An energy-saving control system and a hydraulic control device for excavators

Abstract

This application discloses an energy-saving control system and an excavator hydraulic control device, relating to the field of hydraulic control technology. The energy-saving control system includes an energy-saving motor, a differential regeneration valve, an energy-saving circuit, and / or a first directional valve. The energy-saving motor is connected to the shaft end of the hydraulic pump group of the excavator hydraulic control system. The oil outlet of the energy-saving motor is connected to the return oil channel through an unloading oil circuit. The differential regeneration valve is connected between the rodless chamber oil circuit and the rod chamber oil circuit of the boom cylinder assembly of the excavator hydraulic control system. The energy-saving circuit is connected to the rodless chamber oil circuit of the boom cylinder assembly. The energy-saving circuit is equipped with a flow extraction valve group, a take-up and release valve group, and an accumulator. The take-up and release valve group is connected to the oil inlet of the energy-saving motor. The first directional valve is connected between the oil outlet of the energy-saving motor and the output oil circuit of the hydraulic pump group of the excavator hydraulic control system. The above-mentioned energy-saving control system solves the problems of low working efficiency, large energy loss, and high temperature rise in the excavator hydraulic system.

Description

Technical Field

[0001] This application relates to the field of hydraulic control technology, and in particular to an energy-saving control system and a hydraulic control device for excavators. Background Technology

[0002] Currently, excavators typically use two variable displacement pumps and one pilot fixed displacement pump to supply oil to the hydraulic system. The excavator operation process is divided into four stages: digging, loading, unloading, and resetting.

[0003] In related technologies, during the loading stage, to load materials onto the vehicle, the excavator needs to raise its working device to a certain height. This process not only performs positive work on the material but also on the working device, causing it to accumulate a large amount of gravitational potential energy. This gravitational potential energy is typically lost through the hydraulic system during the device's descent. Therefore, during excavator operation, the descent of the working device results in a significant energy loss through the hydraulic system. This lost energy is often converted into heat loss rather than useful work, leading to low efficiency, high energy loss, and increased temperature within the excavator's hydraulic system. Summary of the Invention

[0004] The purpose of this application is to provide an energy-saving control system and an excavator hydraulic control device, which solves the problems of low working efficiency, large energy loss and high temperature rise in the excavator hydraulic system.

[0005] To achieve the above objectives, this application provides an energy-saving control system for an excavator hydraulic control system, comprising:

[0006] An energy-saving motor is used to connect to the shaft end of the hydraulic pump unit of the excavator's hydraulic control system. The oil outlet of the energy-saving motor is connected to the return oil channel through the unloading oil circuit.

[0007] A differential regeneration valve is used to connect the rodless chamber oil passage and the rod chamber oil passage of the boom cylinder assembly in the hydraulic control system of an excavator.

[0008] An energy-saving circuit is used to connect to the rodless chamber oil circuit of the boom cylinder assembly in the excavator's hydraulic control system. The energy-saving circuit includes a flow extraction valve assembly, a take-up and release valve assembly, and an accumulator. This allows the hydraulic oil in the rodless chamber oil circuit of the boom cylinder assembly to flow into the accumulator via the flow extraction valve assembly and the take-up and release valve assembly. The take-up and release valve assembly is connected to the oil inlet of the energy-saving motor; and / or

[0009] The first directional valve is used to connect between the oil outlet of the energy-saving motor and the output oil circuit of the hydraulic pump group of the excavator's hydraulic control system, so that the hydraulic oil output by the energy-saving motor flows to the output oil circuit of the hydraulic pump group.

[0010] In some embodiments, the flow extraction valve assembly includes a first flow extraction valve and a second flow extraction valve. The second flow extraction valve is located between the first flow extraction valve and the oil intake / discharge valve assembly. The first pilot oil passage of the second flow extraction valve is connected to the oil inlet of the first flow extraction valve, and the second pilot oil passage of the second flow extraction valve is connected to the oil outlet of the first flow extraction valve, so that the pressure difference between the oil inlet and the oil outlet of the first flow extraction valve is maintained at a set value.

[0011] In some embodiments, the flow extraction valve assembly further includes a third flow extraction valve, wherein a first pilot oil passage of the third flow extraction valve is connected to the inlet of the first flow extraction valve, a second pilot oil passage of the third flow extraction valve is connected to the outlet of the second flow extraction valve, and the third flow extraction valve is also connected to a return oil channel, so as to divert the hydraulic oil at the outlet of the second flow extraction valve to the return oil channel when the pressure difference between the inlet of the first flow extraction valve and the outlet of the second flow extraction valve meets a preset condition.

[0012] In some embodiments, the energy-saving control system further includes:

[0013] Electro-proportional control valves are used to control the displacement of energy-saving motors.

[0014] The first electro-proportional pilot valve is used to control the operation of the differential regeneration valve;

[0015] The second electro-proportional pilot valve is used to control the operation of the first flow extraction valve.

[0016] The controller is communicatively connected to the electro-proportional control valve, the first electro-proportional pilot valve, and the second electro-proportional pilot valve. It is used to send signals to the electro-proportional control valve to control the displacement of the energy-saving motor, and also to send signals to the first electro-proportional pilot valve and the second electro-proportional pilot valve to control the operation of the differential regeneration valve and the first flow extraction valve, respectively.

[0017] In some embodiments, the energy-saving control system further includes a first pressure sensor and a second pressure sensor, which are used to detect the pressure of the oil intake / discharge valve assembly and the accumulator, respectively. The third flow extraction valve, the first pressure sensor, and the second pressure sensor are all communicatively connected to the controller. The controller is also used to control the third flow extraction valve to operate according to the pressure detected by the first pressure sensor and the second pressure sensor, so as to divert the hydraulic oil at the outlet of the second flow extraction valve to the return oil channel.

[0018] In some embodiments, the energy-saving control system further includes a second directional valve connected between the oil outlet of the energy-saving motor and the oil recovery valve assembly, so that the hydraulic oil output by the energy-saving motor flows to the accumulator through the oil recovery valve assembly.

[0019] In some embodiments, a third directional valve is provided on the unloading oil circuit, and the energy-saving control system further includes a solenoid valve connected to the third directional valve so that unloading is performed by the third directional valve and the solenoid valve when the hydraulic oil pressure at the outlet of the energy-saving motor exceeds a threshold.

[0020] In some embodiments, the energy-saving control system further includes a pressure relief valve connected in parallel with the third directional valve.

[0021] In some embodiments, the oil inlet of the energy-saving motor is connected to a one-way valve assembly, which is connected to the oil return channel and the oil tank, so that the oil inlet of the energy-saving motor can draw oil from the oil tank or the oil return channel through the one-way valve assembly.

[0022] This application also provides a hydraulic control device for an excavator, including an excavator hydraulic control system. The excavator hydraulic control system includes a hydraulic pump group, a boom cylinder assembly, and a multi-way valve. The multi-way valve is connected to the output oil circuit of the hydraulic pump group and the rodless chamber oil circuit and the rod chamber oil circuit of the boom cylinder assembly to control the movement of the boom cylinder assembly. It also includes an energy-saving control system, wherein the energy-saving motor of the energy-saving control system is connected to the shaft end of the hydraulic pump group, the differential regeneration valve of the energy-saving control system is connected between the rodless chamber oil circuit and the rod chamber oil circuit of the boom cylinder assembly, the energy-saving circuit of the energy-saving control system is connected to the rodless chamber oil circuit of the boom cylinder assembly, and the first directional valve of the energy-saving control system is connected between the oil outlet of the energy-saving motor and the output oil circuit of the hydraulic pump group.

[0023] Compared to the background technology described above, the energy-saving control system provided in this application embodiment is used in the hydraulic control system of an excavator. The energy-saving control system includes an energy-saving motor, a differential regeneration valve, an energy-saving circuit, and / or a first directional valve. The energy-saving motor is connected to the shaft end of the hydraulic pump group of the excavator hydraulic control system. The oil outlet of the energy-saving motor is connected to the return oil channel through an unloading oil circuit. The differential regeneration valve is connected between the rodless chamber oil circuit and the rod chamber oil circuit of the boom cylinder assembly of the excavator hydraulic control system. The energy-saving circuit is connected to the rodless chamber oil circuit of the boom cylinder assembly of the excavator hydraulic control system. Further, the energy-saving circuit is provided with a flow extraction valve group, a take-up and release valve group, and an accumulator, so that the hydraulic oil in the rodless chamber oil circuit of the boom cylinder assembly is controlled by the flow extraction valve group and flows into the accumulator through the take-up and release valve group. The take-up and release valve group is connected to the oil inlet of the energy-saving motor. The first directional valve is connected between the oil outlet of the energy-saving motor and the output oil circuit of the hydraulic pump group of the excavator hydraulic control system, so that the hydraulic oil output by the energy-saving motor flows to the output oil circuit of the hydraulic pump group.

[0024] In this way, when the excavator is in energy-saving mode, the energy-saving motor, differential regeneration valve, flow extraction valve group, oil recovery and discharge valve group, accumulator, and / or first directional valve are opened. Specifically, when the operator lowers the boom cylinder assembly of the excavator's hydraulic control system, the differential regeneration valve is activated, and the rodless and rod chambers of the boom cylinder assembly are differentially connected. At this time, the rodless and rod chambers of the boom cylinder assembly are connected. On the one hand, in the differential state, the rodless chamber of the boom cylinder assembly supplies oil to the rod chamber. On the other hand, the excess high-pressure oil in the rodless chamber of the boom cylinder assembly enters the oil recovery and discharge valve group through the flow extraction valve group, and finally enters the accumulator, completing the energy recovery during the lowering process of the boom cylinder assembly. When the excavator is in the energy release process, when the accumulator reaches the release condition, the accumulator releases the recovered high-pressure oil. The high-pressure oil enters the oil inlet of the energy-saving motor and flows through the oil outlet of the energy-saving motor to the return oil passage via the unloading oil circuit. During the operation of the energy-saving motor, the energy-saving motor provides torque assistance to the shaft end of the engine-hydraulic pump group of the excavator's hydraulic control system to balance the engine load, reduce engine output, and achieve energy saving; and / or, the accumulator releases the recovered high-pressure oil, which enters the oil inlet of the energy-saving motor and supplies oil through the first reversing valve to the output oil circuit of the hydraulic pump group of the excavator's hydraulic control system via the oil outlet of the energy-saving motor. In this way, energy saving is achieved by providing hydraulic energy to the excavator's hydraulic control system.

[0025] The beneficial effects of this energy-saving control system mainly include: the energy-saving control system provided in this application embodiment allows the excavator to operate in energy-saving mode for extended periods, thereby maximizing the energy recovery and utilization of the boom cylinder assembly of the excavator's hydraulic control system. The recovered energy can be used to drive the energy-saving motor to output torque to the engine of the excavator's hydraulic control system in reverse, or it can be directly used to supply oil to the excavator's hydraulic control system, achieving energy-saving effects throughout the motor's operation. This ensures that the recovered hydraulic energy is utilized to the maximum extent, thereby reducing the engine power output of the excavator's hydraulic control system, reducing the heat generation of the excavator's hydraulic control system, reducing energy consumption, and improving operating efficiency. This solves the problems of low operating efficiency, large energy loss, and high temperature rise in the excavator's hydraulic system. Attached Figure Description

[0026] To more clearly illustrate the technical solutions in the embodiments of this application or related technologies, the drawings used in the description of the embodiments or related technologies will be briefly introduced below. Obviously, the drawings described below are only embodiments of this application. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0027] Figure 1 This is a hydraulic schematic diagram of the first energy-saving control system and the hydraulic control system of the excavator in this application;

[0028] Figure 2 This is a hydraulic schematic diagram of the second energy-saving control system and the hydraulic control system of the excavator in this application;

[0029] Figure 3 This is a hydraulic schematic diagram of the third energy-saving control system and the hydraulic control system of the excavator in this application;

[0030] Figure 4 for Figure 1 The flowchart shown is a process flow diagram of the energy recovery control system.

[0031] Figure 5 for Figure 1 The flowchart shown is a flow chart of the energy-saving control system releasing energy.

[0032] in:

[0033] 10-Energy-saving control system, 11-Energy-saving motor, 12-Unloading oil circuit, 13-Return oil channel, 14-Differential regeneration valve, 15-Energy-saving circuit, 16-Flow extraction valve assembly, 161-First flow extraction valve, 162-Second flow extraction valve, 163-Third flow extraction valve, 17-Oil recovery and discharge valve assembly, 18-Accumulator, 19-First reversing valve assembly, 191-First reversing valve, 192-Second reversing valve, 110-Second reversing valve assembly, 1101-Third reversing valve, 1102-Solenoid valve, 1103-Pressure relief valve, 111-Check valve assembly, 112-Electro-proportional control valve, 113-First electro-proportional pilot valve, 114-Second electro-proportional pilot valve, 115-Controller, 116-First pressure sensor, 117-Second pressure sensor, 118-Third pressure sensor, 119-Oil tank;

[0034] 20- Excavator hydraulic control system, 21- First pump, 211- Fourth pressure sensor, 22- Second pump, 221- Fifth pressure sensor, 23- Boom cylinder assembly, 24- Multi-way valve, 241- Boom confluence valve, 242- Boom control valve, 25- Engine. Detailed Implementation

[0035] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0036] To enable those skilled in the art to better understand the present application, the present application will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0037] Please see Figure 1 , Figure 4 and Figure 5 The energy-saving control system 10 provided in this application embodiment is used in the hydraulic control system 20 of an excavator. The energy-saving control system 10 includes an energy-saving motor 11, a differential regeneration valve 14, an energy-saving circuit 15 and / or a first directional valve 191.

[0038] It should be noted that the excavator hydraulic control system 20 includes a hydraulic pump group, a boom cylinder assembly 23 and a multi-way valve 24. The multi-way valve 24 is connected to the output oil circuit of the hydraulic pump group and the rodless chamber oil circuit and the rod chamber oil circuit of the boom cylinder assembly 23 to control the movement of the boom cylinder assembly 23. The hydraulic pump set includes a first pump 21 and a second pump 22. An energy-saving motor 11 (also called a variable displacement motor) is directly connected in series on the shaft ends of the first pump 21 and the second pump 22. The oil outlet of the energy-saving motor 11 is connected to the return oil channel 13 through the unloading oil passage 12. A differential regeneration valve 14 is added between the multi-way valve 24 and the boom cylinder assembly 23. The differential regeneration valve 14 is connected between the rodless chamber oil passage and the rod chamber oil passage of the boom cylinder assembly 23. The energy-saving circuit 15 of the energy-saving control system 10 is connected to the rodless chamber oil passage of the boom cylinder assembly 23. The first directional valve 191 of the energy-saving control system 10 is connected between the oil outlet of the energy-saving motor 11 and the output oil passage of the hydraulic pump set.

[0039] Furthermore, the energy-saving circuit 15 is equipped with a flow extraction valve group 16, a take-up and drain valve group 17, and an accumulator 18, so that the hydraulic oil in the rodless chamber oil circuit of the boom cylinder assembly 23 is controlled by the flow extraction valve group 16 and flows into the accumulator 18 through the take-up and drain valve group 17. The take-up and drain valve group 17 is connected to the oil inlet of the energy-saving motor 11. The first directional valve 191 is used to connect between the oil outlet of the energy-saving motor 11 and the output oil circuit of the hydraulic pump group of the excavator hydraulic control system 20, so that the hydraulic oil output by the energy-saving motor 11 flows to the output oil circuit of the hydraulic pump group.

[0040] At the same time, all solenoid valves in the system are controlled by the output signal of controller 115.

[0041] When the excavator is in energy-saving mode, the energy-saving motor 11, differential regeneration valve 14, flow extraction valve group 16, oil recovery and discharge valve group 17, accumulator 18, and / or first directional valve 191 are opened. Specifically, when the operator lowers the boom cylinder assembly 23 of the excavator's hydraulic control system 20, the differential regeneration valve 14 is activated, and the rodless chamber and rod chamber of the boom cylinder assembly 23 are differentially connected. At this time, the rodless chamber and rod chamber of the boom cylinder assembly 23 are in communication. On the one hand, in the differential state, the rodless chamber of the boom cylinder assembly 23 supplies oil to the rod chamber. On the other hand, the excess high-pressure oil in the rodless chamber of the boom cylinder assembly 23 enters the oil recovery and discharge valve group 17 through the flow extraction valve group 16, and finally enters the accumulator 18, completing the energy recovery during the lowering process of the boom cylinder assembly 23.

[0042] Please refer to the following: Figure 2 When the excavator is in the energy release process, when the accumulator 18 reaches the release condition, as the first energy release method: the accumulator 18 releases the recovered high-pressure oil. The high-pressure oil enters the oil inlet of the energy-saving motor 11, and flows through the oil outlet of the energy-saving motor 11 to the unloading oil passage 12 and the return oil passage 13. During the operation of the energy-saving motor 11, the energy-saving motor 11 provides torque assistance to the shaft end of the engine 25-hydraulic pump group of the excavator hydraulic control system 20 to balance the load of the engine 25, reduce the output of the engine 25, and achieve energy saving; please refer to the following: Figure 3 As a second energy release method, the accumulator 18 releases the recovered high-pressure oil, which enters the oil inlet of the energy-saving motor 11 and is supplied to the output oil circuit of the hydraulic pump group of the excavator hydraulic control system 20 through the oil outlet of the energy-saving motor 11 via the first reversing valve 191. In this way, energy saving is achieved by providing hydraulic energy to the excavator hydraulic control system 20.

[0043] This application can use the first energy release method and / or the second energy release method to release energy.

[0044] The energy-saving control system 10 provided in this application embodiment enables the excavator to operate in energy-saving mode for extended periods, thereby maximizing the energy recovery and utilization of the boom cylinder assembly 23 of the excavator hydraulic control system 20. The recovered energy can be used to drive the energy-saving motor 11 to output torque to the engine 25 of the excavator hydraulic control system 20 in reverse, or it can be directly used to supply oil to the excavator hydraulic control system 20, achieving energy-saving effects throughout the motor's operation. This ensures that the recovered hydraulic energy is utilized to the maximum extent, thereby reducing the power output of the engine 25 of the excavator hydraulic control system 20, reducing the heat generation of the excavator hydraulic control system 20, lowering energy consumption, and improving operating efficiency. This solves the problems of low operating efficiency, large energy loss, and high temperature rise in the excavator hydraulic system.

[0045] The following is combined Figure 1 , Figure 4and Figure 5 The structure of the energy-saving control system 10 will be explained in detail.

[0046] The flow extraction valve assembly 16 includes a first flow extraction valve 161 and a second flow extraction valve 162. The second flow extraction valve 162 is connected between the first flow extraction valve 161 and the oil intake / discharge valve assembly 17. The first pilot oil passage of the second flow extraction valve 162 is connected to the oil inlet of the first flow extraction valve 161, and the second pilot oil passage of the second flow extraction valve 162 is connected to the oil outlet of the first flow extraction valve 161, so that the pressure difference between the oil inlet and the oil outlet of the first flow extraction valve 161 is maintained at a set value.

[0047] During energy recovery, the second flow extraction valve 162 controls the pressure at the inlet and outlet of the first flow extraction valve 161 via the first and second pilot oil circuits, respectively, to control the flow rate through the first flow extraction valve 161. In other words, the second flow extraction valve 162 acts as a downstream pressure compensation valve for the first flow extraction valve 161, stably controlling the pressure difference across the first flow extraction valve 161 to control its flow rate, thereby controlling the boom descent speed and the recovered high-pressure flow.

[0048] Furthermore, the flow extraction valve assembly 16 also includes a third flow extraction valve 163. The first pilot oil passage of the third flow extraction valve 163 is connected to the inlet of the first flow extraction valve 161, and the second pilot oil passage of the third flow extraction valve 163 is connected to the outlet of the second flow extraction valve 162. The third flow extraction valve 163 is also connected to the return oil channel 13 so that when the pressure difference between the inlet of the first flow extraction valve 161 and the outlet of the second flow extraction valve 162 meets the preset conditions, the hydraulic oil at the outlet of the second flow extraction valve 162 is diverted to the return oil channel 13.

[0049] It should be noted that the pressure difference between the inlet of the first flow extraction valve 161 and the outlet of the second flow extraction valve 162 meeting the preset conditions means that the pressure difference between the inlet of the first flow extraction valve 161 and the outlet of the second flow extraction valve 162 is less than a certain minimum value, or that the pressure at the outlet of the second flow extraction valve 162 is greater than a certain maximum value.

[0050] Understandably, when the outlet pressure of the second flow extraction valve 162 or the inlet pressure of the oil inlet of the oil inlet valve assembly 17 exceeds a certain maximum value, it indicates that the storage set pressure of the accumulator 18 has been reached. At this time, in order to ensure that the outlet pressure of the second flow extraction valve 162 or the inlet pressure of the oil inlet of the oil inlet valve assembly 17 does not exceed the storage set pressure of the accumulator 18, it is necessary to unload the hydraulic oil in the energy-saving circuit 15.

[0051] In this way, the third flow extraction valve 163, as the differential pressure compensation valve between the inlet and outlet of the flow extraction valve group 16, controls the pressure at the inlet of the first flow extraction valve 161 and the outlet of the second flow extraction valve 162 through its first pilot oil circuit and second pilot oil circuit, respectively. When the pressure difference between the inlet of the first flow extraction valve 161 and the outlet of the second flow extraction valve 162 is less than a certain minimum value, or when the pressure at the outlet of the second flow extraction valve 162 is greater than a certain maximum value, the hydraulic oil at the outlet of the second flow extraction valve 162 is diverted to the return oil channel 13. This ensures that the pressure at the outlet of the second flow extraction valve 162 or the pressure at the inlet of the oil release valve group 17 does not exceed the storage set pressure of the accumulator 18.

[0052] It should be emphasized that the flow extraction valve assembly 16 is a flow control valve assembly with dual differential pressure control. During the energy recovery process, on the one hand, the second flow extraction valve 162, as the downstream pressure compensation valve of the first flow extraction valve 161, can stably control the pressure difference before and after the first flow extraction valve 161 to control the flow rate through the first flow extraction valve 161, so as to control the boom descent speed and the recovered high-pressure flow rate; on the other hand, the third flow extraction valve 163, as the differential pressure compensation valve between the inlet and outlet of the flow extraction valve assembly 16, can ensure that the outlet pressure of the second flow extraction valve 162 or the inlet pressure of the oil recovery and discharge valve assembly 17 does not exceed the storage set pressure of the accumulator 18.

[0053] Therefore, by controlling the opening degree of the first flow extraction valve 161 in the differential regeneration valve 14 and the flow extraction valve group 16, the speed of boom descent can be controlled while realizing energy recovery during boom descent, and the energy storage of accumulator 18 can be kept from overload. This ensures both the overall machine's operability and stable energy recovery.

[0054] In some embodiments, the energy-saving control system 10 further includes an electro-proportional control valve 112, a first electro-proportional pilot valve 113, a second electro-proportional pilot valve 114, and a controller 115.

[0055] Among them, the electro-proportional control valve 112 is connected to the energy-saving motor 11 and is used to control the displacement of the energy-saving motor 11; the first electro-proportional pilot valve 113 is connected to the differential regeneration valve 14 and is used to control the operation of the differential regeneration valve 14; the second electro-proportional pilot valve 114 is connected to the first flow extraction valve 161 and is used to control the operation of the first flow extraction valve 161; the controller 115 is communicatively connected to the electro-proportional control valve 112, the first electro-proportional pilot valve 113 and the second electro-proportional pilot valve 114. The controller 115 is used to send signals to the electro-proportional control valve 112 to control the displacement of the energy-saving motor 11, and is also used to send signals to the first electro-proportional pilot valve 113 and the second electro-proportional pilot valve 114 to control the operation of the differential regeneration valve 14 and the first flow extraction valve 161 respectively.

[0056] Furthermore, the energy-saving control system 10 also includes a first pressure sensor 116 and a second pressure sensor 117. The first pressure sensor 116 and the second pressure sensor 117 are used to detect the pressure of the oil intake / discharge valve assembly 17 and the accumulator 18, respectively. The third flow extraction valve 163, the first pressure sensor 116 and the second pressure sensor 117 are all connected to the controller 115. The controller 115 is also used to control the third flow extraction valve 163 to operate according to the pressure detected by the first pressure sensor 116 and the second pressure sensor 117, so as to divert the hydraulic oil from the outlet of the second flow extraction valve 162 to the return oil channel 13.

[0057] When the pressure value detected by the pressure sensor corresponding to the oil intake / discharge valve group 17 and the accumulator 18 reaches the corresponding setting, the controller 115 can automatically control the third flow extraction valve 163 to operate, so that the excess flow in the energy-saving circuit 15 is diverted from the third flow extraction valve 163 to the return oil channel 13.

[0058] In some embodiments, the energy-saving control system 10 further includes a second reversing valve 192, which is connected between the oil outlet of the energy-saving motor 11 and the oil intake / output valve group 17, so that the hydraulic oil output by the energy-saving motor 11 flows to the accumulator 18 through the oil intake / output valve group 17.

[0059] In this way, when it is necessary to release energy from the accumulator 18, in addition to the first and / or second energy release methods mentioned above, a third energy release method can also be used. As the third energy release method, the accumulator 18 releases the recovered high-pressure oil, which enters the oil inlet of the energy-saving motor 11 and flows through the oil outlet of the energy-saving motor 11 to the accumulator 18 via the second reversing valve 192 and the oil receiving and discharging valve group 17.

[0060] Understandably, when the pressure detected by the fourth pressure sensor 211 at the pump port of the first pump 21 and the fifth pressure sensor 221 at the pump port of the second pump 22 exceeds the corresponding set value, or when the output oil pressure of the first pump 21 and the second pump 22 is too high and the motor discharge oil cannot enter, the controller 115 controls the second reversing valve 192 to work, and the motor outlet flow can be recovered again to the oil receiving and discharging valve group 17, and then to the accumulator 18.

[0061] In some embodiments, the unloading oil circuit 12 is provided with a third directional valve 1101, and the energy-saving control system 10 also includes a solenoid valve 1102, which is connected to the third directional valve 1101 so that when the hydraulic oil pressure at the outlet of the energy-saving motor 11 exceeds a threshold, the third directional valve 1101 and the solenoid valve 1102 will unload the load.

[0062] In other words, if the motor outlet flow cannot enter the accumulator 18 at this time, that is, the pressure detected by the third pressure sensor 118 at the oil outlet of the energy-saving motor 11 exceeds the corresponding set value, the controller 115 sends a signal to the solenoid valve 1102 to unload through the third directional valve 1101.

[0063] In some embodiments, the energy-saving control system 10 further includes a pressure relief valve 1103 connected in parallel with the third reversing valve 1101. In this way, when the pressure at the oil outlet of the energy-saving motor 11 reaches the set pressure of the pressure relief valve 1103, the oil flow from the oil outlet of the energy-saving motor 11 flows through the pressure relief valve 1103 to the unloading oil passage 12 and then to the return oil passage 13.

[0064] In some embodiments, the oil inlet of the energy-saving motor 11 is connected to a one-way valve assembly 111, which is connected to the oil return channel 13 and the oil tank 119, so that the oil inlet of the energy-saving motor 11 can draw oil from the oil tank 119 or the oil return channel 13 through the one-way valve assembly 111.

[0065] In this way, the oil inlet of the energy-saving motor 11 draws oil from the oil tank 119 or the return oil channel 13 inside the valve through the one-way valve group 111, preventing the motor from drawing in cavitation.

[0066] The working process of the energy-saving control system 10 is explained in detail below:

[0067] After the vehicle starts, the controller 115 sends a signal to the electro-proportional control valve 112 to control the swashplate angle of the energy-saving motor 11 to swing to its minimum. The oil inlet of the energy-saving motor 11 draws oil from the oil tank 119 or the return oil passage 13 inside the valve through the one-way valve assembly 111 to prevent the motor from drawing in dry air. The system can select between normal and energy-saving modes (the signal is input to the controller 115 via the touch screen). When the excavator is in normal mode, the first directional valve assembly 19, including the first directional valve 191 and the second directional valve 192, the differential regeneration valve 14, the flow extraction valve assembly 16, and the oil recovery and discharge valve assembly 17 all have no action signals, and the energy-saving system is in the closed state. At this time, the second directional valve assembly 110, including the third directional valve 1101, the solenoid valve 1102, and the pressure relief valve 1103, is activated, unloading the oil outlet of the energy-saving motor 11, and the energy-saving motor 11 maintains minimum load standby operation.

[0068] When the excavator is in energy-saving mode, and the operator lowers the boom cylinder assembly 23, the first electro-proportional pilot valve 113 receives a signal from the controller 115, triggering the differential regeneration valve 14. This differentially connects the rod chamber and rodless chamber of the boom cylinder assembly 23, allowing them to communicate. On one hand, in the differential state, the rodless chamber of the boom cylinder assembly 23 supplies oil to the rod chamber. On the other hand, excess high-pressure oil from the rodless chamber of the boom cylinder assembly 23 enters the oil recovery / discharge valve assembly 17 through the flow extraction valve group 16, and finally enters the accumulator 18, completing the energy recovery process of the boom cylinder assembly 23's descent. The flow extraction valve assembly 16 is a dual differential pressure control flow control valve assembly. During energy recovery, on the one hand, the second flow extraction valve 162 acts as a downstream pressure compensation valve for the first flow extraction valve 161, stabilizing the pressure difference before and after the first flow extraction valve 161 to control the flow rate through the first flow extraction valve 161, thereby controlling the boom descent speed and the recovered high-pressure flow. On the other hand, the third flow extraction valve 163 acts as a differential pressure compensation valve between the inlet and outlet of the flow extraction valve assembly 16, ensuring that the outlet pressure of the second flow extraction valve 162 or the inlet pressure of the oil recovery / discharge valve assembly 17 does not exceed the set pressure stored in the accumulator 18. When the pressure values ​​detected by the pressure sensors corresponding to the oil recovery / discharge valve assembly 17 and the accumulator 18 reach the corresponding set values, the controller 115 can automatically control the third flow extraction valve 163 to operate, diverting excess flow in the energy-saving circuit 15 from the third flow extraction valve 163 to the return oil channel 13. Therefore, by controlling the opening degree of the first flow extraction valve 161 in the differential regeneration valve 14 and the flow extraction valve group 16, the speed of boom descent can be controlled while realizing energy recovery during boom descent, and the energy storage of accumulator 18 can be kept from overload. This ensures both the overall machine's operability and stable energy recovery.

[0069] During the energy release process, the cylinder pressure inside the accumulator 18 is collected by the second pressure sensor 117, and information on the current operating conditions is received. The controller 115 calculates and determines whether the recovered high-pressure oil in the accumulator 18 has reached the release condition. When the release condition is reached, the controller 115 sends a signal to the oil recovery and discharge valve group 17 to release and reuse the energy. When the accumulator 18 releases the recovered high-pressure oil, the high-pressure oil enters the oil inlet of the energy-saving motor 11, the motor runs, and the controller 115 sends a signal to the electro-proportional control valve 112 that controls the displacement adjustment of the energy-saving motor 11. The displacement of the energy-saving motor 11 increases, and at the same time, an action signal is sent to the first reversing valve 191 to supply oil to one of the output oil circuits of the first pump 21 and the second pump 22. When the pump port pressure of the first pump 21 and the second pump 22 exceeds the corresponding set value or the output circuit pressure of the first pump 21 and the second pump 22 is too high, and the motor cannot discharge oil, the second reversing valve 192 operates, and the motor outlet flow can be recovered again to the oil recovery and discharge valve group 17, and then to the accumulator 18. If the motor outlet flow cannot enter the accumulator 18 at this time, that is, the oil outlet pressure of the energy-saving motor 11 exceeds the corresponding set value, then the controller 115 sends a signal to the solenoid valve 1102 to unload through the third directional valve 1101.

[0070] When the high-pressure oil released by the accumulator 18 gradually decreases to insufficient pressure during the release process, and the outlet load pressure of the energy-saving motor 11 is too high, the main shafts of the first pump 21 and the second pump 22 rotate with the motor, and the energy-saving motor 11 changes to pump mode. By absorbing the torque of the engine 25, it is converted into hydraulic pump mode to output hydraulic energy, which is directly supplied to the output circuits of the first pump 21 and the second pump 22. The one-way valve group 111 at the oil inlet of the energy-saving motor 11 draws oil from the return oil channel 13 or the oil tank 119 to avoid cavitation when the energy-saving motor 11 switches to hydraulic pump mode.

[0071] In summary, by setting up the aforementioned energy-saving control system 10, the excavator can switch between normal and energy-saving modes, and can also operate in energy-saving mode for extended periods, maximizing the recovery and utilization of boom energy. The recovered energy can be used to drive the energy-saving motor 11 to output torque to the engine 25 in reverse, or directly to supply oil to the hydraulic system, or it can be re-stored in the accumulator 18, achieving energy-saving effects throughout the motor's operation. This ensures that the recovered hydraulic energy is utilized to the maximum extent, reducing the power output of the engine 25, reducing hydraulic system heat generation, lowering energy consumption, and improving operational efficiency.

[0072] The hydraulic control device for an excavator provided in this application includes an excavator hydraulic control system 20. The excavator hydraulic control system 20 includes a hydraulic pump group, a boom cylinder assembly 23, and a multi-way valve 24. The hydraulic pump group includes a first pump 21 and a second pump 22 connected to each other. The boom cylinder assembly 23 includes at least two boom cylinders. The multi-way valve 24 is connected to the output oil circuit of the hydraulic pump group and the rodless chamber oil circuit and the rod chamber oil circuit of the boom cylinder assembly 23. Specifically, the multi-way valve 24 includes a boom confluence valve 241 and a boom control valve 242. The flow rate of the first pump 21 can enter the rodless chamber of the boom cylinder assembly 23 under the control of the boom confluence valve 241, and the flow rate of the second pump 22 can enter the rodless chamber of the boom cylinder assembly 23 under the control of the boom control valve 242, so as to control the lifting action of the boom cylinder assembly 23.

[0073] In addition, the excavator hydraulic control device also includes the energy-saving control system 10 described in the above specific embodiments. The energy-saving motor 11 of the energy-saving control system 10 is connected in series at the shaft end of the hydraulic pump group. The differential regeneration valve 14 of the energy-saving control system 10 is connected between the rodless chamber oil circuit and the rod chamber oil circuit of the boom cylinder assembly 23. The energy-saving circuit 15 of the energy-saving control system 10 is connected to the rodless chamber oil circuit of the boom cylinder assembly 23. The first directional valve 191 of the energy-saving control system 10 is connected between the oil outlet of the energy-saving motor 11 and the output oil circuit of the hydraulic pump group.

[0074] It should be noted that in this specification, relational terms such as first and second are used only to distinguish one entity from several other entities, and do not necessarily require or imply any such actual relationship or order between these entities.

[0075] The energy-saving control system and excavator hydraulic control device provided in this application have been described in detail above. Specific examples have been used to illustrate the principles and implementation methods of this application. The descriptions of the embodiments above are only for the purpose of helping to understand the solution and core ideas of this application. It should be noted that those skilled in the art can make several improvements and modifications to this application without departing from the principles of this application, and these improvements and modifications also fall within the protection scope of this application.

Claims

1. An energy-saving control system for an excavator hydraulic control system, characterized in that, include: An energy-saving motor is used to connect to the shaft end of the hydraulic pump unit of the excavator's hydraulic control system. The oil outlet of the energy-saving motor is connected to the return oil channel through an unloading oil circuit. A differential regeneration valve is used to connect the rodless chamber oil passage and the rod chamber oil passage of the boom cylinder assembly in the hydraulic control system of an excavator. An energy-saving circuit is used to connect to the rodless chamber oil circuit of the boom cylinder assembly in the excavator's hydraulic control system. The energy-saving circuit includes a flow extraction valve group, a take-up and release valve group, and an accumulator. This allows the hydraulic oil in the rodless chamber oil circuit of the boom cylinder assembly to flow into the accumulator via the flow extraction valve group and the take-up and release valve group. The take-up and release valve group is connected to the oil inlet of the energy-saving motor; and / or The first reversing valve is used to connect between the oil outlet of the energy-saving motor and the output oil circuit of the hydraulic pump group of the excavator hydraulic control system, so that the hydraulic oil output by the energy-saving motor flows to the output oil circuit of the hydraulic pump group. The flow extraction valve assembly includes a first flow extraction valve and a second flow extraction valve. The second flow extraction valve is located between the first flow extraction valve and the oil intake / discharge valve assembly. The first pilot oil passage of the second flow extraction valve is connected to the oil inlet of the first flow extraction valve, and the second pilot oil passage of the second flow extraction valve is connected to the oil outlet of the first flow extraction valve, so that the pressure difference between the oil inlet and the oil outlet of the first flow extraction valve is maintained at a set value.

2. The energy-saving control system as described in claim 1, characterized in that, The flow extraction valve assembly further includes a third flow extraction valve. The first pilot oil passage of the third flow extraction valve is connected to the inlet of the first flow extraction valve, and the second pilot oil passage of the third flow extraction valve is connected to the outlet of the second flow extraction valve. The third flow extraction valve is also connected to the return oil channel so that when the pressure difference between the inlet of the first flow extraction valve and the outlet of the second flow extraction valve meets a preset condition, the hydraulic oil at the outlet of the second flow extraction valve is diverted to the return oil channel.

3. The energy-saving control system as described in claim 2, characterized in that, The energy-saving control system also includes: An electro-proportional control valve is used to control the displacement of the energy-saving motor; A first electro-proportional pilot valve is used to control the operation of the differential regeneration valve; The second electro-proportional pilot valve is used to control the operation of the first flow extraction valve. The controller is communicatively connected to the electro-proportional control valve, the first electro-proportional pilot valve, and the second electro-proportional pilot valve. It is used to send signals to the electro-proportional control valve to control the displacement of the energy-saving motor, and also to send signals to the first electro-proportional pilot valve and the second electro-proportional pilot valve to control the operation of the differential regeneration valve and the first flow extraction valve, respectively.

4. The energy-saving control system as described in claim 3, characterized in that, The energy-saving control system further includes a first pressure sensor and a second pressure sensor. The first pressure sensor and the second pressure sensor are used to detect the pressure of the oil intake and exhaust valve group and the accumulator, respectively. The third flow extraction valve, the first pressure sensor and the second pressure sensor are all communicatively connected to the controller. The controller is also used to control the third flow extraction valve to operate according to the pressure detected by the first pressure sensor and the second pressure sensor, so as to divert the hydraulic oil at the outlet of the second flow extraction valve to the return oil channel.

5. The energy-saving control system as described in claim 1, characterized in that, The energy-saving control system also includes a second reversing valve, which is connected between the oil outlet of the energy-saving motor and the oil intake / discharge valve group, so that the hydraulic oil output by the energy-saving motor flows to the accumulator through the oil intake / discharge valve group.

6. The energy-saving control system as described in claim 5, characterized in that, The unloading oil circuit is equipped with a third directional valve, and the energy-saving control system also includes a solenoid valve. The solenoid valve is connected to the third directional valve so that when the hydraulic oil pressure at the outlet of the energy-saving motor exceeds a threshold, the third directional valve and the solenoid valve will unload the load.

7. The energy-saving control system as described in claim 6, characterized in that, The energy-saving control system also includes a pressure relief valve connected in parallel with the third reversing valve.

8. The energy-saving control system as described in claim 1, characterized in that, The oil inlet of the energy-saving motor is connected to a one-way valve assembly, which is connected to the oil return channel and the oil tank, so that the oil inlet of the energy-saving motor can draw oil from the oil tank or the oil return channel through the one-way valve assembly.

9. A hydraulic control device for an excavator, comprising an excavator hydraulic control system, the excavator hydraulic control system comprising a hydraulic pump assembly, a boom cylinder assembly, and a multi-way valve, the multi-way valve being connected to the output oil circuit of the hydraulic pump assembly and the rodless chamber oil circuit and the rod chamber oil circuit of the boom cylinder assembly, to control the movement of the boom cylinder assembly, characterized in that, It also includes an energy-saving control system as described in any one of claims 1-8, wherein the energy-saving motor of the energy-saving control system is connected to the shaft end of the hydraulic pump group, the differential regeneration valve of the energy-saving control system is connected between the rodless chamber oil circuit and the rod chamber oil circuit of the boom cylinder assembly, the energy-saving circuit of the energy-saving control system is connected to the rodless chamber oil circuit of the boom cylinder assembly, and the first directional valve of the energy-saving control system is connected between the oil outlet of the energy-saving motor and the output oil circuit of the hydraulic pump group.

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