Pilot pressure stabilizing control system and control method thereof

Abstract

This invention discloses a pilot pressure stabilization control system and its control method. The control system includes a main oil circuit and a pilot control oil circuit. The main oil circuit includes an oil tank, a load-sensitive pump, a multi-way valve, and an actuator connected in sequence. The multi-way valve includes an unloading valve, a reversing valve, and a first check valve. The pilot control oil circuit includes a throttle orifice, a filter, a pilot pressure reducing valve, a second check valve, an accumulator, a safety solenoid valve, a pressure-regulating and pressure-reducing valve, and a pressure-regulating solenoid valve. The pilot control oil circuit consists of a reversing valve, a first check valve, an LS relief valve, an unloading valve, an LS pressure sensor, and a load-sensitive pump. The electrical control circuit consists of a controller, an LS pressure sensor, and a pressure-regulating solenoid valve. This invention, through monitoring and algorithms, confirms that the pilot pressure has decreased, and then increases the main pump outlet pressure, thereby increasing the pilot pressure and achieving the effect of stabilizing the pilot pressure.

Description

Technical Field

[0001] This invention relates to a pilot pressure stabilization control system and its control method, belonging to the field of hydraulic technology for engineering machinery. Background Technology

[0002] Typically, in a single-pump excavator, the pilot pressure oil comes from the pilot oil source block. It is depressurized by the pressure reducing valve before it can be used. After the pressure reducing valve, a check valve, accumulator, and solenoid valve are connected, which then leads to the next level of pilot control valves (handle, foot pedal, etc.). By controlling the switching of the multi-way valve, the working oil drives the actuators to reciprocate (boom, stick, bucket, swing, travel), thereby realizing the various actions of the excavator.

[0003] Due to the inherent structural and physical characteristics of hydraulic components, leakage is inevitable, leading to a decrease in internal pressure and compromising pressure stability. In pilot systems, accumulators are typically used to extend the stability of the pilot pressure.

[0004] In this application, due to the presence of leakage, although the accumulator has a pressure-holding function, the pilot pressure will still drop to the minimum system pressure (standby pressure). This will cause the pilot pressure to be lower than the required pressure value when there is no operation for a long time. At this time, operating the excavator is prone to causing delays, vibrations and other faults, resulting in insufficient control performance. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of the prior art and provide a pilot pressure stabilization control system and its control method. By monitoring and algorithms, it is confirmed that when the pilot pressure decreases, the main pump outlet pressure is increased, thereby increasing the pilot pressure and achieving the effect of stabilizing the pilot pressure.

[0006] To achieve the above objectives, the present invention is implemented using the following technical solution:

[0007] In a first aspect, the present invention provides a pilot pressure stabilization control system, comprising: a main oil circuit and a pilot control oil circuit;

[0008] The main oil circuit includes an oil tank, a load-sensitive pump, a multi-way valve, and an actuator connected in sequence. The multi-way valve includes an unloading valve, a reversing valve, and a first check valve. The unloading valve is connected to the load-sensitive pump and multiple reversing valves and the first check valve, and the multiple reversing valves and the first check valve are connected to multiple actuators one-to-one. The unloading valve includes at least a two-position reversing valve. The two-position reversing valve has at least a first working position and a second working position that can be reversed. When the two-position reversing valve is in the first working position, the P port of the load-sensitive pump is connected to the oil tank, and the pressure at the main pump outlet P is the minimum system pressure, which is used as the standby pressure. When the two-position reversing valve is in the second working position, the oil circuit connecting the P port of the load-sensitive pump to the oil tank is disconnected, and the pressure at the main pump outlet P is the actuator pressure.

[0009] The pilot control oil circuit includes a throttle orifice, a filter, a pilot pressure reducing valve, a second check valve, an accumulator, a safety solenoid valve, a pressure regulating and reducing valve, a pressure regulating solenoid valve, and a pilot pressure sensor. One end of the throttle orifice is connected to the load-sensitive pump, and the other end is connected to the pilot pressure oil through the filter, the pilot pressure reducing valve, the second check valve, the accumulator, and the safety solenoid valve in sequence. The pilot pressure oil is connected to the upper end face of the unloading valve through the pressure regulating and reducing valve and the pressure regulating solenoid valve. The pilot pressure sensor is located in the oil circuit between the safety solenoid valve and the accumulator.

[0010] Furthermore, the unloading valve is designed to determine whether to switch directions by comparing the pressure in the upper and lower chambers with the spring force, thereby controlling its operation in the first or second working position.

[0011] Furthermore, it also includes an LS control oil circuit, which consists of a directional valve, a first check valve, an LS relief valve, an unloading valve, an LS pressure sensor, and a load-sensitive pump. The LS relief valve is connected to the unloading valve, the LS control oil circuit, and the oil tank, respectively. The LS pressure sensor is connected to the LS control oil circuit and is used to collect pressure values.

[0012] Furthermore, it also includes an electrical control circuit, which consists of a controller, an LS pressure sensor, and a pressure-regulating solenoid valve. The controller is communicatively connected to the LS pressure sensor, the pressure-regulating solenoid valve, the safety solenoid valve, the pilot pressure sensor, and the pressure-regulating and reducing valve, respectively.

[0013] In a second aspect, the present invention provides a control method for a pilot pressure stabilization control system according to any one of the first aspects, the control method comprising:

[0014] The first step is for the controller to detect whether the safety solenoid valve is energized. If it is confirmed that the valve is not energized, the controller is in standby mode and does not issue any instructions, returning to the initial state of the control program. When the controller detects that the safety solenoid valve is energized, it proceeds to the next logical judgment.

[0015] The second step involves the controller determining the current pilot pressure oil level using the pilot pressure sensor and comparing it with the initially set threshold X bar. If the value is greater than the threshold X bar, the controller does not issue any instructions and returns to the initial state of the control program. Otherwise, if the value is less than the threshold X bar, the controller accumulates the duration for which the pressure is less than the initially set threshold X bar. If the accumulated time is less than the threshold Y s, the control program returns to the initial state. If the accumulated time is greater than the threshold Y s, the controller energizes the pressure regulating solenoid valve to switch directions.

[0016] When the controller executes the energization and reversal of the pressure regulating solenoid valve, the pressure oil in the pilot control oil circuit is connected to the upper end face of the unloading valve through the pressure regulating and reducing valve and the pressure regulating solenoid valve. At this time, the unloading valve continues to work in the first position. The standby pressure mentioned earlier needs to overcome the newly added pressure oil. Its magnitude is determined by the setting value of the pressure regulating and reducing valve. At this time, the outlet pressure of the load sensitive pump increases, and the pressure of the pilot pressure oil also increases accordingly to prevent the pilot pressure from dropping below the specified value.

[0017] Third, the controller determines the current pilot pressure level through the pilot pressure sensor. When the value is less than the threshold Z bar, the controller does not issue any instructions and continues to keep the pressure regulating solenoid valve energized and switched. When the value is greater than the threshold Z bar, the controller controls the pressure regulating solenoid valve to de-energize and reset, ending the pilot pressure stabilization control program and returning to the initial state of the control program. During this period, the pilot pressure continues to rise and reaches the set value, and the hydraulic oil in the accumulator is also fully charged to meet the requirements.

[0018] Thirdly, the present invention provides a pilot pressure stabilization control system, comprising: a main oil circuit and a pilot control oil circuit;

[0019] The main oil circuit includes an oil tank, a load-sensitive pump, a multi-way valve, and an actuator connected in sequence. The multi-way valve includes an unloading valve, a reversing valve, and a first check valve. The unloading valve is connected to the load-sensitive pump and multiple reversing valves and the first check valve, and the multiple reversing valves and the first check valve are connected to multiple actuators one-to-one. The unloading valve includes at least a two-position reversing valve. The two-position reversing valve has at least a first working position and a second working position that can be reversed. When the two-position reversing valve is in the first working position, the P port of the load-sensitive pump is connected to the oil tank, and the pressure at the main pump outlet P is the minimum system pressure, which is used as the standby pressure. When the two-position reversing valve is in the second working position, the oil circuit connecting the P port of the load-sensitive pump to the oil tank is disconnected, and the pressure at the main pump outlet P is the actuator pressure.

[0020] The pilot control oil circuit includes a throttle orifice, a filter, a pilot pressure reducing valve, a second check valve, an accumulator, a safety solenoid valve, a pressure stabilizing and reducing valve, and a pressure stabilizing solenoid valve. One end of the throttle orifice is connected to the load-sensitive pump, and the other end is connected to the pilot pressure oil through the filter, the pilot pressure reducing valve, the second check valve, the accumulator, and the safety solenoid valve in sequence. The pilot pressure oil is connected to the upper end face of the unloading valve through the pressure stabilizing and reducing valve and the pressure stabilizing solenoid valve.

[0021] Furthermore, the unloading valve is designed to determine whether to switch directions by comparing the pressure in the upper and lower chambers with the spring force, thereby controlling its operation in the first or second working position.

[0022] Furthermore, it also includes an LS control oil circuit, which consists of a directional valve, a first check valve, an LS relief valve, an unloading valve, an LS pressure sensor, and a load-sensitive pump. The LS relief valve is connected to the unloading valve, the LS control oil circuit, and the oil tank, respectively. The LS pressure sensor is connected to the LS control oil circuit and is used to collect pressure values.

[0023] Furthermore, it also includes an electrical control circuit, which consists of a controller, an LS pressure sensor, and a pressure-regulating solenoid valve. The controller is communicatively connected to the LS pressure sensor, the pressure-regulating solenoid valve, the safety solenoid valve, and the pressure-regulating and reducing valve, respectively.

[0024] Fourthly, the present invention provides a control method for a pilot pressure stabilization control system according to any one of the third aspects, the control method comprising:

[0025] The first step is for the controller to detect whether the safety solenoid valve is energized. If it is confirmed that the valve is not energized, the controller is in standby mode and does not issue any instructions, returning to the initial state of the control program. When the controller detects that the safety solenoid valve is energized, it proceeds to the next logical judgment.

[0026] The second step involves the controller determining the current LS pressure value using the LS pressure sensor and comparing it with the initially set threshold X bar. If the value is greater than the threshold X bar, it indicates that the vehicle is operating normally, and the controller does not issue any instructions, returning to the initial state of the control program. Otherwise, if the value is less than the threshold X bar, the controller begins to accumulate the duration of the time the value is less than the threshold X bar. During this period, if the accumulated time is less than the threshold Y s, the control program continues to accumulate the time until it exceeds the threshold Y s, at which point it proceeds to the next logical judgment.

[0027] The third step is for the controller to determine the current LS pressure value through the LS pressure sensor and compare it with the initially set threshold X bar. When the value is greater than the threshold X bar, the controller does not make any instructions and returns to the initial state of the control program. Otherwise, when the value is less than the threshold X bar, the controller then controls the pressure regulating solenoid valve to be energized and reversed.

[0028] When the controller executes the energization and reversal of the pressure regulating solenoid valve, the pilot pressure oil in the pilot control oil circuit is connected to the upper end face of the unloading valve through the pressure regulating and reducing valve and the pressure regulating solenoid valve. At this time, the unloading valve continues to work in the first position. The standby pressure mentioned earlier needs to overcome the newly added pressure oil. Its magnitude is determined by the setting value of the pressure regulating and reducing valve. At this time, the outlet pressure of the load sensitive pump increases, and the pilot pressure oil pressure also increases accordingly to prevent the pilot pressure from dropping below the specified value.

[0029] Fourth step: After the pressure regulating solenoid valve is energized and reversed, the controller starts to accumulate time and compares it with the threshold Ys. During this period, the pilot pressure continues to rise and reaches the set value, and the hydraulic oil in the accumulator is also fully charged to meet the requirements.

[0030] Fifth step: When the value is greater than the threshold Ys, the controller controls the pressure regulating solenoid valve to de-energize and reset, ending the pilot pressure stabilization control program and returning to the initial state of the control program.

[0031] Compared with the prior art, the beneficial effects achieved by the present invention are as follows:

[0032] This invention provides a pilot pressure stabilization control system and its control method. By monitoring and using algorithms, when the pilot pressure is confirmed to be low, the main pump outlet pressure is increased, thereby increasing the pilot pressure and achieving the effect of stabilizing the pilot pressure. Attached Figure Description

[0033] Figure 1 This is a schematic diagram of a pilot pressure stabilization control system provided in Embodiment 1 of the present invention;

[0034] Figure 2 Based on Figure 1 The electrical control diagram shown is shown below;

[0035] Figure 3 For based on Figure 1 The diagram shown is a logic control diagram.

[0036] Figure 4 This is a schematic diagram of a pilot pressure stabilization control system provided in Embodiment 2 of the present invention;

[0037] Figure 5 For based on Figure 4 The electrical control diagram shown is shown below;

[0038] Figure 6 For based on Figure 4 The diagram shown is a logic control diagram.

[0039] In the diagram: 1. Load-sensitive pump; 2. Throttling orifice; 3. Filter; 4. Pilot pressure reducing valve; 5. Second check valve; 6. Accumulator; 7. Safety solenoid valve; 8. Pressure regulating and reducing valve; 9. Pressure regulating solenoid valve; 10. Unloading valve; 11. LS relief valve; 12. First check valve; 13. Directional control valve; 14. Actuator; 15. LS pressure sensor; 16. Oil tank; 17. Pilot pressure sensor. Detailed Implementation

[0040] The present invention will be further described below with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and should not be used to limit the scope of protection of the present invention.

[0041] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0042] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art will understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0043] Example 1

[0044] like Figure 1 , Figure 2 , Figure 3 As shown in the figure, this embodiment introduces a pilot pressure stabilization control system, including: a main oil circuit, an LS control oil circuit, a pilot control oil circuit, and an electrical control circuit;

[0045] The main oil circuit is designed to control the working oil discharged from the outlet of the load-sensitive pump 1 through a multi-way valve to drive the actuator 14. It includes the load-sensitive pump 1, the multi-way valve, the actuator 14, and the oil tank 16.

[0046] The actuator 14 includes any number and type of hydraulic actuators such as cylinders and motors;

[0047] The multi-way valve includes an unloading valve 10, a reversing valve 13, and a first check valve 12; the number of the reversing valves 13 corresponds to the number of the actuators 14; the number of the first check valves 12 corresponds to the number of the reversing valves 13.

[0048] The unloading valve 10 is connected to the load-sensitive pump 1 and multiple directional valves 13 and first check valve 12 respectively. The multiple directional valves 13 and first check valve 12 are connected to multiple actuators 14 one-to-one.

[0049] The unloading valve 10 includes at least a two-position directional valve 13;

[0050] The two-position reversing valve 13 has at least a first working position and a second working position capable of reversing;

[0051] When the two-position reversing valve 13 is in the first working position, the P port of the load-sensitive pump 1 is connected to the oil tank 16. At this time, the pressure of the main pump outlet P is the minimum system pressure, which is used as the standby pressure.

[0052] When the two-position reversing valve 13 is in the second working position, the oil circuit connecting the P port of the load-sensitive pump 1 to the oil tank 16 is disconnected. At this time, the pressure of the main pump outlet P is the pressure of the actuator 14, which is the system working pressure.

[0053] The unloading valve 10 is designed to determine whether it should switch directions by comparing the pressure in the upper and lower chambers with the spring force, so as to control it to work in the first or second working position.

[0054] The LS control oil circuit is designed to control the actuator 14 via the reversing valve 13, providing feedback to the LS control oil to drive the variable displacement structure of the load-sensitive pump 1, thereby achieving flow control. Simultaneously, when multiple actuators 14 operate at the same time, the first check valve 12 in the LS control oil circuit selects the maximum pressure and feeds it back to the variable displacement mechanism of the load-sensitive pump 1, achieving flow control. The LS control oil circuit consists of the reversing valve 13, the first check valve 12, the LS relief valve 11, the unloading valve 10, the LS pressure sensor 15, and the load-sensitive pump 1. The LS relief valve 11 is connected to the unloading valve 10, the LS control oil circuit, and the oil tank 16, and is designed to limit the maximum LS pressure. The LS pressure sensor 15 is connected to the LS control oil circuit and is used to collect pressure values.

[0055] The pilot control oil circuit is designed to control the working oil discharged from the outlet of the load-sensitive pump 1 through pressure reduction and energy storage, providing pressure oil to the pilot system. Simultaneously, it further reduces the working oil pressure through the pressure-regulating and pressure-reducing valve 8 and switches the flow through the pressure-regulating solenoid valve 9 to provide control signal hydraulic oil to the unloading valve 10, causing it to switch operation. The pilot control oil circuit includes a throttle orifice 2, a filter 3, a pilot pressure-reducing valve 4, a second check valve 5, an accumulator 6, a safety solenoid valve 7, a pressure-regulating and pressure-reducing valve 8, a pressure-regulating solenoid valve 9, and a pilot pressure sensor 17. One end of the throttle orifice 2 is connected to the load-sensitive pump 1, and the other end is connected to the pilot pressure oil through the filter 3, pilot pressure-reducing valve 4, second check valve 5, accumulator 6, and safety solenoid valve 7. The pilot pressure oil is connected to the upper surface of the unloading valve 10 through the pressure-regulating and pressure-reducing valve 8 and the pressure-regulating solenoid valve 9. The pilot pressure sensor 17 is located in the oil circuit between the safety solenoid valve 7 and the accumulator 6.

[0056] The electrical control circuit consists of a controller, an LS pressure sensor 15, and a pressure regulating solenoid valve 9. The controller is communicatively connected to the LS pressure sensor 15, the pressure regulating solenoid valve 9, the safety solenoid valve 7, the pilot pressure sensor 17, and the pressure regulating and reducing valve 8.

[0057] The entire voltage stabilization process is as follows: After the excavator starts, the controller... Figure 3 The control logic shown is used to control the pilot pressure:

[0058] The first step is for the controller to detect whether the safety solenoid valve 7 is energized. If it is confirmed that the valve is not energized, it is determined that the machine is in standby mode and the operator has no intention of operating the machine. Therefore, the controller does not issue any instructions and returns to the initial state of the control program. When the safety solenoid valve 7 is detected to be energized, the next logical judgment is performed.

[0059] The second step involves the controller determining the current pilot pressure oil level using the pilot pressure sensor 17 and comparing it with the initially set threshold X bar. If the value is greater than the threshold X bar, the controller does not issue any instructions and returns to the initial state of the control program. Otherwise, if the value is less than the threshold X bar, the controller accumulates the duration for which the value is less than the initially set threshold X bar. If the accumulated time is less than the threshold Y s, the control program returns to the initial state. If the accumulated time is greater than the threshold Y s, the controller executes the next step: the pressure regulating solenoid valve 9 is energized and reversed.

[0060] When the controller executes the energization and reversal of the pressure regulating solenoid valve 9, the pressure oil in the pilot control oil circuit is connected to the upper end face of the unloading valve 10 through the pressure regulating and reducing valve 8 and the pressure regulating solenoid valve 9. At this time, the unloading valve 10 continues to work in the first position. The standby pressure mentioned above needs to overcome the newly added pressure oil. Its magnitude is determined by the setting value of the pressure regulating and reducing valve 8. Therefore, at this time, the outlet pressure of the load sensitive pump 1 increases, and the pilot pressure oil pressure also increases accordingly, thereby preventing the pilot pressure from dropping below the specified value.

[0061] Thirdly, the controller uses the pilot pressure sensor 17 to determine the current pilot pressure. When the value is less than the threshold Z bar, the controller does not issue any instructions and continues to energize and switch the pressure regulating solenoid valve 9. When the value is greater than the threshold Z bar, the controller de-energizes and resets the pressure regulating solenoid valve 9, ending the pilot pressure stabilization control program and returning to the initial state of the control program. During this process, the pilot pressure continuously rises and reaches the set value, and the hydraulic oil in the accumulator 6 is also fully charged to meet the requirements.

[0062] Example 2

[0063] This embodiment provides a control method for the pilot pressure stabilization control system according to any one of Embodiment 1, the control method comprising:

[0064] The first step is for the controller to detect whether the safety solenoid valve 7 is energized. If it is confirmed that the valve is not energized, the controller is in standby mode and does not issue any instructions, returning to the initial state of the control program. When the controller detects that the safety solenoid valve 7 is energized, it proceeds to the next logical judgment.

[0065] The second step involves the controller determining the current pilot pressure oil level using the pilot pressure sensor 17 and comparing it with the initially set threshold X bar. If the value is greater than the threshold X bar, the controller does not issue any instructions and returns to the initial state of the control program. Otherwise, if the value is less than the threshold X bar, the controller accumulates the duration for which the value is less than the initially set threshold X bar. If the accumulated time is less than the threshold Y s, the control program returns to the initial state. If the accumulated time is greater than the threshold Y s, the controller energizes the pressure regulating solenoid valve 9 to switch directions.

[0066] When the controller executes the energization and reversal of the pressure regulating solenoid valve 9, the pressure oil in the pilot control oil circuit is connected to the upper end face of the unloading valve 10 through the pressure regulating and reducing valve 8 and the pressure regulating solenoid valve 9. At this time, the unloading valve 10 continues to work in the first position. The standby pressure mentioned above needs to overcome the newly added pressure oil. Its magnitude is determined by the setting value of the pressure regulating and reducing valve 8. At this time, the outlet pressure of the load sensitive pump 1 increases, and the pilot pressure oil pressure also increases accordingly to prevent the pilot pressure from dropping below the specified value.

[0067] Third, the controller determines the current pilot pressure through the pilot pressure sensor 17. When the value is less than the threshold Z bar, the controller does not make any instructions and continues to keep the pressure regulating solenoid valve 9 energized and reversed. When the value is greater than the threshold Z bar, the controller controls the pressure regulating solenoid valve 9 to de-energize and reset, ending the pilot pressure stabilization control program and returning to the initial state of the control program. During this period, the pilot pressure continues to rise and reaches the set value, and the hydraulic oil in the accumulator 6 is also fully charged to meet the requirements.

[0068] Example 3

[0069] To further reduce costs, the pilot pressure sensor 17 was removed in Example 1. Stable control of the pilot pressure can also be achieved by changing the logic control program. This will be further explained in conjunction with Example 2:

[0070] Figure 4 , Figure 5 , Figure 6 A pilot pressure stabilization control system includes a main oil circuit, an LS control oil circuit, a pilot control oil circuit, and an electrical control circuit.

[0071] The main oil circuit is designed to control the working oil discharged from the outlet of the load-sensitive pump 1 through a multi-way valve to drive the actuator 14. It includes the load-sensitive pump 1, the multi-way valve, the actuator 14, and the oil tank 16.

[0072] The actuator 14 includes any number and type of hydraulic actuators such as cylinders and motors;

[0073] The multi-way valve includes an unloading valve 10, a reversing valve 13, and a first check valve 12; the number of the reversing valves 13 corresponds to the number of the actuators 14; the number of the first check valves 12 corresponds to the number of the reversing valves 13.

[0074] The unloading valve 10 is connected to the load-sensitive pump 1 and multiple directional valves 13 and first check valve 12 respectively. The multiple directional valves 13 and first check valve 12 are connected to multiple actuators 14 one-to-one.

[0075] The unloading valve 10 includes at least a two-position directional valve 13;

[0076] The two-position reversing valve 13 has at least a first working position and a second working position capable of reversing;

[0077] When the two-position reversing valve 13 is in the first working position, the P port of the load-sensitive pump 1 is connected to the oil tank 16. At this time, the pressure of the main pump outlet P is the minimum system pressure, which is used as the standby pressure.

[0078] When the two-position reversing valve 13 is in the second working position, the oil circuit connecting the P port of the load-sensitive pump 1 to the oil tank 16 is disconnected. At this time, the pressure of the main pump outlet P is the pressure of the actuator 14, which is the system working pressure.

[0079] The unloading valve 10 is designed to determine whether it should switch directions by comparing the pressure in the upper and lower chambers with the spring force, so as to control it to work in the first or second working position.

[0080] The LS control oil circuit is designed to control the actuator 14 via the reversing valve 13, providing feedback to the LS control oil to drive the variable displacement structure of the load-sensitive pump 1, thereby achieving flow control. Simultaneously, when multiple actuators 14 operate at the same time, the first check valve 12 in the LS control oil circuit selects the maximum pressure and feeds it back to the variable displacement mechanism of the load-sensitive pump 1, achieving flow control. The LS control oil circuit consists of the reversing valve 13, the first check valve 12, the LS relief valve 11, the unloading valve 10, the LS pressure sensor 15, and the load-sensitive pump 1. The LS relief valve 11 is connected to the unloading valve 10, the LS control oil circuit, and the oil tank 16, and is designed to limit the maximum LS pressure. The LS pressure sensor 15 is connected to the LS control oil circuit and is used to collect pressure values.

[0081] The pilot control oil circuit is designed to control the working oil discharged from the outlet of the load-sensitive pump 1 through pressure reduction and energy storage, providing pressure oil to the pilot system. At the same time, the working oil pressure is further reduced by the pressure-reducing valve 8 and switched by the pressure-reducing solenoid valve 9 to provide control signal hydraulic oil to the unloading valve 10 to switch its operation. The pilot control oil circuit includes a throttle orifice 2, a filter 3, a pilot pressure-reducing valve 4, a second check valve 5, an accumulator 6, a safety solenoid valve 7, a pressure-reducing valve 8, and a pressure-reducing solenoid valve 9. One end of the throttle orifice 2 is connected to the load-sensitive pump 1, and the other end is connected to the pilot pressure oil through the filter 3, the pilot pressure-reducing valve 4, the second check valve 5, the accumulator 6, and the safety solenoid valve 7 in sequence. The pilot pressure oil is connected to the upper end face of the unloading valve 10 through the pressure-reducing valve 8 and the pressure-reducing solenoid valve 9.

[0082] The electrical control circuit consists of a controller, an LS pressure sensor 15, and a pressure regulating solenoid valve 9. The controller is communicatively connected to the LS pressure sensor 15, the pressure regulating solenoid valve 9, the safety solenoid valve 7, and the pressure regulating and reducing valve 8.

[0083] The entire voltage stabilization process is as follows: After the excavator starts, the controller... Figure 6 The control logic shown is used to control the pilot pressure:

[0084] The first step is for the controller to detect whether the safety solenoid valve 7 is energized. If it is confirmed that the valve is not energized, it is determined that the machine is in standby mode and the operator has no intention of operating the machine. Therefore, the controller does not issue any instructions and returns to the initial state of the control program. When the safety solenoid valve 7 is detected to be energized, the next logical judgment is performed.

[0085] The second step is for the controller to determine the current LS pressure value through the LS pressure sensor 15 and compare it with the initial threshold X bar. When the value is greater than the threshold X bar, it means that the vehicle is working normally and the controller does not make any instructions and returns to the initial state of the control program. Otherwise, when the value is less than the threshold X bar, the controller begins to accumulate the duration of the time when the value is less than the threshold X bar.

[0086] Third, during this period, if the accumulated time of the controller is less than the threshold Y s, the control program continues to accumulate the time until it is greater than the threshold Y s and then enters the next logical judgment. This process is to determine whether the pilot system pressure has dropped to the lowest acceptable value due to internal leakage.

[0087] In the fourth step, the controller uses the LS pressure sensor 15 to determine the current LS pressure value and compares it with the initially set threshold X bar. If the value is greater than the threshold X bar, it indicates that the vehicle is operating normally, and the controller does not issue any instructions, returning to the initial state of the control program. Otherwise, if the value is less than the threshold X bar, the controller then energizes the pressure regulating solenoid valve 9 to switch directions. This process is to further determine whether the pilot pressure increased due to the operation of the entire machine during the timing in the third step, thereby causing the pilot pressure to rise. After two judgments, it is determined that the pilot pressure has been lower than the set value for an extended period, and therefore needs to be increased.

[0088] When the controller executes the energization and reversal of the pressure regulating solenoid valve 9, the pressure oil in the pilot control oil circuit is connected to the upper end face of the unloading valve 10 through the pressure regulating and reducing valve 8 and the pressure regulating solenoid valve 9. At this time, the unloading valve 10 continues to work in the first position. The standby pressure mentioned above needs to overcome the newly added pressure oil. Its magnitude is determined by the setting value of the pressure regulating and reducing valve 8. Therefore, at this time, the outlet pressure of the load sensitive pump 1 increases, and the pilot pressure oil pressure also increases accordingly, thereby preventing the pilot pressure from dropping below the specified value.

[0089] Fifth step: After the pressure regulating solenoid valve 9 is energized and reversed, the controller starts to accumulate time and compares it with the threshold Y s. During this period, the pilot pressure continues to rise and reaches the set value, and the hydraulic oil in the accumulator 6 is also fully charged to meet the requirements.

[0090] Step 6: When the value is greater than the threshold Ys, the controller controls the pressure regulating solenoid valve 9 to de-energize and reset, ending the pilot pressure stabilization control program and returning to the initial state of the control program.

[0091] Example 4

[0092] This embodiment provides a control method for the pilot pressure stabilization control system according to any one of Embodiment 3, the control method comprising:

[0093] The first step is for the controller to detect whether the safety solenoid valve 7 is energized. If it is confirmed that the valve is not energized, the controller is in standby mode and does not issue any instructions, returning to the initial state of the control program. When the controller detects that the safety solenoid valve 7 is energized, it proceeds to the next logical judgment.

[0094] The second step involves the controller determining the current LS pressure value using the LS pressure sensor 15 and comparing it with the initially set threshold X bar. If the value is greater than the threshold X bar, it indicates that the vehicle is operating normally, and the controller does not issue any instructions, returning to the initial state of the control program. Otherwise, if the value is less than the threshold X bar, the controller begins to accumulate the duration of the time the value is less than the threshold X bar. During this period, if the accumulated time is less than the threshold Y s, the control program continues to accumulate the time until it exceeds the threshold Y s, at which point it proceeds to the next logical judgment.

[0095] The third step is for the controller to determine the current LS pressure value through the LS pressure sensor 15 and compare it with the initial threshold X bar. When the value is greater than the threshold X bar, the controller does not make any instructions and returns to the initial state of the control program. Otherwise, when the value is less than the threshold X bar, the controller controls the pressure regulating solenoid valve 9 to be energized and reversed.

[0096] When the controller executes the energization and reversal of the pressure regulating solenoid valve 9, the pilot pressure oil in the pilot control oil circuit is connected to the upper end face of the unloading valve 10 through the pressure regulating and reducing valve 8 and the pressure regulating solenoid valve 9. At this time, the unloading valve 10 continues to work in the first position. The standby pressure mentioned above needs to overcome the newly added pressure oil. Its magnitude is determined by the setting value of the pressure regulating and reducing valve 8. At this time, the outlet pressure of the load sensitive pump 1 increases, and the pilot pressure oil pressure also increases accordingly to prevent the pilot pressure from dropping below the specified value.

[0097] Fourth step: After the pressure regulating solenoid valve 9 is energized and reversed, the controller starts to accumulate time and compares it with the threshold Y s. During this period, the pilot pressure continues to rise and reaches the set value, and the hydraulic oil in the accumulator 6 is also fully charged to meet the requirements.

[0098] Fifth step: When the value is greater than the threshold Ys, the controller controls the pressure regulating solenoid valve 9 to de-energize and reset, ending the pilot pressure stabilization control program and returning to the initial state of the control program.

[0099] This embodiment provides a pilot pressure stabilization control system that can ensure the pilot pressure is maintained at the required level based on control logic.

[0100] Among them, such as Figures 1-3 This is the high-end version (with the addition of a pilot pressure sensor 17). The main difference between this version and the simplified version mentioned above is the addition of a pilot pressure sensor 17. It directly collects the pilot pressure, identifies its magnitude, and determines whether it is low pressure.

[0101] Advantages: Simplified and precise control logic allows for more accurate and stable pilot pressure.

[0102] Disadvantages: The addition of a sensor increases the cost.

[0103] Among them, such as Figures 4-6 This is a simplified (reduced cost) version of the solution. The pilot pressure is controlled by experience. The "preset threshold Xs" in the logic control is actually the time it takes for the pilot pressure to decrease after testing. It is an experience-based judgment method obtained through testing, not an experience-based judgment method based on actual pressure.

[0104] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A pilot pressure stabilization control system, characterized in that, include: Main oil circuit and pilot control oil circuit; The main oil circuit includes an oil tank (16), a load-sensitive pump (1), a multi-way valve, and an actuator (14) connected in sequence; the multi-way valve includes an unloading valve (10), a directional valve (13), and a first check valve (12); the unloading valve (10) is connected to the load-sensitive pump (1) and multiple directional valves (13) and the first check valve (12), and the multiple directional valves (13) and the first check valve (12) are connected to multiple actuators (14) one-to-one; the unloading valve (10) includes at least a two-position directional valve (16). 13); The two-position directional valve (13) has at least a first working position and a second working position that can be switched; When the two-position directional valve (13) is in the first working position, the P port of the load-sensitive pump (1) is connected to the oil tank (16), and the pressure of the main pump outlet P is the minimum system pressure, which is used as the standby pressure; When the two-position directional valve (13) is in the second working position, the oil circuit connecting the P port of the load-sensitive pump (1) to the oil tank (16) is disconnected, and the pressure of the main pump outlet P is the actuator (14) pressure; The pilot control oil circuit includes a throttle orifice (2), a filter (3), a pilot pressure reducing valve (4), a second check valve (5), an accumulator (6), a safety solenoid valve (7), a pressure stabilizing and reducing valve (8), a pressure stabilizing solenoid valve (9), and a pilot pressure sensor (17). One end of the throttle orifice (2) is connected to the load-sensitive pump (1), and the other end is connected to the pilot oil circuit through the filter (3), the pilot pressure reducing valve (4), the second check valve (5), the accumulator (6), and the safety solenoid valve (7) in sequence. The pilot oil circuit passes through the pressure stabilizing and reducing valve (8) and the pressure stabilizing solenoid valve (9) in sequence, and then connects to the upper end face of the unloading valve (10). The pilot pressure sensor (17) is located on the oil circuit between the safety solenoid valve (7) and the accumulator (6).

2. The pilot pressure stabilization control system according to claim 1, characterized in that, The unloading valve (10) is designed to determine whether to switch directions by comparing the pressure in the upper and lower chambers with the spring force, so as to control its operation in the first or second working position.

3. A control method for the pilot pressure stabilization control system according to claim 2, characterized in that, The control method includes: The first step is for the controller to detect whether the safety solenoid valve (7) is energized. If it is confirmed that the valve is not energized, the controller is in standby mode and does not issue any instructions, returning to the initial state of the control program. When the safety solenoid valve (7) is energized, the next logical judgment is performed. In the second step, the controller determines the current pilot pressure oil level through the pilot pressure sensor (17) and compares it with the initially set threshold X bar. When the value is greater than the threshold X bar, the controller does not make any instructions and returns to the initial state of the control program. Otherwise, when the value is less than the threshold X bar, the controller accumulates the duration of time less than the initially set threshold X bar. If the accumulated time is less than the threshold Y s, the control program returns to the initial state. If the accumulated time is greater than the threshold Y s, the controller controls the pressure regulating solenoid valve (9) to be energized and reversed. When the controller executes the energization and reversal of the pressure regulating solenoid valve (9), the pressure oil in the pilot control oil circuit is connected to the upper end face of the unloading valve (10) through the pressure regulating and reducing valve (8) and the pressure regulating solenoid valve (9). At this time, the unloading valve (10) continues to work in the first position. The standby pressure mentioned above needs to overcome the newly added pressure oil. Its size is determined by the setting value of the pressure regulating and reducing valve (8). At this time, the outlet pressure of the load sensitive pump (1) increases, and the pressure of the pilot pressure oil also increases accordingly to prevent the pilot pressure from dropping below the specified value. In the third step, the controller determines the magnitude of the pilot pressure at this moment through the pilot pressure sensor (17). When the value is less than the threshold Zbar, the controller does not make any instructions and continues to keep the pressure regulating solenoid valve (9) energized and reversed. When the value is greater than the threshold Zbar, the controller controls the pressure regulating solenoid valve (9) to de-energize and reset, ends the pilot pressure stabilization control program, and returns to the initial state of the control program. During this period, the pilot pressure continues to rise and reaches the set value, and the hydraulic oil in the accumulator (6) is also fully filled to meet the requirements.

4. A pilot pressure stabilization control system, characterized in that, include: Main oil circuit and pilot control oil circuit; The main oil circuit includes an oil tank (16), a load-sensitive pump (1), a multi-way valve, and an actuator (14) connected in sequence; the multi-way valve includes an unloading valve (10), a directional valve (13), and a first check valve (12); the unloading valve (10) is connected to the load-sensitive pump (1) and multiple directional valves (13) and the first check valve (12), and the multiple directional valves (13) and the first check valve (12) are connected to multiple actuators (14) one-to-one; the unloading valve (10) includes at least a two-position directional valve (16). 13); The two-position directional valve (13) has at least a first working position and a second working position that can be switched; When the two-position directional valve (13) is in the first working position, the P port of the load-sensitive pump (1) is connected to the oil tank (16), and the pressure of the main pump outlet P is the minimum system pressure, which is used as the standby pressure; When the two-position directional valve (13) is in the second working position, the oil circuit connecting the P port of the load-sensitive pump (1) to the oil tank (16) is disconnected, and the pressure of the main pump outlet P is the actuator (14) pressure; The pilot control oil circuit includes a throttle orifice (2), a filter (3), a pilot pressure reducing valve (4), a second check valve (5), an accumulator (6), a safety solenoid valve (7), a pressure stabilizing and reducing valve (8), and a pressure stabilizing solenoid valve (9). One end of the throttle orifice (2) is connected to the load-sensitive pump (1), and the other end is connected to the pilot oil circuit through the filter (3), the pilot pressure reducing valve (4), the second check valve (5), the accumulator (6), and the safety solenoid valve (7) in sequence. The pilot oil circuit is connected to the upper end face of the unloading valve (10) after passing through the pressure stabilizing and reducing valve (8) and the pressure stabilizing solenoid valve (9) in sequence.

5. The pilot pressure stabilization control system according to claim 4, characterized in that, The unloading valve (10) is designed to determine whether to switch directions by comparing the pressure in the upper and lower chambers with the spring force, so as to control its operation in the first or second working position.

6. A control method for a pilot pressure stabilization control system according to claim 5, characterized in that, The control method includes: The first step is for the controller to detect whether the safety solenoid valve (7) is energized. If it is confirmed that the valve is not energized, the controller is in standby mode and does not issue any instructions, returning to the initial state of the control program. When the safety solenoid valve (7) is energized, the next logical judgment is performed. The second step is for the controller to determine the current LS pressure value through the LS pressure sensor (15) and compare it with the initial threshold X bar. When the value is greater than the threshold X bar, it means that the vehicle is working normally and the controller does not make any instructions and returns to the initial state of the control program. Otherwise, when the value is less than the threshold X bar, the controller starts to accumulate the duration of time less than the threshold X bar. During this period, if the accumulated time of the controller is less than the threshold Y s, the control program continues to accumulate time until it is greater than the threshold Y s and then enters the next logical judgment. The third step is for the controller to determine the LS pressure value at this moment through the LS pressure sensor (15) and compare it with the initial threshold X bar. When the value is greater than the threshold X bar, the controller does not make any instructions and returns to the initial state of the control program. Otherwise, when the value is less than the threshold X bar, the controller controls the pressure regulating solenoid valve (9) to be energized and reversed. When the controller executes the energization and reversal of the pressure regulating solenoid valve (9), the pilot pressure oil in the pilot control oil circuit is connected to the upper end face of the unloading valve (10) through the pressure regulating and reducing valve (8) and the pressure regulating solenoid valve (9). At this time, the unloading valve (10) continues to work in the first position. The standby pressure mentioned above needs to overcome the newly added pressure oil. Its size is determined by the setting value of the pressure regulating and reducing valve (8). At this time, the outlet pressure of the load sensitive pump (1) increases, and the pressure of the pilot pressure oil also increases accordingly to prevent the pilot pressure from dropping below the specified value. In the fourth step, after the pressure regulating solenoid valve (9) is energized and reversed, the controller starts to accumulate time and compares it with the threshold Y s. During this period, the pilot pressure continues to rise and reaches the set value, and the hydraulic oil in the accumulator (6) is also fully filled to meet the requirements. Fifth step: When the value is greater than the threshold Y s, the controller controls the pressure regulating solenoid valve (9) to de-energize and reset, ending the pilot pressure stabilization control program and returning to the initial state of the control program.

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