阅读说明：本技术 一种用于农业收割设备中割台仿形的液压控制系统及其控制方法 (Hydraulic control system for profiling of cutting table in agricultural harvesting equipment and control method thereof ) 是由 肖敏 代宝鹏 肖前龙 戴明慧 陈晨 敖鹍 曾林 于 2021-09-23 设计创作，主要内容包括：本发明提供一种用于农业收割设备中割台仿形的液压控制系统,包括液压泵、油箱、供油油路、举升油缸、回油油路和推力调节油路；所述举升油缸用于控制割台的上升或下降,且举升油缸的有杆腔室和无杆腔室之间设有连接油路；所述供油油路用于连接液压泵和举升油缸的无杆腔室；所述回油油路用于连接油箱和举升油缸的有杆腔室；所述推力调节油路用于连接举升油缸与液压泵或举升油缸与油箱。本发明既能通过液压泵、油箱、供油油路、举升油缸和回油油路的相互配合实施割台的主动仿形控制,又能通过控制连接油路使举升油缸的有杆腔室和无杆腔室形成差动连接实施割台的被动仿形控制,提高了系统的操作的灵活性。(The invention provides a hydraulic control system for profiling a cutting table in agricultural harvesting equipment, which comprises a hydraulic pump, an oil tank, an oil supply oil way, a lifting oil cylinder, an oil return oil way and a thrust adjusting oil way, wherein the hydraulic pump is connected with the oil tank; the lifting oil cylinder is used for controlling the header to ascend or descend, and a connecting oil way is arranged between a rod chamber and a rodless chamber of the lifting oil cylinder; the oil supply oil path is used for connecting the hydraulic pump and a rodless cavity of the lifting oil cylinder; the oil return oil way is used for connecting the oil tank and a rod chamber of the lifting oil cylinder; and the thrust adjusting oil way is used for connecting the lifting oil cylinder with the hydraulic pump or the lifting oil cylinder with the oil tank. The invention can implement the active profiling control of the header by the mutual matching of the hydraulic pump, the oil tank, the oil supply circuit, the lifting oil cylinder and the oil return circuit, and can also implement the passive profiling control of the header by controlling the connecting oil circuit to enable the rod cavity and the rodless cavity of the lifting oil cylinder to form differential connection, thereby improving the flexibility of the operation of the system.)

1. The utility model provides a hydraulic control system that is arranged in agricultural harvesting equipment header profile modeling which characterized in that: the hydraulic control system comprises a hydraulic pump, an oil tank, an oil supply oil way, a lifting oil cylinder, an oil return oil way and a thrust adjusting oil way;

the lifting oil cylinder is used for controlling the header to ascend or descend and comprises a rod cavity and a rodless cavity, a connecting oil way is arranged between the rod cavity and the rodless cavity, and a switch valve is arranged on the connecting oil way;

the oil supply circuit is used for connecting the hydraulic pump and the rodless cavity of the lifting oil cylinder, a first flow control mechanism and a one-way valve are arranged on the oil supply circuit, and oil is pumped by the hydraulic pump and is conveyed into the rodless cavity of the lifting oil cylinder through the first flow control mechanism and the one-way valve;

the oil return circuit is used for connecting the oil tank and a rod chamber of the lifting oil cylinder, a second flow control mechanism is arranged on the oil return circuit, and oil flows back into the oil tank through the second flow control mechanism;

the thrust adjusting oil way is connected with the lifting oil cylinder, the hydraulic pump and the oil tank, and a pressure reducing overflow piece is arranged on the thrust adjusting oil way.

2. The hydraulic control system of claim 1, wherein: the oil supply oil way, the oil return oil way and the thrust adjusting oil way are all connected with the communicating oil way.

3. The hydraulic control system of claim 1, wherein: the first flow control mechanism and the second flow control mechanism are both arranged to be proportional electromagnetic directional valves with compensators.

4. The hydraulic control system of claim 1, wherein: the first flow control mechanism and the second flow control mechanism are both arranged into a combined structure of a proportional electromagnetic directional valve and a pressure compensation valve.

5. The hydraulic control system of claim 1, wherein: the switch valve is set to be an electromagnetic valve or a manual valve.

6. The hydraulic control system of claim 1, wherein: the pressure reducing overflow piece is of a combined structure of a pressure reducing valve and an overflow valve.

7. The hydraulic control system of claim 1, wherein: the pressure reducing overflow piece is arranged as an electric proportional pressure reducing overflow valve.

8. The hydraulic control system according to any one of claims 1 to 7, characterized in that: the hydraulic lifting device further comprises a pressure sensor for detecting the hydraulic pressure in the lifting oil cylinder.

9. A hydraulic control method for profiling a header in agricultural harvesting equipment is characterized by comprising the following steps: the specific process of header active profiling using the hydraulic control system of claim 8 is as follows:

when the height of the header from the ground is smaller than the preset height, a first proportional electromagnetic directional valve and a hydraulic pump are started, the hydraulic pump pumps oil, the oil sequentially enters a rodless cavity of a lifting oil cylinder through the first proportional electromagnetic directional valve, a first pressure compensation valve and a one-way valve, the lifting oil cylinder lifts, and meanwhile, the oil in a rod cavity of the lifting oil cylinder flows back to an oil tank through an electric proportional pressure reduction overflow valve; when the sensors around the header detect that the header rises to the preset height, the first proportional electromagnetic directional valve loses electricity, and meanwhile, oil in the rodless cavity of the lifting oil cylinder is in a pressure maintaining state under the action of the one-way valve, so that the header is stabilized at the preset height, and the purpose of profiling is achieved;

when the height of the header from the ground is greater than the preset height, the second proportional electromagnetic directional valve is powered on, oil in a rodless cavity of the lifting oil cylinder flows back to the oil tank through the second proportional electromagnetic directional valve and the second pressure compensation valve, the lifting oil cylinder descends under the action of the weight of the header, at the moment, the oil required by the rodless cavity of the lifting oil cylinder is pumped by the hydraulic pump and supplemented back through the electric proportional pressure reduction overflow valve, and the header descends continuously; when the header peripheral sensors detect that the header descends to the preset height, the second proportional electromagnetic directional valve is powered off, oil in the rodless cavity of the lifting oil cylinder is in a pressure maintaining state under the action of the one-way valve and the second proportional electromagnetic directional valve, so that the header is stabilized at the preset height, and the purpose of active profiling is achieved.

10. A hydraulic control method for profiling a header in agricultural harvesting equipment is characterized by comprising the following steps: the specific process of header passive profiling using the hydraulic control system of claim 8 is as follows:

in the passive profiling process of the header, the first proportional electromagnetic directional valve and the second proportional electromagnetic directional valve lose power, the electromagnetic valve is powered on and opened, so that a rod cavity and a rodless cavity of the lifting oil cylinder are in differential connection, the hydraulic pump pumps oil and enters the rodless cavity of the lifting oil cylinder through the electric proportional pressure reducing overflow valve, and under the action of the weight of the header, the lifting oil cylinder does not extend out and simultaneously provides stable supporting force for the header, so that the force of the weight of the header on the profiling wheel is reduced; meanwhile, after the header height and the harvesting effect are processed and analyzed by the vehicle data processing system, the output current of the electric proportional pressure reducing overflow valve is adjusted to change the pressure of the lifting oil cylinder, so that the auxiliary supporting force of the lifting oil cylinder to the header is adjusted, and the header can achieve the optimal profiling effect under various terrains;

in the cutting and advancing process of the cutting table, the profiling wheel pushes the cutting table to move up and down according to the fluctuation of the ground, in the upward moving process of the cutting table, the lifting oil cylinder is driven to extend out, the oil pressure in the lifting oil cylinder is reduced, the hydraulic pump pumps oil, and the oil is supplemented into the lifting oil cylinder through the electric proportional pressure reducing overflow valve, so that the pressure in the lifting oil cylinder is stabilized at a set value;

in the downward movement process of the cutting table, the compression lifting oil cylinder descends, the oil pressure in the lifting oil cylinder is increased, and part of oil in the lifting oil cylinder overflows from the electric proportional pressure reducing overflow valve and flows back to the oil tank, so that the pressure in the lifting oil cylinder is stabilized at a set value, and the purpose of passive profiling is achieved.

Technical Field

The invention relates to the technical field of agricultural machinery, in particular to a hydraulic control system for profiling a header in agricultural harvesting equipment and a control method thereof.

Background

With the development of modern agriculture, the step of agricultural mechanization is faster and faster, and various crop harvesting machines are more and more. In current agricultural harvesting machine, the header is provided with carousel formula and picks up two kinds of types, wherein: the turntable type header is mainly used for harvesting crops in an immature period, and harvested straws are used as silage; the pickup header is mainly used for harvesting mature crops, and can cut stalks into yellow silage while collecting the crops.

When the turntable type header is used, the height between the header and the ground is detected through sensors around the header, and the height is fed back to a header control system to adjust the header height so as to achieve the purpose of profiling; when the pickup type cutting table is used, the height of the cutting table is adjusted through the fluctuation of the profiling wheel below the cutting table, so that the profiling purpose is achieved. At present, because two kinds of header control methods are different, so need different machinery to control to it leads to it to have following not enough: 1) the hydraulic control system for header profiling has a single control mode, the same control system cannot be suitable for controlling headers of different specifications and different weights, headers of different specifications cannot be interchanged, and the universality is poor; 2) when the cutting table is passively profiled, the auxiliary supporting oil cylinder cannot adjust the stress on the profiling wheel according to the weight of the cutting table, when the weight of the cutting table is larger, the stress of the profiling wheel is larger, and the profiling effect is poor.

Disclosure of Invention

The invention aims to provide a hydraulic control system for profiling a header in agricultural harvesting equipment and a control method thereof, aiming at overcoming the defects in the prior art.

In order to achieve the aim, the invention provides a hydraulic control system for profiling a cutting table in agricultural harvesting equipment, which comprises a hydraulic pump, an oil tank, an oil supply oil way, a lifting oil cylinder, an oil return oil way and a thrust adjusting oil way, wherein the hydraulic pump is connected with the oil tank; the lifting oil cylinder is used for controlling the header to ascend or descend and comprises a rod cavity and a rodless cavity, a connecting oil way is arranged between the rod cavity and the rodless cavity, and a switch valve is arranged on the connecting oil way; the oil supply circuit is used for connecting the hydraulic pump and the rodless cavity of the lifting oil cylinder, a first flow control mechanism and a one-way valve are arranged on the oil supply circuit, and oil is pumped by the hydraulic pump and is conveyed into the rodless cavity of the lifting oil cylinder through the first flow control mechanism and the one-way valve; the oil return circuit is used for connecting the oil tank and a rod chamber of the lifting oil cylinder, a second flow control mechanism is arranged on the oil return circuit, and oil flows back into the oil tank through the second flow control mechanism; the thrust adjusting oil way is connected with the lifting oil cylinder, the hydraulic pump and the oil tank, and a pressure reducing overflow piece is arranged on the thrust adjusting oil way.

Preferably, the oil supply oil path, the oil return oil path and the thrust adjusting oil path are connected with the communicating oil path.

Preferably, the first flow control mechanism and the second flow control mechanism are both provided as proportional electromagnetic directional valves with compensators.

Preferably, the first flow control mechanism and the second flow control mechanism are both provided as a combined structure of a proportional electromagnetic directional valve and a pressure compensation valve.

Preferably, the switching valve is provided as a solenoid valve or a manual valve.

Preferably, the pressure reduction overflow member is a combined structure of a pressure reduction valve and an overflow valve, and is preferably an electric proportional pressure reduction overflow valve.

As a further aspect of the present invention, the hydraulic control system further includes a pressure sensor for detecting the hydraulic pressure in the lift cylinder.

As a further scheme of the invention, the specific process of performing header active profiling by applying the hydraulic control system is as follows:

when the height of the header from the ground is smaller than the preset height, a first proportional electromagnetic directional valve and a hydraulic pump are started, the hydraulic pump pumps oil, the oil sequentially enters a rodless cavity of a lifting oil cylinder through the first proportional electromagnetic directional valve, a first pressure compensation valve and a one-way valve, the lifting oil cylinder lifts, and meanwhile, the oil in a rod cavity of the lifting oil cylinder flows back to an oil tank through an electric proportional pressure reduction overflow valve; when the sensors around the header detect that the header rises to the preset height, the first proportional electromagnetic directional valve loses electricity, and meanwhile, oil in the rodless cavity of the lifting oil cylinder is in a pressure maintaining state under the action of the one-way valve, so that the header is stabilized at the preset height, and the purpose of profiling is achieved;

when the height of the header from the ground is greater than the preset height, the second proportional electromagnetic directional valve is powered on, oil in a rodless cavity of the lifting oil cylinder flows back to the oil tank through the second proportional electromagnetic directional valve and the second pressure compensation valve, the lifting oil cylinder descends under the action of the weight of the header, at the moment, the oil required by the rodless cavity of the lifting oil cylinder is pumped by the hydraulic pump and supplemented back through the electric proportional pressure reduction overflow valve, and the header descends continuously; when the header peripheral sensors detect that the header descends to the preset height, the second proportional electromagnetic directional valve is powered off, oil in the rodless cavity of the lifting oil cylinder is in a pressure maintaining state under the action of the one-way valve and the second proportional electromagnetic directional valve, so that the header is stabilized at the preset height, and the purpose of active profiling is achieved.

As a further scheme of the invention, the specific process of passive profiling of the header by applying the hydraulic control system is as follows:

in the passive profiling process of the header, the first proportional electromagnetic directional valve and the second proportional electromagnetic directional valve lose power, the electromagnetic valve is powered on and opened, so that a rod cavity and a rodless cavity of the lifting oil cylinder are in differential connection, the hydraulic pump pumps oil and enters the rodless cavity of the lifting oil cylinder through the electric proportional pressure reducing overflow valve, and under the action of the weight of the header, the lifting oil cylinder does not extend out and simultaneously provides stable supporting force for the header, so that the force of the weight of the header on the profiling wheel is reduced; meanwhile, after the header height and the harvesting effect are processed and analyzed by the vehicle data processing system, the output current of the electric proportional pressure reducing overflow valve is adjusted to change the pressure of the lifting oil cylinder, so that the auxiliary supporting force of the lifting oil cylinder to the header is adjusted, and the header can achieve the optimal profiling effect under various terrains;

in the cutting and advancing process of the cutting table, the profiling wheel pushes the cutting table to move up and down according to the fluctuation of the ground, in the upward moving process of the cutting table, the lifting oil cylinder is driven to extend out, the oil pressure in the lifting oil cylinder is reduced, the hydraulic pump pumps oil, and the oil is supplemented into the lifting oil cylinder through the electric proportional pressure reducing overflow valve, so that the pressure in the lifting oil cylinder is stabilized at a set value;

in the downward movement process of the cutting table, the compression lifting oil cylinder descends, the oil pressure in the lifting oil cylinder is increased, and part of oil in the lifting oil cylinder overflows from the electric proportional pressure reducing overflow valve and flows back to the oil tank, so that the pressure in the lifting oil cylinder is stabilized at a set value, and the purpose of passive profiling is achieved.

The working principle of the invention is as follows:

during active profiling, according to the height between the header and the ground detected by sensors around the header, the first proportional electromagnetic directional valve or the second proportional electromagnetic directional valve is controlled to be opened or closed to feed or return oil to the rodless cavity of the lifting oil cylinder, so that the header is adjusted to be lifted in real time, the header is kept at a fixed height from the ground, and the purpose of profiling is achieved;

during passive profiling, the electromagnetic valve is opened to enable the rod chamber and the rodless chamber of the lifting oil cylinder to form differential connection, oil is pumped by the hydraulic pump and is supplied to the lifting oil cylinder through the electric proportional pressure reducing overflow valve, so that the lifting oil cylinder does not extend to provide a stable supporting force for the header under the action of the self weight of the header, the magnitude of the output current of the electric proportional pressure reducing overflow valve can be adjusted according to different terrains, geology and harvested crops, the magnitude of the supporting force of the lifting oil cylinder on the header is changed, the force of the header weight on the profiling wheel is reduced, and the optimal profiling effect of the header in the profiling process is achieved. A pressure sensor is added in the rodless cavity of the oil cylinder, and the current of the electric proportional pressure reducing overflow valve can be adjusted in real time through the pressure feedback of the pressure sensor, so that closed-loop control is formed, and the accurate adjustment of the supporting force of the oil cylinder is further realized; the effects of proportional valve hysteresis or manufacturing variability that may occur in open loop control are avoided.

Compared with the prior art, the invention has the following beneficial effects:

(1) the hydraulic control system provided by the invention can implement active profiling control of the header through mutual matching of the hydraulic pump, the oil tank, the oil supply circuit, the lifting oil cylinder and the oil return circuit, and can also implement passive profiling control of the header by forming differential connection between the rod cavity and the rodless cavity of the lifting oil cylinder through controlling the connecting oil circuit, thereby improving the operation flexibility of the system and reducing the production cost and economic burden of farmers when harvesting different crops.

(2) The invention adopts the differential connection of the rod chamber and the rodless chamber of the lifting oil cylinder by adopting the electromagnetic valve during passive profiling, so that the telescopic speed of the lifting oil cylinder is faster, and the dynamic change time of the lifting oil cylinder is reduced, thereby realizing that the hydraulic control system is suitable for working under the condition of complex terrain.

(3) According to the invention, by arranging the pressure compensation valve, when the hydraulic control system controls the header to perform active profiling, the flow of oil entering the lifting oil cylinder is not influenced by load change under the action of the pressure compensation valve, so that the stability of the header in the lifting/descending process is ensured.

(4) According to the invention, the electric proportional pressure reducing overflow valve is arranged, so that when the header is passively profiled, the header is pushed to move up and down by the profiling wheel according to the fluctuation of the ground, and the pressure in the oil cylinder is increased or reduced, the oil in the lifting oil cylinder is supplemented or overflowed by the electric proportional pressure reducing overflow valve, so that the pressure in the lifting oil cylinder is kept at a set value, the auxiliary supporting force of the lifting oil cylinder on the header cannot be influenced by the change of the height of the header, and the problem that the profiling effect of the profiling wheel is poor due to the overlarge weight of the header is solved.

(5) According to the invention, the proportional electromagnetic directional valve is arranged to control the flow rate of oil entering/flowing out of the lifting oil cylinder, so that the lifting oil cylinder speed during lifting/descending is controlled, and the stability of the cutting table during lifting/descending is ensured.

(6) According to the invention, by arranging the electric proportional pressure reducing overflow valve, when passive profiling is carried out, the output current can be remotely adjusted according to the profiling effect, so that the pressure of the lifting oil cylinder is changed, the profiling under different complex terrain working conditions is adapted, the best matching of the forces of the cutting table acting on the profiling wheel under different terrains is achieved, and the electric proportional pressure reducing overflow valve has the advantages of simplicity in operation, multiple adaptive working conditions, high intelligent degree and the like.

In addition to the objects, features and advantages described above, other objects, features and advantages of the present invention are also provided. The present invention will be described in further detail below with reference to the drawings.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of this application, illustrate embodiments of the invention and, together with the description, serve to explain the invention and not to limit the invention. In the drawings:

fig. 1 is a schematic structural connection diagram of a hydraulic control system in an embodiment of the invention.

Wherein:

1. the device comprises a first proportional electromagnetic directional valve, a second proportional electromagnetic directional valve, a first pressure compensation valve, a check valve, a second pressure compensation valve, a first proportional electromagnetic directional valve, a second proportional electromagnetic directional valve, a first electromagnetic valve, a second pressure compensation valve, a second electromagnetic directional valve, a second electromagnetic directional valve, a second electromagnetic valve, a lifting oil, a second electromagnetic valve, a lifting oil, a second lifting oil, a pressure sensor, a second lifting oil, a pressure sensor, a second lifting oil, a pressure sensor, a second lifting oil, a.

Detailed Description

In order to make the aforementioned objects, features, advantages, and the like of the present invention more clearly understandable, embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be noted that the drawings of the present invention are simplified and are not to precise scale, and are provided for convenience and clarity in assisting the description of the embodiments of the present invention; the several references in this disclosure are not limited to the particular numbers in the examples of the figures; the directions or positional relationships indicated by ' front ' middle, ' rear ' left ', right ', upper ', lower ', top ', bottom ', middle ', etc. in the present invention are based on the directions or positional relationships shown in the drawings of the present invention, and do not indicate or imply that the devices or components referred to must have a specific direction, nor should be construed as limiting the present invention.

Example (b):

referring to fig. 1, the hydraulic control system for profiling a header in agricultural harvesting equipment provided by the invention comprises a hydraulic pump, an oil tank, an oil supply circuit, a lifting oil cylinder 8, an oil return circuit and a thrust adjusting oil circuit; the lifting oil cylinder 8 comprises a rod chamber and a rodless chamber, the rod chamber and the rodless chamber are connected through a connecting oil way, and the connecting oil way is provided with an electromagnetic valve 6 for controlling the connection or disconnection between the rod chamber and the rodless chamber; the oil supply circuit is used for connecting the lifting oil cylinder 8 and a hydraulic pump, and is sequentially provided with a first proportional electromagnetic valve 1, a first pressure compensation valve 2 and a one-way valve 3 along the flowing direction of oil, and the oil is pumped by the hydraulic pump and is conveyed into a rodless cavity of the lifting oil cylinder 8 through the first proportional electromagnetic valve 1, the first pressure compensation valve 2 and the one-way valve 3 so as to supply oil to the lifting oil cylinder 8; the oil return circuit is used for connecting the lifting oil cylinder 8 and the oil tank, the oil return circuit is sequentially provided with a second pressure compensation valve 4 and a second proportional electromagnetic directional valve 5 along the oil flowing direction, and oil in the rod cavity of the lifting oil cylinder 8 flows back into the oil tank through the second pressure compensation valve 4 and the second proportional electromagnetic directional valve 5 so as to realize the recovery of the oil; the thrust adjusting oil way is used for connecting the lifting oil cylinder 8 with a hydraulic pump or connecting the lifting oil cylinder 8 with an oil tank, and an electric proportional pressure reducing overflow valve 7 is arranged on the thrust adjusting oil way.

Preferably, in order to monitor the hydraulic pressure in the lifting cylinder 8 in real time, the hydraulic control system further comprises a pressure sensor 9, and the pressure sensor 9 is connected with the lifting cylinder 8.

Preferably, the control method for the header active profiling by using the hydraulic control system comprises the following specific working processes:

when the height of the cutting platform from the ground is smaller than a preset height (the height of the cutting platform from the ground is detected by a sensor arranged on the periphery of the cutting platform, detected data are transmitted to a control system of the cutting platform and are compared with the preset height in the control system of the cutting platform), a first proportional electromagnetic directional valve 1 and a hydraulic pump are started, the hydraulic pump pumps oil, the oil sequentially enters a rodless chamber of a lifting oil cylinder 8 through the first proportional electromagnetic directional valve 1, a first pressure compensation valve 2 and a one-way valve 3, the lifting oil cylinder 8 lifts, and meanwhile, the oil in a rod chamber of the lifting oil cylinder 8 flows back to an oil tank through an electric proportional pressure reduction overflow valve 7;

when the sensors around the header detect that the header rises to the preset height, the first proportional electromagnetic directional valve 1 is powered off, and meanwhile, oil in the rodless cavity of the lifting oil cylinder 8 is in a pressure maintaining state under the action of the one-way valve 3, so that the header is stabilized at the preset height;

when the height of the header from the ground is larger than the preset height, the second proportional electromagnetic directional valve 5 is electrified, oil in a rodless cavity of the lifting oil cylinder 8 flows back to an oil tank through the second proportional electromagnetic directional valve 5 and the second pressure compensation valve 4, the lifting oil cylinder 8 descends under the action of the weight of the header, at the moment, the oil required by the rodless cavity of the lifting oil cylinder 8 is pumped by the hydraulic pump and is supplemented through the electric proportional pressure reduction overflow valve 7, and the header descends continuously;

when the sensors around the header detect that the header descends to a preset height, the second proportional electromagnetic directional valve 5 is powered off, oil in the rodless cavity of the lifting oil cylinder 8 is in a pressure maintaining state under the action of the one-way valve 3 and the second proportional electromagnetic directional valve 5, and the header is stabilized at the preset height;

in the harvesting process of the header, the position of the header can be adjusted up and down according to the distance between the header and the ground, which is detected by the sensor, so that the header is kept at a fixed height with the ground, and the purpose of profiling is achieved.

Preferably, the control method for the header passive profiling by using the hydraulic control system comprises the following specific working processes:

in the passive profiling process of the header, the first proportional electromagnetic directional valve 1 and the second proportional electromagnetic directional valve 5 lose power, the electromagnetic valve 6 is powered on and opened, so that a rod cavity and a rodless cavity of the lifting oil cylinder 8 are in differential connection, the hydraulic pump pumps oil and enters the rodless cavity of the lifting oil cylinder 8 through the electric proportional pressure reducing overflow valve 7, under the action of the weight of the header, the lifting oil cylinder 8 does not extend out, meanwhile, a stable supporting force is provided for the header, and the force of the weight of the header on the profiling wheel is reduced; meanwhile, after the height and the harvesting effect of the header are processed and analyzed according to a vehicle data processing system (a sensor on a vehicle monitors the height and the harvesting effect of the header in real time and performs data processing and analysis on the height and the harvesting effect of the header), the output current of the electric proportional pressure reducing overflow valve is adjusted to change the pressure of the lifting oil cylinder, so that the auxiliary supporting force of the lifting oil cylinder on the header is adjusted, the header can achieve the best profiling effect under various terrains, the output current of the electric proportional pressure reducing overflow valve can also be manually adjusted, the pressure of the oil cylinder is observed through a pressure sensor 9 of the lifting oil cylinder, and the purpose of manually changing the auxiliary supporting force is achieved;

in the cutting table harvesting advancing process, the profiling wheel pushes the cutting table to move up and down according to the fluctuation of the ground, in the cutting table moving up process, the lifting oil cylinder 8 is driven to extend out, the oil pressure in the lifting oil cylinder 8 is reduced, the hydraulic pump pumps oil, the oil is supplemented into the lifting oil cylinder 8 through the electric proportional pressure reducing overflow valve 7, and the pressure in the lifting oil cylinder 8 is stabilized at a set value;

in the downward movement process of the header, the compression lifting oil cylinder 8 descends, the oil pressure in the lifting oil cylinder 8 is increased, oil in the lifting oil cylinder 8 overflows a part from the electric proportional pressure reducing overflow valve 7 and flows back to the oil tank, and the pressure in the lifting oil cylinder 8 is stabilized at a set value (therefore, no matter how the header moves up and down according to the terrain, the hydraulic oil pressure in the lifting oil cylinder 8 keeps unchanged, namely the auxiliary supporting force of the lifting oil cylinder 8 on the header keeps unchanged, the auxiliary supporting force of the oil cylinder on the header cannot be influenced by the change of the height of the header, the stress on the profiling wheel always keeps unchanged, and the passive profiling effect of the header is better).

The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.