Header pressure profiling control system and agricultural machine

Abstract

The present application relates to a kind of header pressure profiling control systems and agricultural machinery, and the profiling control of header pressure profiling control system is used to the front side of bridge assembly, one side middle part of header is rotatably connected in the front side of bridge assembly by pivot;Including header lift cylinder and header tilt cylinder;Rodless chamber of header lift cylinder and rodless chamber of header tilt cylinder are connected hydraulic source;Rod chamber of header lift cylinder, rod chamber of header tilt cylinder are respectively connected oil tank by pressure relief pipeline;The rodless chamber of header lift cylinder is also connected oil tank by first return pipeline, and first driving pipeline and first return pipeline are respectively provided with first two-position two-way check valve and second two-position two-way check valve, and energy storage pipeline is connected on first return pipeline, and first accumulator is provided on energy storage pipeline;Second driving pipeline connected by the rodless chamber of two header tilt cylinders is connected with hydraulic source by three-position four-way electric proportional directional valve, and balance valve is provided on second driving pipeline.

Description

Technical Field

[0001] This invention relates to the field of agricultural machinery technology, specifically to a header pressure contour control system and agricultural machinery. Background Technology

[0002] The current market for grain combine harvesters suffers from low automation. The flexible headers require close contact with the ground, necessitating constant operator monitoring of ground undulations and adjustments to the header's posture. Harvesting relies entirely on the operator's experience, leading to the following problems: 1. The pressure exerted on the ground by the flexible header depends entirely on the operator's control. In complex terrain, this can easily result in missed harvests or the header hitting the ground, making it difficult to maintain a constant pressure. This results in a short header lifespan, low efficiency, high labor intensity, and a high failure rate. 2. The operator's constant monitoring of ground undulations and adjustments to the header's posture leads to high labor intensity. 3. The header's posture adjustment function is limited, lacking the ability to tilt left or right according to terrain, resulting in poor adaptability. Summary of the Invention

[0003] In order to reduce labor intensity and improve work quality and efficiency, this invention provides a header pressure contour control system and agricultural machinery. During header operation, the header can realize contour function, with high work efficiency and low failure rate.

[0004] The technical solution of the present invention to solve the above-mentioned technical problems is as follows: a cutting platform pressure contour control system for contour control of the cutting platform on the front side of the bridge assembly, wherein the middle part of one side of the cutting platform is rotatably connected to the front side of the bridge assembly via a rotating shaft; including a cutting platform lifting cylinder for driving the cutting platform to rise and fall and a cutting platform tilting cylinder for driving the cutting platform to tilt and swing; the rodless chamber of the cutting platform lifting cylinder and the rodless chamber of the cutting platform tilting cylinder are respectively connected to a hydraulic source through a first driving pipeline and a second driving pipeline; the rod chamber of the cutting platform lifting cylinder and the rod chamber of the cutting platform tilting cylinder are respectively connected to an oil tank through a pressure relief pipeline;

[0005] The rodless chamber of the lifting cylinder of the cutting platform is also connected to the oil tank through the first return oil line. The first drive line and the first return oil line are respectively equipped with a first two-position two-way one-way shut-off valve and a second two-position two-way one-way shut-off valve. The first return oil line is connected to an energy storage line, and the energy storage line is equipped with a first energy storage device.

[0006] There are two tilting cylinders for the cutting table. The second drive pipelines connected to the rodless chambers of the two tilting cylinders are connected to the hydraulic source through a three-position four-way proportional directional valve. A balance valve is provided on the second drive pipeline between the three-position four-way proportional directional valve and the tilting cylinder.

[0007] The beneficial effects of the present invention are: the cutting table pressure contour control system of the present invention can realize the pressure contour function of the cutting table, with high working efficiency and low failure rate.

[0008] Based on the above technical solution, the present invention can be further improved as follows.

[0009] Furthermore, the rodless chamber of the lifting cylinder of the cutting platform is also connected to a throttling pipeline, which is connected to the energy storage pipeline, and a first throttling valve is provided on the throttling pipeline.

[0010] The beneficial effect of adopting the above-mentioned further scheme is that the setting of the first throttle valve can realize the constant flow of throttle between the rodless chamber of the cutting table lifting cylinder and the accumulator.

[0011] Furthermore, a two-position two-way solenoid directional valve is also provided on the energy storage pipeline, and the throttling pipeline is connected to the energy storage pipeline between the two-position two-way solenoid directional valve and the first energy storage device.

[0012] The beneficial effect of adopting the above-mentioned further scheme is that it can realize the on / off control of the rodless chamber of the lifting cylinder of the cutting platform and the accumulator.

[0013] Furthermore, a one-way shut-off valve is also provided on the first drive pipeline downstream of the first two-position two-way one-way shut-off valve.

[0014] Furthermore, one of the second drive pipelines is also equipped with a first pressure compensator. The two second drive pipelines between the balance valve and the three-position four-way proportional directional valve are connected through a compensation pipeline. A shuttle valve is connected to the compensation pipeline, and the third port of the shuttle valve is connected to the feedback port of the first pressure compensator.

[0015] The beneficial effect of adopting the above-mentioned further scheme is that a three-position four-way proportional directional valve and a pressure compensator can be used to achieve proportional control of the oil flow rate in the second drive pipeline.

[0016] Furthermore, the two second drive lines between the balance valve and the cutting table tilting cylinder are connected by a passive contouring line, and the passive contouring line is equipped with a two-position two-way bidirectional shut-off valve.

[0017] The beneficial effects of adopting the above-mentioned further scheme are: when the two-position two-way bidirectional shut-off valve is energized, it can realize the passive contouring function, connect the rodless chambers of the two cutting table tilting cylinders, and the cutting table can rotate freely left and right around the rotating shaft. Since the cutting table is close to the ground, the cutting table can be adjusted left and right according to the undulation of the ground, thus realizing the passive contouring function of the cutting table.

[0018] Furthermore, a second pressure compensator and a third pressure compensator are respectively installed on the first drive pipeline and the first return oil pipeline.

[0019] The beneficial effect of adopting the above-mentioned further solution is that the pressure compensator can accurately proportionally control the flow rate of hydraulic oil flowing through the first two-position two-way check valve and the second two-position two-way check valve.

[0020] Furthermore, it also includes a first controller. The cutting table is a flexible cutting table. The rodless chamber of the cutting table lifting cylinder is also connected to a first pressure sensor. The first pressure sensor is used to detect the pressure value of the cutting table lifting cylinder and send the pressure value to the first controller. The first controller is used to compare the pressure value with a preset pressure value. When the pressure value is less than the preset pressure value, it controls the first two-position two-way check valve to be energized and reversed, so that hydraulic oil enters the rodless chamber of the cutting table lifting cylinder through the first two-position two-way check valve until the pressure value of the rodless chamber of the cutting table lifting cylinder reaches the preset pressure value, and then controls the valve core of the first two-position two-way check valve to return to the neutral position. When the pressure value is greater than the preset pressure value, it controls the second two-position two-way check valve to be energized and reversed, so that the hydraulic oil in the rodless chamber of the cutting table lifting cylinder returns to the oil tank through the second two-position two-way check valve until the pressure value of the rodless chamber of the cutting table lifting cylinder reaches the preset pressure value, and then controls the valve core of the second two-position two-way check valve to return to the neutral position.

[0021] The first controller also controls the valve core opening of the first two-position two-way one-way shut-off valve and the second two-position two-way one-way shut-off valve according to the difference between the pressure value detected by the first pressure sensor and the preset pressure value, so as to maintain the pressure of the cutting table lifting cylinder at the preset pressure value.

[0022] The beneficial effect of adopting the above-mentioned further solution is that it can realize the contour control of the flexible cutting table.

[0023] Furthermore, the flexible cutting table includes a cutting blade, a cutting table body, and a cutting table deflection hydraulic control system. The cutting blade is hinged to the cutting table body. The cutting table deflection hydraulic control system includes a second accumulator, a first two-position two-way directional valve, a pressure sensor, and multiple cutting blade cylinders. The two ends of each cutting blade cylinder are hinged to the cutting table body and the cutting blade, respectively, and drive the cutting blade to swing up and down relative to the cutting table body. The pressure input port of the first two-position two-way directional valve is connected to a hydraulic source through a control pipeline. A control valve is provided on the control pipeline. The pressure output port of the first two-position two-way directional valve is connected to the rod chamber or rodless chamber of multiple cutting blade cylinders through a regulating pipeline. The multiple cutting blade cylinders are connected in parallel on the regulating pipeline through a regulating branch. An energy storage branch is also connected to the regulating pipeline, and a second accumulator is connected to the energy storage branch. A second pressure sensor for monitoring the pressure of the cutting blade cylinders is also provided on the regulating pipeline. A second throttle valve is provided on the regulating pipeline downstream of the pressure output port of the first two-position two-way directional valve.

[0024] The beneficial effect of adopting the above-mentioned further solution is that the cutter deflection of the flexible cutting platform can be further controlled to adapt to different terrain requirements.

[0025] Furthermore, the first two-position two-way directional valve is a two-position two-way one-way shut-off valve, the control valve is a two-position three-way directional valve, the P port of the two-position three-way directional valve is connected to the hydraulic power source, the T port of the two-position three-way directional valve is connected to the oil tank, and the A port of the two-position three-way directional valve is connected to the pressure input port of the first two-position two-way directional valve.

[0026] Furthermore, the first two-position two-way directional valve is a two-position two-way bidirectional shut-off valve, the control valve is a reel control valve, the P port of the reel control valve is connected to a hydraulic power source, the T port of the reel control valve is connected to an oil tank, the A port of the reel control valve is connected to the pressure input port of the first two-position two-way directional valve, the control pipeline is also connected to a reel control branch, the end of the reel branch is connected to a reel cylinder, the reel branch is equipped with a second two-position two-way directional valve, the pressure input end of the second two-position two-way directional valve is connected to the A port of the reel control valve, the pressure output end of the second two-position two-way directional valve is connected to the reel cylinder; the second two-position two-way directional valve is a two-position two-way bidirectional shut-off valve; the reel control valve is a two-position three-way directional valve.

[0027] Furthermore, it also includes a second controller. The second pressure sensor is used to detect the pressure value of the cutting cylinder in real time and send it to the second controller. The second controller is used to convert the pressure value into the deflection value of the cutting table and compare the deflection value with a preset deflection value.

[0028] When the deflection value is less than the preset deflection value, the control valve is de-energized, the first two-position two-way directional valve is energized, and the hydraulic oil of the cutter cylinder and the accumulator returns to the oil tank through the first two-position two-way directional valve; under the action of the accumulator, the pressure of the cutter cylinder gradually decreases, the hardness of the cutter decreases, and the deflection of the cutting table increases until the deflection value reaches the preset deflection value.

[0029] When the deflection value is greater than the preset deflection value, the control valve is energized, the first and second position two-way directional valves are de-energized, and the hydraulic oil enters the rodless chamber of the cutter cylinder through the first and second position two-way directional valves; under the action of the accumulator, the pressure of the cutter cylinder gradually increases, the hardness of the cutter increases, and the deflection of the cutting table decreases until the deflection value reaches the preset deflection value.

[0030] Furthermore, it also includes a third controller. The cutting platform is a rigid cutting platform, and a contour sensor is provided at the bottom of the rigid cutting platform. The contour sensor is used to detect the distance between the cutting platform and the ground and send the distance value to the third controller. The third controller is used to compare the distance value with a preset distance value. When the distance value is less than the preset distance value, it controls the first two-position two-way one-way shut-off valve to be energized and reversed, so that hydraulic oil enters the rodless chamber of the cutting platform lifting cylinder through the first two-position two-way one-way shut-off valve, causing the cutting platform lifting cylinder to drive the rigid cutting platform to rise until the distance value reaches the preset distance value, and then controls the valve core of the first two-position two-way one-way shut-off valve to return to the neutral position. When the distance value is greater than the preset distance value, it controls the second two-position two-way one-way shut-off valve to be energized and reversed, so that the hydraulic oil in the rodless chamber of the cutting platform lifting cylinder returns to the oil tank through the second two-position two-way one-way shut-off valve, causing the cutting platform lifting cylinder to drive the rigid cutting platform to descend until the distance value reaches the preset distance value, and then controls the valve core of the second two-position two-way one-way shut-off valve to return to the neutral position.

[0031] The beneficial effect of adopting the above-mentioned further solution is that it can realize the contour control of the rigid cutting table.

[0032] Furthermore, the two tilting cylinders of the cutting platform are respectively the left tilting cylinder and the right tilting cylinder; the bottom left and right sides of the rigid cutting platform are respectively equipped with a first contour sensor and a second contour sensor. The first contour sensor and the second contour sensor are used to detect the first distance value and the second distance value between the bottom left and right sides of the rigid cutting platform and the ground and send them to the third controller. The third controller is also used to compare the first distance value and the second distance value. When the first distance value is less than the second distance value, it controls the three-position four-way proportional directional valve to be energized and reversed, so that... Hydraulic oil enters the left-side cutting table tilting cylinder through a three-position four-way proportional directional valve, causing the two cutting table tilting cylinders to drive the rigid cutting table to rotate to the right until the first distance value and the second distance value are the same, at which point the three-position four-way proportional directional valve is controlled to return to the neutral position. When the first distance value is greater than the second distance value, the three-position four-way proportional directional valve is energized and reversed, causing hydraulic oil to enter the right-side cutting table tilting cylinder through the three-position four-way proportional directional valve, causing the two cutting table tilting cylinders to drive the rigid cutting table to rotate to the left until the first distance value and the second distance value are the same, at which point the three-position four-way proportional directional valve is controlled to return to the neutral position.

[0033] An agricultural machine includes the aforementioned header pressure contour control system, and further includes a bridge assembly and an agricultural machine body. The bridge assembly is mounted on the front side of the agricultural machine body, and the header is mounted on the bridge assembly. The two ends of the header lifting cylinder are respectively hinged to the bottom of the bridge assembly and the agricultural machine body and are used to drive the bridge assembly and the header on it to rise and fall relative to the agricultural machine body.

[0034] The beneficial effects of the present invention are: the agricultural machinery of the present invention can realize the pressure conformation function of the cutting platform, with high working efficiency and low failure rate. Attached Figure Description

[0035] Figure 1 This is a schematic diagram illustrating the structural principle of the cutting table pressure contour control system of the present invention;

[0036] Figure 2 This is a schematic diagram of the structural principle of the hydraulic control system for the cutting table deflection of the present invention. Figure 1 ;

[0037] Figure 3 This is a schematic diagram of the structural principle of the hydraulic control system for the cutting table deflection of the present invention. Figure 2 ;

[0038] Figure 4 This is a schematic diagram illustrating the structural principle of the combination of the cutting table pressure contour control system and the cutting table deflection hydraulic control system of the present invention.

[0039] Figure 5 This is a three-dimensional structural diagram of the bridge assembly and the cutting platform of the present invention;

[0040] Figure 6 This is a three-dimensional structural diagram of the cutting platform of the present invention;

[0041] Figure 7 This is a three-dimensional structural diagram of the cutting blade on the cutting platform of the present invention;

[0042] Figure 8 This is a schematic diagram of the assembly structure of the cutting cylinder of the present invention;

[0043] Figure 9 This is a schematic diagram of the structure of the agricultural machinery of the present invention.

[0044] The attached diagram lists the components represented by each number as follows:

[0045] 100. Cutting table; 101. Cutting blade; 102. Cutting blade transmission box;

[0046] 200. Cutter cylinder; 201. Second accumulator; 202. First two-position two-way directional valve; 203. Second pressure sensor; 204. Control valve; 206. Second two-position two-way directional valve; 207. Reel cylinder; 208. Second throttle valve;

[0047] 300. Cutter lifting mechanism; 400. Bridge assembly; 500. Agricultural machinery body;

[0048] 600. Cutting board lifting cylinder; 601. First two-position two-way check valve; 602. Second two-position two-way check valve; 603. First accumulator; 604. First throttle valve; 605. Two-position two-way solenoid directional valve; 606. Check valve; 607. Second pressure compensator; 608. Third pressure compensator; 609. First pressure sensor;

[0049] 700. Tilting cylinder for cutting table; 701. First pressure compensator; 702. Three-position four-way electro-proportional directional valve; 703. Shuttle valve; 704. Balance valve; 705. Two-position two-way bidirectional shut-off valve. Detailed Implementation

[0050] The principles and features of the present invention are described below with reference to the accompanying drawings. The examples given are only for explaining the present invention and are not intended to limit the scope of the present invention.

[0051] like Figures 1-4 As shown, this embodiment discloses a cutting platform pressure contour control system for contour control of the cutting platform 100 on the front side of the bridge assembly 400. The middle part of one side of the cutting platform 100 is rotatably connected to the front side of the bridge assembly 400 via a rotating shaft. It includes a cutting platform lifting cylinder 600 for driving the cutting platform 100 to rise and fall, and a cutting platform tilting cylinder 700 for driving the cutting platform 100 to tilt and swing. The rodless chamber of the cutting platform lifting cylinder 600 and the rodless chamber of the cutting platform tilting cylinder 700 are respectively connected to a hydraulic source through a first driving pipeline and a second driving pipeline. The rod chamber of the cutting platform lifting cylinder 600 and the rod chamber of the cutting platform tilting cylinder 700 are respectively connected to an oil tank through a pressure relief pipeline.

[0052] The rodless chamber of the cutting platform lifting cylinder 600 is also connected to the oil tank through the first return oil line. The first drive line and the first return oil line are respectively equipped with a first two-position two-way one-way shut-off valve 601 and a second two-position two-way one-way shut-off valve 602. The first return oil line is connected to an energy storage line, and the energy storage line is equipped with a first energy accumulator 603.

[0053] There are two cutting table tilting cylinders 700. The second drive pipelines connected to the rodless chambers of the two cutting table tilting cylinders 700 are connected to the hydraulic source through a three-position four-way proportional directional valve 702. A balance valve 704 is provided on the second drive pipeline between the three-position four-way proportional directional valve 702 and the cutting table tilting cylinder 700.

[0054] like Figure 1 and Figure 4 As shown, in this embodiment, the rodless chamber of the cutting platform lifting cylinder 600 is also connected to a throttling pipeline, which is connected to the energy storage pipeline. A first throttling valve 604 is provided on the throttling pipeline. The first throttling valve allows for constant throttling between the rodless chamber of the cutting platform lifting cylinder and the energy storage device.

[0055] like Figure 1 and Figure 4 As shown, in this embodiment, the energy storage pipeline is also equipped with a two-position two-way solenoid directional valve 605, and the throttling pipeline is connected to the energy storage pipeline between the two-position two-way solenoid directional valve 605 and the first accumulator 603. This enables the on / off control of the rodless chamber of the cutting platform lifting cylinder and the accumulator.

[0056] like Figure 1 and Figure 4 As shown, in this embodiment, a one-way shut-off valve 606 is also provided on the first drive pipeline downstream of the first two-position two-way one-way shut-off valve 601.

[0057] like Figure 1 and Figure 4 As shown, in this embodiment, one of the second drive pipelines is also equipped with a first pressure compensator 701. The two second drive pipelines between the balance valve 704 and the three-position four-way proportional directional valve 702 are connected through a compensation pipeline. A shuttle valve 703 is connected to the compensation pipeline, and the third port of the shuttle valve 703 is connected to the feedback port of the first pressure compensator 701. The three-position four-way proportional directional valve and the pressure compensator can be used to achieve proportional control of the oil flow rate in the second drive pipeline.

[0058] like Figure 1 and Figure 4 As shown, in this embodiment, the two second drive lines between the balance valve 704 and the cutting table tilting cylinder 700 are connected through a passive contouring line. A two-position two-way bidirectional shut-off valve 705 is provided on the passive contouring line. When the two-position two-way bidirectional shut-off valve is energized, the passive contouring function is realized, connecting the rodless chambers of the two cutting table tilting cylinders. The cutting table can rotate freely left and right around its axis. Since the cutting table is close to the ground, it can adjust its left and right rotation according to the ground's undulations, thus realizing the passive contouring function of the cutting table.

[0059] like Figure 1 and Figure 4 As shown, in this embodiment, the first drive pipeline and the first return oil pipeline are respectively equipped with a second pressure compensator 607 and a third pressure compensator 608. The pressure compensators enable precise proportional control of the hydraulic oil flow through the first two-position two-way check valve and the second two-position two-way check valve.

[0060] Specifically, in this embodiment, the cutting platform pressure contour control system integrates all valves into a control valve group. Hydraulic oil enters the rodless chamber of the cutting platform lifting cylinder 600 through the control valve group's P port, via the second pressure compensator 607, the first two-position two-way check valve 602, and the check valve 606. Hydraulic oil in the rod chamber of the cutting platform lifting cylinder 600 flows back to the oil tank through the first return oil line. The rodless chamber of the cutting platform lifting cylinder 600 is also connected to the control valve group's return oil T port through the third pressure compensator 608 and the second two-position two-way check valve 602. The rodless chamber of the cutting platform lifting cylinder 600 can be connected to the first accumulator 603 through the first throttle valve 604 or the two-position two-way solenoid directional valve 605. The hydraulic oil at port P of the control valve group is connected to the rodless chamber of the cutting table tilting cylinder 700 through the first pressure compensator 701, the three-position four-way proportional directional valve 702, and the two balance valves 704. The rodless chamber of the cutting table tilting cylinder 700 is connected to the system return oil.

[0061] The lifting and lowering of the cutting platform is controlled by a pressure contour control system: When the first two-position two-way check valve 601 is energized, the pressure oil flows through the second pressure compensator 607, the first two-position two-way check valve 601, and the check valve 606 into the rodless chamber of the lifting cylinder 600. The piston rod of the lifting cylinder 600 extends, and the cutting platform rises. After the action is completed, the first two-position two-way check valve 601 is de-energized, and the hydraulic oil in the rodless chamber of the lifting cylinder 600 is locked by the check valve 606 and the second two-position two-way check valve 602, keeping the cutting platform in its original position. The lifting speed of the cutting platform can be controlled by the magnitude of the control signal from the first two-position two-way check valve 601, and is independent of the cutting platform load. When the second 2-position 2-way check valve 602 is energized and reversed, the oil in the rodless chamber of the header lifting cylinder 600 returns to the oil tank through the third pressure compensator 608 and the second 2-position 2-way check valve 602 under the action of the header's gravity. The piston rod of the header lifting cylinder 600 retracts, and the header descends. After the operation is completed, the second 2-position 2-way check valve 602 is de-energized, and the oil in the rodless chamber of the header lifting cylinder 600 is locked by the check valve 601 and the second 2-position 2-way check valve 602, and the header remains in its original position. The descending speed of the header can be controlled by the magnitude of the control signal of the second 2-position 2-way check valve 602, and is independent of the header load.

[0062] The left and right tilting motion of the cutting table is controlled by the cutting table pressure contour control system: When the three-position four-way proportional directional valve 702 is energized and reversed to the left position, hydraulic oil enters the rodless chamber of the left cutting table tilting cylinder 700 through the first pressure compensator 701, the left position of the three-position four-way proportional directional valve 702, and the balance valve 704. The piston rod of the left cutting table tilting cylinder 700 extends, and the cutting table 100 rotates around the central axis. The piston rod of the right cutting table tilting cylinder 700 is forced to retract, and the oil in the rodless chamber of the right cutting table tilting cylinder 700 returns to the oil tank through the balance valve 704 and the left position of the three-position four-way proportional directional valve 702; the cutting table tilts to the right. After the action is completed, the three-position four-way proportional directional valve 702 is de-energized, the cutting table tilting cylinder 700 is locked by the two balance valves 704, and the cutting table remains in its original position. When the three-position four-way proportional directional valve 702 is energized and reverses to the right position, pressurized oil flows through the first pressure compensator 701, the right position of the three-position four-way proportional directional valve 702, and the balance valve 704 into the rodless chamber of the right-side tilting cylinder 700. The piston rod of the right-side tilting cylinder 700 extends, and the cutting platform 100 rotates around its center. The piston rod of the left-side tilting cylinder 700 is forced to retract, and the oil in the rodless chamber of the left-side tilting cylinder 700 returns to the oil tank through the balance valve 704 and the right position of the three-position four-way proportional directional valve 702. The cutting platform 100 tilts to the left. After the operation is completed, the three-position four-way proportional directional valve 702 is de-energized, and the tilting cylinder 700 is locked by the two balance valves 704, keeping the cutting platform in its original position. The speed of the left and right tilting of the cutting platform can be controlled by the magnitude of the control signal of the three-position four-way proportional directional valve 702, and is independent of the load on the cutting platform.

[0063] Harvester Operation Mode and Transfer Transportation Mode: When the 2-position 2-way solenoid valve 605 is de-energized, the rodless chamber of the header lifting cylinder 600 is connected to the first accumulator 603 via the first throttle valve 604. The buffering effect of the first accumulator 603 on the header 100 is limited by the first throttle valve 604, resulting in a more stable header 100 posture and faster movements. This is the harvester operation mode. When the 2-position 2-way solenoid valve 605 is energized, the rodless chamber of the header lifting cylinder 600 is directly connected to the first accumulator 603 via the 2-position 2-way solenoid valve 605. The buffering effect of the first accumulator 603 on the header 100 is more significantly limited, resulting in a more pronounced buffering effect and less impact during combine harvester transfer transportation. This is the transfer transportation mode.

[0064] When the cutting table 100 is a flexible cutting table, the cutting table pressure contour control system in this embodiment further includes a first controller. The rodless chamber of the cutting table lifting cylinder 600 is also connected to a first pressure sensor 609. The first pressure sensor 609 is used to detect the pressure value of the cutting table lifting cylinder 600 and send the pressure value to the first controller. The first controller is used to compare the pressure value with a preset pressure value. When the pressure value is less than the preset pressure value, it controls the first two-position two-way one-way shut-off valve 601 to be energized and reversed, allowing hydraulic oil to enter the rodless chamber of the cutting table lifting cylinder 600 through the first two-position two-way one-way shut-off valve 601 until the pressure value in the rodless chamber of the cutting table lifting cylinder 600 reaches the preset pressure value. Then, it controls the valve core of the first two-position two-way one-way shut-off valve 601 to return to center. When the pressure value is greater than the preset pressure value, the second two-position two-way one-way shut-off valve 602 is energized and reversed, so that the hydraulic oil in the rodless chamber of the cutting platform lifting cylinder 600 returns to the oil tank through the second two-position two-way one-way shut-off valve 602 until the pressure value in the rodless chamber of the cutting platform lifting cylinder 600 reaches the preset pressure value, and then the valve core of the second two-position two-way one-way shut-off valve 602 is controlled to return to the neutral position; the first controller also controls the valve core opening of the first two-position two-way one-way shut-off valve 601 and the second two-position two-way one-way shut-off valve 602 according to the difference between the pressure value detected by the first pressure sensor 609 and the preset pressure value, so as to ultimately maintain the pressure of the cutting platform lifting cylinder 600 at the preset pressure value. At this time, the supporting force of the ground on the cutting platform will remain unchanged, realizing the pressure conformal function of the cutting platform in the forward direction.

[0065] The flexible cutting table includes both adjustable-flexibility and non-adjustable-flexibility cutting tables. The cutting table pressure contour control system of this embodiment is applicable not only to flexible cutting tables with adjustable-flexibility cutting tables but also to those with non-adjustable-flexibility cutting tables. For flexible cutting tables with adjustable-flexibility cutting tables, this embodiment also provides an optional control scheme, as detailed below:

[0066] like Figure 2 , Figure 3 , Figures 6-8As shown, the flexible cutting table in this embodiment includes a cutting blade 101, a cutting table body, and a cutting table deflection hydraulic control system. The cutting blade 101 is hinged to the cutting table body. The cutting table deflection hydraulic control system includes a second accumulator 201, a first two-position two-way directional valve 202, a second pressure sensor 203, and multiple cutting blade cylinders 200. The two ends of each cutting blade cylinder 200 are hinged to the cutting table body and the cutting blade 101, respectively, and drive the cutting blade 101 to swing up and down relative to the cutting table body. The pressure input port of the first two-position two-way directional valve 202 is connected to a hydraulic power source through a control pipeline. A control valve 204 is installed on the pipeline. The pressure output port of the first two-position two-way directional valve 202 is connected to the rod-side or rodless-side chambers of multiple cutting cylinders 200 via regulating pipelines. Multiple cutting cylinders 200 are connected in parallel on the regulating pipeline via regulating branches. An energy storage branch is also connected to the regulating pipeline, and a second accumulator 201 is connected to the energy storage branch. A second pressure sensor 203 for monitoring the pressure of the cutting cylinders 200 is also installed on the regulating pipeline. A second throttle valve 208 is installed on the regulating pipeline downstream of the pressure output port of the first two-position two-way directional valve 202. This allows for further control of the cutting blade deflection of the flexible cutting platform to adapt to different terrain conditions. To achieve stable and effective driving of the cutting blade 101, multiple cutting cylinders 200 are evenly distributed, each a single-acting plunger cylinder, and the oil ports of multiple cutting cylinders 200 are connected in parallel. The pressure of the cutting cylinder 200 directly reflects the deflection of the cutting table 100; the higher the pressure of the cutting cylinder 200, the smaller the deflection of the cutting table 100, and the lower the pressure of the cutting cylinder 200, the greater the deflection of the cutting table 100.

[0067] like Figure 2 As shown, one possible embodiment of the first two-position two-way directional valve 202 is that the first two-position two-way directional valve 202 is a two-position two-way one-way shut-off valve, the control valve 204 is a two-position three-way directional valve, the P port of the two-position three-way directional valve is connected to a hydraulic power source, the T port of the two-position three-way directional valve is connected to an oil tank, and the A port of the two-position three-way directional valve is connected to the pressure input port of the first two-position two-way directional valve.

[0068] like Figure 3As shown, another optional embodiment of the first two-position two-way directional valve 202 is that the first two-position two-way directional valve 202 is a two-position two-way bidirectional shut-off valve, the control valve 204 is a reel control valve, the P port of the reel control valve is connected to a hydraulic power source, the T port of the reel control valve is connected to an oil tank, the A port of the reel control valve is connected to the pressure input port of the first two-position two-way directional valve 202, and a reel control branch is also connected to the control pipeline. The end of the reel branch is connected to a reel cylinder 207, and a second two-position two-way directional valve 206 is provided on the reel branch. The pressure input end of the second two-position two-way directional valve 206 is connected to the A port of the reel control valve, and the pressure output end of the second two-position two-way directional valve 206 is connected to the reel cylinder 207; the second two-position two-way directional valve 206 is a two-position two-way bidirectional shut-off valve; the reel control valve is a two-position three-way directional valve.

[0069] Specifically, such as Figures 6-8 As shown, in this embodiment, the cutter 101 is hinged to the cutting table 100 via multiple cutter lifting mechanisms 300. The cutter lifting mechanisms 300 are arranged front to back, with their front ends fixedly connected to the cutter 101 and their rear ends hinged to the cutting table 100. Each cutter lifting mechanism is equipped with a corresponding cutter cylinder, the cylinder barrel of which is hinged to the cutting table, and the piston rod of which is hinged to the cutter lifting mechanism. The cutter 101 is located at the front of the cutting table 100, and the cutter transmission box 102 is located on the left side of the cutting table 100. It is responsible for transmitting power to the cutter 101. Since the cutter 101 is a flexible structure and its deflection is controlled by the hydraulic control system for the deflection of the cutting table, the cutter transmission box 102 will move up and down with the cutter 101, resulting in different weights at different positions of the cutter 101. Since the cutter lifting mechanism 300 at different positions of the cutter 101 bears different forces, the cutter cylinder 200 corresponding to each cutter lifting mechanism 300 can adopt different cylinder diameters to achieve synchronous action.

[0070] The above-mentioned cutting table deflection hydraulic control system also includes a second controller. The second pressure sensor 203 is used to detect the pressure value of the cutting cylinder 200 in real time and send it to the second controller. The second controller is used to convert the pressure value into the deflection value of the cutting table 100 (wherein the conversion process can be implemented using existing technology) and compare the deflection value with a preset deflection value.

[0071] When the deflection value is less than the preset deflection value, the control valve 204 is de-energized, the first two-position two-way directional valve 202 is energized, and the hydraulic oil of the cutter cylinder 200 and the second accumulator 201 returns to the oil tank through the first two-position two-way directional valve 202; under the action of the second accumulator 201, the pressure of the cutter cylinder 200 gradually decreases, the hardness of the cutter 101 decreases, and the deflection of the cutting table 100 increases until the deflection value reaches the preset deflection value;

[0072] When the deflection value is greater than the preset deflection value, the control valve 204 is energized, the first two-position two-way directional valve 202 is de-energized, and the hydraulic oil enters the rodless chamber of the cutter cylinder 200 through the first two-position two-way directional valve 202; under the action of the second accumulator 201, the pressure of the cutter cylinder 200 gradually increases, the hardness of the cutter 101 increases, and the deflection of the cutting table 100 decreases until the deflection value reaches the preset deflection value.

[0073] Depending on different terrain conditions, the operator can infinitely adjust the deflection value of the header, or set n different header deflection values ​​in the operating system. The operator only needs to judge the working conditions and select different modes; the system automatically controls the reel control valve and the first / second-position two-way directional valve 202, automatically matching different pressure values ​​of the cutter cylinder 200. This embodiment, by setting pressure sensors, a two-position two-way directional valve, and cutter cylinders, allows for free adjustment of the cutter's hardness to adapt to different terrain requirements. Furthermore, it can control the header to switch between a flexible and rigid header, making it highly adaptable.

[0074] In this embodiment, the cutting table pressure contour control system is applicable not only to contour control of flexible cutting tables, but also to contour control of rigid cutting tables.

[0075] When the cutting platform 100 is a rigid cutting platform, the cutting platform pressure contour control system also includes a third controller. A contour sensor is provided at the bottom of the rigid cutting platform. The contour sensor detects the distance between the cutting platform 100 and the ground and sends the distance value to the third controller. The third controller compares the distance value with a preset distance value. When the distance value is less than the preset distance value, it controls the first two-position two-way one-way shut-off valve 601 to be energized and reversed, allowing hydraulic oil to enter the rodless chamber of the cutting platform lifting cylinder 600 through the first two-position two-way one-way shut-off valve 601. The hydraulic cylinder 600 drives the rigid cutting table to rise until the distance reaches the preset distance value, and controls the valve core of the first two-position two-way one-way shut-off valve 601 to return to the neutral position. When the distance value is greater than the preset distance value, the hydraulic cylinder 602 is energized and reversed, so that the hydraulic oil in the rodless chamber of the hydraulic cylinder 600 returns to the oil tank through the second two-position two-way one-way shut-off valve 602, and the hydraulic cylinder 600 drives the rigid cutting table to descend until the distance reaches the preset distance value, and controls the valve core of the second two-position two-way one-way shut-off valve 602 to return to the neutral position.

[0076] The two tilting cylinders 700 of the cutting platform are the left tilting cylinder and the right tilting cylinder, respectively. A first contour sensor and a second contour sensor are respectively installed on the left and right sides of the bottom of the rigid cutting platform. The first and second contour sensors are used to detect a first distance value and a second distance value between the left and right sides of the bottom of the rigid cutting platform and the ground, respectively, and send these values ​​to a third controller. The third controller is used to compare the first and second distance values ​​with preset distance values. When both the first and second distance values ​​are less than the preset distance value, it controls the first two-position two-way one-way shut-off valve 601 to be energized and reversed, allowing hydraulic oil to enter the cutting platform through the first two-position two-way one-way shut-off valve 601. The rodless chamber of the lifting cylinder 600 drives the rigid cutting table to rise until the first distance value and the second distance value reach a preset distance value, controlling the valve core of the first two-position two-way one-way shut-off valve 601 to return to the neutral position; when the first distance value and the second distance value are greater than the preset distance value, the second two-position two-way one-way shut-off valve 602 is energized and reversed, causing the hydraulic oil in the rodless chamber of the lifting cylinder 600 to return to the oil tank through the second two-position two-way one-way shut-off valve 602, causing the lifting cylinder 600 to drive the rigid cutting table to fall until at least one of the first distance value and the second distance value reaches the preset distance value, controlling the valve core of the second two-position two-way one-way shut-off valve 602 to return to the neutral position.

[0077] The third controller is also used to compare the first distance value and the second distance value. When the first distance value is less than the second distance value, it controls the three-position four-way proportional directional valve 702 to be energized and reversed, so that hydraulic oil enters the left-side cutting table tilting cylinder through the three-position four-way proportional directional valve 702, causing the two cutting table tilting cylinders 700 to drive the rigid cutting table to rotate to the right until the first distance value and the second distance value are the same, and then controls the three-position four-way proportional directional valve 702 to return to the neutral position. When the first distance value is greater than the second distance value, it controls the three-position four-way proportional directional valve 702 to be energized and reversed, so that hydraulic oil enters the right-side cutting table tilting cylinder through the three-position four-way proportional directional valve 702, so that the two cutting table tilting cylinders drive the rigid cutting table to rotate to the left until the first distance value and the second distance value are the same, and then controls the three-position four-way proportional directional valve 702 to return to the neutral position.

[0078] The header pressure contour control system described in this embodiment can realize the header pressure contour function and passive contour function during header operation, with high working efficiency and low failure rate; the header height can be automatically judged and adjusted according to the terrain, and the stubble height is consistent, which can avoid the risk of easy collision between the header and the ground; the harvester operation mode and the transfer transportation mode can be freely switched; the header action response is fast in operation mode, and the header buffering effect is good in transfer mode.

[0079] This embodiment also provides an agricultural machine, such as Figure 5 and Figure 9 As shown, the device includes the aforementioned header pressure contouring control system, as well as a bridge assembly 400 and an agricultural machinery body 500. The bridge assembly 400 is mounted on the front side of the agricultural machinery body 500, and the header 100 is mounted on the bridge assembly 400. The two ends of the header lifting cylinder 600 are hinged to the bottom of the bridge assembly 400 and the agricultural machinery body 500, respectively, and are used to drive the bridge assembly 400 and the header 100 on it to rise and fall relative to the agricultural machinery body 500. Two header tilting cylinders 700 are respectively mounted on the left and right sides of the front of the bridge assembly 400. The header tilting cylinders 700 are arranged vertically and are hinged to the header 100 and the bridge assembly 400, respectively, and drive the header 100 to swing left and right up and down relative to the bridge assembly 400. The agricultural machinery of this embodiment can achieve header pressure contouring function, with high working efficiency and low failure rate.

[0080] In the description of this invention, it should be understood that the terms "front", "rear", "left", "right", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0081] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0082] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0083] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0084] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0085] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A cutting table pressure contour control system for contour control of the cutting table on the front side of a bridge assembly, wherein the middle part of one side of the cutting table is rotatably connected to the front side of the bridge assembly via a rotating shaft; characterized in that, It includes a lifting cylinder for driving the cutting platform to rise and fall, and a tilting cylinder for driving the cutting platform to tilt and swing; the rodless chamber of the lifting cylinder and the rodless chamber of the tilting cylinder are respectively connected to a hydraulic source through a first driving line and a second driving line; the rod chamber of the lifting cylinder and the rod chamber of the tilting cylinder are respectively connected to an oil tank through a pressure relief line. The rodless chamber of the lifting cylinder of the cutting platform is also connected to the oil tank through the first return oil line. The first drive line and the first return oil line are respectively equipped with a first two-position two-way one-way shut-off valve and a second two-position two-way one-way shut-off valve. The first return oil line is connected to an energy storage line, and the energy storage line is equipped with a first energy storage device. There are two tilting cylinders for the cutting table. The second drive pipelines connected to the rodless chambers of the two tilting cylinders are connected to the hydraulic source through a three-position four-way proportional directional valve. A balance valve is provided on the second drive pipeline between the three-position four-way proportional directional valve and the tilting cylinder. A one-way shut-off valve is also provided on the first drive pipeline downstream of the first two-position two-way one-way shut-off valve; One of the second drive lines is also equipped with a first pressure compensator. The two second drive lines between the balance valve and the three-position four-way proportional directional valve are connected through a compensation line. A shuttle valve is connected to the compensation line, and the third port of the shuttle valve is connected to the feedback port of the first pressure compensator.

2. The cutting table pressure contour control system according to claim 1, characterized in that, The rodless chamber of the lifting cylinder of the cutting platform is also connected to a throttling pipeline, which is connected to the energy storage pipeline, and a first throttling valve is provided on the throttling pipeline.

3. The cutting table pressure contour control system according to claim 2, characterized in that, The energy storage pipeline is also equipped with a two-position two-way solenoid directional valve, and the throttling pipeline is connected to the energy storage pipeline between the two-position two-way solenoid directional valve and the first energy storage device.

4. The cutting table pressure contour control system according to claim 1, characterized in that, The two second drive lines between the balance valve and the cutting table tilting cylinder are connected by a passive contouring line, and the passive contouring line is equipped with a two-position two-way bidirectional shut-off valve.

5. The cutting table pressure contour control system according to claim 1, characterized in that, The first drive line and the first return line are also equipped with a second pressure compensator and a third pressure compensator, respectively.

6. The cutting table pressure contour control system according to claim 1, characterized in that, The system also includes a first controller. The cutting platform is a flexible cutting platform. The rodless chamber of the cutting platform lifting cylinder is connected to a first pressure sensor. The first pressure sensor is used to detect the pressure value of the cutting platform lifting cylinder and send the pressure value to the first controller. The first controller is used to compare the pressure value with a preset pressure value. When the pressure value is less than the preset pressure value, the first two-position two-way check valve is energized and reversed, allowing hydraulic oil to enter the rodless chamber of the cutting platform lifting cylinder through the first two-position two-way check valve until the pressure value of the rodless chamber of the cutting platform lifting cylinder reaches the preset pressure value. Then, the valve core of the first two-position two-way check valve is controlled to return to the neutral position. When the pressure value is greater than the preset pressure value, the second two-position two-way check valve is energized and reversed, allowing the hydraulic oil in the rodless chamber of the cutting platform lifting cylinder to return to the oil tank through the second two-position two-way check valve until the pressure value of the rodless chamber of the cutting platform lifting cylinder reaches the preset pressure value. Then, the valve core of the second two-position two-way check valve is controlled to return to the neutral position. The first controller also controls the valve core opening of the first two-position two-way one-way shut-off valve and the second two-position two-way one-way shut-off valve according to the difference between the pressure value detected by the first pressure sensor and the preset pressure value, so as to maintain the pressure of the cutting table lifting cylinder at the preset pressure value.

7. The cutting table pressure contour control system according to claim 6, characterized in that, The flexible cutting platform includes a cutting blade, a cutting platform body, and a hydraulic control system for cutting platform deflection. The cutting blade is hinged to the cutting platform body. The hydraulic control system for cutting platform deflection includes a second accumulator, a first two-position two-way directional valve, a pressure sensor, and multiple cutting blade cylinders. The two ends of each cutting blade cylinder are hinged to the cutting platform body and the cutting blade, respectively, and drive the cutting blade to swing up and down relative to the cutting platform body. The pressure input port of the first two-position two-way directional valve is connected to a hydraulic power source through a control pipeline. A control valve is provided on the control pipeline. The pressure output port of the first two-position two-way directional valve is connected to the rod chamber or rodless chamber of each of the multiple cutting blade cylinders through a regulating pipeline. The multiple cutting blade cylinders are connected in parallel on the regulating pipeline through a regulating branch. An energy storage branch is also connected to the regulating pipeline, and a second accumulator is connected to the energy storage branch. A second pressure sensor for monitoring the pressure of the cutting blade cylinders is also provided on the regulating pipeline. A throttle valve is provided on the regulating pipeline downstream of the pressure output port of the first two-position two-way directional valve.

8. The cutting table pressure contour control system according to claim 7, characterized in that, The first two-position two-way directional valve is a two-position two-way one-way shut-off valve, the control valve is a two-position three-way directional valve, the P port of the two-position three-way directional valve is connected to the hydraulic power source, the T port of the two-position three-way directional valve is connected to the oil tank, and the A port of the two-position three-way directional valve is connected to the pressure input port of the first two-position two-way directional valve.

9. The cutting table pressure contour control system according to claim 7, characterized in that, The first two-position two-way directional valve is a two-position two-way bidirectional shut-off valve. The control valve is a reel control valve. The P port of the reel control valve is connected to a hydraulic power source, the T port is connected to an oil tank, and the A port is connected to the pressure input port of the first two-position two-way directional valve. A reel control branch is also connected to the control pipeline. The end of the reel branch is connected to a reel cylinder. A second two-position two-way directional valve is provided on the reel branch. The pressure input end of the second two-position two-way directional valve is connected to the A port of the reel control valve, and the pressure output end of the second two-position two-way directional valve is connected to the reel cylinder. The second two-position two-way directional valve is a two-position two-way bidirectional shut-off valve. The reel control valve is a two-position three-way directional valve.

10. The cutting table pressure contour control system according to claim 7, characterized in that, It also includes a second controller, wherein the second pressure sensor is used to detect the pressure value of the cutting cylinder in real time and send it to the second controller, and the second controller is used to convert the pressure value into the deflection value of the cutting table and compare the deflection value with a preset deflection value; When the deflection value is less than the preset deflection value, the control valve is de-energized, the first two-position two-way directional valve is energized, and the hydraulic oil of the cutter cylinder and the accumulator returns to the oil tank through the first two-position two-way directional valve; under the action of the accumulator, the pressure of the cutter cylinder gradually decreases, the hardness of the cutter decreases, and the deflection of the cutting table increases until the deflection value reaches the preset deflection value. When the deflection value is greater than the preset deflection value, the control valve is energized, the first and second position two-way directional valves are de-energized, and the hydraulic oil enters the rodless chamber of the cutter cylinder through the first and second position two-way directional valves; under the action of the accumulator, the pressure of the cutter cylinder gradually increases, the hardness of the cutter increases, and the deflection of the cutting table decreases until the deflection value reaches the preset deflection value.

11. The cutting table pressure contour control system according to claim 1, characterized in that, The system also includes a third controller. The cutting platform is a rigid cutting platform, and a contour sensor is installed at the bottom of the rigid cutting platform. The contour sensor is used to detect the distance between the rigid cutting platform and the ground and send the distance value to the third controller. The third controller is used to compare the distance value with a preset distance value. When the distance value is less than the preset distance value, the first two-position two-way one-way shut-off valve is energized and reversed, allowing hydraulic oil to enter the rodless chamber of the cutting platform lifting cylinder through the first two-position two-way one-way shut-off valve, causing the cutting platform lifting cylinder to drive the rigid cutting platform to rise until the distance value reaches the preset distance value, and then the valve core of the first two-position two-way one-way shut-off valve is controlled to return to the neutral position. When the distance value is greater than the preset distance value, the second two-position two-way one-way shut-off valve is energized and reversed, allowing the hydraulic oil in the rodless chamber of the cutting platform lifting cylinder to return to the oil tank through the second two-position two-way one-way shut-off valve, causing the cutting platform lifting cylinder to drive the rigid cutting platform to descend until the distance value reaches the preset distance value, and then the valve core of the second two-position two-way one-way shut-off valve is controlled to return to the neutral position.

12. The cutting table pressure contour control system according to claim 11, characterized in that, The two tilting cylinders for the cutting platform are the left tilting cylinder and the right tilting cylinder, respectively. A first contour sensor and a second contour sensor are respectively installed on the left and right sides of the bottom of the rigid cutting platform. The first and second contour sensors are used to detect a first distance value and a second distance value between the left and right sides of the bottom of the rigid cutting platform and the ground, respectively, and send these values ​​to a third controller. The third controller is also used to compare the first and second distance values. When the first distance value is less than the second distance value, it controls the three-position four-way proportional directional valve to energize and reverse the hydraulic pressure. Oil enters the left-side cutting table tilting cylinder through a three-position four-way proportional directional valve, causing the two cutting table tilting cylinders to drive the rigid cutting table to rotate to the right until the first distance value and the second distance value are the same, at which point the three-position four-way proportional directional valve is controlled to return to the neutral position. When the first distance value is greater than the second distance value, the three-position four-way proportional directional valve is energized and reversed, allowing hydraulic oil to enter the right-side cutting table tilting cylinder through the three-position four-way proportional directional valve, causing the two cutting table tilting cylinders to drive the rigid cutting table to rotate to the left until the first distance value and the second distance value are the same, at which point the three-position four-way proportional directional valve is controlled to return to the neutral position.

13. An agricultural machine, characterized in that, The header pressure contour control system according to any one of claims 1 to 12 further includes a bridge assembly and an agricultural machinery body, wherein the bridge assembly is mounted on the front side of the agricultural machinery body, the header is mounted on the bridge assembly, and the two ends of the header lifting cylinder are respectively hinged to the bottom of the bridge assembly and the agricultural machinery body and are used to drive the bridge assembly and the header on it to rise and fall relative to the agricultural machinery body.

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