaft, and forms a rotating pair with the dial shaft, and the brake fixing shell and the gear frame are fixed to the rice seedling box frame; wherein, the dial shaft in the rice seedling transplanter and the rice seedling box frame form a rotating pair; When the rice seedling transplanter is transplanting, the driving part drives the double screw shaft to rotate, and the double screw shaft drives the seedling box frame to move back and forth horizontally, and drives the beating rod and roller to rotate; when a row of seedlings at the seedling taking position on the seedling tray is taken, the seedling box frame moves to the corresponding extreme position, and a corresponding cam moves with the seedling box frame to align with the roller, the roller contacts the cam, and pushes the rotating shaft to rotate forward through the cam, and the rotating shaft drives the swing arm to rotate forward through the rocker and the connecting rod, the tension spring is stretched, and the swing arm drives the outer ring of the one-way bearing to rotate forward, the inner ring and the outer ring of the one-way bearing are locked, and the swing arm drives the active gear to rotate forward through the one-way bearing, the ball disengages from the corresponding groove, and moves relatively along the annular groove, the spring is further compressed, and the active gear meshes with the driven gears, and then drives the round pins to reverse through the driven gears, and the round pins mesh with the wheel groove of the curved groove wheel, thereby driving the curved groove wheel The line groove wheel rotates forward, thereby driving the dial shaft to rotate, and the disk winding mechanism on the dial shaft drives the seedling tray to move longitudinally; as the double spiral shaft continues to rotate, when the roller disengages from the cam, the ball moves to the next groove, and the spring pushes the ball to embed into the next groove, the driving gear stops rotating, and each driven gear rotates half a circle, and the other round pin on each driven gear is embedded in the corresponding next wheel groove, the curved groove wheel stops rotating, and the next row of seedlings on the seedling tray moves longitudinally to the seedling retrieval position. At the same time, the tension spring pulls the rocker to reverse to its original position, and the rocker drives the cam to reverse to its original position through the rotating shaft, and drives the swing arm to reverse to its original position through the connecting rod, and when the swing arm drives the outer ring of the one-way bearing to reverse, the outer ring and the inner ring of the one-way bearing are not locked, then the swing arm does not drive the driving gear to rotate when it reverses, thereby completing a longitudinal conveying of the seedling tray, and then the double spiral shaft drives the seedling box frame to translate in the opposite direction.

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