Hydraulic system capable of recovering and recycling energy

Abstract

The utility model relates to the technical field of hydraulic control systems, in particular to a hydraulic system capable of recovering and recycling energy. Comprising a motor oil pump set, a main cylinder and a buffering cylinder, an outlet of the motor oil pump set is connected with the main cylinder through a pipeline, an oil way control unit, a back pressure adjusting unit and a safety protection unit are connected between the outlet of the motor oil pump set and the buffering cylinder through pipelines, and the system further comprises a pressure relief unit. The hydraulic system has the advantages that when the buffering cylinder returns, the energy accumulator can store pressure oil in the piston cavity of the buffering cylinder, energy recovery is carried out, and energy consumption of the system can be reduced. And when pressing is finished, the pressure oil in the energy accumulator can be released, enters the buffer cylinder and ejects the piston rod of the buffer cylinder, a motor oil pump set does not need to be used for providing the pressure oil, the piston rod of the buffer cylinder automatically ejects out, the system pressing rhythm is accelerated, and the pressing cycle time is shortened. And the throttle valve can adjust the back pressure of the piston cavity of the buffering cylinder, and is suitable for various oil cylinders.

Description

Technical Field

[0001] This utility model relates to the field of hydraulic control system technology, and in particular to a hydraulic system for energy recovery and recycling. Background Technology

[0002] Currently, it is widely known that buffer cylinders are widely used in various mechanical equipment and industrial systems. They are also an important component in hydraulic press systems, primarily performing the following functions: 1. Vibration damping: In mechanical systems, irregular vibrations or external impacts during movement can easily damage or cause malfunctions. Buffer cylinders absorb and reduce these vibrations and impacts, protecting the normal operation of the mechanical equipment. 2. Kinetic energy absorption: When the slider is descending, the buffer cylinder needs to absorb and adjust the kinetic energy generated during the movement. By changing its own volume, the buffer cylinder absorbs and releases kinetic energy, achieving smooth and stable movement.

[0003] In conventional hydraulic presses, the control of the buffer cylinder is achieved by using a motor-driven oil pump unit to supply pressurized oil to push the cylinder outwards, and then using the same unit to supply pressurized oil to return it to its original position. This results in the pressurized oil in the buffer cylinder being discharged into the oil tank each time, causing energy loss. Furthermore, when multiple cylinders share a single motor-driven oil pump unit, they need to operate sequentially, which adds a waiting time.

[0004] To address the above problems, this utility model provides a hydraulic system for energy recovery and recycling, which can recover energy from the buffer cylinder, reducing energy loss; it can also allow the piston rod of the buffer cylinder to automatically extend, reducing waiting time. Summary of the Invention

[0005] The purpose of this invention is to address the problems existing in the prior art by proposing a hydraulic system for energy recovery and recycling. To achieve the above objective, this invention adopts the following technical solution:

[0006] A hydraulic system for energy recovery and recycling of a buffer cylinder includes an electric motor oil pump assembly, a main cylinder, and a buffer cylinder. The outlet of the electric motor oil pump assembly is connected to the main cylinder via a pipeline. An oil circuit control unit, a back pressure adjustment unit, and a safety protection unit are connected between the outlet of the electric motor oil pump assembly and the buffer cylinder via a pipeline. The oil circuit control unit is connected to the outlet of the electric motor oil pump assembly and includes a first cartridge valve and a first solenoid directional valve. The first cartridge valve is connected to the outlet of the electric motor oil pump assembly, and the control port of the first cartridge valve is connected to the A port of the first solenoid directional valve via a shuttle valve. The T port of the first solenoid directional valve is connected to an oil tank.

[0007] The back pressure regulating unit includes a one-way valve and a throttle valve. The one-way valve A port is connected to the working oil port of the first cartridge valve, and the one-way valve B port is connected to the buffer cylinder plug chamber.

[0008] The safety protection unit includes a second cartridge valve and a safety relief valve. The working port of the second cartridge valve is connected to the branch between the check valve and the buffer cylinder. The inlet of the safety relief valve is connected to the control port of the second cartridge valve. An accumulator is also connected to the branch between the first cartridge valve and the check valve.

[0009] Furthermore, it also includes a pressure relief unit connected to the oil circuit of the accumulator. The pressure relief unit includes a second solenoid directional valve and a third cartridge valve. The A port of the second solenoid directional valve is connected to the control oil port of the third cartridge valve. The A port of the third cartridge valve is connected to the oil tank. The C port of the third cartridge valve is connected to the accumulator. The third cartridge valve and the branch of the accumulator are connected to the P port of the second solenoid directional valve through a pipeline.

[0010] Furthermore, an accumulator pressure sensor is connected to the oil line between the accumulator and the pressure relief unit.

[0011] Furthermore, the shuttle valve A port is connected to any point between the back pressure regulating unit and the pressure relief unit, and the shuttle valve B port is connected to the first electromagnetic directional valve A port.

[0012] Furthermore, a hydraulic cylinder pressure gauge is connected between the back pressure adjustment unit and the safety protection unit.

[0013] Compared with existing technologies, this utility model provides a hydraulic system for energy recovery and recycling. The advantages of this utility model are:

[0014] 1. During the return stroke of the buffer cylinder, the accumulator can store the pressurized oil in the buffer cylinder plug chamber for energy recovery, which can reduce the energy consumption of the system.

[0015] 2. When the pressing ends, the pressure oil in the accumulator can be released and enter the buffer cylinder, pushing out the piston rod of the buffer cylinder. There is no need to use the motor oil pump group to provide pressure oil. The piston rod of the buffer cylinder is automatically pushed out, which speeds up the pressing cycle of the system and reduces the pressing cycle time.

[0016] 3. The throttle valve can adjust the back pressure of the buffer cylinder piston chamber and is suitable for use in various hydraulic cylinders. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the hydraulic principle in the utility model.

[0018] In the diagram: 1. First cartridge valve, 2. First solenoid directional valve, 3. Check valve, 4. Throttle valve, 5. Buffer cylinder, 6. Master cylinder, 7. Cylinder pressure gauge, 8. Second cartridge valve, 9. Safety relief valve, 10. Accumulator, 11. Accumulator pressure sensor, 12. Second solenoid directional valve, 13. Third cartridge valve, 14. Shuttle valve. Detailed Implementation

[0019] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0020] Example 1, please refer to Figure 1 As shown, a hydraulic system for energy recovery and recycling includes an electric motor oil pump assembly, a main cylinder 6, and a buffer cylinder 5. The outlet of the electric motor oil pump assembly is connected to the main cylinder 6 via a pipeline. An oil circuit control unit, a back pressure adjustment unit, and a safety protection unit are connected between the outlet of the electric motor oil pump assembly and the buffer cylinder 5 via a pipeline.

[0021] The oil circuit control unit is connected to the outlet of the motor oil pump group and includes a first cartridge valve 1 and a first solenoid directional valve 2. The first cartridge valve 1 is connected to the outlet of the motor oil pump group. The control port of the first cartridge valve 1 is connected to the A port of the first solenoid directional valve 2 through a shuttle valve 14. The T port of the first solenoid directional valve 2 is connected to the oil tank.

[0022] The back pressure regulating unit includes a one-way valve 3 and a throttle valve 4. Port A of the one-way valve 3 is connected to the working oil port of the first cartridge valve 1, and port B of the one-way valve 3 is connected to the plug chamber of the buffer cylinder 5. In this embodiment, there are two buffer cylinders.

[0023] The safety protection unit includes a second cartridge valve 8 and a safety relief valve 9. The working port of the second cartridge valve 8 is connected to the branch between the check valve 3 and the buffer cylinder 5. The inlet of the safety relief valve 9 is connected to the control port of the second cartridge valve 8. An accumulator 10 is also connected to the branch between the first cartridge valve 1 and the check valve 3.

[0024] Example 2, as Figure 1 As shown, it also includes a pressure relief unit, which is connected to the oil line of the accumulator 10. The pressure relief unit includes a second solenoid directional valve 12 and a third cartridge valve 13. The A port of the second solenoid directional valve 12 is connected to the control oil port of the third cartridge valve 13. The A port of the third cartridge valve 13 is connected to the oil tank. The C port of the third cartridge valve 13 is connected to the accumulator 10. The branch of the third cartridge valve 13 and the accumulator 10 is connected to the P port of the second solenoid directional valve 12 through a pipeline.

[0025] An accumulator pressure sensor 11 is connected to the oil line between the accumulator 10 and the pressure relief unit.

[0026] The A port of the shuttle valve 14 is connected to any point between the back pressure regulating unit and the pressure relief unit, and the B port of the shuttle valve 14 is connected to the A port of the first electromagnetic reversing valve 2.

[0027] A hydraulic cylinder pressure gauge 7 is connected between the back pressure adjustment unit and the safety protection unit.

[0028] The hydraulic cylinder pressure gauge 7 reads the pressure value of the liquid in the pipeline. When adjusting the safety relief valve 9, the pressure value displayed on the hydraulic cylinder pressure gauge 7 is used to adjust the safety relief valve 9 to the system's set pressure value. This ensures that the system pressure does not exceed the allowable value, thereby preventing accidents caused by excessive pressure.

[0029] The specific operation involves adjusting the safety relief valve 9 by first reducing the valve opening of the throttle valve 4. When the main cylinder 6 drives the slider downward, the pressure oil in the buffer cylinder 5 flows towards the safety protection unit. Then, adjust the handle of the safety relief valve 9 so that the oil cylinder pressure gauge 7 displays the required pressure value. In this embodiment, the pressure value of the safety relief valve 9 is 31.5 MPa. At this point, seal the handle of the safety relief valve 9 with a lead seal to indicate that it is not adjustable. The safety relief valve 9 is then properly adjusted.

[0030] When the accumulator 10 recovers energy from the buffer cylinder 5 for energy storage, the accumulator 10 can be any of the known accumulators such as a bladder accumulator or a piston accumulator. Specifically, after the safety relief valve 9 adjusts the set pressure, the pressure oil from the buffer cylinder 5 enters the accumulator 10 through the throttle valve 4. The valve orifice of the throttle valve 4 can be adjusted, thereby adjusting the back pressure of the buffer cylinder 5's plug chamber to adapt to different types of cylinders. In this embodiment, when the throttle valve 4 adjusts the back pressure of the buffer cylinder 5's plug chamber, the pressure value displayed on the cylinder pressure gauge 7 is 10 MPa. The throttle valve 4 can be adjusted manually or automatically. Generally, the rise pressure and rise time of the buffer cylinder 5 at this time are determined by the opening size of the throttle valve 4. A smaller opening of the throttle valve 4 shortens the rise pressure and rise time, while a larger opening prolongs the rise pressure and rise time. The safety relief valve 9 protects the entire system, ensuring that the system pressure does not exceed the set safety pressure value.

[0031] The main function of back pressure is to increase the applied force by changing the pressure. Back pressure allows the hydraulic system to maintain a certain pressure on the low-pressure side, preventing abnormal operation of the actuator. Furthermore, back pressure increases the smoothness of movement, especially when the external load suddenly decreases to zero, acting as a buffer and vibration damper for the system. It improves the smoothness of the movement of the buffer cylinder 5 and also reduces its creeping phenomenon.

[0032] Example 3, a control method, based on the hydraulic system for energy recovery and recycling described in Examples 1 and 2, includes the following steps:

[0033] S1. After the system establishes a stable pressure, the first electromagnetic reversing valve 2 is energized, and the pressurized oil in the motor oil pump group enters the buffer cylinder 5 and accumulator 10 through the first cartridge valve 1.

[0034] S2. Pressurized oil enters the buffer cylinder 5, pushing out the piston rod of the buffer cylinder 5;

[0035] S3, when the main cylinder 6 is pressed down, the pressure oil in the plug chamber of the buffer cylinder 5 will flow into the accumulator 10 through the throttle valve 4 to store energy;

[0036] S4. After pressing is completed, the main cylinder 6 returns, and the pressure oil in the accumulator 10 enters the buffer cylinder 5 through the one-way valve 3, pushing out the piston rod of the buffer cylinder 5.

[0037] S3 also includes S31, in which the throttle valve 4 can adjust the back pressure of the buffer cylinder 5 when the accumulator 10 is storing energy.

[0038] In this embodiment, to calculate the energy absorbed by the buffer cylinder 5 when the piston rod of the buffer cylinder 5 reaches its end point, the kinetic energy E of the buffer cylinder 5 is calculated. k The calculation formula can be expressed as:

[0039] ,

[0040] Where m is the load mass, v is the instantaneous velocity upon impact, g is the gravitational acceleration, S is the stroke of buffer cylinder 5, and α is the inclination angle of the inclined surface inside buffer cylinder 5.

[0041] In this embodiment, we assume the load mass of the buffer cylinder 5 is 10 kg, the instantaneous velocity of impact is v = 1.5 m / s, the stroke of the buffer 5 is S = 20 mm, the inclination angle of the inclined surface inside the buffer cylinder 5 is α = 0° (i.e., perpendicular impact), and the gravitational acceleration is g = 9.81 m / s². 2 ,

[0042] The kinetic energy E of buffer cylinder 5 k The calculation is as follows:

[0043]

[0044] The kinetic energy E of buffer cylinder 5 k Calculations are crucial for designing a suitable buffer system to ensure that energy is effectively absorbed when the piston rod impacts the end cap, thereby reducing impact and vibration on the mechanical structure. The kinetic energy E of the buffer cylinder 5 is calculated. k This helps us understand the movement of buffer cylinder 5, and the kinetic energy E of buffer cylinder 5. kThe size of the buffer cylinder 5 directly affects its motion characteristics, including acceleration and deceleration speeds. This is achieved by controlling the kinetic energy E of the buffer cylinder 5. k This allows for more precise control of the movement of the buffer cylinder 5 to meet specific process requirements.

[0045] The working principle of this utility model is as follows: (continued from...) Figure 1 When the system is started, the motor-driven oil pump unit provides pressurized oil to the system. When the first solenoid directional valve 2 is energized, ports A and T of the first solenoid directional valve 2 are connected. The control oil at port C of the first cartridge valve 1 flows back to the oil tank through port T of the first solenoid directional valve 2. The pressurized oil in the motor-driven oil pump unit flows to the accumulator 10 for energy storage through port B of the first cartridge valve 1. At the same time, the pressurized oil flows to the buffer cylinder 5 through the check valve 3, pushing out the piston rod of the buffer cylinder 5. When the accumulator pressure sensor 11 detects that the accumulator 10 has reached the system set pressure, the first solenoid directional valve 2 is de-energized, and ports P and A of the first solenoid directional valve 2 are connected. When the valve core of the first cartridge valve 1 closes, the accumulator 10 stops storing energy. When the main cylinder 6 presses down, the piston rod of the buffer cylinder 5 contacts the slider, and the piston rod of the buffer cylinder 5 is passively pressed down. At this time, the valve port of the adjustable throttle valve 4 is used to apply back pressure. The pressure oil in the buffer cylinder 5 flows to the accumulator 10 for energy storage through the throttle valve 4, and also flows to the first cartridge valve 1. However, at this time, port A of the shuttle valve 14 will also be opened by the pressure oil and enter the tail of the first cartridge valve 1. Port B of the first cartridge valve 1 will not be opened by the pressure oil, and the pressure oil in the buffer cylinder 5 will only flow into the accumulator 10 to continue storing energy for the accumulator 10. When the pressure oil flows towards the accumulator 10, it will also flow towards the third cartridge valve 13. However, at this time, the pressure oil will pass through port P of the second solenoid directional valve 12, and then from port A of the second solenoid directional valve 12 into port B of the third cartridge valve 13, so that the pressure oil will only flow into the accumulator 10. After pressing is completed, the main cylinder 6 returns. During the return of the main cylinder 6, the load on the buffer cylinder 5 is reduced, and the pressure oil of the accumulator 10 enters the plug chamber of the buffer cylinder 5 through the one-way valve 3, pushing the piston rod of the buffer cylinder 5 into place. This cycle continues.

[0046] If the system pressure exceeds the system's set pressure, the safety protection unit can automatically release the excess pressure oil into the oil tank, protecting the pressure stability of the entire system and preventing the buffer cylinder 5 from being impacted by high pressure.

[0047] When maintenance or pressure relief is required, the second solenoid directional valve 12 is energized, and its ports A and T are connected. Control oil from the tail of the third cartridge valve 13 flows through port B of the third cartridge valve 13, then sequentially through ports A and T of the second solenoid directional valve 12, before returning to the oil tank. Pressure oil in the accumulator 10 enters port C of the third cartridge valve 13 and returns to the oil tank through port A of the third cartridge valve 13. After the accumulator 10 and the buffer cylinder 5 have been depressurized, maintenance can proceed.

[0048] In summary, the above description is merely a preferred embodiment of the present utility model, but the scope of protection of the present utility model is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present utility model, based on the technical solution and inventive concept of the present utility model, should be included within the scope of protection of the present utility model.

Claims

1. An energy recovery and recycling hydraulic system, comprising a motor oil pump group, a main cylinder (6) and a buffer cylinder (5), the motor oil pump group outlet is connected with the main cylinder (6) through a pipeline, and an oil path control unit, a back pressure adjusting unit and a safety protection unit are connected between the motor oil pump group outlet and the buffer cylinder (5), characterized in that: The oil path control unit is connected to the motor oil pump group outlet, comprising a first cartridge valve (1) and a first electromagnetic reversing valve (2), the first cartridge valve (1) is connected to the motor oil pump group outlet, the control oil port of the first cartridge valve (1) is connected to the A port of the first electromagnetic reversing valve (2) through a shuttle valve (14), and the T port of the first electromagnetic reversing valve (2) is connected to an oil tank; the back pressure adjusting unit comprises a check valve (3) and a throttle valve (4), the A port of the check valve (3) is connected to the working oil port of the first cartridge valve (1), and the B port of the check valve (3) is connected to the plug cavity of the buffer cylinder (5); the safety protection unit comprises a second cartridge valve (8) and a safety overflow valve (9), the working oil port of the second cartridge valve (8) is connected to a branch between the check valve (3) and the buffer cylinder (5), and the inlet of the safety overflow valve (9) is connected to the control oil port of the second cartridge valve (8); an accumulator (10) is further connected to the branch between the first cartridge valve (1) and the check valve (3).

2. The hydraulic system for energy recovery and recycling of claim 1, wherein: A pressure relief unit is further included, the pressure relief unit comprises a second electromagnetic reversing valve (12) and a third cartridge valve (13), the A port of the second electromagnetic reversing valve (12) is connected to the control oil port of the third cartridge valve (13), the A port of the third cartridge valve (13) is connected to the oil tank, the C port of the third cartridge valve (13) is connected to the accumulator (10), and the branch between the third cartridge valve (13) and the accumulator (10) is connected to the P port of the second electromagnetic reversing valve (12) through a pipeline.

3. The hydraulic system for energy recovery and recycling of claim 2, wherein: An accumulator pressure sensor (11) is connected to the oil path between the accumulator (10) and the pressure relief unit.

4. The hydraulic system for energy recovery and recycling of claim 1, wherein: The A port of the shuttle valve (14) is connected to any point between the back pressure adjusting unit and the pressure relief unit, and the B port of the shuttle valve (14) is connected to the A port of the first electromagnetic reversing valve (2).

5. The hydraulic system for energy recovery and recycling of claim 1, wherein: An oil cylinder pressure gauge (7) is connected between the back pressure adjusting unit and the safety protection unit.

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