Energy-saving high-precision press hydraulic system

Abstract

The utility model relates to the technical field of hydraulic systems, and discloses an energy-saving high-precision press hydraulic system, which mainly comprises a hydraulic oil pump directly driven by a servo motor, an actuating oil cylinder, an electromagnetic proportional directional valve, a displacement sensor and a PLC (programmable logic controller) control unit. An outlet of the hydraulic oil pump is connected with the main oil way; a piston rod in the actuating oil cylinder is divided into a rodless cavity and a rod cavity; oil ports of the electromagnetic proportional reversing valve are respectively communicated with corresponding parts and an oil tank; the displacement sensor detects piston rod displacement; the PLC control unit adjusts the opening degree of a valve element of the reversing valve according to the displacement signal, and accurate control over the oil flow is achieved. In addition, a double safety valve, a filter and a pressure stabilizing energy accumulator are arranged on the oil conveying pipe, and an electric switch valve, a pressure sensor and a bypass valve are further arranged. According to the system, the energy utilization efficiency and the working precision are remarkably improved, stable operation of the system is guaranteed, the reliability is enhanced, and the service life is prolonged.

Description

TECHNICAL FIELD

[0001] The utility model relates to the technical field of hydraulic system, concretely is a kind of energy-saving high-precision press hydraulic system. BACKGROUND

[0002] Hydraulic transmission equipment, especially those relying on conventional motor pump group as core power source, in actual operation process, even if only one set of hydraulic actuator (for example, oil cylinder) is configured, according to the diversity and complexity of workpiece process, the pressure required to be applied in the forward or backward direction of actuator is often flexibly adjusted, and it is ensured that it can be stably operated at high-precision speed, so as to meet the processing needs of different load materials.

[0003] However, such equipment has been mostly dependent on manual operation to adjust proportional valve in the past, to realize the adjustment of hydraulic system parameters. This traditional control mode is relatively extensive, and it is difficult to realize accurate adjustment of oil flow, and the accuracy and stability of adjustment result are often difficult to guarantee. This not only leads to a lot of energy waste, but also seriously affects the working accuracy of press and the stability of overall operation. Therefore, an energy-saving high-precision press hydraulic system is proposed. SUMMARY

[0004] (I) Technical problem solved

[0005] In view of the deficiencies of the prior art, the utility model provides an energy-saving high-precision press hydraulic system, which has the advantages of accurate control of oil flow, solves the problems of inaccurate flow control, energy waste, insufficient working accuracy and stability caused by manual adjustment of proportional valve in the prior art.

[0006] (II) Technical scheme

[0007] To realize the above-mentioned purpose of accurate control of oil flow, the utility model provides the following technical scheme:

[0008] An energy-saving high-precision press hydraulic system, comprising:

[0009] A hydraulic oil pump directly driven by a servo motor, the outlet end of which is connected to the main oil circuit of the system through an oil delivery pipe;

[0010] An actuating oil cylinder, which is internally provided with a piston rod, the piston rod separates the cavity of the actuating oil cylinder into independent rodless cavity and rod cavity;

[0011] An electromagnetic proportional reversing valve, the first working oil port of which is connected to the rodless cavity of the actuating oil cylinder through a first connecting pipe, the second working oil port is connected to the rod cavity of the actuating oil cylinder through a second connecting pipe, the pressure port is connected to the output end of the hydraulic oil pump through an oil delivery pipe, and the oil return port is connected to the oil tank through an oil return pipe;

[0012] A displacement sensor is used to detect the axial displacement of the piston rod.

[0013] A PLC control unit is connected with the displacement sensor signal and electrically connected with the electromagnetic proportional reversing valve, and the PLC control unit is configured to receive the real-time displacement signal of the displacement sensor and adjust the opening of the spool of the electromagnetic proportional reversing valve to control the oil flow.

[0014] The utility model discloses preferably technical scheme lies in, first safety valve and second safety valve are set up in sequence on the oil pipe along the oil flow direction, and the pressure relief outlet of first safety valve and second safety valve all is connected with the oil return pipe.

[0015] The utility model discloses preferably technical scheme lies in, the filter is installed between first safety valve and second safety valve on the oil pipe.

[0016] The utility model discloses preferably technical scheme lies in, the bypass pipe is equipped with at the upstream of first safety valve on the oil pipe, the end of bypass pipe is connected with the oil return pipe, and electric switch valve is seted up on bypass pipe, and electric switch valve is electrically connected with PLC control unit.

[0017] The utility model discloses preferably technical scheme lies in, the pressure stabilizing energy accumulator is equipped with at the downstream of second safety valve on the oil pipe for absorbing oil pressure fluctuation.

[0018] The utility model discloses preferably technical scheme lies in, first pressure sensor and second pressure sensor are installed on first connecting pipe and second connecting pipe respectively, and the upstream of first safety valve is provided with third pressure sensor on the oil pipe, and each pressure sensor is connected with PLC control unit and establishes signal.

[0019] The utility model discloses preferably technical scheme lies in, the bypass valve is equipped with on first connecting pipe, and the inlet end of bypass valve is connected on first connecting pipe, and the outlet end is connected into the oil return pipe, and bypass valve is electrically connected with PLC control unit.

[0020] (Three) beneficial effects

[0021] Compared with the prior art, the utility model provides a kind of energy-saving high-precision press hydraulic system, with following beneficial effects:

[0022] The energy-saving high-precision press hydraulic system directly drives hydraulic oil pump by servo motor, realizes accurate control to oil flow in combination with the real-time feedback of PLC control unit and displacement sensor, significantly improves the energy utilization efficiency of system and the working accuracy of press, and reduces energy consumption.

[0023] The energy-saving high-precision press hydraulic system, through the addition of double safety valve, filter and pressure stabilizing accumulator and other components, effectively guarantees the stable operation of the system, and improves the cleanliness and pressure stability of the oil, further enhances the reliability and service life of the system. BRIEF DESCRIPTION OF DRAWINGS

[0024] Fig. 1 It is a hydraulic system structure schematic diagram of the utility model;

[0025] Fig. 2 It is a connection relationship structure diagram of the PLC control unit and other components in the utility model.

[0026] In the drawing: 1, servo motor; 2, hydraulic oil pump; 3, actuating oil cylinder; 4, electromagnetic proportional reversing valve; 5, displacement sensor; 6, PLC control unit; 7, first safety valve; 8, second safety valve; 9, filter; 10, bypass pipe; 11, electric on-off valve; 12, pressure stabilizing accumulator; 13, first pressure sensor; 14, second pressure sensor; 15, third pressure sensor; 16, bypass valve; 17, oil tank. DETAILED DESCRIPTION

[0027] The technical solutions in the embodiments of the utility model will be clearly and completely described below with reference to the drawings in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, rather than all the embodiments. Based on the embodiments of the utility model, all other embodiments obtained by those skilled in the art without creative labor belong to the protection scope of the utility model.

[0028] In the description of the utility model, it is understood that the terms "center", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer" and the like indicate the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the utility model and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the utility model.

[0029] In the description of the utility model, it should be explained that, unless otherwise explicitly specified and limited, the terms "mounting", "connection", "connection" should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or integrally connected; it can be directly connected, or indirectly connected through an intermediate medium; it can be the communication inside two elements. For those skilled in the art, the specific meaning of the above terms in the utility model can be understood according to the specific circumstances.

[0030] Please refer toFigs. 1-2 An energy-saving high-precision press hydraulic system comprises:

[0031] A hydraulic oil pump 2 directly driven by a servo motor 1, the outlet end of which is connected to the main oil circuit of the system through an oil delivery pipe connection system;

[0032] An actuating oil cylinder 3, which is internally provided with a piston rod that separates the cavity of the actuating oil cylinder 3 into a rodless cavity and a rod cavity that are independent of each other;

[0033] An electromagnetic proportional reversing valve 4, the first working oil port of which is connected to the rodless cavity of the actuating oil cylinder 3 through a first connecting pipe, the second working oil port of which is connected to the rod cavity of the actuating oil cylinder 3 through a second connecting pipe, the pressure port of which is connected to the output end of the hydraulic oil pump 2 through an oil delivery pipe, and the return oil port of which is connected to the oil tank 17 through a return oil pipe;

[0034] A displacement sensor 5 for detecting the axial displacement of the piston rod;

[0035] A PLC control unit 6, which is signal-connected to the displacement sensor 5 and electrically connected to the electromagnetic proportional reversing valve 4, is configured to receive the real-time displacement signal of the displacement sensor 5 and adjust the opening degree of the valve core of the electromagnetic proportional reversing valve 4 to control the oil flow.

[0036] The energy-saving high-precision press hydraulic system directly drives the hydraulic oil pump 2 by the servo motor 1, and realizes the precise control of the oil flow through the real-time feedback of the PLC control unit 6 and the displacement sensor 5, thereby significantly improving the energy utilization efficiency of the system and the working precision of the press and reducing the energy consumption.

[0037] In this embodiment, a first safety valve 7 and a second safety valve 8 are sequentially arranged on the oil delivery pipe in the direction of oil flow, and the pressure relief outlets of the first safety valve 7 and the second safety valve 8 are both connected to the return oil pipe.

[0038] It should be noted that the rated pressure of the first safety valve 7 and the second safety valve 8 is both greater than the system rated pressure by 0.5-1.0 Mpa.

[0039] It should be further noted that the double safety valves are an important safety protection mechanism. When the system pressure exceeds the rated pressure of the first safety valve 7, the first safety valve 7 is opened to discharge the excess oil through the pressure relief outlet to the return oil pipe and back to the oil tank 17, thereby avoiding the continuous rise of the system pressure and causing damage to the components such as the hydraulic oil pump 2 and the actuating oil cylinder 3. The second safety valve 8 serves as the second line of defense. When the first safety valve 7 fails to normally open or the system pressure abnormally and sharply rises beyond the rated pressure of the first safety valve 7, the second safety valve 8 is opened to further ensure the safety of the system and prevent serious faults such as oil pipe rupture and component damage from occurring due to overpressure.

[0040] In this embodiment, the filter 9 is installed between the first safety valve 7 and the second safety valve 8.

[0041] It should be noted that the filter 9 has a filtering precision of 100 μm. During the circulation of the oil in the hydraulic system, impurities such as metal particles and rubber debris may be mixed into the oil. These impurities may wear the hydraulic components and affect the working precision and stability of the system. The filter 9 can effectively remove the impurities in the oil, ensure the cleanliness of the oil entering the subsequent system, prolong the service life of the components in the system, and improve the reliability of the system.

[0042] In this embodiment, the bypass pipe 10 is provided upstream of the first safety valve 7, the end of the bypass pipe 10 is connected to the oil return pipe, and the electrically operated on-off valve 11 is arranged on the bypass pipe 10 and electrically connected to the PLC control unit 6.

[0043] It should be noted that the bypass pipe 10 and the electrically operated on-off valve 11 are provided upstream of the first safety valve 7, and the electrically operated on-off valve 11 is electrically connected to the PLC control unit 6. When the system needs to be maintained, repaired, or an abnormal situation occurs, the PLC control unit 6 can control the electrically operated on-off valve 11 to open, so that the oil flows back to the oil tank 17 through the bypass pipe 10, thereby achieving rapid pressure relief of the system. In this way, the high-pressure oil in the system can be prevented from causing harm to the operator during disassembly or maintenance operation, and the system can be conveniently maintained and debugged.

[0044] In this embodiment, the pressure stabilizing accumulator 12 is provided downstream of the second safety valve 8 to absorb the pressure fluctuation of the oil.

[0045] It should be noted that the pressure stabilizing accumulator 12 is installed downstream of the second safety valve 8 of the oil pipe, and its main function is to absorb the pressure fluctuation of the oil. During the operation of the hydraulic system, due to the periodic operation of the hydraulic oil pump 2 and the movement of the actuator cylinder 3, the pressure of the oil may fluctuate. Pressure fluctuation may cause system vibration, noise increase, and affect the stability and working precision of the system. The pressure stabilizing accumulator 12 can store excess energy when the oil pressure rises and release the stored energy when the oil pressure decreases, thereby stabilizing the oil pressure and improving the stability and reliability of the system.

[0046] In this embodiment, the first pressure sensor 13 and the second pressure sensor 14 are respectively installed on the first connecting pipe and the second connecting pipe, and the third pressure sensor 15 is arranged upstream of the first safety valve 7 of the oil pipe. Each pressure sensor is signal connected to the PLC control unit 6.

[0047] It should be noted that the first connecting pipe and the second connecting pipe are respectively provided with the first pressure sensor 13 and the second pressure sensor 14 for monitoring the pressure of the rodless cavity and the rod cavity of the actuating oil cylinder 3 in real time. The third pressure sensor 15 is arranged upstream of the first safety valve 7 on the oil delivery pipe for monitoring the pressure at the output end of the hydraulic oil pump 2. Each pressure sensor is signal connected with the PLC control unit 6, and the PLC control unit 6 can judge and adjust the working state of the system according to the real-time pressure signals fed back by the pressure sensors. For example, when the pressure of a certain cavity of the actuating oil cylinder 3 is abnormal, the PLC control unit 6 can timely adjust the opening degree of the valve core of the electromagnetic proportional reversing valve 4 to control the oil flow and ensure the stability of the system pressure.

[0048] In the embodiment, the first connecting pipe is provided with a bypass valve 16, the inlet end of the bypass valve 16 is connected to the first connecting pipe, the outlet end is connected to the oil return pipe, and the bypass valve 16 is electrically connected with the PLC control unit 6.

[0049] It should be noted that the bypass valve 16 functions to make the oil in the rodless cavity of the actuating oil cylinder 3 directly flow back to the oil tank 17 under certain conditions. When the system needs to quickly reduce the pressure of the rodless cavity of the actuating oil cylinder 3, or needs to control the movement speed of the actuating oil cylinder 3 under certain special working conditions, the PLC control unit 6 can control the bypass valve 16 to open to realize the rapid return flow of the oil, thereby flexibly adjusting the working state of the system.

[0050] The energy-saving high-precision press hydraulic system effectively guarantees the stable operation of the system by additionally arranging components such as double safety valves, filters 9 and pressure stabilizing accumulators 12, improves the cleanliness and stability of the oil, and further enhances the reliability and service life of the system.

[0051] Working principle: the servo motor 1 is started, directly drives the hydraulic oil pump 2 to work, the hydraulic oil pump 2 is inhaled the oil liquid in the oil tank 17 and is transported to the system main oil way through oil pipe.This time, the electric switch valve 11 is in the closed state, and the oil liquid normally flows to the system.The third pressure sensor 15 monitors the pressure of the output end of the hydraulic oil pump 2 in real time, and the signal is transmitted to the PLC control unit 6, and the PLC control unit 6 judges whether the system pressure is normal according to the set parameter.The PLC control unit 6 adjusts the valve core opening degree of the electromagnetic proportional reversing valve 4 according to the preset working procedure and the real-time displacement signal of the piston rod feedback by the displacement sensor 5.If the piston rod of the actuating oil cylinder 3 needs to be extended, the PLC control unit 6 controls the electromagnetic proportional reversing valve 4 to make the pressure port and the first working oil port communicate, and the oil liquid output by the hydraulic oil pump 2 enters the rodless cavity of the actuating oil cylinder 3 through the oil pipe, the electromagnetic proportional reversing valve 4, the first connecting pipe, and pushes the piston rod to extend;At the same time, the oil liquid in the rod cavity flows back to the oil tank 17 through the second connecting pipe, the second working oil port of the electromagnetic proportional reversing valve 4 and the oil return pipe.In this process, the first pressure sensor 13 and the second pressure sensor 14 monitor the pressure of the rodless cavity and the rod cavity in real time, and the signal is fed back to the PLC control unit 6, and the PLC control unit 6 further accurately adjusts the valve core opening degree of the electromagnetic proportional reversing valve 4 according to the pressure change, to control the oil liquid flow, realize the accurate control to the movement speed and position of the piston rod.

[0052] Although the embodiments of the utility model have been shown and described, it can be understood by those skilled in the art that various changes, modifications, replacements and variations can be made to these embodiments without departing from the principles and spirits of the utility model, the scope of the utility model is defined by the appended claims and their equivalents.

Claims

1. An energy-saving, high-precision hydraulic system for a press, characterized in that... ,include: The hydraulic oil pump is directly driven by a servo motor, and its outlet end is connected to the main oil circuit of the system through an oil delivery pipe; The actuating cylinder has a piston rod inside, which divides the cylinder's chamber into two independent rodless chambers and rod chambers. The electromagnetic proportional directional valve has a first working port connected to the rodless chamber of the actuating cylinder through a first connecting pipe, a second working port connected to the rod chamber of the actuating cylinder through a second connecting pipe, a pressure port connected to the output end of the hydraulic oil pump through an oil supply pipe, and a return port connected to the oil tank through a return pipe. A displacement sensor is used to detect the axial displacement of the piston rod. The PLC control unit is connected to the displacement sensor signal and electrically connected to the electromagnetic proportional directional valve. The PLC control unit is configured to receive the real-time displacement signal from the displacement sensor and adjust the valve core opening of the electromagnetic proportional directional valve to control the oil flow.

2. The energy-saving high-precision press hydraulic system according to claim 1, characterized in that: The oil pipeline is provided with a first safety valve and a second safety valve in sequence along the direction of oil flow, and the pressure relief outlets of the first safety valve and the second safety valve are both connected to the return oil pipeline.

3. The energy-saving high-precision press hydraulic system according to claim 2, characterized in that: A filter is installed between the first safety valve and the second safety valve in the oil pipeline.

4. The energy-saving high-precision press hydraulic system according to claim 3, characterized in that: The oil supply pipe is provided with a bypass pipe upstream of the first safety valve. The end of the bypass pipe is connected to the return oil pipe, and an electric switching valve is provided on the bypass pipe. The electric switching valve is electrically connected to the PLC control unit.

5. The energy-saving high-precision press hydraulic system according to claim 4, characterized in that: The oil pipeline is equipped with a pressure accumulator downstream of the second safety valve to absorb oil pressure fluctuations.

6. The energy-saving high-precision press hydraulic system according to claim 5, characterized in that: A first pressure sensor and a second pressure sensor are respectively installed on the first connecting pipe and the second connecting pipe. A third pressure sensor is installed upstream of the first safety valve on the oil pipeline. Each pressure sensor is connected to the PLC control unit.

7. The energy-saving high-precision press hydraulic system according to claim 1, characterized in that: The first connecting pipe is equipped with a bypass valve. The inlet end of the bypass valve is connected to the first connecting pipe, and the outlet end is connected to the return oil pipe. The bypass valve is also electrically connected to the PLC control unit.

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