A baler and its bale density adjustment and control hydraulic system

Abstract

The invention discloses a baler and a hydraulic system for adjusting and controlling the density of straw bales, comprising a hydraulic cylinder, an oil return tank, a hydraulic pump, a rodless electromagnetic reversing valve, a pressure-boosting electromagnetic reversing valve, a pressure-reducing electromagnetic reversing valve and a pressure sensor; the oil inlet of the hydraulic pump is connected to the oil supply port of the oil return tank; the rod chamber of the hydraulic cylinder is connected to the first oil port of the pressure-reducing electromagnetic reversing valve, and the second oil port of the pressure-reducing electromagnetic reversing valve is connected to the first oil port of the pressure-boosting electromagnetic reversing valve; the second oil port of the pressure-boosting electromagnetic reversing valve is connected to the oil outlet of the hydraulic pump, and the third oil port of the pressure-boosting electromagnetic reversing valve is connected to the oil return port of the oil return tank; the rodless chamber of the hydraulic cylinder is connected to the first oil port of the rodless electromagnetic reversing valve, the second oil port of the rodless electromagnetic reversing valve is connected to the oil outlet of the hydraulic pump, and the third oil port of the rodless electromagnetic reversing valve is connected to the oil return port of the oil return tank. By using the baler and the hydraulic system for adjusting and controlling the density of straw bales, stepless regulation of the straw bale pressing mechanism can be realized with high control accuracy.

Description

Technical Field

[0001] The present invention relates to the technical field of agricultural machinery, and more specifically, to a bale density adjustment and control hydraulic system of a baler, and also to a baler. Background Art

[0002] Square bale baler is an agricultural equipment suitable for picking up, harvesting and baling crop straw. It has a wide range of applications and can pick up and bale straw and natural forage grass such as rice straw, wheat straw, cotton stalks, corn stalks, rape stalks, peanut vines, bean stalks, alfalfa, flax, etc. It has many supporting functions and high work efficiency. It is an indispensable harvesting machinery in agricultural production and a large-scale agricultural machinery equipment urgently needed in my country. The baler can not only solve the problem of severe labor shortage in the harvest season of agricultural production, but also save labor costs and greatly improve work efficiency.

[0003] The last link of the baler is to control the density of the bale in the density control room at the end of the square baler. At present, the general operation mode of this link is to adjust the stroke range of the double-acting hydraulic drive push rods on both sides of the control room, further adjust the inclination of the pressure beam, so that the cross section of the control room is gradually reduced, the volume of the bale is compressed, and the density of the bale is directionally controlled.

[0004] At present, the market demand for balers in China is increasing day by day, and the requirements for their performance are also getting higher and higher. Due to different requirements of users for the density of straw bales, the use of balers in different regions of my country is also different. For the current baler straw density control hydraulic system, most of them have complex structures, and their density adjustment system has a small adjustment range. The adaptability to different regions and different types of straw is also small, which limits the further promotion and application of balers. Moreover, most of the current baler straw density control systems are mechanical structure control methods, which require manual adjustment of straw density, with low adjustment accuracy, small straw density and poor safety. For some straw density control systems that use hydraulic methods, there is usually only one working mode of manual adjustment, which has poor adaptability. The straw density cannot be adjusted in real time in a closed loop according to different crops and different straw humidity, and the accuracy does not meet the requirements.

[0005] In summary, how to effectively solve the problems of small bale density adjustment range and low precision of balers is a problem that technical personnel in this field need to solve. Summary of the invention

[0006] In view of this, the first object of the present invention is to provide a bale density adjustment and control hydraulic system for a baler. The structural design of the bale density adjustment and control hydraulic system can effectively solve the problems of small bale density adjustment range and low precision of the baler. The second object of the present invention is to provide a baler including the above-mentioned bale density adjustment and control hydraulic system.

[0007] In order to achieve the above first object, the present invention provides the following technical solutions:

[0008] A bale density adjustment and control hydraulic system for a baler, comprising a hydraulic cylinder, an oil return tank, a hydraulic pump, a rodless electromagnetic reversing valve, a boost electromagnetic reversing valve, a pressure reducing electromagnetic reversing valve and a pressure sensor for detecting the rod chamber pressure of the hydraulic cylinder, wherein the piston rod of the hydraulic cylinder is used to push the bale;

[0009] The oil inlet of the hydraulic pump is connected to the oil supply port of the oil return tank;

[0010] The rod chamber of the hydraulic oil cylinder is connected to the first oil port of the pressure-reducing electromagnetic reversing valve, the second oil port of the pressure-reducing electromagnetic reversing valve is connected to the first oil port of the pressure-increasing electromagnetic reversing valve, and the pressure-reducing electromagnetic reversing valve is used to connect or cut off its first oil port and second oil port;

[0011] The second oil port of the boost solenoid reversing valve is connected to the oil outlet of the hydraulic pump, the third oil port of the boost solenoid reversing valve is connected to the return oil port of the oil return tank, and the boost solenoid reversing valve is used to switch its first oil port to communicate with its second oil port or third oil port;

[0012] The rodless chamber of the hydraulic cylinder is connected to the first oil port of the rodless solenoid reversing valve, the second oil port of the rodless solenoid reversing valve is connected to the oil outlet of the hydraulic pump, the third oil port of the rodless solenoid reversing valve is connected to the return oil port of the return oil tank, and the rodless solenoid reversing valve is used to switch its first oil port to connect with its second oil port or third oil port.

[0013] Preferably, in the above-mentioned bale density adjustment and control hydraulic system, the pressure-reducing electromagnetic reversing valve is a proportional electromagnetic reversing valve.

[0014] Preferably, the above-mentioned bale density adjustment and control hydraulic system further includes a pressure relief valve connected between the oil return port of the oil return tank and the rod chamber for controlling the opening and closing of the pipeline.

[0015] Preferably, in the above-mentioned bale density adjustment and control hydraulic system, a first damper and / or accumulator is provided in series with the pressure relief valve between the oil return port of the oil return tank and the rod chamber.

[0016] Preferably, in the above-mentioned bale density adjustment and control hydraulic system, the pressure-reducing solenoid reversing valve is a reversing valve that can be manually controlled and has a third oil port connected to the return oil port of the return oil tank, and the pressure-reducing solenoid reversing valve is used to switch its first oil port to be connected to its second oil port or third oil port.

[0017] Preferably, the above-mentioned bale density adjustment and control hydraulic system also includes an unloading electromagnetic reversing valve, the first oil port of the unloading electromagnetic reversing valve is connected to the oil outlet of the hydraulic pump, the second oil port of the unloading electromagnetic reversing valve is connected to the return oil port of the return oil tank, and the unloading electromagnetic reversing valve is used to connect or cut off its first oil port and the second oil port.

[0018] Preferably, the above-mentioned bale density adjustment and control hydraulic system further includes a second damper connected between the rod chamber and the pressure-reducing electromagnetic reversing valve.

[0019] Preferably, the above-mentioned bale density adjustment and control hydraulic system further includes an overflow valve connected between the oil outlet of the hydraulic pump and the oil return port of the oil return tank.

[0020] Preferably, the above-mentioned bale density adjustment and control hydraulic system further includes a filter connected to the oil outlet of the hydraulic pump.

[0021] The bale density adjustment and control hydraulic system of the baler provided by the present invention comprises a hydraulic cylinder, an oil return tank, a hydraulic pump, a rodless electromagnetic reversing valve, a boost electromagnetic reversing valve, a pressure reducing electromagnetic reversing valve and a pressure sensor for detecting the rod chamber pressure of the hydraulic cylinder. Among them, the piston rod of the hydraulic cylinder is used to push the bale; the oil inlet of the hydraulic pump is connected to the oil supply port of the return oil tank; the rod chamber of the hydraulic cylinder is connected to the first oil port of the pressure-reducing electromagnetic reversing valve, the second oil port of the pressure-reducing electromagnetic reversing valve is connected to the first oil port of the pressure-boosting electromagnetic reversing valve, and the pressure-reducing electromagnetic reversing valve is used to connect or cut off its first oil port and the second oil port; the second oil port of the pressure-boosting electromagnetic reversing valve is connected to the oil outlet of the hydraulic pump, the third oil port of the pressure-boosting electromagnetic reversing valve is connected to the return oil port of the return oil tank, and the pressure-boosting electromagnetic reversing valve is used to switch its first oil port to be connected to its second oil port or the third oil port; the rodless chamber of the hydraulic cylinder is connected to the first oil port of the rodless electromagnetic reversing valve, the second oil port of the rodless electromagnetic reversing valve is connected to the oil outlet of the hydraulic pump, the third oil port of the rodless electromagnetic reversing valve is connected to the return oil port of the return oil tank, and the rodless electromagnetic reversing valve is used to switch its first oil port to be connected to its second oil port or the third oil port.

[0022] The bale density adjustment and control hydraulic system of the baler provided by the present invention is applied. Before the formal baling work, the target value of the baling chamber piston load detection is first set according to the crop demand. When the grass pieces enter the baling chamber one after another and the detection value of the baling chamber piston load is less than the target value, the boost solenoid reversing valve is controlled to switch to the first oil port and the second oil port to be connected. At the same time, the first oil port and the second oil port of the pressure reduction solenoid control valve are connected, and the first oil port and the third oil port of the rodless solenoid reversing valve are connected. Then, the pressure oil passes through and enters the rod chamber of the hydraulic cylinder. The oil in the rodless chamber of the hydraulic cylinder flows back to the return oil tank through the rodless solenoid reversing valve. The piston rod of the hydraulic cylinder retracts, and the cross-sectional area of ​​the baling chamber outlet gradually decreases. At this time, the load value detected by the pressure sensor on the baling chamber piston and the pressure value detected by the rod chamber pressure sensor of the hydraulic cylinder gradually increase. When the load detected by the baling chamber piston reaches the target value, the boost solenoid reversing valve switches to the first oil port and the third oil port for communication, the first oil port and the second oil port of the pressure reducing solenoid reversing valve are disconnected, and the pressure oil in the rod chamber of the hydraulic cylinder is reversely locked by the pressure reducing solenoid reversing valve, so that the baling chamber always maintains a certain pressing force. At the same time, it is necessary to ensure that the pressure value detected by the pressure sensor of the rod chamber of the hydraulic cylinder is within a reasonable range to avoid overpressure, otherwise the target load value will be readjusted; when the detected load detected by the baling chamber piston is higher than the set target value, the first oil port and the second oil port of the baling chamber piston load are connected, and under the action of the bale tension, the oil in the rod chamber of the hydraulic cylinder flows to the return tank through the pressure reducing solenoid reversing valve, and the rodless chamber is replenished with oil through the rodless solenoid reversing valve. After the load of the baling chamber piston reaches the target value, the first oil port and the second oil port of the pressure reducing solenoid reversing valve are disconnected, and the pressure oil in the rod chamber of the hydraulic cylinder is reversely locked by the pressure reducing solenoid reversing valve.

[0023] In summary, the bale density adjustment and control hydraulic system provided in the present application is used to adjust the clamping force of the hydraulic cylinder in real time according to the target value of the baling chamber piston load set according to the density requirement, and the hydraulic pressure loaded by the hydraulic cylinder is detected in real time by the pressure sensor to avoid overpressure in the system. When a clamping force deviation occurs, it can be corrected and adjusted in real time by means of pressure increase and pressure reduction of the hydraulic system, thereby ensuring high precision of the clamping force control and uniform compaction degree of various parts of the bale. The bale clamping mechanism can be controlled steplessly, stably and reliably, and a closed-loop control is formed with high control precision and high bale density.

[0024] In order to achieve the above second object, the present invention further provides a baler, which includes any one of the above bale density adjustment and control hydraulic systems. Since the above bale density adjustment and control hydraulic system has the above technical effects, the baler having the bale density adjustment and control hydraulic system should also have corresponding technical effects. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0026] Figure 1 It is a schematic diagram of the principle of the bale chamber pressure-maintaining or system unloading working condition of the bale density adjustment and control hydraulic system of a specific embodiment of the present invention;

[0027] Figure 2 Schematic diagram of the working principle of the bale chamber pressurization of the hydraulic system for controlling the bale density;

[0028] Figure 3 Schematic diagram of the working principle of the pressure reduction in the baling chamber of the hydraulic system for controlling the density of the bale;

[0029] Figure 4 Schematic diagram of the active release working condition of the baling chamber of the hydraulic system for controlling the bale density.

[0030] The following are marked in the accompanying drawings:

[0031] Hydraulic pump 1, filter 2, unloading electromagnetic reversing valve 3, overflow valve 4, rodless electromagnetic reversing valve 5, boost electromagnetic reversing valve 6, pressure reduction electromagnetic reversing valve 7, second damping 8, accumulator 9, pressure sensor 10, hydraulic cylinder 11, pressure relief valve 12, first damping 13. DETAILED DESCRIPTION

[0032] The embodiment of the invention discloses a bale density adjustment control hydraulic system of a baler, so as to improve the bale density adjustment accuracy of the baler.

[0033] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0034] In a specific embodiment, the bale density adjustment and control hydraulic system of the baler provided by the present invention includes a hydraulic cylinder 11, an oil return tank, a hydraulic pump 1, a rodless solenoid reversing valve 5, a boost solenoid reversing valve 6, a pressure reduction solenoid reversing valve 7 and a pressure sensor 10.

[0035] The piston rod of the hydraulic cylinder 11 is used to push the bale. The number of the hydraulic cylinders 11 is not specifically limited here. In the case where the baler includes a plurality of hydraulic cylinders 11, the connection modes of the plurality of hydraulic cylinders 11 are the same.

[0036] The pressure sensor 10 is used to detect the pressure of the rod chamber of the hydraulic cylinder 11, that is, to avoid overpressure in the baling chamber by real-time monitoring the pressure of the rod chamber of the hydraulic cylinder 11.

[0037] The hydraulic pump 1 is the power source of the system and is used to provide pressure oil. The oil inlet of the hydraulic pump 1 is connected to the oil supply port of the return oil tank, that is, it is used to pump out the hydraulic oil in the return oil tank.

[0038] The working port A of the rod chamber of the hydraulic cylinder 11 is connected to the first oil port of the pressure-reducing electromagnetic reversing valve 7, and the second oil port of the pressure-reducing electromagnetic reversing valve 7 is connected to the first oil port of the pressure-increasing electromagnetic reversing valve 6. The pressure-reducing electromagnetic reversing valve 7 can connect or cut off its first oil port and the second oil port. In the following embodiments, the first oil port and the second oil port of the pressure-reducing electromagnetic reversing valve 7 are disconnected in the power-off state to achieve the pressure maintenance of the rod chamber of the hydraulic cylinder 11. When the pressure-reducing electromagnetic reversing valve 7 is powered on, the first oil port and the second oil port are connected as an example. The connection states corresponding to power on and power off can also be interchanged as needed, and the control strategy can be adjusted accordingly. Specifically, the pressure-reducing electromagnetic reversing valve 7 is a proportional electromagnetic reversing valve. Then, when the pressure-reducing electromagnetic reversing valve 7 is powered on, the first oil port and the second oil port are connected to control the return oil flow of the rod chamber of the hydraulic cylinder 11 and adjust the extension speed of the cylinder.

[0039] The second oil port of the boost solenoid reversing valve 6 is connected to the oil outlet of the hydraulic pump 1, and the third oil port of the boost solenoid reversing valve 6 is connected to the oil return port of the oil return tank. The boost solenoid reversing valve 6 can switch its first oil port to communicate with its second oil port or third oil port. That is, the boost solenoid reversing valve 6 is used to control the oil inlet and oil return of the rod chamber of the hydraulic cylinder 11. In the following embodiments, the boost solenoid reversing valve 6 is used as an example in the state of power on and in the state of power off. The connection states corresponding to the power on and power off can also be interchanged as needed, and the control strategy can be adjusted accordingly.

[0040] The working port B of the rodless chamber of the hydraulic cylinder 11 is connected to the first oil port of the rodless electromagnetic reversing valve 5, the second oil port of the rodless electromagnetic reversing valve 5 is connected to the oil outlet of the hydraulic pump 1, and the third oil port of the rodless electromagnetic reversing valve 5 is connected to the return oil port of the return oil tank. The rodless electromagnetic reversing valve 5 can switch its first oil port to be connected to its second oil port or the third oil port. That is, the rodless electromagnetic reversing valve 5 is used to control the oil inlet and return of the rodless chamber of the hydraulic cylinder 11. In the following embodiments, the rodless electromagnetic reversing valve 5 is used as an example in the energized state and the de-energized state. The connection states corresponding to the energized and de-energized states can also be interchanged as needed, and the control strategy can be adjusted accordingly.

[0041] The bale density adjustment and control hydraulic system of the baler provided by the present invention is applied. Before the formal baling work, the target value of the piston load detection of the baling chamber is first set according to the crop demand. When the grass pieces enter the baling chamber one after another and the detection value of the piston load of the baling chamber is less than the target value, refer to Figure 2 , the first oil port of the boost solenoid reversing valve 6 is energized to communicate with the second oil port, the pressure oil enters the rod chamber of the hydraulic cylinder 11, and the oil in the rodless chamber of the hydraulic cylinder 11 flows back to the return tank through the rodless solenoid reversing valve 5. The piston rod of the hydraulic cylinder 11 retracts, and the cross-sectional area of ​​the baling chamber outlet gradually decreases. At this time, the load value detected by the pressure sensor 10 on the baling chamber piston and the pressure value detected by the pressure sensor 10 in the rod chamber of the hydraulic cylinder 11 gradually increase.

[0042] When the bale chamber piston detection load reaches the target value, refer to Figure 1 , the boost solenoid reversing valve 6 is de-energized to connect the first oil port with the third oil port, the de-energized solenoid reversing valve 7 is de-energized to disconnect the first oil port with the second oil port, and the pressure oil in the rod chamber of the hydraulic cylinder 11 is reversely locked by the de-energized solenoid reversing valve 7, so that the baling chamber always maintains a certain pressing force. At the same time, it is necessary to ensure that the pressure value detected by the pressure sensor 10 in the rod chamber of the hydraulic cylinder 11 is within a reasonable range to avoid overpressure, otherwise the target load value will be readjusted.

[0043] When the detected load of the bale chamber piston is higher than the set target value, refer to Figure 3 , the first oil port of the pressure-reducing electromagnetic reversing valve 7 is energized and connected with the second oil port, the first oil port of the pressure-reducing electromagnetic reversing valve 6 is still de-energized and connected with the third oil port. Under the action of the bale tension, the oil in the rod chamber of the hydraulic cylinder 11 flows to the return oil tank through the pressure-reducing electromagnetic reversing valve 7, and the rodless chamber is replenished with oil through the rodless electromagnetic reversing valve 5. After the piston load in the baling chamber reaches the target value, the first oil port and the second oil port of the pressure-reducing electromagnetic reversing valve 7 are cut off, and the pressure oil in the rod chamber of the hydraulic cylinder 11 is reversely locked by the pressure-reducing electromagnetic reversing valve 7.

[0044] See also Figure 3 and Figure 4 When the baler completes the compaction of the last bale and needs to push it out, it is necessary to first relieve the pressure in the density cylinder and release the bale compression chamber. First, the pressure-reducing solenoid reversing valve 7 is energized and the first oil port is connected to the second oil port. Under the tension of the bale, the piston rod of the hydraulic cylinder 11 is passively pulled out, and the oil in the rod chamber flows back to the oil tank after passing through the pressure-reducing solenoid reversing valve 7. The rodless chamber of the hydraulic cylinder 11 is replenished with oil through the rodless solenoid reversing valve 5. When the rod chamber pressure sensor 10 detects that there is no pressure, the rodless solenoid reversing valve 5 and the pressure-reducing solenoid reversing valve 7 are energized at the same time, and the piston rod of the hydraulic cylinder 11 is actively extended. After the set time is reached, the bale compression chamber is completely released.

[0045] In summary, the bale density adjustment and control hydraulic system provided in the present application is used to adjust the clamping force of the hydraulic cylinder 11 in real time according to the target value of the baling chamber piston load set according to the density requirement, and the hydraulic pressure loaded by the hydraulic cylinder 11 is detected in real time by the pressure sensor 10 to avoid overpressure in the system. When a clamping force deviation occurs, it can be corrected and adjusted in real time by means of pressure increase and pressure reduction of the hydraulic system, thereby ensuring high precision of the clamping force control and uniform compaction degree of various parts of the bale. The bale clamping mechanism can be controlled steplessly, stably and reliably, and a closed-loop control is formed with high control precision and high bale density.

[0046] Furthermore, it also includes a pressure relief valve 12 connected between the return oil port of the return oil tank and the rod chamber for controlling the opening and closing of the pipeline. The pressure relief valve 12 can specifically be a ball valve. Through the provision of the pressure relief valve 12, the rod chamber of the hydraulic cylinder 11 can be manually depressurized in an emergency state. For example, if the baler suddenly encounters a mechanism jam failure or other emergency situations during operation, the baling chamber needs to be depressurized and repaired. Once the entire machine and the power supply of the entire machine cannot be started, the pressure in the rod chamber of the hydraulic cylinder 11 can be manually relieved and the ball valve can be opened. The pressure oil in the rod chamber of the hydraulic cylinder 11 flows back to the return oil tank through the ball valve to achieve the purpose of pressure relief. Specifically, a first damper 13 is provided in series with the pressure relief valve 12 between the return oil port of the return oil tank and the rod chamber. The first damper 13 can specifically be a damping hole. The function of the first damper 13 is to adjust the speed of the piston rod extension when the rod chamber of the hydraulic cylinder 11 is manually depressurized in an emergency state, that is, when the pressure oil in the rod chamber of the hydraulic cylinder 11 flows back to the return oil tank through the ball valve, that is, the first damper 13, to avoid causing a large impact on the hydraulic cylinder 11.

[0047] Furthermore, an accumulator 9 is provided in series with the pressure relief valve 12 between the oil return port of the oil return tank and the rod chamber. In the case of a damper, the accumulator 9 and the damper are also provided in series. The accumulator 9 provides a buffering effect on the rod chamber pressure of the hydraulic cylinder 11, adjusts the cylinder retraction speed, and reduces the hydraulic shock.

[0048] The pressure-reducing electromagnetic reversing valve 7 can be a pressure-reducing proportional electromagnetic reversing valve, or a two-position two-way electromagnetic reversing valve that can be manually controlled as needed. Then, the pressure relief valve 12 can be eliminated by setting the two-position two-way electromagnetic reversing valve. That is, the first oil port of the two-position two-way electromagnetic reversing valve is connected to the rod chamber of the hydraulic cylinder 11, the second oil port of the two-position two-way electromagnetic reversing valve is connected to the first oil port of the boosting electromagnetic reversing valve 6, and the third oil port of the two-position two-way electromagnetic reversing valve is connected to the return oil port of the return oil tank. The two-position two-way electromagnetic reversing valve is used to switch its first oil port to communicate with its second oil port or third oil port. When the baler suddenly encounters other emergency situations such as mechanism jamming failure during operation, the baling chamber needs to be depressurized and repaired. If the whole machine and the whole machine power supply cannot be started at this time, it is only necessary to manually control the reversal of the two-position two-way electromagnetic valve to connect the oil in the rod chamber of the cylinder back to the oil tank to achieve emergency pressure relief in the baling chamber.

[0049] In the above embodiments, the unloading electromagnetic reversing valve 3 is also included. The first oil port of the unloading electromagnetic reversing valve 3 is connected to the oil outlet of the hydraulic pump 1, and the second oil port of the unloading electromagnetic reversing valve 3 is connected to the return oil port of the return oil tank. The unloading electromagnetic reversing valve 3 can connect or cut off its first oil port and the second oil port. Specifically, when the unloading electromagnetic reversing valve 3 is powered, the first oil port and the second oil port are connected, and when the power is off, the first oil port and the second oil port are disconnected. Figure 1 As shown, when the system is not baling, the pressure sensor 10 installed on the baling chamber piston cannot detect the piston load, and the unloading electromagnetic reversing valve 3 is energized, and the system unloads through the unloading electromagnetic reversing valve 3. It can be seen that the unloading electromagnetic reversing valve 3 is used as a system unloading valve, which switches the system pressure through the detection feedback of the bale load, thereby reducing the power loss and heat generation of the system.

[0050] In the above embodiments, a second damper 8 is also included which is connected between the rod chamber and the pressure-reducing electromagnetic reversing valve 7. The function of the second damper 8 is to adjust the extension and retraction speed of the piston rod of the hydraulic cylinder 11, reduce the hydraulic shock under the pressure-increasing and pressure-reducing conditions of the hydraulic cylinder 11, and avoid damage to mechanical parts caused by a large hydraulic shock.

[0051] In the above embodiments, a relief valve 4 is also included which is connected between the oil outlet of the hydraulic pump 1 and the oil return port of the oil return tank. The relief valve 4 functions as a safety valve to limit the maximum pressure of the system.

[0052] In the above embodiments, a filter 2 connected to the oil outlet of the hydraulic pump 1 is also included. Specifically, the filter 2 is connected between the oil outlet of the hydraulic pump 1 and the second oil port of the rodless electromagnetic reversing valve 5, that is, all the components connected to the oil outlet of the hydraulic pump 1 are connected to the oil outlet of the hydraulic pump 1 through the filter 2. The filter 2 is set to filter impurities in the hydraulic system, ensure the cleanliness of the oil, and avoid the solenoid valve from getting stuck.

[0053] It should be noted that the above-mentioned solenoid reversing valves and other valves can be controlled automatically by the system or manually, that is, the system can work both automatically and manually, so it can adapt to a variety of working modes, is safe and reliable, and can meet a variety of straw baling operation requirements.

[0054] Specifically, after each baling work is completed, a bale is usually reserved in the baling chamber to avoid the tediousness of re-adjusting the density significantly during the next baling. Before the formal automatic baling work, the system can be switched to manual control mode, and the boost solenoid reversing valve 6 and the pressure reduction solenoid reversing valve 7 can be manually operated to gain power or lose power, so as to realize the pressure increase and pressure reduction of the density control cylinder, and to detect whether the entire bale density hydraulic control system is working normally through the change of pressure value.

[0055] In order to better illustrate the present solution, a preferred implementation is taken as an example below.

[0056] In this example, see Figure 1-Figure 4 The bale density adjustment and control hydraulic system includes a hydraulic pump 1, a filter 2, an unloading electromagnetic reversing valve 3, a relief valve 4, a rodless electromagnetic reversing valve 5, a boost electromagnetic reversing valve 6, a pressure reduction electromagnetic reversing valve 7, a second damper 8, an accumulator 9, a pressure sensor 10, a hydraulic cylinder 11, a pressure relief valve 12 and a first damper 13, wherein the pressure reduction electromagnetic reversing valve 7 is a proportional electromagnetic reversing valve.

[0057] See also Figure 1 When the system is not performing baling, the pressure sensor 10 installed on the baling chamber piston cannot detect the piston load, the unloading electromagnetic reversing valve 3 is energized, its first oil port is connected to the second oil port, and the system is unloaded through the unloading electromagnetic reversing valve 3.

[0058] See also Figure 2-Figure 4 Before the formal baling work, the target value of the baling chamber piston detection load is first set according to the crop demand. When the grass pieces enter the baling chamber one after another, the load detected by the baling chamber piston can be observed through the display screen. The system compares the detection value of the baling chamber piston load with the target value. The initial detection value is small. When the detection value is less than the target value, the system automatically controls the boost electromagnetic reversing valve 6 to be energized, and the pressure oil enters the rod chamber of the hydraulic cylinder 11 after buffering and speed regulation by the second damper 8 and the accumulator 9. The oil in the rodless chamber of the hydraulic cylinder 11 returns to the oil tank through the rodless electromagnetic reversing valve 5, and the piston rod of the hydraulic cylinder 11 slowly retracts, and the cross-sectional area of ​​the baling chamber outlet gradually decreases. At this time, the load value detected by the pressure sensor 10 on the baling chamber piston and the pressure value detected by the rod chamber pressure sensor 10 of the hydraulic cylinder 11 gradually increase.

[0059] After the piston load reaches the target value, the boost solenoid reversing valve 6 is powered off, and the pressure oil in the rod chamber of the hydraulic cylinder 11 is reversely locked by the depressurization solenoid reversing valve 7, so that the baling chamber always maintains a certain pressing force. At the same time, it is necessary to ensure that the pressure value detected by the rod chamber pressure sensor 10 of the hydraulic cylinder 11 is within a reasonable range to avoid overpressure, otherwise the target load value will be readjusted.

[0060] When the detected piston load value is higher than the set target value, the pressure-reducing electromagnetic reversing valve 7 is energized. Under the action of the bale tension, the oil in the rod chamber of the hydraulic cylinder 11 slowly flows back to the oil tank after passing through the second damping 8 and the pressure-reducing electromagnetic reversing valve 7 to adjust the speed, and the rodless chamber is replenished with oil through the rodless electromagnetic reversing valve 5. After the piston load reaches the target value, the pressure-reducing electromagnetic reversing valve 7 is de-energized, and the pressure oil in the rod chamber of the hydraulic cylinder 11 is reversely locked by the pressure-reducing electromagnetic reversing valve 7.

[0061] In summary, the bale density adjustment and control hydraulic system provided by the present invention is in an unloading state when the grass pressing piston cannot detect the load or detects that the bale density is within the set range, thereby reducing the power loss and heat generation of the hydraulic system of the whole machine; when the humidity of the baled crops and bales is different, the extension and retraction amount of the cylinder piston rod are adjusted in real time in a closed loop through multi-machine electro-hydraulic joint control to control the contraction cross-sectional area of ​​the baling chamber, thereby realizing automatic and precise control of the bale density; before officially entering the automatic working mode, the bale can be pressurized and reduced by manual control, and the change of the cylinder pressure value can be observed to confirm whether the bale density control hydraulic system is in a normal working state; before the baler completes the compression and pushes out the last bale, the compression device needs to be depressurized, firstly, the piston rod is passively extended by using the expansion characteristics of the bale, and when the bale is completely released, the baling chamber can be completely released by the active extension of the cylinder; in the emergency mode, the compression device can be depressurized and repaired through a manual valve.

[0062] In the above embodiments, the automatic control of density is achieved through the rodless electromagnetic reversing valve 5, the boost electromagnetic reversing valve 6, and the pressure-reducing electromagnetic reversing valve 7. In another embodiment, the rodless electromagnetic reversing valve 5, the boost electromagnetic reversing valve 6, and the pressure-reducing electromagnetic reversing valve 7 are eliminated, and an electric proportional regulating relief valve 4 is added to the outlet bypass passage of the hydraulic pump 1. The electric proportional regulating relief valve 4 current is adjusted in real time according to load feedback to change the relief pressure at the pump outlet, thereby changing the internal pressure of the rod chamber of the oil cylinder to achieve different density control of the bale.

[0063] Based on the bale density adjustment and control hydraulic system provided in the above embodiments, the present invention further provides a baler, which includes any one of the bale density adjustment and control hydraulic systems in the above embodiments. Since the baler adopts the bale density adjustment and control hydraulic system in the above embodiments, please refer to the above embodiments for the beneficial effects of the baler.

[0064] The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.

[0065] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A control method for a hydraulic system for controlling bale density of a baler, characterized in that: The bale density adjustment and control hydraulic system comprises a hydraulic cylinder (11), an oil return tank, a hydraulic pump (1), a rodless electromagnetic reversing valve (5), a boost electromagnetic reversing valve (6), a pressure reduction electromagnetic reversing valve (7), and a pressure sensor (10) for detecting the rod chamber pressure of the hydraulic cylinder (11); the piston rod of the hydraulic cylinder (11) is used to push the bale; The oil inlet of the hydraulic pump (1) is connected to the oil supply port of the oil return tank; The rod chamber of the hydraulic oil cylinder (11) is connected to the first oil port of the pressure-reducing electromagnetic reversing valve (7), the second oil port of the pressure-reducing electromagnetic reversing valve (7) is connected to the first oil port of the pressure-increasing electromagnetic reversing valve (6), and the pressure-reducing electromagnetic reversing valve (7) is used to connect or cut off its first oil port and second oil port; The second oil port of the boost solenoid reversing valve (6) is connected to the oil outlet of the hydraulic pump (1), the third oil port of the boost solenoid reversing valve (6) is connected to the oil return port of the oil return tank, and the boost solenoid reversing valve (6) is used to switch its first oil port to communicate with its second oil port or third oil port; The rodless chamber of the hydraulic oil cylinder (11) is connected to the first oil port of the rodless electromagnetic reversing valve (5), the second oil port of the rodless electromagnetic reversing valve (5) is connected to the oil outlet of the hydraulic pump (1), the third oil port of the rodless electromagnetic reversing valve (5) is connected to the oil return port of the oil return tank, and the rodless electromagnetic reversing valve (5) is used to switch its first oil port to communicate with its second oil port or third oil port; The method comprises: Before the formal baling operation, a target value for the detection load of the baling chamber piston is set, and the detection value of the baling chamber piston load is compared with the target value. When the detection value is less than the target value, the boosting electromagnetic reversing valve (6) is switched to connect the first oil port with the second oil port, and at the same time, the first oil port of the reducing electromagnetic reversing valve (7) is connected to the second oil port, and the first oil port of the rodless electromagnetic reversing valve (5) is connected to the third oil port, and the pressure oil enters the rod chamber of the hydraulic cylinder (11), and the oil in the rodless chamber of the hydraulic cylinder (11) flows to the return oil tank through the rodless electromagnetic reversing valve (5); After the detection value reaches the target value, the boost solenoid reversing valve (6) switches to connect the first oil port with the third oil port, the first oil port of the pressure reducing solenoid reversing valve (7) is disconnected from the second oil port, and the pressure oil in the rod chamber of the hydraulic cylinder (11) is reversely locked by the pressure reducing solenoid reversing valve (7); When the detected value of the piston load is higher than the target value, the first oil port of the pressure-reducing electromagnetic reversing valve (7) is connected to the second oil port. Under the action of the tension of the straw bale, the oil in the rod chamber of the hydraulic cylinder (11) flows back to the oil tank through the pressure-increasing electromagnetic reversing valve (6), and the rodless chamber is replenished with oil through the rodless electromagnetic reversing valve (5). When the detected value of the piston load reaches the target value, the first oil port of the pressure-reducing electromagnetic reversing valve (7) is disconnected from the second oil port, and the pressure oil in the rod chamber of the hydraulic cylinder (11) is reversely locked by the pressure-reducing electromagnetic reversing valve (7); The pressure-reducing electromagnetic reversing valve (7) is a reversing valve that can be manually controlled and has a third oil port connected to the oil return port of the oil return tank. The pressure-reducing electromagnetic reversing valve (7) is used to switch its first oil port to communicate with its second oil port or third oil port; After each baling operation is completed, a bale is reserved in the baling chamber. Before the automatic baling operation is officially started, the boosting electromagnetic reversing valve (6) and the reducing electromagnetic reversing valve (7) are manually operated to be energized or de-energized, and the pressure value change is used to detect whether the bale density hydraulic control system is operating normally.

2. The control method according to claim 1, characterized in that: The pressure-reducing electromagnetic reversing valve (7) is a proportional electromagnetic reversing valve.

3. The control method according to claim 2, characterized in that: It also includes a pressure relief valve (12) connected between the oil return port of the oil return tank and the rod chamber and used for controlling the opening and closing of the pipeline.

4. The control method according to claim 3, characterized in that: A first damper (13) and / or an accumulator (9) is arranged in series with the pressure relief valve (12) between the oil return port of the oil return tank and the rod chamber.

5. The control method according to any one of claims 1 to 4, characterized in that: It also comprises a unloading electromagnetic reversing valve (3), a first oil port of the unloading electromagnetic reversing valve (3) being connected to the oil outlet of the hydraulic pump (1), a second oil port of the unloading electromagnetic reversing valve (3) being connected to the oil return port of the oil return tank, and the unloading electromagnetic reversing valve (3) being used to connect or disconnect the first oil port and the second oil port thereof.

6. The control method according to any one of claims 1 to 4, characterized in that: It also includes a second damper (8) connected between the rod chamber and the pressure-reducing electromagnetic reversing valve (7).

7. The control method according to any one of claims 1 to 4, characterized in that: It also includes an overflow valve (4) connected between the oil outlet of the hydraulic pump (1) and the oil return port of the oil return tank.

8. The control method according to any one of claims 1 to 4, characterized in that: It also includes a filter (2) connected to the oil outlet of the hydraulic pump (1).

Images