Driving and recycling integrated hydraulic system

Abstract

The invention relates to the technical field of hydraulic energy-saving control, in particular to a driving and recycling integrated hydraulic system which comprises a plurality of executive components and a driving loop device controlling the executive components, the executive components are hydraulic cylinders or / and rotary motors, the driving loop device is provided with a motor, the motor is provided with drivers, and a controller is connected with the drivers. The motor is connected with the two hydraulic pumps / motors in a driving mode, oil outlets of the two hydraulic pumps / motors are connected with the execution element, oil inlets of the two hydraulic pumps / motors are connected with the oil tank, and a spring-free one-way valve and a spring one-way valve are arranged on oil ways where the oil inlets of the two hydraulic pumps / motors are connected with the oil tank respectively. An inlet of the springless one-way valve is connected with the oil tank, an outlet of the springless one-way valve is connected with the oil tank, the reversing valves are parallelly arranged on a loop between an inlet and an outlet of the hydraulic pump / motor, the springless one-way valve and the reversing valves are parallelly arranged on a loop between the inlet and the outlet of the hydraulic pump / motor, and the controller controls and is connected with the two reversing valves.

Description

Technical Field

[0001] The invention belongs to the technical field of energy-saving hydraulic control, and particularly relates to a hydraulic system integrating driving and recovery. Background Art

[0002] For a traditional hydraulic excavator, only about 20% of the energy output by the engine is utilized by actuators such as hydraulic cylinders and hydraulic motors of the working device, traveling system, and slewing system, while most of the energy is dissipated in the throttle orifice in the form of heat during the lowering of the boom and the slewing braking process. The hydraulic systems of excavators have generally adopted technologies such as load-sensitive systems, positive and negative flow and independent control systems for load ports. However, these technologies do not directly and effectively solve the problem of the dissipation of boom potential energy and slewing braking energy in the throttle orifice. However, the electrification of excavators provides convenient conditions for the application of the electrical energy recovery method. The electrical recovery method converts the wasted hydraulic energy of the working device into electrical energy for storage through a hydraulic motor or a hydraulic pump / motor - generator. Considering the working conditions of the excavator during operation, they are all throttle losses generated by valve-controlled cylinders and gravitational potential energy generated by negative loads of the load. Therefore, a new hydraulic system recovery device is proposed to recover gravitational potential energy in order to save energy and reduce emissions. Summary of the Invention

[0003] The electrification of excavators provides convenient conditions for the application of the electrical energy recovery method. The electrical recovery method converts the gravitational potential energy of the working device into electrical energy for storage through a hydraulic motor or a hydraulic pump / motor - generator. Aiming at the deficiencies of the existing hydraulic systems of excavators and lifting devices, such as low energy efficiency, large battery installation capacity, and short battery life caused by the valve-controlled hydraulic cylinder system, the invention proposes a new hydraulic system integrating driving and recovery. By configuring the displacements of the hydraulic cylinder and two hydraulic pump / motors, flow matching and throttle-loss-free driving of the hydraulic actuators of the working device are achieved. The hydraulic power source of this device uses an electric motor, which provides convenient conditions for the application of the electrical energy recovery method. The electrical recovery method converts the gravitational potential energy of the working device into electrical energy for storage.

[0004] To further study a new hydraulic system integrating driving and recovery and apply it to the recovery of the boom potential energy of an excavator. Aiming at the deficiencies of the existing electric excavators using a multi-way valve control system, such as low energy efficiency, large battery installation capacity, and short battery life, the invention improves the original hydraulic system as follows Figure 1 as shown.

[0005] The present invention adopts the following technical solutions: A hydraulic system integrating driving and recovery, including a plurality of actuators and a driving circuit device for controlling them. The actuators are hydraulic cylinders and / or rotary motors. The driving circuit device is respectively provided with motors, and each motor is respectively provided with a driver. A controller is provided and connected to each driver respectively. The driving circuit device includes control circuits respectively connected to the actuators. The control circuit components specifically include: motors, two hydraulic pump / motors, non-spring one-way valves, spring one-way valves, and two reversing valves. Among them, the motors are drivingly connected to the two hydraulic pump / motors. The oil outlets of the two hydraulic pump / motors are respectively connected to the actuators, and the oil inlets of the two hydraulic pump / motors are respectively connected to the fuel tank. Non-spring one-way valves and spring one-way valves are respectively arranged on the oil paths connecting the oil inlets of the two hydraulic pump / motors to the fuel tank. The inlet of the non-spring one-way valve is connected to the fuel tank, and the outlet of the spring one-way valve is connected to the fuel tank. Reversing valves are arranged in parallel in the circuit between the inlet and outlet of the hydraulic pump / motor. Non-spring one-way valves and reversing valves are arranged in parallel in the circuit between the inlet and outlet of the hydraulic pump / motor connecting the rod chamber of the hydraulic cylinder, or non-spring one-way valves and reversing valves are arranged in parallel in the circuit between the inlet and outlet of the hydraulic pump / motor of the rotary motor. The outlet of the non-spring one-way valve is connected to the inlet of the spring one-way valve. The outlets of the two overflow valves are connected to the fuel tank. The controller respectively controls and connects the two reversing valves.

[0006] The reversing valve is a proportional flow control valve and / or a proportional reversing valve.

[0007] The control circuit components further include: overflow valves and pressure sensors. The outlets of the hydraulic pump / motors are respectively connected to pressure sensors and overflow valves. The controller is control-connected to the pressure sensors.

[0008] The actuators are respectively: the boom cylinder, the stick cylinder, the bucket cylinder, and the swing motor. Four drive circuit devices are respectively provided corresponding to the four actuators: namely, drive circuit device one, drive circuit device two, drive circuit device three, and drive circuit device four. The four drive circuit devices are respectively provided with: motor one, motor two, motor three, and motor four. Drive circuit device one includes: a rod chamber control circuit respectively connected to the rod chamber of the boom cylinder and a rodless chamber control circuit connected to the rodless chamber of the boom cylinder. The control circuit components specifically include: motor one, hydraulic pump / motor one, hydraulic pump / motor two, non-spring check valve, spring check valve, first proportional flow control valve, second proportional flow control valve, overflow valve, and pressure sensor. Among them, motor one is drivingly connected to hydraulic pump / motor one and hydraulic pump / motor two. The oil outlet of hydraulic pump / motor one is connected to the rodless chamber of the boom cylinder, and the oil outlet of hydraulic pump / motor two is connected to the rod chamber of the boom cylinder. The oil inlets of hydraulic pump / motor one and hydraulic pump / motor two are respectively connected to the fuel tank. Non-spring check valves and spring check valves are respectively provided on the oil paths where the oil inlets of hydraulic pump / motor one and hydraulic pump / motor two are connected to the fuel tank. The inlet of the non-spring check valve is connected to the fuel tank, and the outlet of the spring check valve is connected to the fuel tank. A first proportional flow control valve is arranged in parallel in the circuit between the inlet and outlet of hydraulic pump / motor one. A non-spring check valve and a second proportional flow control valve are arranged in parallel in the circuit between the inlet and outlet of hydraulic pump / motor two. The outlet of the non-spring check valve is connected to the inlet of the spring check valve. Pressure sensors and overflow valves are respectively connected to the outlets of hydraulic pump / motor one and hydraulic pump / motor two. The outlets of the two overflow valves are connected to the fuel tank. The controller is respectively controlling and connecting the first proportional flow control valve, the second proportional flow control valve, and the pressure sensor.

[0009] A displacement sensor is provided on the boom cylinder, and the controller is controlling and connecting the displacement sensor.

[0010] The non-spring check valve has zero opening pressure, and the spring check valve has an opening pressure.

[0011] The drive circuit device four includes: a control circuit respectively connected to the inlet and outlet of the slewing motor. The control circuit components specifically include: motor four, hydraulic pump / motor seven, hydraulic pump motor eight, non-spring check valve, spring check valve, seventh proportional flow control valve, eighth proportional flow control valve, relief valve, pressure sensor, second non-spring check valve. Among them, motor four is drivingly connected to hydraulic pump / motor seven and hydraulic pump / motor eight. The oil outlets of hydraulic pump / motor seven and hydraulic pump / motor eight are respectively connected to the slewing motor, and the oil inlets of hydraulic pump / motor seven and hydraulic pump / motor eight are respectively connected to the fuel tank. A non-spring check valve and a spring check valve are respectively arranged on the oil paths connecting the oil inlets of hydraulic pump / motor seven and hydraulic pump / motor eight to the fuel tank. The inlet of the non-spring check valve is connected to the fuel tank, and the outlet of the spring check valve is connected to the fuel tank. A seventh proportional flow control valve and a second non-spring check valve are arranged in parallel in the circuit between the inlet and outlet of hydraulic pump / motor seven. The outlet of the second non-spring check valve is connected to the inlet of the spring check valve. A non-spring check valve and an eighth proportional flow control valve are arranged in parallel in the circuit between the inlet and outlet of hydraulic pump / motor eight. The outlet of the non-spring check valve is connected to the inlet of the spring check valve. Pressure sensors and relief valves are respectively connected to the outlets of hydraulic pump / motor seven and hydraulic pump / motor eight. The outlets of the two relief valves are connected to the fuel tank. The controller is respectively control-connected to the seventh proportional flow control valve, the eighth proportional flow control valve, and the pressure sensor.

[0012] Compared with the prior art, the present invention can achieve the following technical effects: The power source and energy recovery part of this system are integrated, that is, the motor coaxially drives the double hydraulic pump / motors. During the lowering process of the working device, the oil in the rodless cavity of the oil cylinder drives the hydraulic pump / motor to rotate, driving the coaxial motor to generate electricity and enabling storage. This hydraulic power pack system can not only be applied to double-cylinder synchronization or multi-cylinder synchronization and multi-cylinder coordinated control, but also be applied to the hydraulic system of excavators. It not only has good synchronization performance but also has significant energy-saving effects.

[0013] 2. In the present invention, proportional flow control valves are installed at the inlet and outlet of the two hydraulic pump / motors to prevent cavitation caused by the flow rate of the hydraulic pump / motor not keeping up during the movement of the oil cylinder. For example, when the boom of the excavator descends, the proportional flow control valve opens, making the pressure difference between the inlet and outlet of the hydraulic pump / motor basically zero, improving the efficiency of converting the gravitational potential energy of the boom into electrical energy. This system has a significant recovery effect.

[0014] 3. The present invention provides a new type of excavator slewing hydraulic system with integrated drive and recovery. Among them, for the slewing section hydraulic system, precise control of the rotation speed of the slewing motor is achieved by adjusting the speed of the motor. The control technical means are simple and easy to achieve intelligent control.

[0015] 4. During the starting process of the excavator's slewing, the starting impact can be reduced by adjusting the motor speed and the electrical signal of the proportional flow control valve, avoiding overflow loss.

[0016] 5. Adopting a hydraulic system that combines driving and energy recovery can improve reliability while saving costs. Moreover, the energy recovered during braking is stored in the super capacitor and used during the starting process. 6. During the starting and braking processes of the excavator, the overflow valve is in the closed state, that is, there is no overflow loss, eliminating the noise generated when the overflow valve opens and closes.

[0017] The system of the present invention has no throttling elements. Firstly, the pressure loss is small and the heat generation is small, so no cooling device is required. At the same time, the throttling loss and overflow loss of the system are avoided, and the system efficiency is relatively high. It can also convert energy such as the gravitational potential energy of the load into electrical energy and store it in the power supply device for reuse, saving energy. Secondly, it can also achieve the integration of driving and energy recovery. While reducing the energy recovery device, it can achieve the efficient utilization of energy, reduce the dependence on traditional energy, and at the same time can also reduce carbon emissions and environmental pollution, meeting the concept of sustainable development. The research and development and application of this technology will have a positive impact on industries such as excavators, promoting the development of the field of mechanical engineering towards a more environmentally friendly and intelligent direction. Brief Description of the Drawings

[0018] Figure 1 is the hydraulic schematic diagram of the present invention; Figure 2 is the diagram of the non-uniform speed characteristic of the motor slewing work of the present invention; Figure 3 is the diagram of the uniform speed characteristic of the motor slewing work of the present invention.

[0019] Among them, 101 - Motor 1, 102 - Motor 2, 103 - Motor 3, 104 - Motor 4, 201 - Hydraulic Pump / Motor 1, 301 - Hydraulic Pump / Motor 2, 4 - Non-spring check valve, 5 - Spring check valve, 601 - First proportional flow control valve, 602 - Second proportional flow control valve, 7 - Overflow valve, 8 - Pressure sensor, 202 - Hydraulic Pump / Motor 3, 302 - Hydraulic Pump / Motor 4, 603 - Third proportional flow control valve, 604 - Fourth proportional flow control valve, 203 - Hydraulic Pump / Motor 5, 303 - Hydraulic Pump / Motor 6, 605 - Fifth proportional flow control valve, 606 - Sixth proportional flow control valve, 204 - Hydraulic Pump / Motor 7, 304 - Hydraulic Pump / Motor 8, 607 - Seventh proportional flow control valve, 608 - Eighth proportional flow control valve, 110 - Controller, 1201 - Boom cylinder, 1202 - Arm cylinder, 1203 - Bucket cylinder, 130 - Slewing motor, 140 - Displacement sensor. Detailed Embodiment

[0020] Such asFigure 1 , a driving and recycling integrated hydraulic system, comprising: four actuators, namely: boom cylinder 1201, stick cylinder 1202, bucket cylinder 1203, slewing motor 130. Corresponding to the four actuators, four driving circuit devices are respectively provided: driving circuit device one, driving circuit device two, driving circuit device three, driving circuit device four. A displacement sensor 140 is provided on the boom cylinder 1201. The four driving circuit devices are respectively provided with: motor one 101, motor two 102, motor three 103, motor four 104. Each motor is respectively provided with a driver. A controller 110 is provided and connected to each driver and the displacement sensor 140 respectively. The driving circuit device one includes: a rod chamber control circuit respectively connected to the rod chamber of the boom cylinder 1201 and a rodless chamber control circuit connected to the rodless chamber of the boom cylinder 1201. The control circuit components specifically include: motor one 101, hydraulic pump / motor one 201, hydraulic pump / motor two 301, non-spring check valve 4, spring check valve 5, first proportional flow control valve 601, second proportional flow control valve 602, overflow valve 7, pressure sensor 8; Among them, motor one 101 is drivingly connected to hydraulic pump / motor one 201 and hydraulic pump / motor two 301. The oil outlet of hydraulic pump / motor one 201 is connected to the rodless chamber of the boom cylinder 1201. The oil outlet of hydraulic pump / motor two 301 is connected to the rod chamber of the boom cylinder 1201. The oil inlets of hydraulic pump / motor one 201 and hydraulic pump / motor two 301 are respectively connected to the fuel tank. Non-spring check valves 4 and spring check valves 5 are respectively provided on the oil paths connecting the oil inlets of hydraulic pump / motor one 201 and hydraulic pump / motor two 301 to the fuel tank. The inlet of non-spring check valve 4 is connected to the fuel tank, and the outlet of spring check valve 5 is connected to the fuel tank. A first proportional flow control valve 601 is provided in parallel in the circuit between the inlet and outlet of hydraulic pump / motor one 201. A non-spring check valve 4 and a second proportional flow control valve 604 are provided in parallel in the circuit between the inlet and outlet of hydraulic pump / motor two 301. The outlet of non-spring check valve 4 is connected to the inlet of spring check valve 5. The non-spring check valve 4 has a zero opening pressure, and the spring check valve 5 has an opening pressure. The outlets of hydraulic pump / motor one 201 and hydraulic pump / motor two 301 are respectively connected to a pressure sensor 8 and an overflow valve 7. The outlets of the two overflow valves 7 are connected to the fuel tank. The controller 110 is respectively connected to control the first proportional flow control valve 601, the second proportional flow control valve 602, and the pressure sensor 8.

[0021] The driving circuit device two includes: a rod chamber control circuit respectively connected to the rod chamber of the stick cylinder 1202 and a rodless chamber control circuit connected to the rodless chamber of the stick cylinder 1202. The control circuit components specifically include: motor two 102, hydraulic pump / motor three 202, hydraulic pump / motor four 302, non-spring check valve 4, spring check valve 5, third proportional flow control valve 603, fourth proportional flow control valve 604, overflow valve 7, pressure sensor 8; Among them, the second motor 102 is drivingly connected to the third hydraulic pump / motor 202 and the fourth hydraulic pump / motor 302. The oil outlet of the third hydraulic pump / motor 202 is connected to the rodless cavity of the stick cylinder 1202, and the oil outlet of the fourth hydraulic pump / motor 302 is connected to the rod cavity of the stick cylinder 1202. The oil inlets of the third hydraulic pump / motor 202 and the fourth hydraulic pump / motor 302 are respectively connected to the fuel tank. Non-spring one-way valves 4 and spring-loaded one-way valves 5 are respectively arranged on the oil paths connecting the oil inlets of the third hydraulic pump / motor 202 and the fourth hydraulic pump / motor 302 to the fuel tank. The inlet of the non-spring one-way valve 4 is connected to the fuel tank, and the outlet of the spring-loaded one-way valve 5 is connected to the fuel tank. A third proportional flow control valve 603 is arranged in parallel in the circuit between the inlet and outlet of the third hydraulic pump / motor 202. A non-spring one-way valve 4 and a fourth proportional flow control valve 604 are arranged in parallel in the circuit between the inlet and outlet of the fourth hydraulic pump / motor 302. The outlet of the non-spring one-way valve 4 is connected to the inlet of the spring-loaded one-way valve 5. The non-spring one-way valve 4 has a zero opening pressure, and the spring-loaded one-way valve 5 has an opening pressure. Pressure sensors 8 and overflow valves 7 are respectively connected to the outlets of the third hydraulic pump / motor 202 and the fourth hydraulic pump / motor 302. The outlets of the two overflow valves 7 are connected to the fuel tank. The controller 110 is respectively connected to control the third proportional flow control valve 603, the fourth proportional flow control valve 604, and the pressure sensor 8.

[0022] The third driving circuit device includes a rod cavity control circuit respectively connected to the rod cavity of the bucket cylinder 1203 and a rodless cavity control circuit connected to the rodless cavity of the bucket cylinder 1203. The control circuit components specifically include: the third motor 103, the fifth hydraulic pump / motor 203, the sixth hydraulic pump / motor 303, the non-spring one-way valve 4, the spring-loaded one-way valve 5, the fifth proportional flow control valve 605, the sixth proportional flow control valve 606, the overflow valve 7, and the pressure sensor 8; Among them, the motor three 103 is drivingly connected to the hydraulic pump / motor five 203 and the hydraulic pump / motor six 303. The outlet of the hydraulic pump / motor five 203 is connected to the rodless cavity of the bucket cylinder 1203, and the outlet of the hydraulic pump / motor six 303 is connected to the rod cavity of the bucket cylinder 1203. The inlets of the hydraulic pump / motor five 203 and the hydraulic pump / motor six 303 are respectively connected to the fuel tank. Non-spring check valves 4 and spring check valves 5 are respectively arranged on the oil paths connecting the inlets of the hydraulic pump / motor five 203 and the hydraulic pump / motor six 303 to the fuel tank. The inlet of the non-spring check valve 4 is connected to the fuel tank, and the outlet of the spring check valve 5 is connected to the fuel tank. A fifth proportional flow control valve 605 is arranged in parallel in the circuit between the inlet and outlet of the hydraulic pump / motor five 203. A non-spring check valve 4 and a sixth proportional flow control valve 606 are arranged in parallel in the circuit between the inlet and outlet of the hydraulic pump / motor six 303. The outlet of the non-spring check valve 4 is connected to the inlet of the spring check valve 5. The non-spring check valve 4 has a zero opening pressure, and the spring check valve 5 has an opening pressure. Pressure sensors 8 and relief valves 7 are respectively connected to the outlets of the hydraulic pump / motor five 203 and the hydraulic pump / motor six 303. The outlets of the two relief valves 7 are connected to the fuel tank. The controller 110 is respectively controllably connected to the fifth proportional flow control valve 605, the sixth proportional flow control valve 606, and the pressure sensor 8.

[0023] The drive circuit device four includes: a control circuit respectively connected to the inlet and outlet of the swing motor 130. The control circuit components specifically include: the motor four 104, the hydraulic pump / motor seven 204, the hydraulic pump motor eight 304, the non-spring check valve 4, the spring check valve 5, the seventh proportional flow control valve 607, the eighth proportional flow control valve 608, the relief valve 7, the pressure sensor 8, and the second non-spring check valve 4011; Among them, the motor four 104 is drivingly connected to the hydraulic pump / motor seven 204 and the hydraulic pump / motor eight 304. The oil outlets of the hydraulic pump / motor seven 204 and the hydraulic pump / motor eight 304 are respectively connected to the slewing motor 130. The oil inlets of the hydraulic pump / motor seven 204 and the hydraulic pump / motor eight 304 are respectively connected to the fuel tank. Non-spring check valves 4 and spring check valves 5 are respectively arranged on the oil paths where the oil inlets of the hydraulic pump / motor seven 204 and the hydraulic pump / motor eight 304 are connected to the fuel tank. The inlet of the non-spring check valve 4 is connected to the fuel tank, and the outlet of the spring check valve 5 is connected to the fuel tank. A seventh proportional flow control valve 607 and a second non-spring check valve 4011 are arranged in parallel in the circuit between the inlet and outlet of the hydraulic pump / motor seven 204. The outlet of the second non-spring check valve 4011 is connected to the inlet of the spring check valve 5. A non-spring check valve 4 and an eighth proportional flow control valve 608 are arranged in parallel in the circuit between the inlet and outlet of the hydraulic pump / motor eight 304. The outlet of the non-spring check valve 4 is connected to the inlet of the spring check valve 5. The non-spring check valve 4 has a zero opening pressure, and the spring check valve 5 has an opening pressure. Pressure sensors 8 and relief valves 7 are respectively connected to the outlets of the hydraulic pump / motor seven 204 and the hydraulic pump / motor eight 304. The outlets of the two relief valves 7 are connected to the fuel tank. The controller 110 is respectively controlling and connecting the seventh proportional flow control valve 607, the eighth proportional flow control valve 608, and the pressure sensor 8.

[0024] The working mode is as follows: One, boom potential energy recovery 1. Boom rising During the boom rising process, in the case of heavy load, the speed of the oil cylinder will be greatly reduced, and some overflow losses will occur in the hydraulic system of traditional excavators at this time. The present invention adopts a variable-speed motor-101. The controller 110 collects the displacement of the boom cylinder 1201 and the pressures of its two chambers through the displacement sensor 140 and the pressure sensor 8 respectively, and adjusts the speed of the motor-101 through the controller 110 to match the flow rate under the heavy-load condition, so as to meet the power required for the boom cylinder 1201 to drive the load; by transmitting the pressure collected by the pressure sensor 8 to the controller 110, enabling it to issue a signal command, on the one hand, the second proportional flow control valve 602 is energized and opened, and the first proportional flow control valve 601 is not opened, reducing the pressure difference between the inlet and outlet ports of the hydraulic pump / motor two 301 to be basically zero, reducing the power required to drive the hydraulic pump / motor two 301; on the other hand, the displacement sensor 140 and the pressure sensor 8 respectively collect the moving displacement of the boom cylinder 1201 and the pressures of the two chambers of the oil cylinder. By adopting a pressure-position compound control algorithm, through the controller 110 to issue an instruction, the power output by the hydraulic pump 201 is matched with the load. Through the controller 110 to issue an instruction, the speed of the motor-101 is adjusted to match the flow rate required by the load at this time, so as to reduce the electric energy required for the motor-101 to drive the hydraulic pump / motor, reduce the driving power of the motor, and achieve the purpose of reducing the installed power of the motor and saving energy.

[0025] 2. Boom lowering During the boom lowering process, when the first proportional flow control valve 601 and the second proportional flow control valve 602 are not opened, the hydraulic oil of the hydraulic pump / motor two 301 enters the rod chamber of the boom cylinder 1201. The oil in the non-rod chamber of the hydraulic cylinder pushes the motor-101 to rotate and generate electricity through the hydraulic pump / motor one 201. At this time, the gravitational potential energy of the boom is converted into electric energy for storage. However, the hydraulic pump / motor one 201 needs to drive both the motor-101 and the hydraulic pump / motor two 301 at the same time, resulting in a part of the energy loss for driving the hydraulic pump / motor one 201, and the boom potential energy cannot be completely converted into electric energy. When the controller 110 issues an instruction to open the second proportional flow control valve 602, the pressure difference between the inlet and outlet ports of the hydraulic pump / motor two 301 is basically zero. Because the oil at this time enters the rod chamber of the boom cylinder 1201 through the non-spring check valve 4 and the second proportional flow control valve 602, the rod chamber of the boom cylinder 1201 is connected to the fuel tank, and its pressure is basically zero, making the power required to drive the hydraulic pump / motor two 301 basically zero, indirectly increasing the power of the hydraulic pump / motor one 201 to drive the motor-101, improving the power generation power of the motor, and achieving the purpose of completely recovering the boom potential energy.

[0026] II. Rotary braking recovery 1. Working principle As Figures 1 - 3, the motion state during one working cycle of the slewing motor 130 is generally start-up acceleration, constant speed, braking deceleration, reverse start-up acceleration, constant speed, and braking deceleration. Figures 2 and 3 respectively show the slewing characteristic processes without and with constant speed, as shown below. Figure 2 It can be seen that it is first in the forward start state, then braking deceleration; then reverse start, and finally braking deceleration. Figure 3 It can be seen that it is first in the forward start state, then slewing at a constant speed, and then braking deceleration; then reverse start-up acceleration, slewing at a constant speed, and finally braking deceleration. Figures 2 - 3 It can be observed that during the full-bucket slewing process, the moment of inertia is relatively large, so the required energy is also relatively large. In addition, the acceleration (slope) during braking is greater than that during start-up. At the same time, it can be known that one working cycle of the excavator slewing platform is symmetric, so the following analyzes it with half a cycle as an example.

[0027] 2. Start-up stage The excavator slewing platform has different speed requirements under different working conditions. When the space is narrow, it needs to start slowly; when improving the operation efficiency, it needs to start quickly. Therefore, the present invention considers these two working conditions respectively: slow start and fast start.

[0028] During the process of the excavator slewing platform slowly rotating to the right to start, the variable-speed motor four 104 coaxially drives the hydraulic pump / motor. At this time, the hydraulic pump / motor seven 204 discharges oil to the oil suction port of the slewing motor 130, and the oil fluid at the oil outlet of the slewing motor 130 is discharged back to the fuel tank through the hydraulic pump / motor eight 304. The controller 110 issues an instruction through the pressures at the inlet and outlet ports of the slewing motor 130 collected by the two pressure sensors 8, so that the motor four 104 is in a low-speed state, matching the flow rate under the full-load rotation working condition to meet the power required for the slewing motor 130 to drive the load. During the above process, due to the presence of the spring check valve 5, a certain back pressure is generated in the oil return circuit of the slewing motor 130. If the eighth proportional flow control valve 608 is opened through the controller 110 to make the pressure difference between the inlet and outlet ports of the hydraulic pump / motor eight 304 basically zero, the power required to drive the hydraulic pump / motor eight 304 is reduced, the driving power of the motor is reduced, and the installed power of the motor is reduced and the energy saving is improved.

[0029] During the process of the rapid right rotation start of the excavator slewing platform, the motor four 104 coaxially drives the hydraulic pump / motor. At this time, the hydraulic pump / motor seven 204 discharges oil to the suction port of the slewing motor 130, and the oil from the outlet port of the slewing motor 130 is discharged back to the fuel tank through the hydraulic pump / motor eight 304. The controller 110 issues an instruction based on the pressures at the inlet and outlet ports of the slewing motor 130 collected by the pressure sensor 8, causing the motor four 104 to operate at a high rotational speed to match the flow rate under the full-load rotation condition to meet the power required to drive the load of the slewing motor 130. During the above process, if the eighth proportional flow control valve 608 is opened through the controller 110 to make the pressure difference between the inlet and outlet ports of the hydraulic pump / motor eight 304 basically zero, the power required to drive the hydraulic pump / motor eight 304 is reduced, the driving power of the motor is decreased, achieving the purpose of reducing the installed power of the motor and saving energy. If during the above process, the seventh proportional flow control valve 607 is not opened by a certain opening through the controller 110, starting shock will still occur. Therefore, when the seventh proportional flow control valve 607 is opened by a certain opening through the controller 110 to form a certain pressure difference between the inlet and outlet ports of the valve, the hydraulic oil with starting shock flows through the seventh proportional flow control valve 607 to the inlet port of the hydraulic pump / motor seven 204. Under the action of the spring check valve 5 with backpressure function, the pressure difference between the inlet and outlet ports of the hydraulic pump / motor seven 204 is reduced, and the power required to drive the hydraulic pump / motor seven 204 is decreased. At the same time, the eighth proportional flow control valve 608 is also opened through the controller 110 to make the pressure difference between the inlet and outlet ports of the hydraulic pump / motor eight 304 basically zero, reducing the power required to drive the hydraulic pump / motor eight 304 and the driving power of the motor, achieving the purpose of reducing the installed power of the motor and saving energy. When the start of the excavator slewing hydraulic system is stable, the seventh proportional flow control valve 607 and the eighth proportional flow control valve 608 are closed.

[0030] 3. Braking stage During the process that the slewing platform of the excavator rotates uniformly to the right or enters braking after starting and accelerating to the right, due to the large moment of inertia of the slewing platform, it will continue to rotate to the right. At this time, the slewing motor 130 can act as a "hydraulic pump", and the oil fluid is sucked into the oil inlet of the slewing motor 130 through the two non-spring one-way valves 4. There is oil fluid with a relatively high pressure at the oil outlet of the slewing motor 130, which pushes the hydraulic pump / motor 8304 to rotate. The hydraulic pump / motor 8304 is the "load", and at this time, the slewing motor 130 drives the hydraulic pump / motor 8304 to work. At the same time, the controller 110 issues an instruction to open the seventh proportional flow control valve 607, reducing the pressure difference between the oil inlet and outlet of the hydraulic pump / motor 7204 to be basically zero, and reducing the power for driving the hydraulic pump / motor 7204. At the same time, the motor 4104 is driven by the hydraulic pump / motor 8304, and the braking energy of the slewing platform is recovered by generating electricity through the motor 4104, and the electric energy generated by the motor 4104 is stored. At the same time, it also prevents the slewing platform from stalling. It not only achieves the purpose of protecting the slewing platform but also achieves the effect of improving the conversion of the braking energy of the slewing motor 130 into electric energy.

[0031] The working process and control principle of the stick and the bucket are the same as those of the boom, but the actual working conditions are slightly different. The difference is that the gravitational potential energy of the bucket and the stick is less than that of the boom. Therefore, the energy recovery effect of the hydraulic systems of the stick and the bucket is slightly worse.

Claims

1. A hydraulic system integrating drive and recovery, comprising a plurality of actuators and a drive circuit device for controlling the actuators, characterized in that: The actuator is a hydraulic cylinder or / and a rotary motor (130), the drive circuit device is respectively provided with a motor, each motor is respectively provided with a driver, a controller (110) is provided and connected to each driver, the drive circuit device comprises a control circuit respectively connected to the actuator, the control circuit components specifically comprise: a motor, two hydraulic pumps / motors, a springless check valve (4), a spring check valve (5), and two reversing valves; wherein the motor drive is connected to the two hydraulic pumps / motors, the oil outlets of the two hydraulic pumps / motors are respectively connected to the actuator, the oil inlets of the two hydraulic pumps / motors are respectively connected to the oil tank, and the oil circuits connecting the oil inlets of the two hydraulic pumps / motors and the oil tank are respectively provided with springless check valves. A one-way valve (4) and a one-way valve with a spring (5); the inlet of the non-spring one-way valve (4) is connected to an oil tank, the outlet of the spring one-way valve (5) is connected to the oil tank, a reversing valve is arranged in parallel in the circuit between the inlet and outlet of the hydraulic pump / motor, a non-spring one-way valve (4) and a reversing valve are arranged in parallel in the circuit between the inlet and outlet of the hydraulic pump / motor connected to the rod chamber of the hydraulic cylinder, or a non-spring one-way valve (4) and a reversing valve are arranged in parallel in the circuit between the inlet and outlet of the hydraulic pump / motor of the rotary motor (130), the outlet of the non-spring one-way valve (4) is connected to the inlet of the spring one-way valve (5), the outlets of the two overflow valves (7) are connected to the oil tank, and the controller (110) controls the connection of the two reversing valves respectively.

2. The driving and recycling integrated hydraulic system according to claim 1, characterized in that: The reversing valve is a proportional flow control valve and / or a proportional reversing valve.

3. The driving and recycling integrated hydraulic system according to claim 2, characterized in that: The control circuit elements also include: a relief valve (7) and a pressure sensor (8); the hydraulic pump / motor outlet is respectively connected to the pressure sensor (8) and the relief valve (7); and the controller (110) controls the connection to the pressure sensor (8).

4. The driving and recycling integrated hydraulic system according to claim 3, characterized in that: The actuators are: a boom cylinder (1201), an arm cylinder (1202), a bucket cylinder (1203), and a rotary motor (130). Four drive circuit devices are provided corresponding to the four actuators: drive circuit device 1, drive circuit device 2, drive circuit device 3, and drive circuit device 4. The four drive circuit devices are provided with: motor 1 (101), motor 2 (102), motor 3 (103), and motor 4 (104). Drive circuit device 1 includes: a rod cavity control circuit connected to the rod cavity of the boom cylinder (1201) and a rod cavity control circuit connected to the boom cylinder (1 201) A rodless cavity control circuit of a rodless cavity, wherein the control circuit components specifically include: motor 1 (101), hydraulic pump / motor 1 (201), hydraulic pump / motor 2 (301), a springless check valve (4), a spring check valve (5), a first proportional flow control valve (601), a second proportional flow control valve (602), a relief valve (7), and a pressure sensor (8); wherein motor 1 (101) drives and connects hydraulic pump / motor 1 (201) and hydraulic pump / motor 2 (301), and the oil outlet of hydraulic pump / motor 1 (201) is connected to the rodless cavity of the boom cylinder (1201). The oil outlet of hydraulic pump / motor 2 (301) is connected to the rod chamber of boom cylinder (1201), the oil inlets of hydraulic pump / motor 1 (201) and hydraulic pump / motor 2 (301) are respectively connected to the oil tank, and the oil circuits connecting the oil inlets of hydraulic pump / motor 1 (201) and hydraulic pump / motor 2 (301) to the oil tank are respectively provided with a non-spring check valve (4) and a spring check valve (5), the inlet of the non-spring check valve (4) is connected to the oil tank, and the outlet of the spring check valve (5) is connected to the oil tank, and the circuit between the inlet and outlet of hydraulic pump / motor 1 (201) is provided with a first proportional flow control valve in parallel. A springless check valve (4) and a second proportional flow control valve (602) are arranged in parallel in a circuit between the inlet and outlet of the hydraulic pump / motor 2 (301); the outlet of the springless check valve (4) is connected to the inlet of the spring check valve (5); the outlets of the hydraulic pump / motor 1 (201) and the hydraulic pump / motor 2 (301) are respectively connected to a pressure sensor (8) and a relief valve (7); the outlets of the two relief valves (7) are connected to an oil tank; and the controller (110) controls the connection of the first proportional flow control valve (601), the second proportional flow control valve (602) and the pressure sensor (8) respectively.

5. The driving and recovery integrated hydraulic system according to claim 4, characterized in that: The boom cylinder (1201) is provided with a displacement sensor (140), and the controller (110) controls the connection of the displacement sensor (140).

6. The driving and recycling integrated hydraulic system according to claim 1, characterized in that: The non-spring check valve (4) has zero opening pressure, while the spring check valve (5) has an opening pressure.

7. The driving and recovery integrated hydraulic system according to claim 3, characterized in that: The drive circuit device 4 comprises: a control circuit respectively connected to the inlet and outlet of the rotary motor (130), and the control circuit components specifically comprise: a motor 4 (104), a hydraulic pump / motor 7 (204), a hydraulic pump / motor 8 (304), a springless check valve (4), a spring-loaded check valve (5), a seventh proportional flow control valve (607), an eighth proportional flow control valve (608), a relief valve (7), a pressure sensor (8), and a second springless check valve (4011); wherein the motor 4 (104) is driven to connect the hydraulic pump / motor 7 (204) and the hydraulic pump / motor 8 (304), the oil outlets of the hydraulic pump / motor 7 (204) and the hydraulic pump / motor 8 (304) are respectively connected to the rotary motor (130), the oil inlets of the hydraulic pump / motor 7 (204) and the hydraulic pump / motor 8 (304) are respectively connected to the oil tank, and the oil circuits connecting the oil inlets of the hydraulic pump / motor 7 (204) and the hydraulic pump / motor 8 (304) and the oil tank are respectively provided with springless check valves. A first proportional flow control valve (607) and a second non-spring check valve (4011) are arranged in parallel in the circuit between the inlet and outlet of the hydraulic pump / motor (204), and the outlet of the second non-spring check valve (4011) is connected to the inlet of the spring check valve (5). A second proportional flow control valve (608) and a second non-spring check valve (4) are arranged in parallel in the circuit between the inlet and outlet of the hydraulic pump / motor (304), and the outlet of the non-spring check valve (4) is connected to the inlet of the spring check valve (5). The outlets of the hydraulic pump / motor (204) and the second non-spring check valve (4011) are connected to the inlet of the spring check valve (5). The outlets of the hydraulic pump / motor (204) and the second non-spring check valve (4011) are connected to the inlet of the spring check valve (5). The seventh proportional flow control valve (607), the eighth proportional flow control valve (608) and the pressure sensor (8) are connected to the outlets of the hydraulic pump / motor (204) and the eighth proportional flow control valve (304), respectively. The outlets of the two overflow valves (7) are connected to the oil tank. The controller (110) controls the connection of the seventh proportional flow control valve (607), the eighth proportional flow control valve (608) and the pressure sensor (8), respectively.

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