A hydraulic control system and control method for complex machine actions

Abstract

This invention belongs to the technical field of greening maintenance equipment, specifically disclosing a hydraulic control system and method for composite machine movements. The hydraulic control system includes an electro-proportional control valve, an oil pump, an oil tank, and oil circuits. The oil tank is hydraulically connected to the electro-proportional control valve via the oil pump. One path of the electro-proportional control valve hydraulically controls a constant speed control valve group via the oil circuit. The constant speed control valve group hydraulically controls a drive motor A, which drives and connects to a machine. The other path of the electro-proportional control valve hydraulically controls a drive motor B via the oil circuit. The drive motor B drives and connects to a blade, which is fixed to the outer periphery of the bottom of the machine. This invention achieves the purpose of composite machine movements, meets the technical requirements of modern greening maintenance for composite operations, has low modification costs, a simple structure, a small workload and scope for modification, low construction difficulty, and high utilization efficiency of the modified parts, achieving the ideal design effect.

Description

Technical Field

[0001] This invention belongs to the technical field of greening maintenance equipment, specifically relating to a hydraulic control system and control method for composite machine actions. Background Technology

[0002] Green space maintenance equipment includes tools used for post-construction watering, pruning, weeding, spraying, and replanting of greenery. The comprehensive green space maintenance vehicle is one type of such equipment. Also known as a green space pruning vehicle, it is a specialized maintenance vehicle designed and manufactured for pruning median hedges, slopes, and greenery along first and second-class highways. It is primarily used for municipal greening and greenery pruning on highways. Traditional comprehensive green space maintenance vehicles typically have only one control hydraulic circuit at the end of the robotic arm, limiting their operation to single-action tasks and failing to meet the complex operational requirements of modern green space maintenance. To adapt to the technical requirements of modern greening maintenance for complex operations, the current method is to add a control valve group to the chassis, and then add an electronic control device and a control oil line from the chassis to the end of the robotic arm. This adds new valve groups and pipelines for the new control actions. This method has high modification costs, complex structure, and a large amount of work and scope of modification. It is also more difficult to construct for vehicles and equipment with limited installation space. Moreover, the space utilization efficiency after modification is low, making it extremely difficult to achieve the ideal effect.

[0003] Currently, hydraulic control systems have been implemented to enhance the operational complexity of integrated greening maintenance vehicles. For example, Chinese Patent Publication No. CN111552265A, published on August 18, 2020, discloses an automatic cross-regional mechanism, control system, and control method for an integrated greening maintenance vehicle. The document states that "the mechanism includes a sliding frame and a rotating frame mounted thereon. A rotating arm is mounted on the rotating frame, and the bottom of the rotating arm is connected to a tie rod assembly. A main working arm and a secondary working arm are connected to the rotating arm. A swing cylinder is provided on the rotating frame, and the swing cylinder is linked to the tie rod assembly." An angle sensing mechanism is installed on the rotating arm, and the control system of this automatic cross-area mechanism includes an electrical system and a hydraulic control device. This existing technology achieves cross-area operation for the integrated greening maintenance vehicle without changing its driving direction through two angle adjustment modes: manual micro-motion mode and automatic cross-area mode. While this increases the difficulty and efficiency of the integrated greening maintenance vehicle's work, the hydraulic control device in this existing technology operates according to the direction of the rotating frame and cannot control the complex movements of the machinery, thus failing to meet the technical requirements of modern greening maintenance for complex operations. Therefore, a new technical solution is needed to solve the above-mentioned technical problems. Summary of the Invention

[0004] The purpose of this invention is to provide a hydraulic control system and control method for complex machine movements, in order to solve the problems mentioned in the background art that the current hydraulic control system cannot meet the practical application requirements of complex machine movement control, and that the current control methods for complex machine movements are costly to modify, have complex structures, require a large amount of work and scope of modification, are difficult to construct, and are extremely difficult to achieve the desired effect.

[0005] To achieve the above objectives, the present invention provides the following technical solution: a hydraulic control system for compound actions of a machine tool, comprising an electro-proportional control valve, an oil pump, an oil tank, and an oil circuit. The oil tank is hydraulically connected to the electro-proportional control valve via the oil pump. One path of the electro-proportional control valve hydraulically controls a constant speed control valve group via the oil circuit. The constant speed control valve group hydraulically controls a drive motor A. The drive motor A drives and is connected to a machine tool. A boom is fixedly connected to the upper end of the machine tool. An oil circuit is mounted on the boom. The drive motor A is fixed to the end side of the machine tool. The constant speed control valve group is fixed to the edge of the machine tool. The other path of the electro-proportional control valve hydraulically controls a drive motor B via the oil circuit. The drive motor B is fixed to the center position of the machine tool. The drive motor B drives and is connected to a blade. The blade is fixed to the outer periphery of the bottom of the machine tool.

[0006] Furthermore, the constant speed control valve group includes a speed regulating valve and a pressure limiting valve. The input end of the speed regulating valve is connected to the output end of the electro-proportional control valve through an oil circuit. The output end of the speed regulating valve is divided into two paths: one path is connected to the input end of the pressure limiting valve, and the other path is connected to the input end of the drive motor A. The output ends of both the drive motor A and the pressure limiting valve are connected to the oil tank through an oil circuit.

[0007] Furthermore, the input end of the hydraulic motor B is connected to the output end of the electro-proportional control valve via an oil circuit, the input end of the electro-proportional control valve is connected to the oil tank via an oil pump, the electro-proportional control valve is also provided with a return oil port, the return oil port is directly connected to the oil tank, and the output end of the hydraulic motor B is connected to the oil tank via an oil circuit.

[0008] The hydraulic control system for combined machine actions, as described above, is used to control the combined operation of the machine and the blade. The specific steps of the control method are as follows:

[0009] S1. The hydraulic oil in the oil tank is pumped to the electro-proportional control valve, and then the electro-proportional control valve controls the total flow rate of the hydraulic oil output to 84-90L / min.

[0010] S2. The hydraulic oil input to the electro-proportional control valve is divided into two paths through the oil circuit and the three-way pipe joint and the output is controlled simultaneously: one path is controlled by the speed regulating valve and the pressure limiting valve to supply hydraulic oil with a flow rate of 4-6L / min to the drive motor A; the other path is the hydraulic oil with a flow rate of 80-84L / min after subtracting the hydraulic oil flow rate of hydraulic motor A from the total hydraulic oil flow rate of 84-90L / min, and is directly supplied to the drive motor B.

[0011] S3. Drive motor A, which obtains 4-6L / min of hydraulic oil, drives the machine to rotate under the control of speed control valve and pressure relief valve. The speed of the machine is 80r / min. Drive motor B, which obtains 80-84L / min of hydraulic oil, directly drives the blade to rotate. The speed of the blade is 2500r / min.

[0012] S4. When the blade or tool is rotating, both drive motor A and drive motor B return the hydraulic oil in their respective oil circuits to the oil tank. When the blade is overloaded, the electro-proportional control valve returns the hydraulic oil overflowing due to overpressure inside its internal oil tank through the return oil port.

[0013] Compared with the prior art, the beneficial effects of the present invention are:

[0014] 1. This invention utilizes the principle that the rotational speed of the constant-speed control valve group is independent of the load size, preventing the drive motor A from being damaged due to overpressure. This effectively improves the stability of the machine's rotational speed, thereby ensuring the reliability and safety of machine operation. By installing an oil circuit on the boom and fixing the drive motor B, the constant-speed control valve group, and the drive motor A at the center, edge, and side of the machine, the modification cost of the hydraulic control system is effectively reduced. This simplifies the structure of the boom hydraulic control system, effectively reduces the workload and scope of modification, saves installation space, reduces construction difficulty, and improves construction efficiency, thus ensuring that the hydraulic control system achieves the ideal design effect. The use of an electro-proportional control valve to control the hydraulic oil flow allows the hydraulic control system to not only drive the machine to rotate but also drive the blades to rotate synchronously at a constant speed. This enables the hydraulic control system to achieve the purpose of composite machine actions, meeting the technical requirements of modern greening maintenance for composite action operations.

[0015] 2. This invention utilizes the principle that the speed of the speed regulating valve is independent of the load size and only related to the valve opening size, so that when the drive motor A stops due to being blocked by an obstacle, the hydraulic oil is discharged in time through the pressure relief valve. This effectively avoids the problem of damage to the drive motor A due to overpressure, effectively improves the stability of the machine speed, and thus ensures the reliability and safety of machine operation.

[0016] 3. This invention uses an electro-proportional control valve to distribute hydraulic oil in the tank to drive motor A and drive motor B, so that the tool and blade can rotate simultaneously under the drive of drive motor A and drive motor B respectively. This enables the hydraulic control system to perform compound actions of the tool, meeting the technical requirements of modern greening maintenance for compound operations. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the overall structure of the present invention;

[0018] Figure 2 This is a circuit diagram of the hydraulic control system of the present invention (excluding the boom, tools and blades).

[0019] Figure 3 This is a top view of the machine structure of the present invention (including blades, electro-proportional control valve, constant speed control valve group, and drive motor A and drive motor B).

[0020] Figure 4 for Figure 2 A schematic diagram of the hydraulic principle.

[0021] The components are as follows: 1. Electro-proportional control valve; 2. Oil pump; 3. Oil tank; 4. Oil circuit; 5. Constant speed control valve assembly; 501. Speed ​​control valve; 502. Pressure relief valve; 6. Drive motor A; 7. Tool; 8. Boom; 9. Drive motor B; 10. Blade; 11. Return oil port; 12. T-joint; P, output of electro-proportional control valve; P0, input of electro-proportional control valve; P1, input of drive motor B; P2, input of speed control valve; P3, output of speed control valve; P4, input of drive motor A; T1, output of pressure relief valve; T2, output of drive motor A; T3, output of drive motor B. Detailed Implementation

[0022] The following examples are used to further illustrate the content of the present invention and do not limit the application of the present invention.

[0023] Please see Figures 1-4A hydraulic control system for composite actions of a machine tool includes an electro-proportional control valve 1 for hydraulic control, an oil pump 2 for supplying hydraulic oil to the electro-proportional control valve 1, an oil tank 3 for supplying hydraulic oil, and an oil circuit 4 for supplying hydraulic oil. The oil tank 3 is hydraulically connected to the electro-proportional control valve 1 via the oil pump 2. One of the electro-proportional control valves 1 is hydraulically controlled via the oil circuit 4 to a constant speed control valve group 5 for controlling the speed of a drive motor A6 and preventing overpressure of the drive motor A6. The constant speed control valve group 5 is hydraulically controlled to a drive motor A6 for driving the machine tool 7 to rotate. The drive motor A6 drives and connects to the machine tool 7 for driving the blade 10 to move. The drive motor A6 is fixed to the end side of the machine tool 7. The constant speed control valve group 5 is fixed to the edge of the machine tool 7. The upper end of the machine tool 7 is fixedly connected to a boom 8 for fixing the machine tool 7. The boom 8 is equipped with the oil circuit 4.

[0024] The constant speed control valve group 5 includes a speed regulating valve 501 for controlling the hydraulic oil pressure of the drive motor A6 and a pressure limiting valve 502 for cooperating with the speed regulating valve 501 to prevent overpressure of the drive motor A6. The input terminal P2 of the speed regulating valve 501 is connected to the output terminal P of the electro-proportional control valve 1 through the oil circuit 4. The output terminal of the speed regulating valve 501 is divided into two paths. One output terminal P3 of the speed regulating valve 501 is connected to the input terminal of the pressure limiting valve 502, and the other output terminal P3 of the speed regulating valve 501 is connected to the input terminal P4 of the drive motor A6. The output terminal T2 of the drive motor A6 and the output terminal T1 of the pressure limiting valve 502 are both connected to the oil tank 3 through the oil circuit 4.

[0025] Another path of the electro-proportional control valve 1 is hydraulically controlled by the oil circuit 4 to drive the drive motor B9 for rotating the blade 10. The drive motor B9 is fixed at the center of the tool 7. The drive motor B9 drives the blade 10 for trimming hedges. The blade 10 is fixed on three drive discs on the bottom outer periphery of the tool 7, so that the tool 7 and the blade 10 form a fan-shaped structure.

[0026] The output end T3 of the hydraulic motor B9 is connected to the oil tank 3 through the oil circuit 4. The input end P1 of the hydraulic motor B9 is connected to the output end P of the electro-proportional control valve 1 through the oil circuit 4. The input end P of the electro-proportional control valve 1 is connected to the oil tank 3 through the oil pump 2. The electro-proportional control valve 1 is also provided with a return oil port 11 for returning oil to the oil tank 3. The return oil port 11 is directly connected to the oil tank 3.

[0027] The control method for the compound actions of machinery of the present invention: such as Figures 1-4This diagram illustrates that after the hydraulic control system for the composite actions of the above-mentioned machine is set up, the composite actions of the machine are controlled using this hydraulic control system. Specifically: First, the hydraulic oil in the oil tank 3 is delivered to the electro-proportional control valve 1 through the oil pump 2. Then, the electro-proportional control valve 1 controls the total flow rate of the hydraulic oil output to 84-90 L / min. The hydraulic oil with a total flow rate of 84-90 L / min is then divided into two paths through the oil circuit 4 and the three-way pipe joint 12 (the basic structure of the existing three-way pipe joint, such as the multiple output lines, is not described in detail here, but this should not limit its functionality) for simultaneous control output: one path controls the output flow rate of 4-6 L / min of hydraulic oil through the speed regulating valve 501, and after being controlled by the pressure limiting valve 502, it is supplied to the drive motor A6, thus obtaining the drive of 4-6 L / min of hydraulic oil. Under the control of speed control valve 501 and pressure relief valve 502, motor A6 drives tool 7 to rotate around its central axis at a speed of 80 r / min. Meanwhile, the remaining hydraulic oil flow of 80-84 L / min (after subtracting the hydraulic oil flow of hydraulic motor A from the total hydraulic oil flow of 84-90 L / min) is directly supplied to drive motor B9. Drive motor B9, with its 80-84 L / min hydraulic oil flow, directly drives blade 10 to rotate at a speed of 2500 r / min. This achieves simultaneous rotation of tool 7 and blade 10 (the rotation directions of tool 7 and blade 10 are as follows). Figure 3 As shown by the arrow direction, when the blade 10 and the tool 7 are rotating, the hydraulic oil obtained by the drive motor A6 and the drive motor B9 are returned to the oil tank 3 through the oil circuit 4; when the blade 10 is overloaded, the hydraulic oil overflowing from the electro-proportional control valve 1 will return to the oil tank 3 through the return port 11, effectively avoiding the problem of damage to the hydraulic control system due to overpressure overload.

[0028] When the machine 7 stops due to obstruction during its rotation (i.e., the working pressure of the drive motor A6 is greater than the set pressure of the pressure relief valve 502), the pressure oil at the output of the speed control valve 501 can flow back to the oil tank 3 through the pressure relief valve 502, preventing overpressure damage to the drive motor A6. Since the speed control valve 501 is a pressure-compensated type, it is composed of a throttle valve and a differential pressure valve. The control flow rate of the speed control valve 501 depends on the size of the throttle valve opening and the pressure difference between the throttle valve inlet and outlet. The differential pressure valve's function is to stabilize the pressure difference between the throttle valve inlet and outlet. Therefore, when the load on the drive motor A6 is small, excessive flow through the throttle valve causes the pressure difference to exceed the preset value of the differential pressure valve. In this case, the constant pressure differential valve in the speed control valve group will close the oil outlet, reducing the flow rate through the throttle valve. The pressure difference is reduced to match the setting of the speed control valve 501, thus achieving the control purpose of limiting the hydraulic control oil output beyond the set flow rate. When the self-rotating motor encounters a large load, the control pressure of the electro-proportional control valve 1 is 20MPa, which is the control pressure of the drive motor A6. Since the working pressure of the drive motor A6 is 10MPa, and the pressure difference before and after the throttle valve set in the speed control valve 501 is a constant value, the hydraulic oil is preferentially supplied to the drive motor A6. Even if the drive motor A6 encounters a large load, the hydraulic oil can still drive the drive motor A6 to work through the speed control valve 501. It can be seen that the speed of the drive motor A6 is independent of the load size, and the oil flow rate depends only on the opening of the speed control valve.

[0029] When the rotation speed of the blade 10 needs to be adjusted, only the control signal of the electro-proportional control valve 1 needs to be adjusted; when the rotation speed of the tool 7 needs to be adjusted, only the control scale of the speed regulating valve 501 needs to be adjusted; when the tool 7 encounters a large tree trunk during its rotation, causing the working pressure of the drive motor A6 to exceed the set value of the pressure relief valve 502, the drive motor A6 will stop rotating, and the speed regulating valve 501 will overflow the hydraulic oil back into the oil tank 3 through the pressure relief valve A502, thus preventing damage to the drive motor A6 due to overload.

Claims

1. A hydraulic control system for compound actions of a machine tool, comprising an electro-proportional control valve, an oil pump, an oil tank, and oil circuits, wherein the oil tank is hydraulically connected to the electro-proportional control valve via the oil pump, characterized in that, The input end of the electro-proportional control valve is connected to the oil tank via an oil pump. The electro-proportional control valve also has a return port, which is directly connected to the oil tank. One path of the electro-proportional control valve hydraulically controls a constant speed control valve assembly, which in turn hydraulically controls a drive motor A. Drive motor A drives a workpiece, and a boom is fixedly connected to the upper end of the workpiece. An oil circuit is mounted on the boom. The other path of the electro-proportional control valve hydraulically controls a drive motor B, which drives a workpiece connected to a workpiece. The blade is fixed to the outer periphery of the bottom of the tool. The drive motor B is fixed to the center of the tool. The constant speed control valve group is fixed to the edge of the tool. The drive motor A is fixed to the end side of the tool. The constant speed control valve group includes a speed regulating valve and a pressure limiting valve. The input end of the speed regulating valve is connected to the output end of the electro-proportional control valve through an oil circuit. The output end of the speed regulating valve is divided into two paths: one path is connected to the input end of the pressure limiting valve, and the other path is connected to the input end of the drive motor A. The specific control method steps for the compound action of the machine are as follows: S1. The hydraulic oil in the oil tank is pumped to the electro-proportional control valve, wherein the total flow rate of the hydraulic oil is controlled by the electro-proportional control valve to output 84-90L / min; S2. The hydraulic oil input to the electro-proportional control valve is divided into two paths for simultaneous output control through the oil circuit and three-way pipe joint: one path of hydraulic oil is supplied to drive motor A through the speed regulating valve and the pressure limiting valve, and the other path of hydraulic oil is directly supplied to drive motor B. The hydraulic oil flow rate supplied to hydraulic motor A is controlled by the speed regulating valve and the pressure limiting valve to be 4-6 L / min, and the hydraulic oil flow rate supplied to hydraulic motor B is the total hydraulic oil flow rate minus the hydraulic oil flow rate of hydraulic motor A, which is 80-84 L / min. S3. Drive motor A, which obtains hydraulic oil, drives the machine to rotate under the control of speed control valve and pressure relief valve. Drive motor B, which obtains hydraulic oil, directly drives the blade to rotate. The speed of the machine is 80 r / min and the speed of the blade is 2500 r / min. S4. When the blade or tool is rotating, both drive motor A and drive motor B return the hydraulic oil in their respective oil circuits to the oil tank. When the blade is overloaded, the electro-proportional control valve returns the hydraulic oil overflowing due to overpressure inside its internal oil tank through the return oil port.

2. The hydraulic control system for composite actions of machinery according to claim 1, characterized in that, The outputs of both the drive motor A and the pressure relief valve are connected to the oil tank via oil lines.

3. The hydraulic control system for composite actions of machinery according to claim 1, characterized in that, The input end of the hydraulic motor B is connected to the output end of the electro-proportional control valve via an oil circuit, and the output end of the hydraulic motor B is connected to the oil tank via an oil circuit.

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